Assembly Biosciences Begins Phase 1a Trial of Oral Entry Inhibitor ABI-6250 for Hepatitis Delta Virus

Assembly Biosciences, Inc., a biotechnology company located in South San Francisco, has made a significant advance in its efforts to combat serious viral diseases. The company has commenced the Phase 1a clinical trial for ABI-6250, a potential oral treatment targeting the hepatitis delta virus (HDV). The initial participant has been dosed in this trial, which aims to assess various aspects of the candidate drug.

The study is designed to evaluate the safety, tolerability, and pharmacokinetics of ABI-6250. It will be conducted in healthy volunteers and involve both single and multiple ascending dose cohorts. An additional focus of the study is on serum bile acids, which will serve as a biomarker to show how well ABI-6250 engages its target, the sodium taurocholate cotransporting polypeptide (NTCP) used by HDV to infect liver cells. Assembly Biosciences anticipates sharing the results of this study by the third quarter of 2025.

Currently, there is only one approved treatment for chronic HDV infection in Europe, which involves daily injections of a peptide inhibitor of NTCP. There are no approved treatments for this condition in the United States. The existing therapy has been linked to clinically tolerable elevations in serum bile acids.

Dr. Anuj Gaggar, Chief Medical Officer of Assembly Biosciences, highlighted the potential of ABI-6250 to become the first oral treatment for chronic HDV, a severe chronic viral infection with limited treatment options. Chronic HDV is noted as the most aggressive form of viral hepatitis, with a significant percentage of affected individuals developing cirrhosis within a decade. The initiation of clinical trials for ABI-6250 marks a promising step toward simplifying the treatment of HDV.

Preclinical studies have shown that ABI-6250 is highly potent at low concentrations across various HDV genotypes in laboratory settings. It has selective activity for NTCP over other bile acid transporters and a pharmacokinetic profile that supports once-daily oral dosing. However, ABI-6250 remains an investigational product and has not received regulatory approval yet, meaning its safety and efficacy are still to be established.

The Phase 1a trial, designated as ABI-6250-101, is a randomized, double-blinded, and placebo-controlled study. Participants will be randomly assigned to receive either ABI-6250 or a placebo across up to ten different cohorts, divided into single-dose and multiple-dose groups. The multiple-dose cohorts will involve repeated administration of the drug over a period of ten days.

In addition to monitoring safety, tolerability, and pharmacokinetics, the trial will measure changes in serum bile acid levels to further understand NTCP engagement. The findings from this trial will be instrumental in determining appropriate doses for future clinical studies.

Assembly Biosciences is committed to developing innovative small-molecule therapies aimed at transforming the approach to serious viral diseases and enhancing patient outcomes. The company has a strong leadership team with expertise in virology and is dedicated to addressing the challenges faced by patients with chronic viral infections, including those caused by herpesvirus, hepatitis B virus, and hepatitis delta virus.