Pardoprunox in early Parkinson's disease: results from 2 large, randomized double-blind trials

This report presents the results of 2 randomized trials-Rembrandt and Vermeer-on the efficacy and safety of pardoprunox in patients with early Parkinson's disease. Patients with Parkinson's disease with a Unified Parkinson's Disease Rating Scale-Motor score ≥ 10 and modified Hoehn and Yahr stage ≤ 3 were randomized to pardoprunox (fixed doses of 6 mg/day [n = 115] or 12 mg/day [n = 118] or a flexible-dose range of 12-42 mg/day [n = 116]) or placebo (n = 119) in Rembrandt and pardoprunox 12-42 mg/day (n = 108), pramipexole 1.5-4.5 mg/day (n = 116), or placebo (n = 110) in Vermeer. Pardoprunox showed a significant benefit over placebo in the primary efficacy variable, least-square mean change from baseline in Unified Parkinson's Disease Rating Scale-Motor score: Rembrandt-fixed doses of 6 and 12 mg/day, -6.0 and -4.7 points, respectively; flexible-dose 12-42 mg/day, -5.5 points; placebo, -2.9 points; Vermeer-flexible-dose 12-42 mg/day, -4.9 points; placebo, -2.5 points; pramipexole, -5.7 points. No minimum effective dose was established. Secondary efficacy parameters supported the results of the primary efficacy variable. Pardoprunox tolerability was dose related: flexible-dose 12-42 mg/day showed the highest dropout rate due to treatment-emergent adverse events (Rembrandt, 56.0%; Vermeer, 46.3%) and overall incidence of treatment-emergent adverse events (Rembrandt, 97.4%; Vermeer, 92.6%), primarily due to nausea, somnolence, and dizziness. Because pardoprunox showed similar efficacy across all dose groups, these observations suggest that the 12-42 mg/day dose range was higher than therapeutically required. Furthermore, the early onset of treatment-emergent adverse events and dropouts observed for pardoprunox suggest that titration was too rapid. Pardoprunox significantly improved motor symptoms in patients with early Parkinson's disease, but further investigation into the dose and titration schedule is required to improve tolerability.

Preladenant in patients with Parkinson's disease and motor fluctuations: a phase 2, double-blind, randomised trial

BACKGROUND

Preladenant is an adenosine 2A (A₂(A)) receptor antagonist. In animal models of Parkinson's disease, preladenant monotherapy improves motor function without causing dyskinesia and, as an adjunct to levodopa, it improves motor function without worsening dyskinesia. We aimed to assess the efficacy and safety of preladenant in patients with Parkinson's disease and motor fluctuations who were receiving levodopa and other antiparkinsonian drugs.

METHODS

In this phase 2, dose-finding trial, patients with Parkinson's disease who were receiving levodopa were enrolled and treated at 44 sites in 15 countries between December, 2006, and November, 2008. Assignment to treatment was done centrally with an interactive voice response system, according to a block randomisation schedule that was computer generated by the sponsor. Patients were assigned to receive 1, 2, 5, or 10 mg oral preladenant twice daily, or matching placebo for 12 weeks. Patients, study staff, investigators, and all sponsor personnel were masked to treatment assignment. The primary outcome was change in mean daily off time from baseline to week 12, as assessed by home diaries. Efficacy analysis included all patients who received at least one dose of study drug and had data for assessments after baseline. This trial is registered with ClinicalTrials.gov, number NCT00406029.

FINDINGS

253 patients were randomised to receive preladenant (1 mg [n=49], 2 mg [n=49], 5 mg [n=49], 10 mg [n=57]) or placebo (n=49), of whom 234 on preladenant (1 mg [n=47], 2 mg [n=48], 5 mg [n=45], 10 mg [n=49]) and placebo (n=45) were eligible for the efficacy analysis. Mean daily off time from baseline to week 12 was reduced versus placebo in patients on 5 mg preladenant (difference -1·0 h, 95% CI -2·1 to 0·0; p=0·0486) and 10 mg preladenant (-1·2 h, -2·2 to -0·2; p=0·019). Changes in mean daily off time versus placebo were not significant for 1 mg preladenant (0·2 h, -0·9 to 1·2; p=0·753) or 2 mg preladenant (-0·7 h, -1·7 to 0·3; p=0·162). The most common adverse events in the combined preladenant group versus placebo were worsening of Parkinson's disease (22 [11%] vs 4 [9%]), somnolence (20 [10%] vs 3 [6%]), dyskinesia (18 [9%] vs 6 [13%]), nausea (17 [9%] vs 5 [11%]), constipation (15 [8%] vs 1 [2%]), and insomnia (15 [8%] vs 4 [9%]).

INTERPRETATION

5 and 10 mg preladenant twice daily might be clinically useful to reduce off time in patients with Parkinson's disease and motor fluctuations.

FUNDING

Schering-Plough, a subsidiary of Merck.

Determination of minimal clinically important change in early and advanced Parkinson's disease

Two common primary efficacy outcome measures in Parkinson's disease (PD) are change in Unified Parkinson's Disease Rating Scale (UPDRS) scores in early PD and change in "off" time in patients with motor fluctuations. Defining the minimal clinically important change (MCIC) in these outcome measures is important to interpret the clinical relevance of changes observed in clinical trials and other situations. We analyzed data from 2 multicenter, placebo-controlled, randomized clinical trials of rasagiline; TEMPO studied 404 early PD subjects, and PRESTO studied 472 levodopa-treated subjects with motor fluctuations. An anchor-based approach using clinical global impression of improvement (CGI-I) was used to determine MCIC for UPDRS scores and daily "off" time. MCIC was defined as mean change in actively treated subjects rated minimally improved on CGI-I. Receiver operating characteristic (ROC) curves defined optimal cutoffs discriminating between changed and unchanged subjects. MCIC for improvement in total UPDRS score (parts I-III) in early PD was determined to be -3.5 points based on mean scores and -3.0 points based on ROC curves. In addition, we found an MCIC for reduction in "off" time of 1.0 hours as defined by mean reduction in "off" time in active treated subjects self-rated as minimally improved on CGI-I minus mean reduction in "off" time in placebo-treated subjects self-rated as unchanged (1.9-0.9 hours). We hypothesize that many methodological factors can influence determination of the MCIC, and a range of values is likely to emerge from multiple studies.

The independent influence of apathy and depression on cognitive functioning in Parkinson's disease

OBJECTIVE

The purpose of the present study was to examine the independent influence of symptoms of depression and apathy, two of the most common neuropsychiatric symptoms in Parkinson's disease (PD), on executive functioning and memory in PD patients using measures designed to discriminate between these symptoms.

METHOD

Participants included 68 nondemented, idiopathic PD patients, ages 56-82 years. The Apathy Evaluation Scale-Self-Rating and select items of the Beck Depression Inventory II were used to assess symptoms of apathy and depression, respectively. Cognitive function was assessed using the Wisconsin Card Sorting Test and Hopkins Verbal Learning Test-Revised. Correlations and hierarchical regressions were conducted to investigate the relationships between apathy, depression, and cognitive function. Hierarchical regression analyses were conducted to evaluate the degree of influence of depression and apathy on cognitive function.

RESULTS

Results revealed that symptoms of apathy, but not depression, were significantly and negatively associated with executive functioning. Immediate memory was significantly and negatively associated with both apathy and depression. However, apathy accounted for additional variance in memory performance after controlling for depression at a level approaching significance.

CONCLUSIONS

Apathy is not only associated with cognitive impairment, but also with impaired daily functioning, caregiver burden and distress, medication noncompliance, and increased mortality. Differentiating apathy and depression, understanding their unique effects, and appropriately identifying apathy symptoms in patients have robust implications for the development of neuropsychological models of these effects in PD as well as practical implications in guiding improvements to patient care and enhancing quality of life in patients and caregivers.

Long-term, open-label study of once-daily ropinirole prolonged release in early Parkinson's disease

Long-term safety and efficacy of once-daily ropinirole prolonged release (PR) were evaluated in subjects with early Parkinson's disease (PD). Subjects (n = 83) who completed one of two studies were enrolled in this open-label, multicenter, extension study, and followed for up to 78 months. Ropinirole PR was titrated/continued, and adjusted as appropriate during the maintenance phase (maximum 24 mg/day). L-dopa and other non-dopamine agonist PD medications were permitted. Safety outcomes included adverse events (AEs). Efficacy outcomes included Unified Parkinson's Disease Rating Scale (UPDRS) II and III scores, and Clinical Global Impression-Severity (CGI-S) and Improvement (CGI-I) scores. The median duration of ropinirole PR exposure was 1,069 days. Most subjects (97.6%) reported at least one AE, most commonly (≥ 30%) nausea (42.2%), dizziness (41.0%), peripheral edema (38.6%), back pain (33.7%), and headache (31.3%). Seventeen (20.5%) subjects discontinued due to an AE. UPDRS and CGI scores indicated that the clinical status of subjects was maintained throughout the treatment period. In patients with early PD, long-term treatment with once-daily ropinirole PR was not associated with any new safety concerns, and was effective in maintaining clinical status. These results support the extended use of ropinirole PR for treatment of PD.

Long-term efficacy of rasagiline in early Parkinson's disease

This study was designed to follow the long-term efficacy, safety, and tolerability of rasagiline for Parkinson's disease (PD) with data collected from all patients who had ever taken rasagiline during the 12-month TEMPO monotherapy trial (N = 398) and subsequent open-label extension. Patients were followed for up to 6.5 years with a mean of 3.5 +/- 2.1 years. After 12 months, additional PD medications were added as required. Of patients remaining in the trial at 2 years, 46% were maintained on rasagiline monotherapy. The majority of patients received a dopamine agonist prior to levodopa as the first additional dopaminergic agent. Analysis using a Kaplan-Meier method indicated that by 5.4 years only 25% of patients progressed to Hoehn & Yahr stage III. Rasagiline was well tolerated, with 11.3% of patients (45/398) withdrawing because of an adverse event. Rasagiline therapy for PD was effective, well tolerated, and safe in this long-term trial.

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.

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.

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 (> or = 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 > or = 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.

Early pharmacologic treatment in Parkinson's disease

Early treatment of Parkinson's disease (PD) affords an opportunity to forestall clinical progression. Levodopa is the most effective treatment for PD motor signs and symptoms, but its use is associated with the development of motor fluctuations and dyskinesias. Because of this, levodopa use is commonly withheld until the patient experiences functional disability. Other medications are available for the treatment of early PD and can be initiated at or near the time of diagnosis. Monoamine oxidase type B (MAO-B) inhibitors provide mild symptomatic benefit, delay the need for levodopa, are very well tolerated, and may provide long-term disease-modifying effects. Dopamine agonists provide moderate symptomatic benefit, delay the need for levodopa, and cause fewer motor complications than levodopa. Compared with levodopa, however, dopamine agonists cause more somnolence and sudden-onset sleep as well as impulse control disorders. The treatment of early PD depends in part on the individual patient's anticipated risk of side effects and the degree of motor improvement required. Physicians should also consider the early use of MAO-B inhibitors in light of their very good tolerability and the recent evidence suggesting long-term disease-modifying effects.

Improving symptom control in early Parkinson's disease

Motor symptoms in Parkinson's disease (PD) are caused by a severe loss of pigmented dopamine-producing nigro-striatal neurons. Symptomatic therapies provide benefit for motor features by restoring dopamine receptor stimulation. Studies have demonstrated that delaying the introduction of dopaminergic medical therapy is associated with a rapid decline in quality of life. Nonmotor symptoms, such as depression, are common in early PD and also affect quality of life. Therefore, dopaminergic therapy should typically be initiated at, or shortly following, diagnosis. Monamine oxidase-B inhibitors provide mild symptomatic benefit, have excellent side effect profiles, and may improve long-term outcomes, making them an important first-line treatment option. Dopamine agonists (DAs) provide moderate symptomatic benefit but are associated with more side effects than levodopa. However, they delay the development of motor complications by delaying the need for levodopa. Levodopa (LD) is the most efficacious medication, but its chronic use is associated with the development of motor complications that can be difficult to resolve. Younger patients are more likely to develop levodopa-induced motor complications and they are therefore often treated with a DA before levodopa is added. For older patients, levodopa provides good motor benefit with a relatively low-risk of motor complications. Using levodopa with a dopa-decarboxylase inhibitor lessens adverse effects, and further adding a catechol-O-methyl transferase inhibitor can improve symptom control.

Occupation and risk of parkinsonism: a multicenter case-control study

BACKGROUND

We examined risk of parkinsonism in occupations (agriculture, education, health care, welding, and mining) and toxicant exposures (solvents and pesticides) putatively associated with parkinsonism.

OBJECTIVE

To investigate occupations, specific job tasks, or exposures and risk of parkinsonism and clinical subtypes.

DESIGN

Case-control.

SETTING

Eight movement disorders centers in North America.

PARTICIPANTS

Inclusion criteria were parkinsonism (>or=2 cardinal signs), diagnosis within 8 years of recruitment (to minimize survival bias), and ability to participate in detailed telephone interviews. Control subjects were primarily nonblood relatives or acquaintances of patients.

MAIN OUTCOME MEASURES

This multicenter case-control study compared lifelong occupational and job task histories to determine associations with parkinsonism and certain clinical subtypes (postural instability and gait difficulty and age at diagnosis <or=50 years).

RESULTS

Findings in 519 cases and 511 controls were analyzed. Work in agriculture, education, health care, or welding was not associated with increased risk of parkinsonism. Unexpected increased risks associated with legal, construction and extraction, or religious occupations were not maintained after adjustment for duration. Risk of parkinsonism increased with pesticide use (odds ratio, 1.90; 95% confidence interval, 1.12-3.21), use of any of 8 pesticides mechanistically associated with experimental parkinsonism (2.20; 1.02-4.75), and use of 2,4-dichlorophenoxyacetic acid (2.59; 1.03-6.48). None of the specific occupations, job tasks, or task-related exposures were associated with younger age at diagnosis (<or=50 years). Ever working in business and finance, legal occupations, construction and extraction, or transportation and material moving was associated with postural instability and gait difficulty subtype of parkinsonism. Tobacco use was inversely associated with parkinsonism risk.

CONCLUSION

The association of disease risk with pesticides support a toxicant-induced cause of parkinsonism.

Randomized, double-blind, pilot evaluation of intravenous glutathione in Parkinson's disease

The objective of this study was to evaluate the safety, tolerability, and preliminary efficacy of intravenous glutathione in Parkinson's disease (PD) patients. This was a randomized, placebo-controlled, double-blind, pilot trial in subjects with PD whose motor symptoms were not adequately controlled with their current medication regimen. Subjects were randomly assigned to receive intravenous glutathione 1,400 mg or placebo administered three times a week for 4 weeks. Twenty-one subjects were randomly assigned, 11 to glutathione and 10 to placebo. One subject who was assigned to glutathione withdrew from the study for personal reasons prior to undergoing any postrandomization efficacy assessments. Glutathione was well tolerated and there were no withdrawals because of adverse events in either group. Reported adverse events were similar in the two groups. There were no significant differences in changes in Unified Parkinson's Disease Rating Scale (UPDRS) scores. Over the 4 weeks of study medication administration, UPDRS ADL + motor scores improved by a mean of 2.8 units more in the glutathione group (P = 0.32), and over the subsequent 8 weeks worsened by a mean of 3.5 units more in the glutathione group (P = 0.54). Glutathione was well tolerated and no safety concerns were identified. Preliminary efficacy data suggest the possibility of a mild symptomatic effect, but this remains to be evaluated in a larger study.

Double-blind trial of levodopa/carbidopa/entacapone versus levodopa/carbidopa in early Parkinson's disease

We performed a 39-week, randomized, double-blind, multicenter study to compare the efficacy, safety, and tolerability of levodopa/carbidopa/entacapone (LCE, Stalevo) with levodopa/carbidopa (LC, Sinemet IR) in patients with early Parkinson's disease (PD). Four hundred twenty-three patients with early PD warranting levodopa were randomly assigned to treatment with LCE 100/25/200 or LC 100/25 three-times daily. The adjusted mean difference in total Unified Parkinson's disease Rating Scale (UPDRS) Parts II and III between groups using the analysis of covariance model (prespecified primary outcome measure) was 1.7 (standard error = 0.84) points favoring LCE (P = 0.045). Significantly greater improvement with LCE compared with LC was also observed in UPDRS Part II activities of daily living (ADL) scores (P = 0.025), Schwab and England ADL scores (blinded rater, P = 0.003; subject, P = 0.006) and subject-reported Clinical Global Impression (CGI) scores (P = 0.047). There was no significant difference in UPDRS Part III or investigator-rated CGI scores. Wearing-off was observed in 29 (13.9%) subjects in the LCE group and 43 (20.0%) in the LC group (P = 0.099). Dyskinesia was observed in 11 (5.3%) subjects in the LCE group and 16 (7.4%) in the LC group (P = 0.367). Nausea and diarrhea were reported more frequently in the LCE group. LCE provided greater symptomatic benefit than LC and did not increase motor complications.

Safety and tolerability of pardoprunox, a new partial dopamine agonist, in a randomized, controlled study of patients with advanced Parkinson's disease

AIMS

To investigate the safety and tolerability of pardoprunox (SLV308), a novel partial dopamine agonist, as an adjunct to levodopa in patients with advanced Parkinson's disease, using two titration schedules.

METHODS

Patients were randomized to pardoprunox (n = 51) or placebo (n = 11). Pardoprunox was titrated to the highest tolerated dose (range, 0.3-42 mg/day) over 7 weeks, using a gradual dose escalation without intermediate steps (group 1) or with intermediate steps (group 2).

RESULTS

The cumulative drop-out rate was greater in group 1 (without intermediate steps, 56.0%) than in group 2 (with intermediate steps, 34.6%), or with placebo (9.1%). In group 2, doses up to 18 mg/day were well tolerated with a cumulative drop-out rate of 7.7% (2/26) and a drop-out rate due to adverse events of 4.0% (1/26). The most common adverse events reported were nausea, vomiting, headache, and dizziness. There was a trend for reduced OFF time (p = 0.054) in the combined pardoprunox group compared to placebo.

CONCLUSIONS

The pardoprunox safety and tolerability profile as an adjunct to levodopa was improved using a gradual titration schedule that included intermediate dose steps. Using this titration, doses up to 18 mg/day were well tolerated.

Transplanted dopaminergic neurons develop PD pathologic changes: a second case report

This report describes pathological changes within the grafted neurons of another patient with Parkinson's disease (PD) who died 14 years posttransplantation. Although numerous healthy appearing grafted neurons were present at this long-term time point, some displayed Lewy bodies as evidenced by alpha-synuclein, ubiquitin, and thioflavin-S staining. Additionally, there was a general loss of dopamine transporter-immunoreactivity in grafted neurons. Some grafted cell displayed a loss of tyrosine hydroxylase. These data support the emerging concept that PD-like pathology is seen in young grafted neurons when they survive long term.

A randomized, double-blind, placebo-controlled, delayed start study to assess rasagiline as a disease modifying therapy in Parkinson's disease (the ADAGIO study): rationale, design, and baseline characteristics

A neuroprotective therapy is the single most important unmet medical need in Parkinson's disease. Several promising agents in the laboratory have been tested in the clinic, but none has been established in clinical trials to have a disease modifying effect despite positive results because of potential confounding symptomatic or pharmacologic effects. The delayed start design was developed to try to avoid a symptomatic confound when testing a putative neuroprotective therapy. In this study design, patients are randomly assigned to study drug or placebo in the first phase of the study, and both groups receive the active drug in the second phase. If benefits seen at the end of phase I persist through the end of phase II, they cannot be readily explained by a symptomatic effect (as patients in both groups are receiving the same medication) and benefits in the early start group must relate to the early initiation of the treatment. Although the precise mechanism responsible for such an effect can be debated, positive results in a delayed start study indicate that patients who receive early treatment have a better outcome than those where the treatment is delayed. We are using the delayed start design to assess the potential disease modifying effects of rasagiline in a prospective double blind controlled trial (the ADAGIO study). We here describe the rationale for the study and baseline characteristics of the 1,176 patients who have been enrolled into the trial.

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.

Sleep disorders in Parkinson's disease

Sleep disorders occur commonly in Parkinson's disease (PD), and reduce quality of life. Sleep-related problems in PD include insomnia, restless legs syndrome, rapid eye movement sleep behavior disorder, sleep apnea, parasomnias, excessive daytime sleepiness, and sleep attacks. This article reviews sleep disorders and their treatment in PD.

Levodopa: past, present, and future

Levodopa has been the mainstay of treatment for Parkinson's disease (PD) for more than 40 years. During this time, researchers have strived to optimize levodopa formulations to minimize side effects, enhance central nervous system (CNS) bioavailability, and achieve stable therapeutic plasma levels. Current strategies include concomitant treatment with inhibitors of dopa decarboxylase (DDC) and catechol-O-methyltransferase (COMT) to prolong the peripheral levodopa half-life and increase CNS bioavailability. Levodopa combined with DDC inhibition is the current standard method of delivering levodopa for symptomatic treatment of PD. Recent research suggests that continuous dopaminergic stimulation that more closely approximates physiological stimulation may delay or prevent the development of motor fluctuations ('wearing off') and dyskinesias. Strategies currently being used to achieve more continuous dopaminergic stimulation include the combination of an oral levodopa/DDC inhibitor with a COMT inhibitor and the enteral infusion of a levodopa gel formulation. Attempts are underway to develop oral and transdermal very long-acting levodopa preparations.

Placebo response in Parkinson's disease: comparisons among 11 trials covering medical and surgical interventions

Placebo-associated improvements have been previously documented in small series of Parkinson's disease (PD) patients. Using a strict definition of placebo-associated improvement, we examined rates and timing of placebo responses to identify patient- and study-based characteristics, predicting positive placebo response in several PD clinical trials. We collected individual patient data from the placebo groups of 11 medical and surgical treatment trials involving PD patients with differing PD severities and placebo-assignment likelihoods. We defined a positive placebo response as > or = 50% improvement in total Unified Parkinson's Disease Rating Scale motor (UPDRSm) score or a decrease by > or = 2 points on at least two UPDRSm items compared to baseline. We calculated positive placebo response rates at early (3-7 weeks), mid (8-18 weeks), and late (23-35 weeks) stages of follow-up. Odds ratios for patient- and study-based characteristics were obtained from a model fitted using generalized estimating equations. There were 858 patients on placebo who met inclusion criteria for analysis. Three studies involved patients without need of symptomatic treatment, two involved patients without motor fluctuations needing symptomatic treatment, and six (three medical and three surgical) involved patients with motor fluctuations. The overall placebo response rate was 16% (range: 0-55%). Patients with higher baseline UPDRSm scores and studies that focused on PD with motor fluctuations, surgical interventions, or those with a higher probability of placebo assignment showed increased odds of positive placebo response. Placebo responses were temporally distributed similarly during early, mid, and late phases of follow-up. Placebo-related improvements occur in most PD clinical trials and are similarly distributed across all 6 months of follow-up. Recognition of factors that impact placebo response rates should be incorporated into individual study designs for PD clinical trials.

Levodopa-induced dyskinesias in Parkinson's disease: etiology, impact on quality of life, and treatments

Levodopa is the most effective agent to alleviate motor dysfunction in Parkinson's disease but its long-term use is associated with the development of dyskinesias. Although the pathogenic processes behind the development of levodopa-induced dyskinesias are still being elucidated, it appears that chronic administration of this short-lived agent results in nonphysiologic pulsatile stimulation of striatal neurons and abnormal firing patterns in the basal ganglia. Dyskinesias have been associated with decreased quality of life, and a number of methodologies to evaluate severity of dyskinesias are now available. Strategies to avoid, reduce, or eliminate dyskinesias include providing more continuous dopaminergic stimulation, administering an antidyskinetic agent, and surgery. Several new compounds that may provide an antidyskinetic effect are also under investigation.

Lewy body-like pathology in long-term embryonic nigral transplants in Parkinson's disease

Fourteen years after transplantation into the striatum of an individual with Parkinson's disease, grafted nigral neurons were found to have Lewy body-like inclusions that stained positively for alpha-synuclein and ubiquitin and to have reduced immunostaining for dopamine transporter. These pathological changes suggest that Parkinson's disease is an ongoing process that can affect grafted cells in the striatum in a manner similar to host dopamine neurons in the substantia nigra. These findings have implications for cell-based therapies and for understanding the cause of Parkinson's disease.

Ten-year follow-up of Parkinson's disease patients randomized to initial therapy with ropinirole or levodopa

In a 5-year, double-blind study, subjects with Parkinson's disease (PD) who were randomized to initial treatment with ropinirole had a significantly lower incidence of dyskinesia compared with subjects randomized to levodopa, although Unified Parkinson's Disease Rating Scale (UPDRS) motor scores were significantly more improved in the levodopa group. Subjects who completed the original study were eligible to participate in a long-term extension study conducted according to an open, naturalistic design and were evaluated approximately every 6 months until they had been followed for a total of 10 years. Comparing subjects randomized to initial treatment with ropinirole (n = 42) and levodopa (n = 27), the incidence of dyskinesia was significantly lower in the ropinirole group (adjusted odds ratio [OR] = 0.3; 95% confidence interval [CI]: 0.1, 1.0; P = 0.046) and the median time to dyskinesia was significantly longer (adjusted hazard ratio = 0.4; 95% CI: 0.2, 0.8; P = 0.007). The incidence of at least moderate wearing off ("off" time >/=26% of the awake day) was also significantly lower in the ropinirole group (adjusted OR = 0.3; 95% CI: 0.09, 0.03; P = 0.03). There were no significant differences in change in UPDRS activities of daily living or motor scores, or scores for the 39-item PD questionnaire, Clinical Global Impression, or the Epworth Sleepiness Scale. Early treatment decisions for individual patients depend largely on the anticipated risk of side effects and long-term complications. Both ropinirole and levodopa are viable treatment options in early PD.

Role of the pharmacist in the effective management of wearing-off in Parkinson's disease

OBJECTIVE

To evaluate the role of the practicing pharmacist in the identification and current treatment of the levodopa wearing-off phenomenon experienced by patients with Parkinson's disease (PD) who are receiving chronic levodopa therapy.

DATA SOURCES

Literature retrieval was accessed through MEDLINE (1967-June 2007) using the terms levodopa, wearing-off, and Parkinson's disease. In addition, reference citations from publications identified were reviewed.

STUDY SELECTION AND DATA EXTRACTION

All articles that were identified from the data sources and written in English were evaluated.

DATA SYNTHESIS

Levodopa is the most efficacious therapeutic agent in PD; however, the response of patients to levodopa changes over time. Eventually, the duration of response becomes shorter and more unpredictable, and complications emerge. One of the first complications observed with levodopa therapy is wearing-off, which can emerge within 1-3 years of initiation of levodopa treatment. Wearing-off is characterized by the predictable emergence of motor and nonmotor PD symptoms before the next scheduled dose of medication. Despite effective treatment options to tackle wearing-off, it remains underrecognized and under treated. With early identification and optimization of treatment, wearing-off can be managed effectively, resulting in improved quality of life for patients with PD.

CONCLUSIONS

Owing to their training and accessibility, pharmacists play an increasingly important role in the management of patients with PD. Pharmacists are uniquely placed to identify wearing-off, offer timely advice, and facilitate the optimization of treatment regimens to improve patients' quality of life and enhance long-term outcomes.

A pilot, double-blind, placebo-controlled trial of pregabalin (Lyrica) in the treatment of essential tremor

We performed a pilot, double-blind, placebo-controlled, randomized trial to evaluate the efficacy and tolerability of pregabalin (PGB, Lyrica), an antiepileptic agent, in treating essential tremor (ET). Twenty two patients with ET were randomly assigned to receive PGB or placebo. PGB was initiated at 50 mg/day and was escalated by 75 mg/day every 4 days to a maximum dose of 600 mg/day. Patients were evaluated by accelerometry and the Fahn-Tolosa-Marin (FTM) rating scale. There was a significant reduction in tremor amplitude in the PGB group compared with the placebo group, as measured by accelerometry, at a mean dose of 286.76+/-100.05 mg/day. Action tremor limb scores on the FTM also improved in the PGB group compared with the placebo group (P-value for multilevel modeling=0.04). PGB was fairly well tolerated, with about one-third of patients dropping out of the study because of adverse events. PGB provided significant improvements in accelerometry and in action tremor limb scores on the FTM. However, larger studies are needed to further evaluate the potential effect of PGB on ET.

Levodopa-induced Dyskinesia in Parkinson’s disease: Epidemiology, etiology, and treatment

Although levodopa is the gold standard for treating motor symptoms of Parkinson's disease (PD), long-term therapy leads to levodopa-induced dyskinesia (LID). Dyskinesia refers to involuntary movements other than tremor and most commonly consists of chorea that occurs when levodopa-derived dopamine is peaking in the brain ("peak-dose dyskinesia"). However, dyskinesia can also consist of dystonia or myoclonus and occur during other parts of the levodopa dosing cycle. New validated rating scales and home diaries can better help the health care provider assess the timing and severity of dyskinesia. The exact etiology of LID is unknown, but there is evidence that abnormal pulsatile stimulation of dopamine receptors may be contributory. Treatment of LID includes adjustment of PD medications to maximize "on" time without troublesome dyskinesia. Amantadine is the only medication available with demonstrated ability to reduce the expression of established LID without reducing antiparkinsonian benefit. Other medications that are currently being studied to treat established LID include antiepileptics and serotonergic medications. Deep brain stimulation of the subthalamic nucleus is now the most commonly used surgical procedure for PD patients, and it is very effective in treating LID.

Social Security Disability Insurance (SSDI) in Parkinson's disease

OBJECTIVE

Parkinson's disease (PD) causes significant economic burden for patients and caregivers. Social Security Disability Insurance (SSDI) provides insurance to workers in the United States who have been gainfully employed, but who are no longer able to work due to a medical condition. We performed a descriptive pilot study that examined PD patients' experience with SSDI.

METHODS

PD patients who were diagnosed with PD prior to age 60 and were followed at an academic movement disorders center were consecutively invited to participate in a survey concerning their employment history and experience with SSDI.

RESULTS

All 68 invited patients participated in the study (mean age 58 years, mean disease duration 9.5 years). Eighty-two percent of patients felt that they were too disabled to work full time at a mean of 3.4 years after PD diagnosis. Patients applied for SSDI at a mean of 5 years after diagnosis, and two-thirds of PD patients who applied for SSDI obtained it on their first attempt. The primary debilitating symptom that subjectively contributed to work disability was fatigue (49% of patients). Patients who successfully acquired SSDI had extensive documentation of physician visits, and the aid of a disability lawyer.

CONCLUSIONS

Patients felt they were too disabled to work full time at a mean of 3.4 years after diagnosis. Those who applied for SSDI did so at a mean of 5 years after diagnosis. Patients who obtained SSDI awards had extensive documentation of medical records or the help of a disability lawyer.

Randomized trial of the triple monoamine reuptake inhibitor NS 2330 (tesofensine) in early Parkinson's disease

The objective of this study was to evaluate the efficacy and safety of three daily dosages of the triple monoamine reuptake inhibitor NS 2330 (tesofensine) compared to placebo as monotherapy in early Parkinson's disease (PD). In MPTP (1-methyl 4-phenyl-tetrahydropyridine 1,2,3,6)-lesioned marmosets, dopamine reuptake inhibitors have been demonstrated to reverse parkinsonian signs without evoking established dyskinesia. NS 2330 inhibits reuptake of dopamine, serotonin, and norepinephrine. We performed a proof-of-concept, randomized, double-blind trial of NS 2330. Two hundred sixty-one subjects with PD < 5 years and not receiving dopaminergic treatment were randomly assigned to daily treatment with NS 2330 at 0.25 mg, 0.5 mg, 1.0 mg, or placebo. Adjusted mean difference in total Unified Parkinson's Disease Rating Scale (UPDRS) scores from baseline to week 14 was -0.7 (P = 0.64) in the 0.25-mg group, -1.3 (P = 0.41) in the 0.5-mg group, and -1.7 (P = 0.27) in the 1.0-mg group. The adjusted mean difference in total UPDRS score for the highest dose group (1.0 mg/day) was superior to placebo at week 6 (-3.1; P = 0.02), but this effect was not sustained. NS 2330 was generally well tolerated and the most commonly reported adverse events were constipation, insomnia, and dry mouth. Decreased body weight and elevated heart rate were common in the 1.0-mg dosage group. At the dosages tested, NS 2330 did not provide significantly greater benefit than placebo. It is possible that inhibition of dopamine reuptake alone does not provide clinical benefit in early PD, adequate inhibition of dopamine reuptake was not achieved in this study, or countervailing physiologic mechanisms offset the potential benefit.

Advances in the Pharmacologic Management of Early Parkinson Disease

BACKGROUND

Levodopa, in combination with a dopa decarboxylase inhibitor, provides the greatest symptomatic benefit with the fewest short-term side effects in the treatment of Parkinson disease (PD). However, the disease continues to progress, and the long-term use of levodopa is associated with the development of motor fluctuations and dyskinesias.

REVIEW SUMMARY

Alternatives to the use of levodopa in early PD include monoamine oxidase B (MAO-B) inhibitors, dopamine agonists, and amantadine. Although no medication has been proven to slow the progression of Parkinson disease, preclinical studies have demonstrated neuroprotective effects of MAO-B inhibitors, and a recent study of rasagiline found that PD patients treated with rasagiline for 12 months experienced less progression of symptoms than patients treated with placebo for 6 months followed by rasagiline for 6 months. Several clinical trials have demonstrated that the initial use of a dopamine agonist to which levodopa can be added is associated with fewer motor complications than treatment with levodopa alone. In addition, preclinical studies suggest that adjunctive use of the catechol-O-methyltransferase (COMT) inhibitor entacapone when levodopa is first introduced may be associated with fewer motor complications than treatment with levodopa alone.

CONCLUSION

Treatment of early PD with an MAO-B inhibitor, dopamine agonist, or amantadine, may provide useful alternatives to treatment with levodopa. Adding entacapone at the initiation of levodopa therapy may reduce the development of motor complications. Long-term studies are required to evaluate the potential long-term benefits of these treatment strategies.

Duodenal levodopa infusion for the treatment of Parkinson’s disease

Motor fluctuations are a common problem in the long-term management of Parkinson's disease (PD), resulting in disability and impaired quality of life. The relatively short serum half-life (approximately 90 min) of oral levodopa/carbidopa and its erratic absorption due to delayed and inconsistent gastric emptying (a non-motor feature of PD) are thought to be important factors in the development of motor fluctuations. Continuous infusion of levodopa/carbidopa directly into the small intestine of PD patients results in marked reduction of motor fluctuations by reducing plasma levodopa variability by an order of magnitude over oral therapy. Previously, the use of long-term intraduodenal infusion of levodopa/carbidopa was limited by the relatively large volumes of infusate necessitated by the low solvency of levodopa. The development of a micronized levodopa (20 mg/ml) and carbidopa (5 mg/ml) suspension utilizing a methylcellulose gel provides the high levodopa concentration and physical and chemical stability necessary for long-term enteral therapy. Clinical evidence indicates that a marked reduction of motor fluctuations and dyskinesias can be achieved and maintained by intraduodenal administration of this suspension. This article reviews the published data describing the efficacy and safety of duodenal levodopa, and discusses its current and potential role in meeting the needs of PD patients.

A double-blind placebo-controlled trial of zonisamide (zonegran) in the treatment of essential tremor

Medical therapy for essential tremor (ET), a common movement disorder, is often inadequate. We performed a double-blind placebo-controlled randomized trial to evaluate the efficacy and tolerability of zonisamide (ZNS), an antiepileptic agent, in treating ET. Twenty patients (mean age, 60 +/- 15 years) with ET were randomized to receive ZNS or placebo. ZNS was initiated at a dosage of 100 mg/day and escalated to 200 mg/day at day 14. Patients were evaluated by accelerometry and the Fahn-Tolosa-Marin (FTM) rating scale at baseline and days 14 and 28, as well as the Clinical Global Impression (CGI-C) scale at day 28. At endpoint, subjects assigned to ZNS were taking a mean dosage of 160 +/- 50 mg/day. There were no significant improvements in the FTM total score or its subsections. Tremor amplitude as assessed by accelerometry significantly improved in the ZNS group compared to the placebo group at endpoint relative to baseline (-0.50 +/- 0.72 vs. 0.30 +/- 0.79 m/s(2); P = 0.03). On the CGI-C, 60% (n = 6) of patients in the ZNS group felt that their tremor was unchanged, while the remaining patients felt that their tremor was "minimally improved." Thirty percent (n = 3) of patients taking ZNS discontinued the study due to side effects (fatigue, headache, paresthesias) while taking 100 mg per day. ZNS did not provide significant improvements in clinical rating scales at study endpoint compared to placebo and was only modestly well tolerated. ZNS was effective in reducing tremor amplitude as measured by accelerometry.

Pregabalin (Lyrica) in the treatment of essential tremor

We report on 2 essential tremor patients who experienced marked improvement in upper extremity tremor with the use of pregabalin (Lyrica, PGB). On PGB 200 mg/day, tremor amplitude was reduced by at least 40% in the worst affected hand in both patients as measured by accelerometry. Both patients also reported moderate reduction in tremor on the Clinical Global Impression Scale, and Fahn-Tolosa-Marin Part I scores were markedly improved.

Factors Associated With the Development of Motor Fluctuations and Dyskinesias in Parkinson Disease

BACKGROUND

Motor fluctuations and dyskinesias can cause disability and reduce quality of life for patients with Parkinson disease (PD).

OBJECTIVES

To evaluate factors associated with the development of motor fluctuations and dyskinesias and to assess the sequence in which they occur in individual patients.

DESIGN

We performed a retrospective analysis of data from a randomized clinical trial comparing pramipexole dihydrochloride and levodopa as initial treatment for PD. Subjects were followed up for 48 to 58 months and evaluated at 3-month intervals for the presence of motor fluctuations and dyskinesias.

SETTING

Academic and private practices. Patients Three hundred one patients with early Parkinson disease were enrolled in this study between October 2, 1996, and August 21, 1997, and were observed through August 24, 2001, when the last patient enrolled completed 4 years of follow-up.

MAIN OUTCOME MEASURES

Order of appearance of motor fluctuations and dyskinesias, time to the first occurrence of motor fluctuations, and time to the first occurrence of dyskinesias.

RESULTS

One hundred eighty-nine subjects (62.8%) developed motor complications. Of these, 71 (37.6%) developed fluctuations but not dyskinesias, 23 (12.2%) developed dyskinesias but not fluctuations, 48 (25.4%) developed fluctuations before dyskinesias, 33 (17.5%) developed dyskinesias before fluctuations, and 14 (7.4%) developed both at the same time. Factors significantly associated with earlier occurrence of dyskinesia were Hoehn and Yahr stage of 2 or higher, cumulative levodopa dose, cumulative levodopa equivalent dose (levodopa plus pramipexole), and occurrence of motor fluctuations. Pramipexole treatment was associated with later occurrence of dyskinesias. Factors associated with earlier occurrence of motor fluctuations were cumulative levodopa dose, cumulative levodopa equivalent dose, and occurrence of dyskinesias. Factors associated with later occurrence of motor fluctuations were age at onset of 65 years or older and pramipexole treatment.

CONCLUSIONS

Higher cumulative levodopa doses and higher cumulative levodopa equivalent doses (levodopa plus pramipexole) were associated with the earlier occurrence of motor complications. Motor fluctuations and dyskinesias appear to be interrelated because the presence of one is associated with the earlier development of the other.