oxadiazoles and Parkinson-Disease

Topics: Antiparkinson Agents; Catechol O-Methyltransferase Inhibitors; Clinical Trials, Phase IV as Topic; Humans; Levodopa; Oxadiazoles; Parkinson Disease

Motor complications, characterized by "off" periods - when anti-parkinsonian medications are ineffective - and dyskinesia, are the hallmark of advanced Parkinson's disease (PD). While levodopa is the gold standard PD medication in terms of efficacy, its short duration of effect coupled with progressive loss of dopaminergic neurons leads to motor complications and fails to treat off periods.. This review focuses on novel dopaminergic therapies that were recently made clinically available or are currently in development for the treatment of motor complications. First, it will discuss rescue therapies for the treatment of off episodes, including novel apomorphine and levodopa formulations. Second, it will highlight adjunctive dopaminergic medications approved to reduce total daily off time. Third, it will discuss longer-acting levodopa formulations in development and introduce a novel selective dopamine agonist under study. Finally, it will cover novel dopaminergic delivery mechanisms, with specific focus on continuous subcutaneous infusions in development.. The breadth of dopaminergic therapies recently approved or in development for motor complications, and specifically off time reduction, evokes cautious optimism. Gains in reducing off time with rescue therapies, adjunctive medications or longer-acting levodopa formulations are modest, and underscore the need for more continuous dopaminergic delivery to address the underlying pathophysiology and translate to clinically meaningful improvement in motor complications.

Topics: Alanine; Antiparkinson Agents; Apomorphine; Benzylamines; Delayed-Action Preparations; Disease Progression; Dopamine Agents; Dopamine Agonists; Drug Compounding; Drug Delivery Systems; Dyskinesias; Humans; Levodopa; Oxadiazoles; Parkinson Disease

Parkinson's disease (PD) is a common neurodegenerative disorder. It is also the fastest-growing neurodegenerative disorder and has more than doubled between 1990 and 2016. Parkinson's disease causes significant morbidity and disability from motor dysfunction, sleep disturbances, and cognitive and psychiatric symptoms. This paper reviews recent evidence in the treatment of PD "off" episodes with the novel drug opicapone, including its efficacy, safety, and clinical indications. Opicapone is a novel, peripherally acting catechol-O-methyl transferase (COMT) inhibitor used as adjunctive therapy to carbidopa/levodopa for treatment and prevention of "off" episodes. It has been approved for use as an adjunct to levodopa since 2016 in Europe and has recently (April 2020) gained FDA approval for use in the USA. By inhibiting COMT, opicapone slows levodopa metabolism and increases its availability. Several clinical studies demonstrated significant improvement in treatment efficacy and reduction in the duration of "off" episodes The main side effect demonstrated was dyskinesia, mostly with the 100 mg dose, which is higher than the approved, effective dose of 50 mg.

Topics: Antiparkinson Agents; Catechol O-Methyltransferase; Catechol O-Methyltransferase Inhibitors; Humans; Oxadiazoles; Parkinson Disease

Long-term levodopa administration for treating Parkinson's disease (PD) may shorten the duration of effect and cause dyskinesias, inducing the need for catechol-O-methyltransferase (COMT) inhibitors as adjuvant therapy.. We provide pooled scientific evidence highlighting the efficacy and safety of opicapone, a newly approved COMT inhibitor, as an adjuvant to levodopa.. We searched Ovid Medline, Embase, and Cochrane databases for relevant reports. Efficacy and safety were evaluated as off-time reduction and risk ratio (RR) of dyskinesia, respectively. Data were independently extracted using predefined criteria. Selected placebo-controlled trials were divided into double-blind and open-label periods. Using a random-effects model, the mean difference (MD) of the off-time reduction (efficacy), RR for the occurrence of dyskinesia, and on-time without/with troublesome dyskinesia (TD; safety assessment) were compared between opicapone and placebo groups.. Five studies from three randomized controlled trials were included, and a meta-analysis was performed with 407 patients receiving opicapone 50 mg and 402 patients receiving placebo. Compared with the placebo, opicapone (50 mg) reduced off-time by 49.91 min during the double-blind period (95% confidence intervals [CIs] = -71.39, -28.43; I2 = 0%). The RR of dyskinesia was 3.43 times greater in the opicapone 50 mg group than in the placebo group (95% CI = 2.14, 5.51; I = 0%). Compared with the placebo, opicapone increased the on-time without TD by 44.62 min (95% CI = 22.60, 66.64; I2 = 0%); the on-time increase with TD did not differ between treatments.. Opicapone can play a positive role as an adjuvant to levodopa in patients with PD by reducing off-time and prolonging on-time without PD.

Topics: Antiparkinson Agents; Catechol O-Methyltransferase; Catechol O-Methyltransferase Inhibitors; Dyskinesias; Humans; Levodopa; Oxadiazoles; Parkinson Disease; Randomized Controlled Trials as Topic

Topics: Adult; Antiparkinson Agents; Catechol O-Methyltransferase Inhibitors; Double-Blind Method; Humans; Levodopa; Oxadiazoles; Parkinson Disease

Levodopa remains the gold-standard Parkinson's disease (PD) treatment, but the inevitable development of motor complications has led to intense activity in pursuit of its optimal delivery.. Peripheral inhibition of dopa-decarboxylase has long been considered an essential component of levodopa treatment at every stage of illness. In contrast, only relatively recently have catechol-O-methyltransferase (COMT) inhibitors been utilized to block the other major pathway of degradation and optimize levodopa delivery to the brain. First and second-generation COMT inhibitors were deficient because of toxicity, sub-optimal pharmacokinetics or a short duration of effect. As such, they have only been employed once 'wearing-off' has developed. However, the third-generation COMT inhibitor, opicapone has overcome these difficulties and exhibits long-lasting enzyme inhibition without the toxicity observed with previous generations of COMT inhibitors. In clinical trials and real-world PD studies opicapone improves the levodopa plasma profile and results in a significant improvement in ON time in 'fluctuating' disease, but it has not yet been included in the algorithm for early treatment.. This review argues for a shift in the positioning of COMT inhibition with opicapone in the PD algorithm and lays out a pathway for proving its effectiveness in early disease.

Topics: Antiparkinson Agents; Catechol O-Methyltransferase; Catechol O-Methyltransferase Inhibitors; Humans; Levodopa; Oxadiazoles; Parkinson Disease

Opicapone is a catechol-O-methyl-transferase (iCOMT) inhibitor authorized in Europe in 2016 and indicated as adjunctive therapy to preparations of levodopa/ DOPA decarboxylase inhibitors in adult patients with Parkinson's disease and end-of-dose motor fluctuations who cannot be stabilised on those combinations. The efficacy of opicapone in these patients has been demonstrated in two pivotal randomized clinical trials, BIPARK I and BIPARK II, in which it has demonstrated its superiority versus placebo and non-inferiority versus entacapone. Although they constitute the gold standard for the evaluation of interventions, randomized clinical trials present limitations of external validity due to the use of strict eligibility criteria. Therefore, it is considered necessary to have a more comprehensive evaluation of the efficacy of the drug, complementing the information obtained from randomized clinical trials with that of "real world or real clinical practice" studies. The objective of this review has been to collect and put into perspective the information available on opicapone coming from real clinical practice studies in Spain. The data from Spain with opicapone in 18 series with more than 1,000 patients in total, confirm the safety and efficacy previously reported with this iCOMT. Furthermore, they show that opicapone is especially useful in patients with a less advanced stage of the disease and mild motor fluctuations, which would suggest that the earlier its introduction in the therapeutic scheme for the management of motor fluctuations, the better is the benefit-risk ratio for the drug.. Opicapona para el tratamiento de la enfermedad de Parkinson: datos de vida real en España.. Resumen. La opicapona es un inhibidor de la catecol-O-metiltransferasa (iCOMT) autorizado en Europa en 2016 como terapia adyuvante a las preparaciones de levodopa/inhibidores de la dopa descarboxilasa en pacientes adultos con enfermedad de Parkinson y fluctuaciones motoras de final de dosis que no puedan ser estabilizados con esas combinaciones. La eficacia de la opicapona en estos pacientes ha sido demostrada en dos ensayos clínicos pivotales, BIPARK I y BIPARK II, en los que se ha demostrado la superioridad frente al placebo y la no inferioridad frente a la entacapona. A pesar de que constituyen el estándar para la evaluación de intervenciones, los ensayos clínicos aleatorizados presentan limitaciones de validez externa debidas a la utilización de criterios estrictos de elegibilidad. Por tanto, se considera necesario disponer de una evaluación más amplia de la eficacia general del fármaco, complementando la información de los ensayos clínicos aleatorizados con estudios de ‘vida real o práctica clínica real’. El objetivo de esta revisión ha sido recopilar y poner en perspectiva la información disponible sobre los resultados de la opicapona en estudios de práctica clínica real en España. Los datos acumulados en España con opicapona en 18 series con más de 1.000 pacientes confirman la seguridad y la eficacia de este iCOMT comunicadas previamente. Además, muestran que la opicapona es especialmente útil en pacientes en un estadio de la enfermedad menos avanzado y fluctuaciones motores leves, lo que sugeriría una mejor relación beneficio-riesgo cuanto más temprana sea su introducción en el esquema terapéutico para el tratamiento de las fluctuaciones motoras.

Topics: Antiparkinson Agents; Catechol O-Methyltransferase Inhibitors; Combined Modality Therapy; Deep Brain Stimulation; Drug Therapy, Combination; Humans; Levodopa; Oxadiazoles; Parkinson Disease; Quality of Life; Randomized Controlled Trials as Topic; Retrospective Studies; Risk Assessment; Spain; Treatment Outcome

Selective monoamine oxidase type B (MAO-B) inhibitors are currently used as coadjuvants for treating early motor symptoms of Parkinson's disease. Aiming at the elucidation of MAO-B inhibitors with 1,3,4-oxadiazole scaffolds, we make a comprehensive update on the new and old chemical methods employed for the synthesis of the unsymmetrical oxadiazole derivatives that lead to high yield compounds. We summarize a state of the selective MAO-B inhibitors with oxadiazole scaffold, describing the results, structures, structure-activity relationships (SARs) and medicinal chemistry strategies over the years. The analysis of the recent papers would facilitate tracking the increasing number of oxadiazole derivatives as new chemical spaces with MAO-B inhibitory potential designed to ensure the safe use of the compounds and elimination of the unwanted drug-drug interactions.

Topics: Cyclization; Dehydration; Drug Design; Humans; Isomerism; Monoamine Oxidase; Monoamine Oxidase Inhibitors; Neuroprotection; Oxadiazoles; Oxidation-Reduction; Parkinson Disease; Protective Agents; Small Molecule Libraries; Structure-Activity Relationship

Topics: Administration, Oral; Adult; Antiparkinson Agents; Catechol O-Methyltransferase Inhibitors; Catechols; Drug Therapy, Combination; Humans; Nitriles; Oxadiazoles; Parkinson Disease

Topics: Antiparkinson Agents; Catechol O-Methyltransferase; Catechol O-Methyltransferase Inhibitors; Clinical Trials as Topic; Humans; Oxadiazoles; Parkinson Disease

Opicapone (OPC) is a well-established catechol-O-methyltransferase (COMT) inhibitor that is approved for the treatment of Parkinson's disease (PD) associated with L-DOPA/L-amino acid decarboxylase inhibitor (DDI) therapy allowing for prolonged activity due to a more continuous supply of L-DOPA in the brain. Thus, OPC decreases fluctuation in L-DOPA plasma levels and favors more constant central dopaminergic receptor stimulation, thus improving PD symptomatology.. This review evaluates the preclinical development, pharmacology, pharmacokinetics and safety profile of OPC. Data was extracted from published preclinical and clinical studies published on PUBMED and SCOPUS (Search period: 2000-2019). Clinical and post-marketing data are also evaluated.. OPC is a third generation COMT inhibitor with a novel structure. It has an efficacy and tolerability superior to its predecessors, tolcapone (TOL) and entacapone (ENT). It also provides a safe and simplified drug regimen that allows neurologists to individually adjust the existing daily administration of L-DOPA. OPC is indicated as an adjunctive therapy to L-DOPA/DDI in patients with PD and end-of-dose motor fluctuations who cannot be stabilized on those combinations.

Topics: Animals; Antiparkinson Agents; Catechol O-Methyltransferase Inhibitors; Drug Development; Drug Evaluation, Preclinical; Humans; Levodopa; Oxadiazoles; Parkinson Disease

Motor fluctuations are frequently seen in Parkinson disease patients on chronic treatment with levodopa. Management of motor fluctuation includes the addition of catechol-O-methyl transferase (COMT) inhibitors. Opicapone is a recent and selective third-generation COMT inhibitor which achieves marked increase in the bioavailability of levodopa. We present a consensus of a group of Spanish neurologists with extensive experience in the clinical management of motor fluctuations. The clinical experience of this group of experts is in line with clinical trials and confirms that opicapone is an effective drug in the control of motor fluctuations, regardless of the daily levodopa dose, or the use of other antiparkinsonian drugs. However, in the opinion of these experts, the ideal patient with Parkinson's disease to initiate treatment with opicapone is the one with mild motor fluctuations, since the ratio between clinical efficacy and adverse effects is more favorable. In general, it is an easy-to-use drug both in those first treated with a COMT inhibitor or those already on entacapone. In any case, the secondary side effects are easily managed.. Optimización del manejo clínico de opicapona en la enfermedad de Parkinson. Recomendaciones de expertos españoles.. Las fluctuaciones motoras constituyen una importante complicación en los pacientes con enfermedad de Parkinson tratados con levodopa. Entre las opciones terapéuticas para el manejo de las fluctuaciones motoras se cuenta con los inhibidores de la catecol-O-metil-transferasa (COMT), incluyendo la opicapona. La opicapona muestra una elevada afinidad por la COMT y consigue un aumento marcado de la biodisponibilidad de la levodopa. Se presenta el consenso de un grupo de expertos españoles en la enfermedad de Parkinson con experiencia en el tratamiento clínico de fluctuaciones motoras y el empleo de opicapona. La experiencia de este grupo de expertos, en consonancia con los ensayos clínicos, confirma que la opicapona es un fármaco eficaz en el control de las fluctuaciones motoras de la enfermedad de Parkinson, con independencia de la dosis de levodopa recibida o de la utilización de otros fármacos antiparkinsonianos. No obstante, a juicio de estos expertos, el paciente ideal para iniciar el tratamiento con opicapona es el que presenta fluctuaciones motoras leves, ya que muestra una mejor relación entre eficacia clínica y efectos adversos. En general, la opicapona es un fármaco de fácil manejo, tanto en pacientes que requieren opicapona como primer inhibidor de la COMT como en los previamente tratados con entacapona, o en los que están en tratamiento concomitante con otros fármacos antiparkinsonianos. En cualquier caso, los efectos secundarios son fácilmente corregibles.

Topics: Antiparkinson Agents; Catechol O-Methyltransferase Inhibitors; Catechols; Clinical Trials as Topic; Dopamine Agonists; Drug Administration Schedule; Drug Substitution; Drug Therapy, Combination; Humans; Levodopa; Nitriles; Oxadiazoles; Parkinson Disease; Patient Selection; Treatment Outcome

The deficiency pattern of neurotransmitters is heterogeneous in patients with Parkinson's disease. Consequence is an individual variable expression of motor and nonmotor features. They respond to agents with a broader spectrum of mode of actions, whereas dopamine substitution only targets impaired motor behavior. The pharmacological profile of safinamide includes reversible monoamine oxidase B inhibition and modulation of voltage-dependent sodium- and calcium channels with consecutive decline of glutamate release. Safinamide improves motor and nonmotor symptoms. Combination of safinamide with the catechol-O-methyltransferase inhibitor opicapone in one capsule is a promising future treatment alternative, which simplifies drug therapy in Parkinson's disease. Both agents complement each other in terms of application mode and efficacy on motor complications as adjuncts to levodopa therapy.

Topics: Adolescent; Adult; Alanine; Antiparkinson Agents; Benzylamines; Catechol O-Methyltransferase Inhibitors; Female; Humans; Levodopa; Male; Middle Aged; Oxadiazoles; Parkinson Disease; Young Adult

Topics: Administration, Oral; Antiparkinson Agents; Catechol O-Methyltransferase Inhibitors; Catechols; Dyskinesia, Drug-Induced; Humans; Levodopa; Nitriles; Oxadiazoles; Parkinson Disease

Opicapone (OPC) is a novel, potent, reversible, and purely peripheral third-generation COMT inhibitor, which provides an enhancement in levodopa (L-Dopa) availability. It represents adjunctive therapy for L-Dopa treated patients with PD and motor fluctuations. Areas covered: The purpose of this study was to evaluate pharmacokinetic of OPC for the treatment of PD. Expert commentary: Oral OPC exhibits linear, dose-dependent absorption. However, following concomitant ingestion of a high-fat, high-calorie meal, the maximum plasma concentration will be decreased. A once-daily bedtime administration of OPC 1 h after the last daily L-Dopa/AADCi, are considered to avoid any interaction during the L-Dopa absorption phase. There are no clinically relevant effects of age (in adults), renal impairment or race on the pharmacokinetics of OPC. OPC dose adjustment is not needed in patients with mild to moderate chronic hepatic impairment. Opicapone exhibits the lowest potential for cytotoxicity in comparison with other COMT inhibitors. It significantly decreases COMT activity, with half-life of COMT inhibition in human erythrocytes of 61.6 h and increases systemic exposure to L-Dopa. This provides an enhancement in L-Dopa availability that translates into clinical benefit for PD patients in terms of significant decrease of OFF periods and increase in ON-time without troublesome dyskinesia.

Topics: Adult; Animals; Antiparkinson Agents; Catechol O-Methyltransferase Inhibitors; Dose-Response Relationship, Drug; Drug Therapy, Combination; Food-Drug Interactions; Half-Life; Humans; Levodopa; Oxadiazoles; Parkinson Disease

Opicapone is a novel, third generation COMT inhibitor approved for the treatment of Parkinson's disease. Safety and tolerability data is critical to determine the benefit-harm balance and anticipate therapeutic adherence. Areas covered: This review evaluates the tolerability and safety profile of opicapone. These data were extracted from all published clinical trials, including preclinical, phase I, phase II and phase III studies as well as postmarketing data. Opicapone was safe and well tolerated, with frequencies of treatment-emergent adverse events similar to placebo. Expert opinion: Opicapone have shown a good safety and tolerability profile. This adds to its proven efficacy and convenient once-daily administration, supporting a role of opicapone as a first-line therapy for motor complications in Parkinson's disease patients.

Topics: Animals; Antiparkinson Agents; Catechol O-Methyltransferase Inhibitors; Drug Administration Schedule; Humans; Oxadiazoles; Parkinson Disease

Topics: Animals; Antiparkinson Agents; Deep Brain Stimulation; Humans; Levodopa; Oxadiazoles; Parkinson Disease

Catechol-O-methyl transferase inhibitors are currently used as first-line add-on therapy to levodopa for the treatment of end-of-dose motor fluctuations in Parkinson's disease patients, as they increase levodopa bioavailability. Several factors hamper the use of current available catechol-O-methyl transferase inhibitors, that is, the moderate efficacy and multiple dosing for entacapone and the risk of liver toxicity with tolcapone. Opicapone, a new long-acting, peripherally selective, once-daily catechol-O-methyl transferase inhibitor, was recently licensed in Europe. Two phase 3 double-blind clinical trials demonstrated opicapone efficacy in reducing OFF time by an average of about 60 minutes daily compared with placebo, without increasing ON time with troublesome dyskinesias. These effects were also maintained during a subsequent open-label extension consisting of 1-year follow-up. Opicapone showed a good safety profile. From June 2016, Opicapone received the approval for marketing authorization from the European Commission as adjunctive therapy to levodopa/DOPA decarboxylase inhibitors in patients with PD and end-of-dose motor fluctuations. We aimed to review the clinical pharmacological data of opicapone, summarize its clinical efficacy and safety issues, and discuss its potential role in the management of Parkinson's disease. © 2018 International Parkinson and Movement Disorder Society.

Topics: Antiparkinson Agents; Catechol O-Methyltransferase Inhibitors; Humans; Levodopa; Oxadiazoles; Parkinson Disease

Opicapone is a third generation, highly potent and effective catechol O‑methyltransferase (COMT) inhibitor that optimizes the pharmacokinetics and bioavailability of L-DOPA therapy. Areas covered: In this review, the authors describe the preclinical and clinical development of opicapone. In PD patients with motor fluctuations, once daily opicapone administration was well-tolerated and consistently reduced OFF-time and increased ON-time without increasing the frequency of troublesome dyskinesia, and these benefits were maintained over at least a year of continued open-label therapy. Expert commentary: With its convenient once-daily regimen, adjunct opicapone should be considered as an effective option for use in L-DOPA treated PD patients experiencing motor fluctuations.

Topics: Antiparkinson Agents; Catechol O-Methyltransferase Inhibitors; Dopamine Agents; Drug Therapy, Combination; Humans; Levodopa; Oxadiazoles; Parkinson Disease

Parkinson's disease (PD) is a progressive, chronic, neurodegenerative disease characterized by rigidity, tremor, bradykinesia and postural instability secondary to dopaminergic deficit in the nigrostriatal system. Currently, disease-modifying therapies are not available, and levodopa (LD) treatment remains the gold standard for controlling motor and nonmotor symptoms of the disease. LD is extensively and rapidly metabolized by peripheral enzymes, namely, aromatic amino acid decarboxylase and catechol-

Topics: Antiparkinson Agents; Drug Design; Drug Therapy, Combination; Humans; Levodopa; Oxadiazoles; Parkinson Disease

Parkinson's disease (PD) is a progressive neurodegenerative disease. The currently available treatment options only have a symptomatic effect. With disease progression almost all antiparkinsonian pharmacological classes are tried, but the gold standard of pharmacological management is still L-dopa. Various strategies can be used to raise the dopaminergic tone. Catechol-O-methyltransferase (COMT) inhibitors attain this goal by decreasing L-dopa peripheral metabolism. Areas covered: Opicapone (Ongentys®) is a new COMT inhibitor developed to fulfill the need for more potent, safer and longer acting COMT inhibitors. This review puts into context opicapone's indications, its chemical and preclinical data, the pharmacodynamics and pharmacokinetic characteristics, and the efficacy and safety results delivered by clinical trials. Expert opinion: Opicapone is an efficacious COMT inhibitor. Its proprieties make it adequate for a once-a-day oral dose regimen. It has proved to reduce the off-time and to increase the on-time without troublesome dyskinesias in PD patients with motor fluctuations. The reported adverse events suggest an overall safe and well-tolerated profile. The most common adverse events were dyskinesia, and there were no issues of concern for hepatotoxicity, severe diarrhoea or chromaturia. Further evidence is still needed to conclude how it compares with other drugs for the treatment of motor fluctuations.

Topics: Antiparkinson Agents; Catechol O-Methyltransferase; Catechol O-Methyltransferase Inhibitors; Disease Progression; Dopamine; Humans; Oxadiazoles; Parkinson Disease

Oral opicapone (Ongentys(®)), a potent, third-generation, long-acting, peripheral catechol-O-methyltransferase (COMT) inhibitor, is approved as adjunctive treatment to levodopa (L-Dopa)/dopa-decarboxylase inhibitor (DDCI) therapy in adults with Parkinson's disease (PD) and end-of-dose motor fluctuations who cannot be stabilized on those combinations. In 14- to 15-week, double-blind, multinational trials and in 1-year, open-label extension studies in this patient population, opicapone was an effective and generally well tolerated adjunctive therapy to L-Dopa plus a DDCI and other PD therapy. During the double-blind phase, adjunctive opicapone 50 mg once daily provided significantly greater improvements in motor fluctuations than placebo, with these improvements noninferior to those with entacapone. These beneficial improvements in motor fluctuations with opicapone were maintained in patients who continued adjunctive opicapone during the extension studies, with patients who switched from placebo or entacapone to opicapone experiencing significant improvements in motor fluctuations during this year. No new unexpected safety concerns were identified after ≈1.4 years' treatment with opicapone, with no serious cases of hepatotoxicity reported in clinical trials. With its convenient once-daily regimen, oral opicapone is an emerging COMT inhibitor option for use as adjunctive therapy to L-Dopa/DDCI therapy in adults with PD and end-of dose motor fluctuations who cannot be stabilized on those combinations.

Topics: Adult; Aged; Aged, 80 and over; Antiparkinson Agents; Aromatic Amino Acid Decarboxylase Inhibitors; Catechol O-Methyltransferase Inhibitors; Double-Blind Method; Drug Interactions; Drug Therapy, Combination; Humans; Levodopa; Middle Aged; Oxadiazoles; Parkinson Disease

Two catechol-O-methyl transferase inhibitors are currently used as add-on therapy to levodopa for the amelioration of end-of-dose motor fluctuations in Parkinson's disease patients: entacapone, which has moderate efficacy and requires multiple dosing, and tolcapone, which has a poor safety profile. Opicapone (OPC) is a novel, long-acting, peripherally selective, once daily, third-generation catechol-O-methyl transferase inhibitor. Two Phase III clinical trials demonstrated OPC efficacy in reducing OFF-time by an average of about 60 min daily compared with placebo, without increasing ON-time with troublesome dyskinesias, with a good drug safety profile. In June 2016, the European Commission granted a marketing authorization valid throughout the European Union for OPC, indicated as adjunctive of levodopa decarboxylase inhibitors in adult patients with Parkinson's disease and end-of-dose motor fluctuations.

Topics: Antiparkinson Agents; Catechol O-Methyltransferase Inhibitors; Drug Therapy, Combination; Humans; Levodopa; Oxadiazoles; Parkinson Disease; Pharmacology, Clinical

Topics: Acridines; Animals; Brain; Cytoplasm; Hydrazines; Iproniazid; Isoquinolines; Liver; Membranes; Mitochondria; Monoamine Oxidase Inhibitors; Oxadiazoles; Pargyline; Parkinson Disease; Pyridines; Pyrroles; Radiation Injuries; Rats; Tranylcypromine; Vitamin D

Optimisation of dopaminergic therapy may alleviate fluctuation-related pain in Parkinson's disease (PD). Opicapone (OPC) is a third-generation, once-daily catechol-O-methyltransferase inhibitor shown to be generally well tolerated and efficacious in reducing OFF-time in two pivotal trials in patients with PD and end-of-dose motor fluctuations. The OpiCapone Effect on motor fluctuations and pAiN (OCEAN) trial aims to investigate the efficacy of OPC 50 mg in PD patients with end-of-dose motor fluctuations and associated pain, when administered as adjunctive therapy to existing treatment with levodopa/dopa decarboxylase inhibitor (DDCi).. OCEAN is a Phase IV, international, multicentre, randomised, double-blind, placebo-controlled, parallel-group, interventional trial in PD patients with end-of-dose motor fluctuations and associated pain. It consists of a 1-week screening period, 24-week double-blind treatment period and 2-week follow-up period. Eligible patients will be randomised 1:1 to OPC 50 mg or placebo once daily while continuing current treatment with levodopa/DDCi and other chronic, stable anti-PD and/or analgesic treatments. The primary efficacy endpoint is change from baseline in Domain 3 (fluctuation-related pain) of the King's Parkinson's disease Pain Scale (KPPS). The key secondary efficacy endpoint is change from baseline in Domain B (anxiety) of the Movement Disorder Society-sponsored Non-Motor rating Scale (MDS-NMS). Additional secondary efficacy assessments include other domains and total scores of the KPPS and MDS-NMS, the Parkinson's Disease Questionnaire (PDQ-8), the MDS-sponsored Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Parts III and IV, Clinical and Patient's Global Impressions of Change, and change in functional status via Hauser's diary. Safety assessments include the incidence of treatment-emergent adverse events. The study will be conducted in approximately 140 patients from 50 clinical sites in Germany, Italy, Portugal, Spain and the United Kingdom. Recruitment started in February 2021 and the last patient is expected to complete the study by late 2022.. The OCEAN trial will help determine whether the use of adjunctive OPC 50 mg treatment can improve fluctuation-associated pain in PD patients with end-of-dose motor fluctuations. The robust design of OCEAN will address the current lack of reliable evidence for dopaminergic-based therapy in the treatment of PD-associated pain.. EudraCT number 2020-001175-32 ; registered on 2020-08-07.

Topics: Antiparkinson Agents; Catechol O-Methyltransferase; Humans; Oxadiazoles; Pain; Parkinson Disease

This placebo-controlled, randomized study evaluated the efficacy and safety of opicapone 25-mg and 50-mg tablets in Japanese levodopa-treated patients with Parkinson's disease and motor fluctuations.. Japanese adults (n = 437, age 39-83 years) with Parkinson's disease (United Kingdom Parkinson's Disease Society criteria) received opicapone 25-mg (n = 145), opicapone 50-mg (n = 145), or placebo (n = 147) tablets over the double-blind treatment period (14-15 weeks). The primary efficacy assessment was change in OFF-time; secondary efficacy assessments included OFF/ON-time responders (≥1 hour change from baseline), total ON-time, ON-time with and without troublesome dyskinesia, and Unified Parkinson's Disease Rating Scale.. The least squares mean (standard error) change in OFF-time from baseline to the last visit was -0.42 (0.21) hour for the placebo group, -1.16 (0.22) hour for the opicapone 25 mg group, and -1.04 (0.21) hour for the opicapone 50 mg group. The percentage of ON-time responders, changes in total ON-time/ON-time without troublesome dyskinesia, and Unified Parkinson's Disease Rating Scale II (at OFF) all showed statistically significant improvements versus placebo for both opicapone tablet doses (P < 0.05). Unified Parkinson's Disease Rating Scale III (at ON) was improved versus placebo in patients who received opicapone 50 mg (P < 0.05). Adverse events were more common in patients treated with opicapone 25 mg (60.0%) or opicapone 50 mg (54.5%) versus placebo (48.3%). The most commonly reported adverse event was dyskinesia (placebo, 2.7%; opicapone 25 mg, 9.0%; opicapone 50 mg, 12.4%).. In Japanese patients, both opicapone 25 and 50 mg were significantly more effective than placebo with no dose-dependent difference in efficacy, and both doses were well tolerated. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Topics: Adult; Aged; Aged, 80 and over; Antiparkinson Agents; Double-Blind Method; Humans; Japan; Levodopa; Middle Aged; Oxadiazoles; Parkinson Disease; Treatment Outcome; United Kingdom

The double-blind part of the COMFORT-PD (COMt-inhibitor Findings from Opicapone Repeated Treatment for Parkinson's Disease) study in Japanese levodopa-treated patients with Parkinson's disease and motor fluctuations found that both opicapone 25 and 50 mg were significantly more effective than placebo. This 52-week open-label extension study evaluated the long-term safety and efficacy of opicapone 50 mg tablets in patients who completed the double-blind part of the COMFORT-PD study. Safety was monitored via adverse events, laboratory testing, and physical, cardiovascular and neurological examinations. Efficacy was primarily assessed by change in OFF-time. Secondary efficacy measures included: ON-time, percentage of OFF/ON-time responders, other outcomes from the double-blind part. 391/437 patients were transferred to the open-label extension period and included in the safety analysis set (full analysis set, n = 387; open-label completers, n = 316). Adverse events were frequently reported (n = 338, 86.4%), but < 50% were considered drug-related (39.9%) and few were considered serious (2.6%) or led to discontinuation (2.8%). Decreased OFF-time was consistently observed over the open-label period regardless of initial randomization. Change [LSM (SE)] in OFF-time from the open-label baseline to the last visit showed a persistent effect in patients initially randomized to opicapone 25 mg [- 0.37 (0.20) h, P = 0.0689] and opicapone 50 mg [- 0.07 (0.21) h, P = 0.6913] whereas opicapone 50 mg led to a statistically significant reduction in the previous placebo group [- 1.26 (0.19) h, P < 0.05]. Once-daily opicapone 50 mg was generally well tolerated and consistently reduced OFF-time over 52 weeks in Japanese levodopa-treated patients with motor fluctuations.Trial registration JapicCTI-153112; date of registration: December 25, 2015.

Topics: Antiparkinson Agents; Double-Blind Method; Humans; Japan; Levodopa; Oxadiazoles; Parkinson Disease

The efficacy and safety of opicapone, a once-daily catechol-O-methyltransferase inhibitor, have been established in two large randomized, placebo-controlled, multinational pivotal trials. Still, clinical evidence from routine practice is needed to complement the data from the pivotal trials.. OPTIPARK (NCT02847442) was a prospective, open-label, single-arm trial conducted in Germany and the UK under clinical practice conditions. Patients with Parkinson's disease and motor fluctuations were treated with opicapone 50 mg for 3 (Germany) or 6 (UK) months in addition to their current levodopa and other antiparkinsonian treatments. The primary endpoint was the Clinician's Global Impression of Change (CGI-C) after 3 months. Secondary assessments included Patient Global Impressions of Change (PGI-C), the Unified Parkinson's Disease Rating Scale (UPDRS), Parkinson's Disease Questionnaire (PDQ-8), and the Non-Motor Symptoms Scale (NMSS). Safety assessments included evaluation of treatment-emergent adverse events (TEAEs) and serious adverse events (SAEs).. Of the 506 patients enrolled, 495 (97.8%) took at least one dose of opicapone. Of these, 393 (79.4%) patients completed 3 months of treatment. Overall, 71.3 and 76.9% of patients experienced any improvement on CGI-C and PGI-C after 3 months, respectively (full analysis set). At 6 months, for UK subgroup only (n = 95), 85.3% of patients were judged by investigators as improved since commencing treatment. UPDRS scores at 3 months showed statistically significant improvements in activities of daily living during OFF (mean ± SD change from baseline: - 3.0 ± 4.6, p < 0.0001) and motor scores during ON (- 4.6 ± 8.1, p < 0.0001). The mean ± SD improvements of - 3.4 ± 12.8 points for PDQ-8 and -6.8 ± 19.7 points for NMSS were statistically significant versus baseline (both p < 0.0001). Most of TEAEs (94.8% of events) were of mild or moderate intensity. TEAEs considered to be at least possibly related to opicapone were reported for 45.1% of patients, with dyskinesia (11.5%) and dry mouth (6.5%) being the most frequently reported. Serious TEAEs considered at least possibly related to opicapone were reported for 1.4% of patients.. Opicapone 50 mg was effective and generally well-tolerated in PD patients with motor fluctuations treated in clinical practice.. Registered in July 2016 at clinicaltrials.gov (NCT02847442).

Topics: Adult; Aged; Aged, 80 and over; Antiparkinson Agents; Catechol O-Methyltransferase Inhibitors; Double-Blind Method; Female; Germany; Humans; Male; Middle Aged; Oxadiazoles; Parkinson Disease; Prospective Studies; Treatment Outcome; United Kingdom

Opicapone is a catechol O-methyltransferase (COMT) inhibitor indicated for use as adjunct to levodopa therapy in patients with Parkinson's disease (PD) and motor fluctuations.. To characterize the safety and tolerability of adjunct opicapone (25 and 50 mg) in a pooled population of levodopa-treated PD patients who participated in the opicapone Phase-3 clinical program.. Patient-level data (placebo, opicapone 25 mg and 50 mg) from the BIPARK-1 and BIPARK-2 double-blind and open-label studies were combined.. Pooled analyses included 766 patients from the double-blind studies and 848 patients from the open-label studies. In the double-blind studies, 63.3% of opicapone-treated patients reported treatment-emergent adverse events (TEAEs) versus 57.2% in the placebo group. The most common TEAEs reported in the opicapone group compared to placebo were dyskinesia, constipation and insomnia. The incidence of serious TEAEs was similar across opicapone and placebo groups (3.5% versus 4.3%, respectively). Overall, 71.3% patients treated with open-label opicapone reported at least one TEAE; most occurred within the first 2 months of the open-label studies, and then decreased thereafter. Throughout the Phase-3 clinical program, there were no serious AEs suggestive of hepatic toxicity, and the incidence of gastrointestinal disorders such as nausea and diarrhea remained low (<2%). There were no relevant changes in laboratory parameters including liver enzymes, vital signs, physical or neurological examinations, or ECG readings.. Long-term use of opicapone once-daily over 1-year at doses of 25 mg or 50 mg was generally safe and well tolerated, supporting its clinical usefulness in the management of PD motor fluctuations.

Topics: Aged; Antiparkinson Agents; Catechol O-Methyltransferase Inhibitors; Double-Blind Method; Drug Therapy, Combination; Female; Humans; Levodopa; Male; Middle Aged; Oxadiazoles; Parkinson Disease; Treatment Outcome

The aim was to evaluate the efficacy of the catechol-O-methyltransferase inhibitor opicapone (25 and 50 mg) as adjunct therapy to levodopa in a pooled population of Parkinson's disease patients who participated in the pivotal double-blind trials of opicapone and their 1-year open-label extensions.. Data (placebo, opicapone 25 mg and opicapone 50 mg) from the BIPARK-1 and BIPARK-2 double-blind and open-label studies were combined. The studies had similar designs, eligibility criteria and assessment methods. The primary efficacy variable in both double-blind studies was the change from baseline in absolute OFF time based on patient diaries.. Double-blind treatment with opicapone (25 and 50 mg) significantly reduced absolute daily OFF time from a baseline of 6.1-6.6 h. The mean (and 95% confidence interval) treatment effect versus placebo was -35.1 (-62.1, -8.2) min (P = 0.0106) for the 25 mg dose and -58.1 (-84.5, -31.7) min (P < 0.0001) for the 50 mg dose. Reductions in OFF time were mirrored by significant increases in ON time without troublesome dyskinesia (P < 0.05 and P < 0.0001 for the 25 and 50 mg doses, respectively). No significant differences were observed for ON time with troublesome dyskinesia. Patient diary results from the open-label phase indicated a maintenance of effect for patients previously treated with opicapone 50 mg. The group previously treated with the 25 mg dose benefitted with further optimization of therapy during the open-label phase, whilst switching from placebo to opicapone led to significant reductions in OFF time and increased ON time.. Over at least 1 year of open-label therapy, opicapone consistently reduced OFF time and increased ON time without increasing the frequency of troublesome dyskinesia.

Topics: Aged; Antiparkinson Agents; Double-Blind Method; Drug Therapy, Combination; Female; Humans; Levodopa; Male; Middle Aged; Oxadiazoles; Parkinson Disease; Treatment Outcome

Catechol O-methyltransferase (COMT) inhibitors are an established treatment for end-of-dose motor fluctuations associated with levodopa therapy in patients with Parkinson disease (PD). Current COMT inhibitors carry a high risk for toxic effects to hepatic cells or show moderate improvement. Opicapone was designed to be effective without the adverse effects.. To evaluate the efficacy and safety of 25- and 50-mg/d dosages of opicapone compared with placebo as adjunct to levodopa therapy in patients with PD experiencing end-of-dose motor fluctuations.. This phase 3 international, multicenter outpatient study evaluated a 25- and a 50-mg/d dosage of opicapone in a randomized, double-blind, 14- to 15-week, placebo-controlled clinical trial, followed by a 1-year open-label phase during which all patients received active treatment with opicapone. Patients with PD who experienced signs of end-of-dose deterioration and had a mean total awake off-time (state of akinesia or decreased mobility) of at least 1.5 hours, not including morning akinesia, were enrolled. Data were collected from March 18, 2011, through June 25, 2013. Data from the evaluable population were analyzed from July 31, 2013, to July 31, 2014.. The primary efficacy outcome of the double-blind phase was the change from baseline in absolute off-time vs placebo based on patient diaries. The open-label phase focused on maintenance of treatment effect in off-time.. A total of 427 patients (258 men [60.4%] and 169 women [39.6%]; mean [SD] age, 63.1 [8.8] years) were randomized to a 25-mg/d (n = 129) or a 50-mg/d (n = 154) dosage of opicapone or to placebo (n = 144). Of these, 376 patients completed the double-blind phase and entered the open-label phase, of whom 286 completed 1 year of open-label treatment. At the end of the double-blind phase, the least squares mean change (SE) in off-time was -64.5 (14.4) minutes for the placebo group, -101.7 (14.9) minutes for the 25-mg/d opicapone group, and -118.8 (13.8) minutes for the 50-mg/d opicapone group. The adjusted treatment difference vs placebo was significant for the 50-mg/d opicapone group (treatment effect, -54.3 [95% CI, -96.2 to -12.4] minutes; P = .008), but not for the 25-mg/d opicapone group (treatment effect, -37.2 [95% CI, -80.8 to 6.4] minutes; P = .11). The off-time reduction was sustained throughout the open-label phase (-126.3 minutes at 1-year open-label end point). The most common adverse events in the opicapone vs placebo groups were dyskinesia, constipation, and dry mouth. Fifty-one patients (11.9%) discontinued from the study during the double-blind phase.. Treatment with a 50-mg once-daily dose of opicapone was associated with a significant reduction in mean daily off-time in levodopa-treated patients with PD and motor fluctuations, and this effect is maintained for at least 1 year. Opicapone was safe and well tolerated.. clinicaltrials.gov Identifier: NCT01227655.

Topics: Adult; Aged; Aged, 80 and over; Antiparkinson Agents; Dose-Response Relationship, Drug; Double-Blind Method; Female; Follow-Up Studies; Humans; International Cooperation; Levodopa; Male; Middle Aged; Motor Activity; Oxadiazoles; Parkinson Disease; Severity of Illness Index

Opicapone is a novel, once-daily, potent third-generation catechol-O-methyltransferase inhibitor. We aimed to assess the safety and efficacy of opicapone as an adjunct to levodopa compared with placebo or entacapone in patients with Parkinson's disease and motor fluctuations.. We did a randomised, double-blind, placebo-controlled and active-controlled trial of opicapone as an adjunct to levodopa in patients with Parkinson's disease with end-of-dose motor fluctuations. Patients aged 30-83 years were enrolled at 106 specialist centres across 19 European countries and Russia and were randomly assigned (1:1:1:1:1) by a proprietary computer-generated sequence to oral treatment with opicapone (5 mg, 25 mg, or 50 mg once daily), placebo, or entacapone (200 mg with every levodopa intake) for 14-15 weeks. Patients and investigators (ie, outcome assessors) were masked to treatment allocation. The primary endpoint was the change from baseline to end of study treatment in absolute time in the off state, as assessed by daily paper patient diaries; the primary analysis followed a hierarchical procedure for each opicapone dose in which superiority compared with placebo in the full analysis set was first tested and then, if positive, non-inferiority to entacapone was tested in the per-protocol set with a margin of 30 min. This trial is registered with EudraCT, 2010-021860-13, and ClinicalTrials.gov, NCT01568073.. Between March 31, 2011, and Nov 30, 2013, of 679 patients screened, 600 were randomly assigned. 590 patients were included in the full analysis set (120 in the placebo group, 120 in the entacapone group, 119 in the opicapone 5 mg group, 116 in the opicapone 25 mg group, and 115 in the opicapone 50 mg group) and 537 in the per-protocol set (112 in the placebo group, 104 in the entacapone group, 110 in the opicapone 5 mg group, 105 in the opicapone 25 mg group, and 106 in the opicapone 50 mg group). The mean change in time in the off state was -56·0 min (SE 13·4; 95% CI -82·3 to -29·7) for placebo, -96·3 min (13·4; -122·6 to -70·0) for entacapone, -91·3 min (13·5; -117·7 to -64·8) for opicapone 5 mg, -85·9 min (13·7; -112·8 to -59·1) for opicapone 25 mg, and -116·8 min (14·0; -144·2 to -89·4) for opicapone 50 mg. Treatment with opicapone 50 mg was superior to placebo (mean difference in change from baseline -60·8 min, 95% CI -97·2 to -24·4; p=0·0015) and non-inferior to entacapone (-26·2 min, -63·8 to 11·4; p=0·0051). Treatment with opicapone 5 mg (p=0·056) or 25 mg (p=0·080) was not significantly different from treatment with placebo. Treatment-emergent adverse events were reported in 60 (50%) of 121 patients in the placebo group, 69 (57%) of 122 in the entacapone group, 63 (52%) of 122 in the opicapone 5 mg group, 65 (55%) of 119 in the opicapone 25 mg group, and 62 (54%) of 115 in the opicapone 50 mg group. The most common adverse events were dyskinesia (in five patients in the placebo group, ten in the entacapone group, 17 in the opicapone 5 mg group, nine in the opicapone 25 mg group, and 18 in the opicapone 50 mg group), insomnia (in one, seven, two, seven, and seven patients, respectively), and constipation (in three, five, four, none, and seven patients, respectively). Serious adverse events were reported in six patients in the placebo group, eight in the entacapone group, four each in the opicapone 5 mg and opicapone 50 mg groups, and one in the opicapone 25 mg group.. The addition of opicapone 50 mg to levodopa treatment in patients with Parkinson's disease and end-of-dose motor fluctuations could enable a simplified drug regimen that allows physicians to individually tailor the existing levodopa daily regimen, by potentially reducing the total daily levodopa dose, increasing the dosing interval, and ultimately reducing the number of intakes, thereby maximising its benefit.. BIAL.

Topics: Adult; Aged; Aged, 80 and over; Antiparkinson Agents; Catechol O-Methyltransferase Inhibitors; Catechols; Double-Blind Method; Drug Therapy, Combination; Dyskinesia, Drug-Induced; Europe; Female; Humans; Levodopa; Male; Middle Aged; Nitriles; Outcome Assessment, Health Care; Oxadiazoles; Parkinson Disease

This study determined the effects of single doses of opicapone (OPC), a novel third-generation catechol-O-methyltransferase (COMT) inhibitor, on levodopa and 3-O-methyl-levodopa (3-OMD) pharmacokinetics (PK), COMT activity and motor fluctuations in patients with Parkinson disease (PD). Subjects received, in a double-blind manner, 25, 50, and 100 mg OPC or placebo (PLC) in 4 separate treatment periods. The washout period between doses was at least 10 days. During each period, the OPC/PLC capsules were to be coadministered with the morning dose of 100/25 mg levodopa/carbidopa (LC) or levodopa/benserazide (LB) on day 3. In relation to PLC, levodopa exposure increased 3.7%, 16.4%, and 34.8% following 25, 50, or 100 mg OPC, respectively. Maximum S-COMT inhibition (Emax ) ranged from 67.8% (25 mg OPC) to 100% (100 mg OPC). Peak and extent of S-COMT inhibition were dose-dependent. Maximum decrease in the plasma 3-OMD was observed following administration of 100 mg OPC. Opicapone administered concomitantly with standard-release 100/25 mg LC or LB improved motor performance. Treatments were generally well tolerated and safe. It was concluded that OPC is a new COMT inhibitor that significantly decreased COMT activity and increased systemic exposure to levodopa in PD patients with motor fluctuations.

Topics: Adult; Aged; Antiparkinson Agents; Benserazide; Carbidopa; Catechol O-Methyltransferase; Catechol O-Methyltransferase Inhibitors; Cross-Over Studies; Dose-Response Relationship, Drug; Double-Blind Method; Drug Combinations; Drug Interactions; Female; Humans; Levodopa; Male; Middle Aged; Oxadiazoles; Parkinson Disease

Opicapone (OPC) is a novel third generation catechol-O-methyltransferase (COMT) inhibitor that enhances levodopa availability. This study investigated the effects of OPC in comparison with placebo on levodopa pharmacokinetics, tolerability and safety, COMT activity and motor response to levodopa in Parkinson's disease (PD) patients with motor fluctuations.. This was a randomized, multicentre, double-blind and placebo-controlled study in four parallel groups of PD patients treated with standard-release 100/25 mg levodopa/carbidopa or levodopa/benserazide and with motor fluctuations (wearing-OFF phenomenon). Subjects were sequentially assigned to be administered, once-daily, up to 28 days (maintenance phase), placebo (n = 10) or 5 (n = 10), 15 (n = 10) and 30 mg (n = 10) OPC. Two levodopa tests were performed, one at baseline and another following the maintenance phase. Subjects kept a diary to record motor fluctuations (ON/OFF periods) throughout the study.. In relation to placebo, levodopa exposure (AUC0-6) increased 24.7%, 53.9% and 65.6% following 5, 15 and 30 mg OPC, respectively. Maximum COMT inhibition (Emax) ranged from 52% (5 mg OPC) to 80% (30 mg OPC). The study was not designed to detect any significant differences in motor performance, but the exploratory analysis performed shows improvement in various motor outcomes, including a dose-dependent change in absolute OFF time corresponding to a percentage decrease of 4.16% (P > 0.05), 29.55% (P > 0.05) and 32.71% (P < 0.05) with 5, 15 and 30 mg OPC, respectively. Treatments were generally well tolerated and safe.. OPC is a promising new COMT inhibitor that significantly decreased COMT activity, increased systemic exposure to levodopa and improved motor response.

Topics: Aged; Aged, 80 and over; Antiparkinson Agents; Benserazide; Carbidopa; Catechol O-Methyltransferase; Catechol O-Methyltransferase Inhibitors; Double-Blind Method; Drug Combinations; Female; Humans; Levodopa; Male; Middle Aged; Oxadiazoles; Parkinson Disease; Treatment Outcome

Inflammation is one of a major feature of Parkinson's disease (PD) which poses a threat to people's health in the world. It has been reported that antioxidation and anti-inflammation have significant effects on the treatment of PD. 1,2,4-oxadiazole and flavone derivatives have remarkable antioxidant and anti-inflammatory activities. In order to find highly effective drugs for PD treatment, based on the remarkable anti-inflammatory and antioxidant activities of the 1,2,4-oxadiazole pharmacophore and the flavonoid pharmacophore, we designed and synthesized a novel series of 3-methyl-8-(3-methyl-1,2,4-oxadiazol-5-yl)-2-phenyl-4H-chromen-4-one derivatives by pharmacophore combination, and evaluated their anti-inflammatory and antioxidation activities for PD treatment. Preliminary structure-activity relationship (SAR) analysis was conducted by their inhibitory activities against reactive oxygen species (ROS) and NO release in LPS-induced BV2 Microglia cells, and the optimal compound Flo8 exhibited the most potent anti-inflammatory and antioxidant activities. Both in vivo and in vitro results showed that Flo8 inhibited neuronal apoptosis by inhibiting inflammatory and apoptotic signaling pathways. In vivo studies also showed that the compound Flo8 ameliorated motor and behavioral deficits and increased serum dopamine levels in MPTP-induced PD model mice. Taken together, this study demonstrated the compound Flo8 could be a promising agent for the treatment of PD.

Topics: Animals; Anti-Inflammatory Agents; Antioxidants; Disease Models, Animal; Flavones; Mice; Mice, Inbred C57BL; Microglia; Neuroprotective Agents; Oxadiazoles; Parkinson Disease; Structure-Activity Relationship

Motor fluctuations are a significant driver of healthcare resource utilization (HCRU) in people with Parkinson's disease (pwPD). A common management strategy is to include catechol-O-methyltransferase (COMT) inhibition with either opicapone or entacapone in the levodopa regimen. However, to date, there has been a lack of head-to-head data comparing the two COMT inhibitors in real-world settings. The aim of this study was to evaluate changes in HCRU and effect on sleep medications when opicapone was initiated as first COMT inhibitor versus entacapone.. In this retrospective cohort study, we assessed HCRU outcomes in pwPD naïve to COMT inhibition via UK electronic healthcare records (Clinical Practice Research Datalink and Hospital Episodes Statistics databases, June 2016 to December 2019). HCRU outcomes were assessed before (baseline) and after COMT inhibitor prescription at 0-6 months, 7-12 months and 13-18 months. Opicapone-treated pwPD were algorithm-matched (1:4) to entacapone-treated pwPD.. By 6 months, treatment with opicapone resulted in 18.5% fewer neurology outpatient visits compared to entacapone treatment; this effect was maintained until the last follow-up (18 months). In the opicapone group, the mean levodopa equivalent daily dose decreased over the first year and then stabilized, whereas the entacapone-treated group showed an initial decrease in the first 6 months followed by a dose increase between 7 and 18 months. Neither COMT inhibitor had a significant impact on sleep medication use.. This head-to-head study is the first to demonstrate, using 'real-world' data, that initiating COMT inhibition with opicapone is likely to decrease the need for post-treatment HCRU versus initiation of COMT inhibition with entacapone.

Topics: Antiparkinson Agents; Catechol O-Methyltransferase; Catechol O-Methyltransferase Inhibitors; Humans; Levodopa; Oxadiazoles; Parkinson Disease; Patient Acceptance of Health Care; Retrospective Studies

Patients with Parkinson's disease (PD) often experience motor fluctuations (reduced and variable response to medication) following prolonged treatment with levodopa, which is currently the most effective treatment for the symptoms of PD. Opicapone has been developed for use in combination with levodopa to reduce the occurrence of motor fluctuations and was shown to be effective in two large clinical trials. This study describes the effectiveness, safety and cost-saving impact of opicapone when used to treat patients with PD and motor fluctuations across everyday clinical practice in the UK. Six months' treatment with opicapone was generally well tolerated, resulted in an improvement of the patients' overall PD condition and reduced treatment costs.

Topics: Antiparkinson Agents; Catechol O-Methyltransferase Inhibitors; Costs and Cost Analysis; Double-Blind Method; Humans; Levodopa; Oxadiazoles; Parkinson Disease; United Kingdom

The OPTIPARK study confirmed the effectiveness and safety of opicapone as adjunct therapy to levodopa in patients with Parkinson's disease (PD) and motor fluctuations under real-world conditions. The aim of this sub-analysis was to evaluate opicapone in the German patient cohort of OPTIPARK in order to provide country-specific data.. OPTIPARK was an open-label, single-arm study conducted in routine clinical practice across Germany and the UK. Patients with PD and motor fluctuations received once-daily opicapone 50 mg for 3 months in addition to levodopa. The primary endpoint was Clinicians' Global Impression of Change (CGI-C). Secondary assessments included Patients' Global Impressions of Change (PGI-C), Unified Parkinson's Disease Rating Scale (UPDRS) I-IV, Parkinson's Disease Questionnaire (PDQ-8), and Non-Motor Symptoms Scale (NMSS). This sub-analysis reports outcomes from the German patients only.. Overall, 363 (97.6%) of the 372 patients included in the German cohort received ≥1 dose of opicapone and 291 (80.2%) completed the study. Improvements on CGI-C and PGI-C were reported by 70.8% and 76.3% of patients, respectively. UPDRS scores improved for activities of daily living during OFF time by -3.3 ± 4.5 points and motor scores during ON time by -5.3 ± 7.9 points. PDQ-8 and NMSS scores also demonstrated improvements. Treatment emergent adverse events considered at least possibly related to opicapone occurred in 37.7% of patients, with most being of mild or moderate intensity.. Opicapone added to levodopa in patients with PD and motor fluctuations was effective and generally well tolerated in routine clinical practice across Germany.

Topics: Activities of Daily Living; Antiparkinson Agents; Double-Blind Method; Drug Therapy, Combination; Germany; Humans; Levodopa; Oxadiazoles; Parkinson Disease

The catechol-O-methyltransferase inhibitors entacapone and opicapone prolong the efficacy of conventional oral levodopa/dopa decarboxylase inhibitor formulations through an increase in levodopa plasma bioavailability. Catechol-O-methyltransferase inhibitors influence the homocysteine metabolism associated with levodopa/dopa decarboxylase application. The objectives of this study were to compare the impact of additional single-day entacapone or opicapone intake on the pharmacokinetic plasma behaviour of levodopa, 3-O-methyldopa and total homocysteine in 15 Parkinson's disease patients, with concomitant scoring of motor symptoms, under standardized conditions. The patients received opicapone plus two doses of 100 mg levodopa/carbidopa and, one week later, two doses of levodopa/carbidopa/entacapone or vice versa. Levodopa, 3-O-methyldopa and total homocysteine were determined with reversed-phase high-performance liquid chromatography. Levodopa bioavailability and its maximum concentration were higher with opicapone. The computed peak-to-trough difference was lower after the second levodopa administration with entacapone. The fluctuation index of levodopa did not differ between both conditions. 3-O-methyldopa decreased on both days. Homocysteine levels did not significantly vary between both conditions. A significant homocysteine decrease occurred with entacapone, but not with opicapone. Motor behaviour improved with entacapone, but not with opicapone. Opicapone baseline scores were significantly better, and thus the potential for the improvement in motor symptoms was lower compared with the entacapone condition. The higher levodopa bioavailability with opicapone suggests that it is more efficacious than entacapone for the amelioration of "off" phenomena in fluctuating patients when co-administered with a levodopa/dopa decarboxylase inhibitor regimen. Both compounds prevented an increase in homocysteine, which is a metabolic marker for an impaired capacity in the performance of methylation processes.

Topics: Antiparkinson Agents; Aromatic Amino Acid Decarboxylase Inhibitors; Carbidopa; Catechol O-Methyltransferase; Catechol O-Methyltransferase Inhibitors; Catechols; Homocysteine; Humans; Levodopa; Nitriles; Oxadiazoles; Parkinson Disease

Topics: Aged; Antiparkinson Agents; Female; Humans; Levodopa; Male; Oxadiazoles; Parkinson Disease; Treatment Outcome

Topics: Antiparkinson Agents; Humans; Muscular Diseases; Oxadiazoles; Parkinson Disease

Since 2016, opicapone (OPC), a potent third-generation, long-acting, once-daily, peripheral catechol-O-methyltransferase inhibitor, is approved as an add-on to levodopa in Parkinson's disease patients with motor fluctuations. OPC 50 mg has showed to be able in reducing OFF time by an average of about 60 min daily compared with placebo, to further reduce OFF-time of about 39 min, when switched from ENT to OPC and to be safe. These beneficial effects of OPC were maintained for 1 year. Recently, several. Lay abstract Opicapone (OPC) is a recently marketed drug for treatment of Parkinson’s disease. It has been approved in Europe in 2016 and it is currently available in several countries, including Italy, Germany, Portugal, Spain, UK, Japan and US. The clinical indication of OPC is the presence of ‘OFF-period’, that means moments during which anti-parkinsonian medications are not doing effect and tremor or slowness are coming out. OPC is used in co-administration with levodopa, at night, once a daily. OPC does not slow the progression of the disease but can reduce of 1 h/day the ‘OFF periods’. It is well tolerated. It can be taken in concomitant with other anti-parkinsonian medications, but it can be required to readapt the dose of levodopa.

Topics: Antiparkinson Agents; Catechol O-Methyltransferase; Catechol O-Methyltransferase Inhibitors; Drug Therapy, Combination; Humans; Levodopa; Oxadiazoles; Parkinson Disease

Topics: Antiparkinson Agents; Humans; Levodopa; Oxadiazoles; Parkinson Disease; Portugal

Topics: Antiparkinson Agents; Catechol O-Methyltransferase; Catechol O-Methyltransferase Inhibitors; Catechols; Enzyme Inhibitors; Humans; Levodopa; Nitriles; Oxadiazoles; Parkinson Disease

Combined catechol-O-methyl-transferase-inhibition and Levodopa-Carbidopa intestinal gel (LCIG) infusion has the potential to reduce LCIG daily dose and the costs of this therapy. In this retrospective analysis, we report on Parkinson's disease (PD) patients on LCIG with concomitant Opicapone. In 11 patients, the introduction of Opicapone led to LCIG daily dose being reduced by 24.8% (p = 0.05) without any significant worsening of dyskinesia. Three patients withdrew from Opicapone due to side effects or inefficacy. LCIG daily dose reduction could lead to cost savings of £142,820.63/year in the United Kingdom while maintaining clinical care.

Topics: Aged; Carbidopa; Catechol O-Methyltransferase Inhibitors; Cost Savings; Delivery of Health Care; Dopamine Agonists; Drug Combinations; Female; Gels; Humans; Infusion Pumps, Implantable; Infusions, Parenteral; Levodopa; Male; Middle Aged; Oxadiazoles; Parkinson Disease; Retrospective Studies

Parkinson's disease (PD) is the second most common aging-related neurodegenerative disease worldwide. Oxidative stress and neuroinflammation are critical events in the degeneration of dopaminergic neurons in PD. In this study, we found that DDO-7263, a novel Nrf2-ARE activator reported by us, has ideal therapeutic effects on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinson's disease in mice. DDO-7263 improved the behavioral abnormalities induced by MPTP in mice, significantly attenuated chemically induced dopaminergic neuron loss of tyrosine hydroxylase (TH) in the substantia nigra (SN) and striatum of the mouse brain and inhibited the secretion of inflammatory factors. In addition, DDO-7263 protected PC12 neurons from H

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; Animals; Brain; Disease Models, Animal; Humans; Inflammasomes; Male; Mice; Mice, Inbred C57BL; MPTP Poisoning; Neuroprotective Agents; Neurotoxins; NF-E2-Related Factor 2; NLR Family, Pyrin Domain-Containing 3 Protein; Oxadiazoles; Oxidative Stress; Parkinson Disease; PC12 Cells; Rats

Freezing of gait (FOG) and postural instability are challenging motor symptoms that present a serious therapeutic dilemma in Parkinson's disease. Appropriate distinction between FOG subtypes may be difficult during routine clinical visits, as shown in the case we present. The patient was examined in three different states in relation to levodopa (L-DOPA) and apomorphine subcutaneous (sc) tests with video documentation: (1) 'overnight-off', after 12 hours without medication; (2)'on', 60 min after intake of regular levodopa dose (200 mg) and 20 min after 2 mg of apomorphine sc; and (3) 'supra-on', after 350 mg of L-DOPA and 3 mg of apomorphine sc. The patient clearly showed a dose-dependent paradoxical response to L-DOPA treatment with the emergence of severe FOG and postural instability. The tendency to develop these axial symptoms was less pronounced with apomorphine at doses that achieved similar improvements of other Parkinsonian features.

Topics: Aged; Antiparkinson Agents; Catechol O-Methyltransferase Inhibitors; Dose-Response Relationship, Drug; Gait Disorders, Neurologic; Humans; Levodopa; Male; Oxadiazoles; Parkinson Disease; Postural Balance; Sensation Disorders

To evaluate the effectiveness of opicapone as add-on to levodopa and the effects of switching from entacapone over 1 year of treatment in patients with fluctuating Parkinson disease.. After completion of a placebo- and entacapone-controlled double-blind study of opicapone (5, 25, or 50 mg), 495 patients continued to a 1-year extension phase in which patients were treated with opicapone. Patients began with once-daily opicapone 25 mg for 1 week, followed by individually tailored levodopa and/or opicapone dose adjustments. The primary efficacy variable was the change from baseline in absolute "off" time based on patient diaries. Other outcomes included proportion of responders, scale-based assessments, and standard safety assessments.. One year of treatment with opicapone reduced "off" time by a half-hour (33.8 minutes) vs the open-label baseline and >2 hours (126.9 minutes) vs the double-blind baseline. Whereas patients who were originally treated with opicapone 50 mg in the double-blind phase maintained their efficacy, switching treatments led to further decreases in "off" time (-64.9, -39.3, -27.5, and -23.0 minutes for switching from placebo, entacapone, and opicapone 5 and 25 mg, respectively). Dyskinesia was the most frequently reported adverse event (14.5%) and was managed by adjustment of dopaminergic therapy. No new safety concerns were observed with long-term opicapone administration.. Long-term use of opicapone provided sustained efficacy over 1 year. Switching from entacapone to opicapone led to enhanced efficacy under the conditions of the study.. This study provides Class III evidence that for patients with Parkinson disease and end-of-dose motor fluctuations, long-term use (52 weeks) of opicapone is well tolerated and reduces "off" time.

Topics: Aged; Antiparkinson Agents; Catechols; Double-Blind Method; Drug Therapy, Combination; Female; Humans; Levodopa; Male; Middle Aged; Nitriles; Oxadiazoles; Parkinson Disease; Treatment Outcome

Loss of dopaminergic neurons within the substantia nigra (SN) is a pathological hallmark of Parkinson's disease (PD), which leads to the onset of motor symptoms. Previously, our in vitro studies revealed that Angiotensin II (Ang II) induced apoptosis of dopaminergic neurons through its type 1 receptor (AT1R), but these findings needed to be confirmed via animal experiments. Here, using a rotenone-induced rat model of PD, we observed an overactivation of Ang II/AT1R axis in the SN, since Ang II level and AT1R expression were markedly increased. Furthermore, we provided in vivo evidence that Ang II directly elicited apoptosis of dopaminergic neurons via activation of AT1R in the SN of rats. More importantly, we showed for the first time that oral administration of azilsartan, a newly developed AT1R blocker approved by the U.S. Food and Drug Administration for hypertension treatment, rescued the apoptosis of dopaminergic neurons and relieved the characteristic parkinsonian symptoms in PD rats. These results support the application of AT1R blockers in PD therapy, and strengthen the notion that many therapeutic agents may possess pleiotropic action in addition to their main applications.

Topics: Angiotensin II; Angiotensin II Type 1 Receptor Blockers; Animals; Apoptosis; Behavior, Animal; Benzimidazoles; Disease Models, Animal; Dopaminergic Neurons; Humans; Male; Oxadiazoles; Parkinson Disease; Rats; Receptor, Angiotensin, Type 1; Substantia Nigra

Topics: Antiparkinson Agents; Humans; Levodopa; Oxadiazoles; Parkinson Disease

Topics: Antiparkinson Agents; Humans; Levodopa; Oxadiazoles; Parkinson Disease

Parkinson's disease is a neurodegenerative disorder characterized by a loss of nigrostriata dopaminergic neurons, which has been thought, at least in part, to result from oxidative stress. The present study aims to investigate the neuroprotective effects of stemazole (ST) on the dopamine (DA) system and its possible mechanisms of action in a mouse model of PD. Mice were injected intraperitoneally with MPTP (20mg/kg) four times at 2-h intervals for one day to induce Parkinsonism, and then treated with ST (10, 30 and 50mg/kg) or Madopar (120mg/kg) for 7days. Behavioral analyses were performed with locomotor activity measures and rotarod test. Tyrosine hydroxylase (TH) and dopamine transporter (DAT) levels were detected by immunohistochemistry method. DA and its metabolites were determined by high-performance liquid chromatography with an electrochemical detector. Oxidative stress levels were assessed by measuring the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX). Our results demonstrated that ST treatment improved locomotor activity and motor coordination in MPTP mice. There was also a significant increase in TH-positive cells (∼24%, P<0.01) and DAT levels (∼26%, P<0.01) in MPTP mice treated with ST (50mg/kg) compared with the vehicle group. Madopar treatment showed weaker effects on TH-positive cells (∼21%, P<0.05) and DAT levels (∼21%, P<0.05). DA and its metabolite levels were significantly increased with ST (50mg/kg) treatment (P<0.01, compared with the vehicle group). In addition, SOD and GSH-PX activities were elevated notably in ST treatment groups compared with the vehicle group. In conclusion, these results suggest that ST has neuroprotective effect on the impaired DA system, potentially through enhancement of the cell's anti-oxidative capacity. Hence it may be used as a potential therapeutic agent for Parkinson's disease.

Topics: 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; Animals; Benserazide; Corpus Striatum; Dopamine; Dopamine Plasma Membrane Transport Proteins; Drug Combinations; Hydrazines; Levodopa; Male; Mice, Inbred C57BL; Motor Activity; Neuroprotective Agents; Oxadiazoles; Oxidative Stress; Parkinson Disease; Substantia Nigra; Tyrosine 3-Monooxygenase

The present study aimed at evaluating the effect of opicapone, a third generation nitrocatechol catechol-O-methyltransferase (COMT) inhibitor, on the systemic and central bioavailability of 3,4-dihydroxy-l-phenylalanine (levodopa) and related metabolites in the cynomolgus monkey.. Four monkeys, implanted with guiding cannulas for microdialysis probes, in the substantia nigra, dorsal striatum and prefrontal cortex, were randomized in two groups that received, in a crossover design, vehicle or 100 mg/kg opicapone for 14 days. Twenty-three hours after last administration of vehicle or opicapone, animals were challenged with levodopa/benserazide (12/3 mg/kg). Extracellular dialysate and blood samples were collected over 360 min (at 30 min intervals) for the assays of catecholamine and COMT activity.. Opicapone increased levodopa systemic exposure by 2-fold not changing Cmax values and reduced both 3-O-methyldopa (3-OMD) exposure and Cmax values by 5-fold. These changes were accompanied by ∼76-84% reduction in erythrocyte COMT activity. In dorsal striatum and substantia nigra, opicapone increased levodopa exposure by 1.7- and 1.4-fold, respectively, reducing 3-OMD exposure by 5- and 7-fold respectively. DOPAC exposure was increased by 4-fold in the substantia nigra. In the prefrontal cortex, opicapone increased levodopa exposure and reduced 3-OMD levels by 2.3- and 2.4-fold, respectively.. Opicapone behaved as long-acting COMT inhibitor that markedly increased systemic and central levodopa bioavailability. Opicapone is a strong candidate to fill the unmet need for COMT inhibitors that lead to more sustained levodopa levels in Parkinson's disease patients.

Topics: Animals; Antiparkinson Agents; Brain; Catechol O-Methyltransferase Inhibitors; Cross-Over Studies; Dopamine Agents; Drug Interactions; Female; Levodopa; Macaca fascicularis; Male; Oxadiazoles; Parkinson Disease

Catechol O-methyltransferase (COMT) is the enzyme responsible for the O-methylation of endogenous neurotransmitters and of xenobiotic substances and hormones incorporating catecholic structures. COMT is a druggable biological target for the treatment of various central and peripheral nervous system disorders, including Parkinson's disease, depression, schizophrenia, and other dopamine deficiency-related diseases. The purpose of this perspective is fourfold: (i) to summarize the physiological role of COMT inhibitors in central and peripheral nervous system disorders; (ii) to provide the history and perspective of the medicinal chemistry behind the discovery and development of COMT inhibitors; (iii) to discuss how the physicochemical properties of recognized COMT inhibitors are understood to exert influence over their pharmacological properties; and (iv) to evaluate the clinical benefits of the most relevant COMT inhibitors.

Topics: Acetophenones; Animals; Catalysis; Catechol O-Methyltransferase; Catechol O-Methyltransferase Inhibitors; Catechols; Clinical Trials as Topic; Crystallography, X-Ray; Humans; Inhibitory Concentration 50; Levodopa; Male; Models, Molecular; Nitriles; Oxadiazoles; Parkinson Disease; Prodrugs; Rats

Alchemical free energy simulations are amongst the most accurate techniques for the computation of the free energy changes associated with noncovalent protein-ligand interactions. A procedure is presented to estimate the relative binding free energies of several ligands to the same protein target where multiple, low-energy configurational substates might coexist, as opposed to one unique structure. The contributions of all individual substates were estimated, explicitly, with the free energy perturbation method, and combined in a rigorous fashion to compute the overall relative binding free energies and dissociation constants. It is shown that, unless the most stable bound forms are known a priori, inaccurate results may be obtained if the contributions of multiple substates are ignored. The method was applied to study the complex formed between human catechol-O-methyltransferase and BIA 9-1067, a newly developed tight-binding inhibitor that is currently under clinical evaluation for the therapy of Parkinson's disease. Our results reveal an exceptionally high-binding affinity (K(d) in subpicomolar range) and provide insightful clues on the interactions and mechanism of inhibition. The inhibitor is, itself, a slowly reacting substrate of the target enzyme and is released from the complex in the form of O-methylated product. By comparing the experimental catalytic rate (k(cat)) and the estimated dissociation rate (k(off)) constants of the enzyme-inhibitor complex, one can conclude that the observed inhibition potency (K(i)) is primarily dependent on the catalytic rate constant of the inhibitor's O-methylation, rather than the rate constant of dissociation of the complex.

Topics: Catechol O-Methyltransferase; Catechol O-Methyltransferase Inhibitors; Computer Simulation; Enzyme Inhibitors; Humans; Models, Molecular; Molecular Conformation; Oxadiazoles; Parkinson Disease; Protein Binding; Thermodynamics

A series of 3-substituted aminocyclopentanes has been identified as highly potent and selective NR2B receptor antagonists. Incorporation of a 1,2,4-oxadiazole linker and substitution of the pendant phenyl ring led to the discovery of orally bioavailable analogues that showed efficient NR2B receptor occupancy in rats. Unlike nonselective NMDA antagonists, the NR2B-selective antagonist 22 showed no adverse affects on motor coordination in the rotarod assay at high dose. Compound 22 was efficacious following oral administration in a spinal nerve ligation model of neuropathic pain and in an acute model of Parkinson's disease in a dose dependent manner.

Topics: Administration, Oral; Animals; Benzopyrans; Biological Availability; Catalepsy; Cyclopentanes; Dogs; Drug Discovery; ERG1 Potassium Channel; Ether-A-Go-Go Potassium Channels; Excitatory Amino Acid Antagonists; Female; Half-Life; Indicators and Reagents; Isomerism; Ligation; Macaca mulatta; Male; Neuralgia; Oxadiazoles; Parkinson Disease; Piperidines; Pyrimidines; Rats; Rats, Sprague-Dawley; Receptors, N-Methyl-D-Aspartate; Spinal Nerves

[3H]Vesamicol binding was characterized in human brain post mortem. The number of binding sites was then determined in parallel with choline acetyltransferase activity in the temporal cortex of patients with Alzheimer's disease, demented and non-demented patients with Parkinson's disease, and in the cerebral cortex of rats with quisqualic acid lesions of the nucleus basalis magnocellularis. Whereas choline acetyltransferase activity decreased in patients with Alzheimer's or Parkinson's disease indicating loss of cholinergic innervation, the number of binding sites for [3H]vesamicol was the same as or higher than in controls. Similar results were obtained with the lesioned rats. It is suggested that the increase in binding sites may reflect compensatory regulation of the spared neurons at the level of the synaptic vesicle.

Topics: Aged; Aged, 80 and over; Alzheimer Disease; Animals; Brain Injuries; Choline O-Acetyltransferase; Female; Humans; Hydroxydopamines; Kinetics; Male; Neuromuscular Depolarizing Agents; Oxadiazoles; Oxidopamine; Parkinson Disease; Phencyclidine; Piperidines; Quisqualic Acid; Rats; Rats, Inbred Strains; Receptors, Neurotransmitter; Receptors, Phencyclidine; Reference Values; Substantia Nigra; Temporal Lobe

The density of calcium channel antagonist receptors labeled by (+)-[3H]PN 200-110 was reduced by 75% in striata from patients with Huntington's disease, but unchanged in patients with Parkinson's disease, compared with control subjects. These receptors are therefore likely to be localized to neurons with cell bodies in striatum, rather than nigrostriatal nerve terminals or glia, and their loss may contribute to the pathophysiology of basal ganglia disorders.

Topics: Aged; Calcium Channel Blockers; Corpus Striatum; Humans; Huntington Disease; Isradipine; Middle Aged; Nerve Degeneration; Neural Pathways; Neurons; Oxadiazoles; Parkinson Disease; Substantia Nigra