{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,23]],"date-time":"2026-09-23T04:08:34Z","timestamp":1790136514473,"version":"4.0.1"},"reference-count":35,"publisher":"Wiley","license":[{"start":{"date-parts":[[2026,9,22]],"date-time":"2026-09-22T00:00:00Z","timestamp":1790035200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"},{"start":{"date-parts":[[2026,9,22]],"date-time":"2026-09-22T00:00:00Z","timestamp":1790035200000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["ascpt.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Clin Pharma and Therapeutics"],"abstract":"<jats:p>\n                    Abemaciclib increases serum creatinine by inhibiting renal tubular transporters rather than reducing true glomerular filtration rate, a phenomenon known as pseudo\u2010acute kidney injury. Creatinine\u2013cystatin C discrepancy and genetic determinants of this elevation remain insufficiently characterized in Japanese patients. This single\u2010center prospective observational study included 63 Japanese patients with breast cancer receiving abemaciclib. On\u2010treatment serum creatinine and cystatin C were measured in all patients, with pre\u2010treatment cystatin C available in 29. eGFR was calculated using the Japanese equations (eGFRcre, eGFRcys), and the discrepancy quantified as their difference and ratio. Associations between change in serum creatinine and renal transporter polymorphisms (\n                    <jats:italic>SLC22A2<\/jats:italic>\n                    rs316019,\n                    <jats:italic>SLC47A1<\/jats:italic>\n                    rs2289669, and\n                    <jats:italic>SLC47A2<\/jats:italic>\n                    rs12943590) were evaluated by hierarchical regression. Serum creatinine increased in 62 patients (median change, 0.21\u2009mg\/dL) and eGFRcre decreased by a median of 20.5\u2009mL\/min\/1.73\u2009m\n                    <jats:sup>2<\/jats:sup>\n                    , whereas on\u2010treatment eGFRcys exceeded eGFRcre by a median of 54.9\u2009mL\/min\/1.73\u2009m\n                    <jats:sup>2<\/jats:sup>\n                    (median ratio 2.07). Relative to baseline, the elevation was CTCAE grade 1 in 57 patients (90.5%) and grade 2 in 5 (7.9%), remained stable through week 24, and fell after drug interruption (0.87 to 0.71\u2009mg\/dL,\n                    <jats:italic>P<\/jats:italic>\n                    \u2009&lt;\u20090.001). In the 29\u2010patient sub\u2010cohort the discrepancy widened approximately three\u2010fold, with opposite directional changes in 28 patients. The pre\u2010treatment serum creatinine\/cystatin C ratio predicted the on\u2010treatment discrepancy, and\n                    <jats:italic>SLC47A1<\/jats:italic>\n                    rs2289669 GG was associated with a greater rise, consistent with a MATE1\u2010mediated mechanism. Because a fixed cross\u2010sectional threshold does not separate treatment\u2010associated discrepancy from pre\u2010existing discrepancy, a pre\u2010treatment cystatin C measurement is needed to interpret serum creatinine elevation during abemaciclib therapy.\n                  <\/jats:p>","DOI":"10.1002\/cpt.70490","type":"journal-article","created":{"date-parts":[[2026,9,23]],"date-time":"2026-09-23T03:45:38Z","timestamp":1790135138000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Creatinine\u2013Cystatin C Discrepancy and Renal Transporter Polymorphisms in Japanese Patients with Breast Cancer Receiving Abemaciclib"],"prefix":"10.1002","author":[{"ORCID":"https:\/\/orcid.org\/0009-0001-1396-4007","authenticated-orcid":false,"given":"Hiroaki","family":"Watanabe","sequence":"first","affiliation":[{"name":"Department of Pharmacy Shinshu University Hospital  Matsumoto Nagano Japan"},{"name":"Department of Clinical Pharmacy and Healthcare Sciences, Faculty of Pharmacy, Institute of Medical, Pharmaceutical and Health Sciences Kanazawa University  Kanazawa Ishikawa Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8027-3508","authenticated-orcid":false,"given":"Keita","family":"Hirai","sequence":"additional","affiliation":[{"name":"Department of Pharmacy Shinshu University Hospital  Matsumoto Nagano Japan"},{"name":"Department of Clinical Pharmacology and Therapeutics Shinshu University Graduate School of Medicine  Matsumoto Nagano Japan"},{"name":"School of Pharmaceutical Sciences Wakayama Medical University  Wakayama Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Takaaki","family":"Oba","sequence":"additional","affiliation":[{"name":"Division of Breast and Endocrine Surgery, Department of Surgery Shinshu University School of Medicine  Matsumoto Nagano Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mayu","family":"Ono","sequence":"additional","affiliation":[{"name":"Division of Breast and Endocrine Surgery, Department of Surgery Shinshu University School of Medicine  Matsumoto Nagano Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ken\u2010ichi","family":"Ito","sequence":"additional","affiliation":[{"name":"Division of Breast and Endocrine Surgery, Department of Surgery Shinshu University School of Medicine  Matsumoto Nagano Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7447-3789","authenticated-orcid":false,"given":"Takafumi","family":"Naito","sequence":"additional","affiliation":[{"name":"Department of Pharmacy Shinshu University Hospital  Matsumoto Nagano Japan"},{"name":"Department of Clinical Pharmacology and Therapeutics Shinshu University Graduate School of Medicine  Matsumoto Nagano Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,9,22]]},"reference":[{"key":"e_1_2_12_1_1","doi-asserted-by":"crossref","first-page":"718","DOI":"10.1016\/j.annonc.2024.04.013","article-title":"Abemaciclib plus a nonsteroidal aromatase inhibitor as initial therapy for HR+, HER2\u2010 advanced breast cancer: final overall survival results of MONARCH 3","volume":"35","author":"Goetz M.P.","year":"2024","journal-title":"Ann. 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Kidney J."},{"key":"e_1_2_12_12_1","doi-asserted-by":"crossref","DOI":"10.3389\/fneph.2024.1389562","article-title":"Case report: a case of pseudo\u2010acute kidney injury due to cyclin\u2010dependent kinase inhibitor","volume":"4","author":"Errabelli P.","year":"2024","journal-title":"Front. Nephrol."},{"key":"e_1_2_12_13_1","doi-asserted-by":"crossref","first-page":"1807","DOI":"10.34067\/KID.0003202022","article-title":"Advantages, limitations, and clinical considerations in using cystatin C to estimate GFR","volume":"3","author":"Chen D.C.","year":"2022","journal-title":"Kidney360"},{"key":"e_1_2_12_14_1","doi-asserted-by":"crossref","first-page":"525","DOI":"10.1038\/s41416-025-02951-4","article-title":"Pseudo acute kidney injury in patients receiving CDK4\/6 inhibitors","volume":"132","author":"Buijs S.M.","year":"2025","journal-title":"Br. J. 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