Ribociclib + Letrozole: First-Line Standard

Source

Source: Hortobagyi GN, Stemmer SM, Burris HA, et al. Ribociclib as First-Line Therapy for HR-Positive, Advanced Breast Cancer. N Engl J Med. 2016;375:1738-48.

HR+/HER2- Advanced Breast Cancer Phase 3 RCT | Median Follow-up: 15.3 Months

Population

N = 668 Postmenopausal women.
Recurrent/metastatic. No prior systemic therapy for advanced disease.

Study Arms

Investigational (n=334)
Ribociclib (600mg) + Letrozole

Control (n=334)
Placebo + Letrozole

Hazard Ratio

0.56

44% Risk Reduction

(P<0.001)

Primary Endpoint: PFS

Ribociclib + Letrozole Not Reached (95% CI: 19.3–NR)

Placebo + Letrozole 14.7 Mo (Median)

Ribociclib group demonstrated a statistically significant improvement in progression-free survival compared to placebo.

Benefit vs. Risk Profile

Clinical Recommendation

Adopt Ribociclib + Letrozole as a preferred first-line treatment. The combination delivers practice-changing efficacy.

Safety Note: Rigorous monitoring required for Grade 3/4 neutropenia (59.3%) and QT prolongation.

AbbreviationsQuick

CDK4/6, cyclin-dependent kinases 4 and 6; CI, confidence interval; ECOG, Eastern Cooperative Oncology Group; ER, estrogen receptor; HER2, human epidermal growth factor receptor 2; HR, hormone receptor; NSAI, nonsteroidal aromatase inhibitor; PI3K, phosphatidylinositol 3-kinase; PR, progesterone receptor; QTcF, QT interval corrected for heart rate according to Fridericia’s formula; RECIST, Response Evaluation Criteria in Solid Tumors.

Bibliography2

Hortobagyi GN, Stemmer SM, Burris HA, et al. Ribociclib as First-Line Therapy for HR-Positive, Advanced Breast Cancer. N Engl J Med. 2016;375:1738-48. (DOI: 10.1056/NEJMoa1609709 | link)
ClinicalTrials.gov. NCT01958021.