A proof-of-concept, randomized, placebo-controlled, multiple cross-overs (n-of-1) study of naftazone in Parkinson's disease
ABSTRACT To explore for the first time the tolerability and efficacy of naftazone in patients with Parkinson's disease (PD). Proof-of-concept, randomized, double-blind, placebo-controlled, multiple-cross-over n-of-1 study in patients with PD with wearing-off and dyskinesias. Naftazone was titrated up to 120 mg/day during an initial single-blind dose-finding phase. Seven patients entered the placebo-controlled phase (four consecutive 28-day cross-overs). Three outcome measures were used to collect preliminary indices of efficacy: (i) 48-h ON-OFF diaries; (ii) Unified PD Rating Scale (UPDRS) part III while ON; (iii) seven-point Likert scale to assess "patients' discomfort caused by dyskinesias" (Q1) and 'disability during OFF-periods' (Q2). A 'responder' analysis (proportion of patients with mean treatment effect [naftazone minus placebo] favoring naftazone over the 4 cross-over periods) was used. Treatment effects were derived from mixed-effects anova. On diaries, 5/7 patients responded to naftazone for 'ON-time with troublesome dyskinesia' (reduced time, treatment effect: -49 [95% CI: -93/-4] min, P = 0.03), 6/7 regarding 'ON-time without troublesome dyskinesia' (increased time, treatment effect: 35 [-19/88], P = 0.2). No trend was observed for 'OFF' time. There were 7/7 'responders' regarding UPDRSIII (reduced score, treatment effect: -2.1[-4.5/0.2], P = 0.08). The 7-point scales did not show clear trends in favor of naftazone (3/7 responders for Q1 and 4/7 for Q2). Four of the seven patients reported adverse events after randomization, mostly related to the CNS (mild: 2, severe: 2). These pilot findings are consistent with preclinical data in primates and support the hypothesis that naftazone may have antiparkinsonian and antidyskinetic effects in humans that deserve further clinical investigation.
SourceAvailable from: Erwan Bezard[Show abstract] [Hide abstract]
ABSTRACT: BACKGROUND: Simvastatin may improve levodopa-induced dyskinesia through striatal Ras-extracellular signal-regulated kinase pathway modulation. METHODS: (1) Six 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated macaques were assessed for parkinsonism and dyskinesia severity following acute co-administration of levodopa and simvastatin (0, 1.5, 3 and 6 mg/kg). (2) A "n-of-1" design randomized, placebo-controlled, 3 cross-over trial was then conducted in 10 Parkinson's disease patients with troublesome dyskinesia. The primary endpoint was a 7-point scale rating subjective discomfort caused by troublesome dyskinesia. Secondary endpoints related to dyskinesia severity and duration and functional impairment, severity and duration of OFF periods, motor scores and investigator- and patient-rated global impressions. (3) The pharmacodynamic variable for both studies consisted in a multiplex analysis of kinase-induced phosphorylation in T and B-lymphocytes by flow cytometry. RESULTS: (1) In the macaque, simvastatin reduced dyskinesia scores (45%), at the dose of 3 mg/kg (2) In the "n-of-1" trial no significant response was observed in the primary end point and all secondary endpoints. No serious adverse events were reported. (3) Simvastatin 3 mg/kg significantly reduce kinase-induced phosphorylation in monkeys but not simvastatin 40 mg in patients. CONCLUSIONS: Simvastatin reduced dyskinesia in primates using high doses over 3 mg/kg but the exploratory trial in patients revealed no effect at 40 mg/d suggesting that higher doses, not compatible with a safe prolonged administration, are necessary.Parkinsonism & Related Disorders 12/2012; 19(4). DOI:10.1016/j.parkreldis.2012.12.003 · 4.13 Impact Factor
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ABSTRACT: l-3,4-Dihydroxyphenylalanine (l-DOPA) remains the most effective symptomatic treatment of Parkinson's disease (PD). However, long-term administration of l-DOPA is marred by the emergence of abnormal involuntary movements, i.e., l-DOPA-induced dyskinesia (LID). Years of intensive research have yielded significant progress in the quest to elucidate the mechanisms leading to the development and expression of dyskinesia and maintenance of the dyskinetic state, but the search for a complete understanding is still ongoing. Herein, we summarize the current knowledge of the pharmacology of LID in PD. Specifically, we review evidence gathered from postmortem and pharmacological studies, both preclinical and clinical, and discuss the involvement of dopaminergic and nondopaminergic systems, including glutamatergic, opioid, serotonergic, γ-aminobutyric acid (GABA)-ergic, adenosine, cannabinoid, adrenergic, histaminergic, and cholinergic systems. Moreover, we discuss changes occurring in transcription factors, intracellular signaling, and gene expression in the dyskinetic phenotype. Inasmuch as a multitude of neurotransmitters and receptors play a role in the etiology of dyskinesia, we propose that to optimally alleviate this motor complication, it may be necessary to develop combined treatment approaches that will target simultaneously more than one neurotransmitter system. This could be achieved via three ways as follows: 1) by developing compounds that will interact simultaneously to a multitude of receptors with the required agonist/antagonist effect at each target, 2) by targeting intracellular signaling cascades where the signals mediated by multiple receptors converge, and/or 3) to regulate gene expression in a manner that has effects on signaling by multiple pathways.Pharmacological reviews 12/2013; 65(1):171-222. DOI:10.1124/pr.111.005678 · 18.55 Impact Factor