GSK agreed to acquire global rights to a preclinical trispecific T-cell engager from Chimagen Biosciences in a deal valued at up to $750 million, with Chimagen eligible for success-based development and commercial milestone payments on top of an undisclosed upfront fee. The asset is expected to enter Phase I trials in 2027. The program is designed to engage T cells while simultaneously binding two validated tumor-associated antigens, with GSK planning development for multiple myeloma. GSK said the trispecific approach complements its existing multiple myeloma portfolio and could provide a new option in a disease where resistance eventually emerges. The transaction extends GSK’s China-focused innovation strategy and marks the second deal with Chimagen within less than two years, following a prior licensing agreement for a lupus prospect.