Cambridge, Massachusetts-based Sail Biomedicines and Johnson & Johnson (NYSE: JNJ) announced a strategic collaboration to develop a portfolio of in vivo chimeric antigen receptor T-cell (CAR-T) therapies for immune-mediated diseases. The deal carries total potential value exceeding USD 3.5 billion and includes an exclusive option for J&J to acquire Sail outright.
Unlike conventional autologous CAR-T therapies, in vivo approaches aim to generate engineered T cells directly inside the patient's body, potentially eliminating individualized cell manufacturing. Sail's platform integrates three components: eRNA (Endless RNA), a circular RNA format engineered for enhanced stability and extended translational persistence compared to linear mRNA; targeted lipid nanoparticles designed to selectively transfect CD4+ and CD8+ T cells following systemic intravenous administration; and an AI-enabled design system for optimizing CAR constructs and delivery parameters. The lead program, SAIL-0804, encodes an anti-CD19 chimeric antigen receptor and is advancing toward investigational new drug (IND)-enabling studies. Preclinical data presented at the American Society of Gene & Cell Therapy (ASGCT) 2025 annual meeting demonstrated complete B cell ablation in humanized mouse models across blood, spleen, lymph nodes, and bone marrow, with 50–80% transfection of CD4+ and CD8+ T cells achieved across rodents, non-human primates, and human T cells in vitro.
Under the terms of the agreements, J&J will make total initial payments of USD 785 million to Sail, comprising a USD 465 million equity investment through Johnson & Johnson Innovation – JJDC Inc., its corporate venture capital arm, and USD 140 million in contingent payments tied to specified development milestones. The collaboration agreement itself is between Sail and J&J's subsidiary Janssen Biotech, Inc. The acquisition option, if exercised, would allow J&J to fully acquire Sail for an additional payment of USD 2.58 billion, with the combined transactions subject to applicable regulatory approvals.