Evaluating Patient Adherence and Persistence to Tyrosine-Kinase Inhibitors for Metastatic Renal Cell Carcinoma: A Retrospective Analysis of Real-World Data.

Background: Combination therapy using an immune checkpoint inhibitor (ICI) and a tyrosine kinase inhibitor (TKI) is the standard first-line treatment for metastatic renal cell carcinoma (RCC). Oral TKIs enhance patient autonomy but require strict adherence and persistence. Methods: We analyzed adults with metastatic RCC at Chao Comprehensive Cancer Center, receiving at least 2 TKI prescriptions between April 29, 2019, and August 29, 2022, assessing adherence via Medication Possession Ratio (MPR) and Proportion of Days Covered (PDC). Results: A total of 66 individuals and 849 prescriptions were identified. The mean duration of TKI treatment was 237 days, with a median of 201 days. The mean persistence was 303 days, whereas the median was 233 days. Over 180 days, the median MPR was 83%, whereas the median PDC was 72%. The median variable PDC was 86%, while the median variable MPR was 105%. Asian patients experienced the longest average TKI therapy duration at 319 days, while Hispanic patients had the shortest at 223 days. Conclusions: We observed a significantly longer median duration of oral TKI therapy (201 days) than the reported national average (< 100 days). This analysis of real-world data reveals that lengthier treatment durations for TKI + ICI combinations are feasible.