{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,31]],"date-time":"2026-07-31T14:17:59Z","timestamp":1785507479610,"version":"3.56.0"},"reference-count":5,"publisher":"Oxford University Press (OUP)","issue":"7","license":[{"start":{"date-parts":[[2026,7,31]],"date-time":"2026-07-31T00:00:00Z","timestamp":1785456000000},"content-version":"vor","delay-in-days":30,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,7,7]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Pharmacokinetic research of infliximab often relies on prospectively collected, long-term frozen serum samples. Although the effect of storage conditions on infliximab stability has been researched extensively, the influence of long-term storage on the reliability of infliximab concentration measurements remains unknown.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>In this proof-of-concept study, infliximab serum concentrations measured after 2, 5, and 8\u2009years of standardized frozen storage at \u221270\u2009\u00b0C were compared with paired samples analyzed directly after collection. Equivalence was assessed using a two one-sided tests framework with predefined margins of 80%-125%, in line with FDA equivalence guidance.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Equivalence was demonstrated at all three storage durations. Geometric mean ratios were 87.0% (90% CI, 80.9%-93.6%), 103.2% (90% CI, 90.3%-117.9%), and 99.3% (90% CI, 92.5%-106.6%) at 2, 5, and 8\u2009years, respectively, all within predefined equivalence margins. A statistically significant reduction was observed in the 2-year group (P\u2009=\u2009.010), though within equivalence bounds. No concentration-dependent bias was detected (P\u2009=\u2009.926), and Spearman correlation between fresh and frozen concentrations was high (\u03c1\u2009=\u20090.908, P\u2009&amp;lt;\u2009.001).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>Infliximab serum concentrations remain stable after long-term frozen storage of up to 8 years under standardized conditions, supporting the validity of deferred concentration analyses in prospectively stored serum samples.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1093\/ecco-jcc\/jjag113","type":"journal-article","created":{"date-parts":[[2026,7,31]],"date-time":"2026-07-31T13:48:46Z","timestamp":1785505726000},"source":"Crossref","is-referenced-by-count":0,"title":["Stability of infliximab serum concentrations during long-term frozen storage: a paired biobank study"],"prefix":"10.1093","volume":"20","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3599-3618","authenticated-orcid":false,"given":"Suzanne I","family":"Anjie","sequence":"first","affiliation":[{"name":"Department of Gastroenterology and Hepatology, Amsterdam UMC , Amsterdam,","place":["The Netherlands"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sarah","family":"van Zon","sequence":"additional","affiliation":[{"name":"Department of Gastroenterology and Hepatology, Amsterdam UMC , Amsterdam,","place":["The Netherlands"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Karien","family":"Bloem","sequence":"additional","affiliation":[{"name":"PurSang Diagnostiek, Biologics and Immunopathology Lab , Amsterdam,","place":["The Netherlands"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9600-1312","authenticated-orcid":false,"given":"Theo","family":"Rispens","sequence":"additional","affiliation":[{"name":"Sanquin Research , Amsterdam,","place":["The Netherlands"]},{"name":"Amsterdam Institute for Infection and Immunity , Amsterdam UMC, Amsterdam,","place":["The Netherlands"]},{"name":"Department of Molecular Cell Biology and Immunology, Amsterdam UMC, Vrije Universiteit Amsterdam , Amsterdam,","place":["The Netherlands"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Geert R","family":"D\u2019Haens","sequence":"additional","affiliation":[{"name":"Department of Gastroenterology and Hepatology, Amsterdam UMC , Amsterdam,","place":["The Netherlands"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","published-online":{"date-parts":[[2026,7,31]]},"reference":[{"key":"2026073109484074600_jjag113-B1","doi-asserted-by":"crossref","first-page":"1570","DOI":"10.1053\/j.gastro.2020.12.031","article-title":"STRIDE-II: An Update on the Selecting Therapeutic Targets in Inflammatory Bowel Disease (STRIDE) Initiative of the International Organization for the Study of IBD (IOIBD): determining therapeutic goals for treat-to-target strategies in IBD","volume":"160","author":"Turner","year":"2021","journal-title":"Gastroenterology"},{"key":"2026073109484074600_jjag113-B2","author":"Administration USFaD","year":"2019"},{"key":"2026073109484074600_jjag113-B3","doi-asserted-by":"crossref","first-page":"236","DOI":"10.1136\/flgastro-2016-100692","article-title":"Assays for measurement of TNF antagonists in practice","volume":"8","author":"Vande Casteele","year":"2017","journal-title":"Frontline 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Colitis"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/academic.oup.com\/ecco-jcc\/article-pdf\/20\/7\/jjag113\/70411407\/jjag113.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/academic.oup.com\/ecco-jcc\/article-pdf\/20\/7\/jjag113\/70411407\/jjag113.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,31]],"date-time":"2026-07-31T13:48:48Z","timestamp":1785505728000},"score":1,"resource":{"primary":{"URL":"https:\/\/academic.oup.com\/ecco-jcc\/article\/doi\/10.1093\/ecco-jcc\/jjag113\/8748390"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,7]]},"references-count":5,"journal-issue":{"issue":"7","published-print":{"date-parts":[[2026,7,7]]}},"URL":"https:\/\/doi.org\/10.1093\/ecco-jcc\/jjag113","relation":{},"ISSN":["1873-9946","1876-4479"],"issn-type":[{"value":"1873-9946","type":"print"},{"value":"1876-4479","type":"electronic"}],"subject":[],"published-other":{"date-parts":[[2026,7]]},"published":{"date-parts":[[2026,7]]},"article-number":"jjag113"}}