China-based Ascletis Pharma Inc. (HKG: 1672) presented the latest results of a Phase IIb clinical study for its subcutaneous PD-L1 antibody ASC22 (envafolimab) in patients with chronic hepatitis B virus (cHBV) at an oral parallel session of the International Liver Congress 2022 (ILC 2022) held by the European Association for the Study of the Liver (EASL).
Study Design
The interim report is based on a randomized, single-blind, multi-center Phase IIb clinical trial assessing the efficacy and safety of ASC22 in the treatment of CHB patients (ClinicalTrials.gov Identifier: NCT04465890). In the 1.0 mg/kg ASC22 cohort, 75 CHB patients were randomized to be treated with 1.0 mg/kg ASC22 (n=60) or placebo (PBO, n=15) once every two weeks (Q2W) plus nucleos(t)ide analogs (NAs) for 24-weeks, followed by another 24 weeks.
Key Findings
- 42.9% of patients with baseline HBsAg ≤100 IU/mL (n=7) obtained sustained HBsAg loss.
- ALT flares were observed in 21% of patients in the ASC22 group (n=48), and none in the PBO group.
- Patients with ALT flares had more HBsAg reduction. Among the three patients with sustained HBsAg loss, two experienced ALT flares.
- One patient obtained sustained HBsAg loss starting at week 4 after 2 doses of ASC22, and experienced a transient seroconversion of anti-HBs at week 28. This patient stopped NAs treatment 3 days after 24 weeks of ASC22 treatment, and HBsAg remained negative until the end of the study.
- Most adverse events (97.5%) were Grade 1-2, and no study drug-related serious adverse event (SAE) was reported.-Fineline Info & Tech
