Sponsor decision. Not related to safety concern.

This is a multinational, multicenter, double-blind, placebo-controlled, parallel-group Phase 2, 4-arm study in adult participants with moderate to severe AD who are inadequately controlled with topical therapies or for whom such topical therapies are inadvisable and who are candidates for systemic therapy.

Participants will be randomized to receive SAR444656 dose 1, dose 2, dose 3 or matching placebo.

Participants who meet inclusion/exclusion criteria will be stratified for randomization by severity of AD (moderate [baseline EASI score <22] versus severe [baseline EASI score ≥22]).

The total duration of study is approximately 24 weeks, including 1 to 4 weeks for screening, 16 weeks for double-blind study treatment and 4 weeks for follow-up.

Inclusion Criteria:

• Participants with atopic dermatitis as defined by the American Academy of Dermatology Consensus Criteria for at least 1 year before the baseline visit.
• EASI ≥12 at screening and at baseline visit
• vIGA score ≥3 (on the 0 to 4 IGA scale, in which 3 is moderate and 4 is severe) at screening and baseline visit.
• AD involvement ≥10% of BSA at screening and baseline visit
• Baseline PP-NRS ≥4
• Participants must have documented history within 6 months prior to baseline visit, of either inadequate response or inadvisability to topical medications
• Participants must have applied daily topical emollient (moisturizer) for at least the 7 consecutive days immediately before the baseline visit. Participants should continue using daily moisturizers during the study.
• Participants must be willing and able to complete the electronic diary for the duration of the study as required by the study protocol.
• Contraceptive use by men and women should be consistent with local regulations regarding the methods of contraception for those participating in clinical studies.

Exclusion Criteria:

• Presence of other skin conditions that may interfere with study assessments such as psoriasis, tinea corporis, lupus erythematosus
• Any active or chronic infection requiring systemic treatment within 4 weeks prior to baseline
• Known history of, or suspected, significant current immunosuppression, including history of invasive opportunistic or helminth infections despite infection resolution or otherwise recurrent infections of abnormal frequency or prolonged duration.
• History of solid organ or stem cell transplant.
• Participants with history of splenectomy.
• Participants with history of any malignancy or lymphoproliferative disease, except if the participant has been free from disease for ≥5 years. Successfully treated non-metastatic cutaneous squamous cell carcinoma, basal cell carcinoma, or localized carcinoma in situ of the cervix are allowed.
• Family history of sudden death or long QT syndrome.
• History of congenital or drug-induced long QT syndrome.
• Congestive heart failure (NYHA Class 2-4), greater than Class 1 angina pectoris, acute coronary syndrome within prior 6 months, known structural heart disease.
• History of any major cardiovascular events (eg, myocardial infarction, unstable angina pectoris, coronary revascularization, stroke, or transient ischemic attack) at any time prior to screening.
• History of ventricular fibrillation, ventricular tachycardia, Torsades de Pointes, atrial fibrillation, syncope not explained by non-cardiac etiology.
• Uncontrolled hypertension defined as consistent systolic blood pressure ≥150 mm Hg or consistent diastolic blood pressure ≥90 mm Hg despite antihypertensive medication.
• Participants had major surgery within 4 weeks prior to the screening or have planned any elective major surgery during the study.
• Having received any of protocol-specified prohibited therapy (Topical or systemic) within the specified timeframe prior to the baseline visit.

The above information is not intended to contain all considerations relevant to a participant's potential participation in a clinical trial.

Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org