A phase II trial of interferon-α and 5-fluorouracil in patients with advanced renal cell carcinoma: A Southwest Oncology Group study

BACKGROUND. Renal cell carcinoma is a common neoplasm that is often refractory to treatment. It is occasionally responsive to immunomodulating agents including interferon-α, which enhances the effects of 5-fluorouracil upon cells. Combinations of these two drugs have been most frequently tested in patients with gastrointestinal cancers, with some promising results. Because interferon-α has activity for renal cell carcinoma, a trial of this combination in patients with this malignancy was undertaken. METHODS. The Southwest Oncology Group performed a Phase II clinical trial of the combination of 5-fluorouracil and interferon-α for recurrent or metastatic renal cell carcinoma. Eligibility criteria included no prior treatment with medications for cancer, a performance status of 2 or better, and bidimensionally measurable disease. The regimen studied consisted of 5- fluorouracil, 750 mg/M²/day, by continuous intravenous infusion on Days 1- 5, and interferon-α-2b (Intron A), 5 x 10⁶U/M²/day, subcutaneously on Days 1, 3, and 5, repeated every 21 days. RESULTS. Forty eligible patients were treated; twenty of the 40 underwent a nephrectomy. The regimen was tolerable: 3 patients had Grade 4, and 17 had Grade 3 toxicity. There were 5 partial responses (13% with 95% confidence limits of 427%). Median progression free survival for all 40 patients was 4 months and median overall survival was 15 months from the time of registration. CONCLUSIONS. The combination of 5- fluorouracil and interferon-α given by this schedule, although tolerable and occasionally yielding responses, is not an improvement over existing therapies.