MXPA99007813A - Tamoxifen as a therapy to reduce irinotecan hydrochloride-induced diarrhea - Google Patents

Abstract

The present invention provides a method for preventing or decreasing diarrhea associated with irinotecan administration comprising the administration of tamoxifen at least two cell cycles prior to irinotecan administration.

Description

TAMOXIFEN AS A THERAPY TO REDUCE DIARRHEA INDUCED BY IRINOTECAN CHLORHYDRATE BACKGROUND OF THE INVENTION The present invention provides a new use of known pharmaceutical compounds. In particular, the present invention provides a method for reducing the side effects associated with the anti-cancer drug irinotecan by the prior co-administration of the anti-cancer drug ta oxifene. In humans, irinotecan hydrochloride, the active ingredient of CAMPTOSAR Injection, induces potentially life-threatening intestinal toxicity (diarrhea). The mechanism for this toxicity has been studied with the goal of identifying intervention therapy. Previous studies with hamsters have found that irinotecan blocks intestinal epithelial cells in the G2 phase of the cell cycle, concurrent with the onset of diarrhea. It is believed that this blocking of G2 reduces the differentiation of intestinal epithelial cells (a process associated with gi), resulting in a loss of REF .: 31006 physiological function and the onset of diarrhea. Based on the present findings, it is claimed that the blocking of normal epithelial cells in G0 / G? it could prevent entry to the S phase and thus protect these cells against toxicity by CPT-11 (N-38). Tamoxifen, a commercialized anti-estrogen chemotherapeutic agent, is known to induce a block in the Go / Gi phase of the cell cycle. As seen below, it is shown that tamoxifen: 1) improves the recovery of a non-tumor cell line from inhibition induced by SN-38, but increases the toxicity of SN-38 in a tumor cell line; 2) reduces weight loss attributable to diarrhea in hamsters treated with CPT-11; 3) reduces the colonic pathology and the physiological effects induced in the hamster by CPT-11. These findings indicate a potential therapeutic benefit in the co-administration of tamoxifen as a protective agent before and together with CPT-11.

DESCRIPTION OF INFORMATION Tamoxifen is a non-spheroidal antiestrogen with activity in the treatment (Jaiyesimi IA, Buzdar AU, Decker DA, Hortobagyi GN, Use of tamoxifen for breast cancer: twenty-eight years later J Clin Oncol 1995; 13: 513-529) and perhaps prevention (Gould K, Gates ML, Miaskowski C. breast cancer prevention: a summary of the chemoprevention test with tamoxifen, Oncol Nurs Forum 1994; 21: 835-840) of breast cancer. Contrary to most chemotherapeutic agents, which act in the S, G2 and M phases of the cell cycle, tamoxifen clearly blocks cell cycle progression in Go / Gi (Otto AM, Paddenber R, Schubert S, Mannherz HG.

Cell cycle arrest, micronucleus formation, and cell death in the development inhibition of MCF-7 breast cancer cells by tamoxifen and cisplatin, J Canc Res & Clin Oncol 1996; 122: 603-612). It is thought that this is through the repression of Gi-specific protein kinase activity (cyclin Dl / cdk4, Watts CKW, Brady A, Sarcevic B, Defazio A, Musgrove EA, Sutherland RL.) Anti-estrogen inhibition of progression of the cell cycle in breast cancer cells is associated with the inhibition of cyclin-dependent kinase activity and decreased phosphorylation of the retinoblastoma protein Mol Endocrin 1995; 9: 1804-1813). PCT Application WO96 / 01127, published January 18, 1996, describes a wide variety of agents to be coadministered with irinotecan, including tamoxifen. However, it does not describe the previous administration of tamoxifen.

BRIEF DESCRIPTION OF THE INVENTION The present invention particularly provides a method for preventing or reducing diarrhea associated with irinotecan therapy in a patient suffering from or susceptible to diarrhea, comprising administering to said patient an effective amount of tamoxifen at least two cell cycles before the administration of irinotecan. The preparation and use of irinotecan is known (see US Patent No. 4,604,463 which is expressly incorporated by reference herein). This is commercially available in the form of CAMPTOSAR Injection, sold by Pharmacia & amp;; Upjohn. The preparation and use of tamoxifen citrate is also well known (see US Patent No. 4,536,516, which is expressly incorporated by reference herein). This is commercially available as the active ingredient in NOLVADEX which is sold by Zeneca. The inhibitor of topoisomerase I, irinotecan hydrochloride; A camptothecin analogue has shown activity against a variety of tumor types, and in particular refractory colorectal tumors. The most limiting toxicity of the dose, in patients with cancer is a chronic, delayed, severe grade 3-4 diarrhea. Although somewhat manageable by existing means, therapeutic intervention to reduce or prevent chronic diarrhea in patients could allow more intense treatment strategies with irinotecan and increased comfort for the patient. Mechanistic studies in the hamster of Syria have shown that irinotecan produces considerable toxicity to the intestinal epithelium, which coincides with the onset of delayed diarrhea. This toxicity was characterized histologically by a loss of structural integrity, time-dependent, of the mucosal epithelium in the jejunum and ileum; the hairs appeared corrugated and the epithelial cells lost their typical colu mor morphology. The colon epithelium appeared thin and vacuolated. A reduction of the crypts and / or a loss of the epithelial cells was apparent. Using Western blotting techniques, a time-dependent rise in cell nuclear antigen (PCNA) proliferation was detected as early as on day 1. Immunohistochemistry for PCNA showed an increase in the number of marked epithelial cells and the intensity of the labeling in treated animals, with the positively labeled cells located farther towards the tip of the hairs compared to the controls. The increased levels of PCNA and the loss of differentiated cell morphology indicated that irinotecan induced a blockage of the cell cycle in S / G2 with a subsequent loss of physiological function (differentiated, Gi), in the hamster intestinal epithelium. This conclusion was further supported by studies indicating a reduction in crypt cell replication (detected by decreased labeling of brodesdeoxyuridine) and increased apoptosis (unpublished observations). The structural and biochemical changes in the intestinal epithelium coincided with the increased loss of water and electrolytes. In addition, studies in vi tro with SN-38, the active metabolite of irinotecan, have shown that HT-29 human adenocarcinoma cells stop at G2 / M, followed by apoptosis (Bacon JA, Y Maruyama, RF Kletzien, LA Foell i-Adams, and RG Ulrich Inhibition of the cell cycle and apoptosis by a topoisomerase inhibitor, irinotecan, J. Cell Biol., 1996 (Summary)). In contrast, normal WI-38 human fibroblasts were stopped in S / G2. Collectively, these studies indicate that irinotecan blocks cell replication in the S / G2 phase of the cell cycle, and that this blockage in the intestinal epithelial crypts leads to altered intestinal morphology and physiology. A variety of strategies for the control of diarrhea have been examined in humans and in animal models. In humans, co-therapies at high doses, aggressive, with lopera ida (an agent that delays intestinal motility and affects the movement of water and electrolytes through the intestine) has been used to reduce or control diarrhea (Rougier P, Bugat R. CPT-11 in the treatment of colorectal cancer, clinical efficacy and safety profile Semin Oncol 1996; 23 (Suppl 3): 34-41). Although it is useful in most cases, this agent requires administration at 2 hour intervals at the onset of diarrhea and is not used prophylactically. Chinese herbal medicine, ka po, has also shown that it controls diarrhea in rats and in humans. (See, for example, Takasuna K, Kasai Y, Kitano Y, Mori K, Kobayashi R, Hagiwara T, Kakihata K, Hirohashi M, Nomura M, Nagai E, and collaborators.) Protective effects of kampo and baicalin medicines against intestinal toxicity of a new anti-cancer camptothecin derivative, irinotecan hydrochloride (CPT-11), in rats Jpn J Cancer Res.; 86: 978-984; and Sakata Y, Suzuki H, Kamataki T. Preventive effect of TJ 14, a kampo medicine (Chinese herb), on diarrhea induced by irinotecan hydrochloride (CPT-11). Gan To Kagaku Rioho 1994; 21: 1241-1244). Although the mechanism is not clearly defined, it is thought that kampo's antidiarrheal activity is through the inhibition of beta-glucuronidase. This enzyme is responsible for the conjugation of the glucuronide form of the active irinotecan metabolite, SN-38. The deconjugation of the SN-38 glucuronide is thought to release the active SN-38 back into the intestinal lumen and produce toxic effects on the intestinal epithelium. Baicalin, a component of Kampo, has similar activity. Since most of the activity of intestinal beta-glucuronidase is due to the microbial flora, it has been suggested that antibiotics have protective effects (Takasuna K, Hagiwara T, Hirohashi M, Kato M, No ura M, Nagai E, Yokoi T, Kamatake T. Involvement of beta-glucuronidase in the intestinal microflora in the intestinal toxicity of the camptothecin derivative antitumor irinotecan hydrochloride (CPT-11) in rats Cancer Res 1996; 56: 3752-3757), again through the reduction of beta-glucuronidase activity. The effects of kampo medicines or other inhibitors of beta-clucuronidase on the pharmacokinetics of SN-38 or the efficacy of CPT-11 are not currently known. Other experimental co-therapies for the improvement of delayed diarrhea include the analogue of atostatin, octreotide (Cascinu S. Management of tumor-induced diarrhea or cancer therapy, Curr Opin Oncol 1995; 7: 325-329). In summary, the existing therapies are aimed at reducing the diarrhea induced by irinotecan through the reduction of intestinal motility or the prevention of deconjugation of the glucuronide SN-38. Surprisingly and unexpectedly, it has been found that treatment with an agent to block or slow the replication of epithelial cells in the G0 / G? of the cell cycle, before the start of DNA synthesis, could protect these cells against subsequent damage to DNA and apoptosis induced by CPT-11 in S / G2. In particular, tamoxifen has been found to have this protective effect. We claim that tamoxifen, by blocking intestinal epithelial cells in normal replication, in the G0 / G? of the cell cycle, will prevent or reduce intestinal toxicity due to the subsequent administration of CPT-11. This activity may require pretreatment of the patient for a period that encompasses approximately 2 cell cycles (or 48 hours), with continuous co-treatment at recommended oral dose levels of 20 to 40 mg / day (0.4-0.8 mg / kg / day). A similar protective therapeutic effect could be anticipated for other antiestrogens, including droloxifene, TAT-59, and raloxifene since these compounds have a pharmacological profile similar to tamoxifen (Jordan VC, Third Annual William L. McGuire Memorial Lecture. the estrogen receptor in breast cancer - 20 years as an objective for the treatment and prevention of cancer. "Breast Cancer Res Treat 1995; 36: 267-285). Studies with droloxifene, for example, show that this antiestrogen blocks cells in the Gi phase of the cell cycle, in a manner similar to tamoxifen (Hasmann M, Rattel B, Loser R, preclinical data for droloxifene, Cancer Lett 1994; 84 : 101-116).

DESCRIPTION OF THE PREFERRED MODALITIES The present invention is more fully observed in the following examples.

Detention of the Cell Cycle Induced by SN-38 and Apoptosis in Tumor Cells: Treatment of human colon adenocarcinoma HT-29 cells with SN-38, showed an inhibition of development > 90% (IC90) at a concentration of 10 nM. The flow cytometric analysis of the arrested cells in the development, revealed that the replication was blocked in the G2 phase of the cell cycle. From this point of detention, the cells did not recover but rather suffered programmed cell death (apoptosis) As HT-29 cells stopped, p53 levels were upregulated as determined by Western immunoblotting techniques, probably in response to detection of DNA damage, as PCNA levels were also increased. However, p53 expressed by HT-29 cells is a mutant (inactive) form since p21 is not upregulated; p21 could not be detected in these cells. These experiments show that CPT-11 (SN-38) induces apoptosis in HT-29 cells in a p53-independent manner from the G2 phase of the cell cycle.

Detention of the Cell Cycle Induced by SN-38, in Non-Tumor Cells: In contrast to the tumor cells, normal, human, WI-38 diploid lung fibroblasts treated with an IC90 of SN-38 (40 nM) were stopped in the S phase of the cell cycle as determined by flow cytometry. The cells did not suffer apoptosis, but rather slowly re-entered the cell cycle when the drug was withdrawn. The levels of p53 (wild type) were increased together with PNCA and followed by increases in p21.

Effects of Tamoxifen on Cell Replication in Cells Treated with SN-38: Normal WI-38 cells pretreated with tamoxifen before and during exposure to SN-38 recovered replication kinetics to a greater degree than those not pretreated. Tamoxifen increased the toxicity of SN-38 in tumor cells (Caco2). These data suggest that co-therapy with tamoxifen may increase the therapeutic ratio of CPT-11 by increasing the survival of normal proliferating cells, with a possible increase in the killing efficiency of tumor cells.

Toxicity of Irinotecan in the Hamster: The inhibition of cell replication and the induction of apoptosis in the hamster intestinal epithelium by CPT-11, which coincides with diarrhea and weight loss, has previously been demonstrated. When the hamsters were pre- and co-treated with tamoxifen, the weight loss associated with the administration of CPT-11 was reduced, and survival was increased. In another study, the pre- and co-treatment with tamoxifen showed that it produces an improvement in the morphology and function of the hamster colon in animals treated with CPT-11. These data indicate that tamoxifen produces in vi ve improvement.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (4)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. A method for preventing or reducing diarrhea associated with irinotecan therapy in a patient suffering from or susceptible to diarrhea, characterized in that the method comprises administering to said patient an effective amount of tamoxifen, at least two cell cycles before of the Irinotecan administration.

2. A method according to claim 1, characterized in that tamoxifen is administered approximately 48 hours before the administration of irinotecan.

3. The use of tamoxifen to prepare a medicament for preventing or reducing diarrhea associated with irinotecan therapy, in a patient suffering from or susceptible to said diarrhea, wherein tamoxifen is administered at least two cell cycles before irinotecan.

4. The use according to claim 3, characterized in that tamoxifen is administered approximately 48 hours before the administration of irinotecan.