Paired Psoriasis Lesion, Comparative, Study to Evaluate MOL4239 in Psoriasis

Inclusion Criteria: * Adults, males or females, 18 to 72 years of age (both inclusive.) * Mild to moderate plaque psoriasis with lesions that in total are no more than 9.9% BSA and with a baseline Psoriasis Severity Score (PSS) of 6 or more. * Identification of bilaterally symmetrical or approximately equivalent target lesions of at least 2.5 x 2.5 cm (\~6 cm2) on the trunk, arms or legs to mid calf with a Psoriasis Severity Score (PSS) of 6 or greater. * Willing to avoid tanning devices or exposure of the treated skin to the sun. * Willing to not use cosmetics, including lotions, creams, and moisturizers on the treated lesions. * Use of Eucerin® is allowed on all non-test site areas. * Willing to forgo systemic and other topical treatments for psoriasis during the course of the study. * Willing to avoid bathing or swimming for two hours after study drug treatment. * Negative urine pregnancy test at Screening and baseline for women of childbearing potential (WOCP). * Sexually active WOCP participating in the study must agree to use a medically acceptable method of contraception while on study. * Must have recovered from the effects of any surgery, other than minor office surgical procedures, and a minimum of 3 months must have elapsed from the day of surgery to the day of screening. Exclusion Criteria: * Presence of significant abnormalities of liver or renal functions. * Presence of any clinically significant lab abnormalities at screening. * Any significant uncontrolled medical disease. * Use of the anti-tumor necrosis factor (TNF) biologic agents 4 months prior to randomization or use of Stelara 6 months prior to randomization. * Use, within one month prior to baseline or during the study, of: 1) systemic immunosuppressive drugs (e.g., tacrolimus), or 2) oral meds (e.g. methotrexate, retinoids, etc.). * Use within one month prior to baseline or during the study of: 1) Systemic corticosteroids, 2) Systemic antibiotics, 3) other systemic antipsoriatic treatment, 4) oral psoralen with ultraviolet A (PUVA) therapy, or 5) ultraviolet B (UVB) therapy. * Use within two weeks prior to baseline or during the study of: 1) topical anti-psoriatic drugs, 2) topical corticosteroids, 3) other topical retinoids, or 4) topical immunosuppressive agents. * Current diagnosis of unstable forms of psoriasis in the treatment area, including guttate, erythrodermic, exfoliative or pustular psoriasis. * Other inflammatory skin disease in the treatment area that may confound the evaluation of the psoriasis vulgaris. * Females who are pregnant, breast feeding, or planning a pregnancy.