Multiple myeloma is already served by therapies called T cell engagers, but toxicity remains a problem. GSK sees a way to overcome that limitation with a Chimagen Biosciences drug candidate it believes could become best in this class of targeted cancer drugs.
The deal announced Tuesday gives GSK global rights to the Chimagen drug, whose name and cancer targets remain undisclosed. Specific financial details are also confidential; GSK said only that its outlay could reach up to $750 million inclusive of an upfront fee and potential development and commercial milestone payments. GSK added that it expects the Chimagen drug will begin clinical testing in 2027. The asset faces potential competition from some of GSK’s big pharma peers.
T cell engagers, or TCEs, are antibodies that bind to both a T cell and a cancer cell, bringing them together so the immune cell can kill the malignant one. The FDA has approved four TCEs for multiple myeloma. Three of them — Johnson & Johnson’s Tecvayli, Elrexfio from Pfizer, and Regeneron Pharmaceutical’s Lynozyfic — bind to BCMA, a protein overexpressed on multiple myeloma cells. J&J’s Talvey binds to a different cancer target called GPRC5D. All four bispecific drugs carry black box warnings on their labels that cite the risks of an excessive immune response and neurotoxicity.
China-based Chimagen specializes in developing TCEs that bind to multiple cancer targets. GSK is acquiring a tri-specific TCE that Chimagen designed to bind to a T cell and two antigens found on cancer cells described only as validated tumor-associated antigens.
GSK said binding to both cancer targets could achieve a deeper and more durable response compared to currently available TCEs. The company added that this approach could improve tolerability. Those properties could support use of the drug in a broader range of multiple myeloma patients and as an earlier line of therapy in this malignancy, which is the third most common blood cancer globally behind lymphoma and leukemia.
“Today’s deal secures a promising T cell engager and advances GSK’s leadership goals in blood cancer,” Hesham Abdullah, GSK’s senior vice president, global head oncology, R&D, said in a prepared statement. “The agreement complements our existing portfolio in multiple myeloma, adding a new potential option to address the different needs of patients facing this complex disease.”
Other big pharma companies are already in the clinic with tri-specific TCEs. J&J is in early clinical development with ramantamig (formerly JNJ-79565322), a TCE designed to target BCMA, GPRC5D, and CD3. AbbVie is in Phase 1 testing with ABBV-2001 (formerly ISB 2001) a TCE acquired last year from IGI Therapeutics. This TCE targets BCMA, CD38, and CD3. The J&J and AbbVie trispecific TCEs are in development for multiple myeloma. Earlier this month, Roche agreed to pay $75 million up front for global rights to SIM0660, a trispecific TCE from Simcere Zaiming. The companies said this drug, designed to target CD79a, CD19, and CD3, has potential applications in a range of B cell-mediated diseases.
GSK’s commercial presence in multiple myeloma is through Blenrep, a BCMA-targeting antibody drug conjugate that received FDA approval last year as a third-line treatment. Additional clinical trials are evaluating the drug as an earlier line of multiple myeloma treatment. GSK already has experience with Chimagen TCEs. Two year ago, GSK acquired global rights to CMG1A46, a drug that was in early clinical development for leukemia and lymphoma. Under GSK, this TCE is in Phase 1 testing for both B-cell malignancies and B-cell-dependent autoimmune disorders. At the time of the deal, GSK highlighted lupus as a potential indication for the drug.
Photo: Eric Lalmand/ Belga Mag/ Belga/ AFP, via Getty Images
