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Serotonin Inverse Agonist

Pimavanserin for Autism Spectrum Disorder

Phase 2 & 3
Recruiting
Research Sponsored by ACADIA Pharmaceuticals Inc.
Eligibility Criteria Checklist
Specific guidelines that determine who can or cannot participate in a clinical trial
Must have
Male or female and 5 through 17 years of age
For female patients only: unable to become pregnant or agree to use a highly effective non-hormonal method of contraception. Females of childbearing potential must have a negative pregnancy test
Must not have
Requires treatment with a medication prohibited by the protocol, including concomitant psychotropic drugs targeting irritability, including those used off-label (clonidine, guanfacine, and propranolol; lithium, valproate; stimulants, and non-stimulant medications), medications that prolong the QT interval, and strong cytochrome P450 (CYP) 3A4 enzyme (CYP3A4) inhibitors and inducers
Any known history of angioedema, serotonin or neuroleptic malignant syndromes, dystonic reaction, or tardive dyskinesia, due to an antipsychotic or psychotropic medication
Timeline
Screening 28 days
Treatment 6 weeks
Follow Up 1 weeks
Awards & highlights

Summary

This trial is testing pimavanserin, a medication that may help reduce irritability, agitation, and self-harm in young individuals with autism. The study focuses on those who struggle with these challenging behaviors. Pimavanserin works by balancing brain chemicals to improve mood and behavior.

Who is the study for?
This trial is for children and adolescents aged 5 to 17 with Autism Spectrum Disorder (ASD) who show irritability, agitation, or self-injurious behaviors. They must be able to swallow pills, have not used antipsychotic drugs before or had issues with them, and meet specific criteria for ASD diagnosis. Girls must use non-hormonal contraception if of childbearing age.
What is being tested?
The study tests the effectiveness and safety of Pimavanserin compared to a placebo over six weeks in managing irritability associated with ASD. Participants are randomly assigned to either the medication or placebo group in a double-blind manner so neither they nor the researchers know who's receiving which treatment.
What are the potential side effects?
Potential side effects of Pimavanserin may include changes in heart rhythm, upset stomach, mood alterations like anxiety or depression, weight changes, fatigue, and possibly allergic reactions. The exact side effects will be monitored throughout the trial.

Eligibility Criteria

Inclusion Criteria

You may be eligible if you check “Yes” for the criteria below
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I am between 5 and 17 years old.
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I am a woman who cannot get pregnant or will use effective birth control.
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My child is between 5 and 17 years old.

Exclusion Criteria

You may be eligible for the trial if you check “No” for criteria below:
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I am not taking any medication that is not allowed in the study, including certain drugs for mood, heart rhythm, or those affecting liver enzymes.
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I have had severe reactions to mental health medications in the past.
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I have a genetic disorder linked to autism, behavioral issues, or severe intellectual disability.
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I have been seizure-free and not taken epilepsy medication for over 6 months.
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I weigh less than 15 kg.

Timeline

Screening ~ 28 days
Treatment ~ 6 weeks
Follow Up ~1 weeks
This trial's timeline: 28 days for screening, 6 weeks for treatment, and 1 weeks for reporting.

Treatment Details

Study Objectives

Study objectives can provide a clearer picture of what you can expect from a treatment.
Primary study objectives
Change from Baseline at Week 6 in caregiver-rated Aberrant Behavior Checklist (ABC) Irritability subscale score
Secondary study objectives
Change from Baseline at Week 6 in Caregiver Strain Questionnaire (CGSQ) scores
Change from Baseline at Week 6 in Clinical Global Impression-Severity (CGI-S) of Irritability score
Change from Baseline at Week 6 in Repetitive Behavior Scale-Revised (RBS-R) scores
+6 more

Side effects data

From 2021 Phase 4 trial • 6 Patients • NCT04188392
33%
sleepiness
17%
weight gain
17%
diarrhea
17%
arthralgia
17%
headache
17%
skin irritation
17%
dry mouth
100%
80%
60%
40%
20%
0%
Study treatment Arm
Open-label Treatment

Trial Design

3Treatment groups
Experimental Treatment
Placebo Group
Group I: Pimavanserin low doseExperimental Treatment1 Intervention
Patients aged 5 to 12 years: 10 mg/day pimavanserin Patients aged 13 to 17 years: 20 mg/day pimavanserin Pimavanserin given once daily, as capsule of 10 or 20 mg dose strength, respectively, according to the patient's age
Group II: Pimavanserin high doseExperimental Treatment1 Intervention
Patients aged 5 to 12 years: 20 mg/day pimavanserin Patients aged 13 to 17 years: 34 mg/day pimavanserin Pimavanserin given once daily, as capsule of 20 or 34 mg dose strength, respectively, according to the patient's age
Group III: PlaceboPlacebo Group1 Intervention
Placebo given once daily, as one capsule matching in size and color the respective pimavanserin treatment
Treatment
First Studied
Drug Approval Stage
How many patients have taken this drug
Pimavanserin
2018
Completed Phase 4
~3010

Research Highlights

Information in this section is not a recommendation. We encourage patients to speak with their healthcare team when evaluating any treatment decision.
Mechanism Of Action
Side Effect Profile
Prior Approvals
Other Research
Common treatments for Autism Spectrum Disorder (ASD) often target neurotransmitter systems to alleviate symptoms such as irritability, agitation, and self-injurious behaviors. Pimavanserin, a selective serotonin inverse agonist and antagonist at 5-HT2A receptors, works by modulating serotonin activity, which is crucial for mood regulation and social behavior. This mechanism is particularly relevant for ASD patients as it can help manage behavioral symptoms without the side effects commonly associated with traditional antipsychotics. Other treatments may include SSRIs, which increase serotonin levels to improve mood and reduce anxiety, and atypical antipsychotics, which target multiple neurotransmitter receptors to address a range of symptoms. Understanding these mechanisms is essential for tailoring treatments to individual needs and improving overall quality of life for ASD patients.
Common Defects of Spine Dynamics and Circuit Function in Neurodevelopmental Disorders: A Systematic Review of Findings From <i>in Vivo</i> Optical Imaging of Mouse Models.

Find a Location

Logistics

Travel, including flights, are covered

Your expenses for travel tickets for this trial will be reimbursed.

Other reimbursement is provided

Other forms of reimbursement are provided for this trial.

Who is running the clinical trial?

ACADIA Pharmaceuticals Inc.Lead Sponsor
47 Previous Clinical Trials
11,368 Total Patients Enrolled
2 Trials studying Autism Spectrum Disorder
258 Patients Enrolled for Autism Spectrum Disorder

Media Library

Pimavanserin (Serotonin Inverse Agonist) Clinical Trial Eligibility Overview. Trial Name: NCT05523895 — Phase 2 & 3
Autism Spectrum Disorder Research Study Groups: Pimavanserin high dose, Placebo, Pimavanserin low dose
Autism Spectrum Disorder Clinical Trial 2023: Pimavanserin Highlights & Side Effects. Trial Name: NCT05523895 — Phase 2 & 3
Pimavanserin (Serotonin Inverse Agonist) 2023 Treatment Timeline for Medical Study. Trial Name: NCT05523895 — Phase 2 & 3
Autism Spectrum Disorder Patient Testimony for trial: Trial Name: NCT05523895 — Phase 2 & 3
~74 spots leftby Sep 2025