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It is essential to evaluate the efficacy and safety profiles of CDK4\/6i in Chinese patients with HR+\/HER2- ABC, in order to provide a theoretical foundation for developing precision-based therapeutic strategies.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Clinical data of patients with ABC treated with CDK4\/6i combined with ET between April 2021 and April 2024 at the Department of Breast Oncology, Sichuan Cancer Hospital, were retrospectively collected. Clinicopathological characteristics and prognostic outcomes were analyzed to evaluate the efficacy and safety of CDK4\/6i-based regimens, and then we explored factors associated with progression-free survival (PFS). The secondary endpoints incorporate overall survival (OS), objective response rate (ORR) and clinical benefit rate (CBR).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>A total of 124 patients were enrolled, with a median follow-up period of 23.0 months. The median PFS (mPFS) was 20.0 months, while the median OS (mOS) was not reached. Patients without measurable target lesions were excluded, and a total of 90 patients were included for further analysis. The ORR was 46.7% (42\/90), and the CBR was 53.3% (48\/90). Cox multivariate regression analysis identified Ki-67&lt;20%, Age-adjusted Charlson Comorbidity Index (aCCI)&lt;10, line of CDK4\/6i\u2009\u2264\u20092, and sensitivity or acquired resistance to ET as independent predictors of PFS. Leukopenia (83.1%) was the most common adverse event (AE), with 75.8% of these cases classified as grade 1\u20132.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>This real-world (RWD) study in China has further confirmed the efficacy and safety in HR+\/HER2- ABC. These findings provide further evidence for clinically identifying optimal patient population likely to derive superior benefits from CDK4\/6i combination regimens.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1186\/s12957-026-04486-1","type":"journal-article","created":{"date-parts":[[2026,7,9]],"date-time":"2026-07-09T13:43:13Z","timestamp":1783604593000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["CDK4\/6 inhibitor combined with endocrine therapy: a real-world evaluation of efficacy and safety in HR+\/HER2- advanced breast cancer"],"prefix":"10.1186","volume":"24","author":[{"given":"Rui","family":"Wang","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuying","family":"Wang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yaling","family":"Zeng","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xihui","family":"Tu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Di","family":"Lu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Purong","family":"Zhang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2026,7,9]]},"reference":[{"issue":"3","key":"4486_CR1","doi-asserted-by":"publisher","first-page":"463","DOI":"10.1007\/s10549-013-2647-2","volume":"140","author":"MJ Engstr\u00f8m","year":"2013","unstructured":"Engstr\u00f8m MJ, Opdahl S, Hagen AI, et al. 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