Regional Centres Thomas Sitter; University of Würzburg: Vera Krane, Daniel

RWTH Aachen University: Georg Schlieper, Frank Eitner, Schmiedeke, Sebastian Toncar, Christoph Wanner.
Sabine Meisen, Katharina Kehl, Elfriede Arweiler, Jürgen Analytical Centres
Floege; Charité, University Medicine Berlin: Elke Schaeffner, University of Erlangen-Nürnberg, Institute of Human Gen-
Seema Baid-Agrawal, Ralf Schindler; University of Erlangen- etics: Arif B. Ekici, André Reis; Innsbruck Medical University,
Nürnberg: Stephanie Titze, Silvia Hübner, Thomas Diene- Division of Genetic Epidemiology: Lukas Forer, Sebastian
mann, Karl F. Hilgers, Kai-Uwe Eckardt; University of Freiburg: Schönherr, Hansi Weissensteiner, Barbara Kollertits, Julia
Anna Köttgen, Ulla Schultheiß, Gerd Walz; Hannover Medical Raschenberger, Florian Kronenberg; University of Regensburg,
School: Jan T. Kielstein, Johan Lorenzen, Hermann Haller; Institute of Functional Genomics: Wolfram Gronwald, Helena
University of Heidelberg: Claudia Sommerer, Martin Zeier; Zacharias, Peter Oefner.
University of Jena: Martin Busch, Katharina Paul, Gunter Wolf;
Ludwig-Maximilians University of München: Robert Hilge, Received for publication: 12.7.2014; Accepted in revised form: 8.8.2014

Nephrol Dial Transplant (2015) 30: 451–460

doi: 10.1093/ndt/gfu297
Advance Access publication 19 September 2014

Incidence of erythropoietin antibody-mediated pure

red cell aplasia: the Prospective Immunogenicity Surveillance

ORIGINAL ARTICLE
Registry (PRIMS)

Iain C. Macdougall1, Nicole Casadevall2, Francesco Locatelli3, Christian Combe4, Gerard M. London5,
Salvatore Di Paolo6, Andreas Kribben7, Danilo Fliser8, Hans Messner9, John McNeil10, Paul Stevens11,
Antonio Santoro12, Angel L.M. De Francisco13, Paul Percheson14, Anna Potamianou14, Arnaud Foucher14,
Daniel Fife14, Véronique Mérit14 and Els Vercammen14on behalf of the PRIMS study group
1
Department of Renal Medicine, King’s College Hospital, London, UK, 2Service d’Immunologie et Hématologie Biologiques, Hôpital Saint
Antoine, Paris, France, 3Division of Nephrology and Dialysis, Alessandro Manzoni Hospital, Lecco, Italy, 4Service de Néphrologie, Centre
Hospitalier Universitaire de Bordeaux and Unité INSERM 1026, Université de Bordeaux, Bordeaux, France, 5Centre de Recherche des
Cordelliers, Ecole de Médecine, Paris, France, 6Division of Nephrology and Dialysis, Hospital ‘Dimiccoli’, Barletta, Italy, 7Klinik für
Nephrologie, Universitätsklinik Essen, Essen, Germany, 8Department Internal Medicine IV, Universitätsklinik Homburg/Saar, Homburg/Saar,
Germany, 9Department of Medical Biophysics, University of Toronto, Toronto, Canada, 10Department of Epidemiology and Preventive
Medicine, Monash University Melbourne, Melbourne, Australia, 11Department of Renal Medicine, Kent and Canterbury Hospital, Canterbury,
UK, 12Dialysis and Hypertension Department, Azienda Ospedaliero-Universitaria di Bologna, Policlinico S Orsola-Malpighi, Bologna, Italy,
13
Nephrology Department, Hospital Universitario Valdecilla, Santander, Spain and 14Janssen, Pharmaceutical Companies of Johnson &
Johnson, Titusville, NJ, USA

Correspondence and offprint requests to: Iain C. Macdougall; E-mail: iain.macdougall@nhs.net

A B S T R AC T increased reports of anti-erythropoietin antibody-mediated pure

red cell aplasia (PRCA). The Prospective Immunogenicity Surveil-
Background. Subcutaneous administration of Eprex® (epoetin lance Registry (PRIMS) was conducted to estimate the incidence
alfa) in patients with chronic kidney disease (CKD) was contrain- of antibody-mediated PRCA with subcutaneous administration of
dicated in the European Union between 2002 and 2006 after a new coated-stopper syringe presentation of Eprex® and to
compare this with the PRCA incidence with subcutaneous NeoR-
© The Author 2014. Published by Oxford University Press on behalf of ERA- ecormon® (epoetin beta) and Aranesp® (darbepoetin alfa).
EDTA. This is an Open Access article distributed under the terms of the Creative
Commons Attribution Non-Commercial License (http://creativecommons.org/
licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and
reproduction in any medium, provided the original work is properly cited. For 451
commercial re-use, please contact journals.permissions@oup.com
 Methods. PRIMS was a multicentre, multinational, non-inter- 54.3) versus 2.6/100 000 PY (95% CI 0.07–14.4; P < 0.0001) for
ventional, parallel-group, immunogenicity surveillance registry. coated-stopper syringe formulations [8]. In a study that re-
Adults with CKD receiving or about to initiate subcutaneous viewed US Food and Drug Administration reports of ESA-as-
Eprex®, NeoRecormon® or Aranesp® for anaemia were enrolled sociated PRCA between January 1988 and April 2004, PRCA
and followed for up to 3 years. Unexplained loss or lack of effect incidence was 18/100 000 PY for Eprex® with PS-80, 6/100 000
(LOE), including suspected PRCA, was reported, with antibody PY for Eprex® with human serum albumin, 1/100 000 PY for
testing for confirmation of PRCA. NeoRecormon® (epoetin beta), and 0.2/100 000 PY Epogen®
Results. Of the 15 333 patients enrolled, 5948 received Eprex® epoetin alfa with human serum albumin [7]. Following the
(8377 patient-years) and 9356 received NeoRecormon®/ introduction of Aranesp® (darbepoetin alfa) in 2001 some
Aranesp® (14 286 patient-years). No treatment data were avail- cases of PRCA have been reported in patients with CKD who
able for 29 patients. Among 23 patients with LOE, five cases of received this agent as their only ESA [10–12].
PRCA were confirmed (Eprex®, n = 3; NeoRecormon®, n = 1; The mechanism of Ab-mediated PRCA remains elusive [13].
Aranesp®, n = 1). Based on exposed time, PRCA incidence was It is proposed that compounds with adjuvant activity leached
35.8/100 000 patient-years (95% CI 7.4–104.7) for Eprex® by PS-80 from plastics and rubber materials in uncoated stop-
versus 14.0/100 000 patient-years (95% CI 1.7–50.6) for NeoR- pers [8, 14] induced an anti-EPO immune response [1, 6, 15].
ecormon®/Aranesp®. The incidence of PRCA with Eprex® was However, others have questioned whether adjuvants alone are
not significantly different versus comparator ESAs (rate ratio: sufficient for formation of self-reactive Abs [16]. Alternative po-
2.56; 95% CI 0.43–15.31). An analysis based on observed time tential explanations include protein denaturation and aggrega-
produced similar findings. tion from tungsten contaminants, or lower stability of the PS-80
Conclusion. This large, prospective registry demonstrates that formulation versus the previous formulation and thus increased
PRCA is rare with subcutaneous administration of either the susceptibility to, for example, cold-chain interruption [16, 17].
new coated-stopper syringe presentation of Eprex®, or NeoRe- Pending confirmatory evidence, SC administration of Eprex®
cormon® or Aranesp®. to patients with CKD was contraindicated in the European
Union (EU) in 2002 for interim risk mitigation. Following a
Keywords: chronic kidney disease, darbepoetin alfa, epoetin
worldwide withdrawal of Eprex® syringes with uncoated rubber
alfa, epoetin beta, pure red cell aplasia
ORIGINAL ARTICLE

stoppers in 2004, the Eprex® PS-80 formulation was reintro-

duced with coated-stopper presentations and in 2006 was ap-
proved in Europe for SC administration in patients with CKD
INTRODUCTION for whom intravenous (IV) access was not readily available.
Since that reintroduction and reinforcement of the cold-chain
Pure red cell aplasia (PRCA) is a rare haematological disorder [17], the incidence of reported ESA Ab-mediated PRCA asso-
characterized by severe and progressive normocytic, normo- ciated with SC administration of Eprex® in patients with CKD
chromic anaemia of sudden onset, reticulocytopenia and an has fallen dramatically worldwide (except in Thailand, where
almost complete absence of erythroid precursor cells in the local factors may explain a higher rate of PRCA reported with
bone marrow [1]. In patients receiving erythropoiesis-stimu- epoetin alfa [18–20]). In 2005, estimated PRCA rates reported
lating agents (ESAs), PRCA may occur secondary to the devel- with Eprex®, Epogen®, NeoRecormon® and Aranesp® were 0.2–
opment of neutralizing anti-erythropoietin antibodies (Abs) 0.3/100 000 PY, suggesting that PRCA is now rare with these
[2], which block the interaction of both ESAs and endogenous agents [4]. However, post-marketing adverse event reporting is
erythropoietin (EPO) with the EPO receptor [1]. often incomplete and PRCA rates among CKD patients receiv-
In the decade following the introduction of recombinant ing SC ESAs have not been prospectively quantified.
human EPO for treatment of renal anaemia in 1986, hundreds The EU post-approval commitment following reinstate-
of thousands of patients received ESA therapy [3] and only three ment of Eprex® for SC use included the Prospective Immuno-
cases of ESA-associated PRCA were published [4]. However, the genicity Surveillance Registry (PRIMS) as part of the Eprex®
number of cases of neutralizing EPO Ab-mediated severe Risk Management Plan. PRIMS was designed to estimate the
anaemia in CKD patients began to rise substantially in 1998 and incidence of EPO Ab-mediated PRCA among patients with
increased progressively to peak in 2001, before declining in 2003 CKD and provide assurance that the Eprex® coated-stopper
[5–7]. All cases during this period occurred in patients who re- PS-80 formulation has an acceptable immunogenicity profile
ceived subcutaneous (SC) administration of an ESA and almost when administered subcutaneously in this setting. Reference
all had received Eprex® epoetin alfa [5, 6]. This transient increase therapies included the two recombinant ESAs marketed at the
between 1998 and 2003 with Eprex® was associated with the use time of registry initiation: Aranesp® and NeoRecormon®.
of one product presentation—the polysorbate-80 (PS-80) formu-
lation in prefilled syringes with uncoated rubber stoppers (1000–
4000 and 10 000 IU strengths) [6, 8, 9]—which was introduced M AT E R I A L S A N D M E T H O D S
in 1998 to replace human serum albumin as a stabilizer and so
avoid the hypothetical risk of virus/prion transmission [1]. Study design and objectives
For 2001–2003 the rate of reporting of PRCA in patients This non-interventional immunogenicity surveillance regis-
exposed to SC PS-80 Eprex® in prefilled syringes and uncoated try employed a prospective cohort design with enrolment of
stoppers was 46.1/100 000 patient-years (PY; 95% CI 38.8– parallel groups across 751 sites in Europe and Australia

452 I.C. Macdougall et al.

F I G U R E 1 : Distribution of (a) the 751 sites from Europe and Australia that participated in the registry and (b) patients enrolled per country.

(Figure 1; www.clinicaltrials.gov identifier, NCT00391287; re- switching from SC to IV ESA administration, initiation of im-
gistered 20 October 2006). The registry was conducted in ac- munosuppressive therapy (e.g. following organ transplant-
cordance with the Declaration of Helsinki. Patients provided ation), or administration of any non-registry ESA. Patients in
written, informed consent if required by local regulations. the registry at the time of its termination were also considered
The primary objective was to estimate the incidence rate of completers. Patients were withdrawn due to loss to follow-up,
EPO Ab-mediated PRCA with SC administration of the coated- withdrawal of consent or death.
stopper syringe Eprex® PS-80 formulation and to compare this
with the incidence rate with other marketed ESAs (NeoRecor- Outcomes
mon® and Aranesp®). The secondary objective was to employ Data on ESA exposure, handling and storage; stage and

ORIGINAL ARTICLE
sensitivity analyses to examine the effect of varying the assumed treatment for CKD; and most recent Hb values were collected
latency of PRCA onset on incidence rates and incidence rate quarterly from patient notes. LOE was defined as loss or lack
ratios of EPO Ab-mediated PRCA. of therapeutic response, therapeutic response decrease, PRCA,
or EPO Ab-positivity. In such cases, the treating physician
Patients completed a PRCA-specific questionnaire, including medical
Eligible patients were those aged ≥18 years with documen- history, investigations for other causes of LOE/PRCA, and
ted CKD (stages 1–5, including stage 5D [21]) receiving SC results of relevant tests including iron stores, complete blood
Eprex®, NeoRecormon® or Aranesp® at enrolment or who were count, Hb, reticulocytes, and bone marrow examination (if
due to start such treatment within 1 month of enrolment, and performed). All usual causes of anaemia or LOE were excluded
considered likely to continue treatment for ≥1 year. Peritoneal before patients were deemed to have unexplained LOE. Unex-
dialysis, haemodialysis and non-dialysis patients were eligible. plained LOE, including suspected PRCA, was reported as a
Exclusion criteria included: >1 year since first SC exposure to serious adverse event (SAE).
any ESA; history of PRCA; prior loss or lack of effect (LOE) or EPO Ab testing was recommended for suspected PRCA.
unexplained, ongoing LOE with an ESA; and immunosuppres- Confirmation of EPO Ab-mediated PRCA required demonstra-
sive therapy (including transplant recipients). tion of EPO Abs by radio-immunoprecipitation, neutralization
Patients were enrolled through their CKD healthcare and/or other validated assays in a patient with unexplained
provider and observed for up to 3 years. Following registry ini- LOE. Potential (Ab-positive and Ab-borderline) cases of PRCA,
tiation, CKD healthcare providers were asked to review all including date of LOE onset, were adjudicated by a treatment-
non-enrolled patients seen subsequently for eligibility. blinded Independent Case Adjudication Committee.
Only ESA drug-related SAE reporting was mandatory.
Treatment Collection of other adverse events (AEs) and unrelated SAEs
All ESAs and concomitant medications were administered were left to investigator discretion or local health authority
as part of standard treatment and were expected to be consist- regulations.
ent with standard practice guidelines and local marketing
authorizations. The sponsor (Janssen, Pharmaceutical Com- Data analysis
panies of Johnson & Johnson) did not supply any ESAs or Throughout this report, ‘ESA exposure’ refers to SC exposure
other medications. unless otherwise stated. Incidence rates of LOE and PRCA were
calculated based on both exposed time (time during the registry
Completion and withdrawal in which the patient received a specific ESA) and observed time
Patient participation was completed in the following cir- (time at risk of development of PRCA assuming a latency of
cumstances: completion of 3 years of follow-up, completion of 1–12 months). Incidence rates of Ab-mediated PRCA were ad-
1 year of follow-up after SC ESA discontinuation, permanent justed for duration of ESA exposure, with CIs calculated using

Incidence of EPO antibody-mediated PRCA 453

 Table 1. Patient characteristics based on treatment at enrolment

Overall Eprex® Aranesp® NeoRecormon® Aranesp® plus No treatment data

(N = 15 333) (n = 5948) (n = 5974) (n = 3382) NeoRecormon® available at baseline
(n = 9356) (n = 29)
Median age, years 73.0 74.0 72.0 73.0 72.0 81.0
Male, n (%) 8669 (56.5) 3360 (56.5) 3395 (56.8) 1898 (56.1) 5293 (56.6) 16 (55.2)
Dialysis, n (%)
No 12 345 (80.5) 4903 (82.4) 4974 (83.3) 2439 (72.1) 7413 (79.2) 29 (100)
Yes 2988 (19.5) 1045 (17.6) 1000 (16.7) 943 (27.9) 1943 (20.8) N/A
Haemodialysis 2226 (74.5) 876 (83.8) 613 (61.3) 737 (78.2) 1350 (69.5) N/A
Peritoneal dialysis 762 (25.5) 169 (16.2) 387 (38.7) 206 (21.8) 593 (30.5) N/A
Cause of CKD, n (%)
Analgesic drug abuse 113 (0.7) 56 (0.9) 39 (0.7) 17 (0.5) 56 (0.6) 1 (3.4)
Diabetic nephropathy 4463 (29.1) 1750 (29.4) 1682 (28.2) 1025 (30.3) 2707 (28.9) 6 (20.7)
Glomerulonephritis 1620 (10.6) 517 (8.7) 714 (12.0) 388 (11.5) 1102 (11.8) 1 (3.4)
Multifactorial 28 (0.2) 10 (0.2) 7 (0.1) 11 (0.3) 18 (0.2) N/A
Polycystic/multicystic 731 (4.8) 274 (4.6) 294 (4.9) 162 (4.8) 456 (4.9) 1 (3.4)
kidney disease
Pyelonephritis/interstitial 1122 (7.3) 420 (7.1) 462 (7.7) 239 (7.1) 701 (7.5) 1 (3.4)
nephritis
Renovascular disease/ 5028 (32.8) 2081 (35.0) 1877 (31.4) 1058 (31.3) 2935 (31.4) 12 (41.4)
hypertension
Other 394 (2.6) 134 (2.3) 156 (2.6) 104 (3.1) 260 (2.8) N/A
Unknown 1834 (12.0) 706 (11.9) 743 (12.4) 378 (11.2) 1121 (12.0) 7 (24.1)

the Poisson distribution for rare events. Statistical significance

was assessed at the 5% level. A sample size of ≥20 000 PY of ex-
posure to Eprex® and ≥20 000 PY for comparators was planned.
ORIGINAL ARTICLE

Assuming a background rate of EPO Ab-mediated PRCA of 10/

100 000 PY for SC exposure to all ESAs, this would provide 0.50
power (α = 0.05, one-sided, two-sample Poisson) to detect a
4-fold greater incidence of EPO Ab-mediated PRCA with PS-80
Eprex® versus comparators.

R E S U LT S

Patient population
Between June 2006 and December 2010 15 333 patients
were enrolled (Figure 1), of whom 5948 received Eprex® and
9356 received Aranesp®/NeoRecormon®. Treatment data were
unavailable for 29 patients. As agreed with health authorities,
the registry was terminated early by concluding follow-up of
all ongoing patients on 31 December 2010, due to decreasing
recruitment, the impact of ESA switching, and the commercial
availability of ESA biosimilars.
The median age of the patients was 73 years and 56.5%
were male (Table 1). Most patients (80.5%) were non-dialysis
at enrolment. Of those on dialysis, 74.5% received haemodialy-
sis and 25.5% peritoneal dialysis (Figure 2). Except for differ-
ences related to dialysis, Eprex® and comparator subjects were
similar at enrolment. At the initial visit, 43.3% of patients re- F I G U R E 2 : K/DOQI CKD stage (a) and dialysis status (b) at enrol-
ceived the ESA by self-administration and 74.5% stored their ment. CKD, chronic kidney disease; K/DOQI, Kidney Disease Out-
ESA at home (Supplementary Table S1). comes Quality Initiative.

Erythropoietin-stimulating agent exposure in 12 months enrolment, 49.7% were SC-ESA naive and 45.4% had received
before enrolment Eprex® within the previous 12 months. Note that SC adminis-
Overall, 69% of patients had received prior ESA therapy tration of Eprex® in CKD patients remained contraindicated in
(Eprex®, n = 3317; Aranesp®, n = 4564; NeoRecormon®, n = the EU until a few months before registry initiation. Of the pa-
2698; Table 2). Among patients initiated on Eprex® at tients receiving Aranesp® and/or NeoRecormon® at enrolment,

454 I.C. Macdougall et al.

Table 2. ESA exposure in 12 months before enrolment

ESA exposure in 12 months before enrolmenta ESA at time of enrolment, n (%) Total, n (%)

Eprex® Aranesp® or NeoRecormon® Noneb

Eprex® 2319 (45.4) 12 (0.1) 14 (1.0) 2345 (15.3)
Other (Aranesp® and/or NeoRecormon®) 104 (2.0) 6545 (74.8) 45 (3.0) 6694 (43.7)
Both (Eprex® and ‘other’) 146 (2.9) 64 (0.7) 2 (0.1) 212 (1.4)
No ESA 2536 (49.7) 2130 (24.3) 1416 (95.9) 6082 (39.7)
Total 5105 (100) 8751 (100) 1477 (100) 15 333 (100)
a
Note that Eprex® SC administration in the treatment of CRF was still contraindicated a few months before the start of the registry.
b
Note that patients not receiving ESA treatment, but due to be initiated onto an approved ESA treatment within 1 month of enrolment were eligible for inclusion.

Table 3. Patient exposure, LOE and PRCA cases by product

ESA product Patients ESA- ESA treatment at last Cumulative ESA exposure Mean exposure Cases of LOE for Confirmed
naive at visit before from enrolment to per patient, which Ab testing was PRCA cases, n
enrolment, n (%) completion, n (%) completion/PRCA onset, months available, n (n = 11) (n = 5)
PY
Eprex® 2631 (44.2) 4242 (27.7) 8376.8 15.4 7 3
Aranesp® 1410 (23.6) N/A N/A 17.0 2 1
NeoRecormon® 682 (20.2) N/A N/A 15.7 2 1
Aranesp® and/or 2092 (22.4) 6240 (40.7) 14 286.3 17.3 4 2
NeoRecormon®
No ESA – 4851 (31.6)a 4614.2 – – –
a
Patients were observed for 12 months following permanent cessation of ESA treatment.

ORIGINAL ARTICLE
24.3% were SC-ESA naive and 74.8% had received Aranesp® Completion and discontinuation
and/or NeoRecormon® in the preceding 12 months. At enrol- Among all patients, 62.6% (9602 patients) completed the
ment, 9.6% of patients were receiving no ESA, of whom 95.9% registry. Reasons for discontinuation included death (n = 2627,
were SC-ESA naive. 17.1% of all patients), loss to follow-up (n = 2547, 16.6%), AEs
(n = 321, 2.1%), administrative reasons (n = 161, 1.1%), with-
drawn consent (n = 68, 0.4%) or medical reasons (n = 7,
Treatment switches
<0.1%). The proportion of patients lost to follow-up was similar
Of the 15 333 participants, 3086 switched to a non-registry for Eprex® (16.8%) and comparators (16.3%).
ESA, resulting in their early completion. Among patients who
switched, 37.6% had previously received Aranesp®, 34.5% Haemoglobin values over time
Eprex® and 27.9% NeoRecormon®.
At ESA initiation, mean Hb was lower among patients re-
ceiving Eprex® (10.9 g/dL) compared with patients receiving
Chronic kidney disease stage and dialysis status during NeoRecormon®/Aranesp® (11.3 g/dL). Mean Hb values were
the registry period similar between these treatments after 3 months (Eprex®, 11.7
At enrolment, patients were predominantly at CKD stage g/dL; comparator ESAs, 11.8 g/dL), and remained similar
4 (42.2%) or CKD stage 5 (34.1%), with very few at CKD stage throughout registry period (Eprex®, 11.6 g/dL; comparator
1 (0.1%), based on Kidney Disease Outcomes Quality Initiative ESAs, 11.5 g/dL at 36 months).
(K/DOQI) definitions (Figure 2) [21]. At 36 months, 25.4 and Mean Hb at ESA initiation was lower among ESA-naive
56.7% of patients were at CKD stages 4 and 5, respectively. patients (10.1 g/dL) than non-ESA-naive patients (11.2 g/dL),
The proportion of patients receiving dialysis increased from but was the same in both groups after 3 months (11.8 g/dL),
19.5% at enrolment to 47.3% at 36 months. and remained similar throughout the registry period (11.5 g/dL
at 36 months). There were no substantial variations in Hb by
treatment.
Cumulative erythropoietin-stimulating agent
and renin-angiotensin antagonist exposure Loss/lack of effect and antibody-mediated pure
Cumulative SC ESA exposure from enrolment to comple- red cell aplasia
tion/onset of PRCA was 8377 PY for Eprex® and 14 286 PY for Of the 28 LOE reports during the registry, 5 were subse-
the two comparator ESAs (Table 3). In calculating cumulative quently withdrawn, leaving 23 LOE cases (Figure 3). Anti-EPO
SC ESA exposure, missing data relating to exposure data, non- Ab testing was not performed at the time of LOE for 12 of
registry ESAs or non-SC administration were censored. Over these patients, most commonly because another cause of LOE
the registry period, 52.3–57.9% of patients regularly received was identified (n = 7; Table 4). Iron deficiency was reported as
renin-angiotensin antagonists. the cause of LOE for one of these cases. Although this could

Incidence of EPO antibody-mediated PRCA 455

ORIGINAL ARTICLE

F I G U R E 3 : Outcomes of investigations of LOE reports. Ab, antibody; ICAC, Independent Case Adjudication Committee; EPO, erythropoietin;
LOE, loss or lack of effect. aCause of LOE could not be confirmed by available laboratory data from the time of LOE for two cases with iron defi-
ciency (one Ab testing not performed, one Ab-negative) and the Ab-negative case with folate deficiency reported as the cause of LOE. bBone
marrow investigation was not suggestive of PRCA. cPRCA was excluded based on short duration of LOE (n = 3) or high reticulocyte count at
time of LOE (n = 1). dPatient tested negative for anti-EPO Abs ∼6 months after LOE onset. eScreening failure. fBone marrow suggestive of PRCA
in four cases; no bone marrow test for one case.

not be confirmed by laboratory data available from the time of deficiency. Since use of immunosuppressive therapy was an
LOE, bone marrow investigation was not suggestive of PRCA. exclusion criterion, the patient with methotrexate use repre-
In four of the 12 patients, the cause of LOE was not estab- sents a screening failure.
lished, but PRCA was excluded based on high reticulocyte The remaining five cases undergoing anti-EPO Ab testing at
count or short duration of LOE. A further patient developed the time of LOE tested Ab-positive and were adjudicated as
LOE after approximately 5 months of SC exposure to methoxy PRCA by the ICAC (Table 5; Supplementary data). Four cases
polyethylene glycol-epoetin beta (Mircera®), which was pre- of confirmed PRCA occurred after ESA initiation at enrolment
ceded by ∼2 years of NeoRecormon® treatment. Although the in previously ESA-naive patients (Eprex®, n = 3; NeoRecormon®,
cause of LOE was not identified and Ab testing was not per- n = 1). One case affected a patient with Aranesp® exposure prior
formed at the time, a sample taken ∼6 months after LOE onset to enrolment that continued throughout the registry. Four of
tested negative for anti-EPO Abs (Supplementary data). the five PRCA cases affected men, three occurred in France and
Evaluation for anti-EPO Abs was performed at the time of all five patients stored their ESA at home.
LOE for the remaining 11 cases, of whom 6 tested negative Based on exposed time, the rate of PRCA was 35.8/100 000
and had another cause of LOE identified: haemorrhage (n = 2); PY (95% CI 7.4–104.7) for Eprex® versus 14.0/100 000 PY
iron deficiency (n = 2); folate deficiency (n = 1); or methotrex- (95% CI 1.7–50.6) for Aranesp®/NeoRecormon® combined.
ate use (n = 1). However, laboratory data available from the The PRCA incidence rate ratio with Eprex® versus comparator
time of the LOE could not confirm the cause of LOE for one of ESAs was not statistically significant (2.56; 95% CI 0.43–
the patients with iron deficiency and the patient with folate 15.31). Based on observed time, the PRCA rate was 37.6/

456 I.C. Macdougall et al.

Table 4. Demographics, treatment, and bone marrow and anti-EPO Ab testing results in patients with LOE (n = 23)

Number Age at initial Race Country ESA(s)a Bone marrow EPO Ab status LOE cause
visit (years)/ findings
gender
1 80/Female White Germany Eprex® Not performed Negative Haemorrhage
2 75/Male White Sweden Aranesp® Suggestive of PRCA Positive Ab-mediated PRCA
3 58/Male White France NeoRecormon® Suggestive of PRCA Negative Methotrexate
4 77/Female White Italy Eprex® Suggestive of PRCA Negative Folate deficiencyb
5 62/Female White France NeoRecormon® Suggestive of PRCA Positive Ab-mediated PRCA
6 72/Male White Austria Aranesp®, Not performed Not performed Iron deficiency and haemorrhage
NeoRecormon®,
Eprex®
7 76/Male White Germany Eprex® Not performed Not performed Chemotherapy
8 75/Male White France Aranesp® Not performed Not performed Unknown; PRCA excluded based on
short duration of LOE
9 76/Female White France NeoRecormon® Not performed Not performed Inadequate ESA dose
10 76/Female White Italy Eprex® Not performed Negative Iron deficiencyb
11 57/Female White France Aranesp® Not performed Not performed Unknown; PRCA excluded based on
short duration of LOE
12 54/Female White Great Eprex® Not performed Not performed Unknown; PRCA excluded based on
Britain high reticulocyte count at the time of
LOE
13 73/Female White France Eprex® Not performed Not performed Unknown; PRCA excluded based on
short duration of LOE, which occurred
during hospitalization for sub-acute
pulmonary oedema
14 65/Male White Great NeoRecormon®, Not performed Not performed Myelodysplastic syndrome
Britain Aranesp®
15 84/Male White- Netherlands Eprex® Not performed Positive Ab-mediated PRCA very probable

ORIGINAL ARTICLE
Indonesian
16 91/Male White France Eprex® Suggestive of PRCA Positive Ab-mediated PRCA
17 82/Female White Great NeoRecormon® Not performed Not performed Sepsis
Britain
18 75/Female White Belgium NeoRecormon®, Not suggestive of Not performed Iron deficiencyb
Aranesp® PRCA
19 66/Male White Spain Eprex® Not performed Negative Haemorrhage
20 65/Male White France Eprex® Suggestive of PRCA Positive Ab-mediated PRCA
21 31/Male White Ireland NeoRecormon®, Not performed Not performed Unknown; a sample taken 6 months
Mircera® after LOE tested negative for anti-EPO
Abs
22 86/Female White France NeoRecormon®, Not performed Not performed Cancer
Eprex®
23 71/Male White France Aranesp® Not performed Negative Iron deficiency
a
All SC ESAs administered during the study are shown. SC ESA administered at the time of LOE is highlighted in bold, if known.
b
Cause of LOE could not be confirmed by available laboratory data from the time of LOE.

100 000 PY (95% CI 7.8–109.9) for Eprex® versus 13.9/100 000

PY (95% CI 1.7–50.3) for the pooled comparator ESAs, yield- DISCUSSION
ing a non-significant rate ratio of 2.70 (95% CI 0.45–16.15).
Varying the lag time between exposure and PRCA did not PRIMS is the first international registry to estimate the inci-
substantially change the rate ratios. dence of PRCA in ESA-treated patients with CKD, which had
not been quantified in a large prospective study since the 2006
EU reinstatement of SC Eprex® use in patients without readily
Safety available IV access. Few PRCA cases were detected during the
Drug-related SAEs were reported for 25 of the 15 333 partici- 4-year registry period, indicating that PRCA is a rare compli-
pants. The most commonly reported SAEs were blood and cation with the ESAs under evaluation.
lymphatic system disorders (n = 8, including PRCA, suspected Although the PRIMS PRCA incidence rates are not substan-
PRCA, unexpected anaemia and erythroblastopenia) and general tially lower than those based on post-marketing surveillance of
disorders and administration site conditions (n = 5). Review of the uncoated-stopper Eprex® presentation for 2001–2003 [8],
SAEs, including sensitivity analyses, revealed no new or unex- those estimates relied on spontaneous reporting and are widely
pected safety concerns. Of the 2936 deaths during registry believed to underestimate the true incidence. Since patients
conduct, one was assessed to have Eprex® as a possible contribu- were prospectively followed, with systematic LOE investigation
tory factor (bronchial cancer; not pathologically confirmed). and easy access to anti-EPO Ab testing, PRIMS should capture

Incidence of EPO antibody-mediated PRCA 457

 Table 5. Confirmed Ab-mediated PRCA cases (n = 5)

Case Age at Race Primary CKD CKD Product ESA Duration of Haematological PRCA treatment PRCA
onset of cause stage storage exposure features/ESA dose outcome
LOE up to LOE (before diagnosis of
(years)/ PRCA)
gender
1 76/Male White Renovascular 4 Aranesp® Home 14 months Unexplained LOE with Transfusions Unknown
disease and low reticulocyte count/
hypertension 20 µg QW increased to
20 μg twice per week
2 63/ White Renovascular 5 NeoRecormon® Home 6 months Unexplained LOE with Transfusions Not
Female disease and a Hb of 8.0 g/dL/4000 recovered
hypertension IU QW increased to
10 000 IU QW
3 92/Male White Unspecified 3 Eprex® Home 11 months Unexplained LOE with Corticosteroids, Recovered
a Hb of 6.1 g/dL/5000 transfusions
IU QW increased to
10 000 IU QW
4 66/Male White Unspecified 5 Eprex® Home 21 months Unexplained LOE with Transfusions Recovered
a Hb of 6.4 g/dL/5000
IU QW decreased to
5000 IU Q2Wa
5 85/Male White- Polycystic kidney 4 Eprex® Home 11 Months Unexplained LOE with Transfusions Not
Indonesian disease, a Hb of 6.3 g/dL/3000 recovered
renovascular IU QW increased to
disease and 8000 IU QW
hypertension
a
Onset of LOE occurred 5 months after reduction of ESA dose.
ORIGINAL ARTICLE

all PRCA cases occurring in the population. Moreover, the pro- [18]. Along with the continued occurrence of PRCA in clusters
spective cohort design allowed accurate recording of individual (e.g. in Singapore in 2013 [25]), these findings suggest the in-
patient ESA exposure over time. Therefore, PRIMS is expected volvement of an environmental factor in its pathogenesis [13].
to provide a more reliable estimate of PRCA incidence than The limited power of the registry was due partly to its early
spontaneous reporting. No significant difference in PRCA rates termination, the impact of treatment switches, the low inci-
was observed between Eprex® and comparators (rate ratio 2.7; dence of PRCA and the relatively small number of patients
95% CI 0.45–16.15). Although this could in part reflect the low meeting the entry criterion of ≤12 months of prior SC ESA
number of PRCA cases, which limited the registry’s power, exposure. Moreover, the registry was subject to the limitations
PRCA was sufficiently rare that it would take an immense study inherent in its non-interventional, non-randomized design,
to detect any potential difference in rates. which meant that between-group imbalances in baseline char-
The results of PRIMS cannot be generalized to estimate or acteristics could have affected the results. For example, a lower
compare the immunogenicity risk of non-registry ESA treat- proportion of patients in the Eprex® and NeoRecormon®
ments, including biosimilars. In a recent clinical trial of the groups versus the Aranesp® group were receiving peritoneal
epoetin alfa biosimilar HX575, two cases of EPO Ab-mediated dialysis, which may reflect the preferential prescription of a
PRCA were reported among the 337 participants [22]. long-acting ESA for these patients. Enrolment of non-ESA-
The low number of registry PRCA cases hinders evaluation naive patients into the registry could have introduced survivor
of potential associations with patient or treatment characteris- bias. However, SC administration of Eprex® had been newly re-
tics. The overrepresentation of males is consistent with previ- instated in the EU at the time of study initiation, leading to a
ous data, as is the possible clustering in France, which could greater proportion of ESA-naive patients in the Eprex® group
reflect the requirement for patients to collect ESAs from the (∼50%) than the comparator group (∼25%). Therefore, any
pharmacy and associated risk of breaking the cold chain [2, 6, such survivor bias would tend to favour the comparator group
7, 17, 22, 23]. All patients with PRCA received ESAs via SC due to its greater proportion of non-naive ‘survivor’ patients
administration, which is an established risk factor [13, 17]. and resulting underestimate of PRCA occurrence. Although
Along with the known increased risk of eliciting an immune we could not exclude PRCA for one patient with LOE, this
response with SC versus IV protein administration [24], SC patient did not receive Eprex®; hence, even if this case did re-
delivery also permits home ESA administration, which might present PRCA, it would not affect the estimated incidence rate
also increase the likelihood of cold-chain interruption and for Eprex®. We also note the relatively high rate of loss to
thereby facilitate the formation of immunogenic aggregates follow-up (16.6%), although this was comparable between
[13, 17]. All five registry patients with PRCA stored their ESA Eprex® and NeoRecormon®/Aranesp®.
at home. Protein aggregation has been associated with product Advances are being made in delineating the cause of EPO
mishandling during illegal trade of epoetin alfa in Thailand Ab-mediated PRCA in ESA-treated patients and cases continue

458 I.C. Macdougall et al.

to emerge across the product class [13]. This registry indicates Johnson & Johnson and Pfizer and has received an honorar-
that PRCA was a rare adverse event with SC administration of ium and travel expenses from Bayer. P.P. holds stock in
the new Eprex® presentation and its comparator treatments. Johnson & Johnson, the parent company of Janssen Cilag,
which markets Eprex®, and is an employee of Janssen, an oper-
ating company within Johnson & Johnson. A.P. is an employee
S U P P L E M E N TA R Y D ATA of Janssen. A.F. is an employee of Janssen. D.Fi. holds stock in
Johnson & Johnson and is a full-time employee of Janssen
Supplementary data are available online at http://ndt.oxford PRD. V.M. GTM from INC Research, mandated by Janssen. E.
journals.org. V. holds stock in and is an employee of Johnson & Johnson.

AC K N O W L E D G E M E N T S
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Nephrol Dial Transplant (2015) 30: 460–466

doi: 10.1093/ndt/gfu312
Advance Access publication 7 October 2014

Increased plasma dipeptidyl peptidase 4 activities predict

new-onset microalbuminuria in association with its
proinflammatory effects in Chinese without diabetes: a four-year
prospective study
ORIGINAL ARTICLE

Tianpeng Zheng1,2, Attit Baskota1, Yun Gao1, Haoming Tian1 and Fan Yang2
1
Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, Sichuan, P.R. China and 2Department
of Endocrinology and Metabolism, Affiliated Hospital of Guilin Medical University, Guangxi, P.R. China

Correspondence and offprint requests to: Haoming Tian; E-mail: dchaomingtian@126.com

In multiple linear regression analysis, baseline DPP4 activity

A B S T R AC T was an independent predictor of an increase in inflammatory
markers and ACR over a 4-year period (all P < 0.05). In multi-
Background. Recent evidence supports a protective role of di- variable-adjusted models, the odds ratio for incident MAU
peptidyl peptidase 4 (DPP4) inhibitors in lowering microalbu- comparing the highest with the lowest quartiles of DPP4 activ-
minuria (MAU) in diabetes but till now few studies have ity was 3.48 (95% CI: 1.50–8.09) after adjustment for con-
investigated the associations between DPP4 activity and MAU founding risk factors (P < 0.01). The incidence of MAU owing
in nondiabetic Chinese individuals. This study tested whether to DPP4 activity increased by 18.59%.
DPP4 activity could predict new-onset MAU in Chinese Conclusion. DPP4 activity is an important predictor of the
without diabetes. onset of inflammation and MAU in Chinese apparently
Methods. This was a 4-year prospective study conducted in without diabetes. This finding may have important implica-
Sichuan, China. A total of 664 Chinese women and men aged tions for understanding the proinflammatory role of DPP-4 in
18–70 years were studied. Circulating DPP4 activity, inflam- the pathogenesis of MAU.
matory markers and urinary albumin-to-creatinine ratio Trial Registration Number. #TR-CCH-Chi CTR-CCH-
(ACR) were measured at baseline and 4 years later. 00000361.
Results. The incidence of MAU during follow-up was 33.1 per
1000 patient-years. At baseline, individuals in the highest Keywords: ACR, DPP4 activity, inflammation, microalbumi-
quartile of DPP4 activity had higher age, body mass index, nuria
waist/hip ratio, systolic blood pressure, diastolic blood pres-
sure, fasting insulin, low-density lipoprotein–cholesterol,
INTRODUCTION
interleukin-6, high-sensitivity C-reactive protein, urinary
albumin-to-creatinine ratio and lower high-density lipopro- Microalbuminuria (MAU), a marker for early kidney damage, is
tein–cholesterol compared with individuals in the lowest quar- an established risk factor for chronic kidney diseases (CKDs),
tile. After a 4-year follow-up, 88 individuals developed MAU. cardiovascular disease (CVD) and cerebrovascular disease and

© The Author 2014. Published by Oxford University Press 460

on behalf of ERA-EDTA. All rights reserved.