- Males and females 18 years of age and older.
- Clinical diagnosis of psoriasis for at least 6 months as determined by subject interview of his/her medical history and confirmation of diagnosis through physical examination by Investigator.
- Stable plaque psoriasis for at least 2 months before Screening and at Baseline (Week 0) as determined by subject interview of his/her medical history.
- Moderate to severe psoriasis defined by ≥ 10 percent Body Surface Area (BSA) involvement at the Baseline (Week 0) visit.
- PASI score of ≥ 12 at the Baseline (Week 0) visit.
- Subject is a candidate for systemic therapy or phototherapy and has active psoriasis despite prior treatment with topical agents.
- Women are eligible to participate in the study if they meet one of the following criteria:
- Women of childbearing potential must undergo monthly pregnancy testing during the study and agree to use one of the following methods of contraception throughout the duration of the study:
i. Oral contraceptives;
ii. Transdermal contraceptives
iii. Injectable or implantable methods
iv. Intrauterine devices
v. Barrier methods (for example but not limited to a diaphragm with spermicide, condom with spermicide); or
vi. Vasectomized partner
Subjects using oral or parental forms of contraceptives must have been using those methods of birth control for at least three months prior to the study baseline visit.
- Women who are postmenopausal (for at least one year), sterile, or hysterectomized;
- Women who have undergone tubal ligation will be required to undergo monthly pregnancy testing.
- Women who agree to be sexually abstinent, defined as total abstinence from sexual intercourse, is considered an adequate form of contraception. (Agreement to comply with sexual abstinence must be recorded in the source document.)
8. Subject is judged to be in good general health as determined by the Principal Investigator based upon the results of medical history, laboratory profile, physical examination, and 12-lead electrocardiogram (ECG) performed at screening.
9. Able and willing to give written informed consent and to comply with requirements of this study protocol.