Open Label, Long-term Study Evaluating Safety and Efficacy of Subcutaneous Amlitelimab in Participants Aged 12 Years and Older With Moderate to Severe Atopic Dermatitis

This is a single group, 1-arm, long-term safety study for treatment of participants with moderate to severe atopic dermatitis (AD). The purpose of this study is to characterize the long-term safety and efficacy of amlitelimab in treated participants with age ≥12 years old with moderate to severe AD. The study duration per participant will be up to 284 weeks, including: * A screening period of up to 2 to 4 weeks * An open label treatment period of up to 268 weeks (approximately 5 years) * A post-treatment safety follow-up period of at least 20 weeks after the last dose administration (last IMP administration at Week 264) The planned number of visits will be 35 visits.

Inclusion Criteria: * Participant must be at least 12 years of age inclusive, at the time of signing the informed consent. * Participants must have AD as defined by the American Academy of Dermatology Consensus Criteria for 1 year or longer at baseline. * Participant must have documented history (within 6 months prior to screening visit), of inadequate response (including inadequate efficacy or medical inadvisability) to topical treatments and/or inadequate response to systemic therapies (within 12 months prior to screening visit). * Eczema Area Severity Index (EASI) of 16 or higher at baseline visit/Visit 2. * Validated Investigator Global Assessment scale for atopic dermatitis (vIGA-AD) of 3 or 4 at baseline visit/Visit 2. * AD involvement of 10% or more of body surface area (BSA) at baseline visit/Visit 2. * Weekly average of daily Peak Pruritus-Numerical Rating Scale (PP-NRS) of ≥ 4 at baseline visit/Visit 2. * Able and willing to comply with requested study visits and procedures. * Body weight must be greater than or equal to 25 kg. * Contraceptive use by men and women should be consistent with local regulations regarding the methods of contraception for those participating in clinical studies. Female participants must not be pregnant or breastfeeding. Exclusion Criteria: * Skin co-morbidity that would adversely affect the ability to undertake AD assessments as per investigator's judgement * Known history of or suspected significant current immunosuppression, including history of invasive opportunistic or helminthic infections despite infection resolution or otherwise recurrent infections of abnormal frequency or prolonged duration. * Any malignancies or history of malignancies prior to baseline (except for non-melanoma skin cancer that has been excised and completely cured for more than 5 years prior to baseline). * History of solid organ or stem cell transplant. * Any pre-planned major elective surgery known about at baseline that in the opinion of the investigator would necessitate that IMP be permanently discontinued or require more than three doses to be missed. * Severe concomitant illness that would in the Investigator's opinion inhibit the participant's participation in the study. * Any medical or psychiatric condition which, in the opinion of the Investigator may present an unreasonable risk to the study participants as a result of his/her participation in this clinical study, may make participant's participation unreliable, or may interfere with study assessments. * Any active or chronic infection including helminthic infection requiring systemic treatment within 4 weeks prior to baseline (1 week in the event of superficial skin infections); and any infection which as per Investigator's opinion precludes the participant's participation in the study. * Treatment with live (attenuated) vaccines within 12 weeks prior to baseline; failure to complete non-live immunizations required by local regulation (eg, vaccination for COVID-19) at least 14 days prior to baseline. * Having received any of the specified therapy within the specified timeframe(s) prior to the baseline visit. * Positive for human immunodeficiency virus (HIV), hepatitis B or hepatitis C at the screening visit. * Participants with active tuberculosis (TB), latent TB, a history of incompletely treated TB, suspected extrapulmonary TB infection, non-TB mycobacterial infection, or who are at high risk of contracting TB (such as close contact with individuals with active or latent TB) or received Bacillus Calmette-Guérin (BCG)-vaccination within 12 weeks prior to Screening. * In the Investigator's opinion, any clinically significant laboratory results from the clinical chemistry, hematology, coagulation, or urinalysis tests at the screening visit. * In the Investigator's opinion, any significant abnormality on 12-lead electrocardiogram (ECG) at the screening visit that could be suggestive of an unstable or underlying cardio-vascular condition that could preclude the participant's participation in the study. * History of hypersensitivity or allergy to any of the excipients or IMP or other allergy that, in the opinion of the Investigator, contraindicates participation in the study. The above information is not intended to contain all considerations relevant to a participant's potential participation in a clinical trial.