Background: Nearly all mRCC pts will be treated with one or more VEGFR TKI, alone or in combination with an immunotherapy (IO) or mTOR-inhibitor, during their therapeutic journey and may experience associated AEs. Evidence from the tivozanib (tivo) TIVO-3 trial suggests that median duration of clinically relevant VEGFR TKI class effect AEs is ≤90 days (range 14-90). Cost of AE management has not been clearly quantified to date. This study aimed to estimate how differences in TKI AE profile may impact treatment cost efficiency, particularly in later line (3L+) settings. Methods: iKnowMed EMR was used to identify mRCC pts from USON or Onmark Network, with matched 3^rd party insurance claims, that initiated VEGFR TKI treatment between Jan 2015 and Mar 2021. First occurrence of each VEGFR TKI class effect AE was indexed, and associated costs for 90-day (longest median AE duration) follow-up was captured. To assess burden across different TKIs, average per-patient AE management cost was calculated using incidence data from trials supporting FDA approvals, and weight-adjusted to estimated number of commercially insured 3L/4L pts in a 1,000,000-member plan. Results: 5,958 mRCC pts were identified, of which 4,464 were on at least one TKI regimen. Among those, 1,777 experienced an index AE; 1,072 successfully matched to claims data [median 69 years (range 25-94); 55% ECOG PS 0/1; 69% male], accounting for 1,667 unique index AE cases. Most were on cabozantinib (cabo), axitinib (axi), or pazopanib; lenvatinib (len), sunitinib (sun), and sorafenib were also represented. >80% were TKI only, with the rest TKI+IO (18%) or TKI+mTOR (6%). AE costs largely originated from outpatient visits (range 38-77%), excluding renal failure (58% inpatient). Mean cost per AE ranged from $76 (proteinuria) to $1,687 (mucositis/stomatitis). Overall, estimated costs of managing VEGFR TKI class effect AEs in 3L/4L showed lowest resource burden with tivo, and highest with len+everolimus (len+ev; Table). Conclusions: Average VEGFR TKI AE management costs derived from real-world mRCC pts demonstrated differences in healthcare resource burden, with overall anticipated cost dependent on TKI regimen utilized.

Note: Inc = Incidence (%), Cost ($).