Phase I Trial of Orally Administered Pentosan Polysulfate in Patients with Advanced Cancer1 in Vitroand
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Vol. 3, 2347-2354. Decel?lber /997 Clinical Cancer Research 2347 Phase I Trial of Orally Administered Pentosan Polysulfate in Patients with Advanced Cancer1 John L. Marshall,2 Anton Welistein, James Rae, dose was increased, but their seventies were similar at all Robert J. DeLap, Kim Phipps, John Hanfelt, dose levels. There were no objective responses, although three patients had prolonged stabilization of previously pro- Manasses K. Yunmbam, Jim X. Sun, gressing disease. Pharmacokinetic analysis suggested Kenneth L. Duchin, and Michael J. Hawkins marked accumulation of PPS upon chronic administration. Lombardi Cancer Research Center, Georgetown University Hospital. Serum and urine bFGF levels failed to show a consistent, Washington. DC 2X)7 Ii. L. M.. A. W.. J. R.. K. P.. J. H.. M. J. H.J: Baker Norton Pharmaceuticals. Inc.. Miami. Florida 33137 Ii. X. S.. interpretable pattern; however the data suggested an in- K. L. D.j: Division of Oncology Drug Products. Center ftr Drug verse relationship between PPS and bFGF levels in s’ivo. A Evaluation and Research. Food and Drug Administration. Rockville. MTD could not be determined using the daily t.i.d. dosing Maryland 20854 lR. J. Dl: and NIH. National Cancer Institute. schedule due to the development of grade 3/4 GI toxicity Bethesda. Maryland 20892 [M. K. Y.] (proctitis) at all dose levels studied. PPS, administered p.o. at doses of 400 mg/m2 t.i.d., did not cause significant sys- ABSTRACT temic toxicity, but most patients developed moderate-to- Tumor angiogenesis is critically important to tumor severe GI toxicity within 1-2 months. The cause of the GI growth and metastasis. We have shown that pentosan poly- toxicity was unclear, but it was readily reversible upon sulfate (PPS) is an effective inhibitor of heparin-binding cessation of the agent. The suggestion of an inverse relation- growth factors in vitroand can effectively inhibit the estab- ship between PPS and bFGF supports further study of PPS lishment and growth of tumors in nude mice. Following as an antiangiogenic agent. The tested doses and schedule completion of our Phase I trial of s.c. administered PPS, we cannot be recommended for further study. Subsequent mu- performed a Phase I trial of p.o. administered PPS in pa- rine experiments showed PPS to be more effective as an tients with advanced cancer to determine the maximum anticancer agent when it is given intermittently. We propose tolerated dose (MTD) and toxicity profile and to search for a study of PPS given on a weekly schedule in further clinical any evidence for biological activity in vivo. Patients diag- trials. nosed with advanced, incurable malignancies who met standard Phase I criteria and who did not have a history of INTRODUCTION bleeding complications were enrolled, in cohorts of three, to As reviewed by Folkman ( I ). it is becoming increasingly receive PPS p.o. t.i.d., at planned doses of 180, 270, 400, 600, evident that angiogenesis (new blood vessel formation is ot and 800 mg/rn2. Patients were monitored at least every 2 critical importance in the growth and metastatic spread of solid weeks with physical exams and weekly with hematological, tunors. Tumor growth in animal model systetils is limited in the chemistry, stool hemoccult, and coagulation blood studies, absence of vascularization, and inhibitors of angiogenesis that and serum and urine samples for PPS and basic fibroblastic are not cytotoxic or cytostatic in vitro can inhibit tumor growth growth factor (bFGF) levels were also taken. The PPS dose in l’il() (2-6). Furthermore. neovascularization may be a critical was escalated in an attempt to reach the MTD. Eight addi- determinant of the metastatic potential of a tumor. Tumor cells tional patients were enrolled at the highest dose to further may not gain entry into the systemic circulation in significant characterize the toxicity profile and biological in vivo effects numbers until tumor neovascularization has occurred, and of PPS. A total of 21 patients were enrolled in the three larger. more vascular tumors may shed more tumor cells into the cohorts of doses 180 (ii = 4), 270 (ii = 3), and 400 (ii = 14) bloodstream (7-9). Clinically. cancers often demonstrate a pre- mg/rn2. The most severe toxicities seen were grade 3 proctitis vascular or in situ phase and a more advanced vascular phase and grade 4 diarrhea; however, 20 of the 21 patients had (10-12). The appearance of’ angiogenic activity in a histologi- evidence of grade 1 or 2 gastrointestinal (GI) bleeding. These cally benign or i,i situ malignant lesion may be an important toxicities became evident at a much earlier time point as the indicator that neovascularization and transition to a more ma- lignant. invasive cancer will occur (13-17). Clinical studies have shown a positive relationship between the degree of tumor vascularization and metastatic spread (18, 19). Clinically. inter- Received 1/28/97: revised 9/1 1/97: accepted 9/29/97. ference with tumor angiogenesis could serve to delay or arrest The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked disease progression in cancer patients. Because active angiogen- advertise,ne,,t in accordance with 18 U.S.C. Section 1734 solely to esis in normal tissues of adults occurs only in certain physio- indicate this fact. logical situations (e.g. wound healing or the response of the I This work was supported by NIH Grant 5 VOl CA62500. uterine endornetriurn to hormonal stimulation). antiangiogenic 2 To whom requests for reprints should be addressed. at Lombardi therapy would be expected to have limited adverse effects on Cancer Research Center. Georgetown University Hospital. 3800 Reser- voir Road, NW.. Washington. DC 200()7. E-mail: marshalj@gunet. normal tissues. georgetown.edu. Angiogenesis is physiologically controlled by growth fac- Downloaded from clincancerres.aacrjournals.org on September 25, 2021. © 1997 American Association for Cancer Research. 2348 Phase I Trial of Oral PPS tors and growth factor modulators. HBGFs3 are particularly plasma and urine levels were higher than they were after the first potent in stimulating motility and proliferation of endothelial dose (Baker Norton Pharmaceuticals, Inc.). cells and inducing angiogenesis in several laboratory model We previously reported a Phase I study of PPS, adminis- systems (20-28). The HBGF family includes several known tered q.i.d. by s.c. injection, in patients with advanced cancer. members, which are now denoted HBGF-1-HBGF-7 (29, 30). Nineteen patients were enrolled in cohorts using escalating In addition to their effects in stimulating endothelial cells and doses from 60 to 120 mg/m2 q6h. The DLT was reversible angiogenesis, HBGFs have demonstrated mitogenic and differ- thrombocytopenia; also noted were prolonged activated partial entiation-inducing effects on several other types of normal cells thromboplastin time, hematuria, transient increases in transami- (31, 32). nases, bleeding from uterine fibroids, and rash. The recom- Studies have shown that malignant tumor cells commonly mended Phase II dose was 90 mg/m2 q6h. Although a few secrete substantial quantities of angiogenic growth factors, in- patients may have experienced stabilization of their previously cluding HBGFs. We have shown that PPS (also called pentosan) progressive malignancies, most of the patients with advanced is an effective inhibitor of HBGF-mediated cellular proliferation cancer enrolled in this study appeared not to benefit from PPS in vitro and can effectively inhibit establishment and growth of treatment (41 ). Plasma samples from patients were found to tumors in athymic mice that have been injected with tumori- have prolonged, high levels of circulating anti-HBGF activity, genic human cancer cells (33, 34). However, in other animal potentially sufficient to inhibit angiogenesis in microscopic tu- studies, PPS had little or no therapeutic effect on the progression mor deposits in vivo, with only modest effects on coagulation of established tumors. This is presumably because established parameters (42-44). tumors have already formed a blood supply and/or because On the basis of our experience to date, PPS may be most large, established tumors may elaborate very high levels of useful as an agent to suppress progression of cancer in patients growth factors, which cannot be effectively blocked by clini- who have a low tumor burden. For optimal results, chronic administration of PPS (possibly several times daily) for months cally tolerable doses of PPS. or years may be necessary. To date, most clinical pharmacolog- Because of its activity in retarding the blood coagulation ical studies of PPS have evaluated the s.c. route of injection. cascade (35), PPS is marketed outside the United States for use Although administration of PPS by repeated s.c. injection or by as a heparin-like anticoagulant in doses from 50 to 100 mg s.c. continuous infusion may be technically feasible, p.o. adminis- t.i.d., and it results in not only the expected toxicity of bleeding tration (if clinically safe and efficacious) would clearly be complications but also, rarely, thrombocytopenia, elevated preferable for long-term therapy. Published data suggest that transaminases, and thromboembolic reactions (36). Other din- p.o. administration of PPS may indeed be feasible, at least for ical trials have explored the role of PPS in the treatment of noncancer clinical indications. Here, we systematically evalu- chronic interstitial cystitis and chronic radiation-induced prod- ated the clinical, pharmacological, and in vivo biological effects titis (37). In prior studies of the treatment of interstitial cystitis, and the safety of escalating doses of p.o. PPS. PPS was supplied PPS has been administered p.o. at 100-300 mg t.i.d., for 3 to by Baker Norton Pharmaceuticals and was administered under > 18 months (38).