Continuous or intermittent? On the dosing schedule of sunitinib for advanced renal cell carcinoma

Sunitinib is globally approved for treatment of advanced renal cell carcinoma (RCC) at a dosage of 50 mg/day with four weeks on treatment and two weeks off, based on a randomized phase III trial in which its superiority over interferon alpha was established as first-line therapy for patients with metastatic RCC (1). On the other hand, continuous daily dosing of sunitinib at a dosage of 37.5 mg/day may be expected to provide consistent antitumor activity with a better safety profile compared with the 50 mg/day intermittent schedule according to two phase II trials (2,3). The recently published paper reported the result of a very interesting randomized phase II study called “Renal EFFECT Trial”, in which the efficacy and safety of sunitinib was directly compared between the 50 mg/day intermittent schedule and the continuous 37.5 mg/day as first-line therapy for patients with advanced RCC (4).