Following Firdapse US Launch, Catalyst Estimates 2019 Revenues of $102M

Catalyst Pharmaceuticals expects to report 2019 net product revenues of $102 million for Firdapse (amifampridine), the first and only therapy available for treating the symptoms of Lambert-Eaton myasthenic syndrome (LEMS).

In addition, the biopharmaceutical company anticipates 2020 Firdapse net product revenues of $135 million to $155 million. Catalyst plans to introduce unspecified programs this year to help LEMS patients and their healthcare providers.

“Catalyst has completed its first year as a commercial-stage company following the successful U.S. launch of Firdapse (amifampridine) for the treatment of adult LEMS patients last January,” Patrick J. McEnany, chairman and CEO at Catalyst, said in a press release.

“In reviewing the launch metrics that we established, we are pleased that Catalyst has exceeded all expectations for product revenues and the number of patients who are currently being treated with Firdapse, including the many individuals who for the first time have received a medicine to treat Lambert-Eaton myasthenic syndrome,” McEnany said.

LEMS is an autoimmune disease that affects the neuromuscular junction, which is the area where nerve cells and muscle fibers communicate. It is characterized by muscle weakness, diminished reflexes, and fatigue.

The disease develops because the body produces autoantibodies — immune proteins that mistakenly target and react with a person’s own tissues or organs — against voltage-gated calcium channels (VGCC) found at the end of nerve cells. Those channels normally allow nerve cells to take up calcium, needed for the release of a neurotransmitter called acetylcholine, which is a chemical messenger that triggers muscle contraction. The acetylcholine is released into the neuromuscular junction, where it helps nerve cells communicate with muscle cells and control their movement.

Originally developed by BioMarin, Firdapse is a small-molecule therapy that blocks another channel, called the voltage-dependent potassium channel, that’s found in nerve cells. This causes the opening of any remaining healthy VGCCs, allowing calcium ions to flow into the nerve cells. That, in turn, restores the release of acetylcholine and improves muscle function.

In the U.S., Firdapse became the first therapy for the symptomatic treatment of LEMS, in patients ages 17 and older, when it was approved by the U.S. Food and Drug Administration in 2018. The treatment had been approved by the European Commission in 2009 for commercial use in Europe.

Catalyst amended its license agreement for Firdapse in May 2019 to expand its commercial territory to Japan. The company now is seeking to expand the use of Firdapse for other disorders, including myasthenia gravis and spinal muscular atrophy type 3.