Agenus (NASDAQ: AGEN) presented new clinical data for AGEN1181 as a monotherapy and in combination with balstiilimab at the 36th Annual Society of Immunotherapy of Cancer Meeting.
AGEN1181 monotherapy and balstilimab combination showing durable responses
Chief Medical Officer Steven O’Day commented, “AGEN1181 as monotherapy and in combination with balstilimab has shown durable responses in heavily pre-treated, poorly immunogenic ‘cold’ cancers, as well as those who have failed to respond to prior PD-1 inhibition. This regimen is well tolerated, with no hypophysitis, pneumonitis, or high-grade hepatitis observed to date. The clinical performance of AGEN1181 is consistent with its Fc-enhanced design, safely expanding the benefit of immunotherapy to a broader patient population.”
One hundred and sixteen patients were given AGEN1181 in a dosage escalation study to evaluate the appropriate monotherapy and combination dose with balstilimab as of September 17, 2021, the cut-off date. This population was substantially pre-treated, with roughly a third of patients having prior anti-PD-1 therapy and over half receiving at least three prior lines of therapy.
There were four cases of objective responses to AGEN1181 monotherapy confirmed. Partial responses (PR) in pancreatic cancer, complete responses (CR) in MSS endometrial cancer, and PD-1 refractory cervical cancer are among them. In these illness scenarios, they are the first reported responses to CTLA-4 monotherapy. Notably, the fourth response was in PD-1-refractory melanoma patients. Three of the monotherapy responders had a low-affinity FcRIIIA receptor, which has been linked to failure to respond to first-generation CTLA-4 inhibitors.
AGNE1181 promising in poorly immunogenic tumors
Phase I Program Director Anthony El-Khoueiry said, “AGEN1181 as monotherapy and in combination with balstilimab has shown promising activity in patients with poorly immunogenic tumors such as MSS-CRC, endometrial and ovarian cancers; these are tumor types that do not traditionally respond well to single agent anti PD-1/PD-L1 therapy. Importantly, multiple responders expressed the low affinity FcγRIIIA receptor, a feature that makes them less likely to respond to first-generation CTLA-4 antibodies. Together, this highlights the potential of AGEN1181 to fulfill unmet medical needs in the current treatment landscape by overcoming limitations of approved immunotherapies.”
