Mestag Therapeutics

Mestag Therapeutics, founded in 2020, is a biotechnology company developing treatments for cancer and inflammatory diseases by focusing on fibroblast-immune interactions. The company was co-founded by CEO Susan Hill and a group of leading international researchers, including Professor David Tuveson of Cold Spring Harbor Laboratory, Professor Michael Brenner, Professor Chris Buckley, Professor Soumya Raychaudhuri, and Professor Mark Coles. Hill brings over 25 years of experience in the biotech and pharmaceutical industries, having held leadership roles at companies like Gyroscope Therapeutics, Orbit Biomedical, and Freeline Therapeutics.

Mestag's business model is centered on the discovery and development of a pipeline of first-in-class antibody programs. The company leverages its proprietary Reversing Activated Fibroblast Technology (RAFT) platform to identify novel drug targets by modeling the role of pathogenic fibroblasts in human diseases. Revenue is generated through strategic collaborations, licensing agreements, and milestone payments with major pharmaceutical companies. For example, Mestag has entered into collaborations with MSD (a trade name of Merck & Co., Inc.) and Johnson & Johnson. The agreement with MSD has the potential to total $1.9 billion through upfront payments, access fees, option fees, and downstream payments. The company has raised a total of $45 million in funding over three rounds, including a Seed round and a grant from Innovate UK. Key investors include SV Health Investors, Johnson & Johnson Innovation – JJDC, Inc., Forbion, GV (formerly Google Ventures), and Northpond Ventures.

The company’s product pipeline includes sophisticated antibody therapeutics. The M300 program is advancing a bispecific antibody, MST-0300, designed to induce the formation of tertiary lymphoid structures (TLSs) in solid tumors to drive anti-tumor immune responses, with an Investigational New Drug (IND) filing anticipated in early 2026. Another program, M402, is a first-in-class stromal agonist antibody that aims to reduce the over-activity of immune cells in inflammatory diseases like rheumatoid arthritis and lupus. By targeting fibroblast-driven immune signaling, Mestag aims to provide new therapeutic options for patients who do not respond to current treatments.

Keywords: fibroblast immunology, antibody therapeutics, inflammatory disease, immuno-oncology, drug discovery, bispecific antibodies, cancer research, stromal checkpoint, tertiary lymphoid structures, RAFT platform, autoimmune disease, targeted therapy, biotechnology, monoclonal antibodies, precision medicine, fibroblast biology, tumor microenvironment, immune regulation, first-in-class therapeutics, cell therapy