Restless Legs SyndromePhase 3NCT04161027
RCT for Pregabalin in Restless Legs Syndrome in South Korea
A Phase 3 study testing Pregabalin 75mg in people with Restless Legs Syndrome, run by Seoul National University Hospital at 1 site in South Korea.
Trial summary
This randomized, double-blind, placebo-controlled, multicenter clinical trial is designed to to assess the treatment efficacy and tolerability of pregabalin in patients with idiopathic restless legs syndrome in South Korea. Read more about this study
- Who is it for?
- Ages 19 to 80 years
- Conditions the study is for
- Restless Legs Syndrome
- What is being tested?
- Pregabalin 75mg
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 116 participants
- Where
- 1 siteSouth Korea
- Study dates
- 24 Feb 2020to 4 Apr 2022
- Phase
- Phase 3
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 19 to 80 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- IRLS (international restless legs scale) score ≥ 15
- RLS symptom occurring ≥ 3 times/week and persisting over ≥ 6 months
- Drug-naive patients or those who stop taking RLS drugs for ≥ 1 week before screening
Who cannot join
- Secondary RLS (including iron deficiency anemia, pregnancy, chronic kidney disease [eGFR < 60 mL/min/1.73 m2], peripheral neuropathy, others)
- Serum Ferritin < 10 μg/L or history of oral iron therapy within 3 months or intravenous iron therapy within 1 year
- Severe comorbid medical or psychiatric disorders
- history of pregabalin or gabapentin treatment within 3 months
- High risk of obstructive sleep apnea by STOP-BANG questionnaire
- Other comorbid sleep disorders or shift workers
- Hypersensitivity to pregabalin
- Galactose intolerance, Lapp lactase deficiency, or glucose-galactose malabsorption
Trial locations and contacts
1 site in 1 country.
About this study
Official title: A Randomized, Double-blind, Placebo-controlled Multicenter Study to Assess Efficacy and Safety of Pregabalin in Willis-Ekbom Disease/Restless Legs Syndrome
This randomized, double-blind, placebo-controlled, multicenter clinical trial is designed to to assess the treatment efficacy and tolerability of pregabalin in patients with idiopathic restless legs syndrome in South Korea.
Read the detailed description
Objectives: To assess the treatment efficacy and tolerability of pregabalin in patients with idiopathic restless legs syndrome (RLS) in South Korea.
Study Design: A randomized, double-blind, placebo-controlled, multicenter clinical trial Study period: total 14 weeks: 2 weeks for placebo run in period and 12 weeks treatment after randomization (titration for 4 weeks and maintenance for 8 weeks).
Subjects: a total number of 100 participants (randomly assigned 1:1 to pregabalin or placebo). The sample number was calculated based on a superiority design, 1-sided, alpha 0.05 with power 80% and drop rate 10%.
Inclusion criteria: adults aged between 19-80 and diagnosed with idiopathic RLS with IRLS score of 15 or more.
Exclusion criteria: Secondary RLS; serum ferritin < 10 μg/L or history of oral iron therapy within 3 months or intravenous iron therapy within 1 year; severe comorbid medical or psychiatric disorders; history of pregabalin or gabapentin treatment within 3 months; other comorbid sleep disorders or shift workers.
Treatment schedule and dose
- Placebo responders, who showed a decrease of IRLS score of 40% or more, are excluded before randomization. Subjects will randomly assigned to receive either pregabalin or placebo with a 1:1 allocation. A starting dose is 75 mg/day for 2 weeks (taken 1-2 hours before habitual bedtime). At the visit of 2 weeks and 4 weeks, a dose can be titrated by 75-150 mg according to the response and tolerability. A dose ranging 75-300 mg per day will be maintained for 8 weeks.
Primary outcome: changes in IRLS score after 12-week treatment. Secondary outcomes: remission rate (decrease in IRLS score of 50% or more), CGI (clinical global impression)-improvement, changes in 10-cm visual analog scale (VAS), RLS-6, PSQI (pittsburgh sleep quality index), ISI (insomnia severity index), Johns Hopkins RLS QoL after 12-week treatment.
Statistical analysis: ANCOVA for changes in IRLS score with a baseline IRLS score as a covariate.
Tolerability: Safety profiles and Liverpool Adverse Event Profile (LAEP) will be assessed.
- Conditions
- Restless Legs Syndrome
- Being tested
- Pregabalin 75mg, Placebos
- Keywords
- Restless legs syndrome; pregabalin; Willis-Ekbom disease
- Medical subject headings
- Restless Legs Syndrome
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Pregabalin 75mgDrug
Pregabalin 75 mg capsule
PlacebosDrug
Placebo capsule
| Study group | Role | What they receive |
|---|---|---|
| Pregabalin | Experimental | Not described Receives: Drug: Pregabalin 75mg |
| Placebo | Placebo comparator | Not described Receives: Drug: Placebos |
What is being measured
The primary outcome is the main question the study is designed to answer.
International restless legs scale score
Changes in International restless legs scale (IRLS) score after 12-week treatment. IRLS is used to assess the severity of patient's RLS symptoms. A total score ranges from 0 to 40 and higher scores mean more severe symptoms. Therefore, greater differences in IRLS scores between baseline and post-treatment mean a better outcome.
Measured: Baseline (week 0) and post-treatment (week 12)
Secondary outcomes (7)
Remission rate
A proportion of patients who showed a decrease in IRLS score of 50% or more after treatment. Higher scores mean a better outcome.
Measured: Baseline (week 0) and post-treatment (week 12)
CGI (clinical global impression)-improvement
The amount of RLS symptom improvement measured by physicians. CGI-improvement is a 7-point scale and rated as 1 (Very much improved), 2 (Much improved), 3 (Minimally improved), 4 (No change), 5 (Minimally worse), 6 (Much worse), and 7 (Very much worse).
Measured: Post-treatment (week 12)
10-cm visual analog scale (VAS)
Changes in 10-cm VAS after 12-week treatment. A VAS score ranges from 0 (no symptoms) to 10 (very severe symptoms).
Measured: Baseline (week 0) and post-treatment (week 12)
Restless legs syndrome (RLS)-6
Changes in RLS-6 scores after 12-week treatment. A RLS-6 consists of 6 questions for RLS symptoms and a total score ranges from 0 (no symptoms) to 60 (very severe symptoms).
Measured: Baseline (week 0) and post-treatment (week 12)
PSQI (pittsburgh sleep quality index)
Changes in PSQI scores after 12-week treatment. A total PSQI score ranges from 0 to 21, and higher scores indicate worse sleep quality.
Measured: Baseline (week 0) and post-treatment (week 12)
ISI (insomnia severity index)
Changes in ISI scores after 12-week treatment. A total ISI score range from 0 to 28 and categories: 0-7 (No clinically significant insomnia), 8-14 (Subthreshold insomnia), 15-21 (Moderate insomnia), and 22-28 (Severe insomnia)
Measured: Baseline (week 0) and post-treatment (week 12)
Johns Hopkins Restless legs syndrome quality of life
Changes in Johns Hopkins Restless legs syndrome quality of life scores after 12-week treatment. A total score ranges from 0 to 100 and lower scores indicate worse quality of life.
Measured: Baseline (week 0) and post-treatment (week 12)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted13 Nov 2019
- Study start24 Feb 2020
- Primary completion4 Apr 2022
- Study completion4 Apr 2022
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Restless Legs SyndromeStudies of the same condition, open and under way.
- More trials run by Seoul National University HospitalThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 3
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- A randomized, double-blind, placebo-controlled, multicenter clinical trial. Study subjects will be recruited from 4 medical centers in South Korea.
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 116 participants (actual)
Sponsor and investigators
- Lead sponsor
- Seoul National University Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Ki-Young Jung, Seoul National University Hospital
- Investigators
- Ki-Young Jung, MD, PhD, Principal investigator, Seoul National University Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04161027
- Sponsor's protocol ID
- 1903-121-1021
- Status last verified
- Apr 2023
- First submitted
- 6 Nov 2019
- Last updated
- 24 Apr 2023
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Sunwoo JS, Cho YW, Shin WC, Byun JI, Shin JW, Jung KY. Efficacy and Safety of Pregabalin for Restless Legs Syndrome in Korean Adults: A Randomized, Double-Blind, Placebo-Controlled Trial. J Clin Neurol. 2025 Jul;21(4):325-331. doi: 10.3988/jcn.2025.0092.
PubMed 40635537
Study at a glance
From the registry record, last updated by the sponsor on 24 Apr 2023. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Randomized, Double-blind, Placebo-controlled Multicenter Study to Assess Efficacy and Safety of Pregabalin in Willis-Ekbom Disease/Restless Legs Syndrome
- ClinicalTrials.gov ID
- NCT04161027
- Acronym / sponsor ID
- 1903-121-1021
- Conditions
- Restless Legs Syndrome
- Keywords
- Restless legs syndrome; pregabalin; Willis-Ekbom disease
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 116 participants (actual)
- Lead sponsor
- Seoul National University HospitalUniversity, hospital or other
- Study start
- 24 Feb 2020 (actual)
- Primary completion
- 4 Apr 2022 (actual)
- Study completion
- 4 Apr 2022 (actual)
- First posted
- 13 Nov 2019 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This randomized, double-blind, placebo-controlled, multicenter clinical trial is designed to to assess the treatment efficacy and tolerability of pregabalin in patients with idiopathic restless legs syndrome in South Korea.
Detailed description
Objectives: To assess the treatment efficacy and tolerability of pregabalin in patients with idiopathic restless legs syndrome (RLS) in South Korea.
Study Design: A randomized, double-blind, placebo-controlled, multicenter clinical trial Study period: total 14 weeks: 2 weeks for placebo run in period and 12 weeks treatment after randomization (titration for 4 weeks and maintenance for 8 weeks).
Subjects: a total number of 100 participants (randomly assigned 1:1 to pregabalin or placebo). The sample number was calculated based on a superiority design, 1-sided, alpha 0.05 with power 80% and drop rate 10%.
Inclusion criteria: adults aged between 19-80 and diagnosed with idiopathic RLS with IRLS score of 15 or more.
Exclusion criteria: Secondary RLS; serum ferritin < 10 μg/L or history of oral iron therapy within 3 months or intravenous iron therapy within 1 year; severe comorbid medical or psychiatric disorders; history of pregabalin or gabapentin treatment within 3 months; other comorbid sleep disorders or shift workers.
Treatment schedule and dose
- Placebo responders, who showed a decrease of IRLS score of 40% or more, are excluded before randomization. Subjects will randomly assigned to receive either pregabalin or placebo with a 1:1 allocation. A starting dose is 75 mg/day for 2 weeks (taken 1-2 hours before habitual bedtime). At the visit of 2 weeks and 4 weeks, a dose can be titrated by 75-150 mg according to the response and tolerability. A dose ranging 75-300 mg per day will be maintained for 8 weeks.
Primary outcome: changes in IRLS score after 12-week treatment. Secondary outcomes: remission rate (decrease in IRLS score of 50% or more), CGI (clinical global impression)-improvement, changes in 10-cm visual analog scale (VAS), RLS-6, PSQI (pittsburgh sleep quality index), ISI (insomnia severity index), Johns Hopkins RLS QoL after 12-week treatment.
Statistical analysis: ANCOVA for changes in IRLS score with a baseline IRLS score as a covariate.
Tolerability: Safety profiles and Liverpool Adverse Event Profile (LAEP) will be assessed.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- A randomized, double-blind, placebo-controlled, multicenter clinical trial. Study subjects will be recruited from 4 medical centers in South Korea.
| Arm | Type | Receives |
|---|---|---|
| Pregabalin | Experimental | Drug: Pregabalin 75mg |
| Placebo | Placebo comparator | Drug: Placebos |
Who may qualify
- Ages
- 19 to 80 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- IRLS (international restless legs scale) score ≥ 15
- RLS symptom occurring ≥ 3 times/week and persisting over ≥ 6 months
- Drug-naive patients or those who stop taking RLS drugs for ≥ 1 week before screening
Key exclusion criteria (8 listed)
- Secondary RLS (including iron deficiency anemia, pregnancy, chronic kidney disease [eGFR < 60 mL/min/1.73 m2], peripheral neuropathy, others)
- Serum Ferritin < 10 μg/L or history of oral iron therapy within 3 months or intravenous iron therapy within 1 year
- Severe comorbid medical or psychiatric disorders
- history of pregabalin or gabapentin treatment within 3 months
- High risk of obstructive sleep apnea by STOP-BANG questionnaire
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Pregabalin 75mgPregabalin 75 mg capsule | Drug | Pregabalin |
| PlacebosPlacebo capsule | Drug | Placebo |
Primary outcome
International restless legs scale score
Time frame: Baseline (week 0) and post-treatment (week 12)
Changes in International restless legs scale (IRLS) score after 12-week treatment. IRLS is used to assess the severity of patient's RLS symptoms. A total score ranges from 0 to 40 and higher scores mean more severe symptoms. Therefore, greater differences in IRLS scores between baseline and post-treatment mean a better outcome.
7 secondary outcomes
Remission rate
Time frame: Baseline (week 0) and post-treatment (week 12)
CGI (clinical global impression)-improvement
Time frame: Post-treatment (week 12)
10-cm visual analog scale (VAS)
Time frame: Baseline (week 0) and post-treatment (week 12)
Restless legs syndrome (RLS)-6
Time frame: Baseline (week 0) and post-treatment (week 12)
PSQI (pittsburgh sleep quality index)
Time frame: Baseline (week 0) and post-treatment (week 12)
ISI (insomnia severity index)
Time frame: Baseline (week 0) and post-treatment (week 12)
Johns Hopkins Restless legs syndrome quality of life
Time frame: Baseline (week 0) and post-treatment (week 12)
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 24 Apr 2023.
- Derived from this study: PubMed 40635537Sunwoo JS, Cho YW, Shin WC, Byun JI, Shin JW, Jung KY. Efficacy and Safety of Pregabalin for Restless Legs Syndrome in Korean Adults: A Randomized, Double-Blind, Placebo-Controlled Trial. J Clin Neurol. 2025 Jul;21(4):325-331. doi: 10.3988/jcn.2025.0092.
- Individual participant dataSharing planned: No
Related trials for Restless Legs Syndrome
RecruitingObservational study
Lemborexant vs Clonidine vs Sedatives to Treat Insomnia in Chronic Pain Patients
Chronic Insomnia, Chronic Pain
Not yet recruiting
Neuromodulation to Overcome Severe Restless Legs Syndrome
Restless Leg Syndrome (RLS), Spinal Cord Stimulation (SCS)
Not yet recruitingPhase 2
Tolerability and Efficacy of CBD Extract for RLS Treatment
Restless Leg Syndrome
Recruiting
Functional Connectivity of the Interoceptive Network in RLS
Restless Legs Syndrome
Not yet recruitingPhase 2
Intravenous Iron in the Management of Drug-resistant Restless Legs syndromeI
Restless Legs Syndrome (RLS)
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Ki-Young Jung, MD, PhD principal investigator
Seoul National University Hospital
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing Pregabalin 75mg in people with Restless Legs Syndrome, run by Seoul National University Hospital at 1 site in South Korea.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 24 Apr 2023. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in South Korea. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
International restless legs scale score (time frame: Baseline (week 0) and post-treatment (week 12)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT04161027, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 24 Apr 2023.