The Alopecia Areata Investigator’s Global Assessment (AA‐IGA™) Scale: A Measure for Evaluating Clinically Meaningful Success in Clinical Trials

BACKGROUND: Content valid and clinically meaningful instruments are required to evaluate outcomes of therapeutic interventions in alopecia areata (AA). OBJECTIVE: To develop an investigator global assessment (IGA) to interpret treatment response in AA treatment studies. METHODS: Qualitative interviews were conducted in the US with expert dermatologists and AA patients who had experienced >/=50% scalp hair loss. Thematic data analysis identified critical outcomes and evaluated the content validity of the new IGA. RESULTS: Expert clinicians (n=10) judged AA treatment success by the amount of scalp hair growth (median 80% scalp hair). Adult (n=25) and adolescent (n=5) patients participated. Scalp hair loss was the most bothersome AA sign/symptom to most patients. Perceived treatment success -- short of 100% scalp hair -- was the presence of ~70-90% scalp hair (median 80%). Using additional clinician and patient insights, the AA-IGA was developed as an ordinal, static measure comprising five severity categories of the Severity of Alopecia Tool (SALT) 0-100% scores. Nearly all queried clinicians and patients in this study agreed that for patients with >/= 50% scalp hair loss, successful treatment would be hair regrowth resulting in