[Efficacy and safety of low-dose cyclophosphamide plus corticosteroids for type I/II myasthenia gravis].

Objective To evaluate the efficacy and safety of low-dose cyclophosphamide plus corticosteroids for type Ⅰ / Ⅱ myasthenia gravis (MG).Methods This trial was prospective,non-random and open-labeled.We selected 160 patients with steroid-insensitive MG from January 1999 to October 2011.Each patient received an oral dose of prednisone 0.5 mg · kg-1 · d-1,cyclophosphamide 8 mg· kg-1 time-1 once weekly intravenously and oral pyridostigmine 36 mg · kg-1 · d-1.The efficacies were assessed by absolute and relative MG scores.The clinical treatment cycle was 30 weeks.Results (1) Among them,74/106 type Ⅰ MG patients (69.9％) reached clinical relative scores ≥95％ in 30 weeks.The total dose of cyclophosphamide was 12 g.And 35/54 type Ⅱ MG patients (64.8％) reached clinical relative scores ≥95％ in 30 weeks.No statistically significant difference existed between two groups (P =0.521).(2)All patients had various degrees of improvement in 30 weeks.The difference was statistically significant by Mann-Whitney U test (P ≤ 0.05).(3) There were minor side effects in these all patients.(4) When the total dose of cyclophosphamide reached 4 g,the cure rate in type Ⅰ patients was higher than that of in type Ⅱ patients (P=0.000).When the total dose of cyclophosphamide reached 12 g,the cure rate in type Ⅱ patients was higher than that of in type Ⅰ patients (P =0.001).(5) The cure dose of cyelophosphamide was 4-8 g in 58.4％ of type Ⅰ patients versus 8-12 g in 61.1％ of type Ⅱ patients.Conclusion The combined treatment of low-dose cyclophosphamide and corticosteroids in glucocorticoid-insensitive type MG (type Ⅰ / Ⅱ) is both effective and safe.And the sensitivity to cyclophosphamide varies for different clinical types.It is higher in type Ⅰ than type Ⅱpatients. Key words: Myasthenia gravis;  Cyclophosphamide;  Immunosuppressant;  Treatment