First-line sunitinib or pazopanib in metastatic renal cell carcinoma: The Canadian experience

INTRODUCTION: Clinical trial data has shown pazopanib to be non-inferior in overall survival (OS) compared to sunitinib as first-line treatment for metastatic renal cell carcinoma (mRCC). The purpose of this study was to evaluate outcomes and compare dose-modifying toxicities of mRCC patients treated with suntinib or pazopanib in the real-world setting. METHODS: Data were collected on mRCC patients using the prospective Canadian Kidney Cancer Information System (CKCis) database from January 2011 to November 2015. Statistical analyses were performed using Cox regression adjusted for several risk factors and the Kaplan-Meier method. RESULTS: We identified 670 patients treated with sunitinib (n=577) and pazopanib (n=93). There were no significant differences in International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) risk groups (p=0.807). Patients treated with sunitinib had improved OS compared with pazopanib (median 31.7 vs. 20.6 months, p=0.028; adjusted hazard ratio [aHR] 0.60; 95% confidence interval [CI] 0.38-0.94). Time to treatment failure (TTF) was numerically, but not statistically, improved with sunitinib (medians 11.0 vs. 8.4 months, p=0.130; aHR 0.87; 95% CI 0.59-1.28). Outcomes with individualized dosing on sunitinib were unavailable for this analysis. Patients treated with sunitinib had a higher incidence of mucositis, hand-foot syndrome, and gastroesophageal reflux disease; patients treated with pazopanib had a higher incidence of hepatotoxicity. CONCLUSIONS: In Canadian patients with mRCC, treatment with sunitinib appears to be associated with an improved OS compared to pazopanib in the first-line setting. Patient selection factors and the contemporary practice of individualized dosing with sunitinib may contribute to these real-world outcomes and warrant further investigation.