Catalyst Pharmaceutical Partners has posted positive results from a study jointly funded with, and conducted by, BioMarin Pharmaceuticals to assess the cardiac safety of Firdapse tablets (amifampridine also known as 3,4-DAP). Firdapse is approved in the EU, where it is marketed by BioMarin. Firdapse is currently in Phase III development in the U.S. for Lambert-Eaton Myasthenic Syndrome (LEMS) by Catalyst.

The study met the pre-specified primary endpoint, demonstrating that at and above therapeutic levels, that Firdapse (administered as phosphate salt) had no effect on heart rate or cardiac depolarization. None of the study subjects developed new, clinically relevant electrocardiographic/morphological changes following administration of Firdapse. Additionally, there was no significant effect of Firdapse on cardiac repolarization as assessed using the QT interval.

At a pre-IND meeting in 2010, FDA requested thorough QT (TQT) study results for Firdapse at exposures higher than typical therapeutic levels be included as part of the clinical safety package in any NDA filed for 3,4-DAP.The randomized, double-blind study compared the effects of Firdapse at or above therapeutic concentrations to placebo on the QT interval in 59 healthy human volunteers.