NCT07593391 · Neuren Pharmaceuticals Limited
An Open-label Study of NNZ-2591 in Pediatric Participants With Phelan-McDermid Syndrome
What this study is about
This Phase 3, where both patients and doctors know the treatment given extension, conducted at multiple hospitals study will evaluate long-term safety, tolerability and effectiveness of NNZ-2591 in pediatric participants with Phelan- McDermid Syndrome.
View original scientific description
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.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- 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.
- Participant must have completed all applicable study visits for the antecedent study in which they participated.
- Body weight ≥ 10 kg at Screening/Baseline.
- Participants with a PMSA-S overall score ≥ 3 at the Screening and Baseline visits.
- Not actively undergoing regression or loss of skills.
Exclusion criteria
- Use of exclusionary medication or unstable treatment regimens of acceptable concomitant medications as required by the protocol.
- Participants with seizures must be controlled on no more than 2 anticonvulsant medications (not counting rescue medications).
- 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.
- 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.
- Abnormal liver function laboratory results during the Screening period, as defined by the protocol
- Abnormal QT interval on Screening ECG as defined by the protocol.
Where
- San Rafael, California
- Chevy Chase, Maryland
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced May 22, 2026 · Source of record for eligibility and locations