Second-line chemotherapy with weekly oxaliplatin and high-dose 5-fluorouracil with folinic acid in metastatic colorectal carcinoma: A Hellenic Cooperative Oncology Group (HeCOG) phase II feasibility study

Backround: Oxaliplatin is a novel platinum derivative, which, combined with 5-fluorouracil (5-FU), and folinic acid (FA), demonstrates synergistic activity in metastatic colorectal cancer (MCC). The HeCOG performed a multicenter phase II study of a weekly oxaliplatin administration schedule in patients with previously treated MCC to evaluate the antitumor efficacy and toxicity of this combination. Patients and methods: Eligible patients included those who relapsed after or during chemotherapy with 5-FU and FA and/or irinotecan. Prior radiotherapy was accepted provided that measurable disease was outside the radiation fields. Other eligibility criteria included written informed consent, a WHO performance status less than or equal to 2 and adequate bone marrow, liver and renal function. Treatment consisted of Oxaliplatin 50 mg/m(2) by two-hour intravenous (i.v.) infusion followed by FA 500 mg/m(2) (two-hour i.v. infusion) and 5-FU 2500 mg/m(2) (24-hour continuous i.v. infusion) on days 1, 8, 15, 22, 29, 36. The regimen was repeated every 50 days. Results: Thirty-two patients (Median age 61 years, range 25-76) entered the trial. The majority (75%) had progressed after receiving first-line chemotherapy. Diarrhea was the main non-hematologic toxicity. More than half of the patients (53%) developed grades 3 or 4 diarrhea. Due to this side effect only 29% of cycles were given with at least 90% of the planned dose of 5-FU. Hematologic toxicity included grade 3 neutropenia and thrombocytopenia (10% for each), and grade 4 thrombocytopenia (3%). Two patients (6%) died of sepsis, one related to neutropenia and one due to urinary tract sepsis. Sixteen patients (50%) developed grades 1 and 2 neurotoxicity in the form of sensory neuropathy, which was mild and transient. The objective response rate was 13% (95% CI: 3%-29%). All four responses were partial. Twelve patients (38%) had stable disease and 8 (25%) progressive disease. The median time to progression was three months and the median survival was nine months from the start of therapy. The Kaplan-Meier estimated probability of one-year survival for the group as a whole was 32%. Conclusions: The weekly administration of oxaliplatin with 5-FU and FA was associated with considerably less neurotoxicity than other schedules. However, the high percentage of diarrhea suggests that a dose reduction of 5-FU in this regimen may result in better therapeutic synergy.