A Study of the Efficacy and Safety of Apremilast (CC-10004) in Subjects With Moderate to Severe Plaque Psoriasis of the Scalp

Inclusion Criteria: Subjects must satisfy the following criteria to be enrolled in the study:

• Males or females, ≥ 18 years of age at the time of signing the informed consentdocument

• Be willing and able to adhere to the study visit schedule and other protocolrequirements.

• Have a diagnosis of moderate to severe plaque psoriasis of the scalp at screening andbaseline

• Must be a candidate for phototherapy and/or systemic therapy for either body or scalppsoriasis lesions.

• Have moderate to severe plaque psoriasis at screening and baseline

• Must be in good health (except for psoriasis) as judged by the Investigator, based onmedical history, physical examination, 12-lead electrocardiogram (ECG), clinicallaboratories, and urinalysis

• Must meet laboratory criteria

• Females of childbearing potential (FCBP)* must have a negative pregnancy test atscreening and baseline. While on investigational product (IP) and for at least 28 daysafter taking the last dose of investigational product, FCBP who engage in activity inwhich conception is possible - must use one of the approved contraceptive** optionsdescribed below: Option 1: Any one of the following highly effective methods: hormonal contraception (oral,injection, implant, transdermal patch, vaginal ring); intrauterine device (IUD); tuballigation; or partner's vasectomy; OR Option 2: Male or female condom (latex condom ornonlatex condom NOT made out of natural [animal] membrane [for example, polyurethane]; PLUSone additional barrier method: (a) diaphragm with spermicide; (b) cervical cap withspermicide; or (c) contraceptive sponge with spermicide.

*A female of childbearing potential is a sexually mature female who 1) has not undergone ahysterectomy (the surgical removal of the uterus) or bilateral oophorectomy (the surgicalremoval of both ovaries) or 2) has not been postmenopausal for at least 24 consecutivemonths (that is, has had menses at any time during the preceding 24 consecutive months).

** The female subject's chosen form of contraception must be effective by the time thefemale subject is randomized into the study (for example, hormonal contraception should beinitiated at least 28 days before randomization).

Exclusion Criteria: The presence of any of the following will exclude a subject from enrollment:

• Other than psoriasis, history of any clinically significant uncontrolled disease. Any condition, including the presence of laboratory abnormalities, which would place thesubject at unacceptable risk if he/she were to participate in the study.

• Pregnant or breast feeding

• Hepatitis B surface antigen positive at screening

• Anti-hepatitis C antibody positive at screening

• Active tuberculosis (TB) or a history of incompletely treated TB

• Clinically significant abnormality on 12-lead electrocardiogram (ECG) at screening

• History of positive human immunodeficiency virus (HIV), or have congenital or acquiredimmunodeficiency (eg, common variable immunodeficiency disease)

• Active substance abuse or a history of substance abuse within 6 months prior tosigning the informed consent form.

• Bacterial infections requiring treatment with oral or injectable antibiotics, orsignificant viral or fungal infections, within 4 weeks of signing the informed consentform.

• Malignancy or history of malignancy, except for treated (i.e., cured) basal cell orsquamous cell in situ skin carcinomas or treated (i.e., cured) cervicalintraepithelial neoplasia (CIN) or carcinoma in situ of the cervix with no evidence ofrecurrence within 5 years of signing the informed consent.

• Prior history of suicide attempt at any time in the subject's life time prior tosigning the informed consent and randomization, or major psychiatric illness requiringhospitalization within the last 3 years prior to signing the informed consent.

• Psoriasis flare/rebound within 4 weeks of signing the informed consent form or betweenthe screening and baseline visits.

• Topical therapy within 2 weeks prior to randomization; Conventional systemic therapyfor psoriasis within 4 weeks prior to randomization; Intralesional corticosteroids onthe scalp within 2 weeks prior to randomization; Phototherapy treatment of body orscalp psoriasi lesions within 4 weeks prior to randomization; Biologic therapy between 12 weeks to 24 weeks prior to randomization

• Use of any investigational drug beginning 4 weeks prior to randomization, or 5pharmacokinetic/pharmacodynamic half-lives, if known (whichever is longer)

• Prolonged sun exposure or use of tanning booths or other ultraviolet (UV) lightsources

• Prior treatment with apremilast

• History of allergy or hypersensitivity to any components of the Investigationalproduct.