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.