This is an open-label, Phase 2/Phase 3, long-term extension study for treatment of participants of previous amlitelimab clinical trials in moderate to severe atopic dermatitis. The purpose of this study is to characterize the safety and efficacy of amlitelimab in treated participants with moderate to severe atopic dermatitis (AD) who have previously been enrolled in an amlitelimab clinical trial. All participants will have visits during the treatment period every 4 weeks. Responder participants rolling over from EFC17599 and EFC17600, and responder participants enrolling through screening from DRI17366 will be initiated into drug withdrawal (with no drug administration) at LTS17367 baseline visit to monitor durability of treatment response. If these responder participants relapse during LTS17367, they will have treatment restored. Non-responder participants rolling over from EFC17599 or EFC17600, and non-responder participants enrolling through screening from DRI17366 will have treatment administration from LTS17367 baseline. Participants rolling over from DRI17366, SFY17915 and INT18404 will also have treatment administration from LTS17367 baseline. Remote visits with home dosing are allowed for the purpose of study drug administration, when applicable. In the case of remote visit with home dosing, the participant or a caregiver may administer study drug after appropriate training. Alternatively, if needed, and based on the investigator's judgement, home visits with healthcare professional assistance or on-site study drug administration visits can be performed. Where participants discontinue amlitelimab permanently during LTS17367, safety follow up will be performed for a minimum of 140 days from the last amlitelimab administration.