Significance of introduction of alternative dosing schedule for sunitinib during first-line treatment of patients with metastatic renal cell carcinoma

The objective of this study was to investigate the significance of an alternative dosing schedule for sunitinib in metastatic renal cell carcinoma (mRCC) patients. This study included 154 patients treated with sunitinib as first-line systemic therapy for mRCC, consisting of 62, 47, and 45 receiving sunitinib based on a traditional schedule (TS, 4 weeks on and 2 weeks off) alone (TS group), alternative schedule (AS, 2 weeks on and 1 week off) alone (AS group), and TS followed by AS after the development of dose-limiting toxicities (TS-to-AS group), respectively. There were no significant differences in the major clinicopathological characteristics among these three groups. The progression-free survival in the TS group was significantly shorter than in the other two groups, while no significant differences in the overall survival were noted among the three groups. Adverse events (AEs) ≥ grade 3 in the TS and TS-to-AS groups occurred more frequently than in the AS group. Furthermore, there were significant differences in the incidences of AEs, including diarrhea, fatigue, and hypertension, among the three groups, favoring the AS compared with the other two groups. Despite the lack of a significant difference in the incidence of dose reduction among the three groups, the incidences of the interruption and discontinuation of sunitinib in the AS group were significantly lower than in the other two groups. These findings suggest that the introduction of AS for sunitinib during first-line treatment for mRCC patients may promote favorable clinical outcomes regarding the prognosis as well as tolerability compared with treatment on TS alone.