Efficacy and safety of pramipexole in chinese patients with restless legs syndrome: results from a multi-center, randomized, double-blind, placebo-controlled trial

Comparative Pharmacokinetics and Bioequivalence Evaluation of Two Formulations of Pramipexole Dihydrochloride Extended-Release Tablets in Healthy Chinese Subjects Under Fasted and Fed States: A Randomized, Open-Label, Single-Dose, Two-Period Crossover Clinical Trial

Background

Pramipexole dihydrochloride extended-release tablet is a novel long-acting form of non-ergot dopamine agonist indicated as one of main therapeutic approaches for Parkinson's disease. However, pharmacokinetic properties of extended-release pramipexole in healthy Chinese subjects remain unclear.

Methods

A single-center, randomized, open-label, two-period crossover, single-dose study was performed to investigate comparative pharmacokinetics and evaluate bioequivalence of 0.375 mg test (Yangtze River Pharmaceutical Group Co., Ltd.) and reference (Trade name: Sifrol®, Boehringer Ingelheim Pharma GmbH & Co. KG) formulations of pramipexole dihydrochloride extended-release tablets in healthy Chinese subjects under fasted and fed states.

Results

A total of 56 subjects (28 in each dietary trial) were enrolled and randomized. After single dose of 0.375 mg test and reference formulations under fasted condition, main pharmacokinetics of pramipexole were as follows: peak concentration (Cmax) were 409.33±95.93 and 413.77±132.03 pg/mL; plasma area under concentration-time curve from time 0 to last measurable concentration (AUC0-t) were 8801.95±1966.83 and 8646.37±2600.49 h*pg/mL; AUC from time 0 to infinity (AUC0-∞) were 9469.03±1991.61 and 9082.95±2666.26 h*pg/mL; elimination half-life (t1/2) were 11.98±3.91 and 9.85±2.63 h; both time to reach Cmax (Tmax) were about 4.50 h, respectively, for test and reference formulations. The 90% confidence intervals of geometric mean ratios (test/reference) of Cmax, AUC0-t and AUC0-∞ under fasted and fed conditions were all within 80-125%. Following administration under fed condition, Cmax and Tmax for both test and reference formulations slightly increased and prolonged to 5.0 h, respectively, but AUC approximately remained unchanged compared with dosing under fasted condition. Test and reference formulations showed similar bioequivalence and favorable safety under fasted and fed states.

Conclusion

Test and reference formulations of pramipexole dihydrochloride extended-release tablets (0.375 mg) showed similar bioequivalence and well safety and tolerability in healthy Chinese subjects under fasted and fed states, which supports further investigations of test formulation in patients with Parkinson's disease.

Clinical Evaluation of Sleep Disorders in Parkinson’s Disease

The paradigm of the framing of Parkinson’s disease (PD) has undergone significant revision in recent years, making this neurodegenerative disease a multi-behavioral disorder rather than a purely motor disease. PD affects not only the “classic” substantia nigra at the subthalamic nuclei level but also the nerve nuclei, which are responsible for sleep regulation. Sleep disturbances are the clinical manifestations of Parkinson’s disease that most negatively affect the quality of life of patients and their caregivers. First-choice treatments for Parkinson’s disease determine amazing effects on improving motor functions. However, it is still little known whether they can affect the quantity and quality of sleep in these patients. In this perspective article, we will analyze the treatments available for this specific clinical setting, hypothesizing a therapeutic approach in relation to neurodegenerative disease state.

Overview of Sleep and Circadian Rhythm Disorders in Parkinson Disease

Sleep disorders are common among PD patients and affect quality of life. They are often under-recognized and under-treated. Mechanisms of sleep disorders in PD remain relatively poorly understood. Improved awareness of common sleep problems in PD. Tailored treatment and evidence for efficacy are lacking. The purpose of this review is to provide an overview and update on the most common sleep disorders in PD. We review specific features of the most common sleep disorders in PD, including insomnia, excessive daytime sleepiness, sleep-disordered breathing, restless legs syndrome, circadian rhythm disorders and REM sleep behavior disorders.

Restless Legs Syndrome and Other Movement Disorders of Sleep-Treatment Update

PURPOSE OF REVIEW

The purpose of this review article is to summarize and discuss the recent advances in the treatment of restless legs syndrome (RLS), as well as REM sleep behavior disorder (RBD), and periodic leg movement disorder (PLMD).

RECENT FINDINGS

Traditionally, dopaminergic therapy has been considered the sole option for first-line treatment of RLS due to their impressive acute efficacy. Dopamine agonists such as oral pramipexole and ropinirole, as well as transdermal rotigotine are all effective treatment options. However, augmentation of the RLS symptoms is a major limitation of oral dopaminergic therapy. Recently, gabapentinoid agents such as gabapentin enacarbil and pregabalin have shown comparable short-term efficacy to dopaminergics with lower risk of augmentation of the RLS symptoms. Recent evidence on the efficacy of oxycodone-naloxone in treatment-resistant RLS provides an additional therapeutic avenue. The increasing understanding of the role of iron in RLS pathophysiology has led to new options in iron supplementation therapy in RLS, including treatment with ferric carboxymaltose. With emerging evidence of augmentation being a side effect specific to dopaminergic treatment, gabapentinoids are considered a safer option as initial treatment. In severe refractory RLS, oxycodone-naloxone can be used. If iron stores are low, IV iron formulations should be the initial treatment choice. New treatment options are needed to address issues with current therapies.

Disturbances of Sleep and Alertness in Parkinson's Disease

PURPOSE OF REVIEW

Parkinson's disease (PD) is the second most common neurodegenerative disorder. Sleep dysfunction is one of the most common non-motor manifestations of PD that has gained significant interest over the past two decades due to its impact on the daily lives of PD patients, poorly understood mechanisms, and limited treatment options. In this review, we discuss the most common sleep disorders in PD and present recent investigations that have broadened our understanding of the epidemiology, clinical manifestations, diagnosis, and treatment of disturbed sleep and alertness in PD.

RESENT FINDINGS

The etiology of impaired sleep-wake cycles in PD is multifactorial. Sleep dysfunction in PD encompasses insomnia, REM sleep behavior disorder, sleep-disordered breathing, restless legs syndrome, and circadian dysregulation. Despite the high prevalence of sleep dysfunction in PD, evidence supporting the efficacy of treatment strategies is limited. We are at the opportune time to advance our understanding of sleep dysfunction in PD, which will hopefully lead to mechanisms-driven interventions for better sleep and allow us to approach sleep as a modifiable therapeutic target for other non-motor and motor manifestations in PD.

Gabapentin enacarbil, pregabalin and rotigotine are equally effective in restless legs syndrome: a comparative meta-analysis

To synthesize evidence from available randomized controlled trials (RCT) to compare the efficacies of dopaminergic drugs (pramipexole, ropinirole and rotigotine) and α-2-δ ligands (gabapentin enacarbil and pregabalin) for the treatment of restless legs syndrome (RLS). We searched PubMed for all eligible RCTs. Network meta-analysis using frequentist methodology with random effect models was performed for mean changes in scores on the International RLS Study Group Rating Scale (IRLS) and for responder rates on Clinical Global Impressions-Improvement (CGI-I); analyzed as odds ratio (OR). Network meta-analysis of mean changes in IRLS data from 35 studies with 7333 participants showed that all treatments, in specific gabapentin enacarbil, followed by pregabalin and rotigotine were superior to placebo [mean reduction in IRLS scores: -5.31 (-6.74 to -3.87), -5.20 (-6.91 to -3.49), 5.17 (3.73-6.61), respectively] but there were no significant differences between active treatments. Network meta-analysis of 5137 participants from 24 studies showed that gabapentin enacarbil and rotigotine were associated with the highest CGI-I response rates [ORs: 5.68; (95% CI, 4.14-7.21); and 4.68 (2.87-6.49), compared to placebo, respectively]. No significant inter-treatment differences exist, except for that between gabapentin enacarbil and ropinirole. Based on IRLS scores and CGI-I response rates, while gabapentin enacarbil, pregabalin and rotigotine stand out as the most efficacious of all examined drugs, it is noteworthy that no significant inter-treatment differences exist, except for that between gabapentin enacarbil and ropiniriole (for CGI-I response rates).

SLEEP AND CIRCADIAN RHYTHM DISORDERS IN PARKINSON'S DISEASE

Purpose of review

Sleep disorders are among the most challenging non-motor features of Parkinson's disease (PD) and significantly affect quality of life. Research in this field has gained recent interest among clinicians and scientists and is rapidly evolving. This review is dedicated to sleep and circadian dysfunction associated with PD.

Recent findings

Most primary sleep disorders may co-exist with PD; majority of these disorders have unique features when expressed in the PD population.

Summary

We discuss the specific considerations related to the common sleep problems in Parkinson's disease including insomnia, rapid eye movement sleep behavior disorder, restless legs syndrome, sleep disordered breathing, excessive daytime sleepiness and circadian rhythm disorders. Within each of these sleep disorders, we present updated definitions, epidemiology, etiology, diagnosis, clinical implications and management. Furthermore, areas of potential interest for further research are outlined.

Practice guideline summary: Treatment of restless legs syndrome in adults: Report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology

OBJECTIVE

To make evidence-based recommendations regarding restless legs syndrome (RLS) management in adults.

METHODS

Articles were classified per the 2004 American Academy of Neurology evidence rating scheme. Recommendations were tied to evidence strength.

RESULTS AND RECOMMENDATIONS

In moderate to severe primary RLS, clinicians should consider prescribing medication to reduce RLS symptoms. Strong evidence supports pramipexole, rotigotine, cabergoline, and gabapentin enacarbil use (Level A); moderate evidence supports ropinirole, pregabalin, and IV ferric carboxymaltose use (Level B). Clinicians may consider prescribing levodopa (Level C). Few head-to-head comparisons exist to suggest agents preferentially. Cabergoline is rarely used (cardiac valvulopathy risks). Augmentation risks with dopaminergic agents should be considered. When treating periodic limb movements of sleep, clinicians should consider prescribing ropinirole (Level A) or pramipexole, rotigotine, cabergoline, or pregabalin (Level B). For subjective sleep measures, clinicians should consider prescribing cabergoline or gabapentin enacarbil (Level A), or ropinirole, pramipexole, rotigotine, or pregabalin (Level B). For patients failing other treatments for RLS symptoms, clinicians may consider prescribing prolonged-release oxycodone/naloxone where available (Level C). In patients with RLS with ferritin ≤75 μg/L, clinicians should consider prescribing ferrous sulfate with vitamin C (Level B). When nonpharmacologic approaches are desired, clinicians should consider prescribing pneumatic compression (Level B) and may consider prescribing near-infrared spectroscopy or transcranial magnetic stimulation (Level C). Clinicians may consider prescribing vibrating pads to improve subjective sleep (Level C). In patients on hemodialysis with secondary RLS, clinicians should consider prescribing vitamin C and E supplementation (Level B) and may consider prescribing ropinirole, levodopa, or exercise (Level C).

Efficacy of Pramipexole for the Treatment of Primary Restless Leg Syndrome: A Systematic Review and Meta-analysis of Randomized Clinical Trials

PURPOSE

The objective of this meta-analysis was to systematically evaluate the efficacy of pramipexole for the treatment of primary moderate-to-severe restless leg syndrome (RLS).

METHODS

Databases of PubMed, OVID, ScienceDirect, SpringerLink, Thomson Reuters Web of Science, the Cochrane Library, the Wiley Online Library, ArticleFirst, CALIS, Study, CNKI, and WanFang were searched to identify randomized controlled trials (RCTs) investigating pramipexole for the treatment of primary moderate-to-severe RLS. A meta-analysis was then conducted to pool results.

FINDINGS

Twelve RCTs involving 3286 participants were included in this study. The mean (SD) treatment duration was 11.12 (5.72) weeks/person. The meta-analysis found that the post-treatment change in the International Restless Leg Syndrome Study Group Rating Scale (IRLS) score of the pramipexole group was significantly superior to that of the placebo group (weighted mean difference [WMD] = -4.64; 95% CI, -5.95 to -3.33; n = 8). More patients in the pramipexole group reported at least a 50% reduction in the IRLS score after treatment (risk ratio [RR] = 1.57; 95% CI, 1.43 to 1.73; n = 8). In terms of the scores for the Clinical Global Impression of Improvement scale (RR = 1.48; 95% CI, 1.31 to 1.66; n = 11) and the Patient Global Impression scale (RR = 1.54; 95% CI, 1.31 to 1.81; n = 9), treatment outcomes of the pramipexole group were significantly superior to those of the placebo group. In terms of the change in quality of life (WMD = 5.39; 95% CI, 2.28 to 8.50; n = 4), the change in daytime tiredness (WMD = -0.61; 95% CI, -1.21 to -0.01; n = 4), the change in the number of periodic limb movements per hour of sleep (WMD = -35.95; 95% CI, -56.42 to -15.48; n = 3), and the change in the quality of sleep (WMD = 3.60; 95% CI, 1.69 to 5.50; n = 6), the treatment outcomes of the pramipexole group were significantly superior to those of the placebo group.

IMPLICATIONS

This meta-analysis study indicated that pramipexole could effectively improve the symptoms of patients with primary moderate-to-severe RLS, although the quality of evidence was relatively low. Future clinical trials focusing on the medium-term and long-term treatment outcomes and using mainly objective indicators for evaluation are warranted. It is also necessary to pay close attention to augmentation during medication.

Restless legs syndrome-current therapies and management of augmentation

Idiopathic restless legs syndrome (RLS) can severely affect quality of life and disturb sleep, so that pharmacological treatment is necessary, especially for elderly patients. Treatment guidelines recommend initiation of therapy with dopamine agonists (pramipexole, ropinirole or the rotigotine transdermal patch, all approved in most countries) or α-2-δ ligands (gabapentin enacarbil, approved in the USA and Japan), depending on the country and availability. Where approved, opioids (prolonged release oxycodone-naloxone, approved in Europe) are also recommended as a second-line therapy for severe RLS. Several iron formulations can be effective but are not yet approved for RLS therapy, whereas benzodiazepines and other anticonvulsants are not recommended or approved. Less is known about effective management of RLS that is associated with other conditions, such as uraemia or pregnancy. Furthermore, very little data are available on the management of RLS when first-line treatment fails or patients experience augmentation. In this Review, we summarize state-of-the-art therapies for RLS in the context of the diagnostic criteria and available guidelines, based on knowledge ranging from Class I evidence for the treatment of idiopathic RLS to Class IV evidence for the treatment of complications such as augmentation. We consider therapies, including combination therapies, that are used in clinical practice for long-term management of RLS, despite a lack of trials and approval, and highlight the need for practical long-term evaluation of current trials.

Actigraph evaluation of acupuncture for treating restless legs syndrome

We evaluated the effects of acupuncture in patients with restless legs syndrome (RLS) by actigraph recordings. Among the 38 patients with RLS enrolled, 31 (M = 12, F = 19; mean age, 47.2 ± 9.7 years old) completed the study. Patients were treated with either standard acupuncture (n = 15) or randomized acupuncture (n = 16) in a single-blind manner for 6 weeks. Changes in nocturnal activity (NA) and early sleep activity (ESA) between week 0 (baseline), week 2, week 4, and week 6 were assessed using leg actigraph recordings, the International Restless Legs Syndrome Rating Scale (IRLSRS), and Epworth Sleepiness Scale (ESS). Standard but not randomized acupuncture reduced the abnormal leg activity of NA and ESA significantly in week 2, week 4, and week 6 based on the changes in the clinical scores for IRLSRS and ESS in week 4 and week 6 compared with the baseline. No side effects were observed. The results indicate that standard acupuncture might improve the abnormal leg activity in RLS patients and thus is a potentially suitable integrative treatment for long-term use.

Pramipexole for Chinese people with primary restless legs syndrome: a 12-week multicenter, randomized, double-blind study

BACKGROUND

Restless legs syndrome (RLS) often responds to agents that enhance dopamine neurotransmission. The present 12-week study aimed to evaluate the efficacy and adverse events of pramipexole (PPX) for the treatment of adult, Chinese people with primary RLS.

METHODS

A total of 204 Chinese people with RLS were randomly assigned to receive either the placebo or PPX (flexibly titrated from 0.25 mg to 0.75 mg), 2 h to 3 h before bedtime for 12 weeks. The primary measuring outcomes were the International RLS Study Group Rating Scale (IRLS) and the Clinical Global Impressions-Improvement (CGI-I) scale. The secondary outcome was adverse events.

RESULTS

One hundred and ninety participants completed the study. At 12 weeks, the adjusted mean (SE) change from baseline was greater for PPX (vs placebo) for the IRLS score (-13.2 ± 0.7 vs -9.4 ± 0.6; p <0.01), and (-12.1 ± 0.6 vs -8.3 ± 0.6; p <0.01) at the end of one month follow-up after treatment. The CGI-I rating of "very much improved" or "much improved" in the percentage of participants (61.8% vs 34.3%; p <0.01), and (51.0% vs 26.5%; p <0.01) after week 12, and one month follow-up of treatment, respectively. The proportion of adverse events was 60.8% in the PPX group and 45.1% in the placebo group. No deaths related to PPX treatment were recorded.

CONCLUSIONS

In summary, the present study showed that PPX is efficacious and well tolerated in Chinese people with primary RLS.

A mixed treatment comparison of gabapentin enacarbil, pramipexole, ropinirole and rotigotine in moderate-to-severe restless legs syndrome

OBJECTIVE

A mixed treatment comparison (MTC) was performed to investigate the relative efficacy and safety of licensed pharmaceuticals for moderate-to-severe restless legs syndrome (RLS).

METHODS

RLS trials published over the past 10 years were identified via systematic literature searches of MEDLINE, Embase, Cochrane CENTRAL, and manufacturers' websites. MTC was performed with WinBUGS software using a Bayesian approach. Identified primary outcomes: change in International RLS Study Group Rating Scale (IRLS) at week 12 and end of maintenance (EoM).

SECONDARY OUTCOMES

IRLS and Clinical Global Impression - Improvement Scale (CGI-I) responders, RLS-6 items and adverse events (AEs).

RESULTS

Twenty-eight clinical trials were identified. Fifteen were included in the primary analysis. Indirect comparisons were established among gabapentin enacarbil, pramipexole, ropinirole, rotigotine and placebo. Overall, the four active treatments showed similar efficacies as assessed by changes in IRLS scores, IRLS responders, CGI-I responders, and RLS-6 scores. The sole exception was change in IRLS at week 12, for which rotigotine was likely more efficacious than ropinirole (mean difference: -2.52 [95% CrI: -4.74, -0.40]). Indirect comparisons on safety endpoints indicated ropinirole was associated with a higher risk of nausea than the other agents, and was more likely to result in discontinuations due to lack of efficacy than pramipexole. Nausea was likely more frequent with pramipexole than gabapentin enacarbil, and rotigotine was more likely to result in discontinuation due to AEs than ropinirole and pramipexole.

CONCLUSIONS

This MTC confirmed the superiority of gabapentin enacarbil, pramipexole, ropinirole, and rotigotine above placebo in alleviating RLS symptoms. Compared to ropinirole, rotigotine showed some additional benefit in terms of change in IRLS at Week 12. Choice of RLS drugs requires careful evaluation of effectiveness and safety profiles in clinical practice. Due to lack of head-to-head trials, inconsistency could not be assessed in our analysis. Head-to-head trials on a more homogeneous population are needed to validate the MTC results.

Pramipexole induced psychosis in a patient with restless legs syndrome

In the last few years, dopamine agonists (DA) have been used as first-line treatment for restless legs syndrome (RLS), a disabling sensorimotor disorder. Only recently have they reported some possible iatrogenic side effects, as shown below. The following case presents a RLS patient who developed hallucinatory and delusional symptoms with paranoid ideation after pramipexole assumption; these symptoms gradually decreased after pramipexole suspension and treatment by an oral antipsychotic therapy (quetiapine XR). Correlation between DAs assumption and psychotic symptoms is still not clear. The development of these side effects might be related to many risk factors such as genetic susceptibility, premorbid personality and psychosocial stressor; in order to minimise the risk of iatrogenic psychosis it could be useful to assess patients' vulnerability factors selecting an alternative medication regime.

Efficacy and tolerability of pramipexole for the treatment of primary restless leg syndrome: a meta-analysis of randomized placebo-controlled trials

Primary restless leg syndrome (RLS) is a common sensory-motor disorder that is characterized by an irresistible urge to move the limbs and unpleasant sensations in the legs, which affects 1.9%-4.6% adults. Pramipexole, a potent dopamine D2/3 agonist, is recommended as "effective" in the short-term and "possibly effective" in the long-term treatment of primary RLS in the European guidelines on management of RLS. In this meta-analysis, we summarized the efficacy and tolerability of pramipexole in treatment for primary RLS. Results of this meta-analysis showed a favorable effect of pramipexole versus placebo on RLS symptoms (mean change on International RLS Study Group Rating Scale [IRLS] score: mean difference [MD] = -5.96; 95% confidence interval [CI]: -7.79 to -4.41, P < 0.00001) and sleep quality (pooled standard mean difference [SMD] = -0.48, 95% CI: -0.61 to -0.35, P < 0.00001). Nausea (relative risk [RR] = 2.68, 95% CI: 1.82 to 3.95, P < 0.001) and fatigue (RR = 1.82, 95% CI: 1.14 to 2.93, P = 0.013) were the most common adverse events, but, by and large, pramipexole was well-tolerated in patients with primary RLS. Nevertheless, long-term studies and more evidence of head-to-head comparisons of pramipexole with other dopamine agonists, anticonvulsants, and levodopa are needed.