Randomized Trial of Thymectomy in Myasthenia Gravis.
Wolfe GI., Kaminski HJ., Aban IB., Minisman G., Kuo HC., Marx A., Ströbel P., Mazia C., Oger J., Cea JG., Heckmann JM., Evoli A., Nix W., Ciafaloni E., Antonini G., Witoonpanich R., King JO., Beydoun SR., Chalk CH., Barboi AC., Amato AA., Shaibani AI., Katirji B., Lecky BR., Buckley C., Vincent A., Dias-Tosta E., Yoshikawa H., Waddington-Cruz M., Pulley MT., Rivner MH., Kostera-Pruszczyk A., Pascuzzi RM., Jackson CE., Garcia Ramos GS., Verschuuren JJ., Massey JM., Kissel JT., Werneck LC., Benatar M., Barohn RJ., Tandan R., Mozaffar T., Conwit R., Odenkirchen J., Sonett JR., Jaretzki A., Newsom-Davis J., Cutter GR., MGTX Study Group None.
BACKGROUND: Thymectomy has been a mainstay in the treatment of myasthenia gravis, but there is no conclusive evidence of its benefit. We conducted a multicenter, randomized trial comparing thymectomy plus prednisone with prednisone alone. METHODS: We compared extended transsternal thymectomy plus alternate-day prednisone with alternate-day prednisone alone. Patients 18 to 65 years of age who had generalized nonthymomatous myasthenia gravis with a disease duration of less than 5 years were included if they had Myasthenia Gravis Foundation of America clinical class II to IV disease (on a scale from I to V, with higher classes indicating more severe disease) and elevated circulating concentrations of acetylcholine-receptor antibody. The primary outcomes were the time-weighted average Quantitative Myasthenia Gravis score (on a scale from 0 to 39, with higher scores indicating more severe disease) over a 3-year period, as assessed by means of blinded rating, and the time-weighted average required dose of prednisone over a 3-year period. RESULTS: A total of 126 patients underwent randomization between 2006 and 2012 at 36 sites. Patients who underwent thymectomy had a lower time-weighted average Quantitative Myasthenia Gravis score over a 3-year period than those who received prednisone alone (6.15 vs. 8.99, P<0.001); patients in the thymectomy group also had a lower average requirement for alternate-day prednisone (44 mg vs. 60 mg, P<0.001). Fewer patients in the thymectomy group than in the prednisone-only group required immunosuppression with azathioprine (17% vs. 48%, P<0.001) or were hospitalized for exacerbations (9% vs. 37%, P<0.001). The number of patients with treatment-associated complications did not differ significantly between groups (P=0.73), but patients in the thymectomy group had fewer treatment-associated symptoms related to immunosuppressive medications (P<0.001) and lower distress levels related to symptoms (P=0.003). CONCLUSIONS: Thymectomy improved clinical outcomes over a 3-year period in patients with nonthymomatous myasthenia gravis. (Funded by the National Institute of Neurological Disorders and Stroke and others; MGTX ClinicalTrials.gov number, NCT00294658.).