{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,28]],"date-time":"2026-09-28T05:57:12Z","timestamp":1790575032246,"version":"4.1.0"},"reference-count":9,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,9,28]],"date-time":"2026-09-28T00:00:00Z","timestamp":1790553600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Immunol."],"abstract":"<jats:p>Lambert-Eaton myasthenic syndrome (LEMS) is a rare autoimmune disorder, associated with neoplastic disease in 50-60% of cases. In severe cases, currently available immunomodulatory therapies frequently fail to achieve adequate control. We report a 20-year-old woman with non-tumor LEMS refractory to 3,4-diaminopyridine, sequential immunosuppression with prednisone, azathioprine, mycophenolate mofetil and rituximab and plasma exchange, who remained severely disabled after two years of progressive disease. Off-label efgartigimod (1000mg subcutaneously weekly for four weeks, with the interval between cycles initially adjusted according to symptom recurrence), produced rapid and sustained clinical improvement, including recovery from a respiratory decompensation episode. The Myasthenia Gravis Activities of Daily Living (MG-ADL) score decreased from a baseline of 5\u20139 to a minimum of 2, and the Quantitative Myasthenia Gravis (QMG) score improved from 13\u201318 to 8-11. Symptoms consistently recurred toward the end of the third week of each treatment-free interval, prompting a fixed two-week interval, which stabilized clinical response and reduced fluctuation severity. This is, to our knowledge, the first report of sustained clinical benefit from FcRn inhibition in non-paraneoplastic, long-standing refractory LEMS. As in myasthenia gravis, LEMS is mediated by pathogenic circulating IgG antibodies, and these findings support FcRn inhibition as a rational treatment strategy in refractory LEMS regardless of tumor association.<\/jats:p>","DOI":"10.3389\/fimmu.2026.1954344","type":"journal-article","created":{"date-parts":[[2026,9,28]],"date-time":"2026-09-28T05:44:27Z","timestamp":1790574267000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Case Report: Efgartigimod in refractory non-tumor Lambert-Eaton myasthenic syndrome"],"prefix":"10.3389","volume":"17","author":[{"given":"Ana","family":"Baltasar-Corral","sequence":"first","affiliation":[{"name":"Neurology Department, Hospital Universitario Ram\u00f3n y Cajal","place":["Madrid, Spain"]},{"name":"Instituto Ram\u00f3n y Cajal de Investigaci\u00f3n Sanitaria - IRYCIS","place":["Madrid, Spain"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nuria","family":"Garc\u00eda-Barrag\u00e1n","sequence":"additional","affiliation":[{"name":"Neurology Department, Hospital Universitario Ram\u00f3n y Cajal","place":["Madrid, Spain"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Beatriz","family":"Zarza-Sanz","sequence":"additional","affiliation":[{"name":"Neurology Department, Hospital Universitario Ram\u00f3n y Cajal","place":["Madrid, Spain"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Francisco Javier","family":"Buis\u00e1n-Catevilla","sequence":"additional","affiliation":[{"name":"Neurology Department, Hospital Universitario Ram\u00f3n y Cajal","place":["Madrid, Spain"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Beatriz","family":"Montero-Llorente","sequence":"additional","affiliation":[{"name":"Pharmacy Department, Hospital Universitario Ram\u00f3n y Cajal","place":["Madrid, Spain"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Miguel Angel","family":"Rodr\u00edguez-Sagrado","sequence":"additional","affiliation":[{"name":"Pharmacy Department, Hospital Universitario Ram\u00f3n y Cajal","place":["Madrid, Spain"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jaime","family":"Masjuan-Vallejo","sequence":"additional","affiliation":[{"name":"Neurology Department, Hospital Universitario Ram\u00f3n y Cajal","place":["Madrid, Spain"]},{"name":"Instituto Ram\u00f3n y Cajal de Investigaci\u00f3n Sanitaria - IRYCIS","place":["Madrid, Spain"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rodrigo","family":"\u00c1lvarez-Velasco","sequence":"additional","affiliation":[{"name":"Neurology Department, Hospital Universitario Ram\u00f3n y Cajal","place":["Madrid, Spain"]},{"name":"Instituto Ram\u00f3n y Cajal de Investigaci\u00f3n Sanitaria - IRYCIS","place":["Madrid, Spain"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,9,28]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.1016\/B978-0-12-823912-4.00012-8","article-title":"Lambert-Eaton myasthenic syndrome","volume":"200","author":"Lipka","year":"2024","journal-title":"Handb Clin Neurol"},{"key":"B2","doi-asserted-by":"publisher","DOI":"10.1212\/WNL.0000000000008747","article-title":"Long-term follow-up, quality of life, and survival of patients with Lambert-Eaton myasthenic syndrome","volume":"94","author":"Lipka","year":"2020","journal-title":"Neurology"},{"key":"B3","doi-asserted-by":"publisher","DOI":"10.1200\/JCO.2010.32.0440","article-title":"Clinical Dutch-English Lambert-Eaton Myasthenic syndrome (LEMS) tumor association prediction score accurately predicts small-cell lung cancer in the LEMS","volume":"29","author":"Titulaer","year":"2011","journal-title":"J Clin Oncol"},{"key":"B4","doi-asserted-by":"publisher","DOI":"10.1016\/S1474-4422(21)00159-9","article-title":"Safety, efficacy, and tolerability of efgartigimod in patients with generalised myasthenia gravis (ADAPT): a multicentre, randomised, placebo-controlled, phase 3 trial","volume":"20","author":"Howard Jr Bril","year":"2021","journal-title":"Lancet Neurol"},{"key":"B5","doi-asserted-by":"publisher","DOI":"10.1007\/s40120-026-00932-0","article-title":"Digital monitoring of patients with generalized myasthenia gravis: A prospective pilot study","volume":"15","author":"Vesperinas","year":"2026","journal-title":"Neurol Ther"},{"key":"B6","doi-asserted-by":"publisher","DOI":"10.1007\/s40263-024-01090-3","article-title":"FcRn inhibitor therapies in neurologic diseases","volume":"38","author":"Alfaidi","year":"2024","journal-title":"CNS Drugs"},{"key":"B7","doi-asserted-by":"publisher","DOI":"10.1080\/1744666X.2025.2497840","article-title":"Safety profile of efgartigimod from global clinical trials across multiple immunoglobulin G-mediated autoimmune diseases","volume":"21","author":"Gwathmey","year":"2025","journal-title":"Expert Rev Clin Immunol"},{"key":"B8","doi-asserted-by":"publisher","first-page":"520","DOI":"10.1007\/s00415-025-13258-y","article-title":"Efgartigimod for the treatment of Lambert-Eaton syndrome: a case report","volume":"272","author":"Zhang","year":"2025","journal-title":"J Neurol"},{"key":"B9","doi-asserted-by":"publisher","DOI":"10.2147\/IMCRJ.S555977","article-title":"Case report: A patient with Lambert-Eaton myasthenic syndrome successfully treated with efgartigimod","volume":"18","author":"Han","year":"2025","journal-title":"Int Med Case Rep J"}],"container-title":["Frontiers in Immunology"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fimmu.2026.1954344\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,28]],"date-time":"2026-09-28T05:44:27Z","timestamp":1790574267000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fimmu.2026.1954344\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,28]]},"references-count":9,"alternative-id":["10.3389\/fimmu.2026.1954344"],"URL":"https:\/\/doi.org\/10.3389\/fimmu.2026.1954344","relation":{},"ISSN":["1664-3224"],"issn-type":[{"value":"1664-3224","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,28]]},"article-number":"1954344"}}