Neuren’s Tofinetide Successful in Phase 2 Clinical Trial in Fragile X

neuren Fragile X trial result graph

One of the outcome measures – the new Fragile X Syndrome Rating Scale – showing positive results. Blue: placebo; Yellow: low-dose trofinetide; Green: high-dose trofinetide

We are pleased to share great news adapted from Neuren’s press release:

Neuren’s phase 2 trial has successfully established proof of concept and provides a strong rationale for Neuren to move forward with developing trofinetide for Fragile X syndrome. In this initial small trial with a relatively short treatment period, trofinetide was very well tolerated, with the high dose (70 mg/kg twice daily) demonstrating a consistent pattern of clinical improvement, observed in both clinician and caregiver assessments.

After only 28 days of treatment, improvements were seen across core symptoms of Fragile X syndrome, including higher sensory tolerance, reduced anxiety, better self-regulation and more social engagement. No serious adverse events were reported.

Positive Results in Fragile X Syndrome and Rett Syndrome

Beneficial effects of trofinetide have now been observed in both Fragile X syndrome and Rett syndrome. Neuren announced encouraging results of their phase 2 trofinetide trial in Rett Syndrome last year.

Trofinetide Tested at FRAXA’s Drug Validation Initiative

FRAXA’s Drug Validation Initiative, run by Dr. Patricia Cogram in Santiago, Chile, enabled Neuren to quickly and efficiently test their molecule in Fragile X knockout mice. In fact, preliminary results in the Fragile X mice were even more promising then they were in Rett Syndrome, which was the original target for this drug, and those results launched Neuren’s Fragile X program.

See NNZ-2566, a novel analog of (1-3) IGF-1, as a potential therapeutic agent for Fragile X syndrome and

“Neuren is immensely grateful for the contribution that the Fragile X community has made to support our research endeavor. This type of clinical trial research is only possible because of the people with Fragile X and their families who devote their time and energy to participate in the study and the dedicated and knowledgeable clinicians who implement it. Moreover, FRAXA has been instrumental to this clinical trial both in providing practical support with outreach and enrollment, but also in providing insight on ways to better ensure outcomes are meaningful for families.”

Nancy E. Jones, PhD, Neuren Pharmaceuticals

Next Steps

Based on these results and feedback from clinical experts in Fragile X syndrome, Neuren is strongly encouraged to advance to the next step in clinical development. This will likely involve a study in younger children with Fragile X syndrome and may examine a longer treatment duration with higher doses. This next study will also refine the outcome measures that may be used in a Phase 3 study (clinical trial phases explained here).


Read Neuren’s press release

neuren Fragile X trial result graph

Explore Current Fragile X Research

FRAXA-funded researchers around the world are leading the way towards effective treatments and ultimately a cure.

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