Ganaxolone Gets Priority Review for CDKL5 Deficiency Disorder

The application is supported by data from the phase 3 Marigold study.

The Food and Drug Administration (FDA) has accepted for Priority Review the New Drug Application for ganaxolone for the treatment of seizures associated with cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder.

CDKL5 deficiency disorder is a rare genetic disorder that results in difficult-to-control seizures and severe neurodevelopmental delay. Ganaxolone, a positive allosteric modulator of GABAA receptors, is designed to regulate brain activity by inhibiting the abnormal electrical discharges that cause seizures and status epilepticus.

The application is supported by data from the randomized, placebo-controlled, double-blind phase 3 Marigold study ( Identifier: NCT03572933) that evaluated the efficacy and safety of adjunctive ganaxolone therapy in 101 patients aged 2 to 21 years with genetically confirmed CDKL5 gene mutation. Patients were randomly assigned 1:1 to receive either ganaxolone or placebo 3 times a day, in addition to their existing stable regimen, for 17 weeks.

Findings showed that treatment with ganaxolone resulted in a 30.7% median reduction in 28-day major motor seizure frequency (primary endpoint) compared with a 6.9% reduction with placebo (P =.0036). In an open-label extension study, patients treated with ganaxolone for at least 12 months (n=48) experienced a 49.6% median reduction in major motor seizure frequency. The most common adverse reaction reported with ganaxolone was somnolence.

“The FDA’s acceptance of our NDA submission is an important step toward potentially bringing the first approved therapy specifically for treatment of seizures associated with [CDKL5 deficiency disorder], a devastating disorder with high unmet medical need, to families and healthcare providers,” said Scott Braunstein, MD, CEO of Marinus Pharmaceuticals. “We believe that ganaxolone has the potential to provide meaningful clinical benefit for patients and we look forward to working closely with the FDA during the review process.”

A Prescription Drug User Fee Act target date of March 20, 2022 has been set for the application.


  1. Marinus Pharmaceuticals announces FDA acceptance for filing and Priority Review of New Drug Application for ganaxolone in CDKL5 deficiency disorder. News release. Marinus Pharmaceuticals, Inc. September 20, 2021. Accessed September 24, 2021.
  2. Science & Pipeline: About Ganaxolone. Marinus Pharmaceuticals, Inc. Accessed September 24, 2021.