Costs of Adverse Events in Patients with Advanced or Metastatic Renal Cell Carcinoma with First-Line Treatment

This study evaluated costs associated with adverse events (AEs) in previously untreated real-world patients with advanced renal cell carcinoma (aRCC) in the USA. This retrospective longitudinal cohort study analyzed data from the Merative MarketScan Research Database (1 January 2014-30 September 2021). Adult patients with aRCC receiving first-line systemic treatments for aRCC (tyrosine kinase inhibitors [TKIs], or combination therapies of TKIs and immunotherapy) on or after the date of aRCC diagnosis were included. A total of 27 AEs of interest were included based on a review of product labels of the first-line treatments included in the study and identified using International Classification of Diseases, Ninth/Tenth Revision, Clinical Modification codes. Incremental costs associated with AEs between cases and controls (unadjusted and adjusted for relevant baseline characteristics) were estimated by two-part modeling. Analyses were performed over three AE cost assessment periods (7, 14, and 30 days). The study included 1681 patients with aRCC (mean [standard deviation; SD] age, 60.8 [10.6] years; 73.1% male), of which 1542 (91.7%) had at least one AE. AEs were mostly diagnosed in the outpatient (OP) setting. For most AEs, cases had significantly higher unadjusted and adjusted costs than controls. Costs associated with AEs ranged from < 300 US dollars (USD) for proteinuria to nearly 60,000 USD for hypophosphatemia. Seventeen AEs had adjusted 30-day costs exceeding 10,000 USD; of these, nine (pancreatitis, acute kidney injury, dyspnea, hypotension, hyperkalemia, hypomagnesemia, hyponatremia, hypophosphatemia, and neutrophil decreased/neutropenia) had 30-day costs exceeding 20,000 USD. The study was subject to limitations of all observational analyses of claims data (e.g., residual confounding). Observed cost differences may not have been solely attributable to an AE of interest. Study findings may not be generalizable to aRCC patient populations outside the USA. Most patients experienced at least one AE after initiation of first-line treatment with a TKI or combination therapies of TKIs and immunotherapy. There were substantial costs associated with AEs. Considering both safety and efficacy profiles when selecting optimal treatments can potentially mitigate healthcare costs for aRCC.