Zenas BioPharma Secures $300M Royalty Deal for Obexelimab FDA Approvals

On September 2, 2025, Zenas BioPharma entered a funding agreement with Royalty Pharma for up to $300 million to advance the autoimmune therapy obexelimab through late-stage trials and towards FDA approvals2345.

The deal includes an upfront payment of $75 million and up to three milestone payments of $75 million each, contingent upon:
the success of the Phase 3 INDIGO trial for IgG4-Related Disease, FDA approval for obexelimab in IgG4-RD, and FDA approval for systemic lupus erythematosus (SLE)235.

Royalty Pharma will receive a 5.5% royalty on worldwide net sales of obexelimab, as well as other payments tied to commercialization in certain partnered geographies24.

Obexelimab is a bifunctional monoclonal antibody that binds both CD19 and FcγRIIb, designed to inhibit B cell activity without depleting cells, aiming to broadly address pathogenic B cell roles in chronic autoimmune diseases2.

The funding directly supports obexelimab’s potential launch for IgG4-Related Disease in the first half of 2027, pending successful trial outcomes and regulatory approvals5.

Sources:

2. https://www.globenewswire.com/news-release/2025/09/02/3142507/0/en/Zenas-BioPharma-and-Royalty-Pharma-Enter-into-Obexelimab-Funding-Agreement-for-up-to-300-Million.html

3. https://www.sec.gov/Archives/edgar/data/1953926/000110465925085982/tm2524961d1_8k.htm

4. https://www.tipranks.com/news/company-announcements/zenas-biopharma-secures-300m-funding-for-obexelimab

5. https://www.ainvest.com/news/zenas-biopharma-secures-300-million-funding-obexelimab-development-potential-igg4-launch-2509/