Multicenter phase II study of bimonthly high-dose leucovorin, fluorouracil infusion, and oxaliplatin for metastatic colorectal cancer resistant to the same leucovorin and fluorouracil regimen.

PURPOSE: To evaluate the objective tumor response rates and toxicities of leucovorin (LV) plus fluorouracil (5-FU) cancer regimen combined with oxaliplatin (85 mg/m(2)) every 2 weeks on metastatic colorectal cancer patients with documented proof of progression while on bimonthly LV and 5-FU alone.

PATIENTS AND METHODS: One hundred patients were enrolled onto this study and 97 received the study drugs between October 1995 and December 1996. Eighty-nine patients were eligible for per-protocol efficacy analysis with documented proof of progression on one of the following two treatments: LV 500 mg/m(2) and continuous 5-FU infusion 1.5 to 2 g/m(2)/22 hours, days 1 through 2 every 2 weeks (FOLFUHD); or LV 200 mg/m(2), bolus 5-FU 400 mg/m(2), and continuous 5-FU infusion 600 mg/m(2)/22 hours, days 1 through 2 every 2 weeks (LV5FU2). In our study, 40 patients received FOLFUHD + 85 mg/m(2) of oxaliplatin day 1 (FOLFOX3) and 57 patients received LV5FU2 + 85 mg/m(2) of oxaliplatin day 1 (FOLFOX4).

RESULTS: Of the 97 patients treated, 20 partial responses were observed (FOLFOX3/4: response rate, 20.6%; 95% confidence interval, 13% to 31.1%; FOLFOX3: response rate,18.4%; FOLFOX4: response rate, 23.5%). For patients treated with FOLFOX3/4, the median response duration for was 7.5 months, and the major toxicities were peripheral neuropathy and neutropenia. The incidence of grade 3 (National Cancer Institute common toxicity criteria) peripheral neuropathy was 20.6%; whereas the overall incidence of grade 3 to 4 neutropenia was 27.8%, 15%, and 36.9% for FOLFOX3/4, FOLFOX3, and FOLFOX4, respectively (P =.02). From the start of treatment, median progression-free survival was 4. 7, 4.6, and 5.1 months for FOLFOX3/4, FOLFOX3, FOLFOX4, respectively, and median overall survival was 10.8, 10.6, and 11.1 months, respectively.

CONCLUSION: This phase II study of oxaliplatin at 85 mg/m(2) in combination with bimonthly LV plus 5-FU in patients with colorectal cancer resistant to LV plus 5-FU alone confirms the enhanced antitumor activity of oxaliplatin in combination with 5-FU.