What is the difference between Ruzurgi and Firdapse?
They both contain amifampridine, and they are both used to treat Lambert-Eaton myasthenic syndrome. What's the difference?
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3, 2022, Catalyst Pharmaceuticals, Inc. reported that the FDA marketing approval previously granted for Ruzurgi is no longer valid.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) |
Drug information
Related support groups
- Firdapse (2 questions, 3 members)
- Amifampridine (2 questions, 3 members)
- Ruzurgi (1 questions, 3 members)
- Lambert-Eaton Myasthenic Syndrome (2 questions, 3 members)
