Checkmate’s lead investigational drug is vidutolimod, which is believed to stimulate the immune system to fight tumors. An agonist of protein Toll-like receptor 9, vidutolimod is administered as a virus-like particle into tumors, where it is thought to induce and expand anti-tumor T cells. 

The therapy has demonstrated clinical responses in PD-1 refractory melanoma as a monotherapy. It is also undergoing Phase 1 trials in combination with other agents for treating melanoma and non-melanoma skin cancers, and head and neck cancer.

"As we continue to advance and expand our research efforts in immuno-oncology, the acquisition of Checkmate will add a promising new modality to Regeneron's toolkit of potential approaches for difficult-to-treat cancers," said Regeneron president and CEO Leonard Schleifer. "The unique combination of a differentiated Toll-like receptor 9 with other antibody-based oncology agents may result in increased clinical benefit and provide new treatment options for patients in need.”

Checkmate’s founder and chief scientific officer Art Krieg added: "We believe that the data we have generated with vidutolimod positions Checkmate at the forefront of the innate immune activator field. It is our hope that Regeneron's resources and expertise will help accelerate the development of vidutolimod and realization of the full potential of our virus-like particle (VLP) platform for immunotherapy.”

In March, Checkmate appointed Bristol Myers Squibb veteran Alan Bash as CEO. Bash had served more than 22 years at Bristol Myers Squibb, where he was latterly senior vice president, commercial model innovation.

Author: Elaine Burridge, Freelance Journalist