Checkmate Pharmaceuticals, Inc. announced the University of Iowa Holden Comprehensive Cancer Center's presentation of preliminary data from an investigator-sponsored phase 1/2 trial evaluating vidutolimod, a first-in-class, immunostimulatory, noninfectious virus-like particle (VLP) containing a CpG-A Toll-like receptor 9 (TLR9) agonist. The early phase trial is investigating intratumoral vidutolimod therapy in combination with intravenous pembrolizumab in patients with relapsed lymphoma. The objective of this study is to determine the dose of vidutolimod that, in combination with pembrolizumab, has optimal clinical efficacy and acceptable toxicity in patients with relapsed lymphoma who have failed at least one line of therapy.

In addition to the funding provided by Checkmate, the ongoing study is supported by NCI grant P50 CA97274 to the University of Iowa/Mayo Clinic (UI/MC) Lymphoma SPORE (specialized program of research excellence). During the 2022 ASCO Developmental Therapeutics—Immunotherapy Poster Session on Sunday, June 5 at 9:00am ET, Umar Farooq, M.D., Clinical Associate Professor of Internal Medicine at University of Iowa Hospitals & Clinics, principal investigator, and study sponsor, will present preliminary safety, response and translational laboratory data from 7 enrolled patients with relapsed lymphoma. Key highlights from the presentation include: Preliminary results suggest that in situ immunization with vidutolimod plus systemic pembrolizumab had clinical activity in a variety of lymphomas in 5 of 7 patients studied.

No significant adverse effects (AEs) were reported after the 4-hour observation period other than mild headache or fatigue lasting only through day 1. Consistent with preclinical data, generation of anti-Qß antibodies after the initial subcutaneous (SC) vidutolimod dose correlated with response to study treatment; further evaluation in additional patients is needed to confirm these initial observations. Additional evaluation of complex interactions between cells in the tumor microenvironment in response to vidutolimod will be needed to understand these findings. Study enrollment is ongoing and given the common use of B cell depleting therapies for the treatment of certain lymphomas, the study was modified to require generation of anti-Qß antibodies after the initial SC dose of vidutolimod before patients receive IT therapy.