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Catalyst Pharmaceuticals Conducting Trial to Test Amifampridine Phosphate (FIRDAPSE®) in Children with Congenital Myasthenic Syndromes

Statement from Catalyst: Amifampridine phosphate in CMS Clinical Trial

Researchers are looking for children, ages 2 to 17 years, with congenital myasthenic syndrome (CMS) to participate in a new phase 3 study being conducted by Catalyst Pharmaceuticals to test the experimental drug amifampridine phosphate.

Amifampridine phosphate, a potassium channel inhibitor, prolongs nerve signals allowing for greater stimulation of the muscle, and is expected to help treat muscle weakness in CMS patients.

The goals of the study are to determine the safety and tolerability of amifampridine phosphate  in children with CMS and to assess clinical efficacy, based on improvements in scores for measurements called subject global impression (SGI) and motor function measure (MFM 20 or 32).

Study participants will receive treatment two to four times per day and be assessed for improvement while taking amifampridine phosphate. After study completion, participants will be eligible for an expanded access program in which they will be able to continue to receive the drug.

Participants may be male or female, ages 2 (with a body weight greater than or equal to 10 kg) to 17 years.

Genetically-confirmed CMS mutations that may be eligible for the study include those involving:

  • acetylcholine receptor defect
  • Rapsyn deficiency
  • MuSK deficiency
  • SNAP25B deficiency
  • snap channel syndrome

Patients whose CMS has not been genetically confirmed will have genetic testing done at screening. Additional eligibility criteria will be reviewed with each patient’s physician.

There are a limited number of study sites in the U.S., but travel costs may be provided for those who are eligible and willing to travel.

For additional information on this trial, visit information and enter NCT02562066 into the search box. If you or someone you know may be interested in participating in the study, please contact Steven Bramer, Ph.D., at or (301) 473-3109.

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