To determine the efficacy of cyclophosphamide (CPP) in refractory myasthenia gravis (MG) in the Mexican population.

We included all the patients with refractory MG treated at our institution with CPP: 30-50 mg/kg monthly for at least 6 months. The efficacy was assessed clinically with the Osserman scale, with a difference of 1 being significant. The assessment included the search for adverse effects. Frequency analysis was carried out. The results obtained were expressed in percentages, some data were described using measures of central tendency. The relapse-free and remission-free period was also calculated using the Kaplan-Meyer statistic.

8 patients were identified (7F:1M). According to Osserman scale in 75% of the patients (6/8 cases) there was clinical improvement. The remaining 25% maintained in the initial grade, even after six months of treatment. One of the patients showed relapse at six months of follow-up; while the rest of the cases remained stable after six months of follow-up. According to the Kaplan-Meyer analysis the median survival-free period of relapse was 9 (6.2-11.5) months and the median remission onset was 4 (1-8) months.