FDA Grants Newron Rare Pediatric Disease Designation for Sarizotan in Rett Syndrome

Rare Daily Staff

The U.S. Food and Drug Administration granted Newron Pharmaceuticals Rare Pediatric

Disease designation for sarizotan, the company’s experimental therapy for the rare genetic neurological disorder Rett syndrome. 

Rett syndrome is a non-inherited, genetic, post-natal, progressive neurodevelopmental disorder that occurs almost exclusively in girls and leads to severe impairments, affecting nearly every aspect of the child’s life. The hallmark of Rett syndrome is near constant repetitive hand movements while awake. The disease is characterized by normal early growth and development (6 to 18 months) followed by a slowing of development, loss of purposeful use of the hands, distinctive hand movements, autistic features, slowed brain and head growth, ataxia, seizures, and intellectual disability. There is currently no cure for Rett syndrome.

Sarizotan, licensed from Merck KGaA, is a highly selective compound for specific serotonin or dopamine receptors that modulates the activity of these neurotransmitters in the brain. Sarizotan was originally developed in another indication, and was licensed with an extensive safety and tolerability data package.

Sarizotan targets respiratory disturbances as the primary efficacy outcome in the ongoing STARS pivotal study to evaluate the efficacy, safety and tolerability of sarizotan in patients with Rett syndrome suffering from respiratory symptoms. In preclinical evaluation studies, the full agonist at the serotonergic 5HT1A receptor has demonstrated dramatic improvement of respiration in a number of genetic mouse models of Rett.

At the end of October, Newron partnered with the global Rett community to sponsor the first International Rett Syndrome Burden of Illness Survey, which is meant to assess the overall burden of Rett syndrome on patients and stakeholders.

The FDA grants Rare Pediatric Disease designation for serious or life-threatening diseases with manifestations in individuals aged from birth to 18 years, including access to the FDA’s expedited review and approval process. The designation makes sarizotan eligible for a Rare Pediatric Disease Priority Review voucher upon approval of the therapy by the FDA.

The vouchers can be used to reduce the time of an FDA new drug approval review to six months from ten months. The vouchers are potentially lucrative because they are transferable. Most recently, Swedish Orphan Biovitrum sold its Priority Review voucher to AstraZeneca for $95 million.

“The decision of the FDA to designate sarizotan for the treatment of a rare pediatric population, following an earlier decision to grant it an Orphan Drug designation, highlights the critical need within the Rett community for treatments for this devastating disease,” said Ravi Anand, Newron’s chief medical officer. The company expects results from the STARS study within the next few weeks.

Photo: Ravi Anand, chief medical officer of Newron

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