Lupin’s Firdapse generic wins FDA approval, pending patent resolution
Catalyst Pharmaceuticals still hold exclusive rights to Firdapse in US
The U.S. Food and Drug Administration (FDA) has tentatively approved Lupin’s generic version of Firdapse (amifampridine) for people with Lambert-Eaton myasthenic syndrome (LEMS), ages 6 and older, according to a company press release.
This means the treatment satisfies all the requirements to be marketed in the U.S. as a Firdapse generic, a medication that has the same active ingredients, safety, and efficacy profile as a brand name reference product. However, final approval is pending on the expiration of patents that give Catalyst Pharmaceuticals exclusive marketing rights for Firdapse in the U.S., or resolution of litigation related to those patents. Should Lupin’s product reach the U.S. market, the company said it would be manufactured at its facility in Goa, India.
LEMS is an autoimmune disease wherein the immune system mistakenly attacks voltage-gated calcium channels (VGCCs), which are proteins on nerve cell endings needed for the proper communication between nerve and muscle cells.
The flow of calcium into nerve cells through VGCCs stimulates the release of acetylcholine, a signaling molecule, which triggers the muscles to contract. Without enough VGCCs, too little acetylcholine is released and muscles don’t receive the appropriate signals to contract, resulting in symptoms of muscle weakness and fatigue.
The active ingredient in Firdapse, amifampridine, helps any remaining VGCCs stay open, letting more calcium enter nerve cells. This should boost acetylcholine release, increasing muscle strength.
Firdapse and its generics
Firdapse, which comes in 10 mg oral tablets, was approved by the FDA in 2018 for treating LEMS patients, ages 17 and older, but its label was expanded in 2022 to include patients as young as 6. It was originally developed by BioMarin Pharmaceutical, which markets Firdapse in Europe, but Catalyst owns the licensing rights in North America and other areas.
Generic versions of medications contain the same active ingredient as their brand name alternative, with the same dosage, strength, and route of administration. They’re also expected to have the same safety and efficacy profile, but are usually sold at a lower price.
In the U.S., generics are reviewed through abbreviated new drug applications, or ANDAs, that don’t require full clinical trial data to support the treatment’s safety and efficacy profile. They do have to establish bio-equivalence, or proof that the generic has the same pharmacological properties and would work virtually identically to the reference medication, however.
While the FDA’s approval means Lupin’s generic has met that mark, Catalyst still holds active patents that protect Firdapse in the U.S., barring generics from hitting the market.
Catalyst has been involved in lawsuits related to these patents with multiple Firdapse generic developers, including Lupin. The company reported earlier this year that litigation with Lupin and another generic developer, Hetero, was ongoing.
Catalyst reached a settlement with Teva Pharmaceuticals under which Teva won’t market its own Firdapse generic until 2035. Teva had initially asked the FDA to authorize marketing of the generic in 2023, arguing that the patents were not valid or enforceable, which prompted a patent infringement lawsuit from Catalyst.
In another case, the FDA initially approved Jacobus Pharmaceutical’s Ruzurgi, which also contains amifampridine, to treat LEMS patients, ages 6 to less than 17, but the approval was invalidated after Catalyst won a court case related to the matter. Catalyst later acquired the U.S. rights to Ruzurgi as part of a settlement with Jacobus, but the treatment remains unavailable in the U.S.
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