Abstract
Cyclin-dependent kinase 4 and 6 inhibitors (CDK4/6i) in combination with endocrine therapy improve the outcomes of patients with hormone-receptor (HR)-positive, HER2-negative advanced breast cancer and can be used early as first-line treatment or deferred to second-line treatment1-7. Randomized data comparing the use of CDK4/6i in the first- and second-line setting are lacking. The phase 3 SONIA trial (NCT03425838) randomized 1,050 patients who had not received previous therapy for advanced breast cancer to receive CDK4/6i in the first- or second-line setting8. All of the patients received the same endocrine therapy, consisting of an aromatase inhibitor for first-line treatment and fulvestrant for second-line treatment. The primary end point was defined as the time from randomization to disease progression after second-line treatment (progression-free survival 2 (PFS2)). We observed no statistically significant benefit for the use of CDK4/6i as a first-line compared with second-line treatment (median, 31.0 versus 26.8 months, respectively; hazard ratio = 0.87; 95% confidence interval = 0.74-1.03; P = 0.10). The health-related quality of life was similar in both groups. First-line CDK4/6i use was associated with a longer CDK4/6i treatment duration compared with second-line use (median CDK4/6i treatment duration of 24.6 versus 8.1 months, respectively) and more grade ≥3 adverse events (2,763 versus 1,591, respectively). These data challenge the need for first-line use of a CDK4/6i in all patients.
© 2024. The Author(s), under exclusive licence to Springer Nature Limited.
Publication types
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Randomized Controlled Trial
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Clinical Trial, Phase III
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Comparative Study
MeSH terms
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Aged
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Antineoplastic Agents* / administration & dosage
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Antineoplastic Agents* / pharmacology
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Antineoplastic Agents* / therapeutic use
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Antineoplastic Agents, Hormonal / administration & dosage
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Antineoplastic Agents, Hormonal / pharmacology
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Antineoplastic Agents, Hormonal / therapeutic use
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Antineoplastic Combined Chemotherapy Protocols* / therapeutic use
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Aromatase Inhibitors / administration & dosage
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Aromatase Inhibitors / pharmacology
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Aromatase Inhibitors / therapeutic use
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Breast Neoplasms* / classification
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Breast Neoplasms* / drug therapy
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Breast Neoplasms* / metabolism
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Breast Neoplasms* / pathology
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Cyclin-Dependent Kinase 4* / antagonists & inhibitors
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Cyclin-Dependent Kinase 4* / metabolism
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Cyclin-Dependent Kinase 6* / antagonists & inhibitors
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Cyclin-Dependent Kinase 6* / metabolism
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Disease Progression
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Estrogen Receptor Antagonists / administration & dosage
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Estrogen Receptor Antagonists / pharmacology
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Estrogen Receptor Antagonists / therapeutic use
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Female
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Fulvestrant / administration & dosage
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Fulvestrant / therapeutic use
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Humans
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Middle Aged
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Neoplasm Staging
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Progression-Free Survival
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Protein Kinase Inhibitors* / administration & dosage
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Protein Kinase Inhibitors* / pharmacology
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Protein Kinase Inhibitors* / therapeutic use
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Quality of Life
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Time-to-Treatment*
Substances
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Antineoplastic Agents
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Antineoplastic Agents, Hormonal
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Aromatase Inhibitors
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CDK4 protein, human
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CDK6 protein, human
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Cyclin-Dependent Kinase 4
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Cyclin-Dependent Kinase 6
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Estrogen Receptor Antagonists
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Fulvestrant
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Protein Kinase Inhibitors