This is a longitudinal, observational non-interventional study (NIS) designed to characterize the patient population who receives dupilumab for eosinophilic esophagitis (EoE) treatment in a real-world setting in Germany with respect to their medical history, socio-demographic and disease characteristics, comorbidities (including type 2 inflammatory and atopic conditions), concomitant therapies and prior EoE treatments. Furthermore, this NIS aims to describe the long-term effectiveness of dupilumab for the treatment of EoE as assessed by the treating physician and reported by the patient, and its effect on health-related quality of life (HRQoL) during an individual observational period of two years. In addition, data on real-world use patterns and long-term safety data of dupilumab treatment for EoE will be collected.

The study duration for each participant is planned to be 2 years. Total study duration is approximately 4 years.

Inclusion Criteria:

• Patients diagnosed with EoE who are inadequately controlled by, are intolerant to, or who are not candidates for conventional medicinal therapy
• Patients for whom the treating physician has decided to initiate new treatment with dupilumab for EoE according to EU-SmPC independently from entry in study or for whom treatment with dupilumab for EoE according to EU-SmPC has been started within the last 7 days. The decision to initiate dupilumab treatment is made by the treating physician and the patient according to the patients' medical need and to the standard of best medical practice. This decision is made independently and before inclusion in this NIS.
• ≥ 12 years of age at baseline visit
• ≥ 40 kg bodyweight
• Voluntary study participation and signed written informed consent by patient and parent(s)/guardian(s), if applicable

Exclusion Criteria:

• Patients who have a contraindication to dupilumab according to the current EU-SmPC.
• Patients who have been treated with dupilumab for more than 7 days
• Any acute or chronic condition that, in the treating physician's opinion, would limit the patients' ability to complete questionnaires or to participate in this study or impact the interpretation of the results.
• Participation in an ongoing interventional or observational study that might, in the treating physician's opinion, influence the assessments for the current study (parallel inclusion in another Sanofi-independent registry might be possible if the patient gives consent)

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

Patients suffering from EoE, ≥ 12 years of age with at least 40 kg bodyweight who are planned to be initiated with dupilumab for the treatment of EoE according to the prescribing information, i.e., the current Summary of Product Characteristics approved in the European Union (EU-SmPC).

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