Post hoc analysis of MGTX trial supports legitimacy of thymectomy in MG without thymoma

Diplopia, ptosis, swallowing disorder, fall of the neck, weakness of the limbs, each of these symptoms is suggestive of autoimmune myasthenia gravis if it fluctuates from one moment to the next. This pathology causes excessive exercise fatigue of the striated muscles related to a dysfunction of neuromuscular transmission, induced by specific autoantibodies. Thymectomy is part of the treatment of patients with thymoma (benign or malignant), which is present in approximately 20% of cases of myasthenia gravis. Thymectomy is also beneficial in patients without thymoma, and with anti-acetylcholine receptor autoantibodies (AChRs), as demonstrated in the MGTX trial in 100 adults.

A post hoc analysis of the data from this trial, published in July 2020, completes the list of benefits of thymectomy in this indication by showing for participants in the thymectomy – prednisone group, compared to those in the prednisone alone group:

  • rapid attainment of minimal manifestation status (MMS);
  • more frequent maintenance (64% versus 38%) of a long-lasting MMS (at least 6 months) after complete stop of prednisone, the decay phase of corticosteroid therapy being less often accompanied by relapses in the event of thymectomy;
  • the reduction (5% vs. 35%) to corticosteroid-sparing immunosuppressive therapy to achieve a long-term MMS.


Minimal manifestation status and prednisone withdrawal in the MGTX trial. Lee I, Kuo HC, Aban IB, et al. Neurology. 2020 Jul 1