Pimavanserin (ACP-103; BVF-036), sold under the brand name Nuplazid, is an

atypical antipsychotic The atypical antipsychotics (AAP), also known as second generation antipsychotics (SGAs) and serotonin–dopamine antagonists (SDAs), are a group of antipsychotic drugs (antipsychotic drugs in general are also known as major tranquilizers and ne ...

which is approved for the treatment of

Parkinson's disease Parkinson's disease (PD), or simply Parkinson's, is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. The symptoms usually emerge slowly, and as the disease worsens, non-motor symptoms becom ...

psychosis Psychosis is a condition of the mind that results in difficulties determining what is real and what is not real. Symptoms may include delusions and hallucinations, among other features. Additional symptoms are incoherent speech and behavior ...

and is also being studied for the treatment of Alzheimer’s disease psychosis,

schizophrenia Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social wit ...

, agitation, and

major depressive disorder Major depressive disorder (MDD), also known as clinical depression, is a mental disorder characterized by at least two weeks of pervasive low mood, low self-esteem, and loss of interest or pleasure in normally enjoyable activities. Intro ...

. Unlike other

antipsychotic Antipsychotics, also known as neuroleptics, are a class of psychotropic medication primarily used to manage psychosis (including delusions, hallucinations, paranoia or disordered thought), principally in schizophrenia but also in a range of ...

s, pimavanserin is not a dopamine receptor antagonist.

Pharmacology

Pharmacodynamics

Pimavanserin acts as an inverse agonist and antagonist at serotonin 5-HT_2A receptors with high binding affinity ( K_i 0.087 nM) and at serotonin 5-HT_2C receptors with lower binding affinity (K_i 0.44 nM). Pimavanserin shows low binding to σ₁ receptors (K_i 120 nM) and has no appreciable affinity (K_i >300 nM) to serotonin 5-HT_2B, dopamine (including D₂), muscarinic acetylcholine,

histamine Histamine is an organic nitrogenous compound involved in local immune responses, as well as regulating physiological functions in the gut and acting as a neurotransmitter for the brain, spinal cord, and uterus. Since histamine was discovered ...

, or adrenergic receptors, or to calcium channels. Pimavanserin has a unique

mechanism of action In pharmacology, the term mechanism of action (MOA) refers to the specific biochemical interaction through which a drug substance produces its pharmacological effect. A mechanism of action usually includes mention of the specific molecular targ ...

relative to other antipsychotics, behaving as a selective inverse agonist of the serotonin 5-HT_2A receptor, with 40-fold selectivity for this site over the 5-HT_2C receptor and no significant

affinity Affinity may refer to: Commerce, finance and law * Affinity (law), kinship by marriage * Affinity analysis, a market research and business management technique * Affinity Credit Union, a Saskatchewan-based credit union * Affinity Equity Par ...

or activity at the 5-HT_2B receptor or

dopamine receptor Dopamine receptors are a class of G protein-coupled receptors that are prominent in the vertebrate central nervous system (CNS). Dopamine receptors activate different effectors through not only G-protein coupling, but also signaling through diffe ...

History

Development

Pimavanserin was developed by Acadia Pharmaceuticals. Pimavanserin is expected to improve the

effectiveness Effectiveness is the capability of producing a desired result or the ability to produce desired output. When something is deemed effective, it means it has an intended or expected outcome, or produces a deep, vivid impression. Etymology The ori ...

and

side effect In medicine, a side effect is an effect, whether therapeutic or adverse, that is secondary to the one intended; although the term is predominantly employed to describe adverse effects, it can also apply to beneficial, but unintended, consequence ...

profile of antipsychotics. The results of a clinical trial examining the efficacy, tolerability and safety of adjunctive pimavanserin to

risperidone Risperidone, sold under the brand name Risperdal among others, is an atypical antipsychotic used to treat schizophrenia and bipolar disorder. It is taken either by mouth or by injection (subcutaneous or intramuscular). The injectable versions ...

and

haloperidol Haloperidol, sold under the brand name Haldol among others, is a typical antipsychotic medication. Haloperidol is used in the treatment of schizophrenia, tics in Tourette syndrome, mania in bipolar disorder, delirium, agitation, acute psychosi ...

were published in November 2012, and the results showed that pimavanserin potentiated the antipsychotic effects of subtherapeutic doses of

and improved the tolerability of

treatment by reducing the incidence of

extrapyramidal symptoms Extrapyramidal symptoms (EPS) are symptoms that are archetypically associated with the extrapyramidal system of the brain's cerebral cortex. When such symptoms are caused by medications or other drugs, they are also known as extrapyramidal side ...

. The drug met expectations for a Phase III

clinical trial Clinical trials are prospective biomedical or behavioral research studies on human participants designed to answer specific questions about biomedical or behavioral interventions, including new treatments (such as novel vaccines, drugs, diet ...

for the treatment of

, and has completed Phase II trials for adjunctive treatment of

alongside an

medication. On September 2, 2014, the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respon ...

granted

Breakthrough Therapy Breakthrough therapy is a United States Food and Drug Administration designation that expedites drug development that was created by Congress under Section 902 of the 9 July 2012 Food and Drug Administration Safety and Innovation Act. The FDA's "br ...

status to Acadia's New Drug Application for pimavanserin.

FDA Approval

On April 29, 2016 Nuplazid (pimavanserin) was approved by the

FDA The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food ...

for the treatment of hallucinations and delusions associated with Parkinson’s disease psychosis. The non-binding advisory panel recommendation of 12-to-2 in support of approval that preceded the FDA approval action noted that the drug met an important need, despite its only providing modest benefits and posing serious safety issues. On June 29, 2018 the FDA approved new dosages of pimavanserin to treat hallucinations and delusions associated with Parkinson’s disease psychosis. A 34 mg capsule and 10 mg tablet formulation were approved. Previously, patients were required to take two 17 mg tablets to achieve the recommenced 34 mg dose per day. The 10 mg dose is indicated for patients also taking CYP3A4 inhibitors (eg. ketoconazole).

HARMONY-Trial

In a phase 3, double-blind, randomized, placebo-controlled trial (ClinicalTrials.gov number NTC03325556) pimavanserin was applicated in patients with dementia-related psychosis. The dementia was caused by Alzheimer's disease, dementia with Lewy bodies, frontotemporal dementia, Parkinson's disease with dementia, or

vascular dementia Vascular dementia (VaD) is dementia caused by problems in the supply of blood to the brain, typically a series of minor strokes, leading to worsening cognitive abilities, the decline occurring piecemeal. The term refers to a syndrome consisti ...

. The trial was stopped early for efficacy. Patients treated with pimavanserin had a relapse in 13%, without in 28% (hazard ratio 0.35; 95% CI = 0.17-0.73; p = 0.005). Longer and larger trials are suggested.

Controversy

On April 9, 2018,

CNN CNN (Cable News Network) is a multinational cable news channel headquartered in Atlanta, Georgia, U.S. Founded in 1980 by American media proprietor Ted Turner and Reese Schonfeld as a 24-hour cable news channel, and presently owned by ...

reported that some in the FDA were concerned that Nuplazid was "risky" when it was approved and noted there have been a substantial number of deaths reported by those using the drug. The story further noted that the drug was approved based on a "six-week study of about 200 patients". The

began post-market monitoring of the drug to assess the validity of these claims. On September 20, 2018, the

stated their review "did not identify any new or unexpected safety findings with Nuplazid, or findings that are inconsistent with the established safety profile currently described in the drug label".

Research

Pimavanserin is under development for the treatment of

, agitation, and

psychiatric disorder A mental disorder, also referred to as a mental illness or psychiatric disorder, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning. Such features may be persistent, relapsing and remitt ...

s. As of March 2022, pimavanserin is in phase 3

s for major depressive disorder and schizophrenia, phase 2 trials for agitation, and phase 1 trials for psychiatric disorders. It was also under development for the treatment of

insomnia Insomnia, also known as sleeplessness, is a sleep disorder in which people have trouble sleeping. They may have difficulty falling asleep, or staying asleep as long as desired. Insomnia is typically followed by daytime sleepiness, low energy, ...

, drug-induced

akathisia Akathisia is a movement disorder characterized by a subjective feeling of inner restlessness accompanied by mental distress and an inability to sit still. Usually, the legs are most prominently affected. Those affected may fidget, rock back a ...

, and drug-induced

dyskinesia Dyskinesia refers to a category of movement disorders that are characterized by involuntary muscle movements, including movements similar to tics or chorea and diminished voluntary movements. Dyskinesia can be anything from a slight tremor of ...

, but development for these indications was discontinued.

References

External links

Nuplazid (pimavanserin) Official Site

Pimanvaserin - AdisInsight
{{Serotonin receptor modulators 5-HT2A antagonists Atypical antipsychotics Fluoroarenes Phenol ethers Piperidines Ureas Breakthrough therapy