Temporal Trends in Grade 3/4 Adverse Events and Associated Costs of Nivolumab Plus Cabozantinib Versus Sunitinib for Previously Untreated Advanced Renal Cell Carcinoma

Background and Objectives: Novel immunotherapy-based combination treatments have drastically improved clinical outcomes for previously untreated patients with advanced/metastatic renal cell carcinoma (aRCC). This study aimed to assess the temporal trends in grade 3/4 adverse event (AE) rates and associated costs of nivolumab plus cabozantinib combination therapy versus sunitinib monotherapy in previously untreated patients with aRCC. Methods: Individual patient data from the CheckMate 9ER trial (nivolumab plus cabozantinib: N = 320; sunitinib: N = 320) were used to calculate the proportion of patients experiencing grade 3/4 AEs. AE unit costs were obtained from the United States (US) 2017 Healthcare Cost and Utilization Project (HCUP) and inflated to 2020 US dollars. Per-patient-per-month (PPPM) all-cause and treatment-related grade 3/4 AE costs over 18-months, temporal trends, and top drivers of AE costs were evaluated in both treatment arms. Results: Overall, the proportion of patients experiencing grade 3/4 AEs decreased over time, with the highest rates observed in the first 3 months for the nivolumab plus cabozantinib and sunitinib arms. Compared with sunitinib, nivolumab plus cabozantinib was associated with consistently lower average all-cause AE costs PPPM [month 3: $2021 vs. $3097 (p < 0.05); month 6: $1653 vs. $2418 (p < 0.05); month 12: $1450 vs. $1935 (p > 0.05); month 18: $1337 vs. $1755 (p > 0.05)]. Over 18 months, metabolism and nutrition disorders ($244), laboratory abnormalities ($182), and general disorders and administration site conditions ($122) were the costliest all-cause PPPM AE categories in the nivolumab plus cabozantinib arm, and laboratory abnormalities ($443), blood and lymphatic system disorders ($254), and metabolism and nutrition disorders ($177) were the costliest in the sunitinib arm. Trends of treatment-related AE costs were consistent with all-cause AE costs. Conclusions: Nivolumab plus cabozantinib was associated with lower costs of grade 3/4 AE management PPPM than sunitinib, which accumulated over the 18-month study period.