1062 Background: Novel endocrine therapies (ETs) and targeted therapeutic regimens have been developed to dramatically improve the outcome of hormone receptor-positive (HR+), HER2-negative (HER2-) metastatic breast cancer (MBC). Since the absence of direct head-to-head comparisons for all regimens, decision-making guidelines are urgently needed for different endocrine sensitivity statuses. This study is to evaluate the efficacy of ET-based regimens in patients with HR+/HER2- MBC and to assess the heterogeneity among different compounds with a particular focus on their ability to improve survival outcomes. Methods: This network meta-analysis of phase II/III randomized controlled trials (RCTs) with at least one ET in HR+/HER2- MBC were enrolled. Based on the endocrine responses, participants were stratified into endocrine therapy sensitivity (ETS) and endocrine therapy resistance (ETR) groups. Primary endpoints, including progression-free survival (PFS) and overall survival (OS), were assessed by bayesian algorithms and primarily measured as surface under the cumulative ranking curve (SUCRA). Results: A total of 42 trials (22917 patients) were included. Regarding PFS, cyclin-dependent kinases 4/6 inhibitors (CDK4/6i) +fulvestrant 500mg (F500) was recommended for the ETS group (SUCRA = 76.92%), while chemotherapy was considered as the most effective option for the ETR group (SUCRA = 73.47%). For visceral metastases, CDK4/6i +aromatase inhibitors (AIs) could provide the extreme efficacy for the ETS group (SUCRA = 63.27%) while the CDK4/6i +F500 (SUCRA = 76.17%) as the prior regimen for the ETR group. For bone-only disease, CDK4/6i+F500 was preferred for both the ETS (SUCRA = 67.04%) and the ETR (SUCRA = 70.24%) group. Concerning OS, CDK4/6i+tamoxifen was estimated as the first-rank regimen for the ETS subgroup (SUCRA = 67.04%) and chemotherapy for the ETR subgroup (SUCRA = 60.02%). Regarding resistance category, abemaciclib +F500 was likely the best option with PFS, for both primary (SUCRA = 69.19%) and secondary ETR (SUCRA = 69.09%) settings, as well as primary ETR associated with OS improvement (SUCRA = 67.67%). Pictilisib +F500 could be the optimal treatment with OS for secondary ETR (SUCRA = 60.50%)group. Conclusions: The results showed that CDK4/6i + F500 was probably the most promising option in ETS, visceral ETR and bone-only disease settings in terms of PFS. OS subgroup analysis showed that different endocrine sensitivity statuses required various optimal treatment strategies.
280MO Progression free survival with endocrine therapy, before or after chemotherapy, in patients with hormone receptor-positive/HER2-negative metastatic breast cancer in a large multicenter national observational study
