Phase II study of carboxyamidotriazole in patients with advanced renal cell carcinoma refractory to immunotherapy: E4896, an Eastern Cooperative Oncology Group Study

BACKGROUND. The current study evaluated the response rate and 6-month time to disease progression of the antiangiogenesis agent carboxyamidotriazole (CAI) in patients with metastatic renal cell carcinoma (RCC). METHODS. Fifty-seven patients with histologically confirmed metastatic RCC that progressed after biologic therapy (interferon or interleukin-2) were enrolled. Four patients were ineligible. CAI was administered orally as a 28-day cycle. Response and time to disease progression were evaluated. RESULTS. Fifteen of 53 eligible patients received > 5 cycles, but 13 patients eventually discontinued treatment because of progressive disease. The majority of toxicities were Grade 1. However, Grade 3/4 toxicities did occur, the majority of which were gastrointestinal in nature. One of 47 patients evaluable achieved a partial response (1.9%) lasting 172 days. Six of 53 patients were alive and disease progression free at 6 months from the start of treatment (11.3%). The median overall survival was 12.5 months. The survival periods in the low-risk, intermediate-risk, and poor-risk groups were 16.2 months, 20.9 months, and 5.8 months, respectively. CONCLUSIONS. Patients in trials of second-line therapy appear to have a better prognosis than previously considered, in part because they are eligible for another clinical trial. CAI was found to have little to no effect on the natural history of progressive RCC.