FDA drug approval summaries: oxaliplatin

The purpose of this report is to summarize information on oxaliplatin, a drug recently approved by the U.S. Food and Drug Administration. Information provided includes regulatory history, study design, efficacy and safety results, and pertinent literature references. A single, multicenter, randomized trial, enrolling 463 patients with metastatic colorectal carcinoma whose disease had recurred or progressed during or within 6 months of completion of therapy with the combination of bolus 5-fluorouracil (FU)/leucovorin (LV) and irinotecan, was submitted. Study arms included infusional 5-FU/LV alone (arm A), oxaliplatin alone (arm B), and the combination of oxaliplatin and infusional 5-FU/LV(arm C). Oxaliplatin, at a dose of 85 mg/m2, was administered to patients in arms B and C intravenously over 2 hours in 250-500 ml of dextrose 5% in water (D5W) on day 1 only. A 200-mg/m2 dose of LV was administered simultaneously to arm C patients, in a separate bag using a Y-line, or alone to arm A patients, by i.v. infusion, over 2 hours. 5-FU was then administered to arms A and C patients, first as a bolus injection over 2-4 minutes at a dose of 400 mg/m2, then as a continuous infusion in 500 ml of D5W over 22 hours at a dose of 600 mg/m2. LV was repeated on day 2 of the cycle (arms A and C) followed by a 400-mg/m2 5-FU bolus and a 600-mg/m2 22-hour infusion. Treatment was repeated every 2 weeks. Response rate was the prespecified end point for accelerated approval. Time to progression (TTP) was a secondary end point. The prespecified primary comparison was between the 5-FU/LV regimen and the 5-FU/LV/ oxaliplatin combination regimen. The three arms were well balanced for patient prognostic factors. There were no complete responders. The partial response rates were 0%, 1%, and 9% for the 5-FU/LV, oxaliplatin, and oxaliplatin plus 5-FU/LV treatments, respectively (p = 0.0002, arm C versus arm A). The median times to radiographic tumor progression, based on available radiographs, were 2.7 months, 1.6 months, and 4.6 months, respectively (p < 0.0001, arm C versus arm A). Common adverse events associated with the combination treatment included peripheral neuropathy, fatigue, diarrhea, nausea, vomiting, stomatitis, and abdominal pain. Neutropenia was the major hematologic toxicity. Adverse events were similar in men and women and in patients <65 and > or =65 years of age, but older patients may have been more susceptible to dehydration, diarrhea, hypokalemia, and fatigue. Oxaliplatin in combination with infusional 5-FU/LV was approved for the treatment of patients with metastatic carcinoma of the colon or rectum whose disease has recurred or progressed during or within 6 months of completion of first-line therapy with the combination of bolus 5-FU/LV and irinotecan. Approval was based on response rate and on an interim analysis of TTP. No results are available, at this time, that demonstrate a clinical benefit, such as improvement in disease-related symptoms or survival.