Under the terms of this agreement, GSK will pay $300 million upfront to acquire full global rights to CMG1A46. In addition, Chimagen will be eligible to receive success-based development and commercial milestone payments for CMG1A46 totaling $550 million.

Tony Wood, chief scientific officer at GSK, said: “Through our work in systemic lupus erythematosus and lupus nephritis, we increasingly understand the underlying drivers of B cell-driven diseases. As a novel therapeutic option directed at deep B cell depletion, CMG1A46 offers exciting potential which we are pleased to take forward to address unmet need in lupus and related autoimmune conditions.”

CD20 is an established target in the treatment of autoimmune diseases and there is growing clinical evidence that CD19 shows promise as a differentiated therapeutic approach given its presence on more B cell types. In preclinical studies, CMG1A46 has shown rapid, deep B cell depletion both in the bloodstream and in tissues which could lead to more durable responses in patients, GSK said.

Zhenhao Zhou, Chimagen’s CEO, commented: “This agreement provides further validation of our proprietary T cell-engager platform, and we are eager to continue our mission of developing novel multi-specific antibody therapeutics.”

CMG1A46 is currently in phase I clinical trials in leukemia and lymphoma in both the US and China. GSK aims to begin a phase I trial in lupus in 2025.