This study used a single-cohort, 2-treatment arm, parallel-group randomized, double-blind, double-dummy design in adult patients with episodic migraine and chronic migraine, who had to be either naïve or not suitable for or could have failed up to three prophylactic treatments out of: propranolol/metoprolol, amitriptyline, flunarizine. Patients were stratified into groups according to their number of migraine days during the baseline period.

All patients completing the Baseline period and fulfilling baseline eligibility criteria were invited to participate to the Double-blind, double-dummy Treatment Epoch (DBTE, 24 weeks) .

Eligible patients were randomized to one of two treatment arms. DBTE started with a titration phase for topiramate of a maximum of 6 weeks to determine the maximal tolerated dose and aimed to reach the recommended treatment dose of 100 mg according to the German SmPC. After the titration phase, maintenance phase started (18 weeks). Topiramate dose had to be maintained until the end of the DBTE. Erenumab dose at beginning of the DBTE was determined patient individually by the investigator based on the guidance provided in the SmPC and was either 70 mg or 140 mg. Dose escalation from 70 mg to 140 mg in case of insufficient response was considered at anytime during the DBTE.

Dose reduction of topiramate and erenumab was not allowed during DBTE (Week 0 to Week 24). After Week 24 or if the patient discontinued study drug, a one week double-blind taper off phase followed to ensure proper down titration for topiramate. At the end of the DBTE (24 weeks) the final assessment occurred to address the objectives.

A Follow-Up Visit 4 weeks after last study visit (or 8 weeks after last IMP injection for discontinued patients) was required as part of routine safety monitoring. The primary analysis was triggered when all patients had completed their respective last visit of the DBTE.

The End of study occurred when the last patient completed last visit (LPLV).

Key Inclusion Criteria:

1. Documented history of migraine in the 12 months prior to screen
2. at least 4 days per month of migraine symptoms
3. >=80% diary compliance during the Baseline period
4. Patients must be either naïve or not suitable or have failed previous migraine prophylactic treatments

Key Exclusion Criteria:

1. Older than 50 years of age at migraine onset
2. Pregnant or nursing
3. History of cluster or hemiplegic headache
4. History or evidence of major psychiatric disorder
5. Score of 19 or higher on Beck Depression Inventory (BDI)

Novartis is committed to sharing with qualified external researchers, access to patient-level data and supporting clinical documents from eligible studies. These requests are reviewed and approved by an independent review panel on the basis of scientific merit. All data provided is anonymized to respect the privacy of patients who have participated in the trial in line with applicable laws and regulations.

This trial data availability is according to the criteria and process described on www.clinicalstudydatarequest.com