Hong Kong – – September 28, 2026 -- Ascletis Pharma Inc. (HKEX: 1672) reported a 48.9% placebo-adjusted reduction in psoriasis area and severity index (PASI) scores from a 28-day U.S. proof-of-concept trial of ASC50, an oral small molecule IL-17A inhibitor positioned as a needle-free alternative to injectable antibody therapies for plaque psoriasis.
Once-daily 200 mg dosing matched published efficacy benchmarks for injectable IL-17A antibody secukinumab
The randomized, double-blind, placebo-controlled Phase I study (NCT07024602) enrolled mild-to-moderate plaque psoriasis patients who received once-daily 200 mg oral ASC50 for 28 days. Ascletis said the PASI reduction was comparable to published secukinumab data, though the comparison was not conducted head-to-head.
6.5-day half-life data support a shift toward once-weekly oral dosing
Steady-state elimination half-life after 28 days of treatment reached 6.5 days. The placebo-adjusted PASI reduction climbed further post-treatment, hitting 60.7% at six days and 65.9% at fifteen days after the final (28th) dose, results the company said reinforce the case for a once-weekly oral regimen.
Elevated plasma IL-17A levels confirmed target engagement of the novel scaffold
Ascletis reported strong target engagement following 28-day dosing, evidenced by elevated plasma interleukin-17A levels. ASC50 is a new chemical entity with a proprietary scaffold, discovered and developed in-house by the company.
No hepatic safety signal emerged across 28 days of daily dosing
All adverse events were mild (Grade 1) and transient, with no serious adverse events and no patient discontinuations. Investigators observed no elevations in alanine aminotransferase (ALT) or aspartate aminotransferase (AST), and no hepatic safety signal was detected.
Jinzi Jason Wu, Founder, Chairman and CEO of Ascletis, said the data support ASC50's potential as a first-in-class, best-in-class oral IL-17A inhibitor that could offer patients a needle-free alternative to injectable antibody therapies with once-weekly dosing.