Two consecutive phase II studies of oxaliplatin (L-OHP) for treatment of patients with advanced colorectal carcinoma who were resistant to previous treatment with fluoropyrimidines

Background Oxaliplatin (L-OHP) is a platinum complex that possesses activity against human and murine cells in vitro and in vivo, including colorectal carcinoma-derived cell lines, and cells that have been selected for resistance to cisplatin. We report two consecutive phase H trials of L-OHP for treatment of patients with advanced colorectal carcinoma. Patients and methods: Fifty-eight patients were entered in study I, and 51 patients in study II. All of the patients had tumor progression when they were treated, prior to their enrolment, with a fluoropyrimidine-containing regimen. In both trials treatment consisted of L-OHP, 130 mg/m2 by i.v. infusion for two hours; the treatment was repeated every 21 days. Results Response to therapy: Study I: Fifty-five patients were assessed for response. The response rate was 11% (95% CI, 0.03-0.19). Study II: All 51 patients were assessed for response. The response rate was 10% (95% CI, 0.017-0.18). The overall response rate for the 106 evaluated patients was 10% (95% CI, 0.046-0.16). Times to disease progression in responders were 4, 4, 4.5+, 5, 5, 6, 6, 6, 6+, 9, and 13 months. The dose-limiting toxic effect was sensory peripheral neuropathy. The incidence of severe peripheral neuropathy grades was: Study I: grade 3, 23% of patients, and grade 4, 8% of patients. Study II: grade 3, 14% of patients, and grade 4, 4% of patients. Severe neuropathy had a favorable course in all of the patients who had long-term neurologic follow-up. Diarrhea and myeloid impairment were minor. Conclusion L-OHP produced modest, but definite antitumor activity in patients with advanced colorectal carcinoma who were previously resistant to chemotherapy including fluoropyrirnidines. Toxicity is within acceptable limits of tolerance at the dose and schedule of oxaliplatin used in this tria