{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,12]],"date-time":"2026-10-12T05:46:40Z","timestamp":1791784000739,"version":"4.3.4"},"reference-count":26,"publisher":"Wiley","license":[{"start":{"date-parts":[[2026,10,11]],"date-time":"2026-10-11T00:00:00Z","timestamp":1791676800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"},{"start":{"date-parts":[[2026,10,11]],"date-time":"2026-10-11T00:00:00Z","timestamp":1791676800000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["acrjournals.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Arthritis &amp; Rheumatology"],"abstract":"<jats:sec>\n                    <jats:title>Objective<\/jats:title>\n                    <jats:p>Information is limited on the natural history and current treatment patterns in macrophage activation syndrome (MAS), a life\u2010threatening hyperinflammatory syndrome complicating Still's disease (systemic juvenile idiopathic arthritis [sJIA] and adult\u2010onset Still's disease [AOSD]). AMETHYST aimed to describe real\u2010world treatment patterns and outcomes in glucocorticoid (GC)\u2013refractory MAS complicating Still's disease.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>In this retrospective cohort study, medical data from January 1, 2012, to March 31, 2023, were abstracted from charts of all eligible patients across eight sites in Europe, Canada, and the United States for index MAS episodes (occurring between January 1, 2012, and September 30, 2022, and meeting eligibility criteria).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Overall, 55 of 64 included patients (86%) had sJIA and 9 of 64 (14%) had AOSD. Most patients (53\/64 [82.8%]) were children at index (median age: 7.0 years). MAS was characterized by rash (60.4%), fever (52.8%), and hepatic involvement (49.1%). All patients received GCs; most were also treated with anakinra (48\/64 [75%]) and\/or ciclosporin (33\/64 [51.6%]). Normalization of seven (complete MAS laboratory remission) or at least three (partial remission) prespecified laboratory parameters occurred in 7 of 64 (10.9%) and 41 of 64 patients (64.1%), respectively. GCs were tapered in 50 of 64 patients (78.1%) (median: 39.9 days). Per investigator assessment of clinical signs\/symptoms for the index MAS episode, 24 of 64 (37.5%) and 26 of 64 patients (40.6%) had a complete and partial response, respectively. MAS recurred in 20 of 64 patients (31.3%). Seven of 64 patients (10.9%) died, and the estimated one\u2010year survival probability was 93.75%.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Low MAS laboratory remission rates and toxicities of high\u2010dose GCs combined with other treatments highlight the need for safer, more effective therapies.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1002\/art.70326","type":"journal-article","created":{"date-parts":[[2026,9,7]],"date-time":"2026-09-07T09:26:31Z","timestamp":1788773191000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["<scp>AMETHYST<\/scp>\n                    : A Retrospective Cohort Study of Treatment Patterns and Outcomes in Patients With Glucocorticoid\u2010Refractory Macrophage Activation Syndrome Complicating Still's Disease"],"prefix":"10.1002","author":[{"given":"Alexei","family":"Grom","sequence":"first","affiliation":[{"name":"Division of Rheumatology Cincinnati Children's Hospital Medical Center  Cincinnati Ohio"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8792-4219","authenticated-orcid":false,"given":"Jordi","family":"Ant\u00f3n","sequence":"additional","affiliation":[{"name":"Department of Pediatric Rheumatology ERN RITA Center, Hospital Sant Joan de D\u00e9u Barcelona  Barcelona Spain"},{"name":"Health Sciences School, Universitat de Barcelona  Barcelona Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Edward M.","family":"Behrens","sequence":"additional","affiliation":[{"name":"Children's Hospital of Philadelphia  Philadelphia Pennsylvania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Corey","family":"Best","sequence":"additional","affiliation":[{"name":"Sobi, Inc  Waltham Massachusetts"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9419-1690","authenticated-orcid":false,"given":"Norbert","family":"Blank","sequence":"additional","affiliation":[{"name":"Division of Rheumatology, Department of Internal Medicine Heidelberg University Hospital  Heidelberg Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Josefin","family":"Blomkvist","sequence":"additional","affiliation":[{"name":"Sobi  Stockholm Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3837-5337","authenticated-orcid":false,"given":"Scott W.","family":"Canna","sequence":"additional","affiliation":[{"name":"Children's Hospital of Philadelphia  Philadelphia Pennsylvania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sonia","family":"Carriqu\u00ed","sequence":"additional","affiliation":[{"name":"Department of Pediatric Rheumatology ERN RITA Center, Hospital Sant Joan de D\u00e9u Barcelona  Barcelona Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shanmuganathan","family":"Chandrakasan","sequence":"additional","affiliation":[{"name":"Division of Bone and Marrow Transplant, Aflac Cancer and Blood Disorders Center Children's Healthcare of Atlanta and Emory University  Atlanta Georgia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andrew","family":"Danquah","sequence":"additional","affiliation":[{"name":"Sobi Ltd  Great Abington United Kingdom"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ngoc\u2010Bao","family":"Duong","sequence":"additional","affiliation":[{"name":"Clinical Research Unit Necker Hospital  Paris France"},{"name":"Universit\u00e9 Paris\u2010Cit\u00e9  Paris France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Brian D.","family":"Jamieson","sequence":"additional","affiliation":[{"name":"Sobi, Inc  Morrisville North Carolina"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Paivi","family":"Miettunen","sequence":"additional","affiliation":[{"name":"Department of Pediatrics University of Calgary  Calgary Alberta Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Abiola","family":"Oladapo","sequence":"additional","affiliation":[{"name":"Sobi, Inc  Waltham Massachusetts"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3489-1756","authenticated-orcid":false,"given":"Sampath","family":"Prahalad","sequence":"additional","affiliation":[{"name":"Departments of Pediatrics and Human Genetics Emory University School of Medicine and Children's Healthcare of Atlanta  Atlanta Georgia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pierre","family":"Quartier","sequence":"additional","affiliation":[{"name":"Universit\u00e9 Paris\u2010Cit\u00e9  Paris France"},{"name":"Department of Paediatric Hematology\u2010Immunology and Rheumatology, Reference Centre for Rheumatic, Autoimmune, and Systemic Diseases in Children Necker\u2010Enfants Malades Hospital, AP\u2010HP  Paris France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5923-7051","authenticated-orcid":false,"given":"Grant","family":"Schulert","sequence":"additional","affiliation":[{"name":"Division of Rheumatology Cincinnati Children's Hospital Medical Center  Cincinnati Ohio"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anna","family":"Stoltenberg","sequence":"additional","affiliation":[{"name":"Sobi  Stockholm Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Uwe","family":"Ullmann","sequence":"additional","affiliation":[{"name":"Sobi  Basel Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Erika","family":"Van Nieuwenhove","sequence":"additional","affiliation":[{"name":"Department of Pediatric 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