Pyridostigmine and amifampridine evaluated versus placebo in myasthenia gravis

Almost a century after Dr Mary Walker first used pyridostigmine to treat autoimmune myasthenia gravis:

• the randomised, randomised, double-blind IMPACT-MG trial in the Netherlands compared the anticholinesterase alone (in 19 patients), then in combination with amifampridine (20 patients), versus placeboLe placebo est un produit dont la présentation est identique à celle d’un médicament, mais qui ne contient pas de principe actif. Dans un essai clinique, un placebo est utilisé pour mesurer l’action réelle du médicament testé, en comparant les effets du médicament testé contenant le principe actif et ceux du placebo., in 5-day periods separated by 2-day washout periods;
• the investigators concluded that pyridostigmine was superior in terms of efficacy (MGII, QMG, MG-ADL, MG-QoL15r) and lower annual societal costs for pyridostigmine compared with placebo.
• Amifampridine (30 or 60 mg) added to pyridostigmine was not shown to be more effective than pyridostigmine alone;
• however, it was associated with a higher incidence of adverse effects (paraesthesia, dizziness, sleep disturbances, etc.).

Efficacy of Pyridostigmine in Myasthenia Gravis: A Randomized, Double-Blind, Placebo-Controlled Crossover Trial. Remijn-Nelissen L, Bakker WR, van den Hout WB et al. Neurology. 2026 Apr 28;106(8):e214865.

 

Efficacy and Safety of Amifampridine in Myasthenia Gravis: A Randomized, Double-Blind, Placebo-Controlled Crossover Trial. Remijn-Nelissen L, Bakker WR, van Gelder T et al. Neurology. 2026 Apr 28;106(8):e214715.