Catalyst wants to increase maximum daily dosage of Firdapse for LEMS

Catalyst Pharmaceuticals wants to increase the maximum recommended daily dosage of Firdapse (amifampridine), its Lambert-Eaton myasthenic syndrome (LEMS) treatment, to 100 mg.

Plans are underway to ask the U.S. Food and Drug Administration (FDA) to approve the new dose, the company announced in a press release detailing its fourth quarter and full year 2022 financial results.

At the moment, Firdapse’s label allows a maximum dosage of 80 mg daily in adults and children weighing 45 kg (99 pounds) or more. In children weighing less than 45 kg, the dosage is not to exceed 40 mg daily.

The medication was the first oral therapy approved in the U.S. to treat symptoms of LEMS. It remains the only approved treatment for patients ages 6 and older after a federal appeals court decision struck down the FDA’s approval of Ruzurgi for pediatric patients. Ruzurgi has the same active ingredient as the Catalyst treatment, but its approval was canceled for violating Firdapse’s market exclusivity rights.

As part of the Catalyst’s plans to expand the availability of Firdapse to Asian countries, a Phase 3 clinical study is ongoing in Japan. That trial, being run by Catalyst’s partner, DyDo Pharma, is expected to be completed by the end of the year.

The company anticipates filing an application requesting authorization to market the medicine in Japan in the second quarter of 2024, should the study’s safety and efficacy data be positive.

“We will continue to drive organic growth across our product portfolio while capturing synergies with the Firdapse franchise to capitalize on the compelling revenue potential of our expanding product portfolio,” said Patrick J. McEnany, chairman and CEO of Catalyst.

LEMS occurs when nerve cells fail to send proper signals to muscles instructing them to contract, causing them to weaken over time. Firdapse works by helping to restore nerve cells’ ability to send these signals to muscles, which in turn is expected to enhance muscle strength.

We will continue to drive organic growth across our product portfolio while capturing synergies with the Firdapse franchise to capitalize on the compelling revenue potential of our expanding product portfolio.

Following the purchase of Ruzurgi mid last year, Catalyst got two additional patents to add to its intellectual property estate. These should support Firdapse’s long-term commercial potential to 2037.

In reporting its financials for 2022, Catalyst Pharmaceuticals noted net product revenue of $61 million for Firdapse in the fourth quarter. The company stated that those revenues represent “robust growth of a 59% increase compared to Q4 2021.”

“We remain confident in our ability to accelerate our business’s growth potential as we continue to evaluate opportunities to further expand our product portfolio with clinically differentiated medicines in rare neurological and epileptic diseases,” McEnany said. “We believe that our expanding patent portfolio is solid and we will vigorously defend and prosecute any and all infringers.”