Biweekly TAS-102 and bevacizumab as third-line chemotherapy for advanced or recurrent colorectal cancer: a phase II, multicenter, clinical trial (TAS-CC4 study)

Background: TAS-102 improves overall survival (OS) of patients with refractory colorectal cancer (CRC), resulting in median progression-free survival (PFS) of 2.0 months (RECOURSE trial). Subsequently, a combination of TAS-102 and bevacizumab was shown to extend median PFS by 3.7 months. However, approximately half of these patients experience grade 3/4 neutropenia. In this study, we evaluated whether biweekly TAS-102 and bevacizumab therapy has efficacy equal to that of conventional TAS-102 and bevacizumab therapy and whether it reduces adverse hematological effects.

Methods: This phase II, investigator-initiated, open-label, single-arm, multicenter study was conducted in Japan. Eligible patients had previously received first- and second-line chemotherapy for metastatic CRC. TAS-102 (35 mg/m²) was given twice daily on days 1-5 and days 15-19 in a 4-week cycle, and bevacizumab (5 mg/kg) was administered by intravenous infusion for 30 min every 2 weeks. The primary end point was progression-free survival (PFS), and secondary end points were time-to-treatment failure (TTF), response rate (RR), OS, and safety.

Results: 44 patients with metastatic colorectal cancer were enrolled in this study. Median PFS was 4.6 months (95% confidence interval [95% CI] 3.6-5.3) and median OS was 10.5 months (95% CI 9.6-11.4). A partial response was observed in 2 patients (4.5%, 95% CI 0.4-16.0%). The most common adverse event above grade 3 was neutropenia (7 patients, 15.9%, 95% CI 7.6-29.7%).

Conclusions: Biweekly TAS-102 and bevacizumab therapy as third-line chemotherapy appears as effective as conventional TAS-102 and bevacizumab therapy, and this approach reduces adverse hematological effects.