First-in-Human Trial to Assess REGN20423 in Healthy Adult Participants and Adult Participants With Atopic Dermatitis

This study will test a study medicine called REGN20423 to see how effective it is in healthy participants (in Part A) and participants with atopic dermatitis (eczema) (in Part B). REGN20423 is a study medicine that is only used in clinical studies. REGN20423 has not previously been studied in humans. The study is looking at: * What side effects REGN20423 might cause * How much REGN20423 is in the blood at different times * How well REGN20423 works in adults with atopic dermatitis * Whether the body makes antibodies against REGN20423 * How the body changes after having REGN20423, which can help researchers understand why REGN20423 works better in some people than others * What the best dose of REGN20423 is

NCT Number	NCT07527923
Lead Sponsor	Regeneron Pharmaceuticals
Conditions	Healthy Volunteer, Atopic Dermatitis
Enrollment	144 participants
Start Date	2026-05-22
Primary Completion	2028-06-23 (estimated)
Study Completion	2028-06-23 (estimated)
Updated on ClinicalTrials.gov	2026-06-25