This is a Phase 1, randomized, double-blind, vehicle-controlled, SAD / MAD study evaluating three dose levels of PBI-100 topical cream in healthy adult volunteers and/or subjects with psoriasis.

This is a Phase 1, randomized, double-blind, vehicle-controlled, SAD / MAD study. Three dose levels of PBI-100 topical cream will be evaluated in healthy adult volunteers and/or subjects with psoriasis. Dose escalations will follow a satisfactory review by the Safety Review Committee of all available safety, tolerability, and PK data from the current dose level.

Key Inclusion Criteria:

• Is male or female, between 18 and 65 years of age
• Has a body mass index (BMI) between 18.0 and 32.0 kg/m2
• Is in good general health, as determined by the Investigator, without clinically significant medical history, with the exception of psoriasis for those subjects enrolled in the psoriasis groups

Key Exclusion Criteria:

• Has any visible skin disease (other than psoriasis for subjects in Groups 4 and 7) at the application site which, in the opinion of the Investigator, would interfere with the evaluation of the test site reaction