What is the difference between Ruzurgi and Firdapse?

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Accepted Answer

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3, 2022, Catalyst Pharmaceuticals, Inc. reported that the FDA marketing approval previously granted for Ruzurgi is no longer valid.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 under the Orphan Drug Act.

Firdapse (amifampridine phosphate) and Ruzurgi (amifampridine) are both used to treat Lambert-Eaton myasthenic syndrome (LEMS).

Firdapse is approved to treat LEMS in adults and pediatric patients 6 years of age and older.

Ruzurgi was approved to treat LEMS in pediatric patients 6 years to less than 17 years of age.

Firdapse contains amifampridine as the phosphate salt, which is more stable than the base drug contained in Ruzurgi, and therefore does not require refrigeration.

Ruzurgi is also expected to be priced more competitively than Firdapse, which when first approved carried a price tag of $375,000 per year, causing outrage among LEMS patients who had previously been able to access amifampridine for free through an FDA compassionate use program.

Ruzurgi Firdapse Generic Name amifampridine amifampridine phosphate Date of FDA Approval May 6, 2019 November 28, 2018 Company Jacobus Pharmaceutical Company Inc. Catalyst Pharmaceuticals, Inc. Indication LEMS in pediatric patients 6 to less than 17 years of age LEMS in adults and pediatric
patients 6 years of age and older How Supplied Tablets 10 mg (functionally scored) Tablets 10 mg (functionally scored) Administration Ruzurgi can be taken without regard to food. Firdapse can be taken without regard to food. Dosing Tablets may be halved, or prepared as a 1 mg/mL suspension for patients who require a dose less than 5 mg. Tablets may be halved Storage and Handling Prior to Dispensing: Store Ruzurgi tablets in a refrigerator between 2°C to 8°C (36°F to 46°F). Keep container tightly closed with desiccant canister inside after opening. Protect from moisture and light.

After Dispensing: Store Ruzurgi tablets at 20°C to 25°C (68°F to 77°F) for up to 3 months; excursions permitted between 15°C to 30°C (59°F to 86°F)

Store Firdapse tablets at 20°C to 25°C (68°F to 77°F) with excursions permitted from 15°C to 30°C (59°F to 86°F)

What is the difference between Ruzurgi and Firdapse?

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	Ruzurgi	Firdapse
Generic Name	amifampridine	amifampridine phosphate
Date of FDA Approval	May 6, 2019	November 28, 2018
Company	Jacobus Pharmaceutical Company Inc.	Catalyst Pharmaceuticals, Inc.
Indication	LEMS in pediatric patients 6 to less than 17 years of age	LEMS in adults and pediatric patients 6 years of age and older
How Supplied	Tablets 10 mg (functionally scored)	Tablets 10 mg (functionally scored)
Administration	Ruzurgi can be taken without regard to food.	Firdapse can be taken without regard to food.
Dosing	Tablets may be halved, or prepared as a 1 mg/mL suspension for patients who require a dose less than 5 mg.	Tablets may be halved
Storage and Handling	Prior to Dispensing: Store Ruzurgi tablets in a refrigerator between 2°C to 8°C (36°F to 46°F). Keep container tightly closed with desiccant canister inside after opening. Protect from moisture and light. After Dispensing: Store Ruzurgi tablets at 20°C to 25°C (68°F to 77°F) for up to 3 months; excursions permitted between 15°C to 30°C (59°F to 86°F)	Store Firdapse tablets at 20°C to 25°C (68°F to 77°F) with excursions permitted from 15°C to 30°C (59°F to 86°F)