Safety, Pharmacokinetics and Efficacy of ARQ-151 Cream in Adults With Mild to Moderate Chronic Plaque Psoriasis

Inclusion Criteria:

Adult male and female participants aged ≥18 years.
In Cohort 1, participants must have at least 25 cm^2 of chronic plaque psoriasis (excluding the face, scalp, intertriginous areas, palms and soles).
In Cohort 2, participants must have 0.5% to 5.0% of total BSA of chronic plaque psoriasis and at least one target plaque, of at least 9 cm^2 in size with a TPSS ≥4 (excluding the face, scalp, intertriginous areas, palms and soles).
Women of childbearing potential must have a negative urine pregnancy test at Screening and agree to use birth control throughout the trial.
In good health as judged by the Investigator, based on medical history, physical examination, 12-lead electrocardiogram (ECG), serum chemistry labs, hematology values, and urinalysis.
Participants agree not to have prolonged sun exposure during the course of the study. Tanning bed use is not allowed.
Participants are competent to sign and give informed consent and considered reliable and capable of adhering to the Protocol and visit schedule.

Exclusion Criteria:

Participants with non-plaque forms of psoriasis (erythrodermic, guttate, pustular or palmo-plantar psoriasis) or with drug-induced psoriasis.
Evidence of skin conditions other than psoriasis that would interfere with evaluation of the effect of the study medication.
Pregnant or lactating women or women planning to become pregnant during the study and / or within 28 days following the last dose of study medication.
Known allergies to excipients in ARQ-151 cream.
Participants who cannot discontinue the use of strong P-450 cytochrome inducers or inhibitors for two weeks prior to the baseline visit and during the study period.
Participants who are unwilling to refrain from using a tanning bed for 2 weeks before and during the study.
Participants who cannot discontinue systemic therapies and/or topical therapies for the treatment of psoriasis.
Participants with a history of chronic alcohol or drug abuse in past 6 months.
History of and/or concurrent condition of serious hypersensitivity (anaphylactic shock or anaphylactoid reaction) to phosphodiesterase type 4 (PDE-4) inhibitors.
Current or a history of cancer within 5 years with the exception of fully excised skin basal cell carcinoma, cutaneous squamous cell carcinoma or carcinoma in situ of the cervix.
Participants with active infection that requires oral or intravenous administration of antibiotics, antifungal or antiviral agents.
Participants who are unable to communicate, read or understand language, or who display another condition which makes them unsuitable for clinical study participation.