Stylus Medicine is a biotechnology company based in Cambridge, Massachusetts, focused on developing in vivo genetic medicines. The company employs engineered recombinases and lipid nanoparticle (LNP) delivery systems to enable precise, non-viral genome integration of therapeutic payloads.

Stylus's platform aims to address limitations of ex vivo cell therapies by facilitating durable and scalable in vivo cell engineering. The initial therapeutic focus is on in vivo CAR-T therapies, with potential applications extending to oncology, autoimmune, and genetic diseases. 

In May 2025, Stylus emerged from stealth with $85 million in financing, comprising a $40 million Series A round and a $45 million Series A extension. Investors include RA Capital Management, Khosla Ventures, Chugai Venture Fund, Eli Lilly and Company, and Johnson & Johnson Innovation.

The leadership team is led by CEO Emile Nuwaysir, Ph.D., formerly of BlueRock Therapeutics and Ensoma, and CSO Jason Fontenot, Ph.D., previously of Sangamo Therapeutics and Juno Therapeutics. Stylus plans to utilize the funding to advance its platform and therapeutic programs toward clinical development.