This prospective multicentre observational study aims to evaluate the long-term effectiveness, safety, tolerability, and treatment persistence of atogepant for migraine prevention in routine clinical practice. Adult patients with migraine initiating atogepant across 15 tertiary Headache Units in Spain are followed for 12 months. Clinical outcomes, including monthly headache days, monthly migraine days, medication overuse, adverse events, treatment discontinuation, and patient-reported outcomes in a subset of participants, are assessed at baseline and after 3, 6, and 12 months. The study also characterizes different response trajectories, including sustained, delayed, and transient responses, in a real-world population with high disease burden and multiple prior preventive treatment failures.

Preventive migraine therapies targeting the calcitonin gene-related peptide (CGRP) pathway have transformed clinical practice, particularly monoclonal antibodies and, more recently, gepants. Atogepant, an oral CGRP receptor antagonist, has demonstrated efficacy and safety in randomized controlled trials and extensions across episodic, chronic, and treatment-refractory migraine populations. However, these studies are based on highly selected cohorts with limited external validity. In routine clinical practice, patients present with high disease burden, multiple preventive treatment failures, prior exposure to CGRP-targeted therapies, medication overuse, and psychiatric comorbidities, all of which may influence outcomes. Although short- and mid-term real-world data support clinically meaningful benefit within 3-6 months, evidence beyond this period remains limited, particularly regarding long-term effectiveness, tolerability, and treatment persistence, as well as sustained, delayed, or transient response trajectories.

This prospective multicentre observational study was conducted within the GEMA (GEpants in MigrAine-Atogepant) Project across 15 tertiary Headache Units in Spain. Adults with migraine initiating atogepant in routine clinical practice were consecutively enrolled between June 2024 and March 2025 and followed for 12 months. Data were collected at baseline and at 3, 6, and 12 months using standardized REDCap case report forms through structured interviews. Variables included sociodemographic and clinical characteristics, migraine phenotype, disease duration, prior preventive treatment failures, concomitant preventive therapies, monthly headache days (MHD), monthly migraine days (MMD), analgesic overuse, adverse events, and treatment discontinuation. Definitions were based on ICHD-3 criteria. In a subset, patient-reported outcomes were assessed using validated instruments: Headache Impact Test (HIT-6), Hospital Anxiety and Depression Scale (HADS), and Insomnia Severity Index (ISI). Analyses were performed using both all-available-observation and complete-case approaches, without imputation of missing outcome data.

Inclusion Criteria:

• Adults aged ≥18 years.
• Diagnosis of migraine with or without aura established by a headache specialist according to the International Classification of Headache Disorders, 3rd edition (ICHD-3), including both chronic and episodic migraine.
• History of migraine of at least 1 year duration.
• Stable preventive migraine treatment (if any) for at least the previous 3 months.
• Normal neurological examination.
• Fulfilment of national health system reimbursement criteria for atogepant treatment.

Exclusion Criteria:

• Cognitive impairment or any other condition that, in the investigator's opinion, may prevent the patient from reliably distinguishing prodromal symptoms.
• Presence of other active primary or secondary headache disorders, except medication overuse headache or infrequent tension-type headache.

Adult patients with migraine, according to ICHD-3 criteria, initiating preventive treatment with atogepant in routine clinical practice were included in this prospective, multicentre, open-label observational study. No masking was applied. Patients were recruited from headache units and neurology departments across Spain:

• Hospital Universitario de La Princesa
• Hospital Universitario de Fuenlabrada
• Fundación Jiménez Díaz-UTE
• Hospital de Torrejón
• Hospital Virgen del Puerto
• Hospital Clínico San Carlos
• Hospital Universitario 12 de Octubre
• Hospital Clínico Universitario de Valladolid (IBIoVALL)
• Hospital Universitario La Paz
• Hospital Clínico Universitario Lozano Blesa
• Hospital Universitario de Getafe
• Hospital Ruber Internacional Treatment initiation with atogepant for migraine prevention was determined by the treating neurologist according to clinical practice guidelines and standard of care.

Individual participant data (IPD) will not be shared with other researchers. This decision is based on data protection and confidentiality requirements in accordance with applicable European and national regulations (including GDPR). Given that this is a multicentre observational study conducted in routine clinical practice, access to IPD is restricted to the study investigators for the purposes of the predefined analyses.

Any potential secondary use of the dataset would only be considered in fully anonymized form and subject to prior ethical approval and compliance with applicable data protection legislation.