JFMC51-1702-C7: Phase II study investigating efficacy and safety of trifluridine/tipiracil (FTD/TPI) plus bevacizumab (BEV) in patients (pts) with metastatic colorectal cancer (mCRC) refractory or intolerant to standard chemotherapies

Abstract

Background: Combination treatment of FTD/TPI plus BEV in the C-TASK FORCE showed a promising activity in pts with mCRC refractory or intolerant to standard chemotherapies; however, due to the small sample size, it remains unclear if this combination works in the same way; RAS wild-type or mutant. We investigated the efficacy and safety of this combination in separate cohorts of RAS wild-type and mutant. Methods: mCRC pts refractory or intolerant to prior treatments with fluoropyrimidines, irinotecan, oxaliplatin, an angiogenesis inhibitor, and an anti-EGFR antibody if RAS wild-type, and without FTD/TPI and regorafenib. Pts received FTD/TPI (35 mg/ m2, twice daily, days 1 to 5 and 8 to 12) and BEV (5mg/kg, day1 and 15) every four weeks. The primary endpoint was disease control rate (DCR). A threshold and expected value of the DCR in each wild-type and mutant were set as 44% and 65%, respectively. Assuming a one-sided significance level of 5.0%, each target sample size was estimated to be 49 to achieve a power of 90%. Results: From Jan to Sep 2018, 102 pts were enrolled, and 98 pts fulfilled the eligibility (49 pts in each). Baseline characteristics of RAS wild-type vs. mutant were follows; median age, 65 vs. 64 years: male, 51% vs. 59%: ECOG PS 0, 69% vs. 59%: left-sided primary, 84% vs. 67%: number of metastasis of>2, 71% vs. 74%: median time from diagnosis of metastasis, 32.9 vs 21.2 months. The DCR in RAS wild-type was 65.3% (90% CI: 52.6-76.5%, p=0.0022), while that in RAS mutant was 55.1% (90% CI: 42.4-67.3%, p=0.0780). There was not a statistically significant difference in DCR between RAS wild-type and mutant after adjustment of baseline characteristics (adjusted odds ratio=0.48, 90% CI: 0.21-1.10, p=0.1435). Partial response was observed only in three pts with RAS wild-type. There were neither unexpected safety signals nor treatment related death. Conclusions: FTD/TPI plus BEV showed a promising activity with an acceptable safety profile for previously treated mCRC harboring either RAS wild-type or mutant. Survival outcome will be presented at the meeting.