Real-world adherence in patients with metastatic colorectal cancer (mCRC) treated with trifluridine/tipiracil (FTD/TPI) or regorafenib (REG).

Abstract

11 Background: Adherence to oral chemotherapies is a critical but difficult to measure factor in the care of patients with advanced cancer. FTD/TPI and REG have both demonstrated prolonged survival in patients with refractory mCRC, but with notably different side effect profiles. This study utilizes real-world data to assess adherence and discontinuation of patients treated with FTD/TPI or REG and explore the effect of sequencing on adherence. Methods: Adults diagnosed with mCRC were identified using the nationally representative IQVIA Real-World Data Adjudicated Claims – US database (10/2014–07/2017). The first dispensing date of FTD/TPI or REG (if after FTD/TPI approval [10/2015]) was defined as the index date and the 3 months before as the baseline period. The observation period spanned from the index to the earliest date of a switch to another mCRC agent, end of continuous enrollment, or end of data availability. Medication possession ratio (MPR), proportion of days covered (PDC) at 3 months, and discontinuation (i.e., allowable gap≥45 days) were compared. Logistic (odds ratio [OR]) and Cox proportional hazards (hazard ratio [HR]) regressions, adjusting for baseline characteristics, were used to compare adherence and discontinuation, respectively. A subgroup analysis was conducted among switchers (FTD/TPI to REG vs REG to FTD/TPI). Results: A total of 469 FTD/TPI and 311 REG users were identified. FTD/TPI users had higher compliance with an MPR ≥ 80% (OR = 2.47; p < 0.001) and PDC ≥ 80% (OR = 2.77; p < 0.001). FTD/TPI users had lower risk of discontinuation (HR = 0.76; p = 0.006). Among switchers (96 FTD/TPI to REG; 83 REG to FTD/TPI), those switching from FTD/TPI to REG were more likely to have an MPR ≥ 80% (OR = 2.91; p < 0.001) and PDC ≥ 80% (OR = 4.60; p < 0.001) compared to REG to FTD/TPI switchers. Additionally, FTD/TPI to REG switchers had a lower risk of first treatment discontinuation (HR = 0.66; p = 0.009). Conclusions: In this study, FTD/TPI users had significantly higher compliance, lower discontinuation rate, and switchers treated first with FTD/TPI had better compliance, demonstrating that claims data can provide insight into oral chemotherapy adherence patterns in mCRC.