Mirum's brelovitug hits primary endpoint in Phase 3 AZURE-4 hepatitis delta trial

What's the news? On 10 November 2026, Mirum Pharmaceuticals announced that its experimental antibody brelovitug met the primary endpoint in AZURE-4, the second of two Phase 3 trials supporting a US filing for chronic hepatitis delta, the most severe form of viral hepatitis.

The results: At week 24, 59% of patients on brelovitug 300 mg once weekly and 44% on 900 mg every four weeks achieved the combined goal of a strong drop in virus levels plus normalisation of liver enzymes (ALT), versus 0% in the delayed-treatment group (p≤0.0001 for both doses). No patients in the delayed-treatment arms of either AZURE study reached the endpoint. Longer-term data presented at the AASLD Liver Meeting showed all 15 patients with cirrhosis treated for up to 108 weeks achieved both goals.

Why it matters: Hepatitis delta virus only infects people already carrying hepatitis B and is the most aggressive form of viral hepatitis, often leading to rapid liver damage. Brelovitug is a fully human antibody that latches onto the surface protein (HBsAg) shared by hepatitis B and delta viruses, neutralising them and clearing viral debris from the blood. It holds FDA Breakthrough Therapy and Orphan Drug designations. With AZURE-1 (positive in September 2026) and now AZURE-4, Mirum plans to submit a Biologics License Application to the US FDA in the first half of 2027, with a potential US launch in Q4 2027. The drug was well tolerated with no new safety signals; the most common side effect was flu-like illness after the first dose.

Read more: Mirum Pharmaceuticals, 10 November 2026