Study of Safety and Efficacy of Topical GSK2981278 Ointment in Plaque Psoriasis

Inclusion Criteria: * 18 years of age and above, at the time of signing the informed consent. * Subjects with stable plaque psoriasis for \>= 6 months, as confirmed by the subject. * Up to three plaque area(s) sufficient for six test fields. The target lesion(s) should be on the trunk, upper extremities or thighs (excluding hands and skin folds); psoriatic lesion(s) on the knees or elbows are not to be used as a target lesion. It is recommended, but not required, that all selected plaques are symmetrical in location, size and clinical characteristics. * Plaques to be treated should have a comparable thickness of the Echo Lucent Band (ELB) (as a surrogate for the psoriatic infiltrate thickness) of at least 200 micrometers on Day 1. * Male: Male subjects with female partners of child bearing potential must comply with the following contraception requirements from the time of first dose of study medication until after the last dose of study medication. 1. Vasectomy with documentation of azoospermia. 2. Male condom. These allowed methods of contraception are only effective when used consistently, correctly and in accordance with the product label. The investigator is responsible for ensuring that subjects understand how to properly use these methods of contraception. * Female of non-reproductive potential (FNRP): A FNRP is eligible to participate in this study if she meets at least one of the following conditions: 1. Females with one of the following procedures documented and no plans to utilize assisted reproductive techniques (e.g., in vitro fertilization or donor embryo transfer): Bilateral tubal ligation or salpingectomy; Hysteroscopic tubal occlusion procedure with follow-up confirmation of bilateral tubal occlusion; Hysterectomy; Bilateral Oophorectomy (surgical menopause) 2. Post-menopausal women (including all women over 60 years of age, see below), Post-Menopause criteria: Females 60 years of age or older; A practical definition accepts menopause after 1 year without menses with an appropriate clinical profile, e.g., age appropriate, \>45 years, in the absence of hormone replacement therapy (HRT) or medical suppression of the menstrual cycle (e.g., leuprolide treatment) \[In questionable cases for women \< 60 years of age, a blood sample with simultaneous follicle stimulating hormone and estradiol falling into the central laboratory's post-menopausal reference range is confirmatory (these levels need to be adjusted for specific laboratories/assays)\]; Females under 60 years of age, who are on HRT and wish to continue, and whose menopausal status is in doubt, are required to use a highly effective method to avoid pregnancy, as outlined in the protocol. Otherwise, they must discontinue HRT to allow confirmation of post-menopausal status prior to study enrolment. For most forms of HRT, at least 2 to 4 weeks will elapse between the cessation of therapy and the blood draw; this interval depends on the type and dosage of HRT. Following confirmation of their post-menopausal status, they can resume use of HRT during the study without use of a highly effective method to avoid pregnancy * Capable of giving signed informed consent, which includes compliance with the pre-specified requirements and restrictions. Exclusion Criteria: * Alanine aminotransferase (ALT) \>2xUpper Limit of Normal (ULN) and bilirubin \>1.5x ULN (isolated bilirubin \>1.5xULN is acceptable if bilirubin is fractionated and direct bilirubin \<35%). * Current or chronic history of liver disease, or known hepatic or biliary abnormalities (with the exception of Gilbert's syndrome or asymptomatic gallstones). * Corrected QT (QTc) interval \> 450 milliseconds (msec) or QTc \> 480 msec in subjects with Bundle Branch Block. The QTc is the QT interval corrected for heart rate according to Bazett's formula (QTcB), and/or machine-read. The QTc should be based on single QTc values of ECG obtained over a brief recording period. * Any condition that, in the judgement of the investigator, would put the subject at unacceptable risk for the participation in the trial. * Current evidence of another ongoing or any acute cutaneous infection, history of repeated or chronic significant skin infections (unless irrelevant in the opinion of the investigator, i.e. onychomycosis, labial herpes or other minor diagnosis). * Clinically-relevant skin disease, other skin pathologies, or a history of skin cancer, that may, in the opinion of the investigator, contraindicate participation or interfere with test field evaluations. * History of malignancy within 5 years prior to dosing, except adequately treated noninvasive cancer of the skin (basal or squamous cell). * Psoriasis other than plaque variants. * Use of prohibited concomitant medications or products within the defined washout periods before the Day 1 visit and during the trial. * History of sensitivity to any of the study medications, or components thereof or a history of drug or other allergy that, in the opinion of the investigator or Medical Monitor, contraindicates their participation. * Contraindications according to summary of product characteristics of the active positive control. * Symptoms of a clinically significant illness that may, in the opinion of the investigator, influence the outcome of the trial in the 4 weeks before baseline visit and during the trial. * Presence of hepatitis B surface antigen (HBsAg), positive hepatitis C antibody test result at screening or within 3 months prior to first dose of study treatment. * A positive pre-study drug/alcohol screen. * A positive test for human immunodeficiency virus (HIV) antibody. * The subject has participated in a clinical trial and has received an investigational product within the following time period prior to the first dosing day in the current study: 30 days, 5 half-lives or twice the duration of the biological effect of the investigational product (whichever is longer). * Prolonged exposure to natural or artificial sources of ultraviolet (UV) radiation within 2 weeks prior to the Day 1 visit or intention to have such exposure during the study, thought by the investigator likely to modify the subject's psoriasis. * In the opinion of the investigator or physician performing the initial examination the subject should not participate in the clinical trial, e.g. due to probable noncompliance or inability to understand the trial and give adequately informed consent. * Close affiliation with the investigator (e.g. a close relative) or persons working at Bioskin GmbH or subject is an employee of sponsor. * Subject is institutionalized because of legal or regulatory order.