Is NNZ-2591 safe?

Q: Is NNZ-2591 safe?

13-week trial; no safety withdrawals; short In the 13-week trial, adverse events that appeared during treatment were mostly mild or moderate. No one died or stopped treatment for safety reasons. That is reassuring but limited. A study of 18 children over three months cannot reveal uncommon side effects. It cannot show anything about long-term use. There are no data in adults. There are none on effects outside the trial groups.

13-week trial; no safety withdrawals; short

CAnimal and cell studiesIn clinical trialsas of 2026-10-27

In the 13-week trial, adverse events that appeared during treatment were mostly mild or moderate. No one died or stopped treatment for safety reasons. That is reassuring but limited. A study of 18 children over three months cannot reveal uncommon side effects. It cannot show anything about long-term use. There are no data in adults. There are none on effects outside the trial groups. ¹

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Citations

Neumeyer 2025 (published online December 2025; Feb 2026 issue), Neurology Genetics: NNZ-2591 in children and adolescents with Phelan-McDermid syndrome, single-group open-label phase 2 trial doi.org
ClinicalTrials.gov NCT05025241: an open-label study of oral NNZ-2591 in Phelan-McDermid syndrome (PMS-001) clinicaltrials.gov
BioWorld 2024: Neuren's NNZ-2591 meets phase 2 endpoints in Pitt Hopkins syndrome (company report) bioworld.com
ClinicalTrials.gov: NCT07281079, phase 3 trial of NNZ-2591 in Phelan-McDermid syndrome clinicaltrials.gov

Reference information only, not medical advice. Drawn from the NNZ-2591 article, fact-checked against the cited sources. No dosing anywhere on this site.

Is NNZ-2591 safe?

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