Zenas BioPharma Highlights Obexelimab Phase 3 Win, Targets Q2 BLA Filing

CEO Lonnie Moulder discusses clinical progress, market research, and upcoming regulatory milestones for the company's IgG4-related disease treatment.

Published on Feb. 18, 2026

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Zenas BioPharma CEO Lonnie Moulder provided an update on the company's pipeline, with a focus on obexelimab for IgG4-related disease (IgG4-RD). Moulder highlighted positive top-line results from the INDIGO Phase 3 study and data from the open-label extension, as well as plans to file a Biologics License Application (BLA) in the U.S. in Q2 2026 and in Europe in the second half of the year. He also discussed market research, administration preferences, safety considerations, and the commercial opportunity for obexelimab.

Why it matters

Obexelimab represents a potential new treatment option for patients with IgG4-RD, a rare and complex autoimmune condition that can affect multiple organ systems. The positive Phase 3 results and Zenas' plans to file for regulatory approvals in major markets suggest the drug could become an important new therapy if approved, providing an alternative to current treatment approaches.

The details

In the INDIGO Phase 3 study, obexelimab met the primary endpoint of time to first IgG4-RD flare, with about 92% of patients in the open-label extension remaining flare-free at six months. Moulder said serious adverse events were not greater than placebo, and injection site reactions were similar. Market research indicated that clinicians and patients preferred the weekly subcutaneous administration over an every-six-month IV regimen. Zenas estimates a potential $3-4 billion U.S. opportunity for obexelimab in IgG4-RD, based on an estimated 20,000 diagnosed patients and an 80% treatment rate.

  • Zenas plans to file a U.S. BLA for obexelimab in the second quarter of 2026.
  • Zenas plans to file for European approval in the second half of 2026.

The players

Zenas BioPharma

A clinical-stage biotechnology company focused on the discovery and development of novel therapies in oncology and infectious diseases.

Lonnie Moulder

Chief Executive Officer of Zenas BioPharma.

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What they’re saying

“We must not let individuals continue to damage private property in San Francisco.”

— Robert Jenkins, San Francisco resident (San Francisco Chronicle)

The takeaway

Zenas BioPharma's positive Phase 3 results and plans to file for regulatory approvals for obexelimab in IgG4-RD represent an important milestone in the development of new treatment options for this rare and complex autoimmune condition. The company's market research and focus on safety and administration preferences suggest it is well-positioned to potentially bring a differentiated therapy to patients if approved.