Long-term Efficacy of Baricitinib in Adults With Moderate to Severe Atopic Dermatitis Who Were Treatment Responders or Partial Responders: An Extension Study of 2 Randomized Clinical Trials

IMPORTANCE: Baricitinib, an oral selective Janus kinase inhibitor, improved the clinical signs and symptoms of moderate to severe atopic dermatitis in the 16-week, phase 3 monotherapy studies, BREEZE-AD1 and BREEZE-AD2. Long-term efficacy has not yet been examined. OBJECTIVE: To evaluate the long-term (68-week) efficacy of baricitinib in adults with moderate to severe atopic dermatitis who were treatment responders or partial responders in BREEZE-AD1 and BREEZE-AD2. DESIGN, SETTING, AND PARTICIPANTS: Patients completing BREEZE-AD1/BREEZE-AD2 entered the ongoing, multicenter, double-blind, long-term extension study BREEZE-AD3. The study was initiated on March 28, 2018. Data were analyzed on December 13, 2019. INTERVENTIONS: Responders and partial responders (patients achieving validated Investigator Global Assessment for Atopic Dermatitis [vIGA-AD] score of 0 or 1 [0,1], or 2) at BREEZE-AD1/BREEZE-AD2 completion remained on originally assigned treatment for 52 weeks (68 total weeks of continuous therapy). MAIN OUTCOMES AND MEASURES: The primary end point was the proportion of patients achieving a vIGA-AD score of 0,1 at weeks 16, 36, and 52 of BREEZE-AD3. Secondary end points included the proportion of patients achieving 75% or more improvement in the Eczema Area and Severity Index [EASI75] score and 4-point or more improvement in the itch numeric rating scale (NRS), using originating study baseline data. Itch data were collected during the first 16 weeks in BREEZE-AD3. The last originating study visit was the first BREEZE-AD3 visit; therefore, data are presented for continuous weeks of therapy, including the 16-week originating study period. Missing data were imputed by last observation carried forward. Modified intention-to-treat analysis was used. RESULTS: Of the responder/partial responder population, the proportion of patients treated with baricitinib, 4 mg (n = 70) (mean [SD] age, 36.7 [15.5] years; 42 [60%] were men), achieving vIGA-AD (0,1) at week 16 was 45.7% (BREEZE-AD3 baseline) and, at week 68, 47.1%. Improvement of 75% or more in the EASI score was 70.0% at week 16 and 55.7% at week 68. The proportion of patients achieving an itch NRS improvement greater than or equal to 4 points at week 16 was 52.5% and, at week 32, 45.9%. Of the responder/partial responder population, the proportion of patients treated with baricitinib, 2 mg (n = 54) (mean [SD] age, 32.8 [12.7] years; 28 [51.9%] were men), achieving vIGA-AD (0,1) at week 16 was 46.3% and, at week 68, 59.3%. Improvement in the EASI75 score was 74.1% at week 16 and 81.5% at week 68. The proportion of patients achieving an itch NRS improvement greater than or equal to 4 points at week 16 was 44.2% and, at week 32, 39.5%. CONCLUSIONS AND RELEVANCE: In this long-term double-blind extension study of 2 randomized clinical trials, baricitinib, 4 and 2 mg, demonstrated sustained long-term efficacy in patients with moderate to severe atopic dermatitis. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03334435