Ribociclib-letrozole combo shows promise in ER+ ovarian, endometrial cancer

  • Colon-Otero G & al.
  • ESMO Open
  • 1 Oct 2020

  • curated by Deepa Koli
  • Univadis Clinical Summaries
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Takeaway

  • Ribociclib in combination with letrozole is associated with a 12-week PFS rate of:
    • 50% in patients with relapsed estrogen receptor-positive (ER+) ovarian cancer.
    • 55% in patients with relapsed ER+ endometrial cancer.
  • The PFS rate was higher in patients with ER+ recurrent low-grade serous ovarian cancer (LGSOC).

Why this matters

  • These findings, together with the low toxicity of the drug combination, make ribociclib and letrozole in patients with LGSOC a promising treatment, pending confirmatory randomized studies.

Study design

  • Phase 2 trial of 40 patients with measurable, relapsed ER+ ovarian cancer (n=20) or endometrial cancer (n=20) were treated with ribociclib plus letrozole.
  • Funding: Novartis; Mayo Clinic Cancer Center.

Key results

  • In patients with endometrial and ovarian cancer, respectively:
    • 12-week PFS rate was 55% and 50%.
    • Median PFS was 5.4 (95% CI, 3.1-11.8) and 2.8 (95% CI, 2.6-9.1) months.
    • 24-week PFS rate was 35% and 20%.
  • In subset analysis, PFS ≥24 weeks was reported in:
    • 100% of patients with LGSOC.
    • 45.5% of patients with grade 1 or 2 endometrioid endometrial cancer.
  • Patient-derived xenografts were successfully engrafted in 45% of patients.
  • Grade ≥3 adverse event rate was 60%.

Limitations

  • Small size.