July 9, 2019 – Jacobus Pharmaceuticals has launched Ruzurgi® (amifampridine), a potassium channel blocker indicated for the treatment of Lambert-Eaton myasthenic syndrome (LEMS) in patients who are at least six years old and less than 17 years of age. The product received U.S. FDA approval in May 2019.
A rare autoimmune disease, LEMS occurs when the immune system attacks calcium channels on nerve endings. This reduces the body’s ability to release acetylcholine, a chemical required to trigger muscle contraction. The lack of acetylcholine leads to muscle weakness. In 50-60% of cases, LEMS is associated with an underlying disease—usually small cell lung cancer—but in 40-50% of cases, there is no known cause. The disease typically affects adults, but in some cases may also affect children.
All patients on Ruzurgi should receive it in up to five divided doses per day. For patients who weigh 45kg (99 pounds) or more, the recommended initial dosage is 15mg to 30mg daily, in divided doses. The dosage can be increased daily in 5mg to 10mg increments if needed, up to a maximum single dose of 30mg and a maximum daily dose of 100mg. Recommended initial dosing for patients who weigh less than 45kg is 7.5mg to 15mg daily. The dosage can be increased daily in 2.5mg to 5mg increments with a maximum single dose of 15mg and a maximum daily dose of 50mg. For patients who have renal or hepatic impairment, or who are known N-acetyltransferase 2 poor metabolizers, the lowest recommended dosage should be used.
Ruzurgi contains the same active ingredient as Catalyst Pharmaceuticals’ Firdapse® (amifampridine), which received FDA approval in 2018. While both products are indicated to treat LEMS, Firdapse is not approved for use in pediatric patients, and Ruzurgi requires refrigeration where Firdapse does not. In June 2019, Catalyst initiated a lawsuit against the FDA, seeking invalidation of Ruzurgi’s approval.
Prior to Firdapse’s FDA approval, Jacobus had made amifampridine available to patients at no cost under an FDA-sanctioned compassionate use program for a number of years. Catalyst drew criticism in 2018 when it set Firdapse’s average list price at $375,000 per year. Jacobus announced intentions to set a lower price for Ruzurgi upon its approval, and the product will be available at a wholesale acquisition cost (WAC) of approximately $288,000 per year for a patient taking the maximum daily dose.