STUDY MEDICATION

What is NNZ-2591?

NNZ-2591 is a synthetic version of a substance that occurs naturally in our brains, and has been designed to improve communication between nerve cells and reduce inflammation in the brain. The hope is that NNZ-2591 may improve communication between nerve cells, which could help with symptoms of Phelan McDermid Syndrome. 

NNZ-2591 is provided as a liquid to be taken by mouth, twice each day. 

Why are we studying NNZ-2591 in Phelan-McDermid Syndrome?

The goal of using NNZ-2591 is to normalize brain cell structure and signaling to improve the various symptoms observed in individuals with Phelan-McDermid syndrome. Brain levels of IGF-1 are low in people with Phelan-McDermid syndrome. NNZ-2591 mimics the actions of a naturally occurring peptide to help regulate the available amount of IGF-1 in the brain, reduce neuroinflammation, and ultimately improve brain cell structure and signaling.

In a mouse model with characteristics similar to those in Phelan-McDermid syndrome, treatment with NNZ-2591 normalized IGF-1 levels and corrected all observable deficits, including the elimination of seizures, while having no effect on healthy mice.

What are the possible side effects of NNZ-2591?

NNZ-2591 has been studied in a phase 1 trial of healthy adult volunteers and a phase 2 trial of children and adolescents with
Phelan-McDermid syndrome. 

In adults dosed who received NNZ-2591 for a duration of up to 7 days, the following side effects considered related to NNZ-2591
were seen:

  • Constipation
  • Drowsiness/fatigue
  • Diarrhea
  • Fever
  • Nausea
  • Vomiting
  • Aggressive behavior
  • Insomnia/trouble sleeping
  • Decreased appetite
  • Restlessness/hyperactivity
  • Blurred vision or difficulty focusing
  • Impaired balance
  • Dizziness
  • Mild irritation or discomfort caused from the drawing of blood or placement of electrocardiogram leads

In a phase 2 trial of children and adolescents with Phelan-McDermid syndrome who received NNZ-2591 for 13 weeks, the most common side effects (observed in 2–4 participants) were: 

  • Psychomotor hyperactivity
  • COVID-19
  • Drowsiness
  • Fever
  • Decreased appetite
  • Constipation
  • Diarrhea
  • Nausea
  • Vomiting
  • Common cold
  • Runny nose
  • Ear infection
  • Fatigue
  • Aggression
  • Insomnia/trouble sleeping

Tell your study doctor if your child experiences any side effects. This is important for assessing the safety of the study medication.