Phase I Study Combining Treatment with Temsirolimus and Sunitinib Malate in Patients with Advanced Renal Cell Carcinoma

PurposeConcurrent inhibition of multiple oncogenic signaling pathways might improve the efficacy of anticancer agents and abrogate resistance mechanisms. This phase I study evaluated temsirolimus in combination with sunitinib in patients with advanced RCC.Patients and MethodsEligibility included advanced RCC and ≤ 2 previous systemic regimens. At the starting dose, temsirolimus 15 mg was administered by intravenous (I.V.) infusion once weekly, and sunitinib 25 mg was administered orally once daily for 4 weeks, followed by a 2-week rest period.ResultsIn the first cohort, dose-limiting toxicities (grade 3 treatment-related toxicities that lasted ≤ 7 days) were observed in 2 of 3 patients. One patient experienced grade 3 rash during week 3, which led to treatment discontinuation. A second patient had grade 3 thrombocytopenia (platelet count, 48,000/μL), cellulitis, and gout during week 3 and was hospitalized; platelets recovered to 109,000/μL 4 days after discontinuation of protocol therapy. A third patient experienced rash, asthenia, diarrhea, stomatitis, constipation, fever, and rectal hemorrhage, all of which were mild in severity. The study was terminated because of dose-limiting toxicity observed at low starting doses of both agents.ConclusionConcomitant use of I.V. temsirolimus 15 mg weekly and oral sunitinib 25 mg daily (4 weeks on, 2 weeks off) is not recommended.