Mirum Pharmaceuticals Expands Portfolio With Bluejay Therapeutics Acquisition

Transaction Overview and Terms

• Mirum Pharmaceuticals Inc., a specialty pharmaceutical company focused on rare diseases, has reached an agreement to acquire Bluejay Therapeutics, a privately held biotechnology firm specializing in viral and liver diseases.

• The initial value of the acquisition, which covers all outstanding shares of Bluejay Therapeutics, is $620 million, composed of $250 million in cash and $370 million in Mirum common stock.

• The definitive agreement also includes potential tiered sales-based milestone payments of up to an additional $200 million in cash.

• The transaction has been approved by the Boards of Directors of both corporations and is anticipated to close in the first quarter of 2026, subject to regulatory approvals and other customary closing conditions.

Strategic Impact and Key Asset

• The acquisition grants Mirum worldwide rights to brelovitug, a late-stage, fully human monoclonal antibody.

• Brelovitug is designated for the treatment of chronic hepatitis delta virus (HDV), recognized as the most severe form of viral hepatitis. The product candidate has received Breakthrough Therapy and PRIME (Priority Medicines) designations from regulatory bodies.

• This addition is expected to solidify Mirum’s leadership in the rare disease space, building upon its existing expertise in rare liver disorders, and providing a fourth potential registrational data readout for the company over the coming 18 months.

Brelovitug Clinical Development Status

• Brelovitug is currently being evaluated in the global registrational Phase 3 clinical program, designated AZURE, which is actively enrolling patients.

• Prior Phase 2 studies demonstrated potent antiviral activity against HDV, achieving a 100% HDV RNA response, alongside improved liver enzyme levels and a favorable safety profile (with injection-site erythema being the most commonly reported adverse event).

• Top-line data from the Phase 3 program is expected in the second half of 2026, with a potential Biologics License Application (BLA) submission and market launch anticipated in 2027.

Executive Perspectives

• Chris Peetz, CEO of Mirum Pharmaceuticals, commented that the acquisition aligns with the company’s core focus of advancing high-impact medicines for rare disease patients through disciplined development and regulatory innovation. He highlighted that brelovitug leverages Mirum’s deep expertise in rare liver disease and existing relationships with key healthcare providers.

• Keting Chu, Founder and CEO of Bluejay Therapeutics, expressed confidence in brelovitug’s potential to redefine HDV treatment. He stated that Mirum’s leadership in rare diseases, commitment to the rare liver community, and commercialization capabilities make them the ideal company to advance the program globally.