Benzinga | Feb 9, 2021 08:46AM EST

Agenus Reports 6 Total Confirmed Objective Clinical Responses In Colon, Ovarian, Endometrial Cancers, No Complement-Mediated Toxicities Reported

Agenus Inc. (NASDAQ:AGEN), an immuno-oncology company with an extensive pipeline of checkpoint antibodies, cell therapies, adjuvants, and vaccines designed to activate immune response to cancers and infections, today announced additional confirmed objective clinical responses from its Phase 1/2 trial of AGEN1181, its next-generation anti-CTLA-4, as monotherapy and in combination with Agenus' anti-PD-1 balstilimab.

"These are very exciting results which demonstrate the potential of AGEN1181 as an efficacious next-generation CTLA-4 antibody. AGEN1181 is showing activity in difficult-to-treat tumors without the neuroendocrine or significant liver toxicities commonly observed with the currently-approved CTLA-4 antibody ipilimumab," said Dr. Steven O'Day, Chief Medical Officer at Agenus. "The responses seen in patients with ovarian and MSS colorectal cancer are particularly encouraging given the generally low activity seen with immunotherapy in these indications."

The Phase 1 dose escalation trial has had no reports of complement-mediated toxicities. These are severe toxicities associated with first-generation CTLA-4 antibodies. The trial has also defined the optimal combination dose for AGEN1181 +/- balstilimab.

Agenus also presented on the first-ever report of intratumoral Treg depletion with a CTLA-4 antibody in clinical trials at SITC 2020.

The summary of responses with AGEN1181 alone or in combination with balstilimab are as follows:1

* CR in PD-L1(-) MSS endometrial cancer patient (1181 monotherapy)

* CR by PET in PD-L1(-) MSS endometrial cancer patient (1181 + bal)

* PR in PD-L1(-) refractory ovarian cancer patient (1181 + bal)

* PR in colorectal cancer patient (1181 + bal)

* PR in MSS colorectal cancer patient (1181 + bal) -- new confirmed response

* PR in ovarian cancer patient (1181 + bal) -- new confirmed response

AGEN1181 alone and in combination with balstilimab has expanded dosing into colorectal cancer. Phase 2 trials in additional cancer indications are scheduled to commence shortly.