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

Donald B. Sanders, Vern C. Juel, Yadollah Harati, A. Gordon Smith, Amanda C. Peltier, Tessa Marburger, Jau Shin Lou, Robert M. Pascuzzi, David P Richman, Tai Xie, Valentin Demmel, Laura R. Jacobus, Kathy L. Aleš, David P. Jacobus

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


Introduction: 3,4-diaminopyridine has been used to treat Lambert-Eaton myasthenia (LEM) for 30 years despite the lack of conclusive evidence of efficacy. Methods: We conducted a randomized double-blind placebo-controlled withdrawal study in patients with LEM who had been on stable regimens of 3,4-diaminopyridine base (3,4-DAP) for≥3 months. The primary efficacy endpoint was >30% deterioration in triple timed up-and-go (3TUG) times during tapered drug withdrawal. The secondary endpoint was self-assessment of LEM-related weakness (W-SAS). Results: Thirty-two participants were randomized to continuous 3,4-DAP or placebo groups. None of the 14 participants who received continuous 3,4-DAP had>30% deterioration in 3TUG time versus 72% of the 18 who tapered to placebo (P<0.0001). W-SAS similarly demonstrated an advantage for continuous treatment over placebo (P<0.0001). Requirement for rescue and adverse events were more common in the placebo group. Discussion: This trial provides significant evidence of efficacy of 3,4-DAP in the maintenance of strength in LEM.

Original languageEnglish (US)
JournalMuscle and Nerve
StateAccepted/In press - Jan 1 2018


  • 3,4-diaminopyridine
  • Amifampridine
  • Clinical trial
  • Eaton-Lambert syndrome
  • Efficacy
  • ELS
  • Lambert-Eaton myasthenia
  • Lambert-Eaton myasthenic syndrome
  • Lambert-Eaton syndrome
  • LEMS
  • LES
  • Timed up-and-go

ASJC Scopus subject areas

  • Physiology
  • Clinical Neurology
  • Cellular and Molecular Neuroscience
  • Physiology (medical)


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