Catalyst Using the Expanded Access Program to Conduct Phase IV Study with LEMS Patients

James Radke

Patients with Lambert-Eaton Myasthenic Syndrome (LEMS) may now have access – free access – to a drug in development for the condition. 

Catalyst Pharmaceuticals has announced they are offering an Expanded Access Program (EAP) for Firdapse™ (amifampridine phosphate tablets equivalent to 10 mg amifampridine). Eligible patients will be part of a Phase IV open label study the company is conducting as they complete the submission requirements for regulatory approval.

 Lambert-Eaton Myasthenic Syndrome (LEMS) is a rare autoimmune disease with the primary symptoms of muscle weakness. The muscle weakness in LEMS is caused by autoantibodies to voltage gated calcium channels leading to a reduction in the amount of acetylcholine released from nerve terminals.  One possible way to increase acetylcholine release is to prolong periods of depolarization at the nerve terminal. The potassium channel blocker amifampridine is believed to do this and it is the active ingredient of Firdapse.

Phase 3 Trial Results

Recent data indicates that Firdapse is safe and effective.  Last month, the company reported their pivotal phase 3 trial met its primary endpoint. The clinical trial was a double blind, randomized, "withdrawal trial" in which all patients were initially treated with Firdapse during a 91 day run-in period followed by treatment with either Firdapse or placebo (randomly assigned, about 1:1) during a 2 week randomization period. A total of 38 patients completed the 3 month run-in period and subsequent 2 week randomization period. A "withdrawal trial" is designed to see if the placebo group’s symptoms worsen more than the treatment groups.   What the trial found was:

Eligibility for Phase 4 Study (Expanded Access Program)

To be eligible for the program, patients must be 10 years or older and  have a diagnosis of: Lambert-Eaton Myasthenic Syndrome (LEMS), Congenital myasthenic syndrome (CMS), or Downbeat nystagmus and meet the inclusion and exclusion criteria. Patients should talk to their physician when considering enrollment in the Firdapse EAP and the physician should call 1-844-347-3277 (844-Firdapse). Additional information is available on the Catalyst website and (NCT02189720).
The inclusion/exclusion criteria are listed below.

Inclusion Criteria:

Exclusion Criteria:

The Cost

There is no cost to patients who are eligible. Catalyst Pharmaceutical has stated they will absorb all costs and the drug Firdapse will be shipped to the patient’s home on a periodic basis (usually 90 days’ supply). Costs for other diagnostic tests or routine medical treatment will need to be covered by the patient’s insurance or at the patient’s expense.

If Firdapse is approved by the FDA, Catalyst will work with EAP physicians to help their patients understand how to transition to the approved drug and make sure all patients who need Firdapse have access to the drug, regardless of their ability to pay.

Image of the neuromuscular junction courtesy wikimedia commons. 
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