Rare Autoimmune Disease Treatment Secures Funding Ahead of U.S. Approval Application Next Year

Zenas BioPharma, Inc. (Nasdaq: ZBIO) today reported its fourth-quarter and full-year 2025 financial results, alongside highly positive data from the Phase 3 INDIGO trial of obexelimab, its investigational therapy for IgG4-related disease. The company plans to submit a Biologics License Application (BLA) to the U.S. Food and Drug Administration in the second quarter of 2026 and file for marketing approval with the European Medicines Agency in the second half of 2026.

According to the announcement, Zenas BioPharma is targeting fourth-quarter 2026 topline results for the SunStone Phase 2 study in systemic lupus erythematosus. In parallel, the company is advancing ZB014, the Phase 3 program of the BTK inhibitor orelabrutinib in progressive multiple sclerosis, and early-stage assets ZB021 and ZB022.

To fund commercialization and R&D efforts, Zenas BioPharma has secured a five-year, secured multi-tranche loan facility of up to $250 million with a fund managed by Pharmakon Advisors. While operating expenses and net losses are expected to rise significantly in 2025, the company said this financing—together with anticipated milestone payments—supports its cash runway through 2027.

Recently, Zenas BioPharma raised additional capital via a mezzanine debt issuance and a common stock offering. Proceeds will be used to prepare for U.S. commercialization of obexelimab, advance the orelabrutinib Phase 3 trial, and support early clinical development of ZB021. In final INDIGO data announced in January, obexelimab reduced the risk of IgG4-related disease relapse by 56% versus placebo, reinforcing the company’s goal of initiating sequential U.S. and European regulatory reviews in 2026.

Zenas BioPharma is a Nasdaq-listed, clinical-stage biotech specializing in autoimmune therapies. Its lead asset, obexelimab, is a bispecific antibody designed to modulate B-cell function. IgG4-related disease is a rare autoimmune disorder with few approved treatment options, and global pharmaceutical companies are competing to develop novel, mechanism-based antibody therapies in this space.