Background: Endocrine therapy (ET) is an established treatment for premenopausal women with hormone receptor–positive (HR+)/human epidermal growth factor receptor 2–negative (HER2−) advanced breast cancer (ABC). MONALEESA-7 (NCT02278120) was the first phase 3 randomized trial of a cyclin-dependent kinases 4 and 6 inhibitor (ribociclib) + ET in premenopausal women with HR+/HER2− ABC without prior ET for ABC.1
Objective: To review efficacy, safety, and health-related quality of life (HRQoL) data from MONALEESA-7.
Methods: MONALEESA-7 enrolled 672 pre/perimenopausal women with HR+/HER2− ABC with ≤1 line of chemotherapy and no prior ET for ABC.1 Patients received oral ribociclib 600 mg/d (3 weeks on/1 week off) or placebo plus goserelin (3.6 mg every 28 d) and either tamoxifen (20 mg/d) or a nonsteroidal aromatase inhibitor (NSAI; letrozole [2.5 mg/d] or anastrozole [1 mg/d]).1 End points included progression-free survival (PFS; primary), overall response rate (ORR), clinical benefit rate (CBR), baseline and serial HRQoL evaluated using the European Organisation for Research and Treatment of Cancer Quality of Life Core 30 Questionnaire (EORTC QLQ-C30), and safety.1,2
Results: Of 672 enrolled patients, 177 received tamoxifen (ribociclib vs placebo group: 87 vs 90) and 495 received NSAI (248 vs 247).1,2 Baseline characteristics were well balanced between groups.1 With 19.2 months’ median follow-up, PFS was improved in the ribociclib group vs the placebo group (median PFS, 23.8 vs 13.0 months; hazard ratio [HR] 0.553; 95% CI, 0.441-0.694; P = .0000000983).1 PFS benefit was consistent with either ET partner (tamoxifen: HR 0.585; 95% CI, 0.387-0.884; NSAI: HR 0.569; 95% CI, 0.436-0.743).2 In patients with measurable disease at baseline, ORR (ribociclib vs placebo group) was 51% vs 36% (P = .000317), and CBR was 80% vs 67% (P = .000340).1 HRQoL questionnaire adherence was >78%.2 On-treatment EORTC QLQ-C30 global health status/QoL score was maintained up to cycle (C) 17.2 From C 19 to C 31, a clinically meaningful improvement (>5 points) in global health status/QoL score was observed in the ribociclib group; scores numerically worsened in the placebo group. At C 3, EORTC QLQ-C30 mean pain score was reduced from baseline by 5.1 (ribociclib group) and 3.5 points (placebo group).3 Pain score reductions were maintained up to C 28 in the ribociclib group versus up to C 17 in the placebo group, with clinically meaningful reductions (>5 points) in the ribociclib group from C 3 to C 11 and from C 22 to C 28. The most frequent adverse events (ribociclib vs placebo group) were neutropenia (76% vs 8%), hot flashes (34% vs 34%), nausea (32% vs 20%), leukopenia (31% vs 6%), and arthralgia (30% vs 27%).1 Corrected QT interval (Fridericia’s formula; QTcF) >480 ms (ribociclib vs placebo group) occurred in 7% vs 1% of patients.4 QTcF increase >60 ms from baseline (ribociclib vs placebo group: tamoxifen, 16% vs 7%; NSAI, 7% vs 0%) and postbaseline QTcF >480 ms (tamoxifen, 11% vs 1%; NSAI, 5% vs 1%) were more common with tamoxifen. No QTcF prolongation event was associated with clinical symptoms.2,4
Conclusions: Ribociclib plus ET demonstrated significant treatment benefit, including prolonged PFS, HRQoL improvement, and manageable safety in premenopausal women with HR+/HER2− ABC.
Disclosures: Assistance with preparation of this abstract was provided under the direction of the author by MedThink SciCom with support from Novartis Pharmaceuticals Corporation. Ribociclib was discovered by Novartis Institutes for BioMedical Research in collaboration with Astex Pharmaceuticals.
References
- Tripathy D et al. SABCS 2017. Abstract GS2-05.
- Data on file. Novartis Pharmaceuticals Corp; 2018.
- Harbeck N, et al. EBCC 2018. Abstract LBA1.
- Tripathy D, et al. Lancet Oncol. 2018 [Epub ahead of print].
