Phase 2 Rett Syndrome Study Shows Promise

James Radke

A possible treatment for Rett Syndrome just completed another milestone. Neuren Pharmaceuticals announced their phase 2, placebo-controlled study was successful, showing the drug NNZ-2566 to be safe, well tolerated, and effective.

Neuron intends to submit applications to the U.S. Food and Drug Administration (FDA) for both Orphan Drug and Breakthrough Therapy designation and the Australian based company plans to meet with the FDA in early 2015 to discuss the next steps.

Rett syndrome is a rare neurological disorder that occurs almost exclusively in girls and leads to lifelong neurological impairments. Most are unable to speak or walk, but the hallmark sign of Rett syndrome is the constant repetitive hand movements. Rett syndrome is caused by mutations on the gene MECP2 on the X chromosome. NNZ-2566 is a synthetic analog of a neurotrophic peptide. In animal models, it inhibits neuroinflammation, normalizes the role of microglia, and corrects deficits in synaptic function. It is in phase 2 clinical trials to test its effectiveness in patients with Rett syndrome, Fragile X syndrome, and mild traumatic brain injury (concussion).

Phase 2 Study

The phase 2 double-blind, placebo-controlled study was conducted at Baylor College of Medicine (Drs. Daniel Glaze and Jeffery Neul), University of Alabama Birmingham (Dr. Alan Percy) and Gillette Children's Specialty Healthcare (Drs. Tim Feyma and Art Beisang). A total of 53 patients (16 – 45 years of age) completed the study that  compared the safety and tolerability of two doses of NNZ-2566 (35 and 70 mg/kg twice a day) with placebo. Numerous secondary outcomes to assess efficacy were also measured.

While details of the results are not yet available, in a press release, Neuren stated that patients given the 70 mg/kg dose showed a clinical benefit in a number of efficacy outcomes at both the group and individual level. In addition, NNZ-2566 was shown to be well tolerated at the dose levels tested after 28 days of treatment, and no significant safety concerns were identified.

Steven Kaminsky PhD, Chief Science Officer of said:

 “These are exciting times for Rett syndrome and this trial firmly sets our rudder in the water for the near future. The results will enable engagement with the FDA on the further development of NNZ-2566. This is what we, as the Rett community, have been hoping for. will continue to support Neuren in their goal to develop NNZ-2566 as a drug designated to treat Rett syndrome."

Clinical investigator, Alan Percy MD, Professor of Pediatric Neurology at the University of Alabama stated:

“The results of this trial suggest a very promising proof of concept as we continue on the pathway to develop a disease-altering treatment for girls and women with Rett syndrome. Not only was this short-term trial managed successfully, but also the data analyses were conducted in a very robust fashion.”

 Neuren plans to publish and present the results in the first half of 2015.
Neuren Executive Chairman, Richard Treagus added:

“We are very grateful to the patients and families affected by Rett syndrome, as well as the support provided by IRSF, that have made this ground-breaking clinical trial possible.  The trial results have exceeded our expectations and we look forward to discussing with the FDA the remaining requirements to develop NNZ-2566 for the treatment of Rett syndrome.”

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