AstraZeneca's $1B Bet on In Vivo CAR-T Therapy Shows Promise in Early Clinical Data

EsoBiotec's Groundbreaking Multiple Myeloma Treatment Demonstrates Efficacy

In a significant development for the field of cell therapy, EsoBiotec has released the first clinical data for its innovative in vivo CAR-T therapy, which recently attracted a $1 billion acquisition deal from pharmaceutical giant AstraZeneca. The preliminary results, published in The Lancet on July 2, 2025, showcase promising outcomes in patients with multiple myeloma, a challenging blood cancer that affects plasma cells in the bone marrow.

Clinical Trial Results: Efficacy and Safety Profile

The phase 1 trial, conducted in Wuhan, China, enrolled four patients with relapsed or refractory multiple myeloma who had previously undergone at least two other treatments. All four patients received a single infusion of EsoBiotec's lead asset, ESO-T01, which utilizes lentivirus vectors to deliver mRNA to T cells within the body. This novel approach aims to reprogram the patient's immune cells to target B-cell maturation antigen (BCMA), a protein often overexpressed in multiple myeloma cells.

The results were striking: all four patients responded to the treatment, with two achieving complete resolution of their cancer. Specifically, one patient's cancerous lesions and malignant blood cells in the bone marrow disappeared entirely by day 28 post-infusion, while another patient experienced complete remission two months after treatment. The remaining two patients showed partial responses, with noticeable shrinkage of lesions and reduction in cancer cells.

However, the treatment was not without side effects. All patients developed cytokine release syndrome (CRS), with three cases classified as grade 3 and one as grade 1. One patient also experienced grade 1 immune effector cell-associated neurotoxicity syndrome (ICANS). Other adverse events included acute inflammatory reactions, low blood pressure, blood toxicities, and lung infections.

Implications for the Pharmaceutical Industry

The promising results from EsoBiotec's trial represent a potential paradigm shift in the treatment of multiple myeloma and other blood cancers. The in vivo CAR-T approach could offer significant advantages over current ex vivo CAR-T therapies, which require complex and time-consuming cell extraction and modification processes.

AstraZeneca's substantial investment in EsoBiotec underscores the pharmaceutical industry's growing interest in innovative cell therapies. The $1 billion deal, announced earlier this year, includes an upfront payment of $425 million and up to $575 million in developmental and regulatory milestones. This strategic move positions AstraZeneca as a key player in the rapidly evolving field of in vivo CAR-T therapy.

While the initial data is encouraging, the authors of the study emphasize the need for larger cohorts and longer follow-up periods to fully assess the persistence and efficacy of the in vivo-produced CAR-T cells. As the trial progresses to enroll up to 24 patients, the pharmaceutical community will be closely watching for further developments that could potentially reshape the landscape of cancer treatment.