Amifampridine phosphate (Firdapse(®)) is effective and safe in a phase 3 clinical trial in LEMS.
OBJECTIVE
We evaluated the efficacy and safety of amifampridine phosphate (Firdapse(®)) for symptomatic treatment in Lambert-Eaton myasthenic syndrome (LEMS).


METHODS
Phase 3, randomized, double-blind, study. Patients were treated initially with amifampridine phosphate for 7-91 days, followed by randomization to continue amifampridine phosphate for 14 days or placebo (7-day taper, 7-day placebo). The primary efficacy endpoints were changes from baseline at day 14 in Quantitative Myasthenia Gravis and Subject Global Impression scores.


RESULTS
The coprimary efficacy end points and 1 of the secondary efficacy end points were met, showing a significant benefit of aminfampridine phosphate over placebo at Day 14. All 5 primary, secondary, and tertiary endpoints achieved statistical significance at Day 8. Amifampridine phosphate was well tolerated; the most common adverse events were oral and digital paresthesias, nausea, and headache.


CONCLUSIONS
This study provides Class I evidence of efficacy of amifampridine phosphate as a symptomatic treatment for LEMS.
['Oh|Shin J|SJ|', 'Shcherbakova|Natalya|N|', 'Kostera-Pruszczyk|Anna|A|', 'Alsharabati|Mohammad|M|', 'Dimachkie|Mazen|M|', 'Blanco|Jose Munoz|JM|', 'Brannagan|Thomas|T|', 'Lavrnić|Dragana|D|', 'Shieh|Perry B|PB|', 'Vial|Christophe|C|', 'Meisel|Andreas|A|', 'Komoly|Samuel|S|', 'Schoser|Benedikt|B|', 'Sivakumar|Kumaraswamy|K|', 'So|Yuen|Y|', '|||']
D015761:4-Aminopyridine D000328:Adult D000368:Aged D000369:Aged, 80 and over D000077770:Amifampridine D015220:Calcium Channels D004311:Double-Blind Method D005260:Female D006801:Humans D015624:Lambert-Eaton Myasthenic Syndrome D008297:Male D008875:Middle Aged D053580:Muscle Strength D010710:Phosphates D026902:Potassium Channel Blockers D016896:Treatment Outcome D055815:Young Adult
Amifampridine phosphate LEMS Lambert-Eaton myasthenic syndrome 3,4-DAP 3,4-diaminopyridine Potassium channel blockers Small cell lung cancer (SCLC)