Update on the treatment of Parkinson's disease psychosis: role of pimavanserin

Metabolism, Disposition, Excretion, and Potential Transporter Inhibition of 7-16, an Improving 5-HT2A Receptor Antagonist and Inverse Agonist for Parkinson's Disease

Compound 7-16 was designed and synthesized in our previous study and was identified as a more potential selective 5-HT2A receptor antagonist and inverse agonist for treating Parkinson's disease psychosis (PDP). Then, the metabolism, disposition, and excretion properties of 7-16 and its potential inhibition on transporters were investigated in this study to highlight advancements in the understanding of its therapeutic mechanisms. The results indicate that a total of 10 metabolites of 7-16/[14C]7-16 were identified and determined in five species of liver microsomes and in rats using UPLC-Q Exactive high-resolution mass spectrometry combined with radioanalysis. Metabolites formed in human liver microsomes could be covered by animal species. 7-16 is mainly metabolized through mono-oxidation (M470-2) and N-demethylation (M440), and the CYP3A4 isozyme was responsible for both metabolic reactions. Based on the excretion data in bile and urine, the absorption rate of 7-16 was at least 74.7%. 7-16 had weak inhibition on P-glycoprotein and no effect on the transport activity of OATP1B1, OATP1B3, OAT1, OAT3, and OCT2 transporters. The comprehensive pharmacokinetic properties indicate that 7-16 deserves further development as a new treatment drug for PDP.

Ulotaront, a Trace Amine-Associated Receptor 1/Serotonin 5-HT1A Agonist, in Patients With Parkinson Disease Psychosis: A Pilot Study

Background and Objectives

Ulotaront (SEP-363856) is a trace amine-associated receptor 1 agonist with 5-HT_1A receptor agonist activity currently in phase 3 clinical development for the treatment of schizophrenia. In this exploratory, flexibly dosed study, ulotaront was evaluated for the treatment of Parkinson disease psychosis (PDP).

Methods

Patients with PDP requiring antipsychotic therapy were randomized, double-blind to ulotaront (25, 50, or 75 mg/d) or placebo. Mixed Model for Repeated Measures was used to assess change from baseline in the Scale for the Assessment of Positive Symptoms for Parkinson Disease (SAPS-PD) at 6 weeks (primary end point).

Results

The efficacy analysis sample comprised 38 patients (ulotaront, n = 24; placebo, n = 14). SAPS-PD total scores were numerically reduced in ulotaront-treated vs placebo-treated patients from week 1 to week 6: Least squares mean (95% confidence interval) difference in change from baseline at week 6 was -1.1 (-6.5, 4.3, p = 0.681). PDP symptom complete remission (≥100% improvement [reduction] from baseline in SAPS-PD total score) was observed in 25% of ulotaront-treated vs 0% of placebo-treated patients. SAPS-PD and Neuropsychiatric Inventory hallucinations subscales were numerically reduced vs placebo, and SAPS-PD total scores were reduced in patients with greater cognitive impairment (baseline Mini-Mental State Examination [MMSE] scores ≤24). Ulotaront improved Scales for Outcomes in Parkinson Disease Sleep Scale - Daytime Sleepiness scores (p = 0.022). There was no worsening of Unified Parkinson Disease Rating Scale Part III motor score, MMSE, or vital signs. Adverse events (≥10%) with ulotaront vs placebo included hallucinations (24% vs 14%), confusional state (20% vs 14%), dizziness (16% vs 7%), nausea (12% vs 7%), and falls (12% vs 21%).

Discussion

In this exploratory pilot study, ulotaront may decrease PDP symptoms without worsening motor function, particularly in patients with cognitive impairment.

Trial Registration Information

ClinicalTrials.gov identifier: NCT02969369; submitted: November 17, 2016; study start date: December 31, 2016.

Classification of Evidence

This Class II study was an exploratory pilot study that was underpowered to detect a statistically significant difference between ulotaront and placebo in the treatment of patients with Parkinson disease psychosis without worsening motor function.

Schizophrenia: Antipsychotics and drug development

The introduction of chlorpromazine and the work that ensued provided the foundation to reposition schizophrenia as a biological illness. The present paper follows the evolution of antipsychotics and their shift from 'typical' to 'atypical'. Atypicality is reviewed in reference to its original definition, clozapine's role, and developments that now leave the concept's utility in question. In a similar fashion, drug development is reviewed in the context of the illness' multiple symptom domains, as well as differences captured by clinical staging and phenotyping. Collectively, the evidence argues for a more nuanced approach to drug development that aligns with the illness' heterogeneity and complexity. Just as 'atypical' as a descriptor for antipsychotics may be outdated, it may be time to set aside the notion of developing drugs that treat 'schizophrenia'.

Clozapine: Why Is It So Uniquely Effective in the Treatment of a Range of Neuropsychiatric Disorders?

Clozapine is superior to other antipsychotics as a therapy for treatment-resistant schizophrenia and schizoaffective disorder with increased risk of suicidal behavior. This drug has also been used in the off-label treatment of bipolar disorder, major depressive disorder (MDD), and Parkinson's disease (PD). Although usually reserved for severe and treatment-refractory cases, it is interesting that electroconvulsive therapy (ECT) has also been used in the treatment of these psychiatric disorders, suggesting some common or related mechanisms. A literature review on the applications of clozapine and electroconvulsive therapy (ECT) to the disorders mentioned above was undertaken, and this narrative review was prepared. Although both treatments have multiple actions, evidence to date suggests that the ability to elicit epileptiform activity and alter EEG activity, to increase neuroplasticity and elevate brain levels of neurotrophic factors, to affect imbalances in the relationship between glutamate and γ-aminobutyric acid (GABA), and to reduce inflammation through effects on neuron-glia interactions are common underlying mechanisms of these two treatments. This evidence may explain why clozapine is effective in a range of neuropsychiatric disorders. Future increased investigations into epigenetic and connectomic changes produced by clozapine and ECT should provide valuable information about these two treatments and the disorders they are used to treat.

Treatment Patterns With Antipsychotics in Long-Term Care Patients With Parkinson's Disease Psychosis

This study assessed treatment change patterns in Parkinson's disease psychosis (PDP) residents receiving antipsychotic (AP) therapies in U.S. long-term care (LTC) facilities. Residents with PDP in LTC between 01/01/13 and 06/30/16 were identified with ≥1 claim of psychosis, hallucinations, or delusions after PD diagnosis. Treatment patterns were evaluated during the 12 months post index. We identified 864 PDP residents: 408 (47.2%) on AP therapy and 456 (52.8%) on no AP therapy. A total of 335 residents (82.1%) continued, 13 (3.2%) discontinued, 11 (2.7%) switched, and 49 (12.0%) augmented (used ≥2 APs) their index AP therapy. Based on the multivariate regression analysis, younger age, male gender, anemia, anxiolytic use or anxiety, sedatives/hypnotic use, bladder disorders including urinary tract infections, coronary conditions, diabetes, hypertension, and dementia were associated with a higher likelihood of treatment change. Understanding the factors associated with treatment change may inform ways to improve management of PDP in the U.S. LTC setting.

Time to re-engage psychiatric drug discovery by strengthening confidence in preclinical psychopharmacology

BACKGROUND

There is urgent need for new medications for psychiatric disorders. Mental illness is expected to become the leading cause of disability worldwide by 2030. Yet, the last two decades have seen the pharmaceutical industry withdraw from psychiatric drug discovery after costly late-stage trial failures in which clinical efficacy predicted pre-clinically has not materialised, leading to a crisis in confidence in preclinical psychopharmacology.

METHODS

Based on a review of the relevant literature, we formulated some principles for improving investment in translational neuroscience aimed at psychiatric drug discovery.

RESULTS

We propose the following 8 principles that could be used, in various combinations, to enhance CNS drug discovery: (1) consider incorporating the NIMH Research Domain Criteria (RDoC) approach; (2) engage the power of translational and systems neuroscience approaches; (3) use disease-relevant experimental perturbations; (4) identify molecular targets via genomic analysis and patient-derived pluripotent stem cells; (5) embrace holistic neuroscience: a partnership with psychoneuroimmunology; (6) use translational measures of neuronal activation; (7) validate the reproducibility of findings by independent collaboration; and (8) learn and reflect. We provide recent examples of promising animal-to-human translation of drug discovery projects and highlight some that present re-purposing opportunities.

CONCLUSIONS

We hope that this review will re-awaken the pharma industry and mental health advocates to the opportunities for improving psychiatric pharmacotherapy and so restore confidence and justify re-investment in the field.

Naloxone Alleviate the Severity of Delirium in Hospitalized Patients With Parkinsonism: Three Case Reports

Purpose: Delirium is common in geriatric with Parkinson's disease (PD). Treatments for delirium have generally been neuroleptics; however, antipsychotics have potential effect to block striatal dopamine D2 receptors and worsen symptom of parkinsonism. We explored whether naloxone can alleviate delirium in PD and other forms of parkinsonism. Patients and Methods: Patients with parkinsonism who met the delirium criteria of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) received naloxone infusions once or twice daily. Treatment effects were evaluated by the delirium rating scale-revised 98 (DRS-R98), including non-cognitive and cognitive subscales; the Richmond agitation-sedation scale (RASS); and the mini mental status examination (MMSE). Results: Two patients with primary parkinsonism, one with vascular PD were observed. The daily dose of naloxone was 2.08 ± 0.64 mg (range: 1-4 mg). Medication time last from 1 h to 7 days without side effects observed. Following with naloxone infusions, DRS-R98 scores decreased within 12 h and MMSE scores increased. The psychotic symptoms, disorientation, and attention deficits were alleviated significantly, while RASS scores decreased with naloxone treatment. Conclusion: Naloxone alleviated psychotic symptoms, improved cognitive dysfunction, and irritability in patients with delirium in the context of PD. The preliminary findings point out that the opioid system may be involved in the pathophysiology of delirium, which may be one of potential treat targets for delirium of PD.

Cyclodextrin polymers as efficient adsorbents for removing toxic non-biodegradable pimavanserin from pharmaceutical wastewaters

Presence of even small amount of active pharmaceutical ingredients in the environment carries risks to human and animal health, presenting an important issue. The paper presents issues related to the new drug - pimavanserin (PMV). Biological treatment efficiency of pimavanserin (PMV) was evaluated using lab-scale Sequencing Batch Reactor (SBR). It has been shown to have a negative effect on aquatic organisms by classifying it as a toxic compound (EC₅₀ = 8 mgL^-1). The level of biological degradation of PMV was insufficient (37%) and intensively foam formation caused operational problems. For this reason, in this study polymers based on cyclodextrins (CDs) were synthesized and used as adsorbents alternative to active carbons to effectively separate PMV from real industrial waste streams. Crosslinked β- and γ-CD polymers (β- and γ-NS), obtained in reaction with 1,1'-carbonyldiimidazole (CDI), were fully characterized by physicochemical methods. The adsorption equilibrium data were interpreted using Freundlich and Langmuir models. The sorption process was fast (60 s) and the efficiency of PMV separation from model waste waters was 93% and 81% for β- and γ-NS, respectively. Maximum polymer capacity was found at 52.08 mg g^-1 for β-NS and 23.26 mg g^-1 for γ-NS. The interactions of PMV with CDs have been studied and indicate that major mechanism of the sorption is based on supramolecular interaction and capture to polymer network. Described biodegradable and reusable materials are perfect example of correctly selected adsorbent for separation of target substance from postproduction aqueous media.

A Stage-Based Approach to Therapy in Parkinson's Disease

Parkinson’s disease (PD) is a neurodegenerative disorder that features progressive, disabling motor symptoms, such as bradykinesia, rigidity, and resting tremor. Nevertheless, some non-motor symptoms, including depression, REM sleep behavior disorder, and olfactive impairment, are even earlier features of PD. At later stages, apathy, impulse control disorder, neuropsychiatric disturbances, and cognitive impairment can present, and they often become a heavy burden for both patients and caregivers. Indeed, PD increasingly compromises activities of daily life, even though a high variability in clinical presentation can be observed among people affected. Nowadays, symptomatic drugs and non-pharmaceutical treatments represent the best therapeutic options to improve quality of life in PD patients. The aim of the present review is to provide a practical, stage-based guide to pharmacological management of both motor and non-motor symptoms of PD. Furthermore, warning about drug side effects, contraindications, as well as dosage and methods of administration, are highlighted here, to help the physician in yielding the best therapeutic strategies for each symptom and condition in patients with PD.

Current treatment of behavioral and cognitive symptoms of Parkinson's disease

Cognitive and behavioral symptoms are common in Parkinson's disease, may occur even in the prodromal stages of the disease, worsen with disease progression, and surpass motor symptoms as the major factors affecting patient quality of life and caregiver burden. The symptoms may be caused by the disease pathology or they may represent adverse effects of treatment, or both etiological factors may contribute. Although many of these symptoms are related to dopaminergic dysfunction or dopaminergic medication, other neurotransmitters are involved as well. Behavioral symptoms including impulse control disorders, apathy, psychosis, as well as mild cognitive impairment and dementia are reviewed with a special focus on current treatment approaches.

Atypical antipsychotics for Parkinson's disease psychosis: a systematic review and meta-analysis

PURPOSE

To assess the present evidence regarding the efficiency, safety, and potential risks of pharmacotherapy used for Parkinson's disease psychosis (PDPsy) treatment.

PATIENTS AND METHODS

We searched the following databases: PubMed, the Cochrane Library, ISI Web of Science, and Embase using the following terms: atypical antipsychotics, pimavanserin, olanzapine, quetiapine, clozapine, Parkinson's disease and psychosis. We systematically reviewed all randomized placebo-controlled trials comparing an atypical antipsychotic with a placebo.

RESULTS

A total of 13 randomized placebo-controlled trials for a total 1142 cases were identified involving pimavanserin (n=4), clozapine (n=2), olanzapine (n=3), and quetiapine (n=4). For each atypical antipsychotic, a descriptive synthesis and meta-analyses was presented. Pimavanserin was associated with a significant improvement in psychotic symptoms compared to a placebo without worsening motor function. Clozapine was efficacious in alleviating psychotic symptoms and did not exacerbate motor function either. Quetiapine and Olanzapine did not demonstrate significant differences in reducing psychotic symptoms but may aggravate motor function.

CONCLUSIONS

There is strong evidence that pimavanserin is effective for the treatment of PDPsy. Clozapine is also recommended but should be used with caution due to its side effects. In the future, more well-designed randomized controlled trials (RCTs) are needed to confirm and update the findings reported in this meta-analysis.

Perspective on Pimavanserin and the SAPS-PD: Novel Scale Development as a Means to FDA Approval

In 2016, pimavanserin, a 5-hydroxytryptamine 2A inverse agonist, became the first U.S. Food and Drug Administration (FDA) approved medication for Parkinson disease psychosis (PDP) after demonstrating modest clinical improvement in a single positive trial as assessed by a novel PDP scale, the Scale for the Assessment of Positive Symptoms for Parkinson's Disease Psychosis (SAPS-PD). This followed three trials that demonstrated negative findings on established measures of psychosis widely used in PDP research, including the Brief Psychiatric Rating Scale, the Scale for the Assessment of Positive Symptoms, the Parkinson Psychosis Rating Scale, and the Clinical Global Impression-Severity Scale. This review article provides an overview of the scale construction of the SAPS-PD, a measure which has yet to be established as valid, reliable, or sensitive to change in PDP. Furthermore, this article reviews analyses completed by an FDA statistical reviewer that call into question whether pimavanserin demonstrated a clinically significant difference from placebo on the SAPS-PD. These findings underscore concerns regarding the clinical efficacy of pimavanserin.

Parkinson's disease: what the model systems have taught us so far

Parkinson's disease (PD) is a debilitating neurodegenerative disorder, for which people above the age of 60 show an increased risk. Although there has been great advancement in understanding the disease-related abnormalities in brain circuitry and development of symptomatic treatments, a cure for PD remains elusive. The discovery of PD associated gene mutations and environmental toxins have yielded animal models of the disease. These models could recapitulate several key aspects of PD, and provide more insights into the disease pathogenesis. They have also revealed novel aspects of the disease mechanism including noncell autonomous events and spreading of pathogenic protein species across the brain. Nevertheless, none of these models so far can comprehensively represent all aspects of the human disease. While the field is still searching for the perfect model system, recent developments in stem cell biology have provided a new dimension to modelling PD, especially doing it in a patient-specific manner. In the current review, we attempt to summarize the key findings in the areas discussed above, and highlight how the core PD pathology distinguishes itself from other neurodegenerative disorders while also resembling them in many aspects.

Treating Hallucinations and Delusions Associated With Parkinson's Disease Psychosis

PURPOSE OF REVIEW

We discuss features of Parkinson's disease psychosis (PDP) including symptomology and pathophysiology. Treatment options, including non-pharmacologic strategies, dose reduction of offending agents, and the addition of non-dopaminergic antipsychotics, are addressed. The efficacy of second-generation antipsychotics and novel agents is examined.

RECENT FINDINGS

Pimavanserin, a 5-HT_2A/C receptor inverse agonist with no other receptor activity, has shown efficacy and tolerability and is now FDA approved for PDP treatment. Research into novel targets is ongoing. PDP is a morbid complication of Parkinson's disease with complex incompletely understood mechanisms. Treatment is directed towards mitigation of psychosis without worsening of motor features.

Parkinson's disease psychosis: presentation, diagnosis and management

Parkinson's disease is a neurodegenerative disorder characterized by motor and nonmotor symptoms. Psychosis is a common feature of Parkinson's disease. Parkinson's disease psychosis (PDP) encompasses minor phenomena (illusions, passage hallucinations and presence hallucinations), visual and nonvisual hallucinations and delusions. PDP is associated with reduced function and quality of life. The initial management approach should focus on identification and treatment of any contributory medical factors, reduction or discontinuation of medications with potential to induce or worsen psychosis, nonpharmacological strategies and consideration of acetylcholinesterase inhibitor treatment in the setting of dementia. Pimavanserin, quetiapine and clozapine may all be considered for use in PDP. In this review, we discuss the presentation, diagnosis and management of PDP.