Royalty Pharma and Zenas BioPharma Enter Into Obexelimab Funding Agreement for Up to $300 Million
Initial $75 million to fund the potential U.S. commercial launch of obexelimab for the treatment of IgG4-Related Disease
Additional $150 million associated with the upcoming results of the obexelimab Phase 3 INDIGO trial and FDA approval for the treatment of IgG4-Related Disease
NEW YORK and WALTHAM, Mass., Sept. 02, 2025 (GLOBE NEWSWIRE) -- Royalty Pharma plc (NASDAQ:RPRX) and Zenas BioPharma, Inc. (NASDAQ:ZBIO) today announced that Royalty Pharma will provide up to $300 million in funding in exchange for a royalty on sales of obexelimab.
"We are delighted to partner with Zenas as they develop obexelimab in IgG4-RD and other autoimmune diseases," said Pablo Legorreta, founder and CEO of Royalty Pharma. "There is clear unmet need in IgG4-RD where obexelimab, with its exciting novel B cell modulating mechanism of action, has demonstrated compelling proof-of-concept. IgG4-RD represents a potential blockbuster opportunity for obexelimab. This agreement builds on an already record year for Royalty Pharma in announced value of synthetic royalty transactions, reflecting the compelling advantages this funding paradigm offers to innovative biotech companies. We look forward to supporting the Zenas team as they advance their broad development program to bring this important new treatment to patients in need."
"We are very pleased to partner with Royalty Pharma as we rapidly advance our broad obexelimab program through late-stage development and into global commercialization. This transaction underscores our conviction in the potential of obexelimab as a franchise molecule and provides us with financial flexibility to rapidly advance our clinical programs and fund the commercial launch of obexelimab if approved for the treatment of IgG4-RD," said Lonnie Moulder, Founder and Chief Executive Officer of Zenas. "We are committed to bringing obexelimab to as many patients living with autoimmune diseases as possible and look forward to our upcoming key milestones, including the topline results from our pivotal Phase 3 trial in IgG4-RD expected around year-end, our Phase 2 trial in Relapsing Multiple Sclerosis expected early in the fourth quarter of this year and our Phase 2 trial in Systemic Lupus Erythematosus expected in mid-2026."
Obexelimab is an investigational bifunctional monoclonal antibody designed to inhibit B cell function by binding to both CD19 and FcγRIIb and is in Phase 3 development for the treatment of Immunoglobulin G4-Related Disease (IgG4-RD), and Phase 2 development for Relapsing Multiple Sclerosis (RMS) and Systemic Lupus Erythematosus (SLE). This financing will support obexelimab development and a potential IgG4-RD commercial launch in the first half of 2027, subject to approval by the U.S. Food and Drug Administration (FDA).
Transaction Terms
Under the agreement Zenas will receive up to $300 million, consisting of an upfront payment of $75 million, and three additional payments of $75 million each upon 1) achievement of defined success criteria in the Phase 3 INDIGO trial of obexelimab in IgG4-RD (expected around the end of this year), 2) U.S. FDA approval of obexelimab for IgG4-RD, and 3) U.S. FDA approval of obexelimab for SLE. In exchange, Royalty Pharma will receive a 5.5% royalty on worldwide net sales of obexelimab by Zenas and its affiliates and certain other payments associated with the commercialization of obexelimab in partnered geographies.
Advisors
Evercore acted as exclusive financial advisor and Ropes & Gray LLP acted as legal advisor to Zenas BioPharma. Goodwin Procter LLP and Maiwald GmbH acted as legal advisors to Royalty Pharma.
About Obexelimab
Obexelimab is a bifunctional monoclonal antibody designed to bind both CD19 and FcγRIIb, which are broadly present across B cell lineage, to inhibit the activity of cells that are implicated in many autoimmune diseases without depleting them. This unique mechanism of action and self-administered, subcutaneous injection regimen may broadly and effectively address the pathogenic role of B cell lineage in chronic autoimmune disease.
Obexelimab has been evaluated in five completed clinical trials in a total of 198 subjects who received obexelimab either as an intravenous infusion or as a subcutaneous injection. Obexelimab was well tolerated and demonstrated pharmacologic activity across these five clinical trials, providing the Company an initial clinical proof of concept for obexelimab as a potent B cell inhibitor for the treatment of patients living with certain autoimmune diseases. Currently, Zenas is conducting multiple Phase 2 and Phase 3 trials of obexelimab in several autoimmune diseases including Immunoglobulin G4-Related Disease, Relapsing Multiple Sclerosis and Systemic Lupus Erythematosus.
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