Header Ab 101


AB-101 is our oral PD-L1 inhibitor.

The immune system of HBV chronically infected patients is tolerized to recognize the virus or infected cells. To achieve a functional cure and long-term HBV viral control, it is believed that highly functional HBV specific T-cells are required.

Immune checkpoints such as PD-1/PD-L1 play an important role in the induction and maintenance of immune tolerance and in T-cell activation.   

Our hypothesis

We hypothesized that one approach to reawaken HBV-specific T-cells is to block the PD-1/PD-L1 protein-protein interaction, and potentially break HBV-specific immune tolerance. Support for this approach was observed in preclinical animal model studies where checkpoint blockade in combination with other direct-acting antivirals led to both DNA clearance and sustained viral suppression.   

Based on in vitro potency, immune restoration, in vivo efficacy, selectivity and safety, we selected AB-101 as a lead PD-L1 inhibitor candidate. AB-101 is currently being evaluated in a Phase 1a/1b clinical trial.

We believe AB-101 may have the following important advantages:

  • Oral administration with limited competition
  • Liver targeted
  • Designed to reduce systemic safety issues seen with Antibodies
  • Allows controlled checkpoint blockade
  • Potential to reawaken HBV-tolerized host immune system
  • Sub-nM potency in preclinical studies

Learn more about AB-101 in practice.