Phase 2 trial of everolimus and letrozole in relapsed estrogen receptor-positive high-grade ovarian cancers

Gynecol Oncol. 2017 Jul;146(1):64-68. doi: 10.1016/j.ygyno.2017.04.020. Epub 2017 Apr 28.


Objectives: We report the results of a phase 2 clinical trial of the combination of everolimus and letrozole in patients with relapsed estrogen receptor-positive high-grade ovarian cancer. The trial's primary endpoint was the proportion of patients alive and progression-free after 12weeks of therapy with the combination of everolimus and letrozole. A 12-week PFS of 45% or greater was considered a positive result. The feasibility of generating patient-derived xenograft (PDX) models from biopsy specimens was also evaluated.

Methods: Eligibility criteria included relapsed estrogen receptor-positive ovarian, fallopian tube or primary peritoneal carcinomas with measurable disease, not previously treated with everolimus or AIs. Both platinum-resistant and sensitive tumors were included. Xenografts were created from image-guided tumor biopsies at baseline. Patients received oral everolimus 10mg daily and letrozole 2.5mg daily.

Results: Twenty patients were enrolled, 19 were evaluable. Nine out of 19 were alive, progression-free, and still on treatment at the 12week evaluation time-point (12-week PFS of 47%) with a median PFS of 3.9months (95% CI: 2.8-11.0). The median overall survival was 13.0months. Twelve patients (63%) experienced at least one grade 3 or worse adverse events. PDX tumor engraftment was feasible in the majority of patients (9 out of 17, 52.9%).

Conclusions: The combination of everolimus and letrozole is associated with a promising 47% 12-week PFS rate in patients with ER-positive relapsed high-grade ovarian cancer with acceptable toxicity. PDX tumor models can be generated from biopsies of ovarian tumors.

Keywords: Aromatase inhibitors; Everolimus; Ovarian cancer; PDX models.

Publication types

  • Clinical Trial, Phase II
  • Multicenter Study

MeSH terms

  • Administration, Oral
  • Aged
  • Animals
  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use*
  • Aromatase Inhibitors / administration & dosage
  • Disease-Free Survival
  • Everolimus / administration & dosage
  • Female
  • Humans
  • Letrozole
  • Mice
  • Mice, SCID
  • Middle Aged
  • Neoplasm Grading
  • Nitriles / administration & dosage
  • Ovarian Neoplasms / drug therapy*
  • Ovarian Neoplasms / metabolism*
  • Ovarian Neoplasms / pathology
  • Receptors, Estrogen / biosynthesis*
  • Triazoles / administration & dosage
  • Xenograft Model Antitumor Assays


  • Aromatase Inhibitors
  • Nitriles
  • Receptors, Estrogen
  • Triazoles
  • Letrozole
  • Everolimus