Phase II study of trifluridine/tipiracil (TAS-102) plus irinotecan in combination with bevacizumab as a second‐line therapy for patients with metastatic colorectal cancer.

155 Background: Metastatic colorectal cancer (mCRC) patients have poor prognoses with limited response to second-line chemotherapy. Therefore, it is urgent to refine and design an optimal second-line treatment regimen to improve the response rate and prolong the survival of patients with mCRC. This study assessed the safety and efficacy of the trifluridine/tipiracil (TAS-102), irinotecan, and bevacizumab regimen in second-line settings for mCRC patients. Methods: This was a multicenter, single-arm, phase II trial. The mCRC patients who are refractory to standard first-line treatment, including fluoropyrimidine and oxaliplatin, are eligible. Based on the recommended phase II dose established in phase I, enrolled patients received TAS-102 (30 mg/m2 twice daily on days 1-5) and irinotecan (150 mg/m2 on day 1) combined with bevacizumab (5 mg/kg on day 1) every two weeks. The primary endpoint was the objective response rate (ORR). Results: Between October 1, 2023, and August 31, 2024, 60 patients were enrolled, and all of them were evaluated for efficacy. As of August 31, 2024, efficacy was assessed in all 60 participants with an ORR of 18.3% (2 had complete response, CR; 9 had partial response, PR; 39 had stable disease, SD). Among the 39 patients with SD, 29 patients experienced tumor shrinkage. The disease control rate (DCR) was 83.3%. The median follow-up was 8.6 months (95% confidence interval [CI], 6.743-10.457). The six-month progression-free survival (PFS) was 59.6%. The median PFS was 6.9 months (95% CI 5.016-8.784), whereas the median overall survival (OS) was not reached. The 1-year OS rate was 92%. At the time of analysis, four patients have died, and 56 patients are still alive. All patients were evaluable for safety assessment. The most common treatment-related adverse events (TRAE) were nausea (100%), neutropenia (86.7%), and anemia (83.3%). The most frequent grade 3/4 TRAE were neutropenia (48.3%), febrile neutropenia (8.3%), nausea (3.3%), and anemia (3.3%). No treatment-related death occurred. Conclusions: The regimen of irinotecan, TAS-102, plus bevacizumab preliminarily demonstrated promising efficacy with tolerable toxicity for mCRC patients as second‐line treatment. This regimen warrants further exploration in refractory mCRC patients. Clinical trial information: NCT06202001 .