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Ruzurgi FDA Approval History

Last updated by Judith Stewart, BPharm on July 4, 2022.

FDA Approved: Yes (Tentative Approval) (First approved May 6, 2019)
Brand name: Ruzurgi
Generic name: amifampridine
Dosage form: Tablets
Company: Jacobus Pharmaceutical Company Inc.
Treatment for: Lambert-Eaton Myasthenic Syndrome

Ruzurgi (amifampridine) is a potassium-channel blocker indicated for the treatment of Lambert-Eaton myasthenic syndrome (LEMS) in patients 6 years to less than 17 years of age.

Update: On February 3, 2022, Catalyst Pharmaceuticals, Inc. reported that the FDA marketing approval previously granted for Ruzurgi is no longer valid. In Catalyst's Lawsuit against the FDA, the District Court ruled that the FDA's approval of Ruzurgi violated Catalyst's exclusivity for Firdapse (amifampridine phosphate) under the Orphan Drug Act.

  • Ruzurgi is the first treatment approved specifically for LEMS in pediatric patients.
  • Amifampridine was also approved under the brand name Firdapse (amifampridine phosphate) in November 2018 as a treatment for LEMS in adults.
  • The $375,000 per year price tag that came with Catalyst Pharmaceuticals' Firdapse sparked outrage among LEMS patients, as they had previously been able to access the drug for free through an FDA compassionate use program.1
  • Ruzurgi is expected to be available at a much lower cost than Firdapse.
  • Although Ruzurgi is approved for use in pediatric patients, the FDA decision does make it possible for physicians to prescribe the drug off-label to adults.
1. Senator Sanders asks why drug, once free, now costs $375k Accessed May 21, 2019 at

Development timeline for Ruzurgi

Feb  3, 2022Catalyst Pharmaceuticals Reports that the FDA Marketing Approval Previously Granted for Ruzurgi is No Longer Valid
May  6, 2019Approval FDA Approves Ruzurgi (amifampridine) for Children with Lambert-Eaton Myasthenic Syndrome

Further information

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