NNZ-2591 improves sleep in children and adolescents with Phelan-McDermid syndrome
In an open-label phase 2 trial, NNZ-2591 was associated with significant improvements in sleep assessments among 18 children and adolescents with Phelan-McDermid syndrome after 13 weeks of treatment. Sleep was one of 14 secondary efficacy endpoints, with significant improvement from baseline observed at week 13.
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NNZ-2591 improves sleep in children and adolescents with Phelan-McDermid syndrome The current body of evidence comprises 1 study. EvidenceHub rates the overall confidence at 38/100 (low).
The Claim
NNZ-2591 improves sleep in children and adolescents with Phelan-McDermid syndrome
This conclusion is most relevant to: Children and adolescents aged 3-12 years with Phelan-McDermid syndrome (mean age 8.6 years, mean weight 30.4 kg).
What the Research Shows
The conclusion draws on 1 linked study. Highlights from the cited literature:
- ▸NNZ-2591 in Children and Adolescents With Phelan-McDermid Syndrome: Single-Group, Open-Label, Phase 2 Trial Results. (Neurology. Genetics, 2025) —
How It Works
The proposed biological pathway:
- ▸NNZ-2591 is a synthetic analog of cyclic glycine-proline, a metabolite of insulin-like growth factor 1
- ▸It modulates neurotrophic signaling pathways relevant to neurodevelopment
- ▸Improves synaptic function and neural connectivity in PMS
- ▸Result: Clinically meaningful improvements in sleep and other PMS symptoms
Who Might Benefit
Evidence fit by population:
- ▸Children and adolescents aged 3-12 years with Phelan-McDermid syndrome (mean age 8.6 years, mean weight 30.4 kg)
Recommended Dose
12 mg/kg twice daily (target dose after uptitration)
Limitations & Caveats
Important context when interpreting this evidence:
- ▸Open-label design with no placebo control, limiting causal inference
- ▸Small sample size (n=18) reduces generalizability and statistical power
- ▸Sleep was a secondary endpoint and not assessed with validated sleep-specific instruments
Frequently Asked Questions
What is NNZ-2591?▼
NNZ-2591 is a synthetic analog of cyclic glycine-proline, a metabolite of insulin-like growth factor 1, being tested for Phelan-McDermid syndrome.
Did NNZ-2591 improve sleep in this study?▼
Yes, sleep assessments showed significant improvement from baseline at week 13 in children and adolescents with PMS.
What were the main side effects of NNZ-2591?▼
NNZ-2591 was well tolerated; most treatment-emergent adverse events were mild to moderate.
Is NNZ-2591 approved for PMS?▼
No, this is a phase 2 trial; the drug is not yet approved. Further evaluation is ongoing.
References
- 1.Neumeyer AM, Srivastava S, Holder JL, Milad MA, Squires L, Jones NE, Glass L, Berry-Kravis E. “NNZ-2591 in Children and Adolescents With Phelan-McDermid Syndrome: Single-Group, Open-Label, Phase 2 Trial Results..” Neurology. Genetics, 2025. PMID: 41450730 DOI: 10.1212/NXG.0000000000200338