Mirum Completes Bluejay Acquisition, Expands Rare Liver Disease Pipeline

Mirum Pharmaceuticals, Inc. has completed its acquisition of Bluejay Therapeutics, a privately held biotechnology company focused on viral and liver diseases, marking a significant step in Mirum’s strategy to expand its rare disease portfolio. The transaction brings Mirum worldwide rights to brelovitug, a late-stage monoclonal antibody being developed for chronic hepatitis delta virus (HDV), a rare and severe liver disease with no FDA-approved treatments currently available in the United States.

With the acquisition finalized, Mirum’s leadership emphasized a shift toward execution and integration. Chief Executive Officer Chris Peetz said the company’s immediate priorities include incorporating the Bluejay team into Mirum and advancing the ongoing AZURE Phase 3 clinical program for brelovitug. The company is also preparing for potential regulatory submissions and future commercial launches, pending trial outcomes.

Brelovitug is a fully human monoclonal antibody and represents one of the most advanced investigational therapies for HDV. The drug has received Breakthrough Therapy designation from the U.S. Food and Drug Administration and PRIME designation from the European Medicines Agency, reflecting its potential to address a serious unmet medical need. It is currently being evaluated in the global AZURE Phase 3 registrational study, with topline data expected in the second half of 2026.

Mirum stated that brelovitug aligns closely with its existing focus on rare diseases, particularly rare liver disorders, an area where the company has established development and commercial expertise. According to Peetz, Mirum’s global infrastructure and experience are expected to support efficient development and, if approved, successful commercialization of the therapy for patients living with HDV.

Under the terms of the agreement, Mirum acquired all outstanding shares of Bluejay Therapeutics in exchange for a combination of cash and Mirum common stock. The transaction also includes the potential for additional tiered, sales-based milestone payments, subject to future performance.

Alongside the acquisition, Mirum completed previously announced private placement financings involving both existing and new healthcare investors. These financings generated approximately $268.5 million in gross proceeds, which the company plans to use to support ongoing clinical development and future commercial activities related to brelovitug. Mirum also noted that it is currently evaluating strategic options for Bluejay’s other investigational programs, as it continues to build its rare disease pipeline.