After 2016 Rejection, Catalyst Wins Approval for LEMS Treatment Firdapse

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Florida-based Catalyst Pharmaceutical won regulatory approval for its treatment of a rare autoimmune disorder called Lambert-Eaton myasthenic syndrome (LEMS). The U.S. Food and Drug Administration (FDA) approval of the new oral drug, Firdapse (amifampridine), is the first ever approved for this disease.

Patrick J. McEnany, chairman and chief executive officer of Catalyst Pharmaceuticals, called the FDA’s approval of Firdapse a “crowning achievement” for Catalyst as it is an “important step forward” for the company as it transitions to “a premier neurological rare disease company.”

Firdapse was approved for treatment of adults with LEMS, disorder that affects the connection between nerves and muscles and causes weakness and other symptoms in affected patients. Firdapse is expected to be available to patients in the first quarter of 2019, the company said. LEMS affects approximately one in 100,000 people in the United States and about 3 million people globally. In LEMS, the body’s immune system attacks the connection between cells and muscles. The most common symptoms of the autoimmune disorder are proximal muscle weakness and fatigue. Symptoms can be life-threatening when the weakness involves respiratory muscles. Approximately 50 percent of LEMS patients have an underlying malignancy, which is typically small cell lung cancer, the company said.

Despite the approval, shares of Catalyst are down more than 12 percent in morning trading. As of 10:10 a.m., the stock was trading at $2.80 per share, down from its closing of $3.13 on Wednesday.

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It’s been a long road for U.S. approval. Firdapse has been available in Europe for LEMS patients since 2009. In Europe, Firdapse is marketed by BioMarin. In 2016, the FDA issued a Refusal to File letter to Catalyst for Firdapse. The FDA said at the time that the application was not sufficient and required additional information that required an additional Phase III trial.

McEnany said the approval of Firdapse is a “potentially transformative milestone” in the lives of patients with LEMS. The approval provides those patients with a new first-in-class-therapy, he said.

“We continue to prepare for what we hope will be a successful launch based on productive discussions with payers, our efforts in patient identification and our development of a field-based commercial infrastructure. Our Catalyst Pathways patient services program is designed to assist patients and physicians with education, clinical diagnostic tools and assistance in navigating the reimbursement landscape,” McEnany said in a statement.

Earlier this week there were false reports that Firdapse had been approved by the FDA. Those reports forced the company to issue a statement on Tuesday that the drug was still under review.

Citing a SunTrust analyst, Reuters said Firdapse is expected to generate about $325 million in annual revenue for Catalyst by 2025. The drug brought in about $20 million for BioMarin in Europe last year.

The approval of Firdapse was based on positive results from two Phase III studies that showed patients treated with the medication experienced rapid, significant and sustained improvements in muscle function. Additionally, the drug reduced weakness and fatigability in patients who received Firdapse, compared to those who received placebo. Firdapse had previously received Orphan Drug designation and Breakthrough Therapy designation, from the FDA, as well as Priority Review.

“This FDA approval marks the arrival of a first-in-class therapy for a rare and devastating condition with limited treatment options,” said Gary Ingenito, chief medical officer and head of regulatory affairs at Catalyst. “We also look forward to continuing to work with the FDA to evaluate other potential indications for Firdapse.”

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