Background: In the Phase III ML-3 (NCT02422615) and ML-7 (NCT02278120) trials, RIB + ET demonstrated a significant OS benefit (ML-3: HR, 0.72, P = 0.00455; ML-7: HR, 0.71, P = 0.00973) over placebo (PBO) + ET in pts with HR+/HER2- ABC (Im et al. N Engl J Med. 2019; Slamon et al. N Engl J Med. 2019). The presence of visceral mets generally portends a poor prognosis, which is especially poor in pts with liver mets (He et al. Ann Oncol. 2019). Here we report OS in pts with visceral mets with a focus on those with liver mets in ML-3 and ML-7. Methods: In ML-3, postmenopausal pts were randomized 2:1 to receive RIB + fulvestrant (FUL) or PBO + FUL as first- (1L) or second-line (2L) treatment. In ML-7, premenopausal pts were randomized 1:1 to receive RIB + ET or PBO + ET (this analysis included only pts who received an NSAI as ET partner to match approved indication). Results: Visceral mets were identified in 293 pts (60.5%) in the RIB arm and 147 (60.7%) in the PBO arm in ML-3 and 150 (44.8%) and 142 pts (42.1%), respectively, in ML-7. In ML-3, the median age of pts with visceral mets was 63 and 65 years in the RIB and PBO arms, and in ML-7 it was 42.5 and 45.0 years, respectively. In ML-3, 214 pts with visceral mets received 1L therapy (RIB, n = 137; PBO, n = 77), while 219 pts received 2L therapy or had early relapse (RIB, n = 151; PBO, n = 68). Lung and liver were the most common sites of visceral mets for pts in ML-3 (49.8% and 44.8%, respectively) and ML-7 (51.4% and 58.2%, respectively). OS HRs in pts with visceral mets were consistent with the benefit in the overall pt populations and suggested a particularly substantial OS benefit in pts with liver mets (HR for liver mets group in ML-3, 0.629 [95% CI, 0.421-0.942]; HR in ML-7, 0.531 [95% CI, 0.321-0.877]; Table). No new safety signals were observed. Conclusions: Approximately half of the pts in ML-3 and ML-7 had visceral mets. The OS data in these pts are consistent with the benefit observed with RIB in the overall populations of each trial. In pts with liver mets, a group with an especially poor prognosis, RIB + ET demonstrated a substantial OS benefit compared with PBO + ET. Clinical trial information: NCT02422615; NCT02278120.

NE, not evaluable.