Mirum Pharmaceuticals has agreed to acquire Bluejay Therapeutics in a deal worth up to $820m, adding a Phase III liver disease candidate to its portfolio.
According to the agreement, US-based Mirum will pay $250m in cash and $370m in its own stock upfront to buy the private biotech. Bluejay is also in line to receive a further $200m in potential sales-based milestones.
Go deeper with GlobalData
Discover B2B Marketing That Performs
Combine business intelligence and editorial excellence to reach engaged professionals across 36 leading media platforms.
The deal gives Mirum access to brelovitug, Bluejay’s monoclonal antibody (mAb) currently being evaluated in a Phase III trial for chronic hepatitis D, a rare and severe liver infection for which there are no US Food and Drug Administration (FDA)-approved therapies. Gilead’s Hepcludex (bulevirtide) is approved as a hepatitis D treatment in the EU.
Only occuring in people already infected with hepatitis B due to the surface proteins needed for viral replication, chronic hepatitis D is considered the most severe type of chronic viral hepatitis and leads to cirrhosis, liver failure, and liver cancer.
Brelovitug neutralises hepatitis D and hepatitis B virusus by binding to surface antigens, clearing hepatitis B Surface Antigen (HBsAg)-containing particles and activating antigen-specific T cells.
In November 2025, Bluejay reported positive data from a Phase II study evaluating brelovitug in patients with chronic hepatitis D. The drug achieved a 100% virologic response, along with beneficial effects on liver inflammation and viral load reduction.
US Tariffs are shifting - will you react or anticipate?
Don’t let policy changes catch you off guard. Stay proactive with real-time data and expert analysis.
By GlobalDataThe ongoing global AZURE Phase III programme is currently enrolling patients, with top-line data expected in H2 2026. Mirum anticipates submitting an application to the FDA in 2027, with a launch occurring in the same year.
Mirum said it has also secured $200m through a private placement with new and existing healthcare investors to help fund the drug’s development and commercialisation.
Mirum’s commercial portfolio includes Livmarli (maralixibat) for chronic itching due to Alagille syndrome, Cholbam (cholic acid) for bile acid synthesis disorders, and Ctexli (chenodiol) for lipid storage disease cerebrotendinous xanthomatosis.
The latter two products were acquired by Mirum in a buyout of Travere’s bile acid product portfolio for up to $445m in 2023.
Mirum’s CEO Chris Peetz said: “This acquisition fits squarely with what we do best – advancing high-impact medicines for patients with rare diseases through disciplined development, regulatory innovation, and commercial excellence.”
Mirum’s pipeline includes ileal bile acid transporter inhibitor volixibat, which is in two Phase IIb studies (NCT05050136, NCT04663308) for two types of cholangitis. The company also has MRM-3379, a PDE4D inhibitor in a Phase II trial (NCT07209462) for the treatment of fragile X syndrome.
Peetz added: “Brelovitug in hepatitis D leverages our deep expertise in rare liver disease and builds on the relationships we’ve established with key providers through the volixibat and Livmarli programmes.”
