Clinical outcome of patients who reduced sunitinib or pazopanib during first-line treatment for advanced kidney cancer.

Objectives To investigate the different outcomes in patients with metastatic renal cell carcinoma (mRCC) who receive a reduced first-line dose of sunitinib or pazopanib compared to those who continue at the standard dose. Patients and methods All the patients treated in 11 oncological centers in Italy for mRCC who started first-line treatment with sunitinib or pazopanib at the standard dose. Descriptive statistical tests were used to highlight differences among groups. Survival was estimated by the Kaplan-Meier method and compared across the groups using log-rank tests, the Cox proportional hazards model adjusted for statistically significant variables was also done. Results A total of 591 patients were included in the study. Of these, 45.7% received a reduced dose of sunitinib or pazopanib after a median treatment time of 3.6 months at the standard dose. The median overall survival in the patients who continued to receive the standard dose was 24.0 months compared to 49.4 months for those who received a reduced dose (hazard ratio = 1.80; 95% CI: 1.42–2.29; P<0.001). Only 45% of the patients received second-line therapy: 42.5% had an mTOR and 54.1% a tyrosine kinase inhibitor. Second-line overall survival was 19.8 and 11.8 months, respectively, in the patients who received, or did not, a reduced dose during first-line therapy (P = 0.007). Conclusions Toxicity-related dose reduction is a common event in mRCC patients who have started first-line therapy with either sunitinib or pazopanib. This is positively related to the outcomes of both first- and second-line therapy.