Overall Survival of CDK4/6-Inhibitor-Based Treatments in Clinically Relevant Subgroups of Metastatic Breast Cancer: Systematic Review and Meta-Analysis

Francesco Schettini, Fabiola Giudici, Mario Giuliano, Massimo Cristofanilli, Grazia Arpino, Lucia Del Mastro, Fabio Puglisi, Sabino De Placido, Ida Paris, Pietro De Placido, Sergio Venturini, Michelino De Laurentis, Pier Franco Conte, Dejan Juric, Antonio Llombart-Cussac, Lajos Pusztai, Aleix Prat, Guy Jerusalem, Angelo Di Leo, Daniele Generali

Research output: Contribution to journalArticlepeer-review


BACKGROUND: Cyclin-dependent kinases 4 and 6 (CDK4/6) inhibitors + endocrine therapy (ET) prolonged progression-free survival as first- or second-line therapy for hormone receptor-positive (HR+)/HER2-negative metastatic breast cancer prognosis. Given the recent publication of overall survival (OS) data for the 3 CDK4/6-inhibitors, we performed a meta-analysis to identify a more precise and reliable benefit from such treatments in specific clinical subgroups. METHODS: We conducted a systematic literature search to select all available phase II or III randomized clinical trials of CDK4/6-inhibitors + ET reporting OS data in first- or second-line therapy of HR+/HER2-negative pre- or postmenopausal metastatic breast cancer. A random effect model was applied for the analyses. Heterogeneity was assessed with I2statistic. Subgroup analysis was performed to explore the effect of study-level factors. The project was registered in the Open Science Framework database (doi: 10.17605/OSF.IO/TNZQP). RESULTS: Six studies were included in our analyses (3421 patients). A clear OS benefit was observed in patients without (hazard ratio [HR] = 0.68, 95% confidence interval [CI] = 0.54 to 0.85, I2 = 0.0%) and with visceral involvement (HR = 0.76, 95% CI = 0.65 to 0.89, I2 = 0.0%), with at least 3 metastatic sites (HR = 0.75, 95% CI = 0.60 to 0.94, I2 = 11.6%), in an endocrine-resistant (HR = 0.79, 95% CI = 0.67 to 0.93, I2 = 0.0%) and sensitive subset (HR = 0.73, 95% CI = 0.61 to 0.88, I2 = 0.0%), for younger than 65 years (HR = 0.80, 95% CI = 0.67 to 0.95, I2 = 0.0%) and 65 years or older (HR = 0.71, 95% CI = 0.53 to 0.95, I2 = 44.4%), in postmenopausal (HR = 0.76, 95% CI = 0.67 to 0.86, I2 = 0.0%) and pre- or perimenopausal setting (HR = 0.76, 95% CI = 0.60 to 0.96, I2 = 0.0%) as well as in chemotherapy-naïve patients (HR = 0.72, 95% CI = 0.55 to 0.93, I2 = 0.0%). CONCLUSIONS: CDK4/6-inhibitors + ET combinations compared with ET alone improve OS independent of age, menopausal status, endocrine sensitiveness, and visceral involvement and should be preferred as upfront therapy instead of endocrine monotherapy.
Original languageEnglish
Pages (from-to)1089-1097
Number of pages9
JournalJ. Natl. Cancer Inst.
Issue number11
Publication statusPublished - Nov 1 2020


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