47MO Efficacy and quality of life (QOL) in premenopausal Asian patients (pts) with hormone receptor–positive (HR+), HER2-negative (HER2-) advanced breast cancer (ABC) treated in the MONALEESA (ML)-7 study

In the phase III ML-7 trial, ribociclib (RIB) + endocrine therapy (ET) prolonged progression-free survival (PFS) and overall survival (OS) vs placebo (PBO) + ET in premenopausal pts with HR+, HER2− ABC. The RIB benefit was observed irrespective of ET partner (nonsteroidal aromatase inhibitor [NSAI] or tamoxifen [TAM]). Here we report outcomes in Asian pts enrolled in the ML-7 trial receiving an NSAI + RIB or PBO. Pre/perimenopausal pts (≤ 1 line of prior chemotherapy; no prior ET for ABC) who received RIB or PBO + NSAI (letrozole or anastrozole) were included in this analysis. The primary end point was PFS, with a prespecified subset analysis in Asian pts. OS, overall response rate (ORR), clinical benefit rate (CBR), QOL, and safety were secondary end points. 166 pts (34% of the total NSAI cohort) were included (RIB, n=82; PBO, n=84); 31% of pts had de novo metastatic disease, and 4% and 66% had a DFI ≤ 12 mo and > 12 mo, respectively. As of 30 Nov 2018, 33 and 16 pts in the RIB and PBO arms, respectively, were still receiving treatment; the primary cause of discontinuation was disease progression (50% for RIB vs 70% for PBO). A consistent PFS and OS benefit with RIB vs PBO was observed in Asian pts vs the intention-to-treat population (Table). ORR and CBR favored RIB + NSAI vs PBO + NSAI in Asian pts with measurable disease at baseline. The EORTC QLQ-C30 global health score was generally maintained throughout RIB treatment. The only grade 3/4 adverse event occurring in > 20% of pts in either arm was neutropenia (78% for RIB vs 4% for PBO). These findings indicate that treatment with RIB + NSAI improved PFS nearly 3-fold and prolonged OS with a relative reduction in risk of death of 56% vs PBO + NSAI in Asian pts with HR+/HER2− ABC. Safety findings in Asian pts were consistent with the overall population, and QOL was maintained during RIB + NSAI treatment.Table: 47MOML-7 Asian subsetRIB + NSAI n = 82PBO + NSAI n = 84Age, median (range), yrs43 (27-58)45 (29-58)Weight, mean (SD), kg59.9 (12.1)55.8 (9.1)PFS events, n/N42/8260/84PFS, median (95% CI), mo30.4 (24.6-37.7)11.0 (7.4-14.7)HR (95% CI)0.47 (0.31-0.71)OS events, n/N15/8230/84OS, median (95% CI), moNE (NE-NE)NE (31.6-NE)HR (95% CI)0.44 (0.23-0.81)36-Mo OS, % (95% CI)78.9 (66.9-86.9)61.5 (49.0-71.8)42-Mo OS, % (95% CI)NE (NE-NE)50.7 (33.4-65.8)ORR, n (%)a95% CI43 (66.2)54.7-77.728 (36.8)26.0-47.7CBR, n (%)b95% CI56 (86.2)77.8-94.648 (63.2)52.3-74.0a ORR = CR+PR in pts with measurable disease (RIB, n = 65; PBO, n = 76) b CBR = CR+PR or SD or non-CR/non-PD ≥ 24 weeks in pts with measurable disease. Open table in a new tab