Trial Outcomes & Findings for Extension Study of Pimavanserin in Irritability Associated With Autism Spectrum Disorder (NCT NCT05555615)
NCT ID: NCT05555615
Last Updated: 2025-12-03
Results Overview
Number (%) of patients with treatment emergent adverse events
Recruitment status
TERMINATED
Study phase
PHASE2/PHASE3
Target enrollment
209 participants
Primary outcome timeframe
52 weeks
Results posted on
2025-12-03
Participant Flow
This was an open-label extension study of the antecedent double-blind study ACP-103-069. Patients were eligible for this study if they had completed the treatment period of study ACP-103-069.
Participant milestones
| Measure |
Pimavanserin
Pimavanserin once daily administered using age-based dosing:
* pimavanserin low dose during Weeks 1 and 2 (age 5 to 12 years: 10 mg/day; age 13 to 17 years: 20 mg/day)
* pimavanserin high dose from Week 3 onwards (5 to 12 years: 20 mg/day; 13 to 17 years: 34 mg/day) based on the investigator's assessment of clinical response Dose adjustments were allowed after Week 2 and up to Week 20, based on the investigator's assessment of clinical response and tolerability.
|
|---|---|
|
Overall Study
STARTED
|
209
|
|
Overall Study
COMPLETED
|
67
|
|
Overall Study
NOT COMPLETED
|
142
|
Reasons for withdrawal
| Measure |
Pimavanserin
Pimavanserin once daily administered using age-based dosing:
* pimavanserin low dose during Weeks 1 and 2 (age 5 to 12 years: 10 mg/day; age 13 to 17 years: 20 mg/day)
* pimavanserin high dose from Week 3 onwards (5 to 12 years: 20 mg/day; 13 to 17 years: 34 mg/day) based on the investigator's assessment of clinical response Dose adjustments were allowed after Week 2 and up to Week 20, based on the investigator's assessment of clinical response and tolerability.
|
|---|---|
|
Overall Study
Adverse Event
|
7
|
|
Overall Study
Lack of Efficacy
|
12
|
|
Overall Study
Lost to Follow-up
|
10
|
|
Overall Study
Noncompliance with study drug
|
5
|
|
Overall Study
Physician Decision
|
2
|
|
Overall Study
Study terminated by sponsor
|
80
|
|
Overall Study
Prohibited medication use
|
2
|
|
Overall Study
Withdrawal by Subject
|
20
|
|
Overall Study
Not further specified
|
4
|
Baseline Characteristics
Extension Study of Pimavanserin in Irritability Associated With Autism Spectrum Disorder
Baseline characteristics by cohort
| Measure |
Pimavanserin
n=209 Participants
Pimavanserin once daily administered using age-based dosing:
* pimavanserin low dose during Weeks 1 and 2 (age 5 to 12 years: 10 mg/day; age 13 to 17 years: 20 mg/day)
* pimavanserin high dose from Week 3 onwards (5 to 12 years: 20 mg/day; 13 to 17 years: 34 mg/day) based on the investigator's assessment of clinical response Dose adjustments were allowed after Week 2 and up to Week 20, based on the investigator's assessment of clinical response and tolerability.
|
|---|---|
|
Age, Continuous
|
10.1 years
STANDARD_DEVIATION 3.16 • n=9 Participants
|
|
Sex: Female, Male
Female
|
46 Participants
n=9 Participants
|
|
Sex: Female, Male
Male
|
163 Participants
n=9 Participants
|
|
Race (NIH/OMB)
American Indian or Alaska Native
|
1 Participants
n=9 Participants
|
|
Race (NIH/OMB)
Asian
|
9 Participants
n=9 Participants
|
|
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
|
1 Participants
n=9 Participants
|
|
Race (NIH/OMB)
Black or African American
|
24 Participants
n=9 Participants
|
|
Race (NIH/OMB)
White
|
158 Participants
n=9 Participants
|
|
Race (NIH/OMB)
More than one race
|
0 Participants
n=9 Participants
|
|
Race (NIH/OMB)
Unknown or Not Reported
|
16 Participants
n=9 Participants
|
|
Region of Enrollment
Hungary
|
17 participants
n=9 Participants
|
|
Region of Enrollment
United States
|
98 participants
n=9 Participants
|
|
Region of Enrollment
Poland
|
55 participants
n=9 Participants
|
|
Region of Enrollment
Italy
|
9 participants
n=9 Participants
|
|
Region of Enrollment
France
|
11 participants
n=9 Participants
|
|
Region of Enrollment
Serbia
|
9 participants
n=9 Participants
|
|
Region of Enrollment
Australia
|
6 participants
n=9 Participants
|
|
Region of Enrollment
Spain
|
4 participants
n=9 Participants
|
PRIMARY outcome
Timeframe: 52 weeksPopulation: All patients enrolled and treated
Number (%) of patients with treatment emergent adverse events
Outcome measures
| Measure |
Pimavanserin
n=209 Participants
Pimavanserin once daily. All patients will receive the pimavanserin low dose (patients aged 5 to 12 years: 10 mg/day pimavanserin; patients aged 13 to 17 years: 20 mg/day) the first 2 weeks of the study. Thereafter, the dose may be increased to the high dose (5 to 12 years: 20 mg/day; 13 to 17 years: 34 mg/day) based on the Investigator's assessment of clinical response.
After Week 2 and up to Week 20, dose adjustments are allowed at any clinic visit based on the Investigator's assessment of clinical response and tolerability. No further dose adjustments are allowed after Week 20.
Pimavanserin: Pimavanserin given once daily, as capsule of 10, 20, or 34 mg dose strength, respectively, according to the patient's age
|
|---|---|
|
Treatment-emergent Adverse Events
|
132 Participants
|
SECONDARY outcome
Timeframe: 52 weeksPopulation: All patients enrolled and treated
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).
Outcome measures
| Measure |
Pimavanserin
n=209 Participants
Pimavanserin once daily. All patients will receive the pimavanserin low dose (patients aged 5 to 12 years: 10 mg/day pimavanserin; patients aged 13 to 17 years: 20 mg/day) the first 2 weeks of the study. Thereafter, the dose may be increased to the high dose (5 to 12 years: 20 mg/day; 13 to 17 years: 34 mg/day) based on the Investigator's assessment of clinical response.
After Week 2 and up to Week 20, dose adjustments are allowed at any clinic visit based on the Investigator's assessment of clinical response and tolerability. No further dose adjustments are allowed after Week 20.
Pimavanserin: Pimavanserin given once daily, as capsule of 10, 20, or 34 mg dose strength, respectively, according to the patient's age
|
|---|---|
|
Aberrant Behavior Checklist-Irritability (ABC-I) and Clinical Global Impression-Improvement (CGI-I) Response Rate
|
51 Participants
|
Adverse Events
Pimavanserin
Serious events: 5 serious events
Other events: 66 other events
Deaths: 0 deaths
Serious adverse events
| Measure |
Pimavanserin
n=209 participants at risk
Pimavanserin once daily administered using age-based dosing:
* pimavanserin low dose during Weeks 1 and 2 (age 5 to 12 years: 10 mg/day; age 13 to 17 years: 20 mg/day)
* pimavanserin high dose from Week 3 onwards (5 to 12 years: 20 mg/day; 13 to 17 years: 34 mg/day) based on the investigator's assessment of clinical response Dose adjustments were allowed after Week 2 and up to Week 20, based on the investigator's assessment of clinical response and tolerability.
|
|---|---|
|
Immune system disorders
Drug hypersensitivity
|
0.48%
1/209 • Number of events 1 • 52 weeks (study terminated early by the sponsor)
|
|
Infections and infestations
Pneumonia respiratory syncytial viral
|
0.48%
1/209 • Number of events 1 • 52 weeks (study terminated early by the sponsor)
|
|
Investigations
Heart rate irregular
|
0.48%
1/209 • Number of events 1 • 52 weeks (study terminated early by the sponsor)
|
|
Nervous system disorders
Febrile convulsion
|
0.48%
1/209 • Number of events 1 • 52 weeks (study terminated early by the sponsor)
|
|
Psychiatric disorders
Aggression
|
0.48%
1/209 • Number of events 1 • 52 weeks (study terminated early by the sponsor)
|
Other adverse events
| Measure |
Pimavanserin
n=209 participants at risk
Pimavanserin once daily administered using age-based dosing:
* pimavanserin low dose during Weeks 1 and 2 (age 5 to 12 years: 10 mg/day; age 13 to 17 years: 20 mg/day)
* pimavanserin high dose from Week 3 onwards (5 to 12 years: 20 mg/day; 13 to 17 years: 34 mg/day) based on the investigator's assessment of clinical response Dose adjustments were allowed after Week 2 and up to Week 20, based on the investigator's assessment of clinical response and tolerability.
|
|---|---|
|
Gastrointestinal disorders
Vomiting
|
7.2%
15/209 • Number of events 17 • 52 weeks (study terminated early by the sponsor)
|
|
General disorders
Pyrexia
|
5.3%
11/209 • Number of events 12 • 52 weeks (study terminated early by the sponsor)
|
|
Infections and infestations
Upper respiratory tract infection
|
10.0%
21/209 • Number of events 29 • 52 weeks (study terminated early by the sponsor)
|
|
Infections and infestations
Nasopharyngitis
|
6.2%
13/209 • Number of events 19 • 52 weeks (study terminated early by the sponsor)
|
|
Nervous system disorders
Headache
|
6.7%
14/209 • Number of events 16 • 52 weeks (study terminated early by the sponsor)
|
Additional Information
Sr. Dir. Medical Information and Medical Communications
Acadia Pharmaceuticals Inc.
Phone: 844-422-2342
Email: [email protected]
Results disclosure agreements
- Principal investigator is a sponsor employee Investigator may publish the study results, relative to their own patients, only after review, comment and approval by the sponsor. No publication of confidential information shall be made without the sponsor's prior written consent. At least 60 days prior to submitting a manuscript or prior to any public presentation, a copy of the manuscript or presentation will be provided to the Sponsor for review and comment. The sponsor has 60 days to review and comment.
- Publication restrictions are in place
Restriction type: OTHER