Agenus colon combo shows no cancer in 72% of trial patients

Agenus Inc. said in an Oct. 25 Business Wire press release that 72% of 18 patients in a Phase 2 NEOASIS colon-cancer cohort had no cancer remaining at surgery.

Agenus said in the Oct. 25 press release that 83% had a major pathologic response after six weeks of treatment, compared with months of chemotherapy and up to a year of PD-L1 immunotherapy in the treatment path it described for these patients.

The results were presented at the European Society for Medical Oncology Congress 2026 in Madrid. NEOASIS is an investigator-initiated, single-center platform study sponsored by the Netherlands Cancer Institute, with Agenus supplying botensilimab, known as BOT, and balstilimab, known as BAL.

The cohort enrolled patients with mismatch repair-deficient, or dMMR, colon cancer, a tumor type marked by defects in DNA-repair biology. All 18 patients had non-metastatic, resectable disease.

“Nearly three out of four patients with locally advanced disease, had no cancer remaining at surgery after a single dose of botensilimab and two doses of balstilimab,” said Myriam Chalabi, principal investigator of the NEOASIS study at the Netherlands Cancer Institute.

The patients were high-risk by tumor stage. All tumors were at least T3, meaning they had grown into deeper layers of the bowel wall; 67% were T4 tumors and 72% had spread to nearby lymph nodes.

The regimen consisted of one 50 milligram dose of BOT on Day 1 and two 450 milligram doses of BAL on Days 1 and 22. Surgery was planned within eight weeks. Neoadjuvant treatment means therapy given before surgery.

Major pathologic response, the cohort’s primary endpoint, was defined as 10% or less viable tumor remaining at surgery. A pathologic complete response meant no cancer remaining in the tumor or nearby lymph nodes.

Nearly all patients, 17 of 18, had a pathologic response at surgery. At a median follow-up of 15 months, all patients were alive and 16 of 18 had no recurrence.

Immune-related side effects were mostly Grade 1 or Grade 2, the lower-severity categories used in clinical trials. One patient had Grade 3 colitis that resolved with treatment.

All 18 patients proceeded to surgery. Seventeen had surgery as planned, while one had earlier surgery on Day 41 because of a bowel obstruction and had a pathologic complete response.

The dMMR results do not address microsatellite-stable colon cancer, a larger segment of the market. Agenus said MSS disease accounts for about 85% of early-stage colon cancer cases and that it is advancing the short-course approach in that setting.

The main limit is scale. The release described early results from 18 patients at one center and did not report a randomized comparator, so the data do not establish how BOT and BAL would perform against standard care in a larger trial.

The regulatory position is also limited. BOT and BAL remain investigational outside Armenia and are not approved by the U.S. Food and Drug Administration, according to the release.

Netherlands Cancer Institute investigators are enrolling a dMMR rectal-cancer organ-preservation cohort within NEOASIS to evaluate whether BOT and BAL can allow selected patients to avoid surgery.

Source: Press release, Business Wire, Oct. 25, 2026.