FDA grants orphan drug designation to Ketarx for Rett syndrome

Ketamine, an anesthetic that gives a feeling of detachment, is being studied

Andrea Lobo, PhD avatar

by Andrea Lobo, PhD |

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The U.S. Food and Drug Administration (FDA) has granted orphan drug designation to Ketarx (racemic ketamine) for treating Rett Syndrome.

The designation is awarded to products that show promise to prevent, diagnose, or treat rare diseases. Incentives for developers include seven years of market exclusivity after approval, potential tax credits for clinical trials, and waiving the regulatory approval fee.

PharmaTher Holdings is developing new uses, delivery methods and dosage forms of ketamine.

“We are committed to unlocking the potential of KETARX for rare disorders, and the addition of the Rett syndrome program to our four FDA-approved orphan drug designations strengthens our position in leading the advancement of ketamine for unmet medical needs in mental health, neurological and pain disorders,” said Fabio Chianelli, CEO of PharmaTher, in a press release.

Rett syndrome is usually caused by mutations in the MECP2 gene The gene provides instructions for producing the MeCP2 protein, which is involved in regulating the brain’s development and function. Symptoms include communication issues, anxiety, repetitive hand movements, and seizures.

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The gene is located on the X chromosome and occurs almost exclusively in girls. Because boys only have one X chromosome, if they have the mutated form of the MECP2 gene they have no healthy MECP2 gene copy to compensate for mutations and usually don’t survive infancy. Those who do survive have more severe symptoms.

There is no cure or approved treatment for Rett syndrome. Ketamine, a dissociative anesthetic that provides a feeling of detachment from one’s surroundings, first showed potential for Rett syndrome by researchers at Case Western Reserve University (CWRU) under the leadership of David M. Katz, PhD, professor emeritus at the school of medicine. A low dose of ketamine (8 mg/kg) was shown to acutely reverse disease-related abnormalities in female mice with Rett-like disease.

Further research suggested ketamine might promote the repair of nerve cell communication in Rett syndrome, according to PharmaTher.

A Phase 2 clinical trial (NCT03633058) assessed the safety and effectiveness of oral ketamine in 24 girls with Rett syndrome, ages 6 to 12. The girls were randomly assigned to receive it either at 0.75 or 1.5 mg/kg for five days, along with five days of a placebo.

The results of this study, yet to be published, will be analyzed to support a potential Phase 3 clinical trial and to obtain FDA agreement on a regulatory plan for approval.

The company previously announced a partnership with CWRU to develop and market ketamine for Rett syndrome.