Safety and Pharmacokinetic Study of ATI-50002 in Subjects With Alopecia Universalis (AU) and Alopecia Totalis (AT)

Inclusion Criteria: * Able to comprehend and willing to sign an Informed Consent Form (ICF). * Male or non-pregnant, non-nursing female ≥18 years old at the time of informed consent. * Have a clinical diagnosis of stable, clinically typical, AU or AT. * Have a duration of the current episode of AU or AT for a minimum of 6 months and a maximum of seven years. * Be willing and able to follow all study instructions and to attend all study visits. Exclusion Criteria: * Females who are nursing, pregnant, or planning to become pregnant for the duration of the study including 30 days after the last application of study medication. * Patchy alopecia areata, diffuse alopecia areata or a history of an atypical pattern of Alopecia Areata (AA) (e.g., ophiasis, sisaihpo). * Active skin disease on the scalp (such as psoriasis or seborrheic dermatitis) or a history of skin disease on the scalp that in the opinion of the investigator would interfere with the study assessments of efficacy or safety. * Active scalp trauma or other condition affecting the scalp that, in the investigator's opinion, may affect the course of AU or AT or interfere with the study conduct or evaluations. * The presence of a permanent or difficult to remove hairpiece or wig that will, in the opinion of the investigator, interfere with study assessments if not removed at each visit.