AbbVie has completed its $2.1-billion acquisition of Capstan Therapeutics, a clinical-stage biotechnology company. The deal was announced in June 2025. 

Capstan’s lead asset, CPTX2309, is a targeted lipid nanoparticle (tLNP) that delivers an mRNA encoding an anti-CD19 chimeric antigen receptor (CAR) to CD8-expressing cytotoxic T cells in vivo. It is currently in Phase I development for the treatment of B cell-mediated autoimmune diseases. Additionally, AbbVie acquired Capstan’s proprietary tLNP platform technology designed to deliver RNA payloads, such as mRNA, capable of engineering specific cell types in vivo.  

In vivo CAR-T represents a potential new treatment modality in medicine embodying cell therapy with the accessibility and scalability of an off-the-shelf biologic. Mechanistically, B cells contribute to the pathogenesis of autoimmune diseases. CD19 is a cell surface receptor expressed on B cells and is a clinically validated target for B cell depletion using ex vivo CAR-T cell therapy in autoimmune diseases, according to information from AbbVie. CPTX2309, a product of Capstan’s proprietary technology platform that includes hepatic de-targeting, delivers an mRNA payload encoding an anti-CD19 CAR preferentially to reprogram CD8-expressing cytotoxic T cells. This process is achieved in vivo, without the need for lymphodepletion preconditioning and ex vivo manufacturing. The in vivo-modified CD8-expressing T cells will transiently express the CD19 CAR and deplete B cells in the periphery and tissues. Depletion of autoreactive antibody-producing pathogenic memory B cells and repopulation with naïve B cells, resulting in immune reset, has the potential to prevent disease progression and induce clinical remission, according to information from AbbVie.  

Source: AbbVie