Study to Evaluate PF-04965842 in Patients With Moderate to Severe Psoriasis

• Drug: PF-04965842
  
  Subjects will receive 200 mg PF 04965842 twice daily for 4 weeks
  Other Name: JAK1 inhibitor
• Drug: PF-04965842
  
  Subjects will receive 400 mg PF 04965842 daily for 4 weeks
  Other Name: JAK1 inhibitor
• Drug: PF-04965842
  
  Subjects will receive 200 mg PF 04965842 daily for 4 weeks
  Other Name: JAK1 inhibitor
• Other: Placebo
  
  Subjects will receive placebo for 4 weeks

• Experimental: Cohort 1
  
  200mg of PF-04965842 twice daily
  Intervention: Drug: PF-04965842
• Experimental: Cohort 2
  
  400mg of PF-04965842 once daily
  Intervention: Drug: PF-04965842
• Experimental: Cohort 3
  
  200mg of PF-04965842 once daily
  Intervention: Drug: PF-04965842
• Placebo Comparator: Cohort 4
  
  Placebo comparator daily
  Intervention: Other: Placebo

Inclusion Criteria:

1. Have a diagnosis of plaque psoriasis for at least 6 months prior to first study dose.
2. Have plaque type psoriasis covering at least 15% of total BSA at Day 1 (at the time of the first study dose).
3. Have a PASI score of 12 or greater at Day 1 (at the time of the first study dose).
4. Be a candidate for phototherapy or systemic treatment of psoriasis (either naïve or history of previous treatment).

Exclusion Criteria:

1. Currently have non plaque forms of psoriasis, eg, erythrodermic, guttate, or pustular psoriasis.
2. 3. Have current drug induced psoriasis, eg, a new onset of psoriasis or an exacerbation of psoriasis from beta blockers, calcium channel blockers, antimalarial drugs or lithium.
3. Have received any of the following treatment regimens specified in the timeframes outlined below:

Within 9 months of first dose of study drug:

? Ustekinumab (Stelara).

Within 12 weeks of first dose of study drug:

? Any experimental therapy for psoriasis or rheumatoid arthritis.

Within 4 8 weeks of first dose of study drug:

• Biologic therapies for psoriasis have discontinuation periods determined from approximately 5x half life of the respective biologic:
• 4 weeks: etanercept (Enbrel).
• 8 weeks: infliximab (Remicade), adalimumab (Humira).

Within 4 weeks of first dose of study drug:

• Systemic treatments other than biologics that could affect psoriasis (eg, oral or injectable corticosteroids, retinoids, methotrexate, cyclosporine, fumaric acid derivatives, sulfasalazine, hydroxycarbamide (hydroxyurea), azathioprine).
• Phototherapy and psoralen plus ultraviolet A therapy (PUVA).
• Other - intramuscular gold, immunization with any live virus vaccination (eg, FluMist), herbal medications.

Within 2 weeks of first dose of study drug:

• Topical treatments that could affect psoriasis (eg, corticosteroids, tars, keratolytics, anthralin, vitamin D analogs, and retinoids).
• Phototherapy with ultraviolet B (UVB) (narrowband or broadband).