A phase I pharmacological and biological study of PI-88 and docetaxel in patients with advanced malignancies.

PURPOSE: This study evaluated the safety, toxicity, pharmacological properties and biological activity of PI-88, a heparanase endoglycosidase enzyme inhibitor, with fixed weekly docetaxel in patients with advanced solid malignancies. EXPERIMENTAL DESIGN: This was a phase I study to determine the maximal-tolerated dose of escalating doses of PI-88 administered subcutaneously for 4 days per week, along with docetaxel 30 mg/m(2) given on days 1, 8, 15 of a 28-day schedule. RESULTS: Sixteen patients received a total of 42 courses of therapy. No dose-limiting toxicities were observed despite escalation to the highest planned dose level of PI-88 (250 mg/day). Frequent minor toxicities included fatigue (38%), dysgeusia (28.5%), thrombocytopenia (12%), diarrhea (14%), nausea (12%), and emesis (10%) in the 42 courses. No significant bleeding complications were observed. One patient developed a positive anti-heparin antibody test/serotonin releasing assay with positive anti-platelet factor 4/PI-88 antibodies and grade 1 thrombocytopenia in cycle 5, and was withdrawn from the study without any sequelae. PI-88 plasma concentrations (mirrored by APTT) and urinary elimination were linear and dose-proportional. Docetaxel did not alter the pharmacokinetic (PK) profile of PI-88, nor did PI-88 affect docetaxel PK. No significant relationship was determined between plasma or urine FGF-2, or plasma VEGF levels and PI-88 dose/response. Although no objective responses were observed; 9 of the 15 evaluable patients had stable disease for greater than two cycles of therapy. CONCLUSION: PI-88 administered at 250 mg/day for 4 days each week for 3 weeks with docetaxel 30 mg/m(2) on days 1, 8 and 15, every 28 days, was determined to be the recommended dose level for phase II evaluation. This combination was well tolerated without severe toxicities or PK interactions.

A phase II study of the heparanase inhibitor PI-88 in patients with advanced melanoma.

Treatment options for advanced melanoma are limited. PI-88, a potent inhibitor of heparanase, demonstrates anitangiogenic properties and has shown activity against melanoma in phase I studies. This was an open-label, multicenter, phase II study of PI-88 in patients with advanced melanoma. Patients received a fixed-dose of 250 mg/day given subcutaneously for four consecutive days followed by three drug-free days per week in a 28-day cycle. A total of 44 patients were enrolled in the intent to treat population, with 59.1% having received previous therapy. The median time to progression and overall survival was 1.7 months and 9 months, respectively. Forty-one patients are included in the efficacy analysis. One (2.4%) patient achieved a partial response, six (14.6%) patients had stable disease as best response, and 30 (73.2%) had progressive disease. At the end of six cycles of treatment, three of the 41 evaluable patients had non-progressive disease. Treatment was generally well tolerated. Injection site bruising occurred in 45% of patients. Serious bleeding did occur in two patients and three patients developed a positive anti-platelet antibody test during the study. One of these four patients experienced an associated thrombosis. In patients with advanced melanoma, PI-88 demonstrates an overall survival and time to progression similar to standard chemotherapy. Although the current study did not meet the primary end-point of progression free survival of >or=20%, there is some evidence of activity and further investigation is warranted.