Pimavanserin for psychosis in Parkinson's disease dementia: Subgroup analysis of the HARMONY Trial

INTRODUCTION

Pimavanserin is FDA-approved to treat Parkinson's disease (PD) psychosis. We analyzed the effect of pimavanserin on psychosis in the PD dementia (PDD) subgroup from the phase 3 HARMONY trial.

METHODS

This subgroup analysis included PDD patients enrolled in an international, multicenter, randomized discontinuation study of pimavanserin for dementia-related psychosis. PDD patients with moderate-to-severe psychosis, age 50-90 years, received pimavanserin 34 mg/day for 12 weeks (open-label period). Those with a sustained psychosis response to pimavanserin at weeks 8 and 12 were randomized during the double-blind period to continue pimavanserin or receive placebo. Primary efficacy endpoint was time to psychosis relapse as measured by the SAPS-H + D and CGI-I. Safety was assessed, as were effects on motor symptoms and cognitive abilities using the ESRS-A and MMSE.

RESULTS

392 patients were enrolled in HARMONY (mean age: 72.6 years; 38.8 % female): 59 had PDD; 49/59 remained on pimavanserin during the open-label period (safety analysis set), and 36/49 were randomized to pimavanserin (n = 16) or placebo (n = 20) in the double-blind phase (intent-to-treat analysis set). Risk of psychosis relapse was lower with pimavanserin 34 mg compared with placebo in the double-blind phase (HR = 0.052; 95 % CI 0.016-0.166; 1-sided nominal p < 0.001). During the open-label period, 46.9 % experienced a treatment-emergent adverse event; event incidence was similar across arms in the double-blind period. Pimavanserin did not adversely affect motor or cognitive function in either treatment phase.

CONCLUSIONS

Pimavanserin significantly reduced risk of psychosis relapse in patients with PDD, was well tolerated, and did not worsen motor or cognitive function.

Pimavanserin treatment increases plasma brain-derived neurotrophic factor levels in rats

Background

Pimavanserin, a serotonin 5HT-2A receptor inverse agonist is the first-line, FDA-approved treatment of hallucinations and delusions associated with Parkinson's Disease psychosis (PDP), which occurs in up to 50% of PD patients. The neurobiological mechanism underlying the therapeutic effectiveness of Pimavanserin in PDP remains unknown. Several earlier studies have shown that treatment with 5HT-2A antagonists and other drugs acting on the serotonergic system such as SSRIs increase Brain derived neurotrophic factor (BDNF) levels in rodents. BDNF is synthesized as the precursor proBDNF, that undergoes cleavage intra or extracellularly to produce a mature BDNF (mBDNF) protein. mBDNF is believed to play a key role in neuroplasticity and neurogenesis. The present study tested the hypothesis that treatment with Pimavanserin is associated with higher and sustained elevations of mBDNF.

Methods

Adult Sprague-Dawley male rats were treated with Pimavanserin, Fluoxetine or vehicle for 4 weeks (chronic) or 2 h (acute). BDNF levels were determined by enzyme-linked Immunosorbent assay (ELISA).

Results

We found significant increases in plasma mBDNF levels in rats following chronic Pimavanserin treatment, but not in Fluoxetine-treated rats. No significant changes in mBDNF levels were found in the prefrontal cortex or hippocampus following Pimavanserin or Fluoxetine treatment.

Conclusion

These findings suggest that increase in mBDNF levels could be a contributing mechanism for the neuroprotective potential of Pimavanserin.

Patients treated with pimavanserin or quetiapine for Parkinson's disease psychosis: analysis of health resource utilization patterns among Medicare beneficiaries

BACKGROUND

Pimavanserin (PIM) is the only FDA approved atypical antipsychotic (AAP) for the treatment of Parkinson's Disease Psychosis (PDP). However, other AAPs such as quetiapine (QUE) are used off-label in patients with PDP. Real-world comparative effects of PIM and QUE on health resource utilization (HCRU) may provide insights about their relative benefits.

OBJECTIVES

To examine annual HCRU among newly initiated PIM or QUE monotherapy among patients with PDP.

METHODS

Retrospective analysis of 100% Medicare (Parts A, B, and D) claims of patients with PDP during 01/01/13-12/31/19 was conducted. Treatment-naive patients with first prescription for PIM or QUE from 01/01/14-12/31/18 were selected if they had ≥12-months continuous monotherapy and had no prior AAP use for ≥12-month pre-index. Post-index 12-month HCRU was compared between 1:1 propensity score matched (PSM) PIM or QUE cohorts. HCRU outcomes included: rates of all-cause and psychiatric-related inpatient hospitalizations by stay-type [i.e., long-term stays (LT-stays), short-term stays (ST-stays), skilled nursing facility stays (SNF-stays)], outpatient hospitalizations, emergency room (ER) visits, and office visits. Relative risk (RR) and 95% confidence intervals (95% CI) are reported.

RESULTS

A total of 842 and 7,116 were treated with PIM and QUE, respectively. Mean age and gender distribution were similar among PIM (77.4 ± 7.2 years; 53% males) and QUE (78.1 ± 7.7 years; 54% males) cohorts, respectively. Among matched (n = 842) patients, those on PIM had significantly lower RR for all-cause: inpatient hospitalizations [RR 0.78 (95% CI: 0.70-0.87)], ST-stays [RR 0.75 (95% CI: 0.66-0.84)], SNF-stays [RR 0.64 (95% CI: 0.54-0.76)], and ER visits [RR 0.91 (95% CI: 0.84-0.97)] vs. QUE. PIM patients had slightly higher RR for all-cause office visits [RR 1.03 (95% CI: 1.01-1.05)] compared to QUE. All-cause LT-stays, and outpatient hospitalizations were not significant. The RR for psychiatric-related inpatient hospitalizations were lower for PIM vs. QUE: [0.63 (95% CI: 0.48-0.82)] ST-stays [0.61 (95% CI: 0.43-0.86)], SNF-stay [0.69 (95% CI: 0.47-1.02)], and ER visits [0.53 (95% CI: 0.37-0.76)].

CONCLUSIONS

Among patients with PDP newly treated with PIM monotherapy compared to newly treated QUE monotherapy, PIM users were nearly 22% and 37% less likely to have all-cause and psychiatric-related inpatient hospitalizations.

Non-clinical pharmacology and toxicology studies of LPM6690061, a novel 5-hydroxytryptamine (5-HT)2A receptor inverse agonist

LPM6690061 is a novel compound with 5-HT2A receptor antagonist and inverse agonist activities. To support the clinical trial and marketing application of LPM6690061, a series of pharmacology and toxicology studies have been conducted. In vitro and in vivo pharmacology studies showed that LPM6690061 had high inverse agonism and antagonism activities against human 5-HT2A receptors, and demonstrated significant antipsychotic-like effects in two rat models: the DOI-induced head-twitch model and the MK-801-induced hyperactivity model, which was more effective than the control drug pimavanserin. LPM6690061 did not have detectable side effects on the neurobehavioral activities and respiratory function in rats, or on the ECG or blood pressure in dogs at the doses of 2 and 6 mg/kg. The half maximal inhibitory concentration (IC50) of LPM6690061 for inhibiting hERG current was 1.02 μM. Three in vivo toxicology studies were conducted. In the single dose toxicity study in rats and dogs, the maximum tolerated dose of LPM6690061 was 100 mg/kg. In the 4-week repeat dose toxicity study in rats, the main detectable toxic reactions of LPM6690061 included moderate artery wall hypertrophy, minimal to mild mixed cell inflammation and increased macrophages in the lung, which generally recovered after a 4-week drug withdrawal period. In the 4-week repeat dose toxicity study in dogs, no detectable toxicity was observed. The doses of no-observed-adverse-effect-level (NOAEL) in rats and dogs were 10 mg/kg and 20 mg/kg, respectively. In conclusion, both in vitro and in vivo pharmacological and toxicological studies showed that LPM6690061 was a safe and efficacious 5-HT2A receptor antagonist/inverse agonist which supports the clinical development as a novel antipsychotic drug.

Clozapine: Efficacy for Parkinson Disease psychosis in patients refractory to pimavanserin

Pimavanserin is the only approved drug for Parkinson's disease psychosis (PDP) and is an increasingly used therapy where available. Clozapine has proven efficacy for PDP but is much less commonly used secondary to frequent blood tests to monitor for agranulocytopenia. We identified 27 patients with PDP (72 ± 7.3 years, 11 (41%) female), with an inadequate response to pimavanserin, who subsequently started clozapine. The final mean daily dose of clozapine was 49.5 mg [range 25-100] at night, and mean duration of follow-up was 17 months [range: 2-50 months]. Patients reported clozapine to be markedly effective in 11 (41%), moderately effective in 6 (22%), somewhat effective in 5 (18%). No patient reported that it was ineffective, but 5 (19%) had inadequate follow-up. Clozapine should be considered in pimavanserin refractory psychosis.

Pimavanserin reverses multiple measures of anxiety in a rodent model of post-traumatic stress disorder

Pimavanserin is a highly selective 5-HT_2A inverse agonist in current medical use. Prior studies suggest that 5-HT_2A serotonin receptors may play a role in anxiety and emotional memory. Therefore, pimavanserin was tested in a rat model of PTSD to determine whether it might ameliorate PTSD-like symptoms. The lifetime prevalence of PTSD is estimated to be 125% higher in women than men. Consequently, in an effort to create a robust model of PTSD that was more representative of human PTSD prevalence, 20-week old female rats of the emotionally hyperreactive Lewis strain were used for these studies. The rats were single-housed and exposed twice to restraint stress coupled with predator odor or to a sham-stressed condition. Twenty days after the second stress or sham-stress exposure, rats were injected with saline alone or with 0.3 or 1.0 mg/kg pimavanserin, doses that were confirmed to substantially block 5-HT_2A receptor activity in this study without causing any non-specific behavioral or adverse effects. One hour later, rats were tested for anxiety through acoustic startle response, the elevated plus-maze and three parameters of open field behavior. Five days later, blood was sampled for plasma corticosterone. The stressed/saline-injected rats had higher anxiety scores and corticosterone levels than sham-stressed/saline-injected rats. Pimavanserin significantly and generally dose-dependently reversed these persistent stress effects, but had no significant effect on the behavioral measures in normal, non-stressed rats. These results, consistent with a role for the 5-HT_2A receptor, suggest that pimavanserin might have potential to reduce some consequences of traumatic stress.

Psychotic Disorders in the Elderly: Diagnosis, Epidemiology, and Treatment

This review covers the latest advances in our understanding of psychosis in the elderly population with respect to diagnosis, epidemiology, and treatment. Major topics of discussion include late life psychiatric disorders such as schizophrenia, schizoaffective disorder, and delusional disorder as well as dementia-related psychosis. Clinical differences between early-onset and late-onset disorders are reviewed in terms of prevalence, symptomatology, and approach to treatment. Newly revised research and clinical criteria for dementia-related psychosis are referenced. The evidence base for emerging therapies including citalopram and pimavanserin in relation to conventional therapies such as atypical antipsychotics are discussed..

Atypical antipsychotic use and mortality risk in Parkinson disease

INTRODUCTION

Dopamine receptor blocking atypical antipsychotic (DRB-AAP) use has previously been associated with increased adverse effects and mortality risk among persons with Parkinson disease (PD). Pimavanserin, the only AAP indicated for PD psychosis in the U.S., is a serotonin receptor inverse agonist/antagonist with no known DRB activity. Early observational data have reported inconsistent findings regarding mortality risk associated with pimavanserin. The objective of this study was to estimate all-cause mortality risks of pimavanserin as compared to DRB-AAPs.

METHODS

We conducted a retrospective cohort study using a large U.S. commercial insurance database. Cox proportional hazards models were used to compare all-cause mortality risks between propensity score-matched groups of PD patients who were new users of pimavanserin or a DRB-AAP, further dividing DRB-AAPs into preferred (quetiapine, clozapine) and non-preferred (other remaining AAPs).

RESULTS

We identified 775, 4,563, and 1,297 individuals on pimavanserin, preferred, and non-preferred DRB-AAPs, respectively. There was no difference in mortality risk for pimavanserin vs. preferred DRB-AAPs [adjusted hazard ratio (aHR) 0.99, 95% CI: 0.81-1.20], or pimavanserin vs. non-preferred DRB-AAPs (aHR 0.98, 95% CI: 0.79-1.22) in intention-to-treat analyses.

CONCLUSION

Mortality risk among PD patients using AAPs did not differ by antipsychotic drug categorization based on mechanism of action. Research on the comparative efficacy and morbidity of AAPs, and the mortality associated with psychosis itself is needed to guide clinical decision-making in the PD population.

Dementia Is More Than Memory Loss: Neuropsychiatric Symptoms of Dementia and Their Nonpharmacological and Pharmacological Management

Neuropsychiatric symptoms of dementia (NPS) are a group of noncognitive symptoms that occur in over 90% of individuals with dementia. NPS seem to result from a complex interaction among various biological, psychosocial, and environmental factors, and they are associated with greater morbidity and mortality, higher caregiver burden and burnout, high risk of nursing home placement, and increased cost of care for patients with dementia. Use of standardized assessment tools like the Neuropsychiatric Inventory can assist with qualifying and quantifying NPS. In this review, the authors evaluate the evidence for efficacy and safety of nonpharmacological and pharmacological interventions for treating NPS, mostly based on published meta-analyses. Commonly prescribed medications include atypical antipsychotics, acetylcholinesterase inhibitors, memantine, antidepressants, and mood stabilizers. There are also limited data on cannabinoids, repetitive transcranial magnetic stimulation, and ECT in individuals with NPS. Available evidence indicates that several nonpharmacological interventions are beneficial in the management of NPS and are recommended as first-line treatments. Pharmacotherapy should be reserved for the treatment of more severe or refractory NPS or where nonpharmacological management is not feasible. Atypical antipsychotics have shown mostly modest benefit in reducing NPS, and their use is limited by their adverse effect profiles. Recent investigations suggest potential strategies for preventing or at least reducing the risk of dementia and NPS. The authors conclude with brief guidelines for clinical practice as well as future research.

Screening, Diagnosis, and Management of Parkinson's Disease Psychosis: Recommendations From an Expert Panel

INTRODUCTION

Hallucinations and delusions present with psychosis are debilitating non-motor symptoms of Parkinson's disease, with a prevalence of up to 50-70% at some point during the course of the disease. Often patients and caregivers do not report the presence of hallucinations or delusions unless specifically questioned. A panel of experts in neurology and geriatric psychiatry convened to develop a simple screening tool and guidance on diagnosis and treatment of Parkinson's disease psychosis (PDP).

METHODS

The working group reviewed literature for existing PDP guidelines on diagnosis and management and identified gaps in recommendations. The group discussed and developed a screening tool and treatment guidance that addressed the gaps in existing methodology based on their clinical experience.

RESULTS

The proposed screening tool consists of two parts: (1) a brief pre-visit screening portion to be completed by the patient and caregiver, and (2) a clinician portion to be completed via clinical interview of the patient and caregiver. If psychotic symptoms are present, an appropriate treatment plan is developed for PDP based on evaluation.

CONCLUSIONS

This simple screening tool and treatment guidance offers a practical clinical approach for clinicians in the diagnosis and management of PDP.

Pimavanserin in the Treatment of Parkinson's Disease Psychosis: Meta-analysis and Meta-regression of Randomized Clinical Trials

BACKGROUND

Up to 60 percent of patients with Parkinson's disease (PD) develop Parkinson's disease psychosis (PDP). PDP is associated with a significant economic burden. The management of PDP has been divided into two approaches-one focuses on decreasing the doses of anti-Parkinsonian medications and the other involves prescribing atypical antipsychotics. Of these atypical antipsychotics, pimavanserin is United States (US) Food and Drug Administration (FDA)-approved specifically for the treatment of PDP.

OBJECTIVE

The goal was to evaluate the safety and efficacy of pimavanserin in the treatment of PDP based on data from randomized clinical trials.

METHODS

All the articles, which assessed pimavanserin's effect on the treatment of PDP, were retrieved from Google Scholar, PubMed, and abstracts from annual scientific sessions. The data on dose, therapy duration, patient numbers, and study duration were collected. These data were analyzed with random effect modeling using the inverse variance method and the Mantel-Haenszel method.

RESULTS

Four studies comparing pimavanserin to a placebo provided data on 680 patients (263 placebo, 417 pimavanserin). Treatment with pimavanserin was associated with a significant reduction in scores using the Scale of Assessment of Positive Symptoms, Hallucinations, and Delusion (SAPS-H+D) (mean difference [MD]: -1.55 [-2.71, -0.379], p=0.009). The groups had similar composite scores for Unified Parkinson's Disease Rating Scale II and III (UPDRS II and III) (MD: 0.093 [-1.28, 1.46], p=0.89). Interestingly, pimavanserin was protective against orthostatic hypotension (risk ratio: 0.33 [0.30, 0.37], p<0.001). All other adverse events were similarly distributed across both groups.

CONCLUSION

There was a significant improvement in psychosis symptoms in patients with PD who took pimavanserin. Pimavanserin was also shown to be protective against orthostatic hypotension.

New and emerging treatments for schizophrenia: a narrative review of their pharmacology, efficacy and side effect profile relative to established antipsychotics

Schizophrenia is associated with substantial unmet needs, highlighting the necessity for new treatments. This narrative review compares the pharmacology, clinical trial data and tolerability of novel medications to representative antipsychotics. Cariprazine, brexpiprazole and brilaroxazine are partial dopamine agonists effective in acute relapse. Lumateperone (serotonin and dopamine receptor antagonist) additionally benefits asocial and depressive symptoms. F17464 (D3 antagonist and 5-HT1A partial agonist) has one positive phase II study. Lu AF35700 (dopamine and serotonin receptor antagonist) was tested in treatment-resistance with no positive results. Pimavanserin, roluperidone, ulotaront and xanomeline do not act directly on the D2 receptor at clinical doses. Initial studies indicate pimavanserin and roluperidone improve negative symptoms. Ulotaront and xanomeline showed efficacy for positive and negative symptoms of schizophrenia in phase II trials. BI 409306, BI 425809 and MK-8189 target glutamatergic dysfunction in schizophrenia, though of these only BI 425809 showed efficacy. These medications largely have favourable cardiometabolic side-effect profiles. Overall, the novel pharmacology, clinical trial and tolerability data indicate these compounds are promising new additions to the therapeutic arsenal.

Pimavanserin, a 5-hydroxytryptamine 2A receptor inverse agonist, reverses prepulse inhibition deficits in the nucleus accumbens and ventral hippocampus

Prepulse inhibition (PPI) is disrupted in many neuropsychiatric diseases. Although the inverse agonist of the 5-hydroxytryptamine 2A (5-HT2A) receptors, pimavanserin, alleviates PPI deficits in rodents, the precise mechanisms and critical brain areas in the reversal effect of 5-HT2A receptor inverse agonists remain unclear. The present study aimed to investigate the critical brain areas responsible for the reversal effect of the 5-HT2A receptor inverse agonist on PPI deficits in male mice. The results showed that intraperitoneal administration of pimavanserin was found to improve normal PPI behavior and reverse PPI deficits elicited by the dopamine D1/D2 receptor nonselective agonist, pergolide. Further, local infusion of pimavanserin into the nucleus accumbens and ventral hippocampus reversed PPI deficits, whereas the same manipulation in the medial prefrontal cortex or ventral tegmental area did not reverse PPI deficits. Overall, the nucleus accumbens and ventral hippocampus are the critical brain areas responsible for the reversal effect of 5-HT2A inverse agonists on PPI deficits. Such findings contribute to the extensive exploration of the accurate molecular and neural mechanisms underlying the antipsychotic effects of 5-HT2A receptor inverse agonists, especially the neural circuits modulated by 5-HT2A receptor activity.

Pimavanserin augments the efficacy of atypical antipsychotic drugs in a mouse model of treatment-refractory negative symptoms of schizophrenia

Negative symptoms are a core, pervasive, and often treatment-refractory phenotype of schizophrenia, one which contributes to poor functional outcome, ability to work, pursue educational goals, and quality of life, as well as caretaker burden. Improvement of negative symptoms in some patients with schizophrenia has been reported with some atypical antipsychotic drugs [AAPDs], but improvement is absent in many patients and partial in others. Therefore, more effective treatments are needed, and better preclinical models of negative symptoms are needed to identify them. Sub-chronic [sc] treatment of rodents with phencyclidine [PCP], a noncompetitive N-methyl-d-aspartate [NMDAR] antagonist, produces deficits in social interactions [SI] that have been widely studied as a model of negative symptoms in schizophrenia. Acute restraint stress [ARS] also provides a model of treatment-refractory negative symptoms [TRS] to AAPDs. By themselves, in sc-PCP mice, the AAPDs, risperidone, olanzapine, and aripiprazole, but not the selective 5-HT_2AR inverse agonist, pimavanserin [PIM], rescued the SI deficit in sc-PCP mice, as did the combination of PIM with sub-effective doses of each of these AAPDs. These three AAPDs alone did not rescue SI deficit in sc-PCP+2h-ARS mice, indicating these mice were treatment refractory. However, co-administration of PIM with any of the AAPDs significantly restored SI in these mice. PIM may be an effective adjunctive therapy for treating negative symptoms of schizophrenia in some patients who have failed to respond to AAPDs, but further studies are needed.

New Antipsychotic Medications in the Last Decade

PURPOSE OF REVIEW

Over the last ten years, the treatment of psychosis has seen a near explosion of creative development in both novel agents and new delivery modalities. The current review summarizes these developments over the past decade (2011-2020). We performed a systematic review utilizing PubMed and PsychInfo with the aim of identifying all the RCT and related analyses in adults with psychosis (schizophrenia and mania).

RECENT FINDINGS

We identified 11 significant developments: the introduction of new antipsychotics cariprazine, brexpiprazole, lumateperone, and pimavanserin; introduction of new delivery methods: subcutaneous long-acting risperidone, aripiprazole lauroxil, transdermal asenapine, and inhaled loxapine; and the introduction of new approaches such as olanzapine/samidorphan for olanzapine-associated weight gain, examination of the TAAR1 agonist SEP 363,856 as a test of concept, and the combination of Xanomeline/Trospium, an M₁ and M₄ muscarinic receptor agonist in conjunction with a peripheral anticholinergic. Last decade has seen a tremendous development in second-generation antipsychotics which provides unprecedented treatment options for clinicians in treating psychosis.

The protective effects of Pimavanserin against cerebral ischemia-induced brain injury

The integrity of the blood-brain barrier (BBB) is mainly maintained by the brain vascular endothelial cells and the tight junctions amongst them. Pimavanserin is a novel agent approved for the treatment of Parkinson’s disease and exerts neuroprotective properties. The present study aims to explore the possibility that Pimavanserin might be an effective agent used for the treatment of cerebral ischemia stroke. Middle cerebral artery occlusion (MCAO) was established in mice, and oxygen-glucose deprivation/reoxygenation (OGD/R) was established in brain bEND.3 endothelial cells. Mice were randomly divided into four groups: (1) Sham operation group; (2). Pimavanserin (1 mg/kg); (3). MCAO; (4). Pimavanserin+ MCAO. We found that compared to the Sham group, the elevated neurological deficit score and brain water content increased production of inflammatory factors, increased BBB permeability, and downregulated Claudin 5 expression were observed in the MCAO group and were all dramatically reversed by the administration of Pimavanserin. Brain bEND.3 endothelial cells were treated with Pimavanserin before the exposure to OGD/R. The significantly increased lactate dehydrogenase (LDH) release, declined cell viability, increased endothelial permeability, downregulated Claudin 5 and Krüppel-like factors 6 (KLF6) were observed in the OGD/R group and were all reversed by the introduction of Pimavanserin. Lastly, the effects of Pimavanserin on the expression level of Claudin 5 and endothelial permeability in OGD/R-challenged endothelial cells were both abolished by the knockdown of KLF6. Taken together, our data revealed that Pimavanserin protected against cerebral ischemia injury by regulating the BBB integrity in a KLF6-dependent manner.

Evaluating pimavanserin as a treatment for psychiatric disorders: A pharmacological property in search of an indication

Introduction: Pimavanserin is FDA-approved to treat hallucinations and delusions associated with Parkinson's disease psychosis. As a potent 5-HT_2A inverse agonist/antagonist, it could be efficacious in other psychiatric disorders. Recently, several studies have investigated this potential.Areas covered: The authors review the efficacy and adverse effects of pimavanserin for hallucinations in dementia, major depression, and schizophrenia.Expert opinion: Two controlled studies suggest pimavanserin has potential as a treatment for hallucinations in dementia. In patients with depression who did not respond to antidepressant treatment, pimavanserin augmentation was efficacious in a phase 2 study. Pimavanserin augmentation also alleviated sexual side effects of SSRI and SSNI. However, Acadia Pharmaceuticals stated in a press release that it does not plan further antidepressant trials based on its phase 3 trial, which showed a nonsignificant trend toward an antidepressant effect. Since almost all existing antipsychotics fail to substantially benefit negative symptoms, better treatments are needed. Pimavanserin augmentation of antipsychotics did benefit negative symptoms (effect size≈0.2) but failed to reduce the total PANSS score significantly in two large, well-controlled double-blind studies. Pimavanserin has a good safety profile.

Low continuation of antipsychotic therapy in Parkinson disease - intolerance, ineffectiveness, or inertia?

Background

Antipsychotics are used in Parkinson disease (PD) to treat psychosis, mood, and behavioral disturbances. Commonly used antipsychotics differ substantially in their potential to worsen motor symptoms through dopaminergic receptor blockade. Recent real-world data on the use and continuation of antipsychotic therapy in PD are lacking. The objectives of this study are to (1) examine the continuation of overall and initial antipsychotic therapy in individuals with PD and (2) determine whether continuation varies by drug dopamine receptor blocking activity.

Methods

We conducted a retrospective cohort study using U.S. commercially insured individuals in Optum 2001–2019. Adults aged 40 years or older with PD initiating antipsychotic therapy, with continuous insurance coverage for at least 6 months following drug initiation, were included. Exposure to pimavanserin, quetiapine, clozapine, aripiprazole, risperidone, or olanzapine was identified based on pharmacy claims. Six-month continuation of overall and initial antipsychotic therapy was estimated by time to complete discontinuation or switching to a different antipsychotic. Cox proportional hazards models evaluated factors associated with discontinuation.

Results

Overall, 38.6% of 3566 PD patients in our sample discontinued antipsychotic therapy after the first prescription, 61.4% continued with overall treatment within 6 months of initiation. Clozapine use was too rare to include in statistical analyses. Overall therapy discontinuation was more likely for those who initiated medications with known dopamine-receptor blocking activity (adjusted hazard ratios 1.76 [95% confidence interval 1.40–2.20] for quetiapine, 2.15 [1.61–2.86] for aripiprazole, 2.12 [1.66–2.72] for risperidone, and 2.07 [1.60–2.67] for olanzapine), compared with serotonin receptor-specific pimavanserin. Initial antipsychotic therapy discontinuation also associated with greater dopamine-receptor blocking activity medication use – adjusted hazard ratios 1.57 (1.28–1.94), 1.88 (1.43–2.46), 2.00 (1.59–2.52) and 2.03 (1.60–2.58) for quetiapine, aripiprazole, risperidone, and olanzapine, respectively, compared with pimavanserin. Similar results were observed in sensitivity analyses.

Conclusions

Over one-third of individuals with PD discontinued antipsychotic therapy, especially if the initial drug has greater dopamine-receptor blocking activity. Understanding the drivers of antipsychotic discontinuation, including ineffectiveness, potentially inappropriate use, clinician inertia, patient adherence and adverse effects, is needed to inform clinical management of psychosis in PD and appropriate antipsychotic use in this population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-021-02265-x.

Pimavanserin Promotes Trophic Factor Release and Protects Cultured Primary Dopaminergic Neurons Exposed to MPP+ in a GDNF-Dependent Manner

Neurodegeneration and impaired neural development are a common feature of many neuropsychiatric disorders. Second-generation antipsychotics (SGAs) and certain atypical antidepressants display neuroprotective effects. Though these drugs interact with many molecular targets, a common shared attribute is high antagonist potency at 5-HT_2A receptors. Pimavanserin is a selective 5-HT_2A inverse agonist/antagonist that was recently FDA approved for treating hallucinations and delusions associated with Parkinson's disease. Unlike SGAs, pimavanserin lacks activity at other targets like dopamine, histamine, muscarinic, and adrenergic receptors. To investigate whether selective 5-HT_2A inverse agonists have neuroprotective properties, pimavanserin and another selective 5-HT_2A inverse agonist, M100907, were applied to primary cultures of dopaminergic neurons treated with 1-methyl-4-phenylpyridinium (MPP+). Both pimavanserin and M100907 protected dopaminergic neurons against MPP+-induced cell death. The neuroprotective effects of pimavanserin required signaling through the extracellular signal-regulated kinase 1/2 pathway, restored mitochondrial function, and reduced oxidative stress. Further investigation showed that pimavanserin promotes the release of brain-derived neurotrophic factor and glial-derived neurotrophic factor (GDNF) and that the neuroprotective effects of pimavanserin were blocked by antibodies to GDNF but not by anti-tyrosine receptor kinase B receptor antibodies. Thus, pimavanserin induces release of neurotrophic factors and protects dopaminergic neurons against MPP+ toxicity in a GDNF-dependent manner.

Development of an analytical method for the determination of pimavanserin and its impurities applying analytical quality by design principles as a risk-based strategy

Pimavanserin is an atypical antipsychotic indicated for the treatment of hallucinations and delusions associated with Parkinson's disease psychosis. As it is a relatively new drug on the market, limited number of pharmacokinetic information and analytical methods are available. This paper presents an ultra-high performance chromatography for the simultaneous determination of pimavanserin and its four process impurities. The method was developed applying analytical quality by design (AQbD) principles as a risk-based approach. Critical method attributes (CMAs) were selected as a resolution between the worst separated compounds (impurity B and impurity C), a duration of analysis defined by the retention time of the last eluting peak (impurity D), a capacity factor of the first eluted impurity (impurity A), a tailing factor and a theoretical plate number. Risk assessment in the early stage of method development pointed out critical method parameters (CMPs): column temperature, gradient time and pH-value of the mobile phase (water phase, eluent A). Design of experiments (DoE), using DryLab®4 software, was applied to evaluate the influence of CMPs on CMAs and to determine method operable design region (MODR). Based on the risk assessment and the results of robustness and precision tests, a control strategy with system suitability criteria was proposed. Developed method was validated according to ICH Q2 (R1) guideline with respect to the selectivity, LOD, LOQ, linearity, precision, accuracy, robustness and stability. A forced degradation study was performed to provide an evidence of the stability-indicating property of the method. Degradation products of pimavanserin were identified using ultra high-performance liquid chromatography coupled to high resolution mass spectrometry (UHPLC-qTOF). Additionally, potential degradation products were assessed in silico with the help of Zeneth® software and good agreement with experimentally identified degradation products was achieved. Main degradation products were formed during acid and base hydrolysis (m/z 223.16 [M+H]⁺ at RRT 0.37) and under oxidative stress conditions (m/z 444.26 [M+H]⁺ at RRT 0.57). The results revealed that the pimavanserin undergoes degradation through acid and base hydrolysis of urea and N-oxidation of aliphatic tertiary amine.

Pilot Study to Evaluate Pimavanserin for the Treatment of Motor and Behavioral Symptoms of Tourette Syndrome

Background

Pimavanserin is a serotonin 2A receptor inverse agonist and antagonist used for the treatment of hallucinations and delusions in Parkinson's disease psychosis. Numerous studies support a modulatory role of serotonin in Tourette syndrome (TS).

Objectives

To determine whether or not pimavanserin affects TS symptoms.

Methods

In this open-label study of TS adult patients, pimavanserin was titrated to 34 mg/day over 1 week and continued for an additional 7 weeks followed by a 2-week washout. Tic severity, the primary outcome measure, was assessed by the Yale Global Tic Severity Scale Total Tic Severity score (YGTSS-TTS). Secondary outcome measures included changes in the Yale-Brown Obsessive Compulsive Scale (Y-BOCS), the Tourette Syndrome Clinical Global Impression of Change (TS-CGIC), the Tourette Syndrome-Patient Global Impression of Impact (TS-PGII), and the Gilles de la Tourette Syndrome - Quality of Life scale (GTS-QOL).

Results

We enrolled 12 patients, but 2 dropped out after week 2 due to non-serious side effects. In the 10 patients, mean (standard deviation (SD)) age 34 (12.9) who completed the study the mean (SD) baseline YGTSS-TTS was 34 (9.3). This decreased by 3.6 (4.9) points at week 8, a 12% reduction in tic severity (P = 0.03). This improvement is small and may not be clinically important. Significant improvement was noted in the TS-CGIC, TS-PGII and GTS-QO. No serious adverse events were reported.

Conclusions

The results of this study suggest that pimavanserin is safe and associated with improvement in motor and non-motor TS symptoms. These findings warrant further study by a larger, placebo-controlled, trial.

5-HT2A and 5-HT2C receptors as potential targets for the treatment of nicotine use and dependence

Nicotine use and dependence, typically achieved through cigarette smoking, but increasingly through vape products, is the leading cause of preventable death today. Despite a recognition that many current smokers would like to quit, the success rate at doing so is low and indicative of the persistent nature of nicotine dependence and the high urge to relapse. There are currently three main forms of pharmacotherapy approved as aids to treat nicotine dependence: a variety of nicotine replacement products (NRT's), the mixed NA/DA reuptake inhibitor bupropion (Zyban®), and the preferential nicotinic α4β2 receptor agonist drug, varenicline (Chantix®); the latter being generally recognized to be the most effective. However, each of these approaches afford only limited efficacy, and various other pharmacological approaches are being explored. This chapter focusses on approaches targeted to the serotonin (5-HT) system, namely, selective serotonin reuptake inhibitors (SSRI's) which served a pioneer role in the investigation of serotoninergic modulators in human smoking cessation trials; and secondly drugs selectively interacting with the 5-HT2A and 5-HT2C receptor systems. From an efficacy perspective, measured as smoking abstinence, the 5-HT2A agonist psychedelics, namely psilocybin, seem to show the most promise; although as the article highlights, these findings are both preliminary and there are significant challenges to the route to approval, and therapeutic use of this class should they reach approval status. Additional avenues include 5-HT2C receptor agonists, which until recently was pioneered by lorcaserin, and 5-HT2A receptor antagonists represented by pimavanserin. Each of these approaches has distinct profiles across preclinical tests of nicotine dependence, and may have therapeutic potential. It is anticipated as diagnostic and predictive biomarkers emerge, they may provide opportunities for subject stratification and opportunities for personalizing smoking cessation treatment. The clinical assessment of SSRI, 5-HT2A and/or 5-HT2C receptor-based treatments may be best served by this process.

Pimavanserin, a 5HT2A receptor inverse agonist, rapidly suppresses Aβ production and related pathology in a mouse model of Alzheimer's disease

Amyloid-β (Aβ) peptide aggregation into soluble oligomers and insoluble plaques is a precipitating event in the pathogenesis of Alzheimer's disease (AD). Given that synaptic activity can regulate Aβ generation, we postulated that 5HT_2A -Rs may regulate Aβ as well. We treated APP/PS1 transgenic mice with the selective 5HT_2A inverse agonists M100907 or Pimavanserin systemically and measured brain interstitial fluid (ISF) Aβ levels in real-time using in vivo microdialysis. Both compounds reduced ISF Aβ levels by almost 50% within hours, but had no effect on Aβ levels in 5HT_2A -R knock-out mice. The Aβ-lowering effects of Pimavanserin were blocked by extracellular-regulated kinase (ERK) and NMDA receptor inhibitors. Chronic administration of Pimavanserin by subcutaneous osmotic pump to aged APP/PS1 mice significantly reduced CSF Aβ levels and Aβ pathology and improved cognitive function in these mice. Pimavanserin is FDA-approved to treat Parkinson's disease psychosis, and also has been shown to reduce psychosis in a variety of other dementia subtypes including Alzheimer's disease. These data demonstrate that Pimavanserin may have disease-modifying benefits in addition to its efficacy against neuropsychiatric symptoms of Alzheimer's disease. Read the Editorial Highlight for this article on page 560.

Effect of adjunctive pimavanserin on suicidal ideation in patients with major depression: Analysis of the CLARITY study

BACKGROUND

Up to 15% of patients with major depressive disorder (MDD) attempt suicide and up to 2% complete suicide. This was a post-hoc analysis aimed to evaluate the risk of suicide ideation and behavior associated with adjunctive pimavanserin treatment in adults with MDD.

METHODS

CLARITY was a randomized, double-blind, placebo-controlled study in patients with MDD and an inadequate response to a selective serotonin reuptake inhibitor (SSRI) or serotonin-norepinephrine reuptake inhibitor (SNRI). For this post-hoc analysis, the primary endpoint was mean change from baseline for HAMD item 3 (suicide). The incidence of suicidal ideation or behavior was also assessed from the Columbia-Suicide Severity Rating Scale (C-SSRS) and reports of adverse events.

RESULTS

During Stage 1, LS mean change for HAMD Item 3 was reduced from baseline at each week with pimavanserin with a significant difference between pimavanserin and placebo at Week 3 (p=0.012, effect size: 0.431). At any post-baseline assessment, suicidal ideation on the C-SSRS was reported in 28 (18.1%) of patients with placebo and 9 (17.3%) with pimavanserin during Stage 1 and in 7 (20.7%) with placebo and 4 (13.8%) with pimavanserin during Stage 2. No events of suicidal behavior were observed with either placebo or pimavanserin.

LIMITATIONS

The post hoc nature, exclusion of patients with any history of suicide from the primary study, and the small number of patients who demonstrated evidence of suicidal ideation.

CONCLUSIONS

Adjunctive pimavanserin was not associated with an increase in suicidal ideation in patients with MDD. Further study is needed to verify these results.

Pimavanserin in Alzheimer's Disease Psychosis: Efficacy in Patients with More Pronounced Psychotic Symptoms

BACKGROUND

Pimavanserin is a 5-HT2A receptor inverse agonist/antagonist and is approved in the United States for the treatment of hallucinations and delusions associated with Parkinson's disease psychosis.

OBJECTIVE

Evaluate the efficacy of pimavanserin on symptoms of psychosis in patients with Alzheimer's disease (AD).

DESIGN

Randomized, double-blind, placebo-controlled trial.

SETTING

Nursing home residents.

PARTICIPANTS

Patients with AD psychosis.

INTERVENTIONS

Pimavanserin 34 mg or placebo daily for 12 weeks.

MEASUREMENTS

The primary endpoint was mean change from baseline at Week 6 on the Neuropsychiatric Inventory-Nursing Home Version psychosis score (NPI-NH-PS). In the prespecified subgroup analysis, the mean change in NPI-NH-PS and the responder rates among those with baseline NPI-NH-PS ≥12 were evaluated.

RESULTS

Of 181 patients randomized (n=90 pimavanserin; n=91 placebo), 57 had baseline NPI-NH-PS ≥12 (n=27 pimavanserin; n=30 placebo). In this severe subgroup, large treatment effects were observed (delta=-4.43, Cohen's d=-0.73, p=0.011), and ≥30% improvement was 88.9% vs. 43.3% (p<0.001) and ≥50% improvement was 77.8% vs. 43.3% (p=0.008) for pimavanserin and placebo, respectively. The rate of adverse events (AEs) in the severe subgroup was similar between treatment groups, and urinary tract infection, fall, and agitation were most frequent. Serious AEs was similar with pimavanserin (17.9%) and placebo (16.7%) with fewer discontinuations due to AEs with pimavanserin (7.1%) compared to placebo (10.0%). Minimal change from baseline occurred for the mean MMSE score over 12 weeks.

CONCLUSIONS

Pimavanserin demonstrated significant efficacy in AD psychosis in patients with higher baseline severity of psychotic symptoms (NPI-NH-PS ≥12). Treatment with pimavanserin showed an acceptable tolerability profile.

Pimavanserin for the treatment of psychosis in Alzheimer’s disease: A literature review

BACKGROUND

Alzheimer’s disease (AD) is among the most prevalent forms of dementia in the world and neuropathological studies suggest similar high prevalence of mixed (AD + vascular) dementias. Approximately 25%-50% of individuals with AD develop psychosis sometime during their illness. The presence of psychosis in AD worsens outcomes. Currently there are no United States Food and Drug Administration (FDA) approved medications for the treatment of psychosis in AD. Pimavanserin, a novel atypical antipsychotic medication, was approved by the FDA for the treatment of hallucinations and delusions associated with Parkinson disease psychosis and is currently in clinical trials for the treatment of psychosis in AD.

AIM

To evaluate the existing literature regarding the use of pimavanserin for treating psychosis among individuals with AD.

METHODS

A literature review of clinical studies of pimavanserin treatment for psychosis in individuals with AD was performed using the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. Trials were identified by systematically searching PubMed, MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Web of Science, and Scopus through October 2019. The 5-point Jadad scoring system was used to assess the methodologic quality of the randomized placebo-controlled trials.

RESULTS

A total of 499 citations were retrieved and pooled in EndNote and de-duplicated to 258 citations. This set was uploaded to Covidence for screening. Two separate screeners (Srinivasan S and Tampi RR) evaluated the titles, abstracts, and full text of eligible articles. Of the identified 258 abstracts, 98 articles underwent full text review and 2 publications from 1 randomized controlled trial (RCT) were included in the final analysis. The quality of evidence was assessed to be of good methodologic quality, scoring 4 out of 5 using the 5-point Jadad questionnaire with the Jadad Scoring calculation. This systematic review found only one RCT that evaluated the use of pimavanserin for the treatment of psychosis among individuals with AD. This phase 2 trial resulted in two publications, the second of which was a subgroup analysis from the original study. The evidence from these two publications showed that pimavanserin improves psychotic symptoms among individuals with AD when compared to placebo at week 6.

CONCLUSION

Pimavanserin may be a pharmacologic consideration for the treatment for psychosis in AD. Additional RCTs are needed to assess the evidence of effectiveness before pimavanserin is considered a standard treatment.

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.

Pimavanserin exhibits serotonin 5-HT2A receptor inverse agonism for Gαi1- and neutral antagonism for Gαq/11-proteins in human brain cortex

Pimavanserin is claimed as the first antipsychotic drug that shows selectivity for serotonin 5-HT₂ receptors (5-HT₂Rs) and lacks of affinity for dopamine D₂ receptors (D₂Rs). Cell-based functional assays suggest that pimavanserin and antipsychotics with D₂R/5-HT₂R affinity could act as inverse agonists of 5-HT_2ARs. However, there is not evidence of such pharmacological profile in native brain tissue. 5-HT_2ARs are able to engage both canonical G_αq/11- and non-canonical G_αi1-proteins. In the present study, the response to pimavanserin of the 5-HT_2AR coupling to G_αq/11- and G_αi1-proteins was measured in membranes of postmortem human prefrontal cortex by antibody-capture [³⁵S]GTPγS binding scintillation proximity assays. Pimavanserin promoted a concentration-dependant inhibition of the 5-HT_2AR coupling to G_αi1-proteins whereas the response of G_αq/11-proteins was unaltered, suggesting inverse agonism and neutral antagonism properties, respectively. The inhibition was abolished in the presence of the selective 5-HT_2AR antagonist MDL-11,939 and was absent in brain cortex of 5-HT_2AR knock-out mice when compared to respective 5-HT_2AR wild-type animals. In conclusion, the results demonstrate the existence of constitutive 5-HT_2AR activity in human brain for the signalling pathway mediated by G_αi1-proteins. Pimavanserin demonstrates 5-HT_2AR functional selectivity and exhibits inverse agonist profile towards G_αi1-proteins, which is considered the effector pathway promoting hallucinogenic responses. In contrast, pimavanserin behaves as neutral antagonist on the 5-HT_2AR coupling to the canonical G_αq/11-protein pathway. The results strengthen the relevance of inverse agonism as potential mechanism of antipsychotic activity. Moreover, the existence of functional selectivity of 5-HT_2ARs for different G_α-proteins could contribute to better design of 5-HT_2AR-related antipsychotic drugs.

Treatment of psychosis in Parkinson's disease and dementia with Lewy Bodies: A review

There is a considerable overlap between Parkinson's Disease Dementia (PDD) and Dementia with Lewy Bodies (DLB). They present a challenge therapeutically, with regard to morbidity and mortality risk. In particular, symptoms of psychosis in these conditions augur a considerably increased burden. To date, there has been a myriad of prospective, retrospective and case studies examining the use of neuroleptics in the treatment of psychotic symptoms in PDD/DLB. Clozapine has the most robust evidence base however its use is limited by agranulocytosis risk and the associated need for frequent blood count monitoring. Quetiapine is more readily used, however, it has a more equivocal evidence base, in terms of efficacy. Other neuroleptics have thus far demonstrated mixed results with increased risk of extrapyramidal worsening. In addition to the atypical agents, the introduction of pimavanserin has provided another treatment option for Parkinson's Disease Psychosis (PDP), decreasing concern for deterioration in motor function. We await further research to confidently demonstrate its efficacy and safety in DLB psychosis. Cholinesterase inhibitors likely have a limited role in treating milder psychosis symptomatology in DLB and perhaps PDD. After review of the current literature for antipsychotic therapy in both PDD and DLB, we provide a logical framework for addressing psychotic symptoms in each condition.

Identification of a Serotonin 2A Receptor Subtype of Schizophrenia Spectrum Disorders With Pimavanserin: The Sub-Sero Proof-of-Concept Trial Protocol

Background

All current approved antipsychotic drugs against schizophrenia spectrum disorders share affinity for the dopamine receptor (D2R). However, up to one-third of these patients respond insufficiently, and in some cases, side-effects outweigh symptom reduction. Previous data have suggested that a subgroup of antipsychotic-naïve patients will respond to serotonin 2A receptor (2AR) blockade.

Aims

This investigator-initiated, translational, proof-of-concept study has overall two aims; 1) To test the clinical effectiveness of monotherapy with the newly approved drug against Parkinson's disease psychosis, pimavanserin, in antipsychotic-free patients with first-episode schizophrenia spectrum disorders; 2) To characterize the neurobiological profile of responders to pimavaserin.

Materials and Equipment

Forty patients will be enrolled in this 6-week open label, one-armed trial with the selective serotonin 2AR antagonist (pimavanserin 34 mg/day). At baseline, patients will undergo: positron emission tomography (PET) imaging of the serotonin 2AR using the radioligand [¹¹C]Cimbi-36; structural magnetic resonance imaging (MRI); MR spectroscopy of cerebral glutamate levels and diffusion tensor imaging; cognitive and psychopathological examinations; electrocardiogram, and blood sampling for genetic- and metabolic analyses.

Outcome Measures

The primary clinical endpoint will be reduction in the Positive and Negative Syndrome Scale (PANSS) positive score. Secondary clinical endpoints comprise multiple clinical ratings (positive and negative symptoms, depressive-, obsessive-compulsive symptoms, quality of life, social functioning, sexual functioning, and side-effects). PET, MRI, and cognitive parameters will be used for in-depth neuropsychiatric characterization of pimavanserin response.

Anticipated Results

Clinically, we expect pimavanserin to reduce psychotic symptoms with similar effect as observed with conventional antipsychotics, for which we have comparable historical data. We expect pimavanserin to induce minimal side-effects. Neurobiologically, we expect psychotic symptom reduction to be most prominent in patients with low frontal serotonin 2AR binding potential at baseline. Potential pro-cognitive and brain structural effects of pimavanserin will be explored.

Perspectives

Sub-Sero will provide unique information about the role serotonin 2AR in antipsychotic-free, first-episode psychosis. If successful, Sub-Sero will aid identification of a “serotonergic subtype” of schizophrenia spectrum patients, thereby promoting development of precision medicine in clinical psychiatry.

Clinical Trial Registration

ClinicalTrials, identifier NCT03994965.

Pimavanserin versus quetiapine for the treatment of psychosis in Parkinson's disease and dementia with Lewy bodies

INTRODUCTION

Psychosis is common among patients with Parkinson's disease (PD) and dementia with Lewy bodies (DLB). Limited data exist on the most effective therapies.

METHODS

Retrospective cohort study comparing patients with PD or DLB initiated on quetiapine or pimavanserin for psychosis. Primary outcome was time to discontinuation of pimavanserin or quetiapine using Kaplan-Meier survival analysis. We hypothesized the rate of antipsychotic discontinuation would be lower in the pimavanserin group. Subjects were included if the indication for treatment was psychosis and excluded if there was a history of major mental illness or no follow up data were available.

RESULTS

Forty-seven patients were included in the quetiapine cohort and 45 in the pimavanserin cohort. Patients in the pimavanserin cohort were more likely to have a diagnosis of DLB (33% vs. 11%, P = 0.01) and to have been prescribed an antipsychotic previously (62% vs. 6%, P < 0.01); otherwise, the groups were similar. Time to discontinuation analysis, which accounts for efficacy, safety and tolerability, revealed a lower early pimavanserin discontinuation rate and a higher late pimavanserin discontinuation rate (HR < 1 before day 43, HR > 1 after day 43; P = 0.04). There was no difference in mortality in the pimavanserin group compared to the quetiapine group (HR 0.37, 95% CI 0.06 to 2.45; P = 0.88). More individuals had a documented secondary indication for taking quetiapine than pimavanserin (38% vs. 4%; P = 0.001).

CONCLUSION

Accounting for efficacy, safety and tolerability, pimavanserin may be more clinically useful for promptly managing psychosis, while quetiapine may confer additional secondary benefits long-term.

Evidence for using pimavanserin for the treatment of Parkinson's disease psychosis

The aim of this editorial is to evaluate the evidence for using pimavanserin for the treatment of Parkinson's disease psychosis (PDP) from randomized controlled trials (RCTs). We only identified two published trials that evaluated the use of pimavanserin among individuals with PDP. Both studies found that pimavanserin improved psychotic symptoms among individuals with PDP when compared to placebo. Pimavanserin was fairly well tolerated in both studies and did not appear to cause significant sedation or worsen motor symptoms among individuals with PDP. However, given the limited data, additional confirmatory studies are required before pimavanserin can be considered as a first line agent for the treatment of psychotic symptoms among individuals with PD.

Successful treatment of clozapine-nonresponsive refractory hallucinations and delusions with pimavanserin, a serotonin 5HT-2A receptor inverse agonist

BACKGROUND

Clozapine was the widely accepted gold standard treatment for treatment resistant psychotic symptoms. Clozapine has efficacy of about 50% and some responding patients have to discontinue it due to serious adverse effects. The search for novel agents to use for clozapine-non-responders continues. One such possible agent is the non-dopaminergic antipsychotic pimavanserin, an inverse agonist of serotonin 5-HT2A receptors which was recently approved for the hallucinations and delusions of Parkinson's Disease Psychosis. We report here the successful results of using pimavanserin in patients with refractory hallucinations and delusions who failed to respond to clozapine. We also report similar results in refractory psychosis patients who did not receive clozapine.

METHODS

We present ten cases of patients with schizophrenia and schizoaffective disorder with refractory hallucinations and delusions who received a trial of pimavanserin when clozapine or multiple antipsychotics failed. Six of ten patients had not responded to a clozapine trial. The subjects' ages ranged between 21 and 77 years and were followed up for several months.

RESULTS

All 10 patients with refractory hallucinations and delusions showed marked response to pimavanserin 34 mg/day within 4-8 weeks, with continuation of the response for several months of follow-up. Improvements in negative symptoms and social functioning were also observed in several patients.

DISCUSSION

This series of 10 cases of patients with refractory psychosis who responded to pimavanserin is an important new finding that has never been reported before. Controlled studies comparing clozapine and pimavanserin in refractory schizophrenia are warranted to confirm these clinical observations.

Psychiatric commentary addressing the article titled "Guidance for switching from off-label antipsychotics to pimavanserin for Parkinson's disease psychosis: an expert consensus"

Pimavanserin is not curative, but can improve the quality of life remaining for the person with Parkinson's disease who typically has been suffering from this relentless neurodegenerative disease for years. Using pimavanserin effectively requires knowledge not only about the product itself, but also about the treatments pimavanserin is replacing.

Pimavanserin (Nuplazid™) for the treatment of Parkinson disease psychosis: A review of the literature

Introduction:

Pimavanserin (Nuplazid™) is an atypical antipsychotic currently indicated for the treatment of hallucinations and delusions associated with Parkinson disease psychosis. The antipsychotic effects of this new agent are believed to occur via selective inverse agonist activity at serotonin 5-HT_2a receptors.

Methods:

Study authors completed a literature review of 2 published randomized controlled trials of pimavanserin for the treatment of Parkinson disease psychosis. The Food and Drug Administration Briefing Document by the Psychopharmacologic Drugs Advisory Committee for the review of pimavanserin dated March 29, 2016, was reviewed for additional information on 2 unpublished trials.

Results:

Pimavanserin has demonstrated no worsening of motor symptoms of Parkinson disease, but only 1 of 4 trials has shown consistent statistically significant improvements in psychotic symptoms compared with placebo.

Discussion:

Options for the treatment of Parkinson disease psychosis are limited. The selective receptor profile of pimavanserin offers advantages for tolerability. Further studies are warranted to better provide clinicians and patients with information regarding the clinical utility of this agent.

Pimavanserin: A Novel Drug Approved to Treat Parkinson's Disease Psychosis

Objective: Pimavanserin is the first United States Food and Drug Administration (FDA)-approved treatment for Parkinson's disease psychosis (PDP). This article reviews the safety, efficacy, and pharmacology data for pimavanserin and its role in therapy. Method of Research: Initial literature sources were identified via MEDLINE search (1946-September 2016) of pimavanserin and ACP-103 (original molecular designation). Reference review and search of FDA.gov and clinicaltrials.gov yielded additional studies. English-language studies of pimavanserin for PDP were evaluated. Animal studies were excluded. Randomized, controlled trials (RCTs) were prioritized. Results: Four RCTs were identified. In each, pimavanserin was well-tolerated with few adverse effects and no worsening of motor symptoms. A Phase II trial displayed a nonsignificant trend toward Scale for Assessment of Positive Symptoms (SAPS) improvement (p=0.09), with significant benefits in secondary efficacy markers. However, two Phase III trials, including one that was terminated early, failed to show significant SAPS improvement. A third Phase III trial with an improved research design utilized a nine-item subset of the SAPS, the SAPS-PD, as the primary outcome and demonstrated that pimavanserin 40mg was effective in improving PDP compared to placebo (p=0.0014, effect size=0.50). Secondary outcomes were also significantly improved: Clinical Global Impression of Severity (CGI-S) (p=0.0007, effect size=0.52) and Clinical Global Impression of Improvement (CGI-I) (p=0.0011, effect size=0.51), caregiver burden (p=0.0016, effect size=0.50), nighttime sleep (p=0.0446, effect size=0.31), and daytime wakefulness (p=0.012, effect size=0.39). Conclusion: Evidence suggests pimavanserin attenuates PDP symptoms with few adverse effects and little risk of worsening motor function. With limited treatment options for PDP, pimavanserin represents an important therapeutic innovation.

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.

Development of a UPLC-MS/MS method for determination of pimavanserin tartrate in rat plasma: Application to a pharmacokinetic study

A simple, rapid and sensitive method based on an ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) has been developed and validated for the determination of pimavanserin in rat plasma. The analyte was extracted by protein precipitation with methanol and separated on an ACQUITY BEH C₁₈ column (100 × 2.1 mm, 1.7 µm; Waters, USA), with an isocratic elution of acetonitrile-water containing 10 mM ammonium acetate (70:30, v/v), at a flow rate of 0.2 mL/min for 2.5 min. The analyte and clarithromycin (the internal standard) were detected and quantified in positive ion mode using multiple reaction monitoring transitions at m/z 428.2 → 223.0 for pimavanserin and m/z 748.5 → 589.5 for clarithromycin. Relative coefficient (r) for the calibration curve was more than 0.9980. The intra-day and inter-day precisions (relative standard deviation, RSD%) were less than 13.3% and 10.5%, respectively, and the accuracy (relative error, RE%) was within ± 11.5%. The analytical method was successfully applied to a routine pharmacokinetic study of pimavanserin in rats after oral administration at the dose of 10 mg/kg.

Effects of 7-day repeated treatment with the 5-HT2A inverse agonist/antagonist pimavanserin on methamphetamine vs. food choice in male rhesus monkeys

BACKGROUND

Preclinical drug vs. food choice is an emerging group of drug self-administration procedures that have shown predictive validity to clinical drug addiction. Emerging data suggest that serotonin (5-HT)2A receptors modulate mesolimbic dopamine function, such that 5-HT2A antagonists blunt the abuse-related neurochemical effects of monoamine transporter substrates, such as amphetamine or methamphetamine. Whether subchronic 5-HT2A antagonist treatment attenuates methamphetamine reinforcement in any preclinical drug self-administration procedure is unknown. The study aim was therefore to determine 7-day treatment effects with the 5-HT2A inverse agonist/antagonist pimavanserin on methamphetamine vs. food choice in monkeys.

METHODS

Behavior was maintained under a concurrent schedule of food delivery (1g pellets, fixed-ratio 100 schedule) and intravenous methamphetamine injections (0-0.32 mg/kg/injection, fixed-ratio 10 schedule) in male rhesus monkeys (n=3). Methamphetamine choice dose-effect functions were determined daily before and during 7-day repeated pimavanserin (1.0-10mg/kg/day, intramuscular) treatment periods.

RESULTS

Under control conditions, increasing methamphetamine doses resulted in a corresponding increase in methamphetamine vs. food choice. Repeated pimavanserin administration failed to attenuate methamphetamine choice and produce a reciprocal increase in food choice in any monkey up to doses (3.2-10mg/kg) that suppressed rates of operant responding primarily during components where behavior was maintained by food pellets.

CONCLUSIONS

Repeated 5-HT2A receptor inverse agonist/antagonist treatment did not attenuate methamphetamine reinforcement under a concurrent schedule of intravenous methamphetamine and food presentation in nonhuman primates. Overall, these results do not support the therapeutic potential of 5-HT2A inverse agonists/antagonists as candidate medications for methamphetamine addiction.

Pimavanserin

Pimavanserin (ACP-103) is a selective inverse agonist of the 5-hydroxytryptamine 2A (5-HT2A) receptor intended to treat patients with Parkinson's disease psychosis (PDP). Currently there are no FDA-approved medications in the United States for the treatment of PDP, although on September 2, 2014, the United States Food and Drug Administration granted breakthrough therapy status to pimavanserin, highlighting the unmet need for therapeutics in this class. Most antipsychotic medications worsen motor dysfunction due to dopamine antagonism, and all carry a black box warning for an increased risk of mortality in elderly patients with dementia-related psychosis. Data from phase II and phase III clinical trials suggest that pimavanserin is a safe and effective treatment option for PDP. Trial results indicate a significant reduction in hallucinations and delusions in patients with PDP without worsening motor symptoms. Additional studies are ongoing for the treatment of Alzheimer's psychosis, schizophrenia and insomnia. Such promising outcomes warrant a review of the available literature regarding pimavanserin and its use in the treatment of PDP symptoms.