AC-201, an TYK2/JAK1 Inhibitor, Hits PASI-75 at Week 12 in Psoriasis Phase 2 Trial

Positive Phase 2 data demonstrated that AC-201, an oral, highly selective TYK2/JAK1 inhibitor, brought a ≥75% reduction in the Psoriasis Area and Severity Index (PASI)-75 at 12 weeks among patients with moderate-to-severe plaque psoriasis.1

Announced by Accropeutics on May 20, 2025, the Phase 2 trial met its primary and secondary endpoints for all 3 AC-201 doses. The primary endpoint was the PAS-75 at week 12, and secondary endpoints included the PASI-90 at week 12 and the static Physician’s Global Assessment (sPGA) (0 = clear; 1 = almost clear).

“We are excited to see the positive results from the phase II study of AC-201, and we will accelerate its clinical development to benefit patients with psoriasis and other autoimmune diseases,” said Xiaohu Zhang, co-founder and CEO of Accropeutics, in a statement.1

AC-201 binds to the pseudokinase domain of TYK2/JAK1 without affecting the AK2/JAK2 signaling pathway. The inhibitor is being developed to treat immune-mediated inflammatory diseases such as psoriasis and systemic lupus erythematosus. Phase 1 trials have demonstrated AC-201’s safety and tolerability in healthy volunteers from Australia and China.2

In their multicenter, randomized, double-blind, placebo-controlled phase 2 trial, investigators randomized 145 patients in China with moderate to severe plaque psoriasis 1:1:1 to receive placebo or AC-201 25 mg twice a day, 50 mg twice a day, or 100 mg once a day.1

At week 12, the PASI-75 response rates were 31.4% for AC-201 25 mg (P = .012), 74.3% for 50 mg (P < .001), and 59.5% for 100 mg (P < .001), compared with 8.1% for placebo. As for PASI-90, response rates were 20% for AC-201 25 mg (P = .02), 48.6% for 50 mg (P < .001), and 24.3% for 100 mg (P = .007).

The AC-201 50 mg group had the greatest proportion of participants who achieved a sPGA-0/1 (71.4%; P < .001), followed by AC-201 100 mg (59.5%; P < .001), AC-201 25 mg (31.4%; P = .0004), and placebo (5.4%).

AC-201 was well tolerated, with no serious adverse events or adverse events leading to discontinuation. Most treatment-emergent adverse events were mild or moderate in severity, and the most frequent ones included upper respiratory tract infection and hypertriglyceridemia.

References

1. Accropeutics Announces Positive Data from Phase 2 Trial of AC-201, an oral, selective TYK2/JAK1 Inhibitor, for the treatment of Moderate-to-Severe Plaque Psoriasis. PR Newswire. May 20, 2025. https://www.prnewswire.com/news-releases/accropeutics-announces-positive-data-from-phase-2-trial-of-ac-201-an-oral-selective-tyk2jak1-inhibitor-for-the-treatment-of-moderate-to-severe-plaque-psoriasis-302461241.html. Accessed May 21, 2025.

2. 201 - pipeline - pipeline - accro bioscience(suzhou)limited. AC. Accessed May 21, 2025. https://www.accropeutics.com/pipeline/ac201.