A Phase 2 Trial of Ribociclib (LEE011) and Letrozole in ER Positive Relapsed Ovarian Cancer, Fallopian Tube Cancer, Primary Peritoneal Carcinomas, and Endometrial Cancers.

Trial ID # NCT02657928
Phase II
Drug Class Hormonal Therapy: Aromatase
Drug Name Letrozole
Alternate Drug Names Femara
Drugs in Trial Letrozole, Ribociclib
Eligible Participant

Recurrent ER+ ovarian cancer

Patients Enrolled

20, median 3 prior therapies (0-6); 17 HGS, 3 HGS; 7-Pt-S, 12 Pt-R

Therapy Setting


Study Design

Open-Label, Non-randomized


ORR, DCR, PFS, OS, evaluated per RECIST




ORR: 15% (3PR - 3 LGS)
ORR (HGS): 0%
PFS ≥ 23 weeks: 25% (3PR, 2SD) - 3/3 LGS still on treatment for 28+, 24+ and 19+ months
PFS ≥ 23 weeks (HGS): 12% (2SD)
PFS (12 weeks): 50%
PFS: 2.8 months
OS: 18.9 months

Clinically Significant Adverse Events

Serious AE:
Grade 3-4 AE: Leukopenia (17.5%), neutropenia (15%), lymphopenia (10%)


Letrozole+ribociclib is active in ER+ ovarian cancer with 25% achieving PFS for 23 weeks or longer, but greatest benefit is seen in low grade serous (LGS) ovarian cancer


Colon-Otero G et al. Results of a phase 2 trial of ribociclib and letrozole in patients with either relapsed estrogen receptor (ER)-positive ovarian cancers or relapsed ER-positive endometrial cancers. J Clin Oncol (2019) 37 (suppl; abstr 5510)

Colon-Otero G et al. Slide from presentation

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