Brelovitug Meets Primary Endpoint in Phase 3 HDV Clinical Trial

Patients receiving brelovitug in the AZURE-1 study saw their clinical responses deepen well beyond the 24-week mark, according to new data presented at The Liver Meeting 2026 in Denver.

The results suggest the treatment may offer a more convenient alternative for managing chronic hepatitis D (HDV) than current options.

As reported by HCPLive, the phase 2b study showed that the composite primary endpoint—which combines virologic response with the normalization of alanine aminotransferase (ALT) levels—continued to improve as treatment progressed. By week 48, the composite endpoint rose to 55% in both the weekly 300 mg dose group and the 900 mg every-4-weeks dose group.

For patients on the weekly 300 mg dose, the proportion of participants with HDV RNA below the lower limit of quantification climbed from 45% at week 24 to 80% by week 48. Those receiving the 900 mg dose every four weeks saw their levels move from 10% to 40% over that same period.

Changes in treatment methods

The emergence of brelovitug comes on the heels of a major regulatory milestone. In May 2026, the U.S. Food and Drug Administration granted accelerated approval to bulevirtide (Hepcludex), marking it as the first therapy for chronic HDV. However, the dosing schedules differ significantly.

Hepatitis D Treatment: Brelovitug Results and HDV Screening

While bulevirtide requires once-daily administration, brelovitug offers the potential for weekly or even monthly dosing.

“brelovitug should change the CHD treatment landscape,” Dieterich said, citing the convenience of weekly or monthly dosing compared with the once‑daily bulevirtide (Hepcludex), which received accelerated FDA approval in May 2026 as the first therapy for chronic HDV.

Clinical observations from practitioners suggest the impact may extend beyond viral suppression. Dieterich noted that patients in his practice have reported feeling stronger, gaining weight, and generally feeling better while on the treatment.

Safety data from the trial remained largely stable. Through week 24, 17% of participants treated with brelovitug experienced mild injection site reactions, and one person reported mild flu-like symptoms. There were no treatment-related serious adverse events or discontinuations caused by adverse events reported during that period. A single serious adverse event involving a hospitalization to manage ascites was noted later in the trial.

The screening gap remains a hurdle

Despite these therapeutic advancements, many people living with hepatitis B are never screened for the more aggressive hepatitis D virus.

Data highlights the scale of this issue. A recent analysis revealed that fewer than 10% of patients with hepatitis B in New York City had ever been tested for HDV.

Dieterich emphasized that the standard of care should be broader, stating, “Everybody who’s surface antigen positive should be tested for delta hepatitis.”

The following table compares the clinical response rates observed at the 24-week mark during the AZURE-1 study:

Dosing Group	Virologic Response	ALT Normalization	Composite Endpoint
300 mg weekly	100%	45%	45%
900 mg every 4 weeks	75%	40%	35%
Delayed treatment	0%	8%	0%

Looking ahead, Mirum Pharmaceuticals intends to move toward formal regulatory approval. The company plans to submit a biologics license application in the first half of 2027, following the successful meeting of primary endpoints in the phase 3 portion of the AZURE-1 trial in September 2026.

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