GSK Returns to Chimagen for Multiple Myeloma T-Cell Engager in Deal Worth Up to $750 Million
GSK is expanding its relationship with China’s Chimagen Biosciences, agreeing to acquire global rights to an experimental trispecific T-cell engager for multiple myeloma in a transaction worth up to $750 million.
The agreement, announced September 15, includes an undisclosed upfront payment and success-based development and commercial milestones. It remains subject to customary closing conditions. GSK plans to take the program into Phase I trials in 2027.
The candidate binds to T cells while simultaneously targeting two tumor-associated antigens. GSK hopes that design will deliver deeper, longer-lasting responses with better tolerability than existing T-cell engagers. The announcement did not disclose the molecule’s name or its two tumor targets.
That ambition addresses a central challenge in multiple myeloma drug development: improving cancer control while making treatment easier to tolerate. GSK describes the candidate as potentially best-in-class, but that remains a development goal; the announcement provides no human clinical results establishing superiority.
The acquisition follows GSK’s October 2024 agreement for CMG1A46, another T-cell engager developed by Chimagen. That transaction included $300 million upfront and up to $550 million in milestones, bringing its potential value to $850 million.
CMG1A46 targets CD19 and CD20 on B cells and engages T cells through CD3. When GSK announced the earlier acquisition, it emphasized development in B-cell-driven autoimmune diseases, particularly systemic lupus erythematosus and lupus nephritis. The rationale was to achieve deep B-cell depletion, including in tissues, potentially supporting more durable disease control.
According to GSK’s latest update, CMG1A46 is now in Phase I trials for B-cell malignancies and B-cell-dependent autoimmune disorders.
For Chimagen, the second agreement strengthens its relationship with a global drug developer and provides another commercial endorsement of its antibody-engineering platform. For GSK, it extends that relationship into a new program focused on multiple myeloma.
The next meaningful test will come in the clinic. Phase I development will begin to establish whether the new molecule’s design translates into a workable balance of safety, dosing and antitumor activity—the evidence needed to support its best-in-class ambition.
References
- GSK. GSK to acquire potential best-in-class T cell-engager for multiple myeloma from Chimagen Biosciences. September 15, 2026.
- GSK. GSK enters agreement to acquire CMG1A46 from Chimagen Biosciences to expand immunology pipeline. October 29, 2024.
