Safety, Tolerability and Efficacy of SNA-120 for Treatment of Pruritus and Psoriasis in Subjects Treated With Calcipotriene

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