Trial · NCT05555615
Extension Study of Pimavanserin in Irritability Associated With Autism Spectrum Disorder
NCT05555615, Phase 2, Phase 3, Terminated, ACADIA Pharmaceuticals Inc.; results first posted 2025-12-03
3 sourcestrials-2026-11-12-0.5.0
Cite this record
ConductScience Library. Extension Study of Pimavanserin in Irritability Associated With Autism Spectrum Disorder. Trials, record NCT05555615. Release trials-2026-11-12-0.5.0, 12 Nov 2026. https://conductscience.org/library/trials/NCT05555615
On this page
Trial
As registered on ClinicalTrials.gov, in the graph's capture of the registry.
- Title
- Extension Study of Pimavanserin in Irritability Associated With Autism Spectrum Disorder
- NCT number
- NCT05555615
- Status
- Terminated
- Phases
- Phase 2, Phase 3
- Enrollment
- 209 participants, actual
- Lead sponsor
- ACADIA Pharmaceuticals Inc.
- Conditions
- Irritability Associated With Autism Spectrum Disorder
- Interventions
- Pimavanserin
- First posted
- 2022-09-27
- Last updated
- 2025-12-03
- Results first posted
- 2025-12-03
- Limitations and caveats
- The study was terminated early by the Sponsor due to lack of efficacy in the antecedent double-blind study (ACP-103-069).
Source ClinicalTrials.gov
Registered outcomes2
Each outcome the trial registered, primary first, in ClinicalTrials.gov's words.
| List | Outcome | Time frame | Description |
|---|---|---|---|
| Primary | Treatment-emergent Adverse Events | 52 weeks | Number (%) of patients with treatment emergent adverse events |
| Secondary | Aberrant Behavior Checklist-Irritability (ABC-I) and Clinical Global Impression-Improvement (CGI-I) Response Rate | 52 weeks | The response rate was defined as the proportion of patients with at least 25% reduction from baseline to Week 52 in ABC-I and a CGI-I of irritability score of 1 (very much improved) or 2 (much improved) at Week 52, compared to baseline. Baseline was the baseline of the antecedent double-blind study APC-103-069. The ABC is a parent/caregiver-rated scale comprised of 5 subscales encompassing 58 items. Subscales are irritability, lethargy, stereotypic behavior, hyperactivity, and inappropriate speech. Items are rated on a 4-point Likert scale ranging from 0 (not at all a problem) to 3 (the problem is severe), with higher scores indicating more severe problems. Subscale scores are calculated by summing the items within that subscale. The CGI-I is a clinician-rated, 7-point scale to assess how much the patient's illness (here: the patient's irritability) has changed relative to baseline. Scores range from 1 (very much improved) to 7 (very much worse). |
Source ClinicalTrials.gov
Outcomes2
Each outcome the trial posted results for, in ClinicalTrials.gov's words.
| Type | Outcome | Time frame | Population | Units | Measured as |
|---|---|---|---|---|---|
| PRIMARY | Treatment-emergent Adverse Events | 52 weeks | All patients enrolled and treated | Participants | COUNT_OF_PARTICIPANTS |
| SECONDARY | Aberrant Behavior Checklist-Irritability (ABC-I) and Clinical Global Impression-Improvement (CGI-I) Response Rate | 52 weeks | All patients enrolled and treated | Participants | COUNT_OF_PARTICIPANTS |
Source ClinicalTrials.gov
Results by group2
Each measurement the trial posted, group by group, in the words and numbers it posted.
| Outcome | Group | Category | Value | Spread | Units |
|---|---|---|---|---|---|
| Treatment-emergent Adverse Events | Pimavanserin | 132 | Participants | ||
| Aberrant Behavior Checklist-Irritability (ABC-I) and Clinical Global Impression-Improvement (CGI-I) Response Rate | Pimavanserin | 51 | Participants |
Source ClinicalTrials.gov
Participant flow3
How many started, completed or left each group, period by period.
| Period | Milestone | Group | Participants | Units counted |
|---|---|---|---|---|
| Overall Study | STARTED | Pimavanserin | 209 | |
| Overall Study | COMPLETED | Pimavanserin | 67 | |
| Overall Study | NOT COMPLETED | Pimavanserin | 142 |
Source ClinicalTrials.gov
Adverse events10
Each adverse event the trial posted, group by group: the participants affected out of those at risk.
| Type | Event | Organ system | Group | Affected | At risk | Events |
|---|---|---|---|---|---|---|
| other | Vomiting | Gastrointestinal disorders | Pimavanserin | 15 | 209 | 17 |
| other | Pyrexia | General disorders | Pimavanserin | 11 | 209 | 12 |
| other | Upper respiratory tract infection | Infections and infestations | Pimavanserin | 21 | 209 | 29 |
| other | Nasopharyngitis | Infections and infestations | Pimavanserin | 13 | 209 | 19 |
| other | Headache | Nervous system disorders | Pimavanserin | 14 | 209 | 16 |
| serious | Drug hypersensitivity | Immune system disorders | Pimavanserin | 1 | 209 | 1 |
| serious | Pneumonia respiratory syncytial viral | Infections and infestations | Pimavanserin | 1 | 209 | 1 |
| serious | Heart rate irregular | Investigations | Pimavanserin | 1 | 209 | 1 |
| serious | Febrile convulsion | Nervous system disorders | Pimavanserin | 1 | 209 | 1 |
| serious | Aggression | Psychiatric disorders | Pimavanserin | 1 | 209 | 1 |
Source ClinicalTrials.gov
Adverse event totals3
The totals the trial posted for each group.
| Total | Group | Affected | At risk |
|---|---|---|---|
| Total, all-cause mortality | Pimavanserin | 0 | 209 |
| Total, other adverse events | Pimavanserin | 66 | 209 |
| Total, serious adverse events | Pimavanserin | 5 | 209 |
Source ClinicalTrials.gov
Papers0
The papers the trial lists on ClinicalTrials.gov.
None in this release.
Grants0
The grants NIH RePORTER links to the trial, newest funded first: NIH's, and some of AHRQ's, CDC's, FDA's and VA's. Each shows its title, principal investigators, organization and funder in its newest year.
None in this release.
Trial comparisons0
Comparisons of the trial's two groups, calculated by ConductScience from the counts it posted.
None in this release.
Tests0
The ConductCognition tests this trial's registered outcomes name, as ScienceGraph matched them in trial-tests-2026-11-12-0.2.1.
None in this release.
Data dates
The day each source was copied for this release.
Sources 3
- ClinicalTrials.gov's posted results, through CTTI's AACTFreely available. Acknowledgement requested
- ClinicalTrials.govNo license stated
- NIH RePORTER's clinical studies and project filesPublic domain
Each source's terms
- ClinicalTrials.gov's posted results, through CTTI's AACTClinicalTrials.gov data via Aggregate Analysis of ClinicalTrials.gov (AACT), CTTI. CTTI makes its materials freely available and requests acknowledgement. https://aact.ctti-clinicaltrials.org/documentation/299
- ClinicalTrials.govnone stated
- NIH RePORTER's clinical studies and project filesPublic domain (NIH RePORTER)
ClinicalTrials.gov's data carry an international copyright outside the United States: https://clinicaltrials.gov/about-site/terms-conditions.
For software
Read this trial from software.
The record and each of its lists are JSON, twenty rows a page. No key.
GET https://conductscience.org/api/trials/v1/NCT05555615
GET https://conductscience.org/api/trials/v1/NCT05555615/registered