Biogen Inc. has entered into a definitive agreement with TJ Biopharma to acquire exclusive rights to the investigational drug felzartamab in the Greater China region, completing its global ownership of the asset. The deal strengthens Biogen’s position in immunology and expands its footprint in one of the world’s largest pharmaceutical markets.
Under the terms of the agreement, TJ Biopharma will receive an upfront payment of $100 million and could earn up to $750 million in additional milestone payments tied to commercial and sales performance. This brings the total potential value of the deal to $850 million, along with tiered royalties on future net sales in the Greater China region. Biogen expects to record the upfront payment as an acquired in-process research and development expense in the second quarter of 2026.
Felzartamab is currently being evaluated in multiple global Phase 3 clinical trials targeting immune-mediated diseases. With this acquisition, Biogen assumes full worldwide rights to the therapy, including obligations linked to a prior licensing agreement with MorphoSys, now a subsidiary of Novartis.
Biogen initially gained rights to felzartamab outside Greater China through its acquisition of HI-Bio in July 2024. Since then, the company has advanced the drug into late-stage studies for conditions such as antibody-mediated rejection (AMR) in kidney transplant patients, IgA nephropathy (IgAN), and primary membranous nephropathy (PMN). These diseases represent significant unmet medical needs, particularly in China, where large patient populations are affected.
China is considered a critical market for these indications. IgA nephropathy is the most common form of primary glomerulonephritis and a major cause of kidney failure among young adults in the country. Meanwhile, primary membranous nephropathy has seen rising incidence rates and is a leading contributor to nephrotic syndrome in adults, often progressing to end-stage kidney disease.
The agreement builds on an existing collaboration between the two companies. In 2025, TJ Biopharma joined Biogen-sponsored Phase 3 international multi-center trials evaluating felzartamab in China for IgAN and PMN. The expanded partnership is expected to accelerate development and commercialization efforts in the region.
Biogen will now oversee development, manufacturing, and commercialization of felzartamab in Greater China. However, for the multiple myeloma indication, TJ Biopharma will continue to manufacture the drug at its Hangzhou GMP facility. A Biologics License Application for this indication is currently under review by the National Medical Products Administration.
The deal underscores Biogen’s strategic focus on immunology and rare diseases while reinforcing its commitment to expanding access to innovative therapies in key global markets.