{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,17]],"date-time":"2026-08-17T23:24:03Z","timestamp":1787009043697,"version":"build-2736575974"},"reference-count":18,"publisher":"Oxford University Press (OUP)","issue":"4","license":[{"start":{"date-parts":[[2020,1,20]],"date-time":"2020-01-20T00:00:00Z","timestamp":1579478400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/journals\/pages\/open_access\/funder_policies\/chorus\/standard_publication_model"}],"funder":[{"name":"Astellas Pharma, Inc."}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2020,4,1]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:sec>\n                    <jats:title>Background<\/jats:title>\n                    <jats:p>Fidaxomicin is a recommended treatment for Clostridioides difficile infection (CDI) and reduces CDI recurrence incidence versus vancomycin. An extended-pulsed fidaxomicin (EPFX) regimen further reduces recurrence frequency. However, the pharmacokinetic profile of fidaxomicin in an EPFX regimen is unknown.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Objectives<\/jats:title>\n                    <jats:p>To evaluate plasma and stool concentrations of fidaxomicin and its metabolite, OP-1118, after EPFX administration for CDI.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>In the Phase 3b\/4 EXTEND trial, patients aged \u226560\u2009years with toxin-confirmed CDI were randomized to receive EPFX (oral fidaxomicin twice daily, Days 1\u20135; once daily on alternate days, Days 7\u201325). Fidaxomicin and OP-1118 concentrations were determined using post-dose plasma samples obtained on Days 5\u205f\u00b1\u205f1, 12\u205f\u00b1\u205f1 and 25\/26, and post-dose stool samples obtained on Days 5\u205f\u00b1\u205f1, 12\u205f\u00b1\u205f1 and 26\u205f\u00b1\u205f1.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Plasma samples from 14 patients were included in the pharmacokinetic analysis; 12 of these patients provided stool samples. Median (range) plasma concentrations of fidaxomicin on Day 5\u205f\u00b1\u205f1 and Day 25\/26 were 0.0252 (0.0038\u20130.1220) mg\/L and 0.0069 (0\u20130.0887) mg\/L, respectively, and those of OP-1118 were 0.0648 (0.0142\u20130.3250) mg\/L and 0.0206 (0\u20130.3720) mg\/L, respectively. Median (range) stool concentrations of fidaxomicin and OP-1118 on Day 26\u205f\u00b1\u205f1 were 272.5 (0\u2013524) mg\/kg and 280.5 (0\u20131120) mg\/kg, respectively.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>EPFX treatment maintained fidaxomicin stool concentrations above the C. difficile MIC90 until Day 26\u205f\u00b1\u205f1. Systemic exposure to fidaxomicin and OP-1118 was low throughout and there was no evidence of accumulation in plasma or stool during treatment.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1093\/jac\/dkz549","type":"journal-article","created":{"date-parts":[[2020,1,3]],"date-time":"2020-01-03T07:09:04Z","timestamp":1578035344000},"page":"1014-1018","source":"Crossref","is-referenced-by-count":9,"title":["Pharmacokinetic analysis of an extended-pulsed fidaxomicin regimen for the treatment of Clostridioides (Clostridium) difficile infection in patients aged 60 years and older in the EXTEND randomized controlled trial"],"prefix":"10.1093","volume":"75","author":[{"given":"Benoit","family":"Guery","sequence":"first","affiliation":[{"name":"Infectious Diseases Service, Department of Medicine, University Hospital and University of Lausanne, Lausanne, 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