A Phase 2 study evaluating safety, tolerability, and efficacy of SNA-120 ointment when administered topically with calcipotriene ointment for the treatment of pruritus and psoriasis.

All subjects are required to meet eligibility requirements and undergo a calcipotriene run-in period (Part A) prior to qualifying and randomizing into the study to receive either SNA-120 or Placebo ointment in combination with calcipotriene ointment (Part B). Combination therapy (SNA-120 ointment + calcipotriene ointment or Placebo ointment + calcipotriene ointment) is to continue over an 8 week period to evaluate safety, tolerability and the efficacy of treatment on both persistent pruritus and the visible signs and symptoms of psoriasis.

Inclusion Criteria:

• Written informed consent
• Stable psoriasis for at least 6 months prior to screening
• Chronic pruritus of the psoriasis plaques at least 6 weeks prior to screening
• At least moderate baseline overall itch associated with psoriatic plaques
• Willing and able to undergo a 4-week run-in with calcipotriene ointment dosing and remain on this stable regimen throughout the study
• Mild or moderate psoriasis at screening and baseline
• Subject's plaques are amenable to treatment with a topical medication
• Willing and able to discontinue all other topical products to treat psoriasis and/or itch, including topical steroids
• Willing and able to avoid prolonged exposure of the designated treatment plaques to ultraviolet (UV) radiation (natural and artificial) for the duration of the study
• Women of childbearing potential must have a negative pregnancy test and must agree to use highly effective methods of contraception during the study
• Men who engage in sexual activity that can result in fathering children must agree to use highly effective forms of contraception during the study

Exclusion Criteria:

• Underlying conditions other than psoriasis that, in the opinion of the investigator, currently cause or influence pruritus of the overall skin
• Current or past history of hypercalcemia, Vitamin D toxicity, severe renal insufficiency, or severe hepatic disorders
• Thyroid abnormalities that, in the opinion of the investigator, are clinically relevant and may affect assessments
• Current diagnosis of guttate, erythrodermic, exfoliative, or pustular psoriasis
• Subjects with a clinical diagnosis of bacterial infection of the skin
• Subjects who have previously failed treatment with or failed to tolerate treatment with calcipotriene
• Known hypersensitivity to SNA-120 (pegcantratinib), calcipotriene, the study treatment excipients, and /or polyethylene glycol (PEG), or a history of drug or other allergy that, in the opinion of the investigator, contraindicates participation
• Currently enrolled in an investigational drug or device study or has used an investigational drug or an investigational device treatment within 30 days or 5 half-lives of investigational drug (whichever is longer) of baseline
• Women who are pregnant or lactating, or are planning to become pregnant during the study
• Subjects previously participating in any SNA-120 (and/or CT327 or pegcantratinib) clinical studies