WO2024245527A1

WO2024245527A1 - Treatment of pneumonia and ards with inhibitors of c5a and il-6 activity

Info

Publication number: WO2024245527A1
Application number: PCT/EP2023/064290
Authority: WO
Inventors: Niels Christoph Riedemann; Renfeng Guo
Original assignee: Inflarx Gmbh
Priority date: 2023-05-26
Filing date: 2023-05-26
Publication date: 2024-12-05

Abstract

The present invention relates to an inhibitor of C5a activity and an inhibitor of IL-6 activity for use in the treatment of infectious pneumonia and infectious acute respiratory distress syndrome (ARDS). In further aspects administration regimes and kit of parts are referred to.

Description

Treatment of pneumonia and ARDS with inhibitors of C5a and IL-6 activity

Background of the Invention

C5a

C5a is a 74 amino acid spanning split product of its “mother molecule” C5 and represents one endpoint of the complement activation cascade. It can be generated through activation of at least three well-described pathways (the alternative, the classical and the MBL pathway). All pathways merge at the level of C3, forming the C5- or alternative C5 convertase leading to cleavage of C5 into C5a and C5b. The latter binds with C6, C7, C8 and multiple C9 molecules ultimately leading to formation of pores in e.g. bacterial membranes (terminal Membrane Attack Complex = MAC). C5a is generated when the complement system is activated in settings of inflammation and other immunological and inflammatory disorders / diseases.

Among the complement activation products, C5a is one of the most potent inflammatory peptides, with a broad spectrum of functions (Guo and Ward, 2005). C5a exerts its effects through the high-affinity C5a receptors (C5aR and C5L2) (Ward, 2009). C5aR belongs to the rhodopsin family of G-protein-coupled receptors with seven transmembrane segments; C5L2 has a similar structure but appears not to be G-protein-coupled. It is currently believed that C5a exerts its biological functions primarily through C5a-C5aR interaction. However, some reports demonstrate signaling also through C5L2 activation (Rittirsch and others, 2008).

C5aR is widely expressed on myeloid cells including neutrophils, eosinophils, basophils, and monocytes, and non-myeloid cells in many organs, especially in the lung and liver, indicative of the importance of C5a/C5aR signaling. Widespread up-regulation of C5aR expression occurs during the onset of sepsis, and blockade of C5a/C5aR interaction by anti- C5a, or anti-C5aR antibodies, or C5aR antagonists renders highly protective effects in rodent models of sepsis (Czermak and others, 1999; Huber-Lang and others, 2001; Riedemann and others, 2002).

C5a has been reported to exert numerous pro-inflammatory responses. For example, C5a stimulates the synthesis and release from human leukocytes of pro-inflammatory cytokines such as TNF-a, IL-ip, IL-6, IL-8, and macrophage migration inhibitory factor (MIF) (Hopken U et al. 1996. Eur J Immunol 26(5): 1103-1109; Riedemann NC et al. 2004. J Immunol 173(2): 1355-1359; Stricter RM et al. 1992. Am J Pathol 141(2):397-407). C5a produces a strong synergistic effect with LPS in production of TNF-a, macrophage inflammatory protein (MIP)-2, cytokine-induced neutrophil chemoattractant (CINC)-l, and IL-ip in alveolar epithelial cells (Riedemann NC et al. 2002. J. Immunol. 168(4): 1919-1925; Rittirsch D et al. 2008. Nat Rev Immunol 8(10):776-787).

C5a has a variety of biological functions (Guo and Ward, 2005). C5a is a strong chemoattractant for neutrophils and also has chemotactic activity for monocytes and macrophages. C5a causes an oxidative burst (02 consumption) in neutrophils and enhances phagocytosis and release of granular enzymes. C5a has also been found to be a vasodilator. C5a has been shown to be involved in modulation of cytokine expression from various cell types and to enhance expression of adhesion molecule expression on neutrophils. High doses of C5a can lead to nonspecific chemotactic “desensitization” of neutrophils, thereby causing broad dysfunction.

Interleukin-6 (IL-6)

IL-6 has a fundamental role in inflammation, immune regulation, hematopoiesis, host defense, homeostasis, and tissue regeneration. It is produced by a wide range of hematopoietic and somatic cells that influences numerous cell types with multiple biological functions.

IL-6 plays a critical role in the immune response by stimulating the growth and differentiation of T and B cells, as well as promoting the production of antibodies. Further, IL- 6 is involved in the acute phase response to injury or infection, promoting inflammation and activating immune cells. Its function in hematopoiesis is to stimulate the production of blood cells in the bone marrow, including red blood cells, white blood cells, and platelets. IL-6 is further involved in the regulation of glucose metabolism and lipid metabolism and has been implicated in various neurological functions, including neuroprotection and neuroinflammation. Furthermore, abnormal IL-6 production has been associated with the development of a wide variety of systemic immune-mediated, chronic diseases, and even neoplasms.

IL-6 transmits its signals through a cell-surface type-I receptor complex, that consists of a ligand-binding glycoprotein termed as IL-6 receptor (IL-6R) and a signal-transducing component gpl30. When IL-6 binds to IL-6R, it induces a conformational change that enables the recruitment and assembly of gp!30. This leads to the formation of a high-affinity IL-6 receptor complex, which activates intracellular signaling pathways. The downstream signaling pathways activated by the IL-6 receptor complex depend on the cell type and context but can include the JAK-STAT pathway, the PI3K-Akt pathway, and the MAPK pathway.

Two forms of IL-6R are known: a membrane-bound form (mIL-6R) and a soluble form (sIL-6R). The membrane-bound form is found on the surface of cells and is responsible for the high-affinity binding of IL-6. The soluble form is generated by proteolytic cleavage of mIL-6R and can bind to IL-6, forming a complex with gpl30 and inducing intracellular signaling. The sIL-6R is capable of activating cells that do not express the membrane-bound form of IL-6R, expanding the range of cells that can respond to IL-6.

The IL-6 receptor is expressed on a wide range of cells, including immune cells, hepatocytes, adipocytes, and neurons.

Corona virus infection

Different corona virus outbreaks occurred in the last decades worldwide of which in particular three types of virus resulted in diseases with high mortality rates. The Severe Acute Respiratory Syndrome (SARS), the Middle East Respiratory Syndrome (MERS) and lately Coronavirus disease 2019 (COVID-19). The coronavirus responsible for these outbreaks where SARS-CoV, MERS-CoV and SARS-CoV-2, respectively.

COVID-19 typically presents with features of long non-symptomatic latency which might be a main contributing factor to a relatively high transmissibility compared to the other previously occurring deadly coronavirus infections, severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). COVID-19 patients typically present with flulike symptoms such as fever or signs of lower respiratory tract illness including dry cough and shortness of. With the progression of disease into a severe form, it often affects multiple organs’ functions including the lung, heart, liver, and coagulation system among others. As such, death is typically caused by respiratory failure and multiple organ dysfunctions similar to other viral pneumonia-induced sepsis. Sepsis and ARDS mostly occur in the second week upon disease onset.

Older age, underlying health conditions (e.g. cardiovascular issues) and compromised immune systems are important risk factors for the potential of developing a more severe form of disease onset and worse outcomes. The main comorbidities alongside COVID-19 that are associated with a high death rate are hypertension, diabetes and coronary heart disease. COVID-19 can be characterized by a dual play of viral inflammation and immune- mediated injury that may result in a “complement storm” event occurring in the progression of corona virus infection, in particular COVID-19.

Anti-C5a therapy for COVID-19 has been disclosed in W02021/190770 Al and recently received emergency use authorization (EUA) by the FDA. Likewise, the use of an IL- 6 receptor inhibitor (Tocilizumab; also known as Actemra) for the treatment of CO VID-19 also received an EUA and BLA from the FDA.

In the present invention the surprising effect of a combined anti-C5a and anti-IL-6 therapy of infectious pneumonia and/or infectious acute respiratory distress syndrome (ARDS) is disclosed.

Summary of the Invention

In a first aspect, the present invention provides an inhibitor of C5a activity for use in:

(i) combination with an inhibitor of IL-6 activity in the treatment of infectious pneumonia and/or infectious acute respiratory distress syndrome (ARDS); and/or

(ii) the treatment of infectious pneumonia and/or infectious acute respiratory distress syndrome (ARDS), wherein the patient is or has been treated with an inhibitor of IL-6 activity.

In a second aspect, the present invention provides an inhibitor of IL-6 activity for use in:

(i) combination with an inhibitor of C5a activity in the treatment of infectious pneumonia and/or infectious acute respiratory distress syndrome (ARDS); and/or

(ii) the treatment of infectious pneumonia and/or infectious acute respiratory distress syndrome (ARDS), wherein the patient is or has been treated with an inhibitor of C5a activity.

In a third aspect, the present invention provides a kit of parts comprising an inhibitor of C5a activity and an inhibitor of IL-6 activity.

List of Figures

In the following, the content of the figures comprised in this specification is described. In this context please also refer to the detailed description of the invention above and/or below.

Figure 1: IMP Administrations in Phase III refers to the administration schedule of the investigational medicinal product (IMP). The anti-C5a antibody IFX-1 (vilobelimab) was administered at a dose of 800mg on several days during the treatment period as indicated in figure 1. Figure 2: 60-day all-cause mortality for treatment with vilobelimab and any use of tocilizumab. Line 1 : Vilo + SOC with any use of tocilizumab; Line 2: Vilo + SOC without any use of tocilizumab; Line 3: Placebo + SOC with any use of tocvilizumab; Line 4: Placebo + SOC without any use of tocilizumab;

(SOC = Standard of care, Vilo = Vilobelimab)

Figure 3: 60-day all-cause mortality for treatment with vilobelimab and baseline use of tocilizumab. Line 1 : Vilo + SOC with baseline use of tocilizumab; Line 2: Vilo + SOC without baseline use of tocilizumab; Line 3: Placebo + SOC with any use of tocilizumab; Line 4: Placebo + SOC without baseline use of tocilizumab;

(SOC = Standard of care, Vilo = Vilobelimab)

Detailed Descriptions of the Invention

Before the present invention is described in detail below, it is to be understood that this invention is not limited to the particular methodology, protocols and reagents described herein as these may vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention which will be limited only by the appended claims. Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art.

Preferably, the terms used herein are defined as described in "A multilingual glossary of biotechnological terms: (IUPAC Recommendations)", Leuenberger, H.G.W, Nagel, B. and Klbl, H. eds. (1995), Helvetica Chimica Acta, CH-4010 Basel, Switzerland).

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. In the following passages, different aspects of the invention are defined in more detail. Each aspect so defined may be combined with any other aspect or aspects unless clearly indicated to the contrary. In particular, any feature indicated as being optional, preferred or advantageous may be combined with any other feature or features indicated as being optional, preferred or advantageous.

Several documents are cited throughout the text of this specification. Each of the documents cited herein (including all patents, patent applications, scientific publications, manufacturer's specifications, instructions etc.), whether supra or infra, is hereby incorporated by reference in its entirety. Nothing herein is to be construed as an admission that the invention is not entitled to antedate such disclosure by virtue of prior invention. Some of the documents cited herein are characterized as being “incorporated by reference ” . In the event of a conflict between the definitions or teachings of such incorporated references and definitions or teachings recited in the present specification, the text of the present specification takes precedence.

In the following, the elements of the present invention will be described. These elements are listed with specific embodiments; however, it should be understood that they may be combined in any manner and in any number to create additional embodiments. The variously described examples and preferred embodiments should not be construed to limit the present invention to only the explicitly described embodiments. This description should be understood to support and encompass embodiments which combine the explicitly described embodiments with any number of the disclosed and/or preferred elements. Furthermore, any permutations and combinations of all described elements in this application should be considered disclosed by the description of the present application unless the context indicates otherwise.

Definitions

In the following, some definitions of terms frequently used in this specification are provided. These terms will, in each instance of its use, in the remainder of the specification have the respectively defined meaning and preferred meanings.

As used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents, unless the content clearly dictates otherwise.

The term “about” when used in connection with a numerical value is meant to encompass numerical values within a range having a lower limit that is 5% smaller than the indicated numerical value and having an upper limit that is 5% larger than the indicated numerical value.

Sequences: All sequences referred to herein are disclosed in the attached sequence listing that, with its whole content and disclosure, is a part of this specification.

In the context of the present invention, C5a particularly refers to human C5a. Human C5a is a 74 amino acid peptide with the following amino acid sequence:

TLQKKIEEIA AKYKHSWKK CCYDGACVNN DETCEQRAAR ISLGPRCIKA FTECCWASQ LRANISHKDM QLGR (SEQ ID NO: 1).

The amino acid sequence of human C5 can be found under the accession number UniProtKB P01031 (C05 HUMAN). As used herein, the term “inhibitor of C5a activity” refers to any compound that in any way reduces the activity of C5a. This activity reduction can be achieved by directly or indirectly lowering the concentration of C5a, or by reducing the activity of C5a, or by preventing that C5a exerts its effects on one or more of its receptors (e.g. on C5aR or C5L2), or by reducing the concentration or activity of one or more receptors of C5a. Preferred inhibitors of C5a activity are antibodies specifically binding to hC5a.

In the context of the present invention, the expression “C5a receptor” refers to any potential C5a binding ligand on the cell surface, especially to any receptor protein to which C5a may bind and elicit a reaction on said receptor (e.g. activation or inhibition of the receptor). The term “C5a receptor” particularly encompasses the two receptors C5aR and C5L2. Alternative names for C5aR are C5aRl and CD88. An alternative name for C5L2 is C5aR2.

In the context of the present invention, Interleukin-6 (IL-6) particularly refers to human IL-6. Human IL-6 is an 212 amino acid peptide. The amino acid sequence of human IL-6 can be found under the accession number UniProtKB P05231 (IL6 HUMAN).

As used herein, the term “inhibitor of IL-6 activity” refers to any compound that in any way reduces the activity of IL-6. This activity reduction can be achieved by directly or indirectly lowering the concentration of IL-6, or by reducing the activity of IL-6, or by preventing that IL-6 exerts its effects on one or more of its receptors (e.g. on IL-6R), or by reducing the concentration or activity of one or more receptors of IL-6. Preferred inhibitors of IL-6 activity are antibodies specifically binding to IL-6 or IL-6R, preferably IL-6R.

In the context of the present invention, the expression “IL-6 receptor” refers to any potential IL-6 binding ligand, especially to any receptor protein to which IL-6 may bind and elicit a reaction on said receptor (e.g. activation or inhibition of the receptor). The term “IL-6 receptor” (IL-6R; sometimes referred to as CD 126) particularly encompasses the two receptor forms sIL-6R and mIL-6R.

As used herein, a first compound (e.g. an antibody or antigen-binding fragment thereof) is considered to “bind” to a second compound (e.g. a target protein), if it has a dissociation constant Ka to said second compound of 1 mM or less, preferably 100 pM or less, preferably 50 pM or less, preferably 30 pM or less, preferably 20 pM or less, preferably 10 pM or less, preferably 5 pM or less, more preferably 1 pM or less, more preferably 900 nM or less, more preferably 800 nM or less, more preferably 700 nM or less, more preferably 600 nM or less, more preferably 500 nM or less, more preferably 400 nM or less, more preferably 300 nM or less, more preferably 200 nM or less, even more preferably 100 nM or less, even more preferably 90 nM or less, even more preferably 80 nM or less, even more preferably 70 nM or less, even more preferably 60 nM or less, even more preferably 50 nM or less, even more preferably 40 nM or less, even more preferably 30 nM or less, even more preferably 20 nM or less, and even more preferably 10 nM or less.

The term “binding” according to the invention preferably relates to a specific binding. “Specific binding” means that a compound (e.g an antibody or antigen-binding fragment thereof) binds stronger to a target such as an epitope for which it is specific compared to the binding to another target. A compound binds stronger to a first target compared to a second target, if it binds to the first target with a dissociation constant (Ka) which is lower than the dissociation constant for the second target. Preferably the dissociation constant (Ka) for the target to which the compound binds specifically is more than 10-fold, preferably more than 20- fold, more preferably more than 50-fold, even more preferably more than 100-fold, 200-fold, 500-fold or 1000-fold lower than the dissociation constant (Ka) for the target to which the compound does not bind specifically.

As used herein, the term “Ka” (usually measured in “mol/L”, sometimes abbreviated as “M”) is intended to refer to the dissociation equilibrium constant of the particular interaction between a binding moiety (e.g. an antibody or antigen-binding fragment thereof) and a target molecule (e.g. an antigen or epitope thereof).

Methods for determining binding affinities of compounds, i.e. for determining the dissociation constant Ka, are known to a person of ordinary skill in the art and can be selected for instance from the following methods known in the art: Surface Plasmon Resonance (SPR) based technology, Bio-layer interferometry (BLI), enzyme-linked immunosorbent assay (ELISA), flow cytometry, isothermal titration calorimetry (ITC), analytical ultracentrifugation, radioimmunoassay (RIA or IRMA) and enhanced chemiluminescence (ECL). Typically, the dissociation constant Ka is determined at 20°C, 25°C, 30°C, or 37°C. If not specifically indicated otherwise, the Ka values recited herein are determined by surface plasmon resonance spectroscopy (Biacore™) at room temperature (25°C).

Typically, antibodies and antigen-binding fragments thereof according to the invention bind with a sufficient binding affinity to their target, for example, with a Kd value of between 500 nM-1 pM, i.e. 500 nM, 450 nM, 400nM, 350 nM, 300nM, 250 nM, 200nM, 150 nM, lOOnM, 50 nM, 10 nM, 1 nM, 900 pM, 800 pM, 700 pM, 600 pM, 500 pM, 400 pM, 300 pM, 200 pM, 100 pM, 50 pM, IpM.

An “epitope”, also known as antigenic determinant, is the part of a macromolecule that is recognized by the immune system, specifically by antibodies, B cells, or T cells. As used herein, an “epitope” is the part of a macromolecule capable of binding to a compound (e.g. an antibody or antigen-binding fragment thereof) as described herein. In this context, the term “binding” preferably relates to a specific binding. Epitopes usually consist of chemically active surface groupings of molecules such as amino acids or sugar side chains and usually have specific three-dimensional structural characteristics, as well as specific charge characteristics. Conformational and non-conformational epitopes can be distinguished in that the binding to the former but not the latter is lost in the presence of denaturing solvents.

A “paratope” is the part of an antibody that binds to the epitope.

The term “antibody” typically refers to a glycoprotein comprising at least two heavy (H) chains and two light (L) chains inter-connected by disulfide bonds, or an antigen-binding portion thereof. The term “antibody” also includes all recombinant forms of antibodies, in particular of the antibodies described herein, e.g. antibodies expressed in prokaryotes, unglycosylated antibodies, antibodies expressed in eukaryotes (e.g. CHO cells), glycosylated antibodies, and any antigen-binding antibody fragments and derivatives as described below. Each heavy chain is comprised of a heavy chain variable region (abbreviated herein as VH or VH) and a heavy chain constant region. Each light chain is comprised of a light chain variable region (abbreviated herein as VL or VL) and a light chain constant region. The VH and VL regions can be further subdivided into regions of hypervariability, termed complementarity determining regions (CDR), interspersed with regions that are more conserved, termed framework regions (FR). Each VH and VL is composed of three CDRs and four FRs, arranged from amino-terminus to carboxy-terminus in the following order: FR1, CDR1, FR2, CDR2, FR3, CDR3, FR4. The variable regions of the heavy and light chains contain a binding domain that interacts with an antigen. The constant regions of the antibodies may mediate the binding of the immunoglobulin to host tissues or factors, including various cells of the immune system (e.g., effector cells) and the first component (Clq) of the classical complement system.

The term "CDR" or "complementarity determining region" refers to the non-contiguous antigen binding sites found within the variable region of both heavy and light chain polypeptides (sometimes referred to as LCDR or HCDR). CDRs have been described by Kabat et al., J. Biol. Chem. 252:6609-6616 (1977); Kabat et al., U.S. Dept, of Health and Human Services, "Sequences of proteins of immunological interest" (1991) (also referred to herein as Kabat 1991); by Chothia et al., J. Mol. Biol. 196:901-917 (1987) (also referred to herein as Chothia 1987); and MacCallum et al., J. Mol. Biol. 262:732-745 (1996), where the definitions include overlapping or subsets of amino acid residues when compared against each other. Nevertheless, application of either definition to refer to a CDR of an antibody or grafted antibodies or variants thereof is intended to be within the scope of the term as defined and used herein. The CDRs listed in Table 1 were defined in accordance with Kabat 1991.

The term “antigen-binding fragment” of an antibody (or simply “binding portion”), as used herein, refers to one or more fragments of an antibody that retain the ability to specifically bind to an antigen. It has been shown that the antigen-binding function of an antibody can be performed by fragments of a full-length antibody. Examples of binding fragments encompassed within the term “antigen-binding portion” of an antibody include (i) Fab fragments, monovalent fragments consisting of the VL, VH, CL and CH domains; (ii) F(ab')2 fragments, bivalent fragments comprising two Fab fragments linked by a disulfide bridge at the hinge region; (iii) Fd fragments consisting of the VH and CH domains; (iv) Fv fragments consisting of the VL and VH domains of a single arm of an antibody, (v) dAb fragments (Ward et al., (1989) Nature 341 : 544-546), which consist of a VH domain; (vi) isolated complementarity determining regions (CDR), and (vii) combinations of two or more isolated CDRs which may optionally be joined by a synthetic linker. Furthermore, although the two domains of the Fv fragment, VL and VH, are coded for by separate genes, they can be joined, using recombinant methods, by a synthetic linker that enables them to be made as a single protein chain in which the VL and VH regions pair to form monovalent molecules (known as single chain Fv (scFv); see e.g., Bird et al. (1988) Science 242: 423-426; and Huston et al. (1988) Proc. Natl. Acad. Sci. USA 85: 5879- 5883). Such single chain antibodies are also intended to be encompassed within the term “antigen-binding fragment” of an antibody. A further example is a binding-domain immunoglobulin fusion protein comprising (i) a binding domain polypeptide that is fused to an immunoglobulin hinge region polypeptide, (ii) an immunoglobulin heavy chain CH2 constant region fused to the hinge region, and (iii) an immunoglobulin heavy chain CH3 constant region fused to the CH2 constant region. The binding domain polypeptide can be a heavy chain variable region or a light chain variable region. The binding-domain immunoglobulin fusion proteins are further disclosed in US 2003/0118592 and US 2003/0133939. These antibody fragments are obtained using conventional techniques known to those skilled in the art, and the fragments are screened for utility in the same manner as are intact antibodies. Further examples of “antigen-binding fragments” are so-called microantibodies, which are derived from single CDRs. For example, Heap et al., 2005, describe a 17 amino acid residue microantibody derived from the heavy chain CDR3 of an antibody directed against the gpl20 envelope glycoprotein of HIV-1 (Heap C.J. et al. (2005); J. Gen. Virol. 86: 1791-1800). Other examples include small antibody mimetics comprising two or more CDR regions that are fused to each other, preferably by cognate framework regions. Such a small antibody mimetic comprising VH CDR1 and VL CDR3 linked by the cognate VH FR2 has been described by Qiu et al., 2007 (Qiu X.Q. et al. (2007); Nature biotechnology 25(8):921-929).

Thus, the term “antibody or antigen-binding fragment thereof’, as used herein, refers to immunoglobulin molecules and immunologically active portions of immunoglobulin molecules, i.e. molecules that contain an antigen-binding site that immunospecifically binds an antigen. Also comprised are immunoglobulin-like proteins that are selected through techniques including, for example, phage display to specifically bind to a target molecule or target epitope. The immunoglobulin molecules of the invention can be of any type (e.g., IgG, IgE, IgM, IgD, IgA and IgY), class (e.g., IgGl, IgG2, preferably IgG2a and IgG2b, IgG3, IgG4, IgAl and IgA2) or subclass of immunoglobulin molecule.

Antibodies and antigen-binding fragments thereof usable in the invention may be from any animal origin including birds and mammals. Preferably, the antibodies or fragments are from human, chimpanzee, rodent (e.g. mouse, rat, guinea pig, or rabbit), chicken, turkey, pig, sheep, goat, camel, cow, horse, donkey, cat, or dog origin. It is particularly preferred that the antibodies are of human or murine origin. Antibodies of the invention also include chimeric molecules in which an antibody constant region derived from one species, preferably human, is combined with the antigen-binding site derived from another species, e.g. mouse. Moreover, antibodies of the invention include humanized molecules in which the antigen-binding sites of an antibody derived from a non-human species (e.g. from mouse) are combined with constant and framework regions of human origin.

As exemplified herein, antibodies of the invention can be obtained directly from hybridomas which express the antibody, or can be cloned and recombinantly expressed in a host cell (e.g., a CHO cell, or a lymphocytic cell). Further examples of host cells are microorganisms, such as E. coli, and fungi, such as yeast. Alternatively, they can be produced recombinantly in a transgenic non-human animal or plant.

The term “chimeric antibody” refers to those antibodies wherein one portion of each of the amino acid sequences of heavy and light chains is homologous to corresponding sequences in antibodies derived from a particular species or belonging to a particular class, while the remaining segment of the chain is homologous to corresponding sequences in another species or class. Typically the variable region of both light and heavy chains mimics the variable regions of antibodies derived from one species of mammals, while the constant portions are homologous to sequences of antibodies derived from another. One clear advantage to such chimeric forms is that the variable region can conveniently be derived from presently known sources using readily available B-cells or hybridomas from non-human host organisms in combination with constant regions derived from, for example, human cell preparations. While the variable region has the advantage of ease of preparation and the specificity is not affected by the source, the constant region being human is less likely to elicit an immune response from a human subject when the antibodies are injected than would the constant region from a nonhuman source. However, the definition is not limited to this particular example.

The term “humanized antibody” refers to a molecule having an antigen-binding site that is substantially derived from an immunoglobulin from a non-human species, wherein the remaining immunoglobulin structure of the molecule is based upon the structure and/or sequence of a human immunoglobulin. The antigen-binding site may either comprise complete variable domains fused onto constant domains or only the complementarity determining regions (CDR) grafted onto appropriate framework regions in the variable domains. Antigen-binding sites may be wild-type or modified by one or more amino acid substitutions, e.g. modified to resemble human immunoglobulins more closely. Some forms of humanized antibodies preserve all CDR sequences (for example a humanized mouse antibody which contains all six CDRs from the mouse antibody). Other forms have one or more CDRs which are altered with respect to the original antibody.

Different methods for humanizing antibodies are known to the skilled person, as reviewed by Almagro & Fransson, 2008, Frontiers in Bioscience, 13: 1619-1633, the content of which is herein incorporated by reference in its entirety. The review article by Almagro & Fransson is briefly summarized in US 2012/0231008 Al which is the national stage entry of international patent application WO 2011/063980 Al. The contents of US 2012/0231008 Al and WO 2011/063980 Al are herein incorporated by reference in their entirety.

As used herein, “human antibodies” include antibodies having variable and constant regions derived from human germline immunoglobulin sequences. The human antibodies of the invention may include amino acid residues not encoded by human germline immunoglobulin sequences (e.g., mutations introduced by random or site-specific mutagenesis in vitro or by somatic mutation in vivo). Human antibodies of the invention include antibodies isolated from human immunoglobulin libraries or from animals transgenic for one or more human immunoglobulin and that do not express endogenous immunoglobulins, as described for example in U.S. Patent No. 5,939,598 by Kucherlapati & Jakobovits.

The term “monoclonal antibody” as used herein refers to a preparation of antibody molecules of single molecular composition. A monoclonal antibody displays a single binding specificity and affinity for a particular epitope. In one embodiment, the monoclonal antibodies are produced by a hybridoma which includes a B cell obtained from a non-human animal, e.g. mouse, fused to an immortalized cell.

The term “recombinant antibody”, as used herein, includes all antibodies that are prepared, expressed, created or isolated by recombinant means, such as (a) antibodies isolated from an animal (e.g., a mouse) that is transgenic or transchromosomal with respect to the immunoglobulin genes or a hybridoma prepared therefrom, (b) antibodies isolated from a host cell transformed to express the antibody, e.g. from a transfectoma, (c) antibodies isolated from a recombinant, combinatorial antibody library, and (d) antibodies prepared, expressed, created or isolated by any other means that involve splicing of immunoglobulin gene sequences to other DNA sequences.

The term “transfectoma”, as used herein, includes recombinant eukaryotic host cells expressing an antibody, such as CHO cells, NS/0 cells, HEK293 cells, HEK293T cells, plant cells, or fungi, including yeast cells.

As used herein, a “heterologous antibody” is defined in relation to a transgenic organism producing such an antibody. This term refers to an antibody having an amino acid sequence or an encoding nucleic acid sequence corresponding to that found in an organism not consisting of the transgenic organism, and being generally derived from a species other than the transgenic organism.

As used herein, a “heterohybrid antibody” refers to an antibody having light and heavy chains of different organismal origins. For example, an antibody having a human heavy chain associated with a murine light chain is a heterohybrid antibody.

Thus, “antibodies and antigen-binding fragments thereof’ suitable for use in the present invention include, but are not limited to, polyclonal, monoclonal, monovalent, bispecific, heteroconjugate, multispecific, recombinant, heterologous, heterohybrid, chimeric, humanized (in particular CDR-grafted), deimmunized, or human antibodies, Fab fragments, Fab' fragments, F(ab')2 fragments, fragments produced by a Fab expression library, Fd, Fv, disulfide- linked Fvs (dsFv), single chain antibodies (e.g. scFv), diabodies or tetrabodies (Holliger P. et al. (1993) Proc. Natl. Acad. Sci. U.S.A. 90(14), 6444-6448), nanobodies (also known as single domain antibodies), anti-idiotypic (anti-Id) antibodies (including, e.g., anti-Id antibodies to antibodies described herein), and epitope-binding fragments of any of the above.

The antibodies described herein are preferably isolated. An “isolated antibody” as used herein, is intended to refer to an antibody which is substantially free of other antibodies having different antigenic specificities (e.g., an isolated antibody that specifically binds to C5a is substantially free of antibodies that specifically bind antigens other than C5a). An isolated antibody that specifically binds to an epitope, isoform or variant of human C5a may, however, have cross-reactivity to other related antigens, e.g. from other species (e.g. C5a species homologs, such as rat C5a). Moreover, an isolated antibody may be substantially free of other cellular material and/or chemicals. In one embodiment of the invention, a combination of “isolated” monoclonal antibodies relates to antibodies having different specificities and being combined in a well-defined composition.

The term “naturally occurring”, as used herein, as applied to an object refers to the fact that an object can be found in nature. For example, a polypeptide or polynucleotide sequence that is present in an organism (including viruses) that can be isolated from a source in nature and which has not been intentionally modified by man in the laboratory is naturally occurring.

Vilobelimab (sometimes referred to as IFX-1; InflaRx GmbH, Germany) is an antibody specifically binding to C5a. The CDR sequences and FR sequences of IFX-1 are disclosed in WO 2011/063980 Al (in Table 4 on page 51), the content of which is hereby incorporated by reference in its entirety. The affinity (Ka) and blocking activity is disclosed in WO 2011/063980 Al (in Table 3 on pages 49-50), the content of which is hereby incorporated by reference in its entirety.

BNJ364, BNJ367, BNJ371, BNJ378, BNJ366, BNJ369, BNJ381 and BNJ383 are antibodies specifically binding to C5a. The CDR sequences and FR sequences of these antibodies are disclosed in WO 2011/137395 Al (in Table 2 starting on page 55), the content of which is incorporated by reference in its entirety.

MEDI-7814 (Medlmmune) is a recombinant humanized anti-C5a antibody. The crystal structure of the human C5a in complex with MEDI7814 is available in the RCSB Protein Data Bank under 4UU9 (DOI: 10.2210/pdb4uu9/pdb).

ALXN-1007 (Alexion) is a humanized anti-C5a antibody.

Tocilizumab is a monoclonal antibody specifically binding to the IL-6 receptor (IL-6R). Tocilizumab (brand name Actemra) binds to soluble as well as membrane bound IL-6 receptor (sIL-6R and mIL-6R respectively). Tocilizumab is effective in blocking downstream IL-6 signalling.

Sarilumab (brand name Kevzara) is a further antibody binding to IL-6R that is suitable to exercise the invention. Sarilumab is a human monoclonal antibody binding to the IL-6 receptor.

Levilimab is a fully human monoclonal antibody acting against the interleukin-6 receptor (IL-6R), developed by Biocad, for the treatment of rheumatoid arthritis. Levilimab targets membrane bound and soluble IL-6 receptor. Vobarilizumab (synonym ALX-0061) is an high affinity anti-IL-6R bispecific nanobody further targeting albumin to extend half-life.

Siltuximab (brand name Sylvant) is a chimeric monoclonal antibody that binds to interleukin-6 (IL-6), preventing binding to soluble and membrane bound interleukin-6 receptors. Siltuximab is FDA-approved for treatment of patients with idiopathic multicentric Castleman’s disease (iMCD) who do not have human immunodeficiency virus (HIV) or human herpesvirus-8 (HHV-8).

Sirukumab is a human monoclonal antibody specifically binding to IL-6. Sirukumab is under development for the treatment of rheumatoid arthritis.

Olokizumab is a humanized monoclonal antibody specifically binding to IL-6. Olokizumab has been tested for treatment of rheumatoid arthritis and has been used as an emergency experimental cytokine storm COVID-19 treatment.

Elsilimomab is a monoclonal antibody that targets and blocks IL-6. Elsilimomab has been under development for treatment of lymphoma and myeloma.

Clazakizumab is a humanized monoclonal antibody directed against IL-6. Clazakizumab has been under development for treatment of psoriatic arthritis.

PF-4236921 (sometimes referred to as PF-04236921) is an anti-IL-6 monoclonal antibody that has been under development for the treatment of rheumatoid arthritis, systemic lupus erythematosus and Crohn's disease.

EBL031 (sometimes referred to as RG-6179) is a humanised monoclonal antibody that specifically binds to IL-6.

As used herein, a “patient” means any mammal or bird who may benefit from a treatment with the compound described herein (i.e. with an inhibitor of C5a activity described herein). Preferably, a “patient” is selected from the group consisting of laboratory animals (e.g. mouse or rat), domestic animals (including e.g. guinea pig, rabbit, chicken, turkey, pig, sheep, goat, camel, cow, horse, donkey, cat, or dog), or primates including chimpanzees and human beings. It is particularly preferred that the “patient” is a human being.

As used herein, "treat", "treating" or “treatment” of a disease or disorder means accomplishing one or more of the following: (a) reducing the severity and/or duration of the disorder; (b) limiting or preventing development of symptoms characteristic of the disorder(s) being treated; (c) inhibiting worsening of symptoms characteristic of the disorder(s) being treated; (d) limiting or preventing recurrence of the disorder(s) in patients that have previously had the disorder(s); and (e) limiting or preventing recurrence of symptoms in patients that were previously symptomatic for the disorder(s). As used herein, “prevent”, “preventing”, “prevention”, or “prophylaxis” of a disease or disorder means preventing that a disorder occurs in subject.

An “effective amount” is an amount of a therapeutic agent sufficient to achieve the intended purpose. The effective amount of a given therapeutic agent will vary with factors such as the nature of the agent, the route of administration, the size and species of the animal to receive the therapeutic agent, and the purpose of the administration. The effective amount in each individual case may be determined empirically by a skilled artisan according to established methods in the art.

The term “active agent” as used herein, refers to any therapeutic activity an agent may exhibit.

“Pharmaceutically acceptable” means approved by a regulatory agency of the Federal or a state government or listed in the U.S. Pharmacopeia or other generally recognized pharmacopeia for use in animals, and more particularly in humans.

The term “carrier”, as used herein, refers to a diluent, adjuvant, excipient, or vehicle with which the therapeutic agent is administered. Such pharmaceutical carriers can be sterile liquids, such as saline solutions in water and oils, including those of petroleum, animal, vegetable or synthetic origin, such as peanut oil, soybean oil, mineral oil, sesame oil and the like. A saline solution is a preferred carrier when the pharmaceutical composition is administered intravenously. Saline solutions and aqueous dextrose and glycerol solutions can also be employed as liquid carriers, particularly for injectable solutions. Suitable pharmaceutical excipients include starch, glucose, lactose, sucrose, gelatin, malt, rice, flour, chalk, silica gel, sodium stearate, glycerol monostearate, talc, sodium chloride, dried skim milk, glycerol, propylene, glycol, water, ethanol and the like. The composition, if desired, can also contain minor amounts of wetting or emulsifying agents, or pH buffering agents. These compositions can take the form of solutions, suspensions, emulsions, tablets, pills, capsules, powders, sustained-release formulations and the like. The composition can be formulated as a suppository, with traditional binders and carriers such as triglycerides. The compounds of the invention can be formulated as neutral or salt forms. Pharmaceutically acceptable salts include those formed with free amino groups such as those derived from hydrochloric, phosphoric, acetic, oxalic, tartaric acids, etc., and those formed with free carboxyl groups such as those derived from sodium, potassium, ammonium, calcium, ferric hydroxides, isopropylamine, triethylamine, 2-ethylamino ethanol, histidine, procaine, etc. Examples of suitable pharmaceutical carriers are described in "Remington's Pharmaceutical Sciences" by E. W. Martin. Such compositions will contain a therapeutically effective amount of the compound, preferably in purified form, together with a suitable amount of carrier so as to provide the form for proper administration to the patient. The formulation should suit the mode of administration.

Embodiments

In the following different aspects of the invention are defined in more detail. Each aspect so defined may be combined with any other aspect or aspects unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous.

In combination treatment the inhibitor of C5a activity and the inhibitor of IL-6 activity are preferably administered within the half-life of the other inhibitor. For example, if an inhibitor of C5a activity with a half-life of about 4 days and an inhibitor of IL-6 activity with a half-life of about 13 days is used, then the inhibitor of IL-6 activity would be administered within about 3 days after the administration of the inhibitor of C5a activity or if the inhibitor of IL-6 activity is administered first, the inhibitor of C5a activity is administered within 13 days after the inhibitor of IL-6 activity. Thus an overlap between the action of both inhibitors should exist in combination treatment.

In a preferred embodiment the inhibitor of C5a activity and the inhibitor of IL-6 activity are preferably administered within 1-5 (i.e. 1, 2, 3, 4 or 5) half-lives of the other inhibitor.

In a preferred embodiment of the first aspect of the invention the inhibitor of C5a activity and the inhibitor of IL-6 activity are administered on the same day.

In a preferred embodiment of the first aspect of the invention the inhibitor of IL-6 activity is administered within 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14 days prior or after the administration of the inhibitor of C5a activity.

In a preferred embodiment of the first aspect of the invention the inhibitor of C5a activity is administered within 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14 days prior or after the administration of the inhibitor of IL-6 activity.

The patients benefiting most from the use of the inhibitor of C5a activity in the treatment of infectious pneumonia and/or infectious acute respiratory distress syndrome (ARDS) are patients that are or have been treated with an inhibitor of IL-6 activity. In a preferred embodiment the inhibitor of IL-6 activity is or has been administered to the patient within a time-window so that there is an overlap between the action of the inhibitor of IL-6 activity and the inhibitor of C5a activity, at least with regard to the administration of the first dose of the inhibitor of C5a activity.

In combination treatment the inhibitor of IL-6 activity and the inhibitor of C5a activity are preferably administered within the half-life of the other inhibitor. For example, if an inhibitor of IL-6 activity with a half-life of about 13 days and an inhibitor of C5a activity with a half-life of about 4 days is used, then the inhibitor of IL-6 activity would be administered within about 4 days after the administration of the inhibitor of C5a activity or if the inhibitor of IL-6 activity is administered first, the inhibitor of C5a activity is administered within 13 days after the inhibitor of IL-6 activity. Thus an overlap between the action of both inhibitors should exist in combination treatment.

In a preferred embodiment of the first aspect of the invention the inhibitor of IL-6 activity and the inhibitor of C5a activity are administered on the same day.

In a preferred embodiment of the first aspect of the invention the inhibitor of IL-6 activity is administered within 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14 days after the administration of the inhibitor of C5a activity.

In a preferred embodiment of the first aspect of the invention the inhibitor of C5a activity is administered within 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14 days after the administration of the inhibitor of IL-6 activity.

The patients benefiting most from the use of the inhibitor of IL-6 activity in the treatment of infectious pneumonia and/or infectious acute respiratory distress syndrome (ARDS) are patients that are or have been treated with an inhibitor of C5a activity. In a preferred embodiment the inhibitor of C5a activity is or has been administered to the patient within a time-window so that there is an overlap between the action of the inhibitor of IL-6 activity and the inhibitor of C5a activity, at least with regard to the administration of the first dose of the inhibitor of IL-6 activity. Inhibitors of IL-6 activity

In a preferred embodiment of all aspects of the present invention, the inhibitor of IL-6 activity specifically binds to IL-6 or the IL-6 receptor. In a preferred embodiment the inhibitor of IL-6 activity comprises a protein ligand. In a preferred embodiment the inhibitor of IL-6 activity is a protein ligand. In a preferred embodiment the inhibitor of IL-6 activity is an antibody or antigen binding fragment thereof specifically binding to the IL-6 receptor. In a preferred embodiment the inhibitor of IL-6 activity is an antibody or antigen binding fragment thereof specifically binding to IL-6.

In a preferred embodiment according to all aspects of the invention the inhibitor of IL- 6 activity is specifically binding to IL-6R, preferably selected from Tocilizumab, Sarilumab, Levilimab and Vobarilizumab. Preferably the inhibitor of IL-6R is Tocilizumab.

In a preferred embodiment according to all aspects of the invention the inhibitor of IL- 6 activity is specifically binding to IL-6R, preferably selected from Siltuximab, Sirukumab, Olokizumab, Elsilimomab, Clazakinumab, PF-423691 and EBI-031.

Inhibitors of C5a activity

In a preferred embodiment of all aspects of the invention, the inhibitor of C5a activity binds specifically to C5a or to the C5a receptor (C5aR). In a preferred embodiment, the inhibitor of C5a activity binds specifically to C5a. In a preferred embodiment, the inhibitor of C5a activity binds specifically to C5aR. In a preferred embodiment the inhibitor of C5a activity comprises a protein ligand specifically binding to C5a or the C5aR. In a preferred embodiment the inhibitor of C5a activity comprises a protein ligand specifically binding to C5a. In a preferred embodiment the inhibitor of C5a activity comprises a protein ligand specifically binding to C5aR.

In a preferred embodiment the inhibitor of C5a activity, is a small molecule C5aR antagonist. Suitable small molecule C5aR antagonists are known in the art and can inter alia be found in WO 2020/182384 Al, which is incorporated by reference herein. Methods for preparing the small molecule C5aR antagonists can be found in WO 2020/182384 AL

In a preferred embodiment the inhibitor of C5a activity is a small molecule having the general formula (I)

and pharmaceutically acceptable salts, hydrates and rotamers thereof; wherein

C¹ is selected from the group consisting of aryl and heteroaryl, wherein the heteroaryl group has from 1-3 heteroatoms as ring members selected from N, O and S; and wherein said aryl and heteroaryl groups are optionally substituted with from 1 to 3 R¹ substituents;

C² is selected from the group consisting of aryl and heteroaryl, wherein the heteroaryl group has from 1-3 heteroatoms as ring members selected from N, O and S; and wherein said aryl and heteroaryl groups are optionally substituted with from 1 to 3 R² substituents;

C³ is selected from the group consisting of Ci-8 alkyl or heteroalkyl, C3-8 cycloalkyl, C3-8 cycloalkyl-Ci-4 alkyl, aryl, aryl-Ci-4 alkyl, heteroaryl, heteroaryl-Ci-4 alkyl, heterocycloalkyl or heterocycloalkyl-Ci-4 alkyl, wherein the heteroalkyl group has from 1-3 heteroatoms selected from N, O and S, wherein the heterocycloalkyl group or portion has from 1-3 heteroatoms selected from N, O and S, and wherein the heteroaryl group has from 1-3 heteroatoms as ring members selected from N, O and S, and each C³ is optionally substituted with from 1 to 3 R³ substituents; each R¹ is independently selected from the group consisting of halogen, — CN, -R^c, — CO₂R^a, — CONR^aR^b, — C(O)R^a, — OC(O)NR^aR^b, — NR^bC(O)R^a, — NR^bC(O)₂R^c, — NR^a— C(O)NR^aR^b, — NR^aC(O)NR^aR^b, — NR^aR^b, — OR^a, and — S(O)₂NR^aR^b; wherein each R^a and R^b is independently selected from hydrogen, C1-8 alkyl, and C1-8 haloalkyl, or when attached to the same nitrogen atom can be combined with the nitrogen atom to form a five or six-membered ring having from 0 to 2 additional heteroatoms as ring members selected from N, O or S, and is optionally substituted with one or two oxo; each R^c is independently selected from the group consisting of C1-8 alkyl or heteroalkyl, C1-8 haloalkyl, C3-6 cycloalkyl, heterocycloalkyl, aryl and heteroaryl, and wherein the aliphatic and/or cyclic portions of R^a, R^b and R^c are optionally further substituted with from one to three halogen, hydroxy, methyl, amino, alkylamino and dialkylamino groups; and optionally when two R¹ substituents are on adjacent atoms, are combined to form a fused five or six-membered carbocyclic or heterocyclic ring; each R² is independently selected from the group consisting of halogen, — CN, — NO₂, — R^f, — CO₂R^d, — CONR^dR^e, — C(O)R^d, — OC(O)NR^dR^e, — NR^eC(O)R^d, — NR^eC(O)₂R^f, — NR^dC(O)NR^dR^e, — NR^dR^e, — OR^d, and — S(O)₂NR^dR^e; wherein each R^d and R^e is independently selected from hydrogen, C1-8 alkyl, and C1-8 haloalkyl, or when attached to the same nitrogen atom can be combined with the nitrogen atom to form a five or sixmembered ring having from 0 to 2 additional heteroatoms as ring members selected from N, O or S, and is optionally substituted with one or two oxo; each R^f is independently selected from the group consisting of C1-8 alkyl or heteroalkyl, C1-8 haloalkyl, C3-6 cycloalkyl, heterocycloalkyl, aryl and heteroaryl, and wherein the aliphatic and/or cyclic portions of R^d, R^e and R^fare optionally further substituted with from one to three halogen, hydroxy, methyl, amino, alkylamino and dialkylamino groups, and optionally when two R² groups are on adjacent atoms, they are combined to form a five- or six-membered ring; each R³ is independently selected from the group consisting of halogen, — CN, — R¹, — CO₂R^g, — CONR^gR^h, — C(O)R^g, — C(O)R', — OC(O)NR^gR^h, — NR^hC(O)R^g, — NR^hCO₂Rⁱ, — NRSQOjNRSR¹¹, — NR^gR^h, — OR^g, — OR^j, S(O)₂NR^gR^h, — X⁴— R^j, — NH— X⁴— R>,

— O— X⁴— R^j, — X⁴— NR^gR^h, — X⁴— NHR>, — X⁴— CONR^gR^h, — X⁴— NR^hC(O)R^g, — X⁴— CO₂R^g, — O— X⁴— CO₂R^g, — NH— X⁴— CO₂R^g, — X⁴— NR^hCO₂Rⁱ, — O— X⁴ — NR¹¹CO₂R^I, — NHR¹ and — NHCH2R¹, wherein X⁴ is a C1-4 alkylene; each R^g and R^h is independently selected from hydrogen, C1-8 alkyl or heteroalkyl, C3-6 cycloalkyl and C1-8 haloalkyl, or when attached to the same nitrogen atom can be combined with the nitrogen atom to form a four-, five- or six-membered ring having from 0 to 2 additional heteroatoms as ring members selected from N, O or S and is optionally substituted with one or two oxo; each R¹ is independently selected from the group consisting of C1-8 alkyl or heteroalkyl, C1-8 haloalkyl, C3-6 cycloalkyl, heterocycloalkyl, aryl and heteroaryl; and each R> is selected from the group consisting of C3-6 cycloalkyl, imidazolyl, pyrimidinyl, pyrrolinyl, pyrrolyl, piperidinyl, morpholinyl, tetrahydrofuranyl, tetrahydropyranyl, and S,S-dioxo-tetrahydrothiopyranyl, and wherein the aliphatic and/or cyclic portions of R^g, R^h, R¹ and R¹ are optionally further substituted with from one to three halogen, methyl, CF3, hydroxy, C1-4 alkoxy, C1-4 alkoxy-Ci-4 alkyl, — C(O)O — C1-8 alkyl, amino, alkylamino and dialkylamino groups, and optionally when two R³ groups are on adjacent atoms, they are combined to form a five- or six-membered ring;

X is hydrogen or CH3; and R⁸ and R⁹ are independently from each other selected from the group consisting of hydrogen, halogen, Ci-Cs alkyl, Ci-Cs haloalkyl, and Ci-Cs alkoxy or R⁸ and R⁹ are combined to form a fused saturated or unsaturated mono- or multi-ring carbocycle in which one or more of the ring carbon atoms may be replaced independently from each other by N, S, or O, with the proviso that at least one of R⁸ and R⁹ is not hydrogen.

In a preferred embodiment the inhibitor of C5a activity is a small molecule C5aR antagonist having the general formula (I) as indicated above and wherein R⁸ and/or R⁹ is hydrogen.

In a preferred embodiment the inhibitor of C5a activity is selected from:

INF 004 : (2R,3 S)-2-(4-(cyclopentylamino)phenyl)- 1 -(2-fluoro-6-methylbenzoyl)-

N-(4-methyl-3-(trifluoromethyl)phenyl)-l,2,3,4-tetrahydroquinoline-3-carboxamide

INF011 : (2R,3S)-l-(2-fluoro-6-methylbenzoyl)-N-(4-methyl-3-

(trifluoromethyl)phenyl)-2-(4-((tetrahydro-2H-pyran-4-yl)amino)phenyl)-l,2,3,4- tetrahydroquinoline-3-carboxamide

INFO 14: (2R,3S)-l-(2-chlorobenzoyl)-2-(4-(cyclopentylamino)phenyl)-N-(4-

(hydroxymethyl)-3 -(tri fluoromethyl Jphenyl)- 1,2, 3, 4-tetrahydroquinoline-3 -carboxamide

INFO 15 : (2R,3 S)-2-(4-(cyclopentylamino)phenyl)- 1 -(2-fluoro-6-methylbenzoyl)-

N-(4-(hydroxymethyl)-3 -(tri fluoromethyl (phenyl)- 1,2, 3, 4-tetrahydroquinoline-3 -carboxamide

INF022: (2R,3S)-2-(4-(cyclopentylamino)phenyl)-6-fluoro-l-(2-fluoro-6- methylbenzoyl)-N-(4-methyl-3-(tri fluoromethyl)phenyl)- 1,2,3, 4-tetrahydroquinoline-3- carb oxami de

INF023: (2R,3S)-2-(4-(cyclopentylamino)phenyl)-l-(2-fluoro-6-methylbenzoyl)-

6-methyl-N-(4-methyl-3 -(tri fluoromethyl)phenyl)- 1,2, 3, 4-tetrahydroquinoline-3 -carboxamide

INF024: (2R,3S)-2-(4-(cyclopentylamino)phenyl)-l-(2-fluoro-6-methylbenzoyl)-

6-methoxy-N-(4-methyl-3 -(tri fluoromethyl)phenyl)- 1,2,3, 4-tetrahydroquinoline-3 - carboxamide

INF025: (2R,3S)-2-(4-(cyclopentylamino)phenyl)-6,7-difluoro-l-(2-fluoro-6- methylbenzoyl)-N-(4-methyl-3-(tri fluoromethyl)phenyl)- 1,2,3, 4-tetrahydroquinoline-3- carb oxami de

INF030 : (2R, 3 S)- 1 -(2-fluoro-6-methylbenzoyl)-N-(4-(hydroxymethyl)-3 -

(trifluoromethyl)phenyl)-2-(4-((tetrahydro-2H-pyran-4-yl)amino)phenyl)-l,2,3,4- tetrahydroquinoline-3-carboxamide INF033: (2R,3S)-2-(4-(cyclopentylamino)phenyl)-l-(2-fluoro-6-methylbenzoyl)-

N-(4-hydroxy-3-(trifluoromethyl)phenyl)-l,2,3,4-tetrahydroquinoline-3-carboxamide

INF034 : (2R, 3 S)- 1 -(2-fluoro-6-methylbenzoyl)-2-(4-(3 -hydroxy-3 - methylbutyl)phenyl)-N-(4-methyl-3-(trifluoromethyl)phenyl)-l,2,3,4-tetrahydroquinoline-3- carb oxami de

INF035: (2R,3S)-2-(4-(cyclopentylamino)phenyl)-l-(2-fluoro-6-methylbenzoyl)-

N-(3-(hydroxymethyl)phenyl)-l,2,3,4-tetrahydroquinoline-3-carboxamide

INF038: (2R,3S)-l-(2-fluoro-6-methylbenzoyl)-N-(4-(hydroxymethyl)-3-

(trifluoromethyl)phenyl)-2-phenyl-l,2,3,4-tetrahydroquinoline-3-carboxamide

INF039: (2R,3S)-2-(4-(cyclopentylamino)phenyl)-6-fluoro-l-(2-fluoro-6- methylbenzoyl)-N-(4-(hydroxymethyl)-3-(trifluoromethyl)phenyl)-l,2,3,4- tetrahydroquinoline-3-carboxamide

INF040: (2R,3S)-2-(4-(cyclopentylamino)phenyl)-N-(4-(hydroxymethyl)-3-

(trifluoromethyl)phenyl)-l-(2-methylbenzoyl)- 1,2, 3, 4-tetrahydroquinoline-3 -carboxamide

INF041: (2R,3S)-2-(4-(cyclopentylamino)phenyl)-l-(2-fluorobenzoyl)-N-(4-

(hydroxymethyl)-3-(trifluoromethyl)phenyl)- 1,2, 3, 4-tetrahydroquinoline-3 -carboxamide

INF045: (2R,3S)-2-(4-(cyclopentylamino)phenyl)-5-fluoro-l-(2-fluoro-6- methylbenzoyl)-N-(4-(hydroxymethyl)-3-(trifluoromethyl)phenyl)-l,2,3,4- tetrahydroquinoline-3-carboxamide

INF046: (2R,3S)-2-(4-(cyclopentylamino)phenyl)-7-fluoro-l-(2-fluoro-6- methylbenzoyl)-N-(4-(hydroxymethyl)-3-(trifluoromethyl)phenyl)-l,2,3,4- tetrahydroquinoline-3-carboxamide

INF047: (2R,3S)-6-chloro-2-(4-(cyclopentylamino)phenyl)-l-(2-fluoro-6- methylbenzoyl)-N-(4-(hydroxymethyl)-3-(trifluoromethyl)phenyl)-l,2,3,4- tetrahydroquinoline-3-carboxamide

INF048: (2R,3S)-l-(2-fluoro-6-methylbenzoyl)-2-(4-(3-hydroxy-3- methylbutyl)phenyl)-N-(4-(hydroxymethyl)-3-(trifluoromethyl)phenyl)-l,2,3,4- tetrahydroquinoline-3-carboxamide

INF049: (2R,3S)-l-(2-fluoro-6-methylbenzoyl)-N-(4-(hydroxymethyl)-3-

(trifluoromethyl)phenyl)-2-(4-(isopropylamino)phenyl)-l,2,3,4-tetrahydroquinoline-3- carb oxami de

INF050: (2R,3S)-2-(4-(cyclobutylamino)phenyl)-l-(2-fluoro-6-methylbenzoyl)-

N-(4-(hydroxymethyl)-3-(trifluoromethyl)phenyl)- 1,2, 3, 4-tetrahydroquinoline-3 -carboxamide INF051: (2R,3S)-l-(2-fluoro-6-methylbenzoyl)-2-(4-((2-hydroxy-2- methylpropyl)amino)phenyl)-N-(4-(hydroxymethyl)-3-(trifluoromethyl)phenyl)-l,2,3,4- tetrahydroquinoline-3-carboxamide

INF052: (2R,3S,5R)-2-(4-(cyclopentylamino)phenyl)-l-(2,6-difluorobenzoyl)-

N-(4-methyl-3-(trifluoromethyl)phenyl)-5-(trifluoromethyl)piperidine-3-carboxamide

INF053: (2R,3S,5R)-2-(4-(cyclopentylamino)phenyl)-l-(2,6-dimethylbenzoyl)-

INF055: (2R,3S)-2-(4-(cyclopentylamino)phenyl)-l-(2-fluoro-6-methylbenzoyl)-

N-(4-(hydroxymethyl)-3-(trifluoromethyl)phenyl)-6-(trifluoromethyl)-l,2,3,4- tetrahydroquinoline-3-carboxamide

INF056: (2R,3S,5R)-2-(4-(cyclopentylamino)phenyl)-l-(2-fluoro-6- methylbenzoyl)-N-(4-methyl-3-(trifluoromethyl)phenyl)-5-(trifluoromethyl)piperidine-3- carb oxami de

INF058 : (2R, 3 S)- 1 -(2-fluoro-6-methylbenzoyl)-2-(4-(2-hydroxy-2- methylpropoxy)phenyl)-N-(4-methyl-3-(trifluoromethyl)phenyl)- 1,2,3, 4-tetrahydroquinoline- 3 -carboxamide

INF067: (2R,3S,5R)-2-(4-((cyclopentyl-l-d)amino)phenyl)-l-(2,6- difluorobenzoyl)-N-(4-methyl-3-(trifluoromethyl)phenyl)-5-(trifluoromethyl)piperidine-3- carboxamide

INF068: (2R,3S,5R)-2-(4-(cyclopentylamino)phenyl)-l-(2,6-difluorobenzoyl)-

N-(4-hydroxy-3-(trifluoromethyl)phenyl)-5-(trifluoromethyl)piperidine-3-carboxamide

INF069: (2R,3S,5R)-2-(4-(cyclopentylamino)phenyl)-l-(2,6-difluorobenzoyl)-

N-(4-(hydroxymethyl)-3-(trifluoromethyl)phenyl)-5-(trifluoromethyl)piperidine-3- carboxamide

INF070: (2R,3S,5R)-l-(2,6-difluorobenzoyl)-N-(4-methyl-3-

(trifluoromethyl)phenyl)-2-(4-((tetrahydro-2H-pyran-4-yl)amino)phenyl)-5- (trifluoromethyl)piperidine-3-carboxamide

INF071 : (2R,3S,5R)-N-(3-chloro-4-methylphenyl)-2-(4-

(cyclopentylamino)phenyl)-l-(2,6-difluorobenzoyl)-5-(trifluoromethyl)piperidine-3- carb oxami de

INF072: (2R,3S,5R)-N-(3-chloro-4-hydroxyphenyl)-2-(4-

(cyclopentylamino)phenyl)-l-(2,6-difluorobenzoyl)-5-(trifluoromethyl)piperidine-3- carb oxami de INF075: (2R,3S,5R)-l-(2-chloro-6-fluorobenzoyl)-2-(4-

(cyclopentylamino)phenyl)-N-(4-methyl-3-(trifluoromethyl)phenyl)-5-

(trifluoromethyl)piperidine-3-carboxamide

INF077: (2R,3S,5R)-N-(4-chloro-3-(trifluoromethyl)phenyl)-2-(4-

INF080: (2R,3S,5R)-2-(4-(cyclopentylamino)phenyl)-N-(3,4-dichlorophenyl)-l-

(2,6-difluorobenzoyl)-5-(trifluoromethyl)piperidine-3-carboxamide

Methods for preparing these small molecule C5aR antagonists can be found in WO 2020/182384 Al.

In a preferred embodiment the inhibitor of C5a activity is INF052.

In a preferred embodiment the inhibitor of C5a activity is avacopan, having the structure of general formula (II):

In a preferred embodiment of all aspects of the present invention, the inhibitor of C5a activity is a protein ligand, wherein the protein ligand is an antibody or an antigen binding fragment thereof. More preferably the protein ligand comprises a VH and a VL domain of an antibody, a Fab fragment, a Fab’ fragment, a heavy chain antibody, a single-domain antibody (sdAb), variable domain of a heavy chain antibody, a VHH, a nanobody, a single-chain variable fragment (scFv), a tandem scFv, or a single-chain diabody.

In a preferred embodiment of all aspects of the present invention, the inhibitor of C5a activity is a protein ligand, wherein the protein ligand is an antibody-like protein, preferably an affibody, anticalin, or an designed ankyrin repeat protein. Antibody-like proteins include without limitation affibodies, anticalins, and designed ankyrin repeat proteins (for review see: Binz H.K. et al. (2005) Engineering novel binding proteins from non-immunoglobulin domains. Nat. Biotechnol. 23(10): 1257-1268). Antibody-like proteins can be derived from large libraries of mutants, e.g. be panned from large phage display libraries and can be isolated in analogy to regular antibodies. Also, antibody-like binding proteins can be obtained by combinatorial mutagenesis of surface-exposed residues in globular proteins. Antibody-like proteins are sometimes referred to as “peptide aptamers”.

In a preferred embodiment of all aspects of the present invention, the inhibitor of C5a activity is a protein ligand, wherein the protein ligand is an inhibitory variant of C5a.

In a preferred embodiment of all aspects of the present invention, the inhibitor of C5a activity is a protein ligand, wherein the protein ligand is an inhibitory variant of C5a receptor.

In preferred embodiments of all aspects of the invention, wherein the inhibitor of C5a activity is a protein ligand, preferably an antibody or antigen-binding fragment thereof, specifically binding to a conformational epitope of human C5a formed by (a) amino acid sequences NDETCEQRA (SEQ ID NO: 2) and SHKDMQL (SEQ ID NO: 3) of C5a binds to a conformational epitope of C5a formed by amino acid sequences NDETCEQRA (SEQ ID NO: 2) and SHKDMQL (SEQ ID NO: 3), and binds to at least one amino acid within the amino acid sequence according to SEQ ID NO: 2 and to at least one amino acid within the amino acid sequence according to SEQ ID NO: 3. In other words, the inhibitor of C5a activity according to this preferred embodiment binds at the same time to at least one amino acid within the amino acid sequence according to SEQ ID NO: 2 and to at least one amino acid within the amino acid sequence according to SEQ ID NO: 3. SEQ ID NO: 2 corresponds to amino acids 30-38 of human C5a. SEQ ID NO: 3 corresponds to amino acids 66-72 of human C5a. The amino acid sequence of human C5a is depicted in SEQ ID NO: 1. In more preferred embodiments, the inhibitor of C5a activity binds to at least one of amino acids DETCEQR (SEQ ID NO: 4). SEQ ID NO: 4 corresponds to amino acids 31-37 of human C5a. In more preferred embodiments, the inhibitor of C5a activity binds to at least one of amino acids HKDMQ (SEQ ID NO: 5), more preferably to at least one of amino acids KDM. SEQ ID NO: 5 correspond to amino acids 67-71 of human C5a; the sequence KDM corresponds to amino acids 68-70 of human C5a. In particularly preferred embodiments, the inhibitor of C5a activity binds at the same time to at least one amino acid within the amino acid sequence DETCEQR (SEQ ID NO: 4) and to at least one amino acid within the amino acid sequence KDM.

In a preferred embodiment the specific binding to the amino acids of the conformational epitope is determined by alanine scanning. In a preferred embodiment the conformational epitope is determined by alanine scanning.

The skilled person is aware of assays for screening antibodies binding to the specified conformational epitope. One such suitable assay is described in the following:

In 3-D structure of C5a obtained from computer modeling method, the spatial epitopes containing peptide C5a 28-40 (VNNDETCEQRAAR, SEQ ID NO: 53) and C5a peptide 65-70 (ISHKDM, SEQ ID NO: 54) can be viewed as random coils. When the two peptides are linked by a flexible peptide linker, GGGGS (SEQ ID NO: 55), the spatial epitopes is reconstructed resembling the parent antigen conformation, as the weak hydrophobic interaction from the two peptides ensures a pocket-shape conformation. Computer modeling analysis of the peptide NH2-28-40-Linker(GGGGS)-65-70-COOH maintains the same conformation as the parent antigen. This new 24-AA peptide can be synthesized and conjugated with keyhole limpet hemocyanin (KLH) to form an immunogen to immunize mice, and the traditional hybridoma technology can be subsequently applied to obtain INab308 and INab708 using the new 24-AA peptide based ELISA as a screening tool. A 96-well ELISA plate is coated with 1-2 wg/mL synthetic peptides with the conformational epitope at 4°C overnight. After being blocked with 5% nonfat milk in PBS at 37°C for 1 h, 50 «L of culture media of the hybridoma growing clones are added to each well and incubated at 37°C for 1 h, followed by 100 «L of goat antimouse antibody labeled with horseradish peroxidase (HRP) for 1 h. The peroxidase reaction is developed with color development solution containing 5.5 mM o-phenylene-diamine hydrochloride (OPD) and 8.5 mM H2O2. The light absorbance is measured at 492 nm with an ELISA reader.

In a preferred embodiment of all aspects of the present invention wherein the inhibitor of C5a activity is an antibody or antigen-binding fragment thereof specifically binding to C5a comprising a variable domain of a heavy chain (VH) and a variable domain of a light chain (VL).

Preferably the VL comprises a light chain CDR3 sequence CQQSNEDPYT as set forth in SEQ ID NO: 6. In a preferred embodiment the VL further comprises a FR2 sequence WYQQKPGQPPKLL as set forth in SEQ ID NO: 8 or SEQ ID NO: 39.

Preferably the VL comprises a light chain CDR3 sequence CQQNNEDPLT as set forth in SEQ ID NO: 7. In a preferred embodiment the VL further comprises a FR2 sequence WYQQKPGQPPKLL as set forth in SEQ ID NO: 8 or SEQ ID NO: 39.

In a preferred embodiment the inhibitor of C5a activity further comprises at least one of the following sequences:

(i) a heavy chain CDR2 sequence IDPSDSESRLDQ according to SEQ ID NO: 9;

(ii) a heavy chain CDR2 sequence ILPGSGSTNYNE according to SEQ ID NO: 10;

(iii) a light chain CDR2 sequence IYAASNL according to SEQ ID NO: 11;

(iv) a light chain CDR2 sequence IYAASNL according to SEQ ID NO: 12;

(v) a heavy chain CDR1 sequence CKASGYSFTTFWMD according to SEQ ID NO: 13; (vi) a heavy chain CDR1 sequence CKATGNTFSGYWIE according to SEQ ID NO: 14;

(vii) a light chain CDR1 sequence CKASQSVDYDGDSYMK according to SEQ ID NO: 15;

(viii) a light chain CDR1 sequence CKASQSVDYDGDSYMN according to SEQ ID NO: 16;

(ix) a heavy chain CDR3 sequence CARGNDGYYGFAY according to SEQ ID NO: 17; or

(x) a heavy chain CDR3 sequence CTRRGLYDGSSYFAY according to SEQ ID NO: 18.

In a preferred embodiment the inhibitor of C5a activity comprises a light chain CDR3 sequence according to SEQ ID NO: 6, a light chain CDR2 sequence according to SEQ ID NO:

11, a light chain CDR1 sequence according to SEQ ID NO: 15, a heavy chain CDR3 sequence according to SEQ ID NO: 17, a heavy chain CDR2 sequence according to SEQ ID NO: 9, and a heavy chain CDR1 sequence according to SEQ ID NO: 13. In a preferred embodiment the inhibitor of C5a activity further comprises the light chain framework regions (FR) 1 to 4 according to SEQ ID NOs: 19, 8, 20 and 21, respectively; preferably further comprising the heavy chain FR 1 to 4 according to SEQ ID NOs: 23, 24, 25 and 26, respectively. In an alternative preferred embodiment the inhibitor of C5a activity further comprises the light chain framework regions (FR) 1 to 4 according to SEQ ID NOs: 37, 39, 41 and 43, respectively; preferably further comprising the heavy chain FR 1 to 4 according to SEQ ID NOs:45, 47, 49 and 51, respectively.

In a preferred embodiment the inhibitor of C5a activity comprises a light chain CDR3 sequence according to SEQ ID NO: 7, a light chain CDR2 sequence according to SEQ ID NO:

12, and a light chain CDR1 sequence according to SEQ ID NO: 16, a heavy chain CDR3 sequence according to SEQ ID NO: 18, a heavy chain CDR2 sequence according to SEQ ID NO: 10, and a heavy chain CDR1 sequence according to SEQ ID NO: 14. In a preferred embodiment the inhibitor of C5a activity further comprises the light chain framework regions (FR) 1 to 4 according to SEQ ID NOs:28, 8, 29 and 30, respectively; preferably further comprising the heavy chain FR 1 to 4 according to SEQ ID NOs:32, 33, 34 and 35, respectively.

In a preferred embodiment the FR sequences have a sequence identity to the herein disclosed FR sequences of at least 99%, at least 98% at least 95%, at least 90%, at least 85%, at least 80% or at least 75% sequence. In a preferred embodiment according to all ascpects of the invention the inhibitor of C5a activity is selected from IFX-1 (vilobelimab), IFX-2, INab708, BNJ364, BNJ367, BNJ371, BNJ378, BNJ366, BNJ369, BNJ381, BNJ383, MEDI-7814 or ALXN-1007, or an antigenbinding fragment thereof. In a preferred embodiment according to all ascpects of the invention the inhibitor of C5a activity is IFX-1 (vilobelimab).

The sequences of IFX-1, INab708 and IFX-2 can be found in Table 1 below.

Table 1: FR1, CDR1, FR2, CDR2, FR3, CDR3, and FR4 sequences of VL and VH domains of suitable inhibitors of C5a activity

In a preferred embodiment according to all ascpects of the invention the inhibitor of C5a activity is selected from an antibody or antigen binding fragment thereof that competes for binding with any of the antibodies selected from:IFX-l (vilobelimab), IFX-2, INab708, BNJ364, BNJ367, BNJ371, BNJ378, BNJ366, BNJ369, BNJ381, BNJ383, MEDI-7814 or ALXN-1007.

In a preferred embodiment according to all aspects of the invention the inhibitor of C5a activity is an antibody or antigen-binding fragment thereof that specifically binds to human C5a comprises (i) a light chain variable domain (VL) having at least 99%, at least 98% at least 95%, at least 90%, at least 85%, at least 80%, at least 75% sequence identity with the VL domain according to SEQ ID NO: 22 and (ii) a heavy chain variable domain (VH) having at least 99%, at least 98% at least 95%, at least 90%, at least 85%, at least 80%, at least 75% sequence identity with the VH domain according to SEQ ID NO: 27. In a preferred embodiment the sequence variation does not include the CDR sequences.

In a preferred embodiment according to all aspects of the invention the inhibitor of C5a activity is an antibody or antigen-binding fragment thereof that specifically binds to human C5a comprises (i) a light chain variable domain (VL) according to SEQ ID NO: 22 and (ii) a heavy chain variable domain (VH) according to SEQ ID NO: 27. In a preferred embodiment according to all aspects of the invention the inhibitor of C5a activity is an antibody or antigen-binding fragment thereof that specifically binds to human C5a comprises (i) a light chain variable domain (VL) having at least 99%, at least 98% at least 95%, at least 90%, at least 85%, at least 80%, at least 75% sequence identity with the VL domain according to SEQ ID NO: 31 and (ii) a heavy chain variable domain (VH) having at least 99%, at least 98% at least 95%, at least 90%, at least 85%, at least 80%, at least 75% sequence identity with the VH domain according to SEQ ID NO: 36. In a preferred embodiment the sequence variation does not include the CDR sequences.

In a preferred embodiment according to all aspects of the invention the inhibitor of C5a activity is an antibody or antigen-binding fragment thereof that specifically binds to human C5a comprises (i) a light chain variable domain (VL) according to SEQ ID NO: 31 and (ii) a heavy chain variable domain (VH) according to SEQ ID NO: 36.

In a preferred embodiment according to all aspects of the invention the inhibitor of C5a activity is an antibody or antigen-binding fragment thereof that specifically binds to human C5a comprises (i) a light chain variable domain (VL) having at least 99%, at least 98% at least 95%, at least 90%, at least 85%, at least 80%, at least 75% sequence identity with the VL domain according to SEQ ID NO: 44 and (ii) a heavy chain variable domain (VH) having at least 99%, at least 98% at least 95%, at least 90%, at least 85%, at least 80%, at least 75% sequence identity with the VH domain according to SEQ ID NO: 52. In a preferred embodiment the sequence variation does not include the CDR sequences.

In a preferred embodiment according to all aspects of the invention the inhibitor of C5a activity is an antibody or antigen-binding fragment thereof that specifically binds to human C5a comprises (i) a light chain variable domain (VL) according to SEQ ID NO: 44 and (ii) a heavy chain variable domain (VH) according to SEQ ID NO: 52.

In a preferred embodiment according to all aspects of the present invention the inhibitors of C5a activity are antibodies or antigen binding fragments thereof disclosed herein comprising one, two or three modified amino acids within the CDR sequences. The modified amino acids are selected from substitution, insertion or deletion, preferably substitution. In a preferred embodiment the one, two or three modified amino acids are conservative amino acid substitutions. “Conservative substitutions” may be made, for instance, on the basis of similarity in polarity, charge, size, solubility, hydrophobicity, hydrophilicity, and/or the amphipathic nature of the amino acid residues involved. Amino acids can be grouped into the following six standard amino acid groups:

(1) hydrophobic: Met, Ala, Vai, Leu, He; (2) neutral hydrophilic: Cys, Ser, Thr, Asn, Gin;

(3) acidic: Asp, Glu;

(4) basic: His, Lys, Arg;

(5) residues that influence chain orientation: Gly, Pro; and

(6) aromatic: Trp, Tyr, Phe.

As used herein, “conservative amino acid substitutions” are defined as exchanges of an amino acid by another amino acid listed within the same group of the six standard amino acid groups shown above. For example, the exchange of Asp by Glu retains one negative charge in the so modified polypeptide. In addition, glycine and proline may be substituted for one another based on their ability to disrupt a-helices. Some preferred conservative substitutions within the above six groups are exchanges within the following sub-groups: (i) Ala, Vai, Leu and He; (ii) Ser and Thr; (ii) Asn and Gin; (iv) Lys and Arg; and (v) Tyr and Phe. Given the known genetic code, and recombinant and synthetic DNA techniques, the skilled scientist readily can construct DNAs encoding the conservative amino acid variants.

The inhibitors of C5a activity disclosed herein may freely be combined with the inhibitors of IL-6 activity for the claimed use.

In a preferred embodiment the inhibitor of C5a activity is vilobelimab and the inhibitor of IL-6 activity is tocilizumab.

Infectious pneumonia and infectious acute respiratory distress syndrome (ARDS)

Pneumonia is a medical condition of the lung characterized by inflammation of the lung tissue in particular the aleveoli. Pneumonia can be caused by various pathogens, including bacteria, viruses, fungi, and other microorganisms. The infection causes the alveoli in the lungs to become filled with fluid, pus, and cellular debris, which impairs the lungs' ability to efficiently exchange oxygen and carbon dioxide.

In a preferred embodiment the infectious pneumonia is viral pneumonia, bacterial pneumonia or fungal pneumonia, preferably viral pneumonia or bacterial pneumonia, more preferably viral pneumonia. Viral pneumonia may be caused by various viruses including but not limited to influenza virus A or B, respiratory syncytial virus, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Preferably the infectious viral pneumonia is caused by SARS-CoV-2.

In a more preferred embodiment the infectious pneumonia is COVID-19 pneumonia, i.e. viral pneumonia caused by SARS-CoV-2 infection. Acute respiratory distress syndrome (ARDS) is a severe and life-threatening condition that affects the lungs. ARDS is characterized by inflammation and damage to the alveoli. This damage results in increased permeability of the alveolar-capillary membrane, causing fluid leakage into the alveoli impairing their ability to effectively exchange oxygen and carbon dioxide.

In a preferred embodiment the ARDS is viral ARDS or bacterial ARDS. In a more preferred embodiment the viral ARDS is COVID-19 ARDS.

Administration regimen

In a preferred embodiment the inhibitor of C5a activity or the inhibitor of IL-6 activity are for administration in a regime comprising an induction phase followed by a maintenance phase. Preferably, the inhibitor of C5a activity is administered in the induction phase and the maintenance phase and the inhibitor of IL-6 activity is administered:

(I) within 0-30 days, preferably within 0-15 days, more preferably within 0-7 days, most preferably within 0-1 days, prior to the induction phase,

(II) during the induction phase, and/or

(III) during the maintenance phase.

In a preferred embodiment, an additional second dose of the inhibitor of IL-6 activity is administered according to (I), (II) or (III).

In a preferred embodiment, the inhibitor of C5a activity is administered in the induction phase and the maintenance phase and the inhibitor of IL-6 activity is administered within 1 to 4 weeks, preferably within 1-2 weeks, more preferably within 1 week, prior to the induction phase.

In a preferred embodiment, the inhibitor of C5a activity is administered in the induction phase and the maintenance phase and the inhibitor of IL-6 activity is administered 1 to 14 days, preferable 1 to 7 days, prior to the induction phase.

In a preferred embodiment, the inhibitor of C5a activity is administered in the induction phase and the maintenance phase and the inhibitor of IL-6 activity is administered during the induction phase.

In a preferred embodiment, the inhibitor of C5a activity is administered in the induction phase and the maintenance phase and the inhibitor of IL-6 activity is administered during the maintenance phase.

In a preferred embodiment, the inhibitor of C5a activity is administered before the inhibitor of IL-6 activity In a preferred embodiment the induction phase has a duration of 1 to 10 days, preferably 2 to 8 days, more preferably 8 days.

In a preferred embodiment during the induction phase 1 to 8 doses, preferably 2 to 6 doses, more preferably 3 to 5 doses, most preferably 4 doses, of the inhibitor of C5a activity (preferably vilobelimab, INab708 or IFX-2, more preferably vilobelimab) are administered.

In a preferred embodiment, each dose administered in the induction phase comprises 200-1600mg, preferably 400-1200mg, more preferably 600-1000mg, most preferably 800mg, of the inhibitor of C5a activity (preferably vilobelimab, INab708 or IFX-2, more preferably vilobelimab).

In a preferred embodiment the inhibitor of C5a activity (preferably vilobelimab, INab708 or IFX-2, more preferably vilobelimab) is administered by intravenous infusion or injection, preferably infusion.

In a preferred embodiment the maintenance phase has a duration of 1 to 4 weeks, preferably 2-3 weeks, most preferably 2 weeks.

In a preferred embodiment during the maintenance phase, the inhibitor of C5a activity (preferably vilobelimab, INab708 or IFX-2, more preferably vilobelimab) is administered every 1 to 4 weeks, preferably 1 to 2 weeks, more preferably every week.

In a preferred embodiment, each dose administered in the maintenance phase comprises 200-1600mg, preferably 400-1200mg, more preferably 600-1000mg, most preferably 800mg, of the inhibitor of C5a activity (preferably vilobelimab, INab708 or IFX-2, more preferably vilobelimab).

In a preferred embodiment, the inhibitor of C5a activity and the inhibitor of IL-6 activity are used in an administration regimen, wherein

(i) the induction phase comprises or essentially consists of a period of 1 to 10 days, preferably 2 to 8 days, more preferably 7-8 days, wherein 1-8 doses, preferably 2-4 doses, comprising each 200-1600 mg, preferably 400-1200 mg of said inhibitor of C5a activity (preferably vilobelimab, INab708 or IFX-2, more preferably vilobelimab), are administered; and

(ii) the maintenance phase comprises or essentially consists of a period of at least 1 week, preferably 2-4 weeks, wherein a dose, comprising 200-1600 mg, preferably 400-1200 mg of said inhibitor of C5a activity (preferably vilobelimab, INab708 or IFX-2, more preferably vilobelimab), is administered every 1-4 weeks, preferably every week.

In a preferred embodiment, the inhibitor of C5a activity (preferably vilobelimab, INab708 or IFX-2, more preferably vilobelimab) is administered within the induction and the maintenance phase at a total maximum of 4 to 12 doses, preferably 6 to 10 doses, more preferably 6 to 8 doses, most preferably 6 doses.

(i) the induction phase essentially consists of a period of 8 days, wherein 4 doses comprising each 800 mg of the inhibitor of C5a activity (preferably vilobelimab, INab708 or IFX-2, more preferably vilobelimab), are administered (preferably on days 1, 2, 4 and 8); and

(ii) the maintenance phase essentially consists of a period of 2 weeks, wherein a dose, comprising 800 mg of the inhibitor of C5a activity (preferably vilobelimab, INab708 or IFX-2, more preferably vilobelimab), is administered every 1 week (preferably on day 15 and 22 of the treatment).

In a preferred embodiment, the inhibitor of IL-6 activity (preferably tocilizumab) is administered at a dose of 200-1600mg per dose, preferably 400-1200mg, more preferably 600- lOOOmg, most preferably 800mg.

In a preferred embodiment, the inhibitor of IL-6 activity (preferably tocilizumab) is administered at a dose of 2 mg/kg to 12 mg/kg, preferably 3 mg/kg to 10 mg/kg, more preferably 4 mg/kg to 8 mg/kg.

In a preferred embodiment, the inhibitor of IL-6 activity (preferably tocilizumab) is administered at a weight dependent dose of 8mg/kg for patients at or above 30 kg weight or 12 mg/kg for patients of less than 30 kg weight.

In a preferred embodiment, the inhibitor of IL-6 activity (preferably tocilizumab) is administered at a maximum dose of 800 mg per administration.

In a preferred embodiment, the inhibitor of IL-6 activity (preferably tocilizumab) is administered in 1 to 4 doses, preferably 1-2 doses.

In a preferred embodiment, the inhibitor of IL-6 activity (preferably tocilizumab) is administered as a single dose.

In a preferred embodiment, the inhibitor of IL-6 activity (preferably tocilizumab) is administered as a first and second dose. A second dose is in particular beneficial if clinical signs or symptoms do not improve after the first dose. Preferably, the additional dose is at administered at least 8 hours after the first dose.

In a preferred embodiment, each further dose of the inhibitor of IL-6 activity (preferably tocilizumab) is administered at least 8 hours after the previous administration.

In a preferred embodiment, an additional dose of the inhibitor of IL-6 activity (preferably tocilizumab) is administered 8-24 hours after the first dose. In a preferred embodiment, the inhibitor of IL-6 activity (preferably tocilizumab) is administered every 1 to 4 weeks, preferably every 1 to 2 weeks, preferably weekly.

In a preferred embodiment, the inhibitor of IL-6 activity (preferably tocilizumab) is administered by intravenous infusion or injection, preferably infusion.

In a preferred embodiment, each dose of the inhibitor of IL-6 activity (preferably tocilizumab) is administered prior to the induction phase.

In a preferred embodiment, the inhibitor of IL-6 activity (preferably tocilizumab) is administered as 1-2 doses, preferably single dose, prior (preferably 1-2 weeks prior, more preferably within 1 week prior) to the induction phase.

In a preferred embodiment, the inhibitor of IL-6 activity (preferably tocilizumab) is administered within the induction phase.

In a preferred embodiment, the inhibitor of IL-6 activity (preferably tocilizumab) is administered in more than a single dose, wherein at least one dose is administered prior to the induction phase and at least one dose is administered in the induction phase and/or maintenance phase.

In a preferred embodiment, the inhibitor of IL-6 activity (preferably tocilizumab) is administered in more than a single dose, wherein at least one dose is administered prior to the induction phase and at least one dose is administered in the induction phase.

In a preferred embodiment, the inhibitor of IL-6 activity (preferably tocilizumab) is administered in more than a single dose, wherein at least one dose is administered in the induction phase and at least one dose is administered in the maintenance phase.

(i) 1 or 2 doses (preferably single dose) of the inhibitor of IL-6 activity (preferably tocilizumab) is administered within 0 to 14 days prior and/or after the start of the induction phase (preferably within 0 to 7 days (i.e. prior or after) of the start of the induction phase, more preferably within 24 hours (i.e. prior or after) of the start of the induction phase), preferably the inhibitor of IL-6 activity (preferably tocilizumab) is administered at a weight dependent dose of 8mg/kg for patients at or above 30 kg weight or 12 mg/kg for patients of less than 30 kg weight;

(ii) the induction phase comprises or essentially consists of a period of 1 to 10 days, preferably 2 to 8 days more preferably 7-8 days, wherein 1-8 doses, preferably 2-4 doses, comprising each 200-1600 mg, preferably 400-1200 mg of the inhibitor of C5a activity (preferably vilobelimab, INab708 or IFX-2, more preferably vilobelimab), are administered; and

(iii) the maintenance phase comprises or essentially consists of a period of at least 2 weeks, preferably 2-4 weeks, wherein a dose, comprising 200-1600 mg, preferably 400-1200 mg of said inhibitor of C5a activity (preferably vilobelimab, INab708 or IFX-2, more preferably vilobelimab), is administered every 1-4 weeks, preferably every week.

(i) the induction phase comprises or essentially consists of a period of 1 to 10 days, preferably 2 to 5 days, wherein 1-8 doses, preferably 2-4 doses, comprising each 200-1600 mg, preferably 400-1200 mg of the inhibitor of C5a activity (preferably vilobelimab, INab708 or IFX-2, more preferably vilobelimab), are administered;

(ii) 1 or 2 doses (preferably single dose) of the inhibitor of IL-6 activity (preferably tocilizumab) is administered within the induction phase; and

(i) 1 or 2 doses (preferably single dose) of the inhibitor of IL-6 activity (preferably tocilizumab) is administered 1-2 weeks (preferably within 1 week of start of induction phase) prior to the induction phase;

(ii) the induction phase comprises or essentially consists of a period of 1 to 10 days, preferably 2 to 5 days, wherein 1-8 doses, preferably 2-4 doses, comprising each 200-1600 mg, preferably 400-1200 mg of the inhibitor of C5a activity (preferably vilobelimab, INab708 or IFX-2, more preferably vilobelimab), are administered;

(iii) 1 or 2 doses (preferably single dose) of the inhibitor of IL-6 activity (preferably tocilizumab) is administered within the induction phase; and

(iv) the maintenance phase comprises or essentially consists of a period of at least 2 weeks, preferably 2-4 weeks, wherein a dose, comprising 200-1600 mg, preferably 400-1200 mg of said inhibitor of C5a activity (preferably vilobelimab, INab708 or IFX-2, more preferably vilobelimab), is administered every 1-4 weeks, preferably every week. In a preferred embodiment, the inhibitor of C5a activity and the inhibitor of IL-6 activity are used in an administration regimen, wherein

(ii) 1 or 2 doses (preferably single dose) of the inhibitor of IL-6 activity (preferably tocilizumab) is administered within the induction phase;

(iii) the maintenance phase comprises or essentially consists of a period of at least 2 weeks, preferably 2-4 weeks, wherein a dose, comprising 200-1600 mg, preferably 400-1200 mg of said inhibitor of C5a activity (preferably vilobelimab, INab708 or IFX-2, more preferably vilobelimab), is administered every 1-4 weeks, preferably every week; and

(iv) 1 or 2 doses (preferably single dose) of the inhibitor of IL-6 activity (preferably tocilizumab) is administered within the maintenance phase.

(i) 1 or 2 doses (preferably single dose) of the inhibitor of IL-6 activity (preferably tocilizumab) is administered within 0 to 14 days prior and/or after the start of the induction phase (preferably within 0 to 7 days (i.e. prior or after) of the start of the induction phase);

(iii) 1 or 2 doses (preferably single dose) of the inhibitor of IL-6 activity (preferably tocilizumab) is administered within the induction phase;

(iv) the maintenance phase comprises or essentially consists of a period of at least 2 weeks, preferably 2-4 weeks, wherein a dose, comprising 200-1600 mg, preferably 400-1200 mg of said inhibitor of C5a activity (preferably vilobelimab, INab708 or IFX-2, more preferably vilobelimab), is administered every 1-4 weeks, preferably every week; and

(v) 1 or 2 doses (preferably single dose) of the inhibitor of IL-6 activity (preferably tocilizumab) is administered within the maintenance phase.

In a preferred embodiment, the inhibitor of C5a activity and the inhibitor of IL-6 activity are used in an administration regimen, wherein (i) the induction phase comprises or essentially consists of a period of 1 to 10 days, preferably 2 to 5 days, wherein 1-8 doses, preferably 2-4 doses, comprising each 200-1600 mg, preferably 400-1200 mg of the inhibitor of C5a activity (preferably vilobelimab, INab708 or IFX-2, more preferably vilobelimab), are administered;

(ii) the maintenance phase comprises or essentially consists of a period of at least 2 weeks, preferably 2-4 weeks, wherein a dose, comprising 200-1600 mg, preferably 400-1200 mg of said inhibitor of C5a activity (preferably vilobelimab, INab708 or IFX-2, more preferably vilobelimab), is administered every 1-4 weeks, preferably every week; and

(iii) 1 or 2 doses (preferably single dose) of the inhibitor of IL-6 activity (preferably tocilizumab) is administered within the maintenance phase.

(i) 1 dose of the inhibitor of IL-6 activity (preferably tocilizumab) is administered within 24 hours (i.e. prior or after) of the first administration of the inhibitor of C5a activity (preferably vilobelimab); optionally a second dose of the inhibitor of IL-6 activity (preferably tocilizumab) is administered, preferably after at least 8 hours of the first dose of the inhibitor of IL-6 activity; wherein the inhibitor of IL-6 activity (preferably tocilizumab) is administered at a weight dependent dose of 8mg/kg for patients at or above 30 kg weight or 12 mg/kg for patients of less than 30 kg weight; (ii) the inhibitor of C5a activity (preferably vilobelimab) is administered on day 1, day 2, day 4, day 8, day 15 and day 22, wherein the inhibitor of C5a activity (preferably vilobelimab) is administered at a dose of 800 mg.

Group of patients

In a preferred embodiment the inhibitor of C5a activity or the inhibitor of IL-6 activity are for use in treating patients that are on invasive mechanical ventilation, preferably not more than 48h post intubation upon first administration of the inhibitor of C5a activity.

In a preferred embodiment the inhibitor of C5a activity or the inhibitor of IL-6 activity are for use in treating patients that have a Path / FiCL ratio of between 50 and 300, preferably between 60 and 200.

The ratio of partial pressure of oxygen in arterial blood (Path) to the fraction of inspiratory oxygen concentration (FiCL) is a clinical indicator of hypoxaemia. PaCL/FiCL ratio is used inter alia to classify severity of acute respiratory distress syndrome (ARDS). In a preferred embodiment the following classification of ARDS severity is used: mild (PaCL/FiCL ratio 200-300), moderate (PaCL/FiCL ratio 100-200) and severe (PaCL/FiCL ratio <100).

In a preferred embodiment the inhibitor of C5a activity or the inhibitor of IL-6 activity are for use in treating patients with mild to severe (preferably moderate to severe) ARDS.

Kit of parts

In a third aspect, the present invention provides a kit of parts comprising an inhibitor of C5a activity (preferably vilobelimab) and an inhibitor of IL-6 activity (preferably tocilizumab). Preferably, the kit is further comprising instructions for the use of the inhibitor of C5a activity (preferably vilobelimab) and the inhibitor of IL-6 activity (preferably tocilizumab) and/or means for the application of the compounds.

In a preferred embodiment the kit of parts comprises the inhibitor of C5a activity (preferably vilobelimab) in a dosage form comprising 100-2000 mg, 200-1500mg, 400- 1200mg, preferably 600-1000 mg, more preferably 800mg of an inhibitor of C5a activity (preferably vilobelimab). Preferably wherein the dosage form is a lyophilized powder, or a liquid dosage form, preferably a solution for infusion or a solution for injection.

In a preferred embodiment the kit of parts comprises the inhibitor of IL-6 activity (preferably tocilizumab) in a dosage form comprising 100-2000 mg, 200-15 OOmg, 400- 1200mg, preferably 600-1000 mg, more preferably 800mg of an inhibitor of IL-6 activity (preferably tocilizumab). Preferably wherein the dosage form is a lyophilized powder, or a liquid dosage form, preferably a solution for infusion or a solution for injection.

Method of treatment

In a further aspect of the invention a method for the treatment of patients with an infectious pneumonia and/or infectious acute respiratory distress syndrome (ARDS), wherein the method is comprising administering to the patient an effective amount of an inhibitor of C5a activity and an inhibitor of IL-6 activity. In a preferred embodiment the method comprises administering the inhibitor of IL-6 activity prior and/or concomitant with the inhibitor of C5a- activity.

In a third aspect, the present invention provides the use of an inhibitor of C5a activity and an inhibitor of IL-6 activity for the manufacturing of a medicament for the treatment of infectious pneumonia and/or infectious acute respiratory distress syndrome (ARDS).

Examples

The following Examples are provided for further illustration of the invention. The invention, however, is not limited thereto, and the following Examples merely show the practicability of the invention on the basis of the above description.

Example 1: Phase II/III study evaluating IFX-1 for the treatment of COVID 19 related severe pneumonia

A) Rationale for the study

Neutrophil driven tissue and organ damage is known to play an important role in a wide array of acute inflammatory diseases. The mechanism leading to damage has been largely attributed to two mechanisms: 1) the release of granular enzymes and 2) the generation of so- called reactive oxygen species in which O2 radical formation elicits a damaging effect.

One of the strongest chemoattractant substances, which is also capable of inducing both mechanisms described above is the human complement split product C5a.

Earlier research by applicant has demonstrated that the anti-human C5a antibody IFX- 1 could significantly reduce the neutrophil and macrophage infiltration in a model of viral (H7N9)-induced lung injury in monkeys (Sun et al. 2015). This was accompanied by a significantly reduced tissue damage in the lung of infected animals and also a significantly reduced viral replication when compared to mock-treated animals. The mechanism was then confirmed in a model of MERS-CoV-induced lung injury where similar findings were made by using an anti-C5a receptor antibody (Jiang et al. 2018) and in a model of SARS-CoV- induced lung injury by using complement C3 knockout mice (Gralinski et al. 2018). The latter study also provided evidence for a profound complement activation in SARS virus infections in animals. These studies all suggested a role of neutrophil driven lung damage, which was induced by generation of C5a in different viral-lung injury models, including SARS viruses.

Latest data from a collaborating research group in China demonstrated strongly and significantly elevated C5a levels in severely diseased COVID-19 patients when compared to mildly diseased patients (Gao et al. 2020; Carvelli et al. 2020) and revealed evidence for a strong complement pathway driven activation of C5a in this disease. In addition, data from the first two severely diseased COVID 19 patients treated with the IFX-1 cell line derived anti-C5a antibody BDB-1, which InflaRx licensed to a collaborator in China, demonstrated clinical improvement in oxygenation index, fever reduction, and laboratory parameter normalization including liver enzymes and lymphocyte counts.

From a clinical perspective, various papers have confirmed that COVID-19 infected non-surviving patients demonstrated lung failure with close to 100% (Zhou et al. 2020) and that, in contrast to surviving patients, non-survivors demonstrated elevated white blood cell counts and neutrophils above the normal range (Wang et al. 2020; Gong et al. 2020).

In summary, there is evidence that in COVID-19 patients who are severely affected, C5a activation occurs to a large extent and that neutrophil count elevation in blood is associated with bad outcome. These human data fit well to the scientific rationale developed in animal models of viral-induced lung injury that activated neutrophils attracted to the lung may cause viral-induced lung damage. First treatment attempts with the anti-C5a antibody technology developed by InflaRx (BDB-1) in severely affected COVID-19 patients provide further evidence for the scientific rationale.

The completed Phase II portion of the current trial was exploratory in nature and was not powered to show statistically significant differences in clinical endpoints. Relative change (%) from baseline to day 5 in the oxygenation index, chosen as the primary endpoint for Phase II, showed a large variability and dependency on patient positioning and intubation status which excluded this endpoint from being used in a confirmatory study. Phase III of the study is an adequately powered, placebo-controlled, double blinded phase evaluating standard of care (SOC) + IFX-1 versus SOC + placebo-to-match with 28-day all-cause mortality as the primary endpoint, an accepted regulatory primary endpoint for critical care studies. At the time that Phase II of this study was initiated, there was no SOC established for this newly identified disease. The SOC to be utilized in Phase III of this study reflects the current understanding of the SOC for hospitalized patients with COVID-19, which includes venous thromboembolism (VTE) prophylaxis at a minimum, and may include other international and country-specific recommended treatments for COVID-19 per the locally adopted treatment recommendations.

Rationale for dosage regimen

The aim for determining the dose and administration frequency for IFX-1 is to establish a pragmatic administration schedule for the COVID-19 patient population. IFX-1 dose and administration schedule was chosen based on prior pharmacokinetic (PK)/pharmacodynamic (PD) observations for IFX-1 trough values and blood C5a levels, dose-response assessment in Study IFX-1 in Hidradentis suppurativa, and the described unprecedented high C5a levels in patients with severe COVID-19 related pneumonia (Gao et al. 2020; Carvelli et al. 2020). In a population PK/PD modelling study for IFX 1 based on the data of the previous trials with IFX- 1, a reduction in C5a concentration was found to be dependent on all measures of drug exposure, with increasing exposure predicting a greater reduction in C5a.

Based on the above data, the dosing schedule of IFX-1 for this study includes an additional dose of 800 mg IFX 1 at day 2 in the established fractionated loading dose scheme, that foresees administration of 800 mg at days 1, 4, and 8. This additional dose has been chosen due to the reported high C5a levels in COVID-19 patients (Gao et al. 2020). Therefore, the entire dosing scheme contains up to 6 IFX-1 doses of 800 mg at days 1, 2, 4, 8, 15, and 22 (or less until hospital discharge). This regimen had been employed in Phase II of this study, leading to a lower death rate and supporting efficacy signals without any new signals of unknown toxicities (Vlaar et al 2020).

B) Objectives of the study

Primary Objectives

The primary objective of Phase III is:

• To demonstrate the efficacy of IFX-1 to improve survival outcomes of severe CO VID 19 pneumonia (confirmative)

Secondary Objectives

The secondary objectives of Phase III are: To assess and define other parameters of efficacy

To assess the safety of IFX-1

C) Study design

Overall design

This is a pragmatic, adaptive, randomized, multicenter phase II/III study evaluating IFX-1 for the treatment of CO VID 19 related severe pneumonia. Phase III is a double-blind, placebo-controlled, randomized phase evaluating SOC + IFX-1 (Arm A) and SOC + placebo- to-match (Arm B). The SOC includes VTE prophylaxis at a minimum, and may include other international and country-specific recommended treatments for COVID-19 per the locally adopted treatment recommendations.

Phase III of the study will randomize up to 400 patients with one interim analysis for stopping for futility. A total of 180 patients are planned to be randomized into Arm A and Arm B using a 1 : 1 allocation ratio for the first stage; based on results of the interim analysis, up to an additional 180 patients are planned to be randomized using the same allocation ratio for the second stage. Additional patients will be randomized under the following conditions:

• For patients who were erroneously randomized (screening failures) and did not get IMP treatment.

• For patients who were randomized but consent was withdrawn (either by the patient or patient representative) within the first 48 hours after randomization, irrespective of whether IMP was administered or not.

The primary statistical analysis will be based on all randomized patients except patients randomized in error who did not get IMP treatment.

In Phase III, patients will be treated with a maximum of 6 IV doses of IFX-1 800 mg (Arm A) or placebo (Arm B) at days 1, 2, 4, 8, 15, and 22, as long as the patient is still in the hospital (even if discharged from the ICU).

Patients will be assessed for quality of life using the EQ-5D.

Patients will be followed for survival and their clinical status assessed by the Glasgow Outcome Scale.

End of Treatment and Follow-up

End of treatment (EOT) is defined as the last planned administration or discontinuation of IMP for other reasons. The FUV is scheduled to occur 28 days (if patient has been discharged) and 60 days after the randomization date. The visit information obtained at a site visit or via telephone call (e.g., AEs, survival status, according to the SoA) should be recorded.

Discontinuation of study treatment does not represent withdrawal from the study.

End of Study

The end of study for the individual patient is defined as the date of the last contact of the follow up period (i.e., 60 days after randomization), date of death, date of consent withdrawal from study participation, or the date of last contact when patients are lost to followup, whatever occurs earliest.

The entire study will end when all patients have discontinued IFX 1 AND all patients ended the study as described above.

D) Study population

Inclusion criteria

Patients must meet all the following criteria at randomization to be enrolled into Phase III of the study:

1. At least 18 years of age or older

2. Patient on invasive mechanical ventilation (but not more than 48h post intubation at time point of first IMP administration)

3. Patients with a PaCh / FiCh ratio of < 200 and > 60 at randomization (one representative measurement within 6h before randomization)

4. SARS-CoV-2 infection confirmation (tested positive in last 14 days before randomization with locally available test system)

Exclusion criteria

Patients who fulfill any of the following criteria at randomization are not eligible to participate in Phase III of the study:

1. Intubated > 48 h at time point of first IMP administration

2. Expected stop of invasive ventilation or expected extubation in the next 24h without additional intervention according to judgment of the investigator

3. Known history of chronic dialysis OR received renal replacement therapy in past 14 days OR anticipated to receive renal replacement therapy within 24h after randomization 4. Known history of progressed COPD as evidenced by use of daily maintenance treatment with long-acting bronchodilators or inhaled/oral corticosteroids for > 2 months

5. Treatment of COVID-19 with investigational antibody treatment(s) which are not approved or not included in locally adopted treatment guidelines (e.g., WHO guidance, National Institutes of Health [NIH] CO VID-19 treatment guidelines) for this indication in the past 7 days (Note: Antibody treatments] given within past 7 days for pre existing diseases, other than COVID-19, are allowed.)

6. At time point of randomization, treatment of COVID 19 with investigational treatments which are not approved or not included in locally adopted treatment guidelines for this indication (e.g., WHO guidance, NIH COVID-19 treatment guidelines), including SARS CoV-2 multiplication inhibitor(s) or immunomodulator(s). (Note: If a locally adopted treatment guideline recommends drugs such as remdesivir, dexamethasone, or anticoagulation, this would be allowed. Adopted guidelines and updates must be documented at study initiation and throughout the conduct of the study.)

7. Received cytokine adsorption therapy in past 3 days

8. Known hypersensitivity to IFX-1 or any other ingredient of the study medication

9. Serum or urine pregnancy test positive before randomization (required for women of childbearing potential)

10. Received organ or bone marrow transplantation in past 3 months

11. Known cardio-pulmonary mechanical resuscitation in past 14 days

12. Patient moribund or expected to die in next 24h according to the judgment of the investigator

13. Known to have received anti-cancer therapy for hemato-oncological disease in past 4 weeks OR known to have active malignant disease at time point of randomization

14. Known severe congestive heart failure (corresponding to e.g. NYHA Class III- IV, left ventricular ejection fraction <40%; see Appendix 8)

15. Known history of chronic liver disease (Child-Pugh B or C; see Appendix 11)

16. Participating in or has participated in other investigational interventional studies (drug or device) within the last 7 days before randomization

Screen failures Screening failures are defined as patients who do not meet the criteria for participation in this study and thus, are either not randomized/assigned to IMP or randomized in error and do/did not receive IMP. Screen failure data for not randomized patients will not be recorded in the eCRF, for those patients who are randomized in error, screen failure data are to be recorded in the eCRF.

Rescreening does not apply to this study.

E) Study intervention

Investigational medicinal product (IMP)

The IMP is defined as the investigational treatment IFX-1 and Placebo-to-match (Placebo) that is intended to be administered to a study patient according to the study protocol.

IFX-1 concentrate solution for infusion will be supplied in 20 mL glass vials at a concentration of 10 mg/mL (200 mg per vial) for reconstitution and IV administration. Apart from IFX 1, the solution will contain sodium chloride, sodium phosphate, and polysorbate 80.

Placebo concentrate solution for infusion will be supplied in 20 mL glass vials for reconstitution and IV administration. The solution will contain sodium chloride, sodium phosphate, and polysorbate 80.

Administration and Dosage

For Phase III, patients are randomized to either receive SOC + IFX-1 in treatment Arm A or SOC + Placebo in treatment Arm B. The first dose of IFX-1 or Placebo is administered at Day 1. SOC may start at any time according to their administration schedule.

Close observation of IFX-1 or Placebo infusion(s) is required for monitoring of potential infusion reactions. Appropriate treatment for potential infusion reactions must be available during this time.

Patients will be treated with a maximum of 6 IV doses of IFX-1 800 mg (Arm A) or placebo (Arm B) administered as a 30-60-minute IV infusion. The 6 treatments are at days 1, 2, 4, 8, 15, and 22 as long as the patient is still in the hospital, even if discharged from ICU. IMP administrations for Phase III are detailed in Figure 1.

Prior and Concomitant Medication/Treatments

In Phase III of the study, in addition to the IMP, all patients will receive SOC for treatment of COVID-19, which includes VTE prophylaxis with anticoagulants at a minimum. Other international or country-specific recommended treatments for COVID-19 per the locally adopted treatment recommendations (including but not limited to corticosteroids, remdesivir, and other local SOC) are allowed as concomitant medications. SOC treatment start and stop is not defined by the protocol and can start at any time. SOC treatment will be given according to investigator’s discretion.

Reportable medications or vaccinations that the patient is receiving within 7 days prior to randomization and up to 30 days after the last dose of study treatment should be recorded along with:

• Reason for use

• Dates of administration including start and end dates

F) Study assessments and procedures

Baseline Assessments (Screening)

The following procedures will be performed to assess baseline characteristics during screening evaluations and before randomization and IMP administration:

• Check inclusion and exclusion criteria

• Documentation of demographic details (age, gender, race, and ethnicity), medical and COVID- 19 history. Race information is required for eGFR calculation using the CKD-EPI equation

• 8-point ordinal scale assessment and oxygenation index (PaO? / FiO?; one representative measurement within 6h before randomization)

• Documentation of concomitant disease and prior medications

• Baseline safety assessment (height, weight, physical exam, AEs, ECG, urine analysis, pregnancy test, and clinical safety laboratory [including creatinine assessment]))

Prior and Concomitant Medications and Procedures

All procedures performed or medications administered within 7 days before randomization should be recorded as prior procedures and prior medication with generic name, start date, stop date, and indication for treatment.

Reporting of prior and concomitant medications will follow special considerations for conditions in the ICU. A complete record of all prior and concomitant medications (but excluding nutritional and volume therapy, electrolyte support, vitamins, non-steroidal antiinflammatory drugs (NSAIDs), and supportive therapies such as artificial tears, ointments, stool softeners/laxatives, etc.) will be maintained in the eCRF for each participant, beginning 7 days before randomization and continuing up to 30 days after the last dose of study treatment).

In addition, a complete record of all steroid and antibiotic therapy, as well as any therapy (medications, specific treatments, etc.) associated with or used in the assessment or treatment of an AE will be documented for the duration of the study.

The following information must be recorded in the eCRF for each reportable concomitant medication: generic name, route of administration, start date, stop date, and indication

G) Adverse events

Definition of adverse events (AE):

An AE is any untoward medical occurrence in a subject administered an IMP; an AE does not necessarily have to have a causal relationship with this treatment.

AEs encompass any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease that arises or worsens after the inclusion of the subject into the study.

H) Statistical considerations

Determination of sample size

A total of 180 patients (90 per arm) are planned to be randomized in Stage 1 and up to 180 patients (90 per arm) in Stage 2. For patients randomized in error (screening failures) and patients for whom consent is withdrawn within 48 hours after randomization, additional patients will be randomized. This results in 90% overall power to show efficacy in the final efficacy analysis. The power calculation is based on an overall 2.5% one-sided alpha and an assumed 30% 28-day mortality under Placebo and 15% 28-day mortality under IFX-1 treatment.

Analysis sets

Full analysis set (FAS): The primary statistical analysis will be based on all randomized patients except patients randomized in error (reason for early termination documented as “Randomized by mistake” in the eCRF) who did not get IMP treatment.

Safety analysis set (SAF): Safety analyses will be based on all patients who received at least one infusion of IMP, and patients will be analyzed according to the treatment they actually received. Statistical Analyses

Primary Efficacy Analysis

The primary analysis will be performed based on the FAS.

The primary efficacy variable is 28-day mortality (proportion of patients deceased until day 28). The primary statistical hypotheses to be tested are:

Ho: HR = 1 versus

Hi: HR > 1 where HR is the hazard ratio derived from the beta coefficient of the primary statistical analysis Cox regression model comparing the SOC + Placebo treatment arm (Arm B) with the SOC + IFX-1 treatment arm (Arm A).

A total of 180 patients are planned to be randomized to Arm A and Arm B using a 1 : 1 allocation ratio for the first stage. The interim analysis is performed after 180 patients, not counting patients being randomized in error, have been followed-up until day 28 (or died before). In case the interim analysis does not result in an early stop for futility, 180 additional patients are planned to be randomized in a ratio of 1 : 1 to Arm A and B. The planned maximum number of patients in the study is 360. Depending on the number of patients meeting criteria for additional randomization, more patients will be randomized but not more than 400.

The primary statistical analysis of IFX-1 + SOC compared to SOC alone will make use of a one-sided alpha level of 2.5% and will test for superiority (lower mortality among IFX-1 treated patients). The primary statistical analysis will be based on a Cox proportional hazards regression model with outcome 28-day all-cause mortality as a censored time-to-event variable and explanatory variables treatment arm (Arm B versus Arm A) and age. The primary statistical analysis will be based on all randomized patients except patients randomized in error (reason for early termination documented as “Randomized by mistake” in the eCRF) who did not get IMP treatment. For the primary analysis, all-cause mortality will be censored at day 28 for subjects who died after day 28 or who have more than 28 days follow-up alive.

The z-statistic for the interim and final analysis will be calculated as the proportion of the beta coefficient for the treatment arm effect and its standard error from the Cox proportional hazards regression model. The study will be stopped for futility if the z-statistic for the first stage is 0 or lower. Secondary Efficacy Analysis

The secondary efficacy analyses will be performed based on the FAS.

The first secondary efficacy endpoint will only be addressed with statistical hypothesis tests if the primary endpoint is statistically significant using the full overall 2.5% one-sided alpha. If the first secondary endpoint is also statistically significant, the full 2.5% one-sided alpha will be passed to the 4 remaining secondary endpoints. Multiplicity in the secondary endpoints will be addressed with the fallback method. 60-day mortality will be analyzed similar to 28-day mortality and the other secondary endpoints will be evaluated using a logistic regression model with the explanatory variables randomized treatment arm (Arm B versus Arm A) and age for:

1. 60-day all-cause mortality

2. Proportion of patients with an improvement in the provided 8-point ordinal scale at day 15 (at least one score point lower than at randomization)

3. Proportion of patients with an improvement in the provided 8-point ordinal scale at day 28 (at least one score point lower than at randomization)

4. Proportion of patients developing acute kidney failure (eGFR < 15 mL/min/1.73m²) during ICU stay and at day 28

5. Proportion of patients free of any renal replacement therapy within 28 days upon randomization

The ordering of the secondary endpoints 2 to 5 for hypothesis testing will be as in above mentioned list. The full 2.5% one-sided alpha for the fallback method will be attributed to the 4 secondary endpoints in the following way 2%, 0.2%, 0.2%, and 0.1%. If the preceding hypothesis test is not significant, subsequent tests will be performed at the aforementioned alpha level. If tests are significant, the alpha is added to the subsequent hypothesis test (e.g., if the primary hypothesis test is significant and secondary endpoints 1-4 are all significant, the fifth secondary endpoint will be tested at an alpha of 2.5%; if the fourth secondary endpoint is not significant, the fifth secondary endpoint will be tested at an alpha of 0.1%).

The primary endpoint as well as all secondary endpoints will also be evaluated as censored time to event variables by Kaplan-Meier type methods. Kaplan-Meier analyses will be performed comparing the two treatment arms overall and within the following stratifications:

• Stratification by site

• Stratification by country

• Stratification by sex

• Stratification by age Stratification by comorbidities

Stratification by standard or care.

Other Efficacy Analyses

Time to First Extubation

Time to first extubation will be analyzed as a censored time to event variable. Withdrawing early from the study will lead to the patient being right-censored at the date of withdrawal provided that the reason is not an outcome of interest (extubation or death). In order to adequately account for competing outcomes as well as potential right-censoring due to varying follow-up times, the outcome will be non-parametrically analyzed using Aalen- Johansen-type estimation based on a competing risks model with two absorbing states (event 1 : all-cause death; event 2: extubation). Adjustment for age will be realized by regression modeling accounting for competing risks.

Patients Alive and Free of Respiratory Failure

Patients achieving 8-point ordinal scale score 3 or below (patients alive and free of respiratory failure) at day 15 and day 28 are defined as alive and free of respiratory failure at the respective study day. The corresponding endpoint will be analyzed using logistic regression with explanatory variables age and treatment group.

Glasgow Outcome Scale

Glasgow Outcome Scale assessed at study day 60 will be analyzed via ordinal logistic regression with explanatory variables treatment arm (Arm B versus Arm A) and age.

Quality of Life

Quality of life will be assessed by EQ-5D at study day 60. The visual analogue scale as well as an index value based on the 5 health states (cross-walk index value using the United States value set) will be analyzed by an ANCOVA model with explanatory variables treatment arm (Arm B versus Arm A), age, and sex (male versus female).

Interim Analysis

The interim analysis is performed after the first 180 patients, not counting patients being randomized in error, in Stage 1 have been followed-up until day 28 (or died before). The study will be stopped for futility if the z-statistic of the primary efficacy analysis is 0 or lower. If the study is not stopped for futility, another up to 180 patients will be randomized in Stage 2. Depending on the number of patients meeting criteria for additional randomization, more than 360 patients will be randomized but not more than a total of 400.

Example 2: Patients receiving combined treatment of IFX-1 and Tocilizumab in Phase III study evaluating IFX-1 for the treatment of COVID 19 related severe pneumonia

A) Prior or concomitant use of Tocilizumab

Some patients enrolled in the phase III trial outlined in example 1 above where also receiving the anti-IL-6 receptor antibody Tocilizumab, which had received an emergency use authorization by the FDA and EMA for the treatment of severe COVID-19.

Unexpectedly, patients receiving both medications, i.e. IFX-1 (vilobelimab) and tocilizumab, exhibited a highly significant reduction of all-cause mortality as compared to placebo treatment as well as single use of vilobelimab or tocilizumab.

This significant reduction was observed in patients receiving tocilizumab prior to first administration of vilobelimab (i.e. tocilizumab baseline use) as well as concomitant use of both compounds.

For the purpose of the present application the following definitions of baseline use and concomitant use will be used

Baseline use of tocilizumab is defined as receiving at least one dose of tocilizumab between study day -7 and study day 1.

Prior use of tocilizumab is defined as receiving at least one dose of tocilizumab before day-7 (i.e. prior to baseline use) concomitant use: Medications will be counted as concomitant either

• if they have an end date/time later than the timestamp of randomization

• or if “ongoing' is ticked on the respective eCRF page.

If the end date/time is completely missing and “ongoing” is not ticked, the previous medication will also be assumed to be concomitant. Incomplete start/end dates will not be imputed. If the incomplete date does not allow clear categorization as previous or concomitant medication, the medication will be counted as concomitant.

For the Cox proportional hazard models and Kaplan-Meier curves reported herein tocilizumab use is either classified as ‘baseline usage of Tocilizumab’ or ‘any usage of Tocilizumab’, whereas the later encompasses prior use, baseline use and concomitant use. B) Effect of combined treatment with an inhibitor of C5a activity and an inhibitor of IL-6 activity

The primary statistical analysis is based on a Cox proportional hazards regression model with outcome 28-day and 60-day all-cause mortality as a censored time-to-event variable and explanatory variables treatment arm (Arm B (i.e. placebo + SOC) versus Arm A (i.e. vilobelimab + SOC) and age. This statistical analysis was made with patients receiving Tocilizumab (baseline use or any use) in Arm A and or Arm B.

Of note, a hazard ratio (HR) above 1 indicates a covariate that is positively associated with the event probability, and thus negatively associated with the length of survival. In summary, HR = 1 : No effect, HR < 1 : Reduction in the hazard and HR > 1 : Increase in Hazard. Therefore a covariate with a hazard ratio > 1 is a bad prognostic factor and a covariate with a hazard ratio < 1 is called good prognostic factor.

Combined treatment vilobelimab and tocilizumab (any usage)

As shown in Table 2 below, the 28-day all-cause-mortality for patients receiving vilobelimab and tocilizumab (any usage) is significantly reduced as compared to the placebo group (i.e. tocilizumab any usage) (p=0.0098, HR: 0.140). In other words, the combined treatment of vilobelimab and tocilizumab (any usage) is significantly more effective in reducing all cause mortality as compared to tocilizumab alone. All treatment group received in addition to the indicated treatment also standard of care (SOC).

Table 2: Cox proportional hazard model for 28-day all-cause mortality for patients with any usage of Tocilizumab - FAS; (number of patients in analysis set/model: 61/61)

* Wald-type confidence intervals; HR = Hazard Ratio; FAS = Full analysis set; SOC = Standard of care; Vilo = Vilobelimab

The same significant reduction is observed for 60-day all-cause mortality as shown in Table 3 below. The treatment group receiving vilobelimab and tocilizumab (any usage) had a significantly reduced all-cause mortality as compared with the placebo group (i.e. tocilizumab any usage) (p=0.0187; HR: 0.296).

Table 3: Cox proportional hazard model for 60-day all-cause mortality for patients with any usage of Tocilizumab - FAS; (number of patients in analysis set/model: 61/61)

Combined treatment vilobelimab and tocilizumab (baseline usage)

A similar effect was observed for baseline usage of Tocilizumab (defined as receiving at least one dose of tocilizumab between study day -7 and study day 1).

The 28-day all-cause mortality was dramatically reduced if the patients received baseline usage of Tocilizumab in combination with vilobelimab as indicated by the hazard ratio of 0.0.073 (p=0.012; see Table 4 below).

Table 4: Cox proportional hazard model for 28-day all-cause mortality for patients with baseline usage of Tocilizumab - FAS; (number of patients in analysis set/model: 60/60);

A similar effect was observed for 60-day all-cause mortality after Tocilizumab baseline usage. The all-cause mortality was dramatically reduced as indicated by the hazard ratio of 0.245 (p=0.0127; see Table 5 below).

Table 5: Cox proportional hazard model for 60-day all-cause mortality for patients with baseline usage of Tocilizumab - FAS; (number of patients in analysis set/model: 60/60) * Wald-type confidence intervals; HR = Hazard Ratio; FAS = Full analysis set; SOC = Standard of care; Vilo = Vilobelimab

Treatment with vilobelimab without any usage of tocilizumab

Patients treated with vilobelimab alone also had a reduced 28-day all-cause mortality as compared to placebo (no tocilizumab use). However, the effect, as indicated by the hazard ratio of 0.793, was much smaller than the combination of vilobelimab and tocilizumab (HR=0.140).

Table 6: Cox proportional hazard model for 28-day all-cause mortality for patients without any usage of Tocilizumab - FAS; (number of patients in analysis set/model: 307/307) * Wald-type confidence intervals; HR = Hazard Ratio; FAS = Full analysis set; SOC = Standard of care; Vilo = Vilobelimab

The same was observed for 60-day all-cause mortality. Here all-cause mortality was also reduced, but with a similar hazard ratio of 0.756 (see Table 7 below) as compared to the combination of vilobelimab and tocilizumab (HR=0.296).

Table 7: Cox proportional hazard model for 60-day all-cause mortality for patients without any usage of Tocilizumab - FAS; (number of patients in analysis set/model: 61/61) * Wald-type confidence intervals; HR = Hazard Ratio; FAS = Full analysis set; SOC = Standard of care; Vilo = Vilobelimab Essentially the same result was achieved in the treatment group not receiving baseline usage of Tocilizumab. For the sake of clarity, these group of patients (i.e. no baseline use of Tocilizumab) did not receive any Tocilizumab administration (neither baseline nor any other use), but rather vilobelimab or placebo treatment. The all-cause mortality for 28-days and 60- days was reduced by vilobelimab treatment as indicated by the hazard ratios of 0.801 and 0.763 respectively (see Tables 8 and 9 below).

Table 8: Cox proportional hazard model for 28-day all-cause mortality for patients without baseline usage of Tocilizumab - FAS; (number of patients in analysis set/model: 308/308)

Table 9: Cox proportional hazard model for 60-day all-cause mortality for patients without baseline usage of Tocilizumab - FAS; (number of patients in analysis set/model: 308/308)

Baseline usage of tocilizumab and interaction with vilobelimab treatment

Further Cox proportional hazard models as a censored time-to-event variable and explanatory variables treatment arm and age and baseline tocilizumab use flag and its interaction with study treatment were established.

In a first analysis the 28-day all-cause mortality with baseline tocilizumab was investigated. As indicated in table 10 below, treatment with vilobelimab alone (i.e. “Treatment (Vilo vs Placebo) for baseline tocilizumab use: no") had only a small effect on 28 day survival rate with a HR of 0.797. Likewise the baseline use of tocilizumab without vilobelimab ('Baseline Tocilizumab use (yes vs no) for Treatment: Placebo") had a minor effect on survival rate with a HR of 0.844. In contrast the interaction of vilobelimab treatment with baseline use of tocilizumab ^Treatment (Vilo vs Placebo) for baseline tocilizumab use: yes”) resulted in a robust effect on survival with a HR of only 0.073. Consistently, the same robust effect on survival was observed for baseline Tocilizumab use interaction with vilobelimab treatment with a HR of 0.077. Taken together the combined treatment of vilobelimab and baseline tocilizumab resulted in a dramatic increase of survival whereas the treatment with vilobelimab or tocilizumab alone only had a minor effect.

Table 10: Cox proportional hazards regression model with outcome 28-day all-cause mortality as a censored time-to-event variable and explanatory variables treatment arm and age and baseline tocilizumab use flag and its interaction with study treatment - FAS. (number of patients in analysis set/model: 368/368)

As similar effect of the respective treatments was observed for 60-day all-cause mortality as summarized in Table 11 below.

Table 11: Cox proportional hazards regression model with outcome 60-day all-cause mortality as a censored time-to-event variable and explanatory variables treatment arm and age and baseline tocilizumab use flag and its interaction with study treatment - FAS. (number of patients in analysis set/model: 368/368)

Any usage of tocilizumab and interaction with vilobelimab treatment

The statistical analysis including interaction of the different treatments for any usage of Tocilizumab on 28-day all-cause mortality had a similar result as disclosed above for baseline usage of Tocilizumab (see Table 12 below). The treatment with only vilobelimab ‘Treatment (Vilo vs Placebo) for any tocilizumab use: no had in this group of patient"") had in this group of patients a minor effect as indicated by a HR of 0.789. Likewise treatment with only tocilizumab (any usage) ( ny Tocilizumab use (yes vs no) for Treatment: Placebo’"') had a minor effect as indicated by a HR of 0.844.

In contrast and consistent with the observation for baseline usage of Tocilizumab the interaction of vilobelimab treatment with baseline use of tocilizumab (‘Treatment (Vilo vs Placebo) for any tocilizumab use: yes’" resulted in a robust effect on survival with a HR of only 0.249. Consistently, the same robust effect on survival was observed for any Tocilizumab use interaction with vilobelimab treatment with a HR of 0.276.

Table 12: Cox proportional hazards regression model with outcome 28-day all-cause mortality as a censored time-to-event variable and explanatory variables treatment arm and age and any tocilizumab use flag and its interaction with study treatment - FAS. (number of patients in analysis set/model: 368/368)

A virtually identical result was observed for 60-day all-cause mortality as disclosed in Table 13 below.

Table 13: Cox proportional hazards regression model with outcome 60-day all-cause mortality as a censored time-to-event variable and explanatory variables treatment arm and age and any tocilizumab use flag and its interaction with study treatment - FAS. (number of patients in analysis set/model: 368/368)

C) Effect of combined treatment of vilobelimab and tocilizumab on patient survival

In addition to the statistical analysis using Cox proportional hazard model the single and combined treatment of vilobelimab and tocilizumab was also analyzed with the Kaplan-Meier method. This is a non-parametric method used to estimate the survival probability from observed survival times and is typically plotted as Kaplan-Meier survival graphs.

The effect size of combined treatment of vilobelimab and tocilizumab (any usage) on all-cause mortality is dramatically increased as can be seen in figure 2. Treatment of vilobelimab combined with any usage of tocilizumab (line 1) shows only a slight increase of the probability of mortality within 60 days. In comparison, the group receiving placebo without any use of Tocilizumab (line 4) had a much higher mortality rate. The mortality rate in the groups receiving vilobelimab and standard of care (SOC) without tocilizumab (line 2) showed only a slight improvement. Patients treated with tocilizumab and SOC (line 3) showed an even lower improvement of survival rates. A virtually identical outcome was observed with baseline use of Tocilizumab (see figure 3).

The benefit of combined vilobelimab and tocilizumab treatment is even more pronounced within the first 22 days of treatment with hardly any fatalities in this treatment group. In contrast in the other treatment groups the majority of fatalities occurred in this time of treatment.

In summary, the combined treatment of vilobelimab and tocilizumab (baseline use and any use) resulted in a dramatic increase of survival probability as compared to the treatment with only one of the compounds or placebo. Of note the effect on survival rate of the combined treatment is much higher than the sum of the individual effects of vilobelimab and tocilizumab alone, indicating a synergistic effect of the combined treatment instead of a mere additive effect.

Claims

1. An inhibitor of C5a activity for use in:

2. An inhibitor of IL-6 activity for use in:

3. The inhibitor of C5a activity or the inhibitor of IL-6 activity for use according to claim 1 or 2, wherein the inhibitor of IL-6 activity binds specifically to IL-6 or the IL-6 receptor (IL-6R), preferably comprises a protein ligand.

4. The inhibitor of C5a activity or the inhibitor of IL-6 activity for use according to any one of the previous claims, wherein the inhibitor of C5a activity binds specifically to C5a or to the C5a receptor (C5aR), preferably comprises:

(i) a protein ligand specifically binding to C5a or the C5aR, preferably specifically binding to C5a

(ii) a small molecule C5aR antagonist, preferably according to general formula (I).

5. The inhibitor of C5a activity or the inhibitor of IL-6 activity for use according to claim

3 or 4, wherein the protein ligand is:

(i) an antibody or an antigen binding fragment thereof, preferably the protein ligand comprises a VH and a VL domain of an antibody, a Fab fragment, a Fab’ fragment, a heavy chain antibody, a single-domain antibody (sdAb), variable domain of a heavy chain antibody, a VHH, a nanobody, a single-chain variable fragment (scFv), a tandem scFv, or a single-chain diabody; (ii) an antibody-like protein, preferably an affibody, anticalin, or an designed ankyrin repeat protein;

(iii) an inhibitory variant of C5a; or

(iv) an inhibitory variant of C5a receptor.

6. The inhibitor of C5a activity or the inhibitor of IL-6 activity for use according to claim 4 or 5 , wherein the protein ligand specifically binding to C5a binds to a conformational epitope of C5a formed by amino acid sequences NDETCEQRA (SEQ ID NO: 2) and SHKDMQL (SEQ ID NO: 3), and binds to at least one amino acid within the amino acid sequence according to SEQ ID NO: 2 and to at least one amino acid within the amino acid sequence according to SEQ ID NO: 3, wherein the specific binding to the amino acids of the conformational epitope is determined by alanine scanning.

7. The inhibitor of C5a activity or the inhibitor of IL-6 activity for use according to claim 6, wherein the protein ligand specifically binding to C5a is an antibody or antigenbinding fragment thereof that: binds to at least one amino acid of an amino acid sequence according to DETCEQR (SEQ ID NO: 4); and/or binds to at least one amino acid of an amino acid sequence according to HKDMQ (SEQ ID NO: 5), preferably to KDM.

8. The inhibitor of C5a activity or the inhibitor of IL-6 activity for use according to any one of claims 4 to 7, wherein the protein ligand specifically binding to C5a is an antibody or antigen-binding fragment thereof comprising a variable domain of a heavy chain (VH) and a variable domain of a light chain (VL), wherein the VL comprises:

(i) a light chain CDR3 sequence as set forth in SEQ ID NO: 6; or

(ii) a light chain CDR3 sequence as set forth in SEQ ID NO: 7; wherein said antibody or antigen-binding fragment thereof has a binding constant to C5a with a Ka value of 10 nM or less and exhibits at least 80% blocking activity for a biological effect induced by C5a, optionally the VL further comprises a FR2 region as set forth in SEQ ID NO: 8 or SEQ ID NO: 39.

9. The inhibitor of C5a activity or the inhibitor of IL-6 activity for use according to claim 8, wherein the protein ligand specifically binding to C5a further comprises at least one of the following sequences:

(i) a heavy chain CDR2 sequence according to SEQ ID NO: 9;

(ii) a heavy chain CDR2 sequence according to SEQ ID NO: 10;

(iii) a light chain CDR2 sequence according to SEQ ID NO: 11;

(iv) a light chain CDR2 sequence according to SEQ ID NO: 12;

(v) a heavy chain CDR1 sequence according to SEQ ID NO: 13;

(vi) a heavy chain CDR1 sequence according to SEQ ID NO: 14;

(vii) a light chain CDR1 sequence according to SEQ ID NO: 15;

(viii) a light chain CDR1 sequence according to SEQ ID NO: 16;

(ix) a heavy chain CDR3 sequence according to SEQ ID NO: 17; or

(x) a heavy chain CDR3 sequence according to SEQ ID NO: 18.

10. The inhibitor of C5a activity or the inhibitor of IL-6 activity for use according to any one of claims 4 to 9, wherein the protein ligand specifically binding to C5a comprises:

(i) a light chain CDR3 sequence according to SEQ ID NO: 6, a light chain CDR2 sequence according to SEQ ID NO: 11, a light chain CDR1 sequence according to SEQ ID NO: 15, a heavy chain CDR3 sequence according to SEQ ID NO: 17, a heavy chain CDR2 sequence according to SEQ ID NO: 9, and a heavy chain CDR1 sequence according to SEQ ID NO: 13; or

(ii) a light chain CDR3 sequence according to SEQ ID NO: 7, a light chain CDR2 sequence according to SEQ ID NO: 12, and a light chain CDR1 sequence according to SEQ ID NO: 16, a heavy chain CDR3 sequence according to SEQ ID NO: 18, a heavy chain CDR2 sequence according to SEQ ID NO: 10, and a heavy chain CDR1 sequence according to SEQ ID NO: 14.

11. The inhibitor of C5a activity or the inhibitor of IL-6 activity for use according to any one of claims 4 to 10, wherein the protein ligand specifically binding to C5a is selected from the group consisting of:

(a) IFX-1 (vilobelimab), IFX-2, INab708, BNJ364, BNJ367, BNJ371, BNJ378, BNJ366, BNJ369, BNJ381, BNJ383, MEDL7814 or ALXN-1007, or an antigen-binding fragment thereof; or (b) an antibody or an antigen-binding fragment thereof, wherein said antibody or antigen-binding fragment thereof competes with one of the antibodies indicated under (a) for binding to C5a.

12. The inhibitor of C5a activity or the inhibitor of IL-6 activity for use according to any one of claims 3 to 11, wherein:

(a) the protein ligand specifically binding to IL-6R is selected from Tocilizumab, Sarilumab, Levilimab, and Vobarilizumab; more preferably wherein the inhibitor of IL-6 activity is Tocilizumab; or

(b) the protein ligand specifically binding to IL-6 is selected from Siltuximab, Sirukumab, Olokizumab, Elsilimomab, Clazakinumab, PF-423691 and EBI- 031.

13. The inhibitor of C5a activity or the inhibitor of IL-6 activity for use according to any one of the previous claims, wherein

(a) the infectious pneumonia is selected from viral pneumonia, fungal pneumonia or bacterial pneumonia, preferably CO VID-19 pneumonia; and/or

(b) the infectious ARDS is selected from viral ARDS and bacterial ARDS; preferably COVID-19 ARDS.

14. The inhibitor of C5a activity or the inhibitor of IL-6 activity for use according to any one of the previous claims, wherein the inhibitor of C5a activity is vilobelimab and the inhibitor of IL-6 activity is tocilizumab.

15. The inhibitor of C5a activity or the inhibitor of IL-6 activity for use according to any one of the previous claims, for administration in a regime comprising an induction phase followed by a maintenance phase, wherein the inhibitor of C5a activity is administered in the induction phase and the maintenance phase and the inhibitor of IL-6 activity is administered:

(I) within 0-30 days prior to the induction phase,

(II) during the induction phase, and/or

(III) during the maintenance phase.

16. The inhibitor of C5a activity and the inhibitor of IL-6 activity for use according to claim 15, wherein

(i) the induction phase comprises or essentially consists of a period of 1 to 10 days, preferably 2 to 8 days, more preferably 7-8 days, wherein 1-8 doses, preferably 2-4 doses, comprising each 200-1600 mg, preferably 400-1200 mg of said inhibitor of C5a activity, are administered; and

(ii) the maintenance phase comprises or essentially consists of a period of at least 2 weeks, preferably 2-4 weeks, wherein a dose, comprising 200-1600 mg, preferably 400-1200 mg of said inhibitor of C5a activity, is administered every 1-4 weeks, preferably every week; preferably the inhibitor of IL-6 activity is administered at a weight dependent dose of 8mg/kg for patients at or above 30 kg weight or 12 mg/kg for patients of less than 30 kg weight.

17. The inhibitor of C5a activity and the inhibitor of IL-6 activity for use according to any one of claims 15 and 16, wherein

(i) 1 or 2 doses (preferably single dose) of the inhibitor of IL-6 activity (preferably tocilizumab) is administered within 0 to 14 days prior and/or after the start of the induction phase (preferably within 0 to 7 days prior or after the start of the induction phase); and/or

(ii) the inhibitor of IL-6 activity (preferably tocilizumab) is administered at a weight dependent dose of 8mg/kg for patients at or above 30 kg weight or 12 mg/kg for patients of less than 30 kg weight.

18. A kit of parts comprising an inhibitor of C5a activity, preferably vilobelimab, and an inhibitor of IL-6 activity, preferably tocilizumab.