Biogen has entered into an agreement with TJ Biopharma (TJ Bio) to acquire exclusive rights to felzartamab in the Greater China region, further extending its control of the investigational therapy to worldwide.
Under the terms of the deal, Biogen will pay $100m upfront, with TJ Bio eligible for up to $750m in commercial and sales milestone payments, bringing the total potential value to $850m.
The agreement also includes a small percentage share in royalties on net sales in Greater China, the geographical area comprising mainland China, Hong Kong, Macau and Taiwan.
Felzartamab is currently being evaluated in global phase 3 clinical studies across multiple immune-mediated diseases. The monoclonal antibody targets CD38, a protein expressed on plasma cells and other immune cells and is being investigated for conditions including antibody-mediated rejection in kidney transplant recipients, IgA nephropathy and primary membranous nephropathy.
Biogen previously acquired worldwide rights to felzartamab excluding Greater China through its acquisition of HI-Bio in 2024. The latest agreement extends those rights globally and adds responsibility for development, manufacturing and commercialisation in the region.
Fraser Hall, President of Biogen’s intercontinental region, said the deal expands the potential reach of the therapy and supports the company’s immunology pipeline. “We look forward to continuing to evaluate felzartamab in Phase 3 studies and the opportunity to bring this potentially differentiated treatment to patients in the Greater China region,” he said.
The agreement builds on an existing collaboration between the two companies. In 2025, TJ Bio joined two Biogen-sponsored Phase 3 international multicentre trials evaluating felzartamab in IgA nephropathy and primary membranous nephropathy in China.
Both conditions represent significant unmet need in the region. IgA nephropathy is a leading cause of end-stage kidney disease in young adults in China, while primary membranous nephropathy is an increasingly common cause of adult nephrotic syndrome.
As part of the deal, Biogen will assume responsibility for milestone and royalty obligations linked to a prior licensing agreement with MorphoSys, now a subsidiary of Novartis. TJ Bio will continue to manufacture felzartamab for multiple myeloma at its Hangzhou facility, while a biologics licence application for the monoclonal antibody to be used to treat the condition remains under review in China.