Pfizer Reports Encouraging Safety Data For Novel Immunotherapy Combinations

(RTTNews) - Pfizer Inc. (PFE) announced results from Phase 1b trial of Pfizer's investigational immunotherapy agent utomilumab, a 4-1BB agonist, in combination with pembrolizumab, a PD-1 inhibitor, in patients with advanced solid tumors.

This is the first reported study of a 4-1BB agonist combined with a checkpoint inhibitor. Encouraging safety data from the study were shared today as an oral presentation at 52nd Annual Meeting of the American Society of Clinical Oncology (ASCO) in Chicago.

Of the 23 patients enrolled in the trial, six had a confirmed complete or partial response. The majority (four of six) of these responses lasted at least six months, with two patients maintaining their response for nearly one year at the time of data cut off. Treatment emergent adverse events were generally mild and did not appear to increase with higher doses of utomilumab, and no dose-limiting toxicity was reported.

"Pfizer believes that bringing the promise of immunotherapies for cancer to more patients will occur through combining agents that work on different pathways within the immune system," said Chris Boshoff, vice president and head of Early Development, Translational and Immuno-Oncology for Pfizer Oncology. "We are exploring numerous utomilumab combinations in order to better understand its potential role in mobilizing the immune system against difficult-to-treat cancers."

Pfizer said it is investigating utomilumab in both hematologic cancers and solid tumors in several planned and ongoing trials.