Botensilimab + Balstilimab - (UNICORN)

Agenus (NASDAQ: AGEN) announced a peer-reviewed Nature Medicine publication of the investigator-sponsored multicenter Phase 2 UNICORN trial of neoadjuvant botensilimab (BOT) with or without balstilimab (BAL) in resectable, locally advanced colon cancer.

In pMMR/MSS disease, BOT+BAL met the trial’s primary endpoint: 36% major pathologic response (MPR), 29% pathologic complete response (pCR), and 71% overall pathologic response in 14 patients. BOT alone showed partial tumor regression in 43% but no MPR or pCR.

In dMMR/MSI-H disease, BOT+BAL produced 100% MPR and 93% pCR in 14 patients, versus 36% MPR and 29% pCR with BOT alone.

At the February 9, 2026 data cutoff, no patients treated with BOT+BAL had recurred; median follow-up was 19.2 months in pMMR/MSS and 16.7 months in dMMR/MSI-H, with 12-month event-free survival of 100% in both combination cohorts. Surgical timing was preserved in 98% of patients, all 56 underwent resection, and Grade 3/4 immune-related adverse events occurred in 2%.

The study also reported ctDNA clearance in all five evaluable pMMR/MSS patients who achieved MPR. Agenus said the UNICORN and NEST datasets support its planned global Phase 3 ROBBIN trial in high-risk Stage II/III MSS/pMMR colon cancer, with event-free survival as the primary endpoint.