A Phase 3B, open-label, single-arm study of the efficacy and safety of apremilast, in subjects with plaque psoriasis that is not adequately controlled by topical therapy

Subjects must satisfy the following criteria to be enrolled in the study: 1. Subject is ≥ 20 years of age at the time of signing the informed consent form (ICF) with plaque psoriasis. 2. Subject has understood and voluntarily signed an informed consent document prior to any study related assessments/procedures being conducted. 3. Subject is able to adhere to the study visit schedule and other protocol requirements. 4. Subject has chronic plaque psoriasis based on a diagnosis for at least 6 months prior to Baseline. 5. Subject has psoriasis with sPGA = 2 or 3 at screening and baseline. 6. Subject is currently treated for psoriasis with topical therapies only for at least 4 weeks prior to Baseline. 7. Subject has inadequate response to current topical therapy as per Investigator’s discretion. 8. Subject is naïve to all biologic therapies for psoriasis vulgaris. 9. Subject must be in general good health (except for psoriasis) as judged by the Investigator, based on medical history, physical examination, and clinical laboratories. (NOTE: The definition of good health means a subject does not have uncontrolled significant co-morbid conditions). 10. Subjects that are females of childbearing potential (FCBP) must have a negative pregnancy test at Screening and Baseline. While on investigational product and for at least 28 days after taking the last dose of investigational product, FCBP who engage in activity in which conception is possible must use one of the approved contraceptive options described below: Option 1: Any one of the following highly effective methods: hormonal contraception (oral, injection, implant, transdermal patch, vaginal ring); intrauterine device; tubal ligation; or partner’s vasectomy; OR Option 2: Male or female condom (latex condom or nonlatex condom NOT made out of natural [animal] membrane [for example, polyurethane]) PLUS one additional barrier method: (a) diaphragm with spermicide; (b) cervical cap with spermicide; or (c) contraceptive sponge with spermicide.

The presence of any of the following will exclude a subject from enrollment: 1. Subject has any condition, including other inflammatory diseases or dermatologic conditions, which confounds the ability to interpret data from the study, including other types of psoriasis (ie, pustular, inverse, erythrodermic, or guttate), other than plaque psoriasis. 2. Subject has psoriatic arthritis that requires systemic therapy. 3. Subject has history of drug-induced psoriasis. 4. Subject has had prior treatment with biologic therapies for psoriasis. 5. Subject has used phototherapy or conventional systemic therapy for psoriasis within 8 weeks prior to baseline and during the study (including but not limited to cyclosporine, corticosteroids, methotrexate, oral retinoids, mycophenolate, thioguanine, hydroxyurea, sirolimus, sulfasalazine, azathioprine). 6. Subject has worsening of psoriasis indicated by an increase in sPGA of ≥ 1 from Screening to Baseline. 7. Subject cannot avoid excessive sun exposure or use of tanning booths for at least 8 weeks prior to Baseline and during the study. 8. Subject is currently enrolled in any other clinical trial involving an investigational product. 9. Subject has other than psoriasis, any clinically significant (as determined by the Investigator) cardiac, endocrinologic, pulmonary, neurologic, psychiatric, hepatic, renal, hematologic, immunologic disease, or other major disease that is currently uncontrolled. 10. Subject has malignancy or history of malignancy or myeloproliferative or lymphoproliferative disease within the past 3 years, except for treated (ie, cured) basal cell or squamous cell in situ skin carcinomas. 11. Subject has received a live vaccine within 3 months of baseline or plans to do so during study. 12. Subject is pregnant or breastfeeding (lactating) women. 13. Subject has bacterial infections requiring treatment with oral or injectable antibiotics, or significant viral or fungal infections, within 4 weeks of Screening. Any treatment for such infections must have been completed and the infection cured, at least 4 weeks prior to Screening and no new or recurrent infections prior to the Baseline Visit. 14. Subject is hepatitis B surface antigen positive or hepatitis B core antibody positive at screening. 15. Subject is positive for antibodies to hepatitis C at screening. 16. Subject has any condition, including the presence of laboratory abnormalities, which would place the subject at unacceptable risk if he/she were to participate in the study. 17. Subject has prior history of suicide attempt at any time in the subject’s life time prior to signing the informed consent and enrollment, or major psychiatric illness requiring hospitalization within the last 3 years prior to signing the informed consent. 18. Subject has active substance abuse or a history of substance abuse within 6 months prior to signing the informed consent. 19. Subject has prior treatment with apremilast or participation in a clinical study involving apremilast.