Amifampridine phosphate (Firdapse^®) is effective and safe in a phase 3 clinical trial in LEMS

Abstract

This study provides Class I evidence of efficacy of amifampridine phosphate as a symptomatic treatment for LEMS.

3,4‐diaminopyridine in Lambert‐Eaton myasthenic syndrome: Concerns regarding presentation of previous studies

“…This study provided definite (class 1) evidence of efficacy of DAP phosphate over placebo as a symptomatic treatment of LEMS. In both studies, DAP base and phosphate were well tolerated without any serious side effects . Thus, the definitive objective evidence of efficacy of 3,4‐DAP was shown in these 2 studies, contrary to the claims by Sanders and colleagues …”

“…I have identified what I consider to be a major error in the study by Sanders and colleagues with regard to their comments about 2 previous studies . In the introductory section, they stated that “two other studies failed to provide definitive objective evidence of efficacy of 3,4‐DAP,” which is in contrast to the actual conclusions of those studies . Both of those studies were authored by me as the first author and published in this Journal, and showed definite statistical significance in end‐points in the double‐blind study with diaminopyridine (DAP) in one and DAP phosphate in the other.…”

“…The 2016 study was designed and sponsored by Catalyst Pharmaceuticals. DAP phosphate (Firdapse) was used . The trial was conducted at 18 centers.…”

3,4‐diaminopyridine base effectively treats the weakness of Lambert‐Eaton myasthenia

“…None of these studies were used to file for regulatory approval in the USA or in Europe. Other clinical studies failed to provide definitive objective evidence of efficacy of 3,4‐diaminopyridine …”

“…Other clinical studies failed to provide definitive objective evidence of efficacy of 3,4-diaminopyridine. 10,11 In 1990, the US Food and Drug Administration granted orphan designation to 3,4-diaminopyridine, and compassionate use of the free base formulation 3,4-DAP became available through physician-held investigational new drugs (IND) for named patients in the United States and through special governmental approvals in other countries. To provide definitive evidence of efficacy, we designed the 3,4-DAP Product Efficacy Research (DAPPER) trial, a prospective, placebo-controlled withdrawal study of 3,4-DAP in LEM.…”