Trial results
AI generated results summary. Written by an AI model from the official source data and checked on a sample basis. It can contain mistakes, so confirm anything important against the original source. How we use AI
According to the results reported on ClinicalTrials.gov, this trial (NCT05523895) enrolled 237 people across three groups to look at the effects of two different doses of a medicine called pimavanserin compared to a placebo (a dummy treatment with no active ingredient) in people with challenging behaviours, specifically irritability. The groups were: 78 people received placebo, 78 received a lower dose of pimavanserin, and 81 received a higher dose. By the end of the study, 74, 67, and 75 people in each group respectively had completed the trial. The primary thing being measured was a change in irritability scores on a caregiver-rated questionnaire called the Aberrant Behavior Checklist Irritability (ABC-I) subscale. This is a scale where caregivers rate 15 behaviour-related items, with a total score ranging from 0 (no problems) to 45 (severe problems) — a lower score means less irritability. The reported data shows that after six weeks, the average score change from the starting point was minus 9.6 points in the placebo group, minus 11.2 points in the low-dose pimavanserin group, and minus 11.2 points in the high-dose pimavanserin group. In other words, all three groups showed a reported reduction in irritability scores over the course of the trial. No secondary outcome measure data was reported in the structured results provided. These are the results as reported to ClinicalTrials.gov. They are not medical advice — always discuss what they mean for you with your doctor.
View full results on ClinicalTrials.gov ↗ · Read the linked publication on PubMed (PMID 42162607) ↗
These are the results as reported to ClinicalTrials.gov, not medical advice. Verify independently with the trial site and discuss what they mean for you with your doctor.
Phase 3 Autism Spectrum Disorder Trial, Completed
Who may be able to join
AI generated eligibility summary. Written by an AI model from the official source data and checked on a sample basis. It can contain mistakes, so confirm anything important against the original source. How we use AI
Who might be able to join this trial:
- You are between 5 and 17 years old (male or female)
- You, your parent or legal guardian, and any designated caregiver understand the study and are willing to follow its requirements
- You are able to swallow a small capsule without difficulty
- You have been diagnosed with Autism Spectrum Disorder (ASD) according to standard diagnostic guidelines, confirmed by a specific diagnostic interview
- Your irritability symptoms score at a certain level or above on two standard rating scales used by clinicians
- You do not have any other mental health condition at the same time, except for ADHD or an anxiety disorder
- You have either never taken antipsychotic medication, taken it for less than 2 weeks, or previously had problems tolerating it
- If you are currently receiving behavioural therapy for autism, that therapy has been the same for at least 4 weeks and will stay the same during the study
- For female patients only: you are unable to become pregnant, OR you agree to use a reliable non-hormonal form of contraception, AND you have a negative pregnancy test
Who may not be able to join:
- You currently take certain medications that are not allowed in this study, including some drugs used for irritability, mood stabilisers, certain heart medications, or certain drugs that affect how the body processes medicines (confirm with trial site)
- You have changed any of your regular medications or their doses in the last 4 weeks
- You have a known history of certain serious reactions to antipsychotic or psychiatric medications, such as dangerous muscle reactions or movement disorders (confirm with trial site)
- You are considered to be at significant risk of suicide, or of harming yourself or others
- You are considered to pose a safety risk to other patients, caregivers, or others due to potential for serious aggressive behaviour
- You have a positive result on a urine drug test
- You have had a substance use disorder within the last 6 months
- You have a confirmed genetic condition linked to ASD, or a very significant intellectual disability
- You have a history of seizures, unless you have been seizure-free and off epilepsy medication for at least 6 months
- You have any condition the study doctor believes would interfere with your ability to take part safely or affect the study results
- You have had a serious or unstable medical or psychiatric condition in the last 12 weeks, including conditions affecting the heart, lungs, liver, kidneys, or nervous system, or a history of cancer
- You weigh less than 15 kg (about 33 lbs)
- You have a history of, or signs of, certain heart rhythm or electrical problems on a heart tracing (ECG)
- You or a family member has a known history of a heart condition called Long QT syndrome, or other related heart rhythm problems
- Someone in your household has had COVID-19 or tested positive for it in the last 4 weeks
- Certain blood or lab test results fall outside the ranges allowed by the study
- You are currently breastfeeding or have a positive pregnancy test
- You are known to be sensitive or allergic to the study drug (pimavanserin) or any of its ingredients
- You are currently taking part in another clinical research study
- You have taken part in more than 2 drug-based clinical research studies in the last 6 months
Important: Always verify eligibility with the trial site directly before applying.
Based on publicly available eligibility criteria from ClinicalTrials.gov. Verify directly with the trial site before acting. This is not medical advice.
Contact this trial
Australian sites
Contact details sourced from ClinicalTrials.gov. Verify directly with the trial site before attending.
GP referral letter
Print a one-page summary to share with your doctor.
Trial details
Where this trial is recruiting
3 site(s) in Australia. Confirm current status and contact details directly with the trial site.
Primary endpoints
Change From Baseline at Week 6 in Caregiver-rated Aberrant Behavior Checklist Irritability (ABC-I) Subscale Score
Can't join this trial?
Data last synced from ClinicalTrials.gov: 28 July 2026. Trial status can change. Always verify current status directly with the trial site before making any decision.