Sail Biomedicines, a Flagship Pioneering company, has entered a strategic collaboration with Johnson & Johnson (J&J) to develop in vivo CAR-T therapies for immune-mediated diseases. The partnership combines Sail's proprietary eRNA and targeted nanoparticle platform with J&J's development, manufacturing, and commercialisation infrastructure.

J&J will make initial payments totalling USD 785 million, comprising a USD 465 million equity investment and up to USD 140 million in development milestones, and holds an exclusive option to acquire Sail for an additional USD 2.58 billion.

Sail's platform integrates eRNA construct design, targeted nanoparticle engineering, and manufacturing as a coordinated system to direct therapeutic instructions to specific cell types with controlled expression duration. The vanguard programme targets autoimmune indications where durable disease remission through immune resetting is the goal.

The collaboration underscores growing industry conviction that in vivo CAR-T – by eliminating ex vivo manufacturing complexity – could transform chronic autoimmune management into scalable, potentially curative therapies, with Sail's AI-driven product engine providing a differentiated design capability.