GSK2894512 Vehicle-Controlled Study for Adult Plaque Psoriasis

• Age >=18 years at the time of signing the informed consent.
• Clinical diagnosis of chronic stable plaque psoriasis. Diagnosis and chronicity to be confirmed and documented by an experienced dermatologist.
• Body surface area involvement >=2%.
• A PGA score of >=2.
• One target plaque located on the trunk or extremities that is at least 9 centimeter (cm)\^2 in size with a target plaque severity score (TPSS) >=5 and an induration sub score >=2. Primary target plaque should not be located on the knees, elbows, feet, ankle, hands, intertriginous areas, face, or scalp.)

• Male or female. A female is eligible to participate if she is not pregnant, not breastfeeding, and at least one of the following conditions applies:

  • Not a woman of childbearing potential (WOCBP), OR
  • Is a WOCBP who agrees to follow the specified contraceptive guidance throughout the study, including screening, during the treatment period, and for at least 1 week after the last exposure to study treatment.
• Capable of giving signed informed consent

Exclusion Criteria:

• Psoriasis other than plaque variant.
• Any sign of infection of any of the psoriatic lesions.

• Concurrent conditions and history of other diseases:

  • Immunocompromised (examples: lymphoma, acquired immunodeficiency syndrome) or have a history of malignant disease within 5 years before the Baseline visit.
  • Chronic or acute infection requiring treatment with systemic antibiotics, antivirals, antiparasitics, antiprotozoals, or antifungals within 4 weeks before the Baseline visit.
  • Active acute bacterial, fungal, or viral (examples: herpes simplex, herpes zoster, chicken pox) skin infection within 1 week before the Baseline visit
  • Significant dermatologic or inflammatory condition other than plaque psoriasis that, in the investigator's opinion, would make it difficult to interpret data or assessments during the study.
• A history or ongoing serious illness or medical, physical, or psychiatric condition(s) that, in the investigator's opinion, may interfere with the subject's completion of the study.
• Known hypersensitivity to GSK2894512 or excipients of the study treatments, or a history of drug or other allergy that, in the opinion of the investigator, contraindicates participation.
• Alanine transferase (ALT) >2 times upper limit of normal (ULN).
• Bilirubin >1.5 times ULN (isolated bilirubin >1.5 times ULN is acceptable if bilirubin is fractionated and direct bilirubin \<35%).
• Current unstable liver or biliary disease per investigator assessment defined by the presence of ascites, encephalopathy, coagulopathy, hypoalbuminemia, esophageal or gastric varices, persistent jaundice, or cirrhosis.
• Stable chronic liver disease (including Gilbert's syndrome, asymptomatic gallstones, and chronic stable hepatitis B or C, examples: presence of hepatitis B surface antigen [HBsAg] or positive hepatitis C antibody test result at screening or within 3 months prior to starting study treatment) is acceptable if the subject otherwise meets entry criteria.
• QT interval corrected for heart rate according to Fridericia's formula QTcF >450 milliseconds (msec) or QTcF >480 msec in subjects with bundle branch block.
• Ultraviolet (UV) light therapy or prolonged exposure to natural or artificial sources of UV radiation (examples: phototherapy, tanning beds/booths, or therapeutic sunbathing) within 4 weeks prior to the Baseline visit and/or intention to have such exposure during the study, which could potentially impact the subject's psoriasis (as determined by the investigator).

• Used any of the following treatments within the indicated period before the Baseline visit:

  • Minimum of 5 half-lives for biologic agents -12 months: rituximab or efalizumab; 8 months: ustekinumab; 5 months: secukinumab; 12 weeks: golimumab; 10 weeks: ixekizumab; 8 weeks: infliximab, adalimumab, or alefacept; 4 weeks: etanercept (list is not exclusive, contact medical monitor for questions).
  • 4 weeks -systemic treatments: cyclosporin, interferon, methotrexate, apremilast, tofacitinib, mycophenolate, thioguanine, hydroxyurea, sirolimus, azathioprine, other systemic immunosuppressive or immunomodulating agents, fumaric acid derivatives, vitamin D3 and analogs, retinoids (examples: acitretin, isotretinoin), psoralens, corticosteroids, or adrenocorticotropic hormone analogs.
  • 2 weeks -immunizations; drugs known to possibly worsen psoriasis, such as beta-blockers (example, propranolol), lithium, iodides, angiotensin-converting enzyme inhibitors, and indomethacin, unless on a stable dose for >12 weeks.
  • 2 weeks -topical treatments: corticosteroids, immunomodulators, anthralin (dithranol), Vitamin D derivatives (examples: calcipotriene, calcipotriol), retinoids (example, tazarotene), or coal tar (used on the body).
• Participated in a clinical study and received an investigational product within the following time period prior to the Baseline visit: 4 weeks, 5 half-lives, or twice the duration of the biological effect of the investigational product (whichever is longer).
• Participated in a previous study using GSK2894512 or WBI-1001.