Not All Anti-CTLA4 Antibodies Are Alike

In several pivotal phase III trials, ipilimumab has been shown to improve overall survival among patients with metastatic melanoma. In this Phase III study of the cytotoxic T lymphocyte–associated antigen-4–blocking monoclonal antibody tremelimumab, 655 patients were randomly assigned to tremelimumab (15 mg/kg once every 90 days) or standard chemotherapy (dacarbazine or temozolomide).

The final study analysis was performed after 534 deaths had occurred. Median overall survival was 12.6 months (95% confidence interval, 10.8–14.3) with tremelimumab and 10.7 months (95% CI, 9.36–11.96) with chemotherapy (hazard ratio, 0.88; P=0.127). The objective response rates were 10.7% and 9.8% in the tremelimumab and chemotherapy groups, respectively, but …