An HBV program built on ingenuity, vision and experience

Our goal is to discover and develop finite and curative therapies for those chronically infected with hepatitis B virus (HBV), and we believe we have unique capabilities that will enable us to bring the first therapeutic innovation in decades and improve cure rates for individuals with chronic HBV infection. Our strong scientific expertise in discovering small molecules targeting the HBV core protein has made us a leader in the field.

HBV—one of the world’s most prevalent diseases

Chronic hepatitis B virus (HBV) infection is a debilitating disease of the liver that afflicts approximately 296 million people worldwide, as estimated by the World Health Organization. HBV is a global epidemic that affects more than twice the number of people than hepatitis C virus (HCV) infection and human immunodeficiency virus (HIV) infection combined—with a higher morbidity and mortality rate. HBV is a leading cause of chronic liver disease and need for liver transplantation, and up to one million people worldwide die every year from HBV-related causes.

The current standard of care for patients with chronic HBV infection is life-long suppressive treatment with medications that reduce, but do not eliminate, the virus, resulting in very low cure rates and enormous unmet need.

Our unique approach attacks HBV at multiple points in the viral replication cycle

Assembly Bio is advancing a number of core inhibitors (CIs), a novel class of oral antivirals, into preclinical and clinical development. Each of these CI product candidates has been derived from distinct and novel chemical scaffolds to optimize their ability to effectively disrupt both viral replication and prevent the establishment and replenishment of new covalently closed circular DNA (cccDNA)—a viral component that drives HBV’s life-long persistence in patients. The current standard of care can only inhibit production of new virus – and may do so incompletely.1

1Marcellin, et al, AASLD 2014, Poster 1861

A pipeline strategy designed to free patients from lifelong therapy

In our relentless pursuit to bring finite and curative treatments to HBV patients in need, our pipeline strategy is focused on three key areas:

  • More potent, next generation core inhibitors
  • Proof-of-concept combinations exploring a core inhibitor with multiple other mechanisms
  • New compounds with novel targets and mechanisms

Potent next generation core inhibitors

Vebicorvir (VBR) is our most advanced CI product candidate, however we continue to develop more potent, next generation CI product candidates. These include ABI-H3733 (3733) and our recently nominated candidate ABI-4334 (4334). A Phase 1 study of 3733 is ongoing and 4334, which has a potential, best-in-class profile, including greater potency against cccDNA formation is expected to initiate clinical studies in 2022.

Proof of concept combinations with multiple mechanisms

Assembly Bio is exploring the potential to combine three or more therapeutic candidates with differing mechanisms of action, an approach that has proven successful in the treatment of other diseases, including chronic viral infections. Our first two triple combination studies in individuals with chronic HBV infection include a Phase 2 clinical trial evaluating the addition of interferon to the antiviral backbone of VBR and standard-of-care nucleos(t)ide (Nrtl) therapy and a Phase 2 clinical trial evaluating the addition of Arbutus Biopharma’s RNAi candidate (AB-729), to the VBR+Nrtl antiviral backbone

Research programs advancing new compounds with novel targets and mechanisms

Our research team is focused on proprietary research that has the potential to accelerate progress toward HBV cures and to discover novel antivirals to treat other serious viral diseases. We are currently advancing an early-stage program evaluating a novel small molecule approach to inhibit viral entry for HBV and hepatitis delta virus (HDV), which is estimated to impact approximately 5 percent of those chronically infected with HBV – approximately 12 million people globally. We are also currently exploring an additional novel research program against an undisclosed HBV target that we believe is differentiated in the field, as well as initiatives targeting other viruses.

More information about our clinical trials can be found at