Merck & Co. signs $1.9B deal with Mestag to explore fibroblast therapies for inflammation

Mestag Therapeutics has been working to change how fibroblasts are activated and how they expand. Now, Merck & Co. wants in—penning a $1.9 billion biobucks deal to collaborate on new therapies for inflammatory diseases.

Details remain vague, with Mestag providing Merck with options to acquire licenses to develop and commercialize therapies against a “prespecified number of potential targets.” The exact upfront payment the British biotech will receive hasn’t been disclosed, either, but the company did say that combined with access fees, option fees and “downstream payments,” the total value of the deal could reach $1.9 billion.

Fibroblasts are a type of connective tissue cell that have long been studied in the areas of wound healing and fibrosis, or scarring, but were traditionally considered bit players when it came to tumors and inflammation. More recently, researchers have started to understand that fibroblasts play not just a supporting role but a central one in inflammation.

Cambridge, England-based Mestag launched in 2021 with a mission to develop single-cell algorithms that allow the company to see subtle differences between fibroblast cell populations, using its Reversing Activated Fibroblast Technology (RAFT) platform.

The company’s pipeline lists three preclinical programs, with the most advanced being MST-0300, a FAP-LTBR agonist designed to “supercharge” antitumor immunity. Behind it is M402, a stromal checkpoint agonist antibody meant to dampen myeloid-driven biology in inflammatory disease.

“Mestag was founded on groundbreaking insights into fibroblast-immune biology, and as an early innovator in this area of research, we have built a robust pipeline of antibody programs and created a unique and productive target discovery platform,” the biotech’s CEO Susan Hill, Ph.D., said in the Oct. 8 release.

Explaining the thinking behind the deal, Marc Levesque, M.D., Ph.D., vice president of immunology discovery at MSD Research Laboratories, said the role of activated fibroblasts in directing immune activity “offers exciting new therapeutic potential.”

“We look forward to collaborating with the team at Mestag to identify new potential therapeutic options for patients with fibrosis and inflammatory diseases,” Levesque added.

Merck isn’t the only drugmaker to have spied potential in Mestag’s fibrolast research, with Johnson & Johnson’s Janssen unit signing its own two-target collaboration agreement back in 2021.