A Study of R3421 in Patients With Moderate to Severe Chronic Plaque Psoriasis.

A Randomized, Placebo-controlled Dose-ranging Pilot Study to Assess the Effect on Clinical Response, and the Safety and Tolerability of R3421 in Patients With Moderate to Severe Chronic Plaque Psoriasis

This study will investigate the safety, efficacy and pharmacokinetics of R3421 in patients with moderate to severe chronic plaque psoriasis. Patients will be randomized to one of 3 treatment groups to receive once daily oral treatment with a)R3421 20mg, b)R3421 120mg, or c)placebo. The anticipated time on study treatment is <3 months, and the target sample size is <100 individuals.

Inclusion Criteria:

• adult patients, 18-70 years of age;
• medically stable, moderate to severe chronic plaque psoriasis.

Exclusion Criteria:

• any skin condition which may interfere with evaluation of the effect of study medication on plaque lesions;
• confounding or concomitant condition or treatment.