Some positive news for Myasthenia Gravis (MG) patients. Catalyst Pharmaceuticals has reported that their clinical trial testing Firdapse (amifampridine phosphate) in MG patients with anti-MuSK antibodies (MuSK-MG) met its primary endpoint.
About the trial
The trial was a randomized, double blind, placebo-controlled, single site, outpatient study assessing Firdapse in patients with MuSK-MG, a rare sub-population of MG patients.
Seven patients were then randomized into one of two crossover treatment groups which consisted of three, one-week treatment periods.
The primary efficacy endpoint was change from baseline in total Quantitative Myasthenia Gravis (QMG) score and total Myasthenia Gravis Activities of Daily Living (MG-ADL) score at the 7th day of each period.
Patients demonstrated change from baseline in both QMG score (P = .0003) and MG-ADL score (P = .0006).
The drug was also well tolerated in this population of patients.
Approximately 5–8 % of MG patients test positive for antibodies against muscle-specific tyrosine kinase (MuSK). MuSK is a receptor tyrosine kinase required for the formation and maintenance of the neuromuscular junction.
In MG, antibodies block, alter, or destroy the acetylcholine receptors at the neuromuscular junction. The condition is usually treated with acetylcholinesterase inhibitors that can increase the concentration of acetylcholine at the neuromuscular junction.