By VETTAPHARMA reporter – Derek Roche: Gilead Sciences’ Hepcludex (bulevirtide‑gmod) received U.S. Food and Drug Administration approval May 22, 2026 to treat chronic hepatitis delta virus (HDV) infection in adults without cirrhosis or with compensated cirrhosis. The approval is the first FDA‑approved therapy for chronic HDV, a disease that accelerates liver fibrosis, raises hepatocellular carcinoma risk, and can lead to liver failure and death.
The decision was supported by data from the multi‑center, randomized, open‑label Phase 3 MYR301 trial, which compared immediate Hepcludex 8.5 mg once daily for 144 weeks versus delayed treatment (48‑week observational period then 96 weeks of Hepcludex). The primary combined response at week 48—defined as undetectable HDV RNA (below the lower limit of quantification, 50 IU/mL, target not detected) or ≥2 log₁₀ IU/mL decline from baseline plus ALT normalization—was 48% with Hepcludex versus 2% in the delayed group.
Virologic outcomes improved with continued therapy: undetectable HDV RNA rates were 20% at week 48, 36% at week 96, and 50% at week 144 in the Hepcludex arm. These numerical endpoints underpinned the FDA’s accelerated approval, granted after review of the trial’s virologic and biochemical response data.
Hepcludex previously received Breakthrough Therapy and Orphan Drug designations and was reviewed under priority review and the Accelerated Approval pathway to expedite access for a serious condition with unmet need.
The product label includes a boxed warning that discontinuation may precipitate severe acute exacerbations of HDV and HBV infection. Reported adverse events include hypersensitivity (including anaphylaxis), injection‑site reactions, headache, abdominal pain, fatigue, and pruritus. Clinicians will need to monitor patients for HBV/HDV flares when changing or stopping therapy.
Because HDV infection occurs only in persons with hepatitis B virus, the approval reinforces the public‑health value of HBV vaccination as primary prevention. For patients, Hepcludex provides the first targeted therapeutic option demonstrating meaningful virologic and biochemical responses over multi‑year follow‑up, with potential to slow progression to advanced liver disease and improve treatment access for a defined population. Commercially, the approval opens a specialty indication for Gilead with a clearly defined patient base and creates opportunities for access programs and further HDV development.
