To present the results of a Phase II trial of thalidomide and interferon-alpha in renal cell carcinoma.

Patients with metastatic clear cell renal cell carcinoma and no prior systemic therapy were accrued. Interferon-alpha was administered at 5 million units subcutaneously three times per week. Thalidomide was started at 100 mg/day for 2 weeks and then escalated 200 mg every 2 weeks to 1000 mg or until grade 3-4 toxicity developed. Patients were assessed radiographically at baseline and after 12 weeks. Steady-state thalidomide plasma concentrations were determined.

Thirty patients were enrolled. The median age was 62 years. Seventeen patients (57%) had undergone nephrectomy before therapy. One patient died during therapy. Of the 30 patients, 29 had at least grade 2 toxicity and 17 patients had at least grade 3. At 12 weeks, no patient had a complete response, 2 had a partial response (6.7%), 8 had stable disease (26.7%), and 11 (including 1 patient with an initial partial response) had disease progression (36.7%). Nine patients were removed from the study before 12 weeks. The median follow-up was 49.6 weeks (range 2.4 to 123.7). The median time of participation in the study was 11.1 weeks (range 1.4 to 63.9). At last follow-up, 2 patients were receiving the study therapy, 1 with stable disease at 64 weeks and 1 with a partial response at 53 weeks. The median survival was 68 weeks. A linear relationship was found between the thalidomide plasma concentration and dose. No relationship was apparent between the concentration and either treatment-related toxicity or response.

Interferon-alpha and thalidomide as front-line therapy for metastatic renal cell carcinoma showed limited activity. The objective response rate was 7%. One third of patients experienced toxicity that required discontinuation of thalidomide. Randomized controlled studies are needed to determine any objective benefit of this regimen over either drug alone.