Suvemcitug Combination Shows Promise in MSS/pMMR Colorectal Cancer

A phase II study has analyzed the efficacy of suvemcitug, a new-generation recombinant humanized anti–vascular endothelial growth factor rabbit monoclonal antibody, combined with envafolimab and FOLFIRI chemotherapy, for the second-line treatment of microsatellite-stable or mismatch repair–proficient (MSS/pMMR) colorectal cancer (CRC).

The primary end points were recommended dose (RD) and objective response rate (ORR) by investigator assessment, and secondary end points were progression-free survival (PFS) and duration of response (DOR). Disease control rate (DCR), overall survival (OS), and safety were also analyzed.

Of 20 patients, 50% and 10% were previously treated with antiangiogenic agents and anti-EGFR agents, respectively. Patients were administered envafolimab, suvemcitug, and FOLFIRI until disease progression, unacceptable toxicity, or voluntary withdrawal occurred.

The ORR and DCR were 25.0% (95% CI, 8.7%-49.1%) and 90.0% (95% CI, 68.3%-98.8%), respectively, and DOR was 4.1 months (95% CI, 3.02-not reached [NE]). The median PFS and median OS rates were 5.6 months (95% CI, 4.0-8.3) and not reached (95% CI, 8.5- NE) by the time of study closure. The most common grade 3 or higher treatment-related adverse events included decreases in neutrophil and white blood cell counts and hypertension.

In the safety run-in stage, no dose-limiting toxicity events were seen at data cutoff. An RD of 2 mg/kg every 2 weeks was recommended for the treatment combination. The combination of suvemcitug, envafolimab, and FOLFIRI may serve as a new second-line treatment option for cold tumors in patients with MSS/pMMR CRC.