Phase I/II study of PIXY321 in combination with cyclophosphamide and carboplatin in the treatment of ovarian cancer

OBJECTIVE: Our purpose was to evaluate the safety and biologic effects of PIXY321 after chemotherapy in patients with ovarian carcinoma. STUDY DESIGN: A multicenter, nonrandomized, phase I/II study of subcutaneously administered PIXY321 after the second cycle of chemotherapy in cohorts of three or more patients at 50, 125, 250, 500, 750, or 1000 μg/m² per day. RESULTS: Cyclophosphamide (600 mg/m²) and carboplatin (400 mg/m²) were administered every 28 days to 34 patients. At doses ≥500 mg/m² per day, the median nadir platelet and median nadir absolute neutrophil counts in cycle 2 (with PIXY321) compared with cycle 1 (control) were both higher in 13 of 26 (50%) patients. Twenty-one patients were withdrawn from the study. A total of 17 of 21 (81%) were removed for myelosuppression (n = 15) or PIXY321 toxicity (n = 2). A total of 28 of 34 (82%) patients had injection site reactions. Thirty- seven nonhematologic grade 3 events occurred. CONCLUSIONS: At these doses and schedules PIXY321 can be safely administered. Aggressive dosing of cyclophosphamide and carboplatin could not be maintained for six cycles in the majority (62%) of patients.