Efficacy of ferric carboxymaltose (FCM) 500 mg dose for the treatment of Restless Legs Syndrome

IntroductionThere have been four randomized, placebo-controlled, double-blinded studies of intravenous (IV) iron in Restless Legs Syndrome (RLS), all of which delivered a final total dose of 1000 mg of iron. The purpose of this study was to evaluate effects of a lesser total dose (500 mg of iron).MethodsSubjects with idiopathic RLS were enrolled in a randomized, double-blinded, placebo-controlled study. Subjects received either 500 mg ferric carboxymaltose (FCM) or placebo as a single infusion (Phase I). Subjects who were previously on medication were off any RLS medications for at least two weeks prior to baseline assessment. The primary outcome variable was a change-from-baseline at week six on the International RLS Severity Scale (IRLSS) and a subject-completed Visual Analog Scale of Severity (VAS). Phase II of the study involved long-term (30 weeks) follow-up after completing the six week efficacy phase.ResultsAt week six post infusion, FCM, compared to placebo recipients, showed no significantly greater change-from-baseline for both primary outcome measures (IRLSS scale, FCM 500 mg vs. placebo: −8.3 ± 7.5 vs. −4.8 ± 8.7, p = 0.100; VAS, FCM 500 mg vs. placebo: −23.4 ± 24.1 vs. −13.3 ± 23.1, p = 0.077). None of the secondary outcome variables showed a significant difference at week six. Seven (21.9%) of the 32 subjects treated with iron in Phase I remained free from further RLS medications at 30 weeks. No serious adverse effects were found in this study.ConclusionsThis study did not show significant benefit from a single 500 mg FCM treatment for RLS symptoms. The two previous, well-controlled, trials of 1000 mg FCM showed significant treatment benefits which suggested that there may have been a clinically relevant total dose required to achieve a clinical response.     

Patient characteristics predicting responses to intravenous ferric carboxymaltose treatment of restless legs syndrome

BackgroundSignificant benefit of intravenous ferric carboxymaltose (FCM) treatment for restless legs syndrome (RLS) has been well-established. However, no clinical indicators predicting treatment response of RLS have been established. This study aimed to determine factors predicting outcome of clinical FCM treatment of RLS patients.MethodsData were retrospectively reviewed from all patients who received FCM treatment for RLS from April 2016 to April 2019. These data included: detailed history, international RLS scale score (IRLS), questionnaires, comorbidity, and previous RLS medication use. Morning fasting serum iron, ferritin, and total iron-binding capacity were measured before and at four weeks after treatment. RLS patients with possible secondary RLS were identified by reviewing the medical histories. This included patients with iron deficiency anemia, lumbosacral radiculopathy, and gastrectomy. Primary RLS included those with no indication of secondary medical factors contributing to RLS. Treatment response was assessed using the IRLS and clinical ratings at four weeks after FCM administration. Patients with a greater than 40% decrease in IRLS were classified as responders.ResultsThe study comprised 164 patients with IRLS and clinical ratings obtained before and at four weeks after intravenous (IV) iron. Treatment responses differed considerably between diagnostic groups of RLS. Percentage responding was: 64.7% (66 of 102) for patients with primary RLS, 90.9% (10 of 11) with gastrectomy, 91.3% (21 of 23) with iron deficiency anemia and 39.3% (11 of 28) with lumbosacral radiculopathy. When responders were compared to non-responders in primary RLS patients, responders had significantly lower serum iron (80.5 ± 26.7 vs. 95.8 ± 30.5 μg/dL, p = 0.022) and percentage transferrin saturation (%TSAT) (25.4 ± 9.6 vs. 30.5 ± 10.5%, p = 0.026) in females, but not males. Logistic regression controlling for major subject variables showed that %TSAT significantly predicted response. (odds ratio [OR]: 0.955, confidence interval: 0.913–0.998, p = 0.040).ConclusionIntravenous FCM in moderate to severe RLS patients is beneficial as a first-line or add-on treatment, particularly for patients with compromised peripheral iron state. Overall, lower %TSAT predicted better chance of responding to the IV iron treatment especially for females.     

Relation of the International Restless Legs Syndrome Study Group rating scale with the Clinical Global Impression severity scale,the restless legs syndrome 6-item questionnaire,and the restless legs syndrome-quality of life questionnaire

BackgroundThe SP790 study (ClinicalTrials.gov, NCT00136045) showed benefits of rotigotine over placebo in improving symptom severity of restless legs syndrome (RLS), also known as Willis-Ekbom disease, on the International Restless Legs Syndrome Study Group rating scale (IRLS), Clinical Global Impression item 1 (CGI-1), RLS 6-item questionnaire (RLS-6), and the RLS-quality of life questionnaire (RLS-QoL) in patients with moderate to severe idiopathic RLS. To provide clinical context for the IRLS and to guide the choice of assessment scales for RLS studies, our post hoc analysis of SP790 data evaluated associations between the IRLS and the CGI-1, IRLS and RLS-6, and the IRLS and RLS-QoL.MethodsScale associations were analyzed at baseline and at the end of maintenance (EoM) using data from the safety set (rotigotine and placebo groups combined [n = 458]). Changes from baseline to EoM in IRLS score vs comparator scale scores also were analyzed.ResultsThere was a trend towards increasing IRLS severity category with increasing CGI-1, RLS-6, and RLS-QoL score. Pearson product moment correlation coefficients showed correlations between IRLS and comparator scale scores at baseline and EoM as well as correlations for change from baseline to EoM.ConclusionCorrelations between the IRLS and comparator scales were substantial. These data indicate that the IRLS is clinically meaningful. The IRLS and CGI-1 are generally sufficient to evaluate the overall severity and impact of RLS symptoms in clinical trials.     

Clinical efficacy of ferric carboxymaltose treatment in patients with restless legs syndrome

ObjectiveThere have been three randomized, placebo-controlled, double-blind studies of intravenous iron in restless legs syndrome (RLS), with differing outcomes. The one positive study used ferric carboxymaltose (FCM) at a total dose of 1000 mg. The purpose of this study was to replicate and extend the findings from the prior FCM study.MethodsNon-anemic, idiopathic RLS patients were enrolled in a randomized, double-blinded, placebo-controlled study and received either 1000 mg FCM or placebo as a single infusion (phase I). Subjects were off any RLS medications for at least two weeks prior to baseline assessment. The primary outcome variable was change from baseline at week 6 on the International Restless Legs Syndrome Severity (IRLSS) scale and a subject-completed, visual analog scale (VAS) of severity. Phase II of the study involved long-term (30 weeks) follow-up after completion of the six-week efficacy phase.ResultsAt week 6 postinfusion, FCM compared to placebo recipients showed significantly greater change from baseline for both primary outcome measures (IRLSS scale, −11.9 ± 8.04 vs −7.88 ± 5.89, p = 0.03; VAS, −40.6 ± 22.7 vs −21.3 ± 20.0, p = 0.001). None of the secondary outcome variables showed a significant difference at week 6. After six weeks of treatment, the FCM group had 19 (59.4%) responders, of which 12 had IRLSS scores <10 (“remitters”). Twelve (37.5%) of the 32 subjects treated with iron in phase I remained free of further RLS medications at 30 weeks. There were no serious adverse events observed in this study.ConclusionTwo studies now support the value of FCM treatment both in the short term (six weeks) and long term (30 weeks) for improving RLS symptoms.     

Difference in background factors between responders to gabapentin enacarbil treatment and responders to placebo: pooled analyses of two randomized,double-blind,placebo-controlled studies in Japanese patients with restless legs syndrome

ObjectiveRestless legs syndrome (RLS) is a sensorimotor disorder that is characterized by uncomfortable and unpleasant sensations mainly in the legs. Two placebo-controlled studies (Phase II/III and post-marketing) in Japanese patients with RLS failed to demonstrate the efficacy of gabapentin enacarbil (GE) 600 mg in the change from baseline in International Restless Legs Syndrome Rating Scale (IRLS) score at the end of the treatment period. The high response to placebo is thought to be a possible reason why the post-marketing study failed. The objectives of these post hoc analyses were to determine potential predictive factors associated with improvement in IRLS score with GE treatment and to identify subgroups with higher placebo responses.MethodsWe combined data from the two Japanese studies and analyzed change from baseline in IRLS score in the pooled population and subgroups defined by several patient characteristics. Moreover, we calculated the variable importance of each factor and performed predictive enrichment analysis to identify an enrichable subpopulation with greater improvement by GE treatment.ResultsThe post hoc analyses suggested that higher baseline IRLS score (≥21) and higher body mass index (≥25 kg/m²) were associated with higher placebo responses. On the other hand, positive family history of RLS, prior use of dopaminergic receptor agonists, and higher baseline ferritin level (≥50 ng/mL) were associated with higher responses to GE.ConclusionsOur results suggest that patients with typical idiopathic RLS characteristics, including positive family history and no low ferritin level, would be expected to derive the greatest benefits from GE treatment.     

Ropinirole improves depressive symptoms and restless legs syndrome severity in RLS patients: a multicentre, randomized, placebo-controlled study

Comorbid depressive symptoms in restless legs syndrome (RLS) remain a treatment challenge, as some antidepressants aggravate RLS symptoms. Preliminary data in depressive patients suggest antidepressant properties of ropinirole. The present study investigates the effects of ropinirole immediate release (IR) on depressive symptoms and RLS severity. A multicenter, placebo-controlled, double-blind randomized (3:1) study was performed including patients with moderate to severe idiopathic RLS and at least mild depressive symptoms. Ropinirole IR (in flexible doses up to 4 mg/day) or placebo was given for 12 weeks including an uptitration phase of 7 weeks. Visits were scheduled at screening, baseline, and weeks 1, 4, and 12 with additional telephone contacts for dosing decisions. The modified intent to treat population comprised 231 patients (171 ropinirole, 60 placebo). The MADRS (Montgomery–Asberg Depression Rating Scale) scores decreased from baseline to week 12 from 18.8 to 8.7 in the ropinirole group and from 18.4 to 12.1 in the placebo group (primary endpoint, adjusted mean treatment difference −3.6 (95% CI: −5.6 to −1.6, significance in favor of ropinirole: P < 0.001). The superiority of ropinirole compared to placebo was confirmed by the Hamilton Scale for Depression and Beck Depression Inventory-II scores. RLS severity scores (IRLS) decreased by 14.7 (ropinirole) and by 9.9 (placebo, P < 0.001) points. Three out of four subdomains of the Medical Outcomes Study Sleep Scale improved significantly. The findings indicate that mild to moderate depressive symptoms should not be treated before sufficient therapy for RLS. Antidepressant medication can be necessary if depression symptoms still persist even if RLS symptoms are ameliorated.     

Noninvasive Vagus Nerve Stimulation: A New Therapeutic Approach for Pharmacoresistant Restless Legs Syndrome

AimsThis work aimed to study the effect of noninvasive vagus nerve stimulation on severe restless legs syndrome (RLS) resistant to pharmacotherapy.Materials and MethodsPatients with severe pharmacoresistant RLS were recruited from a tertiary care sleep center. Intervention was one-hour weekly sessions of transauricular vagus nerve stimulation (tVNS) in the left cymba concha, for eight weeks. The primary outcome measure was the score on the International Restless Legs Rating Scale (IRLS); secondary outcome measures were quality of life (Restless Legs Syndrome Quality of Life scale [RLSQOL]), mood disorders using the Hospital Anxiety and Depression scale subscale for depression (HADD) and Hospital Anxiety and Depression scale subscale for anxiety (HADA), and objective sleep latency, sleep duration, efficiency, and leg movement time measured by actigraphy.ResultsFifteen patients, 53% male, aged mean 62.7 ± 12.3 years with severe RLS, reduced quality of life, and symptoms of anxiety and depression, were included. The IRLS improved from baseline to session eight: IRLS 31.9 ± 2.9 vs 24.6 ± 5.9 p = 0.0003. Of these participants, 27% (4/15) had a total response with a decrease below an IRLS score of 20; 40% (6/15) a partial response with an improvement in the IRLS > 5 but an IRLS above 20; and 33% (5/15) were nonresponders. After tVNS, quality of life improved (RLSQOL 49.3 ± 18.1 vs 80.0 ± 19.6 p = 0.0005), as did anxiety (HADA 8.9 ± 5.4 vs 6.2 ± 5.0 p = 0.001) and depression (HADD 5.2 ± 4.5 vs 4.0 ± 4.0 p = 0.01). No significant change was found in actigraphic outcome measures.ConclusionsIn this pilot study, tVNS improved the symptoms of RLS in 66% of participants (10/15) with severe pharmacoresistant RLS, with concomitant improvements in quality of life and mood. Randomized controlled trials evaluating therapeutic efficacy of tVNS in RLS are needed to confirm these promising findings.     

Treatment of restless legs syndrome/Willis-Ekbom disease with the non-selective ENT1/ENT2 inhibitor dipyridamole: testing the adenosine hypothesis

ObjectivesRecent animal models of restless legs syndrome (RLS) suggest that brain iron deficiency is associated with a hypoadenosinergic state, with downregulation of adenosine A₁ receptors (A1R) in the striatum and cortex. We hypothesized that an increase in extracellular adenosine induced by inhibitors of adenosine transporters, such as the non-selective ENT1/ENT2 inhibitor dipyridamole, would result in an improvement in RLS symptoms.MethodsIn a prospective two-month open-label, non-placebo controlled clinical trial, 15 untreated idiopathic RLS patients began treatment with 100 mg dipyridamole (with uptitration to 400 mg if necessary). Multiple Suggested Immobilization Tests and polysomnography were performed at baseline and at eight weeks. Severity was assessed at four and eight weeks using the IRLS, and the CGI scales. The primary endpoint was therapeutic response (50% improvement in IRLS total score).ResultsThirteen patients completed the study. IRLS score improved from a mean (±S.D.) of 23.4 ± 4.6 at baseline to 10.7 ± 4.5 at eight weeks. Six out of 13 patients were full responders and four were partial responders. The mean (±S.D.) effective dose of dipyridamole at eight weeks was 281.8 ± 57.5 mg/day. Sleep variables also improved, and the mean (±S.D.) periodic leg movement index decreased from 26.7 ± 7.2 to 4.3 ± 1.9. Dipyridamole was generally well tolerated. Main side effects were abdominal cramps, diarrhea, dizziness, and flushing.ConclusionsThese preliminary results suggest that dipyridamole has significant therapeutic effects on both sensory and motor symptoms, as well as sleep. In addition, it provides evidence that hypoadenosinergic mechanisms play a central role in RLS.Classification of evidenceThe study provides class III evidence supporting the therapeutic effects of dipyridamole in RLS.     

Low risk of iron overload or anaphylaxis during treatment of restless legs syndrome with intravenous iron: a consecutive case series in a regular clinical setting

ObjectiveTo evaluate the incidence of iron overload and anaphylaxis following intravenous (IV) iron treatment of restless legs syndrome (RLS).MethodsA total of 58 consecutive RLS patients, meeting clinical requirements for IV iron treatment according to current IRLSSG guidelines were recruited. IV iron treatment consisted of two 500 mg infusions of ferric carboxymaltose (FCM) administered five days apart. During each of the three follow-up visits we obtained blood samples, substantia nigra echogenity index (SNEI) by means of transcranial sonography (TCS), and assessed the severity of RLS symptoms (IRLS scale). “Iron overload risk” was defined as transferrin saturation (TSAT) > 45% on two consecutive follow-up visits. In patients who had a reduction in systemic iron levels following treatment, an additional 500 mg of FCM was administered when feasible. In such cases an additional two follow-up visits were performed.ResultsAmong the total sample, only 2/58 participants met criteria for iron overload risk. They had no evidence of liver damage and did not require additional treatment. Among the 21 patients receiving an additional 500 mg infusion after, only one patient was diagnosed with iron overload risk. Among these three patients, only one was a hemochromatosis gene carrier. No anaphylaxis or other side-effects were reported.ConclusionsIn real-life clinical conditions, the risk of iron overload is low when IV FCM is administered according to the safety limits defined in the current RLS treatment guidelines. However, a close clinical follow-up with periodic blood sampling for iron status, is needed.     

Seasonality of restless legs syndrome: symptom variability in winter and summer times

IntroductionRestless legs syndrome (RLS) is a common sensorimotor neurological disorder, with symptoms that might cause sleep fragmentation leading to excessive daytime sleepiness. A seasonality of RLS symptoms has been suggested; however, to date, no study focused on this aspect. In order to detect a possible seasonality of RLS manifestations, we evaluated RLS symptom severity and excessive daytime sleepiness in winter and summer in RLS patients.MethodsRLS patients who performed two follow-up visits in summer and winter were included in this retrospective bicentric analysis. RLS severity, measured with the International RLS Study Group rating scale (IRLS), and daytime sleepiness, measured with the Epworth Sleepiness Scale (ESS), were recorded in both seasons in Innsbruck and Rome Sleep Medicine Centers.ResultsIn sum, 64 RLS patients were included. In the overall sample, IRLS in summer was higher than in winter (p = 0.008). After gender stratification, this held true only in men (p = 0.008). When stratifying for centers, the seasonal variation in RLS severity was present exclusively in Rome (p < 0.001). Moreover, 20 RLS patients completed ESS in both seasonal periods, and scores in summer were higher than in winter (p < 0.001).ConclusionThis retrospective observational study showed an increase of RLS severity during summer compared to winter, supporting the hypothesis that RLS symptoms are more troublesome when temperatures are higher. Changes in microvascular regulation, sweating, and serum iron level changes may support this difference in RLS symptoms across the year. The documented seasonal variation in RLS severity with worsening in the warmer months needs to be investigated further in prospective studies.     

Efficacy of gabapentin enacarbil in adult patients with severe primary restless legs syndrome

AimAssess efficacy and tolerability of gabapentin enacarbil (GEn) in adults with severe primary restless legs syndrome (RLS).MethodsWe pooled data from three 12-week, double-blind, placebo-controlled, randomized trials (NCT00298623, NCT00365352, NCT01332305) across GEn 600-mg, GEn 1200-mg, and placebo treatment groups for severe primary RLS (baseline International Restless Legs Scale (IRLS) total score ≥24). Co-primary end points at week 12 were mean change from baseline in IRLS total score and proportion of responders (“much”/very much” improved) on the investigator-rated Clinical Global Impression – Improvement (CGI-I) Scale. Outcomes for individual IRLS items (eg, sleep, mood, quality of life, pain, safety) were assessed.ResultsA total of 309 patients had severe primary RLS (placebo, n = 110; GEn 600 mg, n = 80; GEn 1200 mg, n = 119). GEn 600 mg and 1200 mg significantly improved least-squares mean IRLS total scores versus placebo at week 12 (placebo, −12.3; GEn 600 mg, −16.3; GEn 1200 mg, −18.0; treatment difference vs. placebo, both p <0.01). Significantly more patients with severe primary RLS treated with GEn 600 mg (64%) and 1200 mg (74%) were CGI-I responders at week 12 versus placebo (42%; p <0.01 for both GEn doses). Both GEn doses led to significant improvements in the other outcomes explored versus placebo at week 12. The most frequent treatment-emergent adverse events (TEAEs) were somnolence (GEn, 21–24%; placebo, 3%) and dizziness (GEn, 14–19%; placebo, 3%).ConclusionsGEn (600 mg or 1200 mg) once daily significantly improved RLS symptoms and consequences of these symptoms in severe primary RLS. The most frequent TEAEs were somnolence and dizziness.     

Predictors of clinical response in a double-blind placebo controlled crossover trial of gabapentin enacarbil for restless legs syndrome

ObjectivesRestless Legs Syndrome (RLS) is a sensory-motor disorder which produces sleep disturbance. Using data from a large clinical trial of gabapentin enacarbil (GEn) we sought to assess the ability of baseline, and changes from baseline, in clinical trial endpoints to predict treatment response.MethodsData were derived from a randomized, double-blind, placebo-controlled, crossover polysomnography study of gabapentin enacarbil 1200 mg (n = 121) or placebo (n = 123). Efficacy evaluations included: sleep measures from polysomnography, subjective sleep measures, Suggested Immobilization Test (SIT) measures, and International Restless Legs Severity Scale (IRLS) and Clinical Global Impression-Improvement (CGI-I). Correlations were evaluated using Spearman's rank correlation coefficients. Predictors of treatment response were separately assessed for GEn and placebo using categorical IRLS and CGI-I outcomes. Stepwise logistic regression models ascertained which combination of baseline and change from baseline variables predicted response.ResultsModerate to large correlations were observed between changes in the IRLS and changes in subjective sleep for both GEn and placebo, substantially larger for GEn than placebo. Small to moderate correlations were present between the change in IRLS and the change in SIT-discomfort for both GEn and placebo. In the stepwise regression, for both GEn and placebo, baseline and change from baseline SIT discomfort, as well as change in sleep quality, were strong predictors of response.ConclusionsChanges in sleep quality, and baseline and changes in SIT discomfort were prominent predictors of treatment response for GEn and placebo. Predictors of treatment response may allow for more targeted enrollment in future clinical trials and may provide insights into the efficacy of RLS treatments.     

A randomized,double-blind, 6-week,dose-ranging study of pregabalin in patients with restless legs syndrome

ObjectiveThis study evaluated the dose-related efficacy and safety of pregabalin in patients with idiopathic restless legs syndrome (RLS).MethodsThis six-arm, double-blind, placebo-controlled, dose–response study randomized patients (N = 137) with moderate-to-severe idiopathic RLS in an equal ratio to placebo or pregabalin 50, 100, 150, 300, or 450 mg/day. The dose–response was characterized using an exponential decay model, which estimates the maximal effect (E_max) for the primary endpoint, the change in the International Restless Legs Study Group Rating Scale (IRLS) total score from baseline to week 6 of treatment. Secondary outcomes included Clinical Global Impressions-Improvement Scale (CGI-I) responders, sleep assessments, and safety.ResultsThe separation of treatment effect between placebo and pregabalin began to emerge starting at week 1 which continued and increased through week 6 for all dose groups. The IRLS total score for pregabalin was dose dependent and well characterized for change from baseline at week 6. The model estimated 50% (ED₅₀) and 90% (ED₉₀) of the maximal effect in reducing RLS symptoms that occurred at pregabalin doses of 37.3 and 123.9 mg/day, respectively. A higher proportion of CGI-I responders was observed at the two highest doses of pregabalin (300 and 450 mg/day) versus placebo. Dizziness and somnolence were the most common adverse events and appeared to be dose-related.ConclusionsIn this 6-week phase 2b study, pregabalin reduced RLS symptoms in patients with moderate-to-severe idiopathic RLS. The symptom reduction at week 6 was dose-dependent with 123.9 mg/day providing 90% efficacy. Pregabalin was safe and well tolerated across the entire dosing range.     

Investigating the response to intravenous iron in restless legs syndrome: an observational study

ObjectiveTo investigate the effect of intravenous (IV) iron (500 mg ferric carboxymaltose [FCM] as a single dose) on restless legs syndrome (RLS) severity on a day-to-day basis.MethodsTwenty patients with RLS and absolute or functional iron deficiency or low normal serum ferritin (<45 μg/l) were included. Change of RLS severity was evaluated using the International RLS severity scale (IRLS) and the RLS-severity diary (RLS-SD) which evaluates symptom severity over a 6-h period on an 11-point numerical Likert scale, four times a day.ResultsTwelve patients reported that IV FCM improved RLS (“responders”). IRLS score decreased from 30.1 (±5.9) to 23.07 (±9.5) (p = 0.001) in the whole group and from 28.3 (±6.1) to 18.3 (±8.0) (p = 0.002) in the responder group three weeks after IV FCM treatment. A clinically relevant effect of IV iron on RLS severity could be seen as early as day eight. The responder group differed from the non-responder group in tendency by being younger (p = 0.064), having a lower serum ferritin level at baseline (p = 0.097), and presenting a lower number of comorbid conditions.ConclusionsFCM led to a considerable improvement in RLS in the responder group within about one week. These findings are clinically relevant, especially for patients with severe RLS symptoms and iron deficiency, since a change or uptitration of RLS-specific medication can be avoided or postponed in these patients due to the rapid response to IV FCM treatment.     

Open-label study of the efficacy and safety of intravenous ferric carboxymaltose in pregnant women with restless legs syndrome

ObjectiveThe objective of this study was to test the efficacy and safety of intravenous ferric carboxymaltose (FCM) in pregnant women with restless legs syndrome (RLS) and iron deficiency or anemia. The open-label pilot study (exploratory) was performed at the University Hospital of Zürich and the Neurocenter of Southern Switzerland (Lugano).Patient and MethodsNineteen women in the third trimester of pregnancy with moderate-to-severe RLS and serum ferritin levels <35 µg/l or hemoglobin (Hb) < 11.0 g/dl were included in the study. RLS was graded according to the International Restless Legs Syndrome (IRLS) Study Group rating scale. All participants had a score of ≥20 or had RLS ≥3 times/week. Based on the Hb levels, 500 or 700 mg of FCM was administered over 20 min. The primary end point was a ≥ 50% reduction in the mean IRLS score one week after FCM infusion. The secondary end points included periodic limb movements (PLMs; assessed using nocturnal foot actigraphy), sleep quality (assessed using the Pittsburgh Sleep Quality Index), and safety.ResultsThe IRLS score decreased from 23 ± 7 (baseline) to 13 ± 7 (P <0.01), whereas the PLM index decreased from 35 ± 26 (baseline) to 25 ± 20 (P <0.001). Significant improvement in sleep quality was also reported (P <0.029), and treatment was well tolerated. Three serious adverse events were reported, but they were considered unrelated to treatment.ConclusionsThese data provide promising evidence on the safety and efficacy of FCM for moderate-to-severe RLS in pregnant women with iron deficiency or anemia. Therefore, a future placebo-controlled study is warranted.     

Clinical efficacy and safety of intravenous ferric carboxymaltose treatment of pediatric restless legs syndrome and periodic limb movement disorder

BackgroundIron supplementation is the most commonly considered treatment option for children with restless legs syndrome (RLS) or periodic limb movement disorder (PLMD); however, there is a scarcity of evidence on the effectiveness of intravenous preparations. In this study, we evaluated the effectiveness and tolerability of intravenous ferric carboxymaltose (IV FCM) on clinical symptoms and iron indices in children with RLS or PLMD.MethodsThis was a single-center retrospective data analysis. Children with a diagnosis of RLS or PLMD, who underwent a single infusion of IV FCM, were included. Clinical Global Impression (CGI) Scale scores, serum ferritin, and serum iron profile at baseline and after eight weeks post infusion were obtained. Adverse effects were assessed.ResultsThirty-nine children received IV FCM, 29 with RLS and 10 with PLMD. Pre-infusion CGI-Severity revealed moderate illness, with post-infusion CGI-Improvement between “very much improved” and “much improved”. Ferritin increased from 14.6 μg/L ± 7.01 to 112.4 μg/L ± 65.86 (p < 0.00001), together with improvements in iron, total iron binding capacity, and transferrin levels from baseline to post-treatment. When compared to children with RLS, those with PLMD had a similar improvement in clinical symptoms and laboratory parameters. Seven subjects (14.3%) experienced one or two adverse events; all were mild.ConclusionsChildren with RLS and PLMD responded to IV iron supplementation with improvement in both clinical severity and laboratory parameters. Treatment was well tolerated. Although larger, randomized-controlled trials are needed, IV FCM appears to be a promising alternative to oral iron supplementation for the treatment of pediatric RLS or PLMD.     

Effect of pramipexole on RLS symptoms and sleep: a randomized, double-blind, placebo-controlled trial

BackgroundPatients with Restless Legs Syndrome (RLS) often seek treatment because of sleep problems related to nocturnal symptoms. Our goal was to test the ability of pramipexole to improve sleep in RLS patients and to reconfirm its efficacy for primary RLS symptoms.MethodsAdults with moderate or severe RLS were randomized to receive placebo or pramipexole (flexibly titrated from 0.25 to 0.75 mg), 2–3 h before bedtime for 12 weeks. The co-primary outcome measures were change in Medical Outcomes Study (MOS) sleep disturbance score and International RLS Study Group Rating Scale (IRLS) score at 12 weeks.ResultsThe intent-to-treat population included 357 patients: 178 received pramipexole and 179 received placebo. At 12 weeks, the adjusted mean change from baseline was greater for pramipexole (vs. placebo) for IRLS score (−13.4 ± 0.7 vs. −9.6 ± 0.7) and MOS sleep disturbance score (−25.3 ± 1.5 vs. −16.8 ± 1.5) (p ⩽ 0.0001; ANCOVA). Responder rates (clinical and patient global impression and IRLS) were also significantly higher in the pramipexole group. RLS-QOL score was improved over placebo at Week 12 (p < 0.01) as were MOS sleep adequacy (p = 0.0008) and quantity (p = 0.08) scores. Nine percent of patients in each group withdrew because of adverse events.ConclusionsPramipexole is effective and well-tolerated for RLS and related sleep disturbance.     

A randomized,double‐blind,placebo controlled,multi‐center study of intravenous iron sucrose and placebo in the treatment of restless legs syndrome

Iron deficiency may exacerbate symptoms in the Restless Legs Syndrome (RLS). We investigated the effect of intravenous iron sucrose or placebo on symptoms in patients with RLS and mild to moderate iron deficit. Sixty patients with primary RLS (seven males, age 46 (9) years, S‐ferritin ≤45 μg/L) recruited from a cohort of 231 patients were randomly assigned in a 12‐months double‐blind, multi‐centre study of iron sucrose 1000 mg (n = 29) or saline (n = 31). The primary efficacy variable was the RLS severity scale (IRLS) score at week 11. Median IRLS score decreased from 24 to 7 (week 11) after iron sucrose and from 26 to 17 after placebo (P = 0.123, N.S. for between treatment comparison). The corresponding scores at week 7 were 12 and 20 in the two groups (P = 0.017). Drop out rate because of lack of efficacy at 12 months was 19/31 after placebo and 5/29 patients after iron sucrose (Kaplan–Meier estimate, log rank test P = 0.0006) suggesting an iron induced superior long term RLS symptom control. Iron sucrose was well tolerated. This study showed a lack of superiority of iron sucrose at 11 weeks but found evidence that iron sucrose reduced RLS symptoms both in the acute phase (7 weeks) and during long‐term follow up in patients with variable degree of iron deficiency. Further studies on target patient groups, dosing and dosing intervals are warranted before iron sucrose could be considered for treatment of iron deficient patients with RLS. © 2009 Movement Disorder Society     

High false-positive rate of questionnaire-based restless legs syndrome diagnosis in multiple sclerosis

Background/ObjectivesRestless legs syndrome (RLS) is diagnosed by self-reported symptoms. Multiple sclerosis (MS) patients have disease-related symptoms which could mimic RLS. This study assessed the: (1) false-positive rate for questionnaire-based RLS diagnosis in MS patients and (2) utility of periodic leg movements during wakefulness (PLMW) on overnight polysomnography (PSG) in identifying true-positive RLS patients.MethodsAmbulatory MS patients without known sleep disorders were recruited. Subjects completed the International RLS Study Group (IRLSG) diagnostic questionnaire (IRLDQ) and underwent full overnight PSG. IRLDQ-positive patients underwent clinical evaluation to confirm the diagnosis and completed the RLS severity scale (IRLS).ResultsSeventy-one MS patients (mean age 46.8 ± 10.4 years) were evaluated. Thirty-eight had a positive IRLDQ. RLS diagnosis was confirmed in 22, yielding a false-positive rate of 42% [95% confidence interval (CI) 26–59%], predominantly attributable to paresthesiae (n = 7), and cramps and/or muscle spasms (n = 4). IRLS scores were not significantly different between subjects with confirmed and nonconfirmed RLS. The PLMW index was significantly higher in patients with confirmed RLS (55.4 ± 41.9 vs. 29.7 ± 18.8, p = 0.03). The sensitivity of a PLMW index >70/h for true-positive IRLDQ was 8/22 = 36%, 95% CI: 17.2–59.3, and the specificity was 16/16 = 100%, 95% CI: 79.4–100.ConclusionsMS patients have a high false-positive rate of RLS diagnosis using a standardized questionnaire largely attributable to MS-related sensorimotor symptoms. While detailed clinical evaluation is essential for confirming RLS diagnosis, the PLMW index may provide useful adjunctive information.     

Lower molecular weight intravenous iron dextran for restless legs syndrome

BackgroundVarious techniques used to assess brain iron concentrations have demonstrated the presence of low iron stores in patients with restless legs syndrome (RLS). Previous open-label and randomized studies generally support the value of iron treatment for RLS symptoms. Only one of these studies assessed iron therapy response to changes in brain iron status. The current study was designed to assess the effect of iron therapy on RLS symptoms and on CSF measures of brain iron status.MethodsIdiopathic RLS patients drawn from the Korean population received four weekly intravenous (IV) doses of 250 mg low-molecular weight iron dextran for a total dose of 1 g. One week after the last dose, any subject on RLS medication tapered off the RLS medications. Blood and CSF samples were taken to measure iron parameters at baseline and again, three weeks after the last dose. We have been following their response to the drug for two years after treatment.ResultsTwenty-five patients (age 55.2 ± 9.3, 18 female) enrolled in this study without serious adverse reactions. Seventeen of the 25 patients (68%) showed moderate or complete improvement of all RLS symptoms after treatment based on the Korean-translated versions of the International RLS Severity scale (K-IRLS). Changes in the K-IRLS did not correlate significantly with changes in CSF ferritin. The response to IV iron could not be predicted by patients’ demographics, or by blood or CSF iron baseline characteristics. RLS symptom improvement started between one and six weeks after treatment and the treatment benefits lasted from one month to 22 months. Fourteen patients, (56%) completely stopped all medications, for a mean duration of 31.3 ± 33.1 weeks. These results are comparable to those from a prior study with high molecular weight dextran.ConclusionsIntravenous low-molecular weight iron dextran produced significant improvement of RLS symptoms in a majority of patients without any significant adverse effects. Serious anaphylaxis occurs with high molecular weight, but rarely, if ever, with this low molecular weight dextran. Given apparent comparable efficacy the low molecular weight and not the high molecular weight iron dextran, should be considered for RLS treatment. Although changes in CSF ferritin were seen following therapy, these changes were not related to clinical improvements.