Single-center phase 2 trial of neoadjuvant envafolimab for mismatch repair-deficient, locally advanced colorectal cancer

Envafolimab is a subcutaneous PD-L1 inhibitor. A phase 2 trial at Sun Yat-Sen University (Guangzhou, China) evaluated neoadjuvant envafolimab for mismatch repair-deficient (dMMR), locally advanced colorectal cancer (CRC). Patients received subcutaneous envafolimab 300 mg every 3 weeks for three or four cycles. The primary endpoint was complete response rate. Among 13 patients who received at least one dose of envafolimab, seven (53.8%) achieved complete response (two clinical complete response, five pathological complete response). The median time to complete response was 3.1 months. Eleven patients underwent radical surgery, with no disease recurrence observed during follow-up. Treatment-related adverse events were mild and of low incidence (28.6%). With only one patient experiencing grade 3 fever. Subcutaneous administration was associated with high patient convenience and satisfaction. The authors conclude that this preliminary study suggests that envafolimab is a promising and safe neoadjuvant option for locally advanced dMMR CRC.