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Trial · Interventional

RecruitingPhase 3Registry data

An Open-label Study of NNZ-2591 in Pediatric Participants With Phelan-McDermid Syndrome

NCTNCT07593391 (opens ClinicalTrials.gov in a new tab)Other idNEU-2591-PMS-302
Open at ClinicalTrials.govAsk about this trial

Overview

Status
Recruiting
Phase
Phase 3
Enrollment
180 participants (estimated)
Sponsor
Neuren Pharmaceuticals Limited · Industry
Design
Allocation not applicable · Open label (no masking)
Countries
1 country

United States

Start
8 Jun 2026
Primary completion
29 Oct 2028 (estimated)
Completion
12 Nov 2028 (estimated)
First posted
18 May 2026
Last update posted
19 Oct 2026
Conditions
Phelan-McDermid Syndrome

Timeline

1 trial · 1 ongoing

  • Completed
  • Ongoing
  • Not yet recruiting
  • Stopped
  • Estimated dates (est.)
  • Results posted
2026202720282029
  1. Ph 3

    An Open-label Study of NNZ-2591 in Pediatric Participants With Phelan-McDermid Syndrome

    NCT07593391

    8 Jun 2026 to est. 12 Nov 2028

Registry summary

Text and fields below are the sponsor's entries at ClinicalTrials.gov, shown as posted.

This Phase 3, open-label extension, multicenter study will evaluate long-term safety, tolerability and efficacy of NNZ-2591 in pediatric participants with Phelan- McDermid Syndrome.

Interventions

  • NNZ-2591Drug

Arms1

  • Experimental

    NNZ-2591 Arm

    The total duration of this study for each participant will be up to up to 56 weeks.

Primary outcomes14

Outcomes the sponsor listed as primary.

  1. Long-term safety and tolerability of NNZ-2591 as assessed by the incidence of adverse events across participants

    Time frame · Baseline through Safety Follow-Up (Month 12)

    Registry description

    Incidence of TEAEs, AESI and SAEs across participants

  2. Long-term safety and tolerability of NNZ-2591 as assessed by changes from Baseline assessments of ECG parameters events across participants.

    Time frame · Baseline through Month 12

    Registry description

    Change from Baseline in ECG Heart Rate (bpm)

  3. Long-term safety and tolerability of NNZ-2591 as assessed by changes from Baseline assessments of ECG parameters events across participants.

    Time frame · Baseline through Safety Follow-Up (Month 12)

    Registry description

    Change from Baseline PR Interval (ms QRS interval (ms)

  4. Long-term safety and tolerability of NNZ-2591 as assessed by changes from Baseline assessments of ECG parameters events across participants.

    Time frame · Baseline through Safety Follow-Up (Month 12)

    Registry description

    Change from Baseline in QT interval (ms)

  5. Long-term safety and tolerability of NNZ-2591 as assessed by changes from Baseline assessments of ECG parameters events across participants.

    Time frame · Baseline through Safety Follow-Up (Month 12)

    Registry description

    Change from Baseline in QTcB interval (ms)

  6. Long-term safety and tolerability of NNZ-2591 as assessed by changes from Baseline assessments of ECG parameters events across participants.

    Time frame · Baseline through Safety Follow-Up (Month 12)

    Registry description

    Change from Baseline in QTcF interval (ms)

  7. Long-term safety and tolerability of NNZ-2591 as assessed by changes from Baseline assessments of ECG parameters events across participants.

    Time frame · Baseline through Safety Follow-Up (Month 12)

    Registry description

    Change from Baseline in RR interval (ms)

  8. Long-term safety and tolerability of NNZ-2591 as assessed by changes from Baseline assessments of vital sign parameters events across participants.

    Time frame · Baseline through Month 12

    Registry description

    Change from Baseline for heart rate (bpm)

  9. Long-term safety and tolerability of NNZ-2591 as assessed by changes from Baseline assessments of vital sign parameters events across participants.

    Time frame · Baseline through Month 12

    Registry description

    Change from Baseline for respiration rate (breaths per minute)

  10. Long-term safety and tolerability of NNZ-2591 as assessed by changes from Baseline assessments of vital sign parameters events across participants.

    Time frame · Baseline through Month 12

    Registry description

    Change from Baseline for Temperature (Celsius)

  11. Long-term safety and tolerability of NNZ-2591 as assessed by changes from Baseline assessments of vital sign parameters events across participants.

    Time frame · Baseline through Month 12

    Registry description

    Change from Baseline for Diastolic Blood Pressure (mm Hg)

  12. Long-term safety and tolerability of NNZ-2591 as assessed by changes from Baseline assessments of vital sign parameters events across participants.

    Time frame · Baseline through Month 12

    Registry description

    Change from Baseline for Systolic Blood Pressure (mm Hg)

  13. Long-term safety and tolerability of NNZ-2591 as incidence of abnormal, clinically significant clinical laboratory parameters events across participants.

    Time frame · Baseline through Month 12

    Registry description

    Incidence of abnormal and clinically significant laboratory parameters

  14. Long-term safety and tolerability of NNZ-2591 as incidence of abnormal, clinically significant physical examination findings across participants.

    Time frame · Baseline through Month 12

    Registry description

    Incidence of abnormal, clinically significant physical examination findings

Secondary outcomes(7)

  1. Efficacy of NNZ-2591 as measured by the Phelan-McDermid Syndrome Assessment of Change (PMSA-C) overall score

    Time frame · Months 3 and 12

    Registry description

    Efficacy of NNZ-2591 as measured by the Phelan-McDermid Syndrome Assessment of Change (PMSA-C) overall score. The PMSA-C scores range from 1 to 7 with 1 indicating very much improved and 7 indicating very much worse.

  2. Efficacy of NNZ-2591 as measured by the change from baseline in the Vineland Adaptive Behavior Scales-3, Interview version (Vineland-3) receptive communication subdomain raw score.

    Time frame · Months 3 and 12

    Registry description

    Efficacy of NNZ-2591 as measured by the change from baseline in the Vineland Adaptive Behavior Scales-3, Interview version (Vineland-3) receptive communication subdomain raw score. A higher raw score for the receptive communication subdomain indicates better adaptive behavior.

  3. Efficacy of NNZ-2591 as measured by the Phelan-McDermid Syndrome Assessment of Change (PMSA-C) domain scores.

    Time frame · Months 3 and 12

    Registry description

    Efficacy of NNZ-2591 as measured by the Phelan-McDermid Syndrome Assessment of Change (PMSA-C) domain scores. The PMSA-C domain scores range from 1 to 7 with 1 indicating very much improved and 7 indicating very much worse.

  4. Efficacy of NNZ-2591 as measured by the Caregiver Impression of Change (CIC) domain scores.

    Time frame · Months 3 and 12

    Registry description

    Efficacy of NNZ-2591 as measured by the Caregiver Impression of Change (CIC) domain scores. The CIC scores range from 1 to 7 with 1 indicating very much improved and 7 indicating very much worse.

  5. Efficacy of NNZ-2591 as measured by the change from baseline in Phelan-McDermid Syndrome Assessment of Severity (PMSA-S) domain scores.

    Time frame · Months 3 and 12

    Registry description

    Efficacy of NNZ-2591 as measured by the change from baseline in Phelan-McDermid Syndrome Assessment of Severity (PMSA-S) domain scores. The PMSA-S scores range from 1 to 7 with 1 indicating typical for age, not at all impaired and 7 among the most severely impaired.

  6. Efficacy of NNZ-2591 as measured by the change from baseline in Phelan-McDermid Syndrome Assessment of Severity (PMSA-S) overall score.

    Time frame · Months 3 and 12

    Registry description

    Efficacy of NNZ-2591 as measured by the change from baseline in Phelan-McDermid Syndrome Assessment of Severity (PMSA-S) overall score. The PMSA-S scores range from 1 to 7 with 1 indicating typical for age, not at all impaired and 7 among the most severely impaired.

  7. Efficacy of NNZ-2591 as measured by the change from baseline in PMS Clinician Domain Specific Rating Scale (PMS-DSRS) scores.

    Time frame · Months 3 and 12

    Registry description

    Efficacy of NNZ-2591 as measured by the change from baseline in PMS Clinician Domain Specific Rating Scale (PMS-DSRS) scores. The PMS-DSRS scores range from 0 to 4 with 0 indicating Symptom Not Present and 4 indicating Very Severe.

Posted results

Values are shown as posted at ClinicalTrials.gov, with their units. PepBank has not converted, pooled or compared them.

No results are posted for this trial.

A trial that is still running, or that stopped early, may post results later.

Registry data comes from ClinicalTrials.gov. Study results come from studies, not from the registry. How PepBank works

Studies0

Studies that cite this trial.

No study cites this trial.

Eligibility

Who could join, as posted.

Sex
All
Age
from 3 Years up to 12 Years
Healthy volunteers
Not accepted
Inclusion and exclusion criteria, as posted
Inclusion Criteria: 1. Male or female pediatric participants with Phelan-McDermid syndrome ages 3 to 12 years (inclusive) at the time of signing the informed consent for the antecedent study. 2. Participant must have completed all applicable study visits for the antecedent study in which they participated. 3. Body weight ≥ 10 kg at Screening/Baseline. 4. Participants with a PMSA-S overall score ≥ 3 at the Screening and Baseline visits. 5. Not actively undergoing regression or loss of skills. Exclusion Criteria: 1. Use of exclusionary medication or unstable treatment regimens of acceptable concomitant medications as required by the protocol. 2. Participants with seizures must be controlled on no more than 2 anticonvulsant medications (not counting rescue medications). 3. Psychotropic medications or any other medication used for a chronic illness (not including antibiotics, pain relievers, anti-diarrheals, and laxatives) with doses and dosing regimen that have not been stable for at least 4 weeks before Screening. If the treatment was discontinued, the discontinuation must have occurred no fewer than 2 weeks before the start of Screening. 4. Any intercurrent seizures in the past 6 months and /or more than 1 seizure in the past 12 months. •A single febrile seizure in the 6 months prior to screening is allowable if no rescue medication was required. 5. Abnormal liver function laboratory results during the Screening period, as defined by the protocol 6. Abnormal QT interval on Screening ECG as defined by the protocol.

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