RUZURGI

What it is

RUZURGI contains 10 mg of amifampridine per tablet. Amifampridine is a broad-spectrum potassium channel blocker. This medicinal product is subject to additional monitoring in Australia.

Approved indications

— Treatment of Lambert-Eaton myasthenic syndrome (LEMS) in adults and children aged 6 years and above.

Dosing overview

Dosing should be individualised based on clinical circumstances, patient response, and patient population. The dose should be gradually titrated to the optimal effective dose with the minimum of side effects. The recommended oral dose is based on body weight. For patients weighing less than 45 kg, the initial dose is 5 mg to 10 mg daily in divided doses (2 to 3 times per day), titrated by daily increments of 2.5 mg to 5 mg divided in up to 5 doses per day, with a maximum recommended single dose of 10 mg and maximum total daily maintenance dose of 40 mg. For patients weighing 45 kg or more, the initial dose is 10 mg to 20 mg daily in divided doses (2 to 3 times per day), titrated by daily increments of 5 mg to 10 mg divided in up to 5 doses per day, with a maximum recommended single dose of 20 mg and maximum total daily maintenance dose of 80 mg. Some patients may benefit from a total daily dose of 100 mg. RUZURGI can be taken without regard to food.

Key safety warnings

RUZURGI can cause seizures. Seizures have been observed in patients with and without a history of seizures taking RUZURGI at the recommended doses, and at various times after initiation of treatment. RUZURGI should be used with caution when used concomitantly with drugs that are known to lower the seizure threshold. QTc interval prolongation has been observed at supratherapeutic doses (120 mg RUZURGI in 4 equal doses of 30 mg at 4-hour intervals) in a thorough QT study. Drugs that prolong the QTc increase the risk of torsade de pointes, a polymorphic ventricular tachyarrhythmia. Generally, the risk of torsade de pointes increases with the magnitude of QTc prolongation produced by a drug. Caution should be observed if RUZURGI is administered to patients who have risk factors for torsade de pointes and particularly in patients with the slow acetylator phenotype. Anaphylaxis has been reported in patients taking another aminopyridine; therefore, it may occur with RUZURGI. Some patients have experienced dizziness when being treated with RUZURGI. The effect of RUZURGI on the individual patient should be considered prior to driving or operating machinery.

Contraindications

RUZURGI is contraindicated in patients with a history of seizures. RUZURGI is contraindicated in patients who are taking other forms of amifampridine or other aminopyridines. RUZURGI is contraindicated in patients with hypersensitivity to amifampridine or another aminopyridine.

PBS listing

The 10 mg tablet is listed on the PBS with authority required restriction. The ex-manufacturer price is A$2719.56.

Regulatory history

RUZURGI amifampridine 10 mg tablet was first listed on the ARTG on 14 September 2021. The PBAC did not recommend RUZURGI for Lambert-Eaton myasthenic syndrome in November 2021, but recommended it in March 2022 for LEMS in adults and children aged six years and above.