Capstan Therapeutics launches with $165 million for cell engineering

Capstan Therapeutics has launched with $165 million for in vivo cell engineering to treat disease. The start-up’s technology is based on research from the University of Pennsylvania, with scientific founders including Tmunity Therapeutics’s cofounder Carl June and mRNA pioneer Drew Weissman.

Capstan says its initial focus is on chimeric antigen receptor (CAR) therapies, in which certain cells, usually T cells, are modified with receptors that allow them to attack and disable harmful antigens like cancer cells. This is often done outside the body: a person’s T cells are removed, modified to express the receptors, and reintroduced into the body. Capstan instead is developing in vivo CAR therapies, in which cells are engineered while they remain in the body.

The scientific founders have demonstrated a proof-of-concept for this in vivo platform in a mouse model of cardiac fibrosis. They packaged mRNA inside a lipid nanoparticle that was decorated with an antibody. The antibody targets the nanoparticle to T cells, says scientific cofounder Jonathan Epstein, who is the chief scientific officer at Penn’s Perelman School of Medicine. The T cells took up and expressed the mRNA, which encoded for a chimeric antigen receptor that led the T cells to a target involved in the condition (Science 2022, DOI: 10.1126/science.abm0594). Capstan’s platform, which could also be used for gene editing, could be applied to cancer, monogenic blood disorders, and autoimmune diseases, says CEO Laura Shawver.

Epstein notes that the platform uses many of the tools implemented in the mRNA COVID-19 vaccines, but the team started on the project before the pandemic. “It’s fun to think that we began our work before the rest of the world knew about mRNA and lipid nanoparticles to the extent that they know about them today,” he says.

Capstan’s funding includes $102 million from a series A round populated by pharma giants including Pfizer Ventures, Leaps by Bayer, Eli Lilly and Company, and Bristol Myers Squibb.