Real world (RW) use and outcomes of regorafenib (REG) flexible dosing in patients (pts) with metastatic colorectal cancer (mCRC) in Europe.

47 Background: In the phase 2 ReDOS study, REG first-cycle dose-escalation showed comparable activity and lower incidence of adverse events in pts with mCRC vs standard dosing. This retrospective cohort analysis aimed to examine RW dosing patterns of REG and associated duration of treatment (DoT) in pts with mCRC in Europe. Methods: Data from pts with mCRC, aged ≥18 years who initiated REG monotherapy from January 1, 2019 to April 30, 2022, were collected retrospectively from chart review by physicians recruited from the IQVIA OneKey database. Pts were categorized by dosing regimen to either flexible dosing regimens (ReDOS-like [<160 mg starting dose] or dose-adjusted [160 mg starting dose with dose adjustments during treatment]) or a standard dosing regimen (160 mg throughout treatment). Results: Overall, 355 pts (France, n=146; Italy, n=143; Belgium, n=66; 68% male, 54% aged ≥65 years) were eligible for inclusion. Nearly half (49%) received a ReDOS-like regimen, 32% received a standard dosing regimen, and 19% received a dose-adjusted regimen (Table). A higher proportion of pts on a dose-adjusted regimen had ≥3 metastatic sites (64% vs 43% for standard dosing) and most had initiated ≥3 REG cycles (93% vs 67% and 64% for ReDOS-like and standard dosing regimens, respectively). Pts receiving a ReDOS-like dosing regimen had worse performance status (ECOG PS ≥2, 35% vs 30% for dose-adjusted and standard dosing) and a higher proportion of KRAS (42% vs 37% and 30% for dose-adjusted and standard dosing regimens, respectively) or NRAS (28% vs 24% and 21% for dose-adjusted and standard dosing regimens, respectively) mutations. Median DoT was longer for ReDOS-like and dose-adjusted regimens vs standard dosing (1.4 and 1.9 vs 1.0 months, respectively; Table). Conclusions: Pts receiving REG flexible dosing regimens (ReDOS-like, dose-adjusted) had longer DoT compared with a standard dosing regimen despite having a higher frequency of adverse prognostic factors. Thus, this study affirms that flexible dosing strategies are viable options for optimizing REG treatment and outcomes in pts with mCRC. [Table: see text]