August 1, 2025Open Access

Toripalimab, bevacizumab, and irinotecan in dMMR/MSI locally advanced colorectal cancer: First-stage results from a phase 1b/2 trial

Key Points

Pathological complete response rates reached 75% in the rectal cohort and 66.7% in the colon cohort, showing promising efficacy overall.
The study involved a phase 1b/2 trial with 14 patients in the colon cohort and 8 in the rectal cohort, indicating its limited scale.
Effectiveness of toripalimab combined with irinotecan and bevacizumab was evaluated, focusing on shared decision-making in treatment options.
No serious adverse events were reported, highlighting the manageable toxicity of this treatment regimen in these patient populations.

Abstract

This is the first stage of the phase 1b/2 trial evaluating the effectiveness and safety of toripalimab, irinotecan, and bevacizumab in patients with rectal cancer refusing up-front surgery or radiation therapy (rectum cohort) and patients with T4NanyM0 colon cancer (colon cohort) with deficiency of mismatch repair (dMMR) or microsatellite instability (MSI). This trial allows a doctor-patient shared decision-making process to determine whether to omit irinotecan or bevacizumab and the optimal surgery timing. The primary endpoint pathological complete response (pCR) rates in the full analysis set (FAS) and per-protocol set (PPS) are 57.1% (95% confidence interval CI 28.9-82.3) and 66.7% (34.9-90.1), respectively, in the colon cohort (n = 14) and 75.0% (35.6-95.5) and 100% (51.7-100.0), respectively, in the rectum cohort (n = 8). No disease recurrence occurs in PPS. No grade 4-5 drug-related adverse events are observed. Toripalimab with or without irinotecan and bevacizumab shows promising efficacy and manageable toxicity in dMMR/MSI T4NanyM0 colon cancer and locally advanced rectal cancer (ClinicalTrials.gov: NCT04988191).

Ask AI

Helpful

Bookmark

View Full Paper