The Quebec Parkinson Network: A Researcher-Patient Matching Platform and Multimodal Biorepository.

BACKGROUND: Genetic, biologic and clinical data suggest that Parkinson's disease (PD) is an umbrella for multiple disorders with clinical and pathological overlap, yet with different underlying mechanisms. To better understand these and to move towards neuroprotective treatment, we have established the Quebec Parkinson Network (QPN), an open-access patient registry, and data and bio-samples repository. OBJECTIVE: To present the QPN and to perform preliminary analysis of the QPN data. METHODS: A total of 1,070 consecutively recruited PD patients were included in the analysis. Demographic and clinical data were analyzed, including comparisons between males and females, PD patients with and without RBD, and stratified analyses comparing early and late-onset PD and different age groups. RESULTS: QPN patients exhibit a male:female ratio of 1.8:1, an average age-at-onset of 58.6 years, an age-at-diagnosis of 60.4 years, and average disease duration of 8.9 years. REM-sleep behavior disorder (RBD) was more common among men, and RBD was associated with other motor and non-motor symptoms including dyskinesia, fluctuations, postural hypotension and hallucinations. Older patients had significantly higher rates of constipation and cognitive impairment, and longer disease duration was associated with higher rates of dyskinesia, fluctuations, freezing of gait, falls, hallucinations and cognitive impairment. Since QPN's creation, over 60 studies and 30 publications have included patients and data from the QPN. CONCLUSIONS: The QPN cohort displays typical PD demographics and clinical features. These data are open-access upon application (http://rpq-qpn.ca/en/), and will soon include genetic, imaging and bio-samples. We encourage clinicians and researchers to perform studies using these resources.

Safety and efficacy of CVT-301 (levodopa inhalation powder) on motor function during off periods in patients with Parkinson's disease: a randomised, double-blind, placebo-controlled phase 3 trial.

BACKGROUND: Patients with Parkinson's disease chronically treated with levodopa commonly have delayed or unpredictable onset of its benefits after oral intake. In this study, we assessed the safety and efficacy of CVT-301, a self-administered levodopa oral inhalation powder, for the treatment of patients with Parkinson's disease during off periods. METHODS: In this randomised, double-blind, placebo-controlled, phase 3 trial, patients were recruited at 65 sites in Canada, Poland, Spain, and the USA. Eligible participants were patients with Parkinson's disease aged 30-85 years, who had daily off periods of 2 h or longer and showed an improvement of 25% or greater in the Unified Parkinson's Disease Rating Scale (UPDRS) motor score from off to on state after use of an oral levodopa plus a dopa-decarboxylase inhibitor combination. Patients were assigned (1:1:1) with a computer-generated randomisation code, in fixed blocks of six, to either CVT-301 60 mg, CVT-301 84 mg, or placebo. Spirometry results and modified Hoehn and Yahr disease stage at screening were used for stratification of treatment groups. Patients, the sponsor, and site personnel were masked to treatment assignment. Each study dose consisted of two capsules administered with an inhaler. Patients were instructed to use the study drug as needed for off periods, and could self-administer up to five doses per day. The primary endpoint was the change in UPDRS motor score from predose to 30 min postdose, assessed at week 12 during an in-clinic off period, in the CVT-301 84 mg group compared with the placebo group. Analysis was by intention to treat. Safety was assessed in all patients who received at least one dose of experimental treatment. This trial is registered with ClinicalTrials.gov, number NCT02240030. FINDINGS: Between Dec 4, 2014, and Aug 26, 2016, 351 patients were enrolled and randomly assigned to receive CVT-301 60 mg (115 patients), CVT-301 84 mg (120 patients), or placebo (116 patients). Of these, 339 received the assigned study treatment (CVT-301 60 mg, n=113; CVT-301 84 mg, n=114; placebo, n=112) and 290 completed the study (CVT-301 60 mg, n=96; CVT-301 84 mg, n=97; placebo, n=97). The least-squares mean difference in UPDRS motor score change from predose to 30 min postdose was -5·91 (SE 1·50, 95% CI -8·86 to -2·96) for the placebo group and -9·83 (1·51; -12·79 to -6·87) for the CVT-301 84 mg group (between-group difference -3·92 [-6·84 to -1·00]; p=0·0088). Treatments were safe and well tolerated. Severe adverse events were reported by 2 (2%) of 112 patients in the placebo group, 7 (6%) of 113 in the CVT-301 60 mg group, and 5 (4%) of 114 in the CVT-301 84 mg group, with no severe adverse event occurring in more than one patient in any treatment group. 11 (3%) of 339 patients had 19 serious adverse events (three [3%] of 112 patients in placebo, six [5%] of 113 in CVT-301 60 mg, and two [2%] of 114 in CVT-301 84 mg). Of these, hypotension and atrial fibrillation were assessed by investigators to be possibly related to the study drug. INTERPRETATION: CVT-301 can improve UPDRS motor scores of patients with Parkinson's disease during in-clinic off periods, with few severe or serious adverse events. The long-term safety and efficacy of CVT-301 need to be investigated in future studies. FUNDING: Acorda Therapeutics.

A Randomized Trial of Oral and Transdermal Rivastigmine for Postural Instability in Parkinson Disease Dementia.

OBJECTIVES: The objective of this study was to compare the efficacy and safety of oral and transdermal rivastigmine for postural instability in patients with Parkinson disease dementia (PDD) who were candidates for a cholinesterase inhibitor. The primary outcome was the change in mean velocity of the center of pressure (CoP) after 6 months. Secondary outcomes included structural parameters of dynamic posturography, clinical rating scales, and adverse events requiring dose reduction. METHODS: Patients with PDD were randomized in a 1:1 ratio to oral or transdermal rivastigmine with target doses of 6 mg twice daily and 9.5 mg/10 cm daily, respectively. Outcomes were assessed at baseline and 6 months. Results were compared within and between groups. RESULTS: Nineteen patients completed the study (n = 8 oral, n = 11 transdermal). Mean daily doses of 9.4 (±1.5 mg) and 16.4 (±3.6 mg) were achieved in the oral and transdermal groups, respectively. The transdermal group demonstrated a significant 15.8% decrease in mean velocity of CoP (patch: P < 0.05; oral: 10.0% decrease, P = 0.16) in the most difficult scenario (eyes closed with sway-referenced support). There was no difference between groups (P = 0.27). For structural parameters, significant improvements were seen in the mean duration of peaks (patch) and interpeak distance (oral) in the most difficult condition. No changes were observed in clinical rating scales. Six patients experienced nonserious adverse events requiring dose reduction (n = 5 oral; n = 1 transdermal). CONCLUSIONS: Rivastigmine may improve certain elements of postural control, notably the mean velocity of CoP. Benefits appear to be more obvious under more taxing sensory conditions.

Adenosine 2A Receptor Antagonists for the Treatment of Motor Symptoms in Parkinson's Disease.

BACKGROUND: Treatment of motor fluctuations in Parkinson's disease (PD) remains an unmet challenge. Adenosine 2A (A2A) receptors are located along the indirect pathway and represent a potential target to enhance l-3,4-dihydroxyphenylalanine (l-DOPA) antiparkinsonian action. METHODS: This article summarizes the preclinical and clinical literature on A2A antagonists in PD, with a specific focus on their effect on off time, on time, and dyskinesia. FINDINGS: Several A2A receptor antagonists have been tested in preclinical studies and clinical trials. In preclinical studies, A2A antagonists enhanced l-DOPA antiparkinsonian action without exacerbating dyskinesia, but A2A antagonists were generally administered in combination with a subthreshold dose of l-DOPA, which is different to the paradigms used in clinical trials, where A2A antagonists were usually added to an optimal antiparkinsonian regimen. In clinical settings, A2A antagonists generally reduced duration of off time, by as much as 25% in some studies. The effect of on time duration is less clear, and in a few studies an exacerbation of dyskinesia was reported. Two A2A antagonists have been tested in phase III settings: istradefylline and preladenant. Istradefylline was effective in two phase III trials, but ineffective in another; the drug has been commercially available in Japan since 2013. In contrast, preladenant was ineffective in a phase III trial and the drug was discontinued. A phase III study with tozadenant will begin in 2015; the drug was effective at reducing off time in a phase IIb study. Other A2A antagonists are in development at the preclinical and early clinical levels.

Tozadenant (SYN115) in patients with Parkinson's disease who have motor fluctuations on levodopa: a phase 2b, double-blind, randomised trial.

BACKGROUND: Many patients with Parkinson's disease have motor fluctuations despite treatment with available drugs. Tozadenant (SYN115) is an oral, selective adenosine A2A receptor antagonist that improves motor function in animal models of Parkinson's disease. We aimed to assess the safety and efficacy of tozadenant as an adjunct to levodopa in patients with Parkinson's disease who have motor fluctuations on levodopa. METHODS: We did an international, multicentre, phase 2b, randomised, double-blind, placebo-controlled, parallel-group, dose-finding clinical trial of tozadenant in levodopa-treated patients with Parkinson's disease who had motor fluctuations (at least 2·5 h off-time per day). Eligible patients were randomly assigned via a computer-generated randomisation schedule to receive tozadenant 60, 120, 180, or 240 mg or matching placebo twice daily for 12 weeks. All study management, site personnel, and patients were masked to treatment assignment. The primary outcome was change from baseline to week 12 in hours per day spent in the off-state (assessed from Parkinson's disease diaries completed by patients). This study is registered at ClinicalTrials.gov, number NCT01283594. FINDINGS: Of 420 randomised patients (mean age 63·3 [SD 8·3] years; mean duration of Parkinson's disease 8·7 [4·7] years), 403 provided post-baseline diary data and 337 completed study treatment. Compared with placebo, mean daily off-time was significantly reduced in the combined tozadenant 120 mg twice-daily and 180 mg twice-daily group (-1·1 h, 95% CI -1·8 to -0·5; p=0·0006), the tozadenant 120 mg twice-daily group (-1·1 h, -1·8 to -0·4; p=0.0039), and the tozadenant 180 mg twice-daily group (-1·2 h, -1·9 to -0·4; p=0·0039). The most common adverse events in these groups were dyskinesia (seven [8%] of 84 patients in the placebo group, 13 [16%] of 82 in the 120 mg twice-daily group, and 17 [20%] of 85 in the 180 mg twice-daily group), nausea (three [4%], 9 [11%], and ten [12%]), and dizziness (one [1%], four [5%], and 11 [13%]). Tozadenant 60 mg twice daily was not associated with a significant reduction in off-time, and tozadenant 240 mg twice daily was associated with an increased rate of discontinuation because of adverse events (17 [20%] of 84 patients). INTERPRETATION: Tozadenant at 120 or 180 mg twice daily was generally well tolerated and was effective at reducing off-time. Further investigation of tozadenant treatment in phase 3 trials is warranted. FUNDING: Biotie Therapies.

A randomized clinical trial of high-dosage coenzyme Q10 in early Parkinson disease: no evidence of benefit.

IMPORTANCE: Coenzyme Q10 (CoQ10), an antioxidant that supports mitochondrial function, has been shown in preclinical Parkinson disease (PD) models to reduce the loss of dopamine neurons, and was safe and well tolerated in early-phase human studies. A previous phase II study suggested possible clinical benefit. OBJECTIVE: To examine whether CoQ10 could slow disease progression in early PD. DESIGN, SETTING, AND PARTICIPANTS: A phase III randomized, placebo-controlled, double-blind clinical trial at 67 North American sites consisting of participants 30 years of age or older who received a diagnosis of PD within 5 years and who had the following inclusion criteria: the presence of a rest tremor, bradykinesia, and rigidity; a modified Hoehn and Yahr stage of 2.5 or less; and no anticipated need for dopaminergic therapy within 3 months. Exclusion criteria included the use of any PD medication within 60 days, the use of any symptomatic PD medication for more than 90 days, atypical or drug-induced parkinsonism, a Unified Parkinson's Disease Rating Scale (UPDRS) rest tremor score of 3 or greater for any limb, a Mini-Mental State Examination score of 25 or less, a history of stroke, the use of certain supplements, and substantial recent exposure to CoQ10. Of 696 participants screened, 78 were found to be ineligible, and 18 declined participation. INTERVENTIONS: The remaining 600 participants were randomly assigned to receive placebo, 1200 mg/d of CoQ10, or 2400 mg/d of CoQ10; all participants received 1200 IU/d of vitamin E. MAIN OUTCOMES AND MEASURES: Participants were observed for 16 months or until a disability requiring dopaminergic treatment. The prospectively defined primary outcome measure was the change in total UPDRS score (Parts I-III) from baseline to final visit. The study was powered to detect a 3-point difference between an active treatment and placebo. RESULTS: The baseline characteristics of the participants were well balanced, the mean age was 62.5 years, 66% of participants were male, and the mean baseline total UPDRS score was 22.7. A total of 267 participants required treatment (94 received placebo, 87 received 1200 mg/d of CoQ10, and 86 received 2400 mg/d of CoQ10), and 65 participants (29 who received placebo, 19 who received 1200 mg/d of CoQ10, and 17 who received 2400 mg/d of CoQ10) withdrew prematurely. Treatments were well tolerated with no safety concerns. The study was terminated after a prespecified futility criterion was reached. At study termination, both active treatment groups showed slight adverse trends relative to placebo. Adjusted mean changes (worsening) in total UPDRS scores from baseline to final visit were 6.9 points (placebo), 7.5 points (1200 mg/d of CoQ10; P = .49 relative to placebo), and 8.0 points (2400 mg/d of CoQ10; P = .21 relative to placebo). CONCLUSIONS AND RELEVANCE: Coenzyme Q10 was safe and well tolerated in this population, but showed no evidence of clinical benefit. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00740714.

Long-term safety of rivastigmine in parkinson disease dementia: an open-label, randomized study.

OBJECTIVE: This study investigated the long-term safety of rivastigmine (12 mg/d capsules, 9.5 mg/24 h patch) and effects on motor symptoms in patients with mild-to-moderately severe Parkinson disease dementia. METHODS: This was a 76-week, prospective, open-label, randomized study in patients aged 50 to 85 years. Primary outcomes included incidence of, and discontinuation due to, predefined adverse events (AEs) potentially arising from worsening of Parkinson disease motor symptoms with capsules. Secondary outcomes included frequency of AEs/serious AEs. Efficacy outcomes included Alzheimer's Disease Cooperative Study-Activities of Daily Living (ADCS-ADL), Neuropsychiatric Inventory (NPI-10), and Mattis Dementia Rating Scale (MDRS). RESULTS: Five hundred eighty-three patients were randomized to rivastigmine capsules (n = 295) or patch (n = 288). Incidence of predefined AEs was 36.1% for capsules, 31.9% for patch; discontinuation due to worsening of motor symptoms was 4.4% and 2.4%, respectively. Most common AEs were nausea (capsules, 40.5%; patch, 8.3%), tremor (24.5%; 9.7%), fall (17.0%; 20.1%), vomiting (15.3%; 2.8%), and application site erythema (0%; 13.9%). Significant efficacy in favor of capsules was observed at weeks 24 to 76 on MDRS; 24 and 76 on NPI-10; weeks 52 and 76 on ADCS-ADL. In patients with Mini-Mental State Examination (MMSE) greater than 21, no differences in efficacy on MDRS and ADCS-ADL were observed at any time point; significant differences in favor of capsules were maintained in patients with MMSE less than or equal to 21. CONCLUSIONS: This study supports the long-term safety of rivastigmine in Parkinson disease dementia. The rate of worsening of motor symptoms was in the range expected due to the natural progression of Parkinson disease, no new or unexpected safety issues emerged in the long-term.

Effects of 24 wk of treadmill training on gait performance in Parkinson's disease.

PURPOSE: Recent studies suggest that walking on a treadmill improves gait, mobility, and quality of life of patients with Parkinson's disease (PD). Still, there is a need for larger-scale randomized controlled studies that demonstrate the advantages of treadmill training (TT) with control groups that receive similar amounts of attention. Moreover, to date, no study has combined speed and incline as parameters of progression. The aim of the study was to evaluate the effects of 24 wk of TT, with and without the use of incline, on gait, mobility and quality of life in patients with PD. METHODS: The sample comprised 34 patients with PD, at the Hoehn and Yahr stage 1.5 or 2. Participants were randomized to speed TT, mixed TT, and control groups. The intervention consisted of 72 one-hour exercise sessions for 24 wk. The main outcome measures are the Movement Disorder Society-Unified Parkinson's Disease Rating Scale, the 39-item Parkinson's Disease Questionnaire, spatiotemporal parameters of gait and 6-min walking distance. The measures were taken at baseline, mid-term and after 6 months. RESULTS: Both TT groups improved in terms of speed, cadence, and stride length during self-selected walking conditions at the study end point. Both groups also showed improvements in distance traveled. Only the Mixed TT group improved their quality of life. The Control group showed no progress. CONCLUSIONS: Participants in this study showed significant improvements in walking speed and walking endurance after 6 months of TT. Improvements were observed after 3 months of intensive TT and persisted at 6 months. It appears that individuals with poorer baseline performance may benefit most from TT.

Randomized trial of IPX066, carbidopa/levodopa extended release, in early Parkinson's disease.

OBJECTIVE: IPX066 is an extended release carbidopa/levodopa formulation designed to rapidly attain and maintain therapeutic plasma concentrations for a prolonged duration, allowing dosing intervals of approximately 6 h. The objective was to assess the efficacy, safety, and impact on quality of life of IPX066 in the treatment of levodopa-naive Parkinson's disease (PD) patients. METHODS: This was a randomized, double-blind, placebo-controlled, 30-week study of 381 levodopa-naïve patients assigned to placebo or IPX066 containing 145, 245 or 390 mg of levodopa administered three times daily (TID). The primary efficacy measure was change from Baseline in Unified Parkinson's Disease Rating Scale (UPDRS) activities of daily living (Part II) + motor scores (Part III), at 30 weeks. Secondary outcome measures included UPDRS total and subscores, patient and clinician global impressions (PGI-I, CGI-I), and the Parkinson's Disease Questionnaire (PDQ-39). RESULTS: All IPX066 dosages were superior to placebo throughout the study and at 30 weeks (P < 0.0001). The mean improvement in UPDRS Parts II + III at 30 weeks compared to baseline was 11.7, 12.9, and 14.9 points for the three dosages and 0.6 points for placebo (P < 0.0001, all dosages). PDQ-39 total scores improved with IPX066 (P ≤ 0.034, all dosages). The most commonly reported adverse events with IPX066 included nausea, dizziness, and headache. No unexpected drug-related serious adverse events were reported. CONCLUSION: IPX066 provided significant clinical benefits at the three dosages tested compared to placebo and was well tolerated in levodopa-naive PD patients. Of the dosages tested, IPX066 145 mg TID appeared to provide the best overall balance between efficacy and safety.

Long-term safety and efficacy of preladenant in subjects with fluctuating Parkinson's disease.

BACKGROUND: Preladenant is a selective adenosine A2A receptor antagonist under investigation for Parkinson's disease treatment. METHODS: A phase 2 36-week open-label follow-up of a double-blind study using preladenant 5 mg twice a day as a levodopa adjunct in 140 subjects with fluctuating Parkinson's disease was conducted. The primary end point was adverse event (AE) assessment. Secondary (efficacy) analyses included hours/day spent in OFF and ON states and dyskinesia prevalence/severity. RESULTS: The 36-week open-label phase was completed by 106 of 140 subjects (76%). AE-related treatment discontinuations occurred in 19 subjects (14%). Treatment-emergent AEs, reported by ≥15% of subjects, were dyskinesia (33%) and constipation (19%). Preladenant 5 mg twice a day provided OFF time reductions (1.4-1.9 hours/day) and ON time increases (1.2-1.5 hours/day) throughout the 36-week treatment relative to the baseline of the double-blind study. CONCLUSIONS: Long-term preladenant treatment (5 mg twice a day) was generally well tolerated and provided sustained OFF time reductions and ON time increases.

Investigation of C9orf72 repeat expansions in Parkinson's disease.

Large repeat expansions in the C9orf72 gene were recently reported to be a major cause of familial amyotrophic lateral sclerosis and frontotemporal dementia. Given some of the clinical and pathologic overlap between these 2 diseases and Parkinson's disease, we sought to evaluate the presence of these expansions in a cohort of French-Canadian patients with Parkinson's disease. No pathologic expansion was found in our cohort of patients suggesting that C9orf72 repeat expansions do not play a major role in the pathogenesis of Parkinson's disease.

Donepezil in Parkinson's disease dementia: a randomized, double-blind efficacy and safety study.

Parkinson's disease dementia (PDD) is associated with cholinergic deficits. This report presents an efficacy and safety study of the acetylcholinesterase inhibitor donepezil hydrochloride in PDD. PDD patients (n = 550) were randomized to donepezil (5 or 10 mg) or placebo for 24 weeks. Coprimary end points were the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog) and Clinician's Interview-Based Impression of Change plus caregiver input (CIBIC+; global function). Secondary end points measured executive function, attention, activities of daily living (ADLs), and behavioral symptoms. Safety and tolerability were assessed. ADAS-cog mean changes from baseline to week 24 (end point) were not significant for donepezil in the intent-to-treat population by the predefined statistical model (difference from placebo: -1.45, P = .050, for 5 mg; -1.45, P = .076, for 10 mg). Alternative ADAS-cog analysis, removing the treatment-by-country interaction term from the model, revealed significant, dose-dependent benefit with donepezil (difference from placebo: -2.08, P = .002, for 5 mg; -3.31, P < .001, for 10 mg). The 10-mg group, but not the 5-mg group, had significantly better CIBIC+ scores compared with placebo (3.7 vs 3.9, P = .113, for 5 mg; 3.6 vs 3.9, P = .040, for 10 mg). Secondary end points-Mini-Mental State Exam; Delis-Kaplan Executive Function System; Brief Test of Attention, representing cognitive functions particularly relevant to PDD-showed significant benefit for both donepezil doses (P ≤ .007). There were no significant differences in ADLs or behavior. Adverse events were more common with donepezil but mostly mild/moderate in severity. Although the study did not achieve its predefined primary end points, it presents evidence suggesting that donepezil can improve cognition, executive function, and global status in PDD. Tolerability was consistent with the known safety profile of donepezil. © 2012 Movement Disorder Society.

Influence of risperidone on balance control in young healthy individuals.

RATIONALE: It has previously been shown that impairment of postural stability is a side effect of typical antipsychotic drugs, which are largely administered to control psychosis and behavioral symptoms in elderly patients. Surprisingly, no study has yet addressed this problem with second-generation antipsychotics. OBJECTIVE: The objective of this study was to determine the extent to which risperidone at low doses altered balance control in healthy participants. METHODS: Twelve healthy young adults received, following a randomized double-blind crossover design, a single oral dose of placebo, 1 and 3 mg of risperidone on separate days at least 14 days apart. Evaluation of extrapyramidal symptoms using the Extrapyramidal Symptom Rating Scale-abbreviated scoring form (ESRS-A) and measures of postural sway using a force platform were assessed over 9 h following drug ingestion. RESULTS: There is a significant increase in the postural stability item of the ESRS-A parkinsonism subscale at 3 and 6 h following 3 mg of risperidone only when compared to placebo. With regard to balance control, body sway measures were increased at 1 mg of risperidone but more pronounced at 3 mg. The peak effects were observed at 3 h after administration of the drug and had not completely returned to baseline after 9 h. CONCLUSIONS: Risperidone administered at low doses did not elicit clinically detectable EPS but had significant effects on balance control. A dose-response effect on impairment of balance was observed that followed the expected time course of the drug pharmacokinetics. These results are likely to apply to older or demented individuals who have pre-existing balance control deficit.

Istradefylline for Parkinson's disease patients experiencing motor fluctuations: results of the KW-6002-US-018 study.

BACKGROUND: Istradefylline (KW-6002) is a selective adenosine A(2A) receptor antagonist investigated as adjunctive therapy to levodopa in PD patients with motor response complications. In Phase 2b/3 studies, Istradefylline reduced OFF time without worsening troublesome dyskinesia and was well tolerated. METHODS: A randomized, 12-week, double-blind, placebo-controlled parallel-group study evaluated the efficacy of 10, 20, and 40 mg/day of Istradefylline in patients on levodopa therapy with motor response complications. The primary outcome measure was change from baseline to endpoint in the percentage of awake time/day spent in the OFF state as determined by patient diary. RESULTS: Six hundred and ten patients were randomized. Five hundred and eighty four patients were included in the Intent-to-treat (ITT) group-146 placebo patients and 149 in the 10 mg, 144 in the 20, and 145 patients in the 40 mg Istradefylline groups. Baseline demographics were similar between groups. Treatment cohorts had been diagnosed an average of 9 years diagnosis and 3.6 years from the onset of motor fluctuations; at baseline they had an average of 6.7 h of OFF time and an average UPDRS motor score of 22 when ON. At endpoint, the amount and percentage of OFF time did not differ between Istradefylline and placebo, however a dose-ordering response was observed. Changes from baseline in the UPDRS motor score in the on state for the 40 mg were modest but significant compared to placebo (2.9 vs. 0.8; p < 0.05). CONCLUSIONS: Although Istradefylline did not impact OFF time duration, it significantly improved motor score at 40 mg/day.

Serotonin and dopamine striatal innervation in Parkinson's disease and Huntington's chorea.

In contrast to our vast knowledge of the dopamine (DA) system, much less is known about the involvement of serotonin (5-HT) in neurodegenerative diseases affecting the basal ganglia. Therefore, we designed a study that aimed at characterizing the status of the striatal DA and 5-HT systems in patients who suffered from either Parkinson's (PD) or Huntington's disease (HD), compared to age-matched controls. Antibodies against tyrosine hydroxylase (TH) and 5-HT transporter (SERT) were used as markers of DA and 5-HT axonal profiles, respectively. The density and pattern of TH+ and SERT + innervation were determined by optical density measurements as well as by direct stereological estimates of labeled axon varicosities. The results reveal a significant decrease in TH immunoreactivity and TH + axon terminals throughout the striatum in both PD and HD, whereas the intensity of SERT immunostaining and the density of SERT + axon varicosities were found to be slightly increased in the striatum of PD and HD patients compared to controls. These findings reveal that the nigrostriatal DA system is significantly impaired in both PD and HD compared to the striatal 5-HT innervation, which is slightly increased in these two conditions. The striatal 5-HT augmentation observed in PD might be the result of a neural mechanism designed to compensate for DA denervation, whereas the marked atrophy of the striatum might explain the increase in the 5-HT innervation noted in HD. These findings underline the importance of the complex interplay between DA and 5-HT striatal afferents in the elaboration of appropriate motor behaviour.

Balance control improves following replacement of paroxetine with venlafaxine and levodopa in a case of microvascular dementia.

BACKGROUND: Postural instability is a concern in several neurologic conditions and also among the elderly. Dysfunction in serotonergic, noradrenergic, and dopaminergic pathways may be involved in the etiology of postural imbalance. OBJECTIVE: The objective of this case report was to quantify, using computerized posturography, substitution with venlafaxine, and later levodopa, in a suspected case of postural instability with paroxetine. CASE SUMMARY: Presented is an 86-year-old woman with frequent falls and a Parkinson-like syndrome of the lower limbs secondary to microvascular dementia. Paroxetine was gradually discontinued and exchanged for venlafaxine, 37.5 mg twice daily. Before and after medication changes, static posturography was performed under eyes open and closed conditions. Following 3 months of venlafaxine, the patient showed significant improvement from baseline, however, venlafaxine was then reduced to 37.5 mg at bedtime. Six months later, levodopa was introduced and further improvement was observed. It is possible that venlafaxine, which maintains a more balanced affinity for serotonin and norepinephrine transporters, may have provided postural benefit. Decreased sedation secondary to venlafaxine reduction may have elicited further improvements in addition to the increased lower limb functionality observed with levodopa. CONCLUSIONS: For patients on antidepressants, switching medications may be worthwhile in those with balance problems. The prudent addition of medications may also be an option.

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.

Intense dopamine innervation of the subventricular zone in Huntington's disease.

Dopamine exerts a robust promoting effect on adult neurogenesis. Here, we report the presence of an intense dopamine (tyrosine hydroxylase immunoreactive) zone along the ventricular border of the caudate nucleus in patients with Huntington's disease, but not in age-matched controls. This thin (150-400 microm) paraventricular zone was composed of numerous small and densely packed dopamine axon varicosities and overlapped the deep layers of the subventricular zone. Immunoreactivity in the paraventricular zone was 50% higher than in adjacent striatal areas. This intense dopamine zone concurs with the striking increase of neurogenesis noted in the subventricular zone of Huntington's disease patients and indicates that dopamine might play a crucial role in intrinsic mechanisms designed to compensate for the massive striatal neuronal losses that occur in Huntington's disease.