Biogen Secures Global Control of Felzartamab in $850M China Deal

CAMBRIDGE, Mass. and HANGZHOU, China – April 20, 2026 – Biogen Inc. has solidified its global ambitions for the promising immunology asset felzartamab, acquiring the exclusive rights for the Greater China region from TJ Biopharma in a deal potentially worth up to $850 million. The agreement gives Biogen complete worldwide ownership of the investigational antibody, which it views as a potential 'pipeline-in-a-product' for a range of immune-mediated diseases.

The deal structure includes a $100 million upfront payment to TJ Biopharma, which will be recorded by Biogen as an R&D expense in the second quarter of 2026. TJ Biopharma is also eligible to receive up to an additional $750 million in commercial and sales-based milestone payments, plus tiered royalties on future net sales within Greater China. This move completes Biogen's strategic consolidation of the asset, which began with its acquisition of HI-Bio in July 2024, securing the drug's rights outside of China.

A Global Strategy Comes Full Circle

This transaction represents the final piece of a global puzzle for Biogen, transforming felzartamab from a regionally licensed asset into a wholly-owned global priority. By bringing the Greater China rights in-house, Biogen can now execute a unified worldwide development and commercialization strategy for the CD38-directed antibody, which is currently in Phase 3 trials for several conditions with significant unmet needs.

"This deal is important to Biogen as it further expands the global opportunity for felzartamab, a potential pipeline-in-a-product with broad applicability across a range of immune-mediated conditions," said Fraser Hall, President of Biogen's Intercontinental Region. "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."

The acquisition underscores Biogen's deepening commitment to the Chinese market, a region the company views as a critical engine for growth and innovation. China is home to one of the largest patient populations globally for key indications targeted by felzartamab, including IgA nephropathy (IgAN) and primary membranous nephropathy (PMN). IgAN is the most common primary kidney disease in China and a leading cause of kidney failure in young adults, making the development of new therapies a public health priority.

Validating a Chinese Biotech Blueprint

For TJ Biopharma, the agreement is a significant validation of its 'fast-to-market' and 'tiered value realization' business model. The Hangzhou-based company has successfully advanced felzartamab within China, notably submitting a Biologics License Application (BLA) for the drug as a treatment for multiple myeloma in December 2024, which is currently under review by China's National Medical Products Administration (NMPA).

The deal provides TJ Biopharma with a substantial infusion of non-dilutive capital to fuel its internal pipeline, which includes next-generation antibody conjugates. The structure of the deal, with a large upfront payment and significant downstream milestones and royalties, allows the company to realize immediate value while participating in the long-term success of the asset.

"With Biogen's strong global capabilities and a proven track record of commercial success in the region, we are confident that they are the right partner to progress felzartamab in this important market," stated Dr. Lili Qian, General Manager of TJ Biopharma. "This transaction sharpens our strategic focus and validates our business models. It generates near- and long-term value for TJ Bio, supporting continued investment in our differentiated pipeline."

Under the terms, TJ Biopharma will maintain a strategic role, serving as the manufacturer for felzartamab for the multiple myeloma indication from its GMP facility in Hangzhou, while Biogen will lead all post-approval and commercial activities.

The Promise of a 'Pipeline-in-a-Product'

Felzartamab is an investigational human monoclonal antibody that targets CD38, a protein found on the surface of plasma cells. By depleting these cells, the drug aims to reduce the pathogenic antibodies that drive a variety of autoimmune diseases and certain cancers. Its potential to treat multiple distinct conditions is what gives it the coveted 'pipeline-in-a-product' status.

The drug is being evaluated in global Phase 3 trials for several serious conditions:

• IgA Nephropathy (IgAN): A chronic kidney disease where pathogenic IgA antibodies cause inflammation and kidney damage. The market for IgAN treatments in China is projected to grow exponentially, reaching over $170 million by 2032.
• Primary Membranous Nephropathy (PMN): An autoimmune disease that is a leading cause of nephrotic syndrome in Chinese adults.
• Antibody-Mediated Rejection (AMR): A major cause of organ transplant failure in kidney recipients.
• Multiple Myeloma (MM): A cancer of plasma cells, for which a BLA is already under review in China.

The agreement builds on an existing collaboration established in April 2025, where TJ Bio joined Biogen-sponsored international Phase 3 trials for IgAN and PMN in China. Biogen will now assume full leadership of development, manufacturing, and commercialization for all immunology indications in the region.

Navigating a Competitive Landscape

While felzartamab holds significant promise, it will enter a competitive and dynamic therapeutic landscape. In multiple myeloma, it will face established CD38 inhibitors like Janssen's daratumumab and Sanofi's isatuximab. Biogen will need to carve out a niche for the drug, potentially leveraging a differentiated profile or clinical data from the Chinese patient population.

In the IgAN space, the field has seen recent approvals and a flurry of development activity. Therapies like Calliditas's TARPEYO and Travere's FILSPARI are already on the market, and numerous other candidates targeting different biological pathways are advancing in late-stage trials. Felzartamab's unique mechanism of directly depleting CD38+ plasma cells could offer a distinct advantage for certain patient populations.

The consolidation of global rights under a single, well-capitalized entity like Biogen is intended to streamline development and maximize the drug's potential across these varied indications. This unified approach could accelerate regulatory filings and ensure a coordinated global launch strategy, ultimately benefiting patients awaiting new treatment options. The transaction is a clear signal of Biogen's confidence in felzartamab's scientific and commercial potential as a cornerstone of its expanding immunology franchise.