Final results of the randomized phase 2 <scp>LEO</scp> trial and bone protective effects of everolimus for premenopausal hormone receptor?positive, <scp>HER2</scp> ?negative metastatic breast cancer

The phase 2 LEO study showed that everolimus (EVE) plus letrozole (LET) with ovarian suppression increased progression-free survival (PFS) in tamoxifen-exposed premenopausal women hormone receptor-positive, HER2-negative metastatic breast cancer visceral metastases. Here we report final outcomes from the study, and results of exploratory analyses bone turnover marker changes bone-specific progressive disease. Patients who were exposed to or progressed on tamoxifen as adjuvant/palliative treatments randomly assigned (2:1) EVE (leuprorelin + LET EVE, n = 92) LET, 45) arm. In a median 51-months follow-up, PFS was 17.5 13.8 months arms, respectively (P .245). arm baseline (median 16.4 vs 9.5 months, P .040) 17.1 10.9, .003) metastases had greater compared No differences overall (OS) observed OS, 48.3 50.8 .948). 1-year cumulative incidences disease progression 6.0% 23.4% (hazard ratio 0.26, < .001). Bone markers at 6 12 weeks after treatment decreased but stationary Skeletal-related events occurred 6.5% 11.1% patients respectively. prolonged offered bone-protective effects population. However, these clinical benefits did not translate into an OS benefit.