Catalyst Pharmaceuticals has enrolled the first patient in its MSK-002 trial, a Phase III clinical study evaluating the efficacy and safety of Firdapse (amifampridine phosphate) to treat patients with MuSK antibody positive Myasthenia Gravis (MuSK-MG).
The double-blind, placebo-controlled withdrawal trial aims to enrol around 60 patients.
Based on an agreement signed between Catalyst and the US Food and Drug Administration (FDA) in August last year, the trial is scheduled to be conducted at various clinical trial sites in the US and Italy.
Its primary endpoint includes the Myasthenia Gravis Activities of Daily Living (MG-ADL), with a secondary endpoint of Quantitative Myasthenia Gravis Score (QMG).
Responding to a request of the FDA, the trial will also include up to ten generalised myasthenia gravis patients who will be evaluated to achieve the same clinical endpoints.
However, this subgroup of patients will not be required to achieve statistical significance, with only summary statistics provided for this group.
The trial expects to complete patient enrolment in about 12 months.
Catalyst Pharmaceuticals chief medical officer Gary Ingenito said: “There is a significant unmet medical need to treat the symptoms of MuSK-MG, and these patients are eagerly awaiting a new treatment option.
“The previous Catalyst supported, proof-of-concept investigator-sponsored study in MuSK-MG patients showed impressive clinical improvement in multiple measures.”
MuSK-MG is a particularly severe form of myasthenia gravis that is estimated to affect nearly 3,000 to 4,800 patients in the US.
Currently, there are no approved effective therapies available for MuSK-MG.
Catalyst’s Firdapse previously received orphan drug designation from the FDA for the treatment of Myasthenia Gravis.