Efficacy and Safety of Ribociclib With Letrozole in US Patients Enrolled in the MONALEESA-2 Study.

Abstract

BACKGROUND:

In the Mammary Oncology Assessment of LEE011's (Ribociclib's) Efficacy and Safety (MONALEESA-2) study, combination treatment with the selective inhibitor of cyclin-dependent kinases 4/6 ribociclib with letrozole significantly improved progression-free survival (PFS) versus letrozole alone in postmenopausal women with hormone receptor-positive HR+/HER2- advanced breast cancer (ABC). Herein we present results from the subset of US patients enrolled in MONALEESA-2.

PATIENTS AND METHODS:

Postmenopausal women with HR+/HER2- ABC without previous treatment for advanced disease were randomized (1:1) to ribociclib 600 mg/d (3 weeks on/1 week off) with letrozole 2.5 mg/d (continuous) or placebo with letrozole. The primary end point was locally assessed PFS.

RESULTS:

Overall, 213 US patients were enrolled in MONALEESA-2 (ribociclib, n = 100; placebo, n = 113). Baseline characteristics were similar between treatment groups and consistent with the global population. With a median follow-up of 27 months, 38 (38%) and 29 (26%) patients in the ribociclib and placebo groups, respectively, had continued to receive treatment. Median PFS was 27.6 months with ribociclib and 15.0 months with placebo (hazard ratio, 0.53). The most common all-cause adverse events were neutropenia (ribociclib, 72.0% [n = 72]; placebo, 4.6% [n = 5]), nausea (ribociclib, 69.0% [n = 69]; placebo, 44.0% [n = 48]), and fatigue (ribociclib, 60.0% [n = 60]; placebo, 50.5% [n = 55]). Two patients (ribociclib, 2.0%; placebo, 0%) experienced febrile neutropenia.

CONCLUSION:

In the US subset of MONALEESA-2, ribociclib with letrozole showed superior efficacy versus letrozole alone. These findings are consistent with the global population and support first-line use of ribociclib with letrozole in patients with HR+/HER2- ABC.

• Authors: Denise A Yardley, Lowell Hart, Anne Favret, Sibel Blau, Sami Diab, Donald Richards, Joseph Sparano, J Thad Beck, Paul Richards, Patrick Ward, Bhuvaneswari Ramaswamy, Michaela Tsai, Kimberly Blackwell, Timothy Pluard, Sara M Tolaney, Francisco J Esteva, Cristina I Truica, Carlos Alemany, Gena Volas-Redd, Mikhail Shtivelband, Das Purkayastha, Anand A Dalal, Michelle Miller, Gabriel N Hortobagyi
• Journal: Clinical breast cancer (Clin Breast Cancer) Vol. 19 Issue 4 Pg. 268-277.e1 (08 2019) ISSN: 1938-0666 [Electronic] United States
• PMID: 31160171 (Publication Type: Clinical Trial, Phase III, Journal Article, Multicenter Study, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2019. Published by Elsevier Inc.

Chemical References

• Aminopyridines
• Purines
• Letrozole
• ribociclib

Topics

• Adult
• Aged
• Aged, 80 and over
• Aminopyridines (administration & dosage)
• Antineoplastic Combined Chemotherapy Protocols (therapeutic use)
• Breast Neoplasms (drug therapy, pathology)
• Double-Blind Method
• Female
• Follow-Up Studies
• Humans
• Letrozole (administration & dosage)
• Middle Aged
• Neoplasm Metastasis
• Patient Safety
• Prognosis
• Purines (administration & dosage)
• Survival Rate
• Young Adult