ME3183, a novel oral phosphodiesterase 4 (PDE4) inhibitor, has demonstrated significant efficacy in treating moderate to severe plaque psoriasis in a phase 2 clinical trial. The study showed that specific dosing regimens, particularly 7.5 mg twice daily and 15 mg once daily, produced rapid and sustained therapeutic effects over 16 weeks with an acceptable safety profile.
Study Design and Patient Population
The randomized, double-blind, placebo-controlled, parallel-group study was conducted from March 28, 2022, to May 31, 2022, across 27 study sites in the United States and Canada. The trial included a 4-week screening period, 16-week treatment period, and 4-week follow-up phase.
A total of 132 male and female patients aged 18 to 75 years participated, with mean ages ranging from 45.3 to 47.3 years across treatment groups. All participants presented with psoriatic plaques covering ≥10% of their body surface area, PASI scores between 12 and 40, and a static Physician's Global Assessment (sPGA) of ≥3.
Patients were randomly assigned to receive ME3183 at doses of 5 mg twice daily (n=26), 10 mg once daily (n=26), 7.5 mg twice daily (n=26), 15 mg once daily (n=27), or placebo (n=27).
Primary Efficacy Results
The primary endpoint was achieving ≥75% reduction in baseline PASI scores at week 16. The 7.5 mg twice daily cohort demonstrated the most robust response, with over 61% of patients reaching the primary endpoint—a result that was statistically significant versus placebo. This group also achieved the highest mean percentage change from baseline PASI at -85.8%.
Comparative PASI75 response rates across treatment groups showed 58.3% in the 5 mg twice daily group, 32% in the 10 mg once daily group, and 52% in the 15 mg once daily group. In contrast, only 14.8% of placebo-treated patients achieved the same reduction.
Secondary Endpoint Analysis
PASI50 response rates ranged from 52% to 75% across all ME3183 treatment groups. The 7.5 mg twice daily cohort again demonstrated superior efficacy with the highest proportion of PASI90 responses at 53.8%, compared to 20-28% in other ME3183 groups and 7.4% in the placebo group.
Complete skin clearance (PASI100) was achieved by 4.2%, 20.0%, 26.9%, and 16.0% of patients in the 5 mg, 10 mg, 7.5 mg, and 15 mg ME3183 groups, respectively. No placebo-treated patients achieved PASI100.
Over 28% of ME3183-treated patients experienced a 2-point reduction on the sPGA scale, with many achieving clear or almost clear skin (score of 0 or 1). Dermatology Life Quality Index (DLQI) scores showed significant improvements across all ME3183 groups, with reductions ranging from 58.8% to 93.3%. These positive changes were not observed in the placebo group.
Quality of Life and Symptom Relief
Itch numerical rating scale (NRS) scores demonstrated meaningful improvements across treatment groups. The 5 mg cohort showed a -4.7 change, the 10 mg group a -3.9 change, and both the 7.5 mg and 15 mg cohorts achieved -5.3 reductions in itch scores.
Safety Profile
The most frequently reported adverse events among ME3183-treated patients included diarrhea (16.0%-38.5%), nausea (7.7%-30.8%), and headache (7.7%-42.3%). The 7.5 mg and 15 mg ME3183 groups experienced the highest proportion of adverse events, though most were characterized as mild to moderate in severity.
Treatment discontinuation due to adverse events occurred in 13 patients overall, with the highest incidence in the 7.5 mg twice daily cohort (5 patients, 19.2%).
Clinical Context and Future Directions
With 4 million cases of psoriasis globally, there remains an unmet need for additional oral psoriasis medications that combine strong efficacy with acceptable safety profiles, according to the study authors. These phase 2 results build upon positive findings from an initial phase 1 study conducted in healthy adults.
The researchers indicate that larger trials with more diverse patient populations will be necessary to further explore ME3183's therapeutic potential and establish optimal dosing strategies for plaque psoriasis treatment.
