Comparing two tyrosine kinase inhibitors for treatment of advanced renal cell carcinoma in Medicare and commercially insured patients.

OBJECTIVE: The objective of this study was to compare treatment characteristics, survival and costs for sunitinib and pazopanib for advanced renal cell carcinoma (RCC) in a real-world setting.
METHODS: Using claims data, this observational, retrospective cohort study selected individuals aged 19 to 89 years, with commercial or Medicare insurance, advanced RCC, and at least one pharmacy claim for sunitinib or pazopanib between 1 November 2009 and 31 December 2012. Treatment characteristics (treatment interruption, adherence, duration and discontinuation), survival, and costs were measured up to 12 months. Statistical models were adjusted for age, gender, geographic region, race, and RxRisk-V score.
RESULTS: At baseline, pazopanib patients exhibited significantly worse health status indicators (RxRisk-V score, number of pharmacy claims, and pre-index total healthcare costs) than sunitinib patients. There were no differences in treatment characteristics or survival. Index medication costs (mean difference $5580, p = 0.03, adj p = 0.05) and total healthcare costs (mean difference $12,192, p = 0.09, adj p = 0.07) trended higher with sunitinib. Patients non-adherent with sunitinib incurred significantly higher total costs compared to patients non-adherent with pazopanib (mean difference $17,680, p = 0.04, adj p = 0.01).
CONCLUSIONS: Mortality data and proxy variables for treatment effectiveness indicate comparable clinical value for both medications. Sunitinib treatment trended towards higher index medication and total healthcare costs despite higher pre-index total costs and worse health status indicators at baseline with pazopanib. Non-adherence with sunitinib was associated with significantly higher total healthcare costs, which may indicate differences in tolerability between the two agents and requires further investigation.