The goal of this clinical trial is to learn if eptinezumab can reduce headache frequency and headache-related disability in adults with idiopathic intracranial hypertension (IIH) and chronic headache. It will also evaluate the safety and tolerability of eptinezumab in this patient population.

The main questions it aims to answer are:

• Does eptinezumab reduce the number of monthly moderate-to-severe headache days compared with placebo?
• Does eptinezumab improve headache-related disability and patient-reported outcomes?
• What adverse events occur during treatment with eptinezumab?

Researchers will compare eptinezumab to placebo to determine whether eptinezumab is effective in the prevention of chronic headache in patients with IIH.

Participants will:

• Receive eptinezumab or placebo according to random assignment.
• Attend scheduled study visits and clinical assessments.
• Complete headache diaries and questionnaires during the study period.
• Undergo study-related examinations and collection of biological samples, including blood samples.

Inclusion Criteria:

• Female, aged 18 to 55 years
• Diagnosis of idiopathic intracranial hypertension (IIH) or IIH without papilledema
• Chronic headache associated with IIH
• At least 15 headache days per monthduring the screening period
• At least 8 migraine-like headache days per month during the screening period
• Use of effective contraception througout the trial period and for at least 5 months after last administration of study drug

Exclusion Criteria:

• Non-compliance with headache diary completion during screening, defined as less than 80% of the days reported
• Contraindications to receiving eptinezumab according to the Summary of Product Characteristics
• Previous or current treatment with anti-CGRP monoclonal antibodies within 5 half-lives
• Previous insufficient or non-effective treatment with eptinezumab
• Pregnancy, breastfeeding, or planning pregnancy during the sudy period

A decision regarding sharing of individual participant data has not yet been made. Any future sharing of de-identified data will be subject to applicable data protection regulations, ethical approvals, and institutional policies.