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NCT Number: NCT07822607

Intravenous Iron in the Management of Drug-resistant Restless Legs syndromeI

The pathophysiology of restless legs syndrome (RLS) is not well understood: it is thought to involve intracerebral iron deficiency and dopaminergic dysregulation.

This study aims to evaluate the use of intravenous ferric carboxymaltose in patients with restless legs syndrome (RLS).

This study plans to include individuals with RLS, who will be divided into two groups:

* One group will receive intravenous iron immediately after the baseline polysomnography * The second group will receive intravenous iron 3 months after randomization. In total, participants will be followed for 6 months, during which time they will be required to complete questionnaires regularly, undergo blood draws, and have two polysomnography tests.

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Key information

Conditions

Restless Legs Syndrome (RLS) Dyssomnias Mental Disorders Nervous System Diseases Parasomnias Restless Legs Syndrome Sleep Disorders, Intrinsic Sleep Wake Disorders

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

CHU de Montpellier

Montpellier, France

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age ≥ 18 years;
  • Weight ≥ 50 kg;
  • Drug-resistant RLS;
  • Severe to very severe RLS (IRLSSG-Q score > 20), persistent or recurrent for more than one month;
  • Treatment with dopamine agonists without exceeding the recommended doses (ropinirole ≤ 2 mg/day, pramipexole ≤ 0.54 mg/day, rotigotine ≤ 3 mg/day);
  • Treatment with dopamine agonists and/or α2δ ligands and/or opioids that has been stable for at least 3 months;
  • In cases of sleep apnea syndrome, treatment with continuous positive airway pressure (CPAP);
  • Participants were required to be fluent in spoken and written French, be enrolled in a health insurance plan, agree to the automated processing of anonymized confidential data, and have provided written, informed consent for the study.

Exclusion criteria

  • Iron supplementation (oral or intravenous) within 3 months prior to enrollment and throughout the study period
  • Serum ferritin < 50 µg/L or > 300 µg/L;
  • Transferrin saturation < 20% or > 45%;
  • Hemochromatosis;
  • RLS augmentation syndrome ;
  • Treatment with neuroleptics or antidepressants;
  • Allergy to iron;
  • Severe infectious or inflammatory disease within the past 3 months;
  • RLS associated with chronic kidney disease, pregnancy, or a clinically significant neurological or psychiatric disorder;
  • Severe sleep apnea syndrome (AHI > 30/h) that is untreated, or in cases where treatment is refused or has failed;
  • Known allergy, inflammatory, or immune disorder;
  • History of severe asthma, eczema, or any other atopic allergy;
  • Pregnancy or breastfeeding;
  • Also excluded are patients participating in another research study, those deprived of their liberty by judicial or administrative order, those living in a medical facility, those subject to a legal protection order, or those from whom consent could not be obtained.

Treatment and study plan

Ferric Carboxymaltose Injection [Ferinject]

Drug

administration of 1 g of CMF for 2 hours under medical monitoring

Randomization

Other

Randomization in the arm "Immediate treatment" or "Delayed-onset treatment"

Questionnaire and Physical Exam

Other

Completion of questionnaires and scales: European Quality of Life 5 Dimensions (EQ-5D), Epworth Sleepiness Scale (ESS), Clinical Global Impression (CGI), Patient Global Impression (PGI), Beck Depression Inventory-II (BDI-II), Augmentation Severity Rating Scale (ASRS), International Restless Legs Study Group Severity Rating Scale (IRLSSG-Q), International Restless Legs Syndrome (IRLS), Insomnia Severity Index (ISI)

Lumbar Puncture

Procedure

Lumbar puncture performed according to standard practice

Urine pregnancy test

Procedure

During inclusion visit (Day 0) only for women of childbearing age

Primary outcomes

  1. IRLSSG-Q score

    Time frame: From Day 0 to Week 12

    IRLSSG-Q : International Restless Legs Study Group Severity Rating Scale allows for the quantification of the severity of restless legs syndrome

Secondary outcomes

  1. Periodic Limb Movements during Sleep (PLMS) index

    Time frame: From V1 (Day 0) to V5 (week 24)

    The PLMS Index measures the average number of involuntary leg movements per hour of sleeping during polysomnography. 15 or more per hour: Considered abnormal for adults and may suggest a condition called Periodic Limb Movement Disorder (PLMD) if it disrupts your sleep.

  2. Total sleep time

    Time frame: From day 0 to week 24

    Total sleep time measured in minutes during polysomnography.

  3. Sleep latency

    Time frame: From Day 0 to week 24

    Length of time in minutes it takes to transition from full wakefulness to the lightest stage of sleep after the lights are turned off.

  4. Sleep time at stage 1-2 during polysomnography

    Time frame: From Day 0 to week 24

    Time spent in stage 1-2 sleep measured in hours and minutes during polysomnography

  5. Sleep time at stage 3 during polysomnography

    Time frame: From Day 0 to week 24

    Time spent in stage 3 sleep measured in hours and minutes during polysomnography

  6. Micro-awakenings index (MAI)

    Time frame: From Day 0 to week 24

    The Micro-awakenings index measures the number of brief awakenings that the person does not notice per hour of sleep.

  7. Apnea-hypopnea index (AHI)

    Time frame: From Day 0 to week 24

    The apnea-hypopnea index (AHI) measures the average number of interruptions or reductions in breathing per hour of sleep to assess the severity of sleep apnea.

  8. Average arterial oxygen saturation (SaO2)

    Time frame: From Day 0 to Week 24

    The unit of measurement for SaO2 is the percentage (%).

  9. Oxygen desaturation index (IDO)

    Time frame: From Day 0 to week 24

    The oxygen desaturation index (IDO) measures the number of significant drops in blood oxygen levels per hour of sleep.

  10. Serum ferritin

    Time frame: From Day 0 to week 24

  11. Transferrin saturation coefficient

    Time frame: From Day 0 to Week 24

  12. Epworth Sleepiness Scale (ESS)

    Time frame: From Day 0 to Week 24

    A measure of excessive daytime sleepiness that quantifies the impact of the condition on alertness throughout the day. Eight everyday situations are rated (for example, watching television, riding as a passenger in a car, sitting quietly in a public place). Each situation is scored from 0 to 3 based on the likelihood of falling asleep. Total score 0-24; a score of ≥10 suggests excessive sleepiness

  13. European Quality of Life 5 Dimensions (EQ-5D)

    Time frame: From Day 0 to Week 24

    EQ-5D: this self-administered questionnaire assesses five dimensions (mobility, daily activities, self-care, pain/discomfort, anxiety/depression) as well as overall health status on a visual scale from 0 to 100

  14. Clinical Global Impression (CGI)

    Time frame: From Day 0 to Week 24

    The clinician's overall assessment of the illness, including CGI-S (severity) and CGI-I (change). 7-point scale: CGI-S 1 = normal, 7 = extremely ill; CGI-I 1 = markedly improved, 7 = markedly worsened

  15. Patient Global Impression (PGI)

    Time frame: From Day 0 to Week 24

    Patient's overall perception of the severity of their illness or change; a simple 7-point scale, self-reported. A high score is associated with patients perceiving their symptoms as severe

  16. Beck Depression Inventory-II (BDI-II)

    Time frame: From Day 0 to Week 24

    BDI-II: a self-administered questionnaire consisting of 21 items that assess the severity of depressive symptoms over the past two weeks; score range: 0-63; thresholds: 0-13 (mild), 14-19 (moderate), 20-28 (severe), ≥29 (severe)

  17. Augmentation Severity Rating Scale (ASRS)

    Time frame: From Day 0 to Week 24

    A 7-item self-administered questionnaire used to quantify the severity of the augmentation syndrome in patients treated with dopamine agonists. It assesses the worsening or early onset of RLS symptoms and their impact on sleep and daily activities

  18. Insomnia Severity Index (ISI)

    Time frame: From Day 0 to week 24

    To assess the severity of the patient's insomnia, taking into account both the quantity and quality of sleep, as well as its impact on daily functioning (fatigue, concentration, mood). A 7-item self-report questionnaire scored from 0 to 4, with a total score of 0-28; 0-7 indicates no insomnia, 8-14 mild, 15-21 moderate, and 22-28 severe insomnia

Interested in participating?

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Sponsors and collaborators

Lead sponsor

University Hospital, Montpellier

Other

Registry information

Official study title

Intravenous Iron in the Management of Drug-resistant Restless Legs Syndrome: a Randomized Controlled Delayed-start Trial. IRON-RLS

Acronym: IRON-RLS

Important dates

Study start
2026
Primary completion
2029
Study completion
2030
First posted
Sep 16, 2026
Registry last updated
Sep 16, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

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This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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