Twin Trial of PDE4 Inhibition With Roflumilast for the Management of Plaque Psoriasis

Inclusion Criteria:

• Participants legally competent to sign and give informed consented and if appropriateassent as required by local laws
• Males and females ages 2 years and older (inclusive)
• Clinical diagnosis of psoriasis vulgaris of at least 6 months duration (3 months forchildren) as determined by the Investigator
• Females of childbearing potential (FOCBP) must have a negative pregnancy test atScreening (Visit 1) and Baseline (Visit 2). In addition, sexually active FOCBP mustagree to use at least one form of highly effective contraception throughout the trial.
• In good health as judged by the Investigator, based on medical history, physicalexamination, serum chemistry labs, hematology values, and urinalysis.
• Subjects considered reliable and capable of adhering to the Protocol and visitschedule, according to the judgment of the Investigator.

Exclusion Criteria:

• Planned excessive exposure of treated area(s) to either natural or artificialsunlight, tanning bed or other LED.
• Females who are pregnant, wishing to become pregnant during the study, or arebreast-feeding.
• Previous treatment with ARQ-151 or its active ingredient
• Subjects with any serious medical condition or laboratory abnormality that wouldprevent study participation or place the subject at significant risk, asdetermined by the Investigator.
• Subjects with a history of chronic alcohol or drug abuse within 6 months ofinitiation of investigational product
• Subjects who are unable to communicate, read or understand the local language, orwho display another condition, which in the Investigator's opinion, makes themunsuitable for clinical study participation