Cartesian Therapeutics has signed a strategic licensing agreement with WestGene Biopharma to accelerate development of in vivo CAR-T therapies for autoimmune diseases, with a first clinical study expected to begin in the second half of 2026.

The collaboration combines Cartesian’s mRNA CAR-T payload technology, including the construct used in its lead candidate Descartes-08, with WestGene’s targeted lipid nanoparticle delivery platform. The companies aim to develop in vivo CAR-T therapies that could eliminate the need for complex ex vivo cell manufacturing.

The first programme under the agreement will evaluate the mRNA payload from Descartes-08 delivered using WestGene’s targeted lipid nanoparticles in patients with generalised myasthenia gravis.

A Phase 1 dose-escalation study is expected to begin in the second half of 2026, with initial clinical data anticipated during the first half of 2027.

Carsten Brunn, president and chief executive officer of Cartesian Therapeutics, said: “Building on our leadership in autologous cell therapy in autoimmune disease, we are partnering with WestGene to extend our mRNA payloads into in vivo delivery.

“We believe that the potential for in vivo to further enhance the delivery of cell therapies in the field of autoimmune disease provides a compelling commitment to scientific innovation.”

The study will assess intravenous administration of the therapy across multiple dose levels using a Bayesian Optimal Interval adaptive design and will include translational assessments alongside clinical response measures.

Cartesian said the programme represents a novel approach to BCMA-directed T-cell engineering that could simplify cell therapy manufacturing by generating CAR-T cells directly within the patient.

Beyond Descartes-08, the company plans to advance additional internally developed anti-BCMA CAR constructs and a BCMA-directed T-cell engager as part of its expanding mRNA payload portfolio.

WestGene has previously evaluated its targeted lipid nanoparticle platform in clinical studies across oncology and autoimmune diseases. According to the company, these studies demonstrated in vivo generation of CAR-T cells, sustained B-cell depletion and a favourable safety profile across multiple dosing regimens.

Xiangrong Song, co-founder and chief executive officer of WestGene, said: “WestGene brings the early clinical infrastructure to rapidly evaluate Cartesian’s constructs in vivo, and we believe this collaboration has the potential to meaningfully advance the treatment of autoimmune diseases.”

Under the terms of the agreement, WestGene will receive an upfront payment and may receive development and commercial milestone payments. Financial details were not disclosed.

Descartes-08 is currently being evaluated in a Phase 3 trial in generalised myasthenia gravis and in mid-stage studies across additional autoimmune indications.