Ribociclib (RIB) + fulvestrant (FUL) in postmenopausal women with hormone receptor-positive (HR+), HER2-negative (HER2-) advanced breast cancer (ABC): Results from MONALEESA-3
20 September 2018 (online)
MONALEESA-3 (NCT02422615) is a Phase 3 study of RIB + FUL in pts with HR+, HER2– ABC who received no or up to 1 line of prior endocrine therapy (ET) for ABC.
Postmenopausal women with HR+, HER2– ABC (N = 726) were randomized 2:1 to RIB (600 mg/day; 3-weeks-on/1-week-off) + FUL (500 mg) or placebo (PBO) + FUL. Primary objective: investigator-assessed PFS. Secondary objectives included overall survival, overall response rate (ORR), clinical benefit rate (CBR), and safety.
Median duration from randomization to data cut-off: 20.4 months. The primary objective was met: PFS was significantly improved in the RIB arm vs. the PBO arm (hazard ratio: 0.593; 95% confidence interval [CI]: 0.480 – 0.732; p = 4.10 × 10-7). Consistent PFS benefit was observed in pts with no (hazard ratio: 0.577; 95% CI: 0.415 – 0.802) and up to 1 line of prior ET for ABC (hazard ratio: 0.565; 95% CI: 0.428 – 0.744). In pts with measurable disease at baseline, ORR was 41% vs. 29% (RIB vs. PBO arm; p = 0.003); CBR was 69% vs. 60% (p = 0.015). In the RIB vs. PBO arms, Grade (G) 3/4 neutropenia occurred in 47%/7% vs. 0%/0% of pts, G3/4 increased ALT 7%/2% vs. < 1%/0%, and G3/4 increased AST in 5%/1% vs. 1%/0%.
RIB + FUL vs. PBO + FUL significantly prolonged PFS and demonstrated a manageable safety profile in postmenopausal pts with HR+, HER2- ABC who received no or up to 1 line of prior ET for advanced disease. RIB + FUL may, therefore, be a treatment option for this pt population.