Inclusion Criteria:  Male or nonpregnant, nonlactating female subject aged 18 to 75 years (inclusive) at the time of informed consent. Subjects with a clinical diagnosis of AA defined as having a SALT score ≥ 50 and in which the current episode of hair loss is > 24 weeks (without evidence of spontaneous terminal hair regrowth ≥ 10% within 24 weeks at the time of screening and baseline), but ≤ 8 years (from onset of current episode).  Exclusion Criteria:  Concomitant active systemic diseases (except stable thyroid diseases) that may cause hair loss (eg, lupus erythematosus, systemic sclerosis, celiac disease) that could interfere with the Investigators' ability to evaluate the subject's response to therapy. Subject's cause of hair loss is indeterminable and/or in addition to AA they have concomitant causes of alopecia, such as traction alopecia, cicatricial alopecia, lichen planopilaris, frontal fibrosing alopecia, advanced androgenetic alopecia (ie, Ludwig Type III or Norwood-Hamilton Stage ≥ V), telogen effluvium, trichotillomania, or diffuse AA (alopecia areata incognita). Known or suspected congenital or acquired immunodeficiency state, or condition that would compromise the subject's immune status (eg, history of splenectomy).