Feasibility, Safety, and Efficacy of an Alternative Schedule of Sunitinib for the Treatment of Patients with Metastatic Renal Cell Carcinoma: A Retrospective Study

Background: Standard treatment with sunitinib for patients with metastatic renal cancer provides an ‘on-off’ schedule (daily administration of a 50-mg capsule for 4 weeks, followed by a 2-week break; consecutive 6-week cycles). We developed an alternative intermittent schedule to reduce the toxicity and symptoms of tumor regrowth during the rest period and to allow prolonged continuation of therapy, maintaining dose intensity. Objective: The objective of this study was to provide a retrospective evaluation of the feasibility, safety, and efficacy of an alternative schedule of sunitinib in patients who did not tolerate classical treatment. Methods: Patients treated with the classical schedule with at least grade 2 toxicity or recurrence of symptoms during the rest period were switched to an alternative schedule (the same daily dose 5 consecutive days per week for 5 weeks and then the same daily dose on days 1, 3, and 5 in the sixth week; consecutive 6-week cycles). Results: Twenty-five patients were enrolled. The median time from sunitinib initiation to schedule switch was 2.9 months. After the switch, the median therapy duration was 9.2 months. Rate of delay, corrected by cycle number, was 10% for both schedules. After the switch, 48.7% of patients obtained a toxicity reduction (hypertension −82%, stomatitis −71%, cutaneous toxicity −69%). A reduction in ‘on-off symptoms’ (−86%) was achieved. Overall response rate was 40% and the disease control rate was 80%. Median progression-free survival was 16.4 months and median overall survival was 41.3 months. Conclusions: Despite the small sample size and retrospective nature, we demonstrated the feasibility, safety, and efficacy of the alternative schedule, allowing prolonged treatment and better quality of life.