Real-World Economic Outcomes During Time on Treatment Among Patients Who Initiated Sunitinib or Pazopanib as First Targeted Therapy for Advanced Renal Cell Carcinoma: A Retrospective Analysis of Medicare Claims Data

BACKGROUND: The median age at renal cell carcinoma (RCC) diagnosis is 64 years. However, few studies have assessed the real-world time on treatment (TOT), health resource utilization (HRU), costs, or treatment compliance associated with targeted therapy use among patients in this age group with RCC. OBJECTIVE: To assess the HRU, costs, and compliance during TOT among Medicare patients aged ≥ 65 years with advanced RCC (aRCC) who initiated first targeted therapy with pazopanib or sunitinib. METHODS: Patients with aRCC were identified in the 100% Medicare + Part D databases administered by the Centers for Medicare & Medicaid Services. Eligible patients initiated first targeted therapy with sunitinib or pazopanib (index drug) on or after their first diagnosis of secondary neoplasm between October 19, 2009, and January 1, 2014, and were aged ≥ 65 years as of 1 year before first targeted therapy initiation (index date). Included patients were stratified into pazopanib and sunitinib cohorts based on first targeted therapy and matched 1:1 on baseline characteristics using propensity scores. TOT was defined as the time from the index date to treatment discontinuation (prescription gap > 90 days) or death. Compliance was defined as the ratio of drug supply days to TOT. Monthly all-cause costs and costs associated with RCC diagnosis (medical and pharmacy in 2015 U.S. dollars) and HRU (inpatient [admissions, readmissions, and days], outpatient, and emergency room visits) were assessed in the 1-year post-index period during TOT. Matched cohorts’ TOT was compared using Kaplan-Meier analyses and univariable Cox models, and compliance, HRU, and costs were compared using Wilcoxon signed-rank tests. RESULTS: Of 1,711 included patients, 526 initiated pazopanib and 1,185 initiated sunitinib. Before matching, more patients in the pazopanib cohort were white, diagnosed in 2010-2014 versus 2006-2009, and had lung metastases compared with the sunitinib cohort (all P < 0.05). The pazopanib cohort also had higher mean outpatient visits and costs but lower mean total all-cause pharmacy costs, than the sunitinib cohort (all P < 0.05). After matching, the pazopanib and sunitinib cohorts had similar characteristics (mean age 75 years, 58% male, and Charlson Comorbidity Index score of 9.2 in both cohorts) and median TOT (4.8 and 4.1 months, respectively). Among the 522 matched pairs, pazopanib was associated with significantly lower total all-cause health care costs ($8,527 vs. $10,924, respectively [mean difference = $2,397]); total medical costs ($3,991 vs. $5,881, respectively, [$1,890]); and inpatient costs ($2,040 vs. $3,731, respectively, [$1,692]; all P < 0.01) compared with sunitinib. Patients receiving pazopanib had significantly fewer inpatient admissions (0.179 vs. 0.289, respectively) and days (1.063 vs. 1.904, respectively; both P < 0.01) than patients receiving sunitinib. Mean treatment compliance was lower for the pazopanib versus sunitinib cohort (0.91 vs. 0.94, respectively; P < 0.01). CONCLUSIONS: In this retrospective analysis of Medicare patients with aRCC from a TOT perspective, first targeted therapy with pazopanib was associated with significantly lower all-cause health care costs and HRU, but lower compliance, compared with sunitinib.