[Show abstract][Hide abstract] ABSTRACT: IMPORTANCE Convergent biological, epidemiological, and clinical data identified urate elevation as a candidate strategy for slowing disability progression in Parkinson disease (PD). OBJECTIVE To determine the safety, tolerability, and urate-elevating capability of the urate precursor inosine in early PD and to assess its suitability and potential design features for a disease-modification trial. DESIGN, SETTING, AND PARTICIPANTS The Safety of Urate Elevation in PD (SURE-PD) study, a randomized, double-blind, placebo-controlled, dose-ranging trial of inosine, enrolled participants from 2009 to 2011 and followed them for up to 25 months at outpatient visits to 17 credentialed clinical study sites of the Parkinson Study Group across the United States. Seventy-five consenting adults (mean age, 62 years; 55% women) with early PD not yet requiring symptomatic treatment and a serum urate concentration less than 6 mg/dL (the approximate population median) were enrolled. INTERVENTIONS Participants were randomized to 1 of 3 treatment arms: placebo or inosine titrated to produce mild (6.1-7.0 mg/dL) or moderate (7.1-8.0 mg/dL) serum urate elevation using 500-mg capsules taken orally up to 2 capsules 3 times per day. They were followed for up to 24 months (median, 18 months) while receiving the study drug plus 1 washout month. MAIN OUTCOMES AND MEASURES The prespecified primary outcomes were absence of unacceptable serious adverse events (safety), continued treatment without adverse event requiring dose reduction (tolerability), and elevation of urate assessed serially in serum and once (at 3 months) in cerebrospinal fluid. RESULTS Serious adverse events (17), including infrequent cardiovascular events, occurred at the same or lower rates in the inosine groups relative to placebo. No participant developed gout and 3 receiving inosine developed symptomatic urolithiasis. Treatment was tolerated by 95% of participants at 6 months, and no participant withdrew because of an adverse event. Serum urate rose by 2.3 and 3.0 mg/dL in the 2 inosine groups (P < .001 for each) vs placebo, and cerebrospinal fluid urate level was greater in both inosine groups (P = .006 and <.001, respectively). Secondary analyses demonstrated nonfutility of inosine treatment for slowing disability. CONCLUSIONS AND RELEVANCE Inosine was generally safe, tolerable, and effective in raising serum and cerebrospinal fluid urate levels in early PD. The findings support advancing to more definitive development of inosine as a potential disease-modifying therapy for PD. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00833690.
[Show abstract][Hide abstract] ABSTRACT: IMPORTANCE Understanding the natural history of Huntington disease will inform patients and clinicians on the disease course and researchers on the design of clinical trials. OBJECTIVE To determine the longitudinal change in clinical features among individuals with Huntington disease compared with controls. DESIGN, SETTING, AND PARTICIPANTS Prospective, longitudinal cohort study at 44 research sites in Australia (n = 2), Canada (n = 4), and the United States (n = 38). Three hundred thirty-four individuals with clinically manifest Huntington disease who had at least 3 years of annually accrued longitudinal data and 142 controls consisting of caregivers and spouses who had no genetic risk of Huntington disease. MAIN OUTCOMES AND MEASURES Change in movement, cognition, behavior, and function as measured by the Unified Huntington's Disease Rating Scale, the Mini-Mental State Examination, and vital signs. RESULTS Total motor score worsened by 3.0 points (95% CI, 2.5-3.4) per year and chorea worsened by 0.3 point per year (95% CI, 0.1-0.5). Cognition declined by 0.7 point (95% CI, 0.6-0.8) per year on the Mini-Mental State Examination. Behavior, as measured by the product of frequency and severity score on the Unified Huntington's Disease Rating Scale, worsened by 0.6 point per year (95% CI, 0.0-1.2). Total functional capacity declined by 0.6 point per year (95% CI, 0.5-0.7). Compared with controls, baseline body mass index was lower in those with Huntington disease (25.8 vs 28.8; P < .001), and average pulse was higher (74.2 vs 69.6 beats/min; P < .001). CONCLUSIONS AND RELEVANCE Over 3 years, the cardinal features of Huntington disease all declined in a monotonic manner. These data quantify the natural history of the disease and may inform the design of trials aimed at reducing its burden. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00313495.
[Show abstract][Hide abstract] ABSTRACT: To use optical coherence tomography (OCT) and contrast letter acuity to characterize vision loss in Friedreich ataxia (FRDA). High- and low-contrast letter acuity and neurological measures were assessed in 507 patients with FRDA. In addition, OCT was performed on 63 FRDA patients to evaluate retinal nerve fiber layer (RNFL) and macular thickness. Both OCT and acuity measures were analyzed in relation to genetic severity, neurologic function, and other disease features. High- and low-contrast letter acuity was significantly predicted by age and GAA repeat length, and highly correlated with neurological outcomes. When tested by OCT, 52.7 % of eyes (n = 110) had RNFL thickness values below the fifth percentile for age-matched controls. RNFL thickness was significantly lowest for those with worse scores on the Friedreich ataxia rating scale (FARS), worse performance measure composite Z 2 scores, and lower scores for high- and low-contrast acuity. In linear regression analysis, GAA repeat length and age independently predicted RNFL thickness. In a subcohort of participants, 21 % of eyes from adult subjects (n = 29 eyes) had macular thickness values below the first percentile for age-matched controls, suggesting that macular abnormalities can also be present in FRDA. Low-contrast acuity and RNFL thickness capture visual and neurologic function in FRDA, and reflect genetic severity and disease progression independently. This suggests that such measures are useful markers of neurologic progression in FRDA.
Journal of Neurology 06/2013; · 3.58 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background: Tetrabenazine, a treatment for chorea in Huntington disease, carries a boxed warning due to safety, especially related to suicidality. Objective: To compare the frequency of depressed mood and suicidality among a closely monitored cohort of individuals with Huntington disease who were exposed and not exposed to tetrabenazine. Methods: A longitudinal prospective study involving 1360 individuals with HD evaluated at 48 research centers in Australia, Canada, and the United States was examined for frequency of depressed mood that triggered a risk assessment, suicidal thoughts, suicide attempts, and completed suicide among individuals with prior, new, and no exposure to tetrabenazine.. Seventy-seven individuals were on tetrabenazine at study enrollment (prior exposure), 64 individuals were exposed to tetrabenazine during the study's course (new exposure), and 1219 individuals had no exposure to tetrabenazine. Results: The hazard ratio for depressed mood among those with prior exposure to tetrabenazine compared to no exposure was 0.9 (95% CI, 0.5-1.6) and for those with new exposure compared to no exposure was 1.2 (95% CI, 0.8-1.9). One individual (1.3%) with prior exposure, one individual (1.6%) with new exposure, and 35 individuals (2.9%) with no exposure to tetrabenazine reported suicidal thoughts. The hazard ratio for suicidal ideation among those with prior exposure to tetrabenazine compared to no exposure was 0.5 (95% CI, 0.1-3.8) and for those with new exposure to tetrabenazine compared to no exposure was 0.6 (95% CI, 0.1-4.4). Among individuals with prior or new exposure to tetrabenazine, no suicide attempts or suicides occurred. Among those with no exposure to tetrabenazine 17 suicide attempts (1.4%) and four suicides (0.3%) occurred. Conclusions: In a large observational study with close clinical supervision, tetrabenazine treatment was not associated with an increased risk of depressed mood, suicidal ideation, suicide attempts, or suicide.
Journal of Huntington's disease. 01/2013; 2(4):509-515.
[Show abstract][Hide abstract] ABSTRACT: Friedreich ataxia is an autosomal recessive neurodegenerative disorder characterized by ataxia, dysarthria, and areflexia. The authors report the progress of a large international noninterventional cohort (n = 410), tracking the natural history of disease progression using the neurologic examination-based Friedreich Ataxia Rating Scale. The authors analyzed the rate of progression with cross-sectional analysis and longitudinal analysis over a 2-year period. The Friedreich Ataxia Rating Scale captured disease progression when used at 1 and 2 years following initial evaluation, with a lower ratio of standard deviation of change to mean change over 2 years of evaluation. However, modeling of disease progression identified substantial ceiling effects in the Friedreich Ataxia Rating Scale, suggesting this measure is most useful in subjects before maximal deficit is approached.
Journal of child neurology 06/2012; 27(9):1152-8. · 1.59 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Friedreich ataxia (FA) is the most common ataxia and results from an expanded GAA repeat in the first intron of FXN. This leads to epigenetic modifications and reduced frataxin. We investigated the relationships between genetic, epigenetic, and clinical parameters in a large case-control study of FA.
Clinical data and samples were obtained from individuals with FA during annual visits to our dedicated FA clinic. GAA expansions were evaluated by polymerase chain reaction (PCR) and restriction endonuclease digest. DNA methylation was measured using bisulfite-based EpiTYPER MassARRAY (Sequenom, San Diego, CA). FXN expression was determined using real-time reverse transcriptase PCR. Significant correlations between the different parameters were examined using the nonparametric Spearman rank correlation coefficient, as well as univariate and multivariate regression modeling.
Characteristic DNA methylation was identified upstream and downstream of the expansion, and validated in an independent FA cohort. Univariate and multivariate analyses showed significant inverse correlations between upstream methylation and FXN expression, and variation in downstream methylation and age of onset. FXN expression also inversely correlated with the Friedreich Ataxia Rating Scale score, an indicator of disease severity.
These novel findings provide compelling evidence for the link between the GAA expansion, the DNA methylation profile, FXN expression, and clinical outcome in FA. Epigenetic profiling of FXN could be used to gain greater insight into disease onset and progression, but also as a biomarker to learn more about specific treatment responses and pharmacological mechanism(s). This work also highlights the potential for developing therapies aimed at increasing frataxin levels to treat this debilitating disease.
Annals of Neurology 04/2012; 71(4):487-97. · 11.19 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The safety and effectiveness of tetrabenazine in different sub-populations of Huntington disease (HD) is not known. In this study, we evaluated the safety of tetrabenazine in individuals on an antidepressant and its effectiveness in advanced HD. Tetrabenazine was not associated with an increased incidence of depressed mood among those taking antidepressants and was effective at reducing chorea in those with advanced HD.
[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to examine the relationship between CAG repeat length (CAGn) and clinical progression in patients with Huntington's disease (HD). There are conflicting reports about the relationship between CAGn and clinical progression of HD. We conducted an analysis of data from the Coenzyme Q10 and Remacemide Evaluation in Huntington's Disease (CARE-HD) clinical trial. We modeled progression over 30 months on the Unified Huntington's Disease Rating Scale (UHDRS) and supplemental neuropsychological and behavioral tests using multiple linear regression. Mean subject age was 47.9 +/- 10.5 years and mean CAGn was 45.0 +/- 4.1. Multiple linear regression revealed statistically significant associations between CAGn and worsening on several motor, cognitive, and functional outcomes, but not behavioral outcomes. Many effects were clinically important; 10 additional CAG repeats were associated with an 81% increase in progression on the Independence Scale. These associations were not observed in the absence of age adjustment. Age at the time of assessment confounds the association between CAGn and progression. Adjusting for age shows that longer CAGn is associated with greater clinical progression of HD. This finding may account for the variable results from previous studies examining CAGn and progression. Adjusting for CAGn may be important for clinical trials.
Movement Disorders 06/2008; 23(9):1223-7. · 5.63 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To compare the Morisky medication adherence questionnaire to pill counts as measures of adherence in the NET-PD futility clinical trials. Background: Like in other chronic diseases, non-adherence with medications occurs in Parkinson's disease (PD), although nonadherence has not been of significant concern in most PD clinical trials. The most common approach to assessment is to do a pill count at each visit. The simple, 4-question Morisky medication adherence questionnaire may provide an alternative approach to monitoring treatment adherence in PD.
Adherence data from two NET-PD Phase II clinical trials enrolling a total of 413 participants were analyzed. The association between demographic and clinical characteristics and adherence was explored.
Ninety-percent of participants took 80% or more of the study drug. However, the Morisky medication adherence questionnaires showed 56% report high and 44% report medium adherence. Agreement between the two measures is fair (ICC = 0.40).
Overall adherence as assessed by pill count appears high. The Morisky medication adherence questionnaire may be useful in PD clinical trials, since it is moderately correlated to pill count and may be more sensitive to nonadherence.
Movement Disorders 05/2007; 22(6):822-7. · 4.56 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The best way to initiate dopaminergic therapy for early Parkinson disease remains unclear.
To compare initial treatment with pramipexole vs levodopa in early Parkinson disease, followed by levodopa supplementation, with respect to the development of dopaminergic motor complications, other adverse events, and functional and quality-of-life outcomes.
Multicenter, parallel-group, double-blind, randomized controlled trial.
Academic movement disorders clinics at 22 sites in the United States and Canada.
Patients with early Parkinson disease (N = 301) who required dopaminergic therapy to treat emerging disability, enrolled between October 1996 and August 1997 and observed until August 2001.
Subjects were randomly assigned to receive 0.5 mg of pramipexole 3 times per day with levodopa placebo (n = 151) or 25/100 mg of carbidopa/levodopa 3 times per day with pramipexole placebo (n = 150). Dosage was escalated during the first 10 weeks for patients with ongoing disability. Thereafter, investigators were permitted to add open-label levodopa or other antiparkinsonian medications to treat ongoing or emerging disability.
Time to the first occurrence of dopaminergic complications: wearing off, dyskinesias, on-off fluctuations, and freezing; changes in the Unified Parkinson's Disease Rating Scale and quality-of-life scales; and adverse events.
Initial pramipexole treatment resulted in a significant reduction in the risk of developing dyskinesias (24.5% vs 54%; hazard ratio, 0.37; 95% confidence interval [CI], 0.25-0.56; P<.001) and wearing off (47% vs 62.7%; hazard ratio, 0.68; 95% CI, 0.49-0.63; P =.02). Initial levodopa treatment resulted in a significant reduction in the risk of freezing (25.3% vs 37.1%; hazard ratio, 1.7; 95% CI, 1.11-2.59; P =.01). By 48 months, the occurrence of disabling dyskinesias was uncommon and did not significantly differ between the 2 groups. The mean improvement in the total Unified Parkinson's Disease Rating Scale score from baseline to 48 months was greater in the levodopa group than in the pramipexole group (2 +/- 15.4 points vs -3.2 +/- 17.3 points, P =.003). Somnolence (36% vs 21%, P =.005) and edema (42% vs 15%, P<.001) were more common in pramipexole-treated subjects than in levodopa-treated subjects. Mean changes in quality-of-life scores did not differ between the groups.
Initial treatment with pramipexole resulted in lower incidences of dyskinesias and wearing off compared with initial treatment with levodopa. Initial treatment with levodopa resulted in lower incidences of freezing, somnolence, and edema and provided for better symptomatic control, as measured by the Unified Parkinson's Disease Rating Scale, compared with initial treatment with pramipexole. Both options resulted in similar quality of life. Levodopa and pramipexole both appear to be reasonable options as initial dopaminergic therapy for Parkinson disease, but they are associated with different efficacy and adverse-effect profiles.