{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T18:23:32Z","timestamp":1785435812337,"version":"3.56.0"},"reference-count":53,"publisher":"MDPI AG","issue":"13","license":[{"start":{"date-parts":[[2026,6,24]],"date-time":"2026-06-24T00:00:00Z","timestamp":1782259200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"University of Palermo, Italy"},{"id":[{"id":"https:\/\/ror.org\/04fz79c74","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Cancers"],"abstract":"<jats:p>Background\/Objectives: Advanced hormone receptor-positive (HR+), epidermal growth factor 2-negative (HER2\u2212) breast carcinoma (BC) patients receive frontline therapy with cyclin-dependent tyrosine kinase 4\/6 inhibitors + endocrine therapy (ET). At progression, the best management includes mutational analysis for ESR-1, allowing second-line therapy with elacestrant. The aim of this study was to evaluate the efficacy and safety of elacestrant in an Italian real-world setting. Methods: A multicenter, observational study with a mixed retrospective and prospective design was conducted in 13 medical oncology units across Italy. The study population included adult patients with HR+\/HER2\u2212 locally advanced or metastatic breast cancer with an activating ESR1 mutation documented by liquid biopsy and progressing after at least one line of endocrine therapy containing a CDK4\/6 inhibitor. Mutational analysis of plasma was performed using next-generation sequencing with a multigene panel that included ESR1, PIK3CA, AKT, and PTEN. The sample size was calculated according to the two-stage Simon design. Toxicity was classified according to CTCAE version 5.0 criteria. Survival analyses were conducted using the Kaplan\u2013Meier method. Results: At the time of analysis, 39 evaluable patients were enrolled, all female and Caucasian, with a median age of 67 years (range 41\u201389). The efficacy analysis documented an overall ORR of 28% and a disease control rate of 56%. The median duration of response was 6+ months (95% CL: 3.5\u201310.6 m). Median overall survival was not reached with a median follow-up of 10 months. The toxicity profile was overall favorable: grade \u22652 asthenia was the most frequent adverse event (23%), followed by gastrointestinal toxicity, which was generally mild. No treatment-related toxicity was reported in 64% of patients. Dose reductions were necessary in 15% of cases, while permanent treatment discontinuation due to toxicity occurred in only 4%. Conclusions: The results of this Italian multicenter observational study confirm the efficacy and tolerability of elacestrant in HR+\/HER2\u2212 metastatic breast cancer with ESR1 mutation, in a real-world context consistent with the data from the pivotal EMERALD study and with real-world data present in the literature.<\/jats:p>","DOI":"10.3390\/cancers18132042","type":"journal-article","created":{"date-parts":[[2026,6,25]],"date-time":"2026-06-25T01:03:56Z","timestamp":1782349436000},"page":"2042","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["A Real-World Study on the Effectiveness and Safety of Elacestrant in Patients with ESR1-Mutated Metastatic Breast Cancer Progressing After CDK4\/6 Inhibitors and Endocrine Therapy"],"prefix":"10.3390","volume":"18","author":[{"given":"Martina","family":"Greco","sequence":"first","affiliation":[{"name":"Medical Oncology Unit and Breast Unit, Policlinico P. Giaccone, University of Palermo, 90100 Palermo, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8406-9416","authenticated-orcid":false,"given":"Vittorio","family":"Gebbia","sequence":"additional","affiliation":[{"name":"Medical Oncology, Department of Medicine and Surgery, Kore University of Enna, 94100 Enna, Italy"},{"name":"Medical Oncology Unit, CDC Torina, 90145 Palermo, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9529-2960","authenticated-orcid":false,"given":"Rossana","family":"Berardi","sequence":"additional","affiliation":[{"name":"Medical Oncology, Universit\u00e0 Politecnica delle Marche, AOU delle Marche, 60126 Ancona, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Antonella","family":"Usset","sequence":"additional","affiliation":[{"name":"Medical Oncology, Ospedale Civico ARNAS, 90127 Palermo, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7282-3597","authenticated-orcid":false,"given":"Giuseppina","family":"Ricciardi","sequence":"additional","affiliation":[{"name":"Medical Oncology, Ospedale Papardo, 98121 Messina, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2884-1632","authenticated-orcid":false,"given":"Nicla","family":"La Verde","sequence":"additional","affiliation":[{"name":"Medical Oncology Unit, Ospedale Sacco, 20157 Milano, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0001-6813-9426","authenticated-orcid":false,"given":"Maria Vita","family":"San\u00f2","sequence":"additional","affiliation":[{"name":"Medical Oncology, Humanitas Istituto Clinico Catanese, 95045 Catania, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Federica","family":"Martorana","sequence":"additional","affiliation":[{"name":"Medical Oncology, Humanitas Istituto Clinico Catanese, 95045 Catania, Italy"},{"name":"Department of Clinical and Experimental Medicine, University of Catania, 95123 Catania, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nicoletta","family":"Staropoli","sequence":"additional","affiliation":[{"name":"Medical Oncology, Magna Graecia University of Catanzaro, 88100 Catanzaro, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gianfranco","family":"Pernice","sequence":"additional","affiliation":[{"name":"Medical Oncology Unit, Ospedale Giglio, 90015\u00a0Cefal\u00f9,  Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gabriella","family":"Bini","sequence":"additional","affiliation":[{"name":"Medical Oncology Unit, Ospedale Villa Sofia-Cervello, 90146 Palermo, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Angela","family":"Prestifilippo","sequence":"additional","affiliation":[{"name":"Medical Oncology Unit, Istituto Mediterraneo di Oncologia, 95029 Viagrande,  Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5284-5281","authenticated-orcid":false,"given":"Francesco","family":"Giotta","sequence":"additional","affiliation":[{"name":"Medical Oncology Unit, Istituto Tumori Giovanni Paolo II, 70124 Bari, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Domenico","family":"Bilancia","sequence":"additional","affiliation":[{"name":"Medical Oncology Unit, Ospedale San Carlo, 85100 Potenza, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4396-3563","authenticated-orcid":false,"given":"Calogero","family":"Cipolla","sequence":"additional","affiliation":[{"name":"Breast Unit, Policlinico, Department of Biomedicine, Neuroscience and Advanced Diagnostics, University of Palermo, 90100 Palermo, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Martina","family":"De Luca","sequence":"additional","affiliation":[{"name":"Medical Oncology Unit and Breast Unit, Policlinico P. Giaccone, University of Palermo, 90100 Palermo, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maria Rosaria","family":"Valerio","sequence":"additional","affiliation":[{"name":"Medical Oncology Unit and Breast Unit, Policlinico P. Giaccone, University of Palermo, 90100 Palermo, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,24]]},"reference":[{"key":"ref_1","unstructured":"National Comprehensive Cancer Network (2026, May 01). NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines\u00ae). Breast Cancer Version 1. 2025. Available online: https:\/\/www.nccn.org."},{"key":"ref_2","unstructured":"Gennari, A., Curigliano, G., Trapani, D., Martins, B.D., Pentheroudakis, G., and Harbeck, N. (2026, May 11). ESMO Metastatic Breast Cancer Living Guideline v1. 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