Which dyskinesia scale best detects treatment response?

Numerous scales assess dyskinesia in Parkinson's disease (PD), variably focusing on anatomical distribution, phenomenology, time, severity, and disability. No study has compared these scales and their relative ability to detect change related to an established treatment. We conducted a randomized placebo‐controlled trial of amantadine, assessing dyskinesia at baseline and at 4 and 8 weeks using the following scales: Unified Dyskinesia Rating Scale (UDysRS), Lang‐Fahn Activities of Daily Living Dyskinesia Rating Scale (LF), 26‐Item Parkinson's Disease Dyskinesia scale (PDD‐26), patient diaries, modified Abnormal Involuntary Movements Scale (AIMS), Rush Dyskinesia Rating Scale (RDRS), dyskinesia items from the Movement Disorder Society–sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS‐UPDRS), and Clinical Global Impression (severity and change: CGI‐S, CGI‐C). Scale order was randomized at each visit, but raters were aware of each scale as it was administered. Sensitivity to treatment was assessed using effect size. Sixty‐one randomized dyskinetic PD subjects (31 amantadine, 30 placebo) completed the study. Four of the 8 scales (CGI‐C, LF, PDD‐26, and UDysRS) detected a significant treatment. The UDysRS Total Score showed the highest effect size (η² = 0.138) for detecting treatment‐related change, with all other scales having effect sizes < 0.1. No scale was resistant to placebo effects. This study resolves 2 major issues useful for future testing of new antidyskinesia treatments: among tested scales, the UDysRS, having both subjective and objective dyskinesia ratings, is superior for detecting treatment effects; and the magnitude of the UDysRS effect size from amantadine sets a clear standard for comparison for new agents. © 2012 Movement Disorder Society     

Early treatment benefits of ropinirole prolonged release in Parkinson's disease patients with motor fluctuations

We performed a retrospective analysis of the Efficacy And Safety Evaluation in Parkinson's Disease (EASE‐PD) Adjunct Study, assessing the minimum time to symptom improvement after initiation of ropinirole prolonged release (2–24 mg/day) versus placebo in patients with moderate‐to‐advanced PD not optimally controlled with levodopa. Ropinirole prolonged release was superior to placebo at Week 2 for change from baseline in “off” time (adjusted mean treatment difference [AMTD] – 0.7 hours; 95% confidence interval [CI], –1.1, –0.2; P = 0.0029), and “on” time without troublesome dyskinesia (0.4 hours; 95%CI, 0.01, 0.88; P = 0.0444). At Week 4, improvements were seen in change from baseline in Unified Parkinson's Disease Rating Scale total motor score (AMTD, –3.1; 95%CI, –4.4, –1.8; P < 0.0001), activities of daily living score (AMTD, –1.1; 95%CI, –1.7, –0.5; P = 0.0004), and the cardinal symptoms of PD compared with placebo. These analyses indicate that once‐daily, adjunctive ropinirole prolonged release can offer PD symptom control 2 weeks after treatment initiation. © 2010 Movement Disorder Society     

Two‐year,randomized, controlled study of safinamide as add‐on to levodopa in mid to late Parkinson's disease

In a 6‐month double‐blind, placebo‐controlled study of Parkinson's disease patients with motor fluctuations, safinamide 50 and 100 mg/d significantly increased ON‐time without increasing dyskinesia. Further long‐term safinamide use in these patients was evaluated over an additional 18 months. Patients continued on their randomized placebo, 50, or 100 mg/d safinamide. The primary endpoint was change in Dyskinesia Rating Scale total score during ON‐time over 24 months. Other efficacy endpoints included change in ON‐time without troublesome dyskinesia, changes in individual diary categories, depressive symptoms, and quality of life measures. Change in Dyskinesia Rating Scale was not significantly different in safinamide versus placebo groups, despite decreased mean total Dyskinesia Rating Scale with safinamide compared with an almost unchanged score in placebo. Ad hoc subgroup analysis of moderate to severe dyskinetic patients at baseline (36% of patients) showed a decrease with safinamide 100 mg/d compared with placebo (P = 0.0317). Improvements in motor function, activities of daily living, depressive symptoms, clinical status, and quality of life at 6 months remained significant at 24 months. Adverse events and discontinuation rates were similar with safinamide and placebo. This 2‐year, controlled study of add‐on safinamide in mid‐to‐late Parkinson's disease with motor fluctuations, although not demonstrating an overall difference in dyskinesias between patients and controls, showed improvement in dyskinesia in patients at least moderately dyskinetic at baseline. The study additionally demonstrated significant clinical benefits in ON‐time (without troublesome dyskinesia), OFF‐time, activities of daily living, motor symptoms, quality of life, and symptoms of depression. © 2014 International Parkinson and Movement Disorder Society     

Study of istradefylline in patients with Parkinson's disease on levodopa with motor fluctuations

The objective of this study was to evaluate the efficacy, safety, and tolerability of istradefylline 20 mg once daily versus placebo as an adjunct to levodopa in subjects with Parkinson's disease (PD) who have motor fluctuations. Istradefylline (KW‐6002) is an adenosine A_2A receptor antagonist that in primate models of PD improves motor function without causing or worsening dyskinesia. This 12‐week, multicenter, double‐blind, placebo‐controlled, randomized, Phase 3 study of istradefylline was conducted in subjects experiencing an average daily OFF time of at least 3 hours (116 randomized to istradefylline; 115 to placebo). All were on stable levodopa regimens; 90% were also on stable regimens of other anti‐Parkinson's medications. Istradefylline‐treated subjects had significant placebo‐corrected reductions in daily OFF time from baseline to endpoint: 4.6% (P = 0.03) and 0.7 hours (P = 0.03). For ON time with troublesome dyskinesia, the changes between istradefylline and placebo were not significant. Istradefylline was well tolerated, with 6 (5.2%) istradefylline‐treated and 7 (6.1%) placebo‐treated subjects withdrawing from the study because of adverse events. Dyskinesia, lightheadedness, tremor, constipation, and weight decrease were reported more often with istradefylline than placebo. We conclude that istradefylline is well tolerated and significantly reduces OFF time as an adjunct to levodopa in PD subjects with motor fluctuations. © 2008 Movement Disorder Society     

Levodopa‐carbidopa intestinal gel in advanced Parkinson's disease: Final 12‐month,open‐label results

Motor complications in Parkinson's disease (PD) are associated with long‐term oral levodopa treatment and linked to pulsatile dopaminergic stimulation. l ‐dopa‐carbidopa intestinal gel (LCIG) is delivered continuously by percutaneous endoscopic gastrojejunostomy tube (PEG‐J), which reduces l‐ dopa‐plasma–level fluctuations and can translate to reduced motor complications. We present final results of the largest international, prospective, 54‐week, open‐label LCIG study. PD patients with severe motor fluctuations (>3 h/day “off” time) despite optimized therapy received LCIG monotherapy. Additional PD medications were allowed >28 days post‐LCIG initiation. Safety was the primary endpoint measured through adverse events (AEs), device complications, and number of completers. Secondary endpoints included diary‐assessed off time, “on” time with/without troublesome dyskinesia, UPDRS, and health‐related quality‐of‐life (HRQoL) outcomes. Of 354 enrolled patients, 324 (91.5%) received PEG‐J and 272 (76.8%) completed the study. Most AEs were mild/moderate and transient; complication of device insertion (34.9%) was the most common. Twenty‐seven (7.6%) patients withdrew because of AEs. Serious AEs occurred in 105 (32.4%), most commonly complication of device insertion (6.5%). Mean daily off time decreased by 4.4 h/65.6% (P < 0.001). On time without troublesome dyskinesia increased by 4.8 h/62.9% (P < 0.001); on time with troublesome dyskinesia decreased by 0.4 h/22.5% (P = 0.023). Improvements persisted from week 4 through study completion. UPDRS and HRQoL outcomes were also improved throughout. In the advanced PD population, LCIG's safety profile consisted primarily of AEs associated with the device/procedure, l‐ dopa/carbidopa, and advanced PD. LCIG was generally well tolerated and demonstrated clinically significant improvements in motor function, daily activities, and HRQoL sustained over 54 weeks. © 2014 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.     

Mavoglurant (AFQ056) in combination with increased levodopa dosages in Parkinson's disease patients

Long-term use of levodopa (L-dopa) in patients with Parkinson's disease is associated with development of dyskinesia. This study explored whether Parkinson's disease patients with L-dopa-induced dyskinesia experience improved OFF-time from higher L-dopa doses without worsening of dyskinesias when receiving adjunctive mavoglurant. Patients with moderate-to-severe L-dopa-induced dyskinesia were randomized to receive mavoglurant or placebo. Mavoglurant (AFQ056) was up-titrated over two weeks from 25 mg twice daily (bid) to 100 mg bid (L-dopa kept stable), followed by three weeks during which the daily L-dopa dosage was increased by up to 300 mg/day. A sample size of 30 was initially planned; however, the study was terminated prematurely due to enrollment challenges. OFF-time showed greater improvements in the mavoglurant group (n = 7) compared with the placebo group (n = 7); difference at week 5 was –2.77 h (90% confidence interval –5.44, –0.09 h; p = 0.09). ON-time without troublesome dyskinesia increased more from baseline to week 5 in the mavoglurant group (4.38 h) versus the placebo group (0.63 h). Clinician-rated measures were conflicting. The Modified Abnormal Involuntary Movement Scale scores showed a slight improvement with mavoglurant compared with placebo, while the Unified Dyskinesia Rating Scale parts III and IV worsened slightly with mavoglurant compared with placebo. Due to the low patient numbers and conflicting clinician-rated outcomes data, our findings are not conclusive. However, our results suggest that mavoglurant combined with higher doses of L-dopa may be effective in treating patients with Parkinson's disease experiencing L-dopa-related motor fluctuations and dyskinesias.     

Randomized trial of safinamide add‐on to levodopa in Parkinson's disease with motor fluctuations

Levodopa is effective for the motor symptoms of Parkinson's disease (PD), but is associated with motor fluctuations and dyskinesia. Many patients require add‐on therapy to improve motor fluctuations without exacerbating dyskinesia. The objective of this Phase III, multicenter, double‐blind, placebo‐controlled, parallel‐group study was to evaluate the efficacy and safety of safinamide, an α‐aminoamide with dopaminergic and nondopaminergic mechanisms, as add‐on to l ‐dopa in the treatment of patients with PD and motor fluctuations. Patients were randomized to oral safinamide 100 mg/day (n = 224), 50 mg/day (n = 223), or placebo (n = 222) for 24 weeks. The primary endpoint was total on time with no or nontroublesome dyskinesia (assessed using the Hauser patient diaries). Secondary endpoints included off time, Unified Parkinson's Disease Rating Scale (UPDRS) Part III (motor) scores, and Clinical Global Impression‐Change (CGI‐C). At week 24, mean ± SD increases in total on time with no or nontroublesome dyskinesia were 1.36 ± 2.625 hours for safinamide 100 mg/day, 1.37 ± 2.745 hours for safinamide 50 mg/day, and 0.97 ± 2.375 hours for placebo. Least squares means differences in both safinamide groups were significantly higher versus placebo. Improvements in off time, UPDRS Part III, and CGI‐C were significantly greater in both safinamide groups versus placebo. There were no significant between‐group differences for incidences of treatment‐emergent adverse events (TEAEs) or TEAEs leading to discontinuation. The addition of safinamide 50 mg/day or 100 mg/day to l ‐dopa in patients with PD and motor fluctuations significantly increased total on time with no or nontroublesome dyskinesia, decreased off time, and improved parkinsonism, indicating that safinamide improves motor symptoms and parkinsonism without worsening dyskinesia. © 2013 International Parkinson and Movement Disorder Society     

Double‐blind study of pardoprunox,a new partial dopamine agonist,in early Parkinson's disease

This study examined the efficacy and safety of the partial dopamine agonist, pardoprunox (SLV308), in the treatment of patients with early Parkinson's disease (PD). Patients were randomized to receive pardoprunox (n = 69) or placebo (n = 70). Pardoprunox was titrated to each patient's optimal dose (9–45 mg/d) over 2 to 6 weeks and then maintained at this dose for a further 3 weeks. Concomitant anti‐Parkinson treatment was not permitted. In the primary analysis, Unified PD Rating Scale (UPDRS)‐Motor score was improved in pardoprunox‐treated patients (overall mean dose 23.8 mg/d; ?7.3 points), as compared with placebo (?3.0 points; P = 0.0001), from baseline to end point. At end point, there were more responders (≥30% reduction in UPDRS‐Motor score) in the pardoprunox group (50.7%) than in the placebo group (15.7%; P < 0.0001). In other secondary analyses, UPDRS‐activities of daily living (ADL) and ‐ADL+Motor scores were also significantly more improved in the pardoprunox group. Nausea was reported by 32 of 68 (47.1%) pardoprunox‐treated patients (vs. 3/70, 4.3%, placebo‐treated patients), with dizziness, somnolence, headache, and asthenia also reported by ≥10 patients. In this exploratory proof‐of‐concept study, pardoprunox significantly improved motor function in patients with early PD. The efficacy and safety profile of pardoprunox justifies its further investigation in PD. © 2010 Movement Disorder Society     

Task force report on scales to assess dyskinesia in Parkinson's disease: Critique and recommendations

Drug‐induced dyskinesia is a common phenomenon in Parkinson's disease (PD) and is often socially as well as physically disabling for patients. The Movement Disorders Society commissioned a task force to assess available clinical rating scales, critique their clinimetric properties, and make recommendations regarding their clinical utility. A task force composed six clinical researchers who systematically searched the literature for scales measuring dyskinesia in PD, evaluated the scales' previous use, performance parameters, and quality of validation data (if available). A scale was designated “Recommended” if the scale has been used in clinical studies beyond the group that developed it, has been specifically used in PD reports, and if clinimetric studies have established that it is a valid, reliable, and sensitive. “Suggested” scales met two of the above criteria and those meeting one were “Listed.” Based on the systematic review, eight rating scales for dyskinesia that have either been validated or used in PD were identified. These were the Abnormal Involuntary Movement Scale (AIMS), The Unified Parkinson's Disease Rating Scale (UPDRS) part IV, the Obeso Dyskinesia Rating Scale, the Rush Dyskinesia Rating Scale, the Clinical Dyskinesia Rating Scale (CDRS), the Lang‐Fahn Activities of Daily Living Dyskinesia Scale, the Parkinson Disease Dyskinesia Scale (PDYS‐26), and the Unified Dyskinesia Rating Scale (UDysRS). Based on this review, at present two of the reviewed dyskinesia scales (AIMS and the Rush Dyskinesia Rating Scale) fulfill criteria for Recommended for use in PD populations, albeit weakly so; all of the remaining met criteria to be Suggested. However, the two most recent scales (PDYS‐26 and UDysRS) have excellent clinimetric properties and appear to provide a reliable and valid assessment tool of dyskinesia in PD. If they are used successfully beyond the groups that developed them, both have the potential to be re‐ranked as Recommended. As further testing of these scales in PD is warranted, no new scales are needed until the available scales are fully tested clinimetrically. © 2010 Movement Disorder Society     

AFQ056 in Parkinson patients with levodopa‐induced dyskinesia: 13‐week,randomized, dose‐finding study

AFQ056 is a novel, selective metabotropic glutamate receptor 5 antagonist. This was a 13‐week, double‐blind, placebo‐controlled study. Patients with Parkinson's disease and moderate‐to‐severe levodopa (l ‐dopa)‐induced dyskinesia who were receiving stable l ‐dopa/anti‐parkinsonian treatment and were not currently receiving amantadine were randomized to receive either AFQ056 (at doses of 20, 50, 100, 150, or 200 mg daily) or placebo (1:1:1:1:2:3 ratio) for 12 weeks. The primary outcome was the modified Abnormal Involuntary Movements Scale. Secondary outcomes included the 26‐item Parkinson's Disease Dyskinesia Scale, the Patient's/Clinician's Global Impression of Change, and the Unified Parkinson's Disease Rating Scale parts III (motor evaluation) and IV (severity of motor complications). Safety was assessed. In total, 98 of 133 (73.7%) AFQ056‐treated patients and 47 of 64 (73.4%) patients in the placebo group completed the study. Baseline characteristics were comparable. Patients randomized to AFQ056 200 mg daily administered in 2 doses demonstrated significant improvements at Week 12 on the modified Abnormal Involuntary Movements Scale compared with placebo (difference, ?2.8; 95% confidence interval [CI], ?5.2, ?0.4; P = 0.007). Based on final actual doses, there was a dose‐response relationship on the modified Abnormal Involuntary Movements Scale, with 200 mg daily demonstrating the most robust effect (difference, ?3.6; 95% CI, ?7.0, ?0.3; P = 0.012). Improvements in dyskinesia were supported by change on Unified Parkinson's Disease Rating Scale part IV item 32 (50 mg daily: difference, ?0.7; 95% CI, ?1.1, ?0.2; P = 0.003; 200 mg daily: difference, ?0.5; 95% CI, ?0.8, ?0.1; P = 0.005). No significant changes were observed on the 26‐item Parkinson's Disease Dyskinesia Scale, the Unified Parkinson's Disease Rating Scale part IV item 33 or items 32 and 33, or the Patient's/Clinician's Global Impression of Change. Unified Parkinson's Disease Rating Scale part III scores were not significantly changed, indicating no worsening of motor symptoms. The most common adverse events (with incidence greater with AFQ056 than with placebo) were dizziness, hallucination, fatigue, nasopharyngitis, diarrhea, and insomnia. AFQ056 demonstrated anti‐dyskinetic efficacy in this population without worsening underlying motor symptoms. These results will guide dose selection for future clinical trials. © 2013 International Parkinson and Movement Disorder Society     

The Unified Dyskinesia Rating Scale: Presentation and clinimetric profile

We developed and tested a rating scale aimed to capture the essential features of dyskinesia in Parkinson's disease (PD). Although several scales assess selected attributes of PD‐dyskinesias, no comprehensive rating tool exists. Available rating scales were evaluated by the investigators and patient focus groups. Modifications were finalized into the Unified Dyskinesia Rating Scale (UDysRS). The UDysRS has four parts: I: Historical Disability (patient perceptions) of On‐Dyskinesia impact (maximum 44 points); II: Historical Disability (patient perceptions) of Off‐Dystonia impact (maximum 16 points); III: Objective Impairment (dyskinesia severity, anatomical distribution over seven body regions, and type (choreic or dystonic) based on four activities observed or video‐recorded (28 points); IV: Objective Disability based on Part III activities (maximum 16 points). For clinimetric testing, 70 PD patients with all severities of dyskinesia were interviewed and videotaped. Twenty movement disorder experts rated the videotapes with the UDysRS. Internal consistency was examined with Cronbach's alpha. Inter‐ and intra‐rater reliability was evaluated with generalized weighted and nonweighted Kappa coefficients, and intraclass correlation coefficients. Both subjective (Sections I and II) and objective (Sections III and IV) demonstrated high internal consistency (alpha: 0.915, 0.971). Interrater reliability for the objective sections was acceptable for all items and likewise for intrarater reliability except for right leg. Reliable factor structures were found for both subjective (six factors) and objective sections (five factors). The UDysRS is a clinimetrically sound rating scale for dyskinesia in PD, demonstrating acceptable levels of internal consistency and inter‐ and intra‐rater reliability. Testing scale responsivity to treatment interventions is planned. © 2008 Movement Disorder Society     

AFQ056 treatment of levodopa‐induced dyskinesias: Results of 2 randomized controlled trials

Study objectives were to assess the efficacy, safety, and tolerability of AFQ056 in Parkinson's disease patients with levodopa‐induced dyskinesia. Two randomized, double‐blind, placebo‐controlled, parallel‐group, in‐patient studies for Parkinson's disease patients with moderate to severe levodopa‐induced dyskinesia (study 1) and severe levodopa‐induced dyskinesia (study 2) on stable dopaminergic therapy were performed. Patients received 25–150 mg AFQ056 or placebo twice daily for 16 days (both studies). Study 2 included a 4‐day down‐titration. Primary outcomes were the Lang‐Fahn Activities of Daily Living Dyskinesia Scale (study 1), the modified Abnormal Involuntary Movement Scale (study 2), and the Unified Parkinson's Disease Rating Scale–part III (both studies). Secondary outcomes included the Unified Parkinson's Disease Rating Scale–part IV items 32–33. The primary analysis was change from baseline to day 16 on all outcomes. Treatment differences were assessed. Fifteen patients were randomized to AFQ056 and 16 to placebo in study 1; 14 patients were randomized to each group in study 2. AFQ056‐treated patients showed significant improvements in dyskinesias on day 16 versus placebo (eg, Lang‐Fahn Activities of Daily Living Dyskinesia Scale, P = .021 [study 1]; modified Abnormal Involuntary Movement Scale, P = .032 [study 2]). No significant changes were seen from baseline on day 16 on the Unified Parkinson's Disease Rating Scale‐part III in either study. Adverse events were reported in both studies, including dizziness. Serious adverse events (most commonly worsening of dyskinesias, apparently associated with stopping treatment) were reported by 4 AFQ056‐treated patients in study 1, and 3 patients (2 AFQ056‐treated patient and 1 in the placebo group) in study 2. AFQ056 showed a clinically relevant and significant antidyskinetic effect without changing the antiparkinsonian effects of dopaminergic therapy. © 2011 Movement Disorder Society     

Rotigotine effects on early morning motor function and sleep in Parkinson's disease: A double‐blind,randomized, placebo‐controlled study (RECOVER)

In a multinational, double‐blind, placebo‐controlled trial (NCT00474058), 287 subjects with Parkinson's disease (PD) and unsatisfactory early‐morning motor symptom control were randomized 2:1 to receive rotigotine (2–16 mg/24 hr [n = 190]) or placebo (n = 97). Treatment was titrated to optimal dose over 1–8 weeks with subsequent dose maintenance for 4 weeks. Early‐morning motor function and nocturnal sleep disturbance were assessed as coprimary efficacy endpoints using the Unified Parkinson's Disease Rating Scale (UPDRS) Part III (Motor Examination) measured in the early morning prior to any medication intake and the modified Parkinson's Disease Sleep Scale (PDSS‐2) (mean change from baseline to end of maintenance [EOM], last observation carried forward). At EOM, mean UPDRS Part III score had decreased by ?7.0 points with rotigotine (from a baseline of 29.6 [standard deviation (SD) 12.3] and by ?3.9 points with placebo (baseline 32.0 [13.3]). Mean PDSS‐2 total score had decreased by ?5.9 points with rotigotine (from a baseline of 19.3 [SD 9.3]) and by ?1.9 points with placebo (baseline 20.5 [10.4]). This represented a significantly greater improvement with rotigotine compared with placebo on both the UPDRS Part III (treatment difference: ?3.55 [95% confidence interval (CI) ?5.37, ?1.73]; P = 0.0002) and PDSS‐2 (treatment difference: ?4.26 [95% CI ?6.08, ?2.45]; P < 0.0001). The most frequently reported adverse events were nausea (placebo, 9%; rotigotine, 21%), application site reactions (placebo, 4%; rotigotine, 15%), and dizziness (placebo, 6%; rotigotine 10%). Twenty‐four‐hour transdermal delivery of rotigotine to PD patients with early‐morning motor dysfunction resulted in significant benefits in control of both motor function and nocturnal sleep disturbances. © 2010 Movement Disorder Society     

Onset of dyskinesia with adjunct ropinirole prolonged‐release or additional levodopa in early Parkinson's disease

Levodopa‐induced dyskinesia can result in significant functional disability and reduced quality of life in patients with Parkinson's disease (PD). The goal of this study was to determine if the addition of once‐daily ropinirole 24‐hour prolonged‐release (n = 104) in PD patients not optimally controlled with levodopa after up to 3 years of therapy with less than 600 mg/d delays the onset of dyskinesia compared with increasing doses of levodopa (n = 104). During the study, 3% of the ropinirole prolonged‐release group (mean dose 10 mg/d) and 17% of the levodopa group (mean additional dose 284 mg/d) developed dyskinesia (P < 0.001). There were no significant differences in change in Unified Parkinson's Disease Rating Scale activities of daily living or motor scores, suggesting comparable efficacy between the two treatments. Adverse events were comparable in the two groups with nausea, dizziness, insomnia, back pain, arthralgia, somnolence, fatigue, and pain most commonly reported. Ropinirole prolonged‐release delayed the onset of dyskinesia with comparable efficacy to increased doses of levodopa in early PD patients not optimally controlled with levodopa. © 2010 Movement Disorder Society     

Adenosine A2A receptor antagonist istradefylline (KW-6002) reduces "off" time in Parkinson's disease: a double-blind, randomized, multicenter clinical trial (6002-US-005)

Objective

Based on new understanding of nondopaminergic pathways involved in Parkinson's disease (PD) pathophysiology, a selective adenosine A_2A receptor antagonist, istradefylline, shows promise for the treatment of PD.

Methods

Istradefylline (40mg/day) was studied in levodopa‐treated PD subjects experiencing prominent wearing‐off motor fluctuations. At 23 North American sites, 196 subjects were randomized in a double‐blind, 12‐week outpatient clinical trial of istradefylline (114 completing the trial) or placebo (58 completing the trial). The primary efficacy measure was change from baseline to end point in the percentage of daily awake “off” time, recorded by subjects using a patient PD diary. Secondary end points evaluated “on” time (including “on time with dyskinesia”), the Unified Parkinson's Disease Rating Scale, and a Clinical Global Impression–Improvement of Illness score. Clinical laboratory, electrocardiograms, vital signs, and adverse event monitoring comprised the safety monitoring.

Results

After randomization, approximately 88% of subjects completed the double‐blind period. Compared with baseline, the decrease of daily awake “off” time for istradefylline was a mean (± standard deviation) of ?10.8 ± 16.6% (95% confidence interval, ?13.46 to ?7.52) and for placebo, ?4.0 ± 15.7% (95% confidence interval, ?7.73–0.31; p = 0.007 using two‐way analysis of variance). This effect corresponded to changes from baseline in total daily awake “off” time of ?1.8 ± 2.8 hours for istradefylline and ?0.6 ± 2.7 hours for placebo (p = 0.005). Treatment‐emergent adverse effects with istradefylline were generally mild.

Interpretation

Istradefylline was safe, well tolerated, and offered a clinically meaningful reduction in “off” time without increased troublesome dyskinesia. Ann Neurol 2008

     

Macrogol for the treatment of constipation in Parkinson's disease. A randomized placebo‐controlled study

Chronic constipation is the most frequent symptom of autonomic system involvement in Parkinson's disease (PD). Quite often the symptom is severe and impairs patients' quality of life. The objective of this study is to determine the efficacy and safety of an isosmotic macrogol solution for the treatment of constipation in PD patients, in a double‐blind, placebo‐controlled study. A total of 57 PD patients with constipation were randomly assigned to receive an isosmotic macrogol electrolyte solution (MC‐ES; 29 patients) or placebo (28 patients) for 8 weeks. Treatment efficacy was defined as complete relief of the symptom or a marked improvement of two of the following indicators: stool frequency, straining, stool consistency, use of rectal laxatives as a rescue therapy. The responder rates were significantly higher in the MC‐ES group both at the first (4 weeks; P < 0.0003) and at the final evaluation (8 weeks; P < 0.0012). The frequency of bowel movements (P < 0.002) and stool consistency (P < 0.006) were significantly changed in the MC‐ES group compared to the placebo group. At the final evaluation, a rectal laxative was used by 2 (12.5%) patients on placebo, whereas no use was recorded in the MC‐ES group. Responder rate for straining showed a favorable trend in patients treated with macrogol versus placebo. Unified Parkinson's Disease Rating Scale Part III and Parkinson's Disease Questionnaire (PDQ‐39) did not show any significant modification in either group during the 8‐week treatment period. The results of this placebo‐controlled study show the efficacy of MC‐ES in the treatment of constipation in PD. MC‐ES was well‐tolerated and did not affect the course of PD. © 2006 Movement Disorder Society     

Clinical efficacy of istradefylline (KW‐6002) in Parkinson's disease: A randomized,controlled study

The objectives of this study were to evaluate the efficacy of istradefylline at an oral dose of 20 mg or 40 mg once daily for 12 weeks in Parkinson's disease (PD) patients with motor complications on levodopa therapy based on the change in the daily OFF time compared with placebo and to assess the safety at these doses. A total of 363 subjects were randomly assigned to receive 20 mg/day istradefylline (n = 119), 40 mg/day istradefylline (n = 125), or placebo (n = 119). The primary outcome variable was the change from baseline at endpoint in daily OFF time based on patients' ON/OFF diaries. At endpoint, the daily OFF time reduced from baseline by 1.31 hours for 20 mg/day istradefylline (P = 0.013 as compared to the placebo), 1.58 hours for 40 mg/day istradefylline (P < 0.001), and 0.66 hours for placebo; istradefylline significantly reduced the daily OFF time compared with placebo. The UPDRS Part III subscale score (ON state) reduced by 5.7 at endpoint in both istradefylline groups and 3.7 in the placebo group (P = 0.006 for 20 mg/day and P = 0.006 for 40 mg/day group as compared with placebo). The most commonly reported drug‐related treatment emergent adverse event (TEAE) was dyskinesia, which occurred in 2.5% (3/119) of subjects receiving placebo, 8.5% (10/118) receiving 20 mg/day istradefylline, and 6.4% (8/125) receiving 40 mg/day istradefylline. We conclude that istradefylline at 20 mg and 40 mg once daily is effective in relieving wearing‐off fluctuations of PD patients. In addition, istradefylline was well tolerated at both doses. © 2010 Movement Disorder Society     

Phase II safety,tolerability, and dose selection study of isradipine as a potential disease‐modifying intervention in early Parkinson's disease (STEADY‐PD)

Isradipine, a dihydropyridine calcium channel antagonist, has been shown to be neuroprotective in animal models of Parkinson's disease (PD). To establish a dosage of isradipine controlled‐release (CR) that is tolerable and demonstrates preliminary efficacy for use in a future pivotal efficacy trial a Phase 2, randomized, double‐blind, parallel group trial (Safety, Tolerability and Efficacy Assessment of Dynacirc CR in Parkinson Disease [STEADY‐PD]) was undertaken in subjects with early PD not requiring dopaminergic therapy (dopamine agonists or levodopa) randomized 1:1:1:1 to 5, 10, or 20 mg of isradipine CR or matching placebo daily. The primary outcome was tolerability defined as no more than a 30% difference in the proportion of patients completing the study on the originally assigned dosage between an active and placebo group. If more than one isradipine dosage was tolerable, then a 3‐point difference in total Unified Parkinson's Disease Rating Scale (UPDRS) change between baseline and week 52 (or time to sufficient disability to require dopaminergic therapy) was taken as a criterion for selection of the most desirable dosage for future study. STEADY‐PD enrolled 99 subjects. The tolerability of isradipine was dose dependent: placebo, 25 of 26 patients (96%); 5 mg, 19 of 23 patients (83%); 10 mg 19 of 26 patients (73%); and 20 mg 9 of 24 patients (37%). There was no difference in change in UPDRS among dosages. The most common adverse events were peripheral edema (30) and dizziness (24). Isradipine 10 mg daily was the maximal tolerable dosage in this study of early PD. A large placebo‐controlled trial will be necessary and is planned to assess efficacy of isradipine 10 mg daily to slow progression of PD disability. © 2013 International Parkinson and Movement Disorder Society.     

Trial of dextromethorphan/quinidine to treat levodopa‐induced dyskinesia in Parkinson's disease

Background : Nondopaminergic pathways represent potential targets to treat levodopa‐induced dyskinesia in Parkinson's disease (PD). This pilot‐study (NCT01767129) examined the safety/efficacy of the sigma‐1 receptor‐agonist and glutamatergic/monoaminergic modulator, dextromethorphan plus quinidine (to inhibit rapid dextromethorphan metabolism), for treating levodopa‐induced dyskinesia. Methods : PD patients were randomized to dextromethorphan/quinidine (45 mg/10 mg twice daily)/placebo in two 2‐week double‐blind, crossover treatment periods, with intervening 2‐week washout. After 14 days, a 2‐hour intravenous levodopa‐infusion was administered. Patient examinations were videotaped before infusion (“off” state) and every 30 minutes during and afterwards until patients returned to “off.” The primary endpoint was dyskinesia‐severity during infusion measured by Unified Dyskinesia Rating Scale part 3 area‐under‐curve scores (blinded expert rated). Additional endpoints included other dyskinesia/motor assessments, global measures of clinical‐change, and adverse‐events. Results : A total of 13 patients were randomized and completed the study (efficacy‐evaluable population). Dyskinesia‐severity was nonsignificantly lower with dextromethorphan/quinidine than placebo during infusion (area‐under‐curve 966.5 vs 1048.8; P = .191 [efficacy‐evaluable patients]), and significantly lower in a post‐hoc sensitivity analysis of the per‐protocol‐population (efficacy‐evaluable patients with ≥ 80% study‐drug‐compliance, n = 12) when measured from infusion start to 4‐hours post–infusion completion (area‐under‐curve 1585.0 vs 1911.3; P = .024). Mean peak dyskinesia decreased significantly from infusion‐start to return to “off” (13.3 vs 14.9; P = .018 [efficacy‐evaluable patients]). A total of 9 patients rated dyskinesia “much/very much improved” on dextromethorphan/quinidine versus 1‐patient on placebo. Dextromethorphan/quinidine did not worsen PD‐motor scores, was generally well tolerated, and was associated with more frequent adverse events. Conclusion : This study provides preliminary evidence of clinical benefit with dextromethorphan/quinidine for treating levodopa‐induced dyskinesia in PD. Larger studies with a longer treatment duration need to corroborate these early findings. © 2017 International Parkinson and Movement Disorder Society     

Teaching program for the Unified Dyskinesia Rating Scale

The Unified Dyskinesia Rating Scale (UDysRS) has been introduced as a comprehensive rating tool for the evaluation of dyskinesias in Parkinson's disease (PD). To enhance a uniform application, we developed a DVD‐based training program with instructions, patient examples, and a certification exercise. For training on the objective assessment of dyskinesia, seventy PD patients spanning the gamut of dyskinesias (none to severe) were videotaped during four tasks of daily living (speaking, drinking from a cup, putting on a coat, and walking). Dyskinesia severity in seven body parts was rated by 20 international movement disorder specialists using the UDysRS for impairment. Each task was also rated for disability. Inter‐rater reliability was assessed with generalized weighted kappa and intraclass correlation coefficients. For the teaching program, examples of each severity level and each body part were selected based on the criterion that they received a uniform rating (± 1 point) by at least 75% of the raters. For the certification exercise, four cases were selected to represent the four quartiles of overall objective UDysRS scores to reflect slight, mild, moderate, and severe dyskinesia. Each selection was based on the highest inter‐rater reliability score for that quartile (minimum kappa or intraclass correlation coefficient = 0.6). UDysRS ranges for certification were calculated based on the 95% confidence interval. The teaching program lasts 41 min, and the certification exercise requires 10 min (total 51 min). This training program, based on visual examples of dyskinesia and anchored in scores generated by movement disorder experts is aimed at increasing homogeneity of ratings among and within raters and centers. Large‐scale multicenter randomized clinical trials of dyskinesia treatment are strengthened by a uniform standard of scale application. © 2009 Movement Disorder Society