Objective:

Our objective is to report on the efficacy and safety of autologous hematopoietic stem cell transplantation (HSCT) in refractory myasthenia gravis.

Background:

Patients with refractory MG have few treatment options. HSCT has been used to treat immune diseases, however, its use in the treatment of MG is not broadly considered.

Design/Methods:

Twenty-one patients who underwent HSCT for MG between were retrospectively reviewed. All patients had severe MG refractory to multiple therapies. Stem cells were mobilized with cyclophosphamide and granulocyte colony stimulating factor. The grafts were depleted of immune cells by selecting CD34+ cells. HSCT conditioning consisted of high dose cytoreductive therapy and anti-thymocyte globulin. The primary efficacy outcome was achieving Myasthenia Gravis Foundation of America Post-intervention Status (MGFA-PIS) of clinically stable remission or minimal manifestations without treatment and remaining as such until most recent follow-up. Primary safety outcome was death unrelated to MG. 

Results:

The median (range) time from MG diagnosis to HSCT was 4.0 years (1.9-21.8 years). The primary outcome was reached in 16 of 18 evaluable patients (88.9%) at a median of 1.7 years and maintained with a median follow-up of 6.7 years (range 1.0-21.9 years). Two remaining evaluable patients achieved the PIS of minimal manifestations but required ongoing anti-MG treatment. Three patients were not evaluable for the primary outcome: one due to confounding illness and two due to death within 100 days post-HSCT. The primary safety outcome was reached by 4 patients (19%) as two additional patients died without active MG at 8.6 and 9.4 years post-HSCT.

Conclusions:

After HSCT for refractory MG, most patients achieved sustained disease remission. However, HSCT-related mortality in medically complex MG patients may be high. Prospective studies investigating the efficacy and safety of HSCT in the treatment of refractory MG are warranted.