08:35 AM EDT, 09/02/2025 (MT Newswires) -- Zenas BioPharma ( ZBIO ) and Royalty Pharma ( RPRX ) said Tuesday that the latter will offer up to $300 million in financing in exchange for a royalty on sales of monoclonal antibody obexelimab.

Obexelimab is in phase 3 development to treat immunoglobulin G4-related disease (IgG4-RD), and phase 2 development for relapsing multiple sclerosis and systemic lupus erythematosus (SLE), the companies said.

Under the deal, Royalty Pharma ( RPRX ) will receive a 5.5% royalty on global net sales of obexelimab by Zenas in exchange for an upfront payment of $75 million and three additional payments of $75 million based on the achievement of certain benchmarks.

Zenas said the financing will support a potential commercial roll out of obexelimab for IgG4-RD in H1 2027, subject to the US Food and Drug Administration approval.