Chinese biotechnology company Ascletis Pharma Inc (HKEX:1672) on Monday reported positive results from a randomised, double-blind, placebo-controlled 28-day proof-of-concept clinical trial with ASC50 in mild-to-moderate plaque psoriasis patients in the United States.

This Phase I study was designed to evaluate the safety, efficacy and pharmacokinetics of once-daily 200 mg of ASC50 after 28-day treatment in mild-to-moderate plaque psoriasis patients.

According to Ascletis, findings showed a placebo-adjusted reduction of 48.9% in psoriasis area and severity index (PASI) score in mild-to-moderate plaque psoriasis patients after once-daily 200 mg 28-day treatment. Steady-state elimination half-life after 28-day treatment in patients was 6.5 days, supporting potential once-weekly oral dosing.

The placebo-adjusted reduction in PASI score increased to 60.7% and 65.9% 6 days and 15 days, respectively, after the last dose (28th dose). These data also support potential once-weekly oral dosing.

Once-daily 200 mg dosing demonstrated comparable reduction in PASI score to published data on secukinumab, the marketed interleukin-17A (IL-17A) antibody drug.

The data showed strong target engagement after 28-day dosing, indicated by elevated plasma IL-17A levels.

Additionally, once-daily 200 mg 28-day treatment was safe and well tolerated, with no serious adverse events reported and no discontinuation in the study. No alanine aminotransferase (ALT) and aspartate aminotransferase (AST) elevations were observed, and no hepatic safety signal was detected.

ASC50 is an in-house discovered and developed oral small molecule inhibitor targeting IL-17A, an important biologically and commercially validated target for multiple autoimmune and inflammatory diseases, including psoriasis. ASC50 is a new chemical entity (NCE) with a novel scaffold.