Abstract 2269: Comparative effectiveness of everolimus + endocrine therapy vs endocrine monotherapy among postmenopausal women with HR+/HER2- advanced breast cancer: a multicountry retrospective chart review

Background: This study aims to compare patient characteristics and outcomes of everolimus (EVE) + endocrine therapy (ET) vs ET monotherapy among postmenopausal women with hormone receptor-positive (HR+) human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (aBC) across multiple countries. Methods: This retrospective chart review included postmenopausal patients with HR+/HER2- aBC who were previously treated with a nonsteroidal aromatase inhibitor (NSAI) and later received EVE + ET, ET monotherapy, or chemotherapy (the index treatment) from 17 sites in 6 countries (Canada, the Netherlands, France, Italy, Russia, and Argentina). This is a subset analysis comparing patients who received EVE + ET vs ET monotherapy. Stratified sampling by index treatment and line of therapy was used to ensure the sample groups included different treatments and lines of therapy. Patient characteristics were compared using Wilcoxon rank-sum tests for continuous variables and Fisher exact tests for categorical variables. Progression-free survival (PFS) was estimated using Kaplan-Meier analysis and was compared between the 2 groups using Cox proportional hazards models adjusting for age, country, line of therapy, metastatic sites, symptoms, comorbidities, prior chemotherapy, recurrent vs de novo cancer, and time from the last adjuvant ET to aBC diagnosis. Results: A total of 119 patients in the EVE + ET group (77 in 1st/2nd, and 42 in 3rd/4th lines) and 102 patients in the ET monotherapy group (76 in 1st /2nd, and 26 in 3rd/4th lines) were included in the study. All but 2 patients in the EVE + ET group received EVE + exemestane; ET monotherapy included fulvestrant (46.1%), exemestane (21.6%), NSAIs (16.7%), and tamoxifen (14.7%). Patients in the EVE + ET group were numerically younger (median 63.0 vs 66.0 years; P = .10); appeared to have fewer comorbidities, particularly hypertension (11.8% vs 35.3%; P number of metastatic sites (median 2.0 vs 1.0; P = .14); had a lower proportion of bone/joint symptoms (30.3% vs 42.2%; P = .07); and had a shorter time from initiation of the last adjuvant ET to aBC diagnosis (median 43.1 vs 55.6 months; P = .05). In the unadjusted analysis, patients in the EVE + ET group had similar PFS as those in the ET monotherapy group (median 9.1 vs 9.2 months; unadjusted HR = 0.98; P = .90), but after adjustment for baseline characteristics, the hazard of progression or death of any cause was lower (adjusted HR = 0.67; P = .05). Conclusions: Patients who received EVE + ET tended to be younger with fewer comorbidities yet have disease with faster progression and a higher burden of metastases. After adjusting for these characteristics, EVE + ET was associated with longer PFS compared with ET monotherapy. Citation Format: Fernando Petracci, Jose Zarba, Andrea Michelotti, Lorenzo Livi, Cristian Villanueva, Roberto Bordonaro, Viktor Sherstnev, Ruben Kowalyszyn, Nina Marinsek, Zhou Zhou, Alexander Macalalad, Valerie Koo, Erich Trieschman, Jipan Xie, James Signorovitch, Barbara Ratto, Keiko Higuchi, Mahasti Saghatchian. Comparative effectiveness of everolimus + endocrine therapy vs endocrine monotherapy among postmenopausal women with HR+/HER2- advanced breast cancer: a multicountry retrospective chart review. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2269.