Ascletis Pharma Inc. announces the latest phase IIb clinical trial results of subcutaneous PD-L1 antibody ASC22 (envafolimab) in patients with chronic hepatitis B (CHB) 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).
The interim report is based on a randomized, single-blind, multi-center phase IIb clinical trial to assess the efficacy and safety of ASC22 in treatment of CHB patients (ClinicalTrials.gov Identifier: NCT04465890). In 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 2 weeks (Q2W) plus nucleos(t)ide analogs (NAs) for 24-week and then followed for another 24 weeks.
The key findings from the phase IIb clinical study on ASC22: 42.9% patients with baseline HBsAg =100 IU/mL (n=7) obtained sustained HBsAg loss; ALT flares were observed on 21% patients in ASC22 group (n=48) while none in 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 Four after two doses of ASC22 and experienced a transient seroconversion of anti-HBs at Week 28. This patient stopped NAs treatment three days after 24-week treatment of ASC22, and HBsAg still remained negative until end of the study; Most adverse events (AEs) (97.5%) were Grade 1-2, and no study drug-related serious adverse event (SAE) was reported.
