{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,15]],"date-time":"2026-04-15T18:09:23Z","timestamp":1776276563294,"version":"3.50.1"},"reference-count":25,"publisher":"BMJ","issue":"2","funder":[{"DOI":"10.13039\/501100014034","name":"foreum","doi-asserted-by":"crossref","id":[{"id":"10.13039\/501100014034","id-type":"DOI","asserted-by":"crossref"}]},{"DOI":"10.13039\/501100004785","name":"NordForsk","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100004785","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["RMD Open"],"accepted":{"date-parts":[[2019,9,29]]},"published-print":{"date-parts":[[2019,10]]},"abstract":"<jats:sec>\n                  <jats:title>Objective<\/jats:title>\n                  <jats:p>Although clinical trials support equivalence of originator products and biosimilars for etanercept and infliximab, real-world studies among biologics-na\u00efve patients with spondyloarthritis (SpA) are lacking. The objectives were to compare treatment retention in biologics-na\u00efve patients with SpA starting either the originator product or a biosimilar of infliximab and etanercept, and to explore the baseline characteristics of these patients.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Methods<\/jats:title>\n                  <jats:p>Patients with SpA (ankylosing spondylitis\/non-radiographical axial SpA\/undifferentiated SpA), starting infliximab or etanercept as their first-ever biological disease-modifying antirheumatic drug during January 2014\u2013June 2017 were identified in five Nordic biologics\u2013rheumatology registers. Baseline characteristics were retrieved from each registry; comorbidity data were identified through linkage to national health registers. Country-specific data were pooled, and data on infliximab and etanercept were analysed separately. Comparisons of treatment retention between originators and biosimilars were assessed through survival probability curves, retention rates (2 years for infliximab\/1\u2009year for etanercept) and Hazard Ratios (HR).<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Results<\/jats:title>\n                  <jats:p>We included 1319 patients starting infliximab (24% originator\/76% biosimilar), and 1015 patients starting etanercept (49% originator\/51% biosimilar). Baseline characteristics were largely similar for the patients treated with the originators compared with the corresponding biosimilars. Survival probability curves were highly similar for the originator and its biosimilar, as were retention rates: infliximab 2-year retention originator, 44% (95% CI 38% to 50%)\/biosimilar, 46% (95% CI: 42% to 51%); and etanercept 1-year retention originator, 66% (95% CI 61% to 70%)\/biosimilar, 73% (95% CI 68% to 78%). HRs were not statistically significant.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Conclusion<\/jats:title>\n                  <jats:p>This observational study of biologics-na\u00efve patients with SpA from five Nordic countries showed similar baseline characteristics and very similar retention rates in patients treated with originators versus biosimilars, for both infliximab and etanercept, indicating comparable effectiveness in clinical practice.<\/jats:p>\n               <\/jats:sec>","DOI":"10.1136\/rmdopen-2019-001079","type":"journal-article","created":{"date-parts":[[2019,10,24]],"date-time":"2019-10-24T08:59:39Z","timestamp":1571907579000},"page":"e001079","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":17,"title":["Treatment retention of infliximab and etanercept originators versus their corresponding biosimilars: Nordic collaborative observational study of 2334 biologics na\u00efve patients with spondyloarthritis"],"prefix":"10.1136","volume":"5","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2250-9348","authenticated-orcid":false,"given":"Ulf","family":"Lindstr\u00f6m","sequence":"first","affiliation":[{"name":"Department of Rheumatology and Inflammation Research, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8931-8482","authenticated-orcid":false,"given":"Bente","family":"Glintborg","sequence":"additional","affiliation":[{"name":"DANBIO and Copenhagen Center for Arthritis Research (COPECARE), Center for Rheumatology and Spine Diseases, Centre of Head and Orthopedics, Rigshospitalet Glostrup, Glostrup, Denmark"},{"name":"Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Daniela","family":"Di Giuseppe","sequence":"additional","affiliation":[{"name":"Clinical Epidemiology Unit, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Dan","family":"Nordstr\u00f6m","sequence":"additional","affiliation":[{"name":"Department of Medicine, Helsinki University and Helsinki University Hospital, Helsinki, Finland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sella","family":"Aarrestad Provan","sequence":"additional","affiliation":[{"name":"Rheumatology, Diakonhjemmet Hospital, Oslo, Norway"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Bjorn","family":"Gudbjornsson","sequence":"additional","affiliation":[{"name":"Centre for Rheumatology Research, University Hospital and Faculty of Medicine, University of Iceland, Reykjavik, Iceland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Johan","family":"Askling","sequence":"additional","affiliation":[{"name":"Clinical Epidemiology Unit, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Merete","family":"Lund Hetland","sequence":"additional","affiliation":[{"name":"DANBIO and Copenhagen Center for Arthritis Research (COPECARE), Center for Rheumatology and Spine Diseases, Centre of Head and Orthopedics, Rigshospitalet Glostrup, Glostrup, Denmark"},{"name":"Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Kalle","family":"Aaltonen","sequence":"additional","affiliation":[{"name":"Pharmaceuticals Pricing Board, Ministry of Social Affairs and Health, Helsinki, Finland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Niels Steen","family":"Krogh","sequence":"additional","affiliation":[{"name":"Zitelab Aps, Copenhagen, Denmark"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Arni Jon","family":"Geirsson","sequence":"additional","affiliation":[{"name":"Department of Rheumatology, University Hospital, Reykjavik, Iceland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lennart T H","family":"Jacobsson","sequence":"additional","affiliation":[{"name":"Department of Rheumatology and Inflammation Research, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"239","published-online":{"date-parts":[[2019,10,23]]},"reference":[{"key":"2025090312322209000_5.2.e001079.1","doi-asserted-by":"publisher","DOI":"10.1136\/annrheumdis-2012-203090"},{"key":"2025090312322209000_5.2.e001079.2","doi-asserted-by":"publisher","DOI":"10.1136\/annrheumdis-2012-203091"},{"key":"2025090312322209000_5.2.e001079.3","doi-asserted-by":"publisher","DOI":"10.1136\/annrheumdis-2015-207588"},{"key":"2025090312322209000_5.2.e001079.4","unstructured":"European Medicines Agency . Available: http:\/\/www.ema.europa.eu\/ema\/ [Accessed Aug 2019]."},{"key":"2025090312322209000_5.2.e001079.5","doi-asserted-by":"publisher","DOI":"10.1136\/annrheumdis-2015-208783"},{"key":"2025090312322209000_5.2.e001079.6","doi-asserted-by":"crossref","unstructured":"Emery P , Vencovsk\u00fd J , Sylwestrzak A , et al . Long-term efficacy and safety in patients with rheumatoid arthritis continuing on SB4 or switching from reference etanercept to SB4. 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A systematic review of double-blinded versus open-label studies","volume":"24","author":"Odinet","year":"2018","journal-title":"J Manag Care Spec Pharm"},{"key":"2025090312322209000_5.2.e001079.17","doi-asserted-by":"publisher","DOI":"10.1001\/jama.297.11.1233"},{"key":"2025090312322209000_5.2.e001079.18","doi-asserted-by":"crossref","first-page":"465","DOI":"10.1080\/03009742.2018.1444199","article-title":"Biological treatment in ankylosing spondylitis in the Nordic countries during 2010-2016: a collaboration between five biological registries","volume":"47","author":"Glintborg","year":"2018","journal-title":"Scand J Rheumatol"},{"key":"2025090312322209000_5.2.e001079.19","doi-asserted-by":"crossref","first-page":"499","DOI":"10.1080\/14712598.2018.1458089","article-title":"Uptake of rheumatology biosimilars in the absence of forced switching","volume":"18","author":"Di Giuseppe","year":"2018","journal-title":"Expert Opin Biol Ther"},{"key":"2025090312322209000_5.2.e001079.20","unstructured":"RADS . The Danish regions rads guidelines for use of biosimilar infliximab and etanercept. Available: http:\/\/www.regioner.dk\/media\/3488\/rads-notat-om-anvendelsen-af-biosimilaere-juni-2016.pdf [Accessed Aug 2019]."},{"key":"2025090312322209000_5.2.e001079.21","doi-asserted-by":"publisher","DOI":"10.1177\/1403494811401482"},{"key":"2025090312322209000_5.2.e001079.22","doi-asserted-by":"crossref","DOI":"10.1186\/1471-2458-11-450","article-title":"External review and validation of the Swedish national inpatient register","volume":"11","author":"Ludvigsson","year":"2011","journal-title":"BMC Public Health"},{"key":"2025090312322209000_5.2.e001079.23","doi-asserted-by":"publisher","DOI":"10.1136\/annrheumdis-2016-209166"},{"key":"2025090312322209000_5.2.e001079.24","doi-asserted-by":"crossref","unstructured":"Kay J , D\u00f6rner T , Emery P , et al . Clinical trial and \u2018real-world\u2019 data support switching from a bio-originator to its biosimilar. 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