{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,21]],"date-time":"2026-08-21T20:25:37Z","timestamp":1787343937900,"version":"build-2736575974"},"reference-count":46,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,8,21]],"date-time":"2026-08-21T00:00:00Z","timestamp":1787270400000},"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. Neurol."],"abstract":"<jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Efgartigimod is a human immunoglobulin (IgG1) antibody Fc fragment that reduces IgG levels through neonatal Fc receptor blockade. ADAPT-SC+\u202fassessed the long-term safety, tolerability, and efficacy of subcutaneous (SC) efgartigimod PH20 in adult participants with generalized myasthenia gravis (gMG). Previously, ADAPT-SC demonstrated noninferiority of efgartigimod PH20 SC to intravenous efgartigimod.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>ADAPT-SC+\u202fwas a single-arm, multicenter, open-label extension study. Efgartigimod PH20 SC 1000\u202fmg was administered in treatment cycles of 4 once-weekly injections, with timing of cycles individualized based on clinical evaluation. During the first year of the study, \u22654\u202fweeks were required between cycles; in the second year and onward, participants consenting to a protocol amendment could have \u22651\u202fweek between cycles.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>A total of 184 participants rolled over from ADAPT+ and ADAPT-SC, and 180 participants received \u22651 dose of efgartigimod PH20 SC. The mean (SD) treatment plus follow-up time was 2.6 (0.9) years, corresponding to 459.4 total participant years of follow-up, with a maximum of 33 treatment cycles. Overall, 169 (93.9%) participants experienced \u22651 treatment-emergent adverse event (TEAE), and the most frequent TEAEs were injection site reactions (ISRs; n\u202f=\u202f83, 46.1%), COVID-19 (n\u202f=\u202f53, 29.4%), and headache (n\u202f=\u202f48, 26.7%). ISRs were mild or moderate in severity. No new safety signals were observed in participants with more frequent dosing (&amp;lt;4\u202fweeks between cycles) after the protocol amendment. Rapid and clinically meaningful improvements (CMI, reduction of \u22652 points) in mean Myasthenia Gravis Activities of Daily Living (MG-ADL) total scores were observed. During the study, 95.1% of participants with acetylcholine receptor antibody\u2013positive (AChR-Ab+) gMG and 94.7% of participants with AChR-Ab\u2212 gMG achieved CMI at any point. Many participants demonstrated substantial clinical improvements, with 59.2% of participants with AChR-Ab+ gMG and 34.2% of participants with AChR-Ab\u2212 gMG achieving minimal symptom expression (MSE; MG-ADL, 0\u20131). The majority of participants who achieved MSE (83.3% with AChR-Ab+ gMG, 53.8% with AChR-Ab\u2212 gMG) experienced sustained MSE at consecutive assessments covering \u22658\u202fweeks.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Discussion<\/jats:title>\n                    <jats:p>The results of ADAPT-SC+\u202fdemonstrate long-term safety, tolerability, and sustained efficacy of efgartigimod PH20 SC across various dosing approaches, building on previous studies to broaden options for individualizing treatment for patients with gMG.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Clinical trial registration<\/jats:title>\n                    <jats:p>\n                      <jats:ext-link>https:\/\/clinicaltrials.gov\/study\/NCT04818671<\/jats:ext-link>\n                      , NCT04818671.\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fneur.2026.1876344","type":"journal-article","created":{"date-parts":[[2026,8,21]],"date-time":"2026-08-21T19:46:24Z","timestamp":1787341584000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Long-term safety, tolerability, and efficacy of subcutaneous efgartigimod PH20 in generalized myasthenia gravis: final results from a phase 3 open-label extension study (ADAPT-SC+)"],"prefix":"10.3389","volume":"17","author":[{"given":"Andreas","family":"Meisel","sequence":"first","affiliation":[{"name":"Department of Neurology, Charit\u00e9 \u2013 Universit\u00e4tsmedizin Berlin","place":["Berlin, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Carlo","family":"Antozzi","sequence":"additional","affiliation":[{"name":"Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta","place":["Milan, Italy"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ratna","family":"Bhavaraju-Sanka","sequence":"additional","affiliation":[{"name":"Department of Neurology, University of Texas Health Science Center at San Antonio","place":["San Antonio, TX, United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jan L.","family":"De Bleecker","sequence":"additional","affiliation":[{"name":"Department of Neurology, Ghent University Hospital","place":["Ghent, Belgium"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wan-Yi","family":"Huang","sequence":"additional","affiliation":[{"name":"argenx","place":["Ghent, Belgium"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rosa Hermina","family":"Jimenez","sequence":"additional","affiliation":[{"name":"argenx","place":["Ghent, Belgium"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fien M.","family":"Verhamme","sequence":"additional","affiliation":[{"name":"argenx","place":["Ghent, Belgium"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ming","family":"Jiang","sequence":"additional","affiliation":[{"name":"argenx","place":["Ghent, Belgium"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Li","family":"Liu","sequence":"additional","affiliation":[{"name":"argenx","place":["Ghent, Belgium"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Denis","family":"Korobko","sequence":"additional","affiliation":[{"name":"State Budgetary Healthcare Institution of Novosibirsk Region \u201cThe State Novosibirsk Regional Clinical Hospital\u201d","place":["Novosibirsk, Russia"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anna","family":"Kostera-Pruszczyk","sequence":"additional","affiliation":[{"name":"Department of Neurology, Medical University of Warsaw","place":["Warsaw, Poland"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kimiaki","family":"Utsugisawa","sequence":"additional","affiliation":[{"name":"Department of Neurology, Hanamaki General Hospital","place":["Hanamaki, Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jan J. 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