[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"health-studies-list:{\"conditionNormalized\":\"hrher2--abc-undergoing-1l-treatment-with-cdk46i-palbociclib-abemaciclib-or-ribociclib-and-ai-anastrozole-or-letrozole\",\"overallStatus\":[\"RECRUITING\",\"AVAILABLE\",\"NOT_YET_RECRUITING\"],\"orderBy\":\"LastUpdateSubmitDate:desc\",\"size\":25,\"offset\":0}":3,"health-study-condition:hrher2--abc-undergoing-1l-treatment-with-cdk46i-palbociclib-abemaciclib-or-ribociclib-and-ai-anastrozole-or-letrozole":26},{"pageToken":4,"total":5,"offset":6,"count":5,"results":7},null,1,0,[8],{"id":9,"slug":10,"hasResults":11,"nctId":12,"briefTitle":13,"officialTitle":13,"acronym":14,"eligibilityCriteria":15,"healthyVolunteers":11,"sex":16,"minAge":17,"maxAge":4,"enrollmentInfo":18,"targetDuration":4,"studyType":21,"phases":22,"briefSummary":24,"conditions":25,"keywords":4,"overallStatus":27,"whyStopped":4,"lastUpdateSubmitDate":28,"lastUpdatePostDateStruct":29,"startDateStruct":32,"completionDateStruct":34,"leadSponsor":36,"locationsCount":39},"100655859","esr1real-world-assessment-prevalence-study-100655859",false,"NCT07817212","ESR1Real World Assessment Prevalence Study","ESRA","Inclusion Criteria:\n\n1. Subject must be female or male and aged ≥ 18 years on the day of signing informed consent\n2. Patient has locally advanced or metastatic breast cancer not amenable to curative treatment\n3. Patient has HER2- breast cancer confirmed by local laboratory, defined as a negative in situ hybridization test or an IHC status of 0 or 1+. If IHC is 2+, a negative in situ hybridization (FISH, CISH, or SISH) test is required to confirm the HER2-negative status (based on the most recently analyzed tissue sample tested by a local laboratory)\n4. Histologically confirmed ER-positive and\u002F or PgR-positive breast cancer determined by core biopsy according to local in-house standard\n5. Patient has already initiated or is about to initiate first-line therapy with a CDK4\u002F6 inhibitor (any CDK4\u002F6i) in combination with an aromatase inhibitor (non-steroidal AI). Treatment must be intended as first-line systemic therapy for advanced or metastatic disease\n6. Information about prior oncological therapies against the HR+\u002FHER2- BC must be available\n7. Data about histo-pathological report must be available, including hormone receptor status, tumor histology, tumor grading and HER2 immunohistochemistry\n8. Inclusion in the study occurs as a single, one-time event for each patient, within one of the 9 defined cohorts\n\nExclusion Criteria:\n\n1. Patients with an interruption of ongoing first-line CDK4\u002F6i plus AI therapy exceeding 1 month for either CDK4\u002F6i or AI\n2. Patients receiving any other systemic anticancer therapy for HR+\u002FHER2- aBC, except for LHRH agonists, bisphosphonates, or denosumab\n3. Clinical evidence of progression at the timepoint of study inclusion\n4. Patients have already completed ≥ 1L of systemic therapy for aBC","ALL","18 Years",{"count":19,"type":20},1550,"ESTIMATED","INTERVENTIONAL",[23],"NA","Many patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+\u002FHER2-) advanced breast cancer in the first therapy line is endocrine sensitive. For these patients the established 1st line standard therapy is a combination of a CDK4\u002F6 inhibitor and an aromatase inhibitor. This combination therapy is usually given until clinical progression.\n\nRecent studies suggest that a detection of a somatic ESR1 mutation in the ctDNA can be clinically used to prompt an earlier change from the aromatase inhibitor to a selective estrogen receptor degrader.\n\nFor implementation in the clinical routine it is important to gain knowledge about the dynamics of ESR1 mutation in HR+\u002FHER2- advanced breast cancer patients during their first line therapy. At the beginning of the first line therapy about 5-8% of patients show an ESR1 mutation. An identification of patients with resistance to aromatase inhibitors at that timepoint might not be feasible and cost-efficient. At the timepoint of clinical progression up to 30-40% of patients will have acquired an ESR1 mutation. Knowledge about the mutation frequencies at different timepoints will be very helpful to direct testing strategies for implementing testing broadly in a population.\n\nThe aim of this study is to test ESR1 mutation frequencies in groups of patients (single time test per patient) with no clinical progression and different durations under first-line treatment with aromatase inhibitor and CDK4\u002F4 inhibitor.",[26],"HR+\u002FHER2- aBC Undergoing 1L Treatment With CDK4\u002F6i (Palbociclib, Abemaciclib or Ribociclib) and AI (Anastrozole or Letrozole)","NOT_YET_RECRUITING","2026-09-08",{"date":30,"type":31},"2026-09-14","ACTUAL",{"date":33,"type":20},"2026-10-01",{"date":35,"type":20},"2027-12-31",{"name":37,"class":38},"Institut fuer Frauengesundheit","OTHER",21]