Phase I/II trial of temsirolimus combined with interferon alfa for advanced renal cell carcinoma

Temsirolimus, an inhibitor of the mammalian target of rapamycin, has single-agent activity against advanced renal cell carcinoma (RCC). A recommended dose and safety profile for the combination of temsirolimus and interferon alfa (IFN) were determined in patients with advanced RCC.

Patients were enrolled onto a multicenter, ascending-dose study of temsirolimus (5, 10, 15, 20, or 25 mg) administered intravenously once a week combined with IFN (6 or 9 million units [MU]) administered subcutaneously three times per week. An expanded cohort was treated at the recommended dose to obtain additional safety and efficacy information.

Seventy-one patients were entered to receive one of six dose levels. The recommended dose was temsirolimus 15 mg/IFN 6 MU based on dose-limiting toxicities of stomatitis, fatigue, and nausea/vomiting, which were observed at higher doses of temsirolimus and IFN. The most frequent grade 3 or 4 toxicities occurring in any cycle included leukopenia, hypophosphatemia, asthenia, anemia, and hypertriglyceridemia for all patients and those who received the recommended dose. Among patients who received the recommended dose (n = 39), 8% achieved partial response and 36% had stable disease for at least 24 weeks. Median progression-free survival for all patients in the study was 9.1 months.

The combination of temsirolimus and IFN has an acceptable safety profile and displays antitumor activity in patients with advanced RCC. Temsirolimus 15 mg plus IFN 6 MU is the recommended dose for evaluation in a randomized phase III study.