A phase II study of FOLFIRINOX with primary prophylactic pegfilgrastim for chemotherapy-naive Japanese patients with metastatic pancreatic cancer

Background Although FOLFIRINOX is currently one of the standard therapies for chemotherapy-naive patients with metastatic pancreatic cancer (MPC), the high rate of febrile neutropenia (FN) presents a clinical problem. This study aimed to evaluate the safety and efficacy of primary prophylactic pegfilgrastim with FOLFIRINOX in Japanese MPC patients. Methods FOLFIRINOX (intravenous oxaliplatin 85 mg/m(2), irinotecan 180 mg/m(2), levofolinate 200 mg/m(2), 5-fluorouracil (5-FU) bolus 400 mg/m(2) and 5-FU 46 h infusion 2400 mg/m(2)) and pegfilgrastim 3.6 mg on day 4 or 5, every 2 weeks was administered to previously untreated MPC patients. The primary endpoint was the incidence of FN during the first 3 cycles. The planned sample size was 35 patients, but the trial was predefined to discontinue enrollment for safety if 4 patients developed FN. Results At the enrollment of 22 patients, 4 patients developed FN in the first cycle, resulting in an incidence of FN of 18% {95% confidence interval [CI], 0.5-40.3%}, and enrollment was discontinued early. The incidence of grade 3 or higher neutropenia was 36.4%. Median relative dose intensities during the initial 3 cycles of oxaliplatin, irinotecan, bolus 5-FU, infusional 5-FU, and levofolinate maintained high (100%, 89.0%, 100%, 66.0%, and 100%, respectively). Response rate and median overall survival were 54.5% (95% CI 32.7-74.9) and 15.7 months (95% CI 7.9-18.8), respectively. Conclusions This phase II study could not demonstrate any reduction in the incidence of FN, nevertheless some patients experience benefits for efficacy by maintaining dose intensity using prophylactic pegfilgrastim.