MONALEESA-3: ribociclib linked to longer OS in HR+ HER2- advanced breast cancer

  • Slamon DJ & al.
  • N Engl J Med
  • 11 Dec 2019

  • curated by Miriam Davis, PhD
  • Univadis Clinical Summaries
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Takeaway

  • The MONALEESA-3 randomized controlled trial (RCT) showed that ribociclib plus fulvestrant was tied to an OS advantage over fulvestrant alone in postmenopausal patients with hormone receptor (HR)-positive, HER2-negative advanced breast cancer.

Why this matters

  • This is the second interim analysis of OS.
  • Previous results of this same trial showed that ribociclib+fulvestrant had a PFS advantage over fulvestrant alone.

Study design

  • International, placebo-controlled, phase 3 RCT of ribociclib+fulvestrant vs placebo+fulvestrant as first-line or second-line therapy (N=726) in patients with HR+/HER2 advanced breast cancer (metastatic disease or locoregional recurrent disease not amenable to curative treatments).
  • Funding: Novartis.

Key results

  • Median follow-up, 39.4 months.
  • Estimated OS at 42 months:
    • 57.8% in the ribociclib group (95% CI, 52.0%-63.2%) vs
    • 45.9% (95% CI, 36.9%-54.5%) in the placebo group; and
    • 28% difference in the relative risk for death: HR, 0.72 (P=.00455).
  • Subgroup analysis of first-line and second-line treatments showed similar results.
  • A descriptive analysis of median PFS showed an advantage for the ribociclib group receiving first-line therapy (33.6 [95% CI, 27.1-41.3] vs 19.2 [95% CI, 14.9-23.6] months).

Limitations

  • Limited to specific patient population included in the trial.