Evaluation of CDK4/6 inhibitors in first-line in symptomatic and asymptomatic patients with metastatic breast cancer.

BACKGROUND

This study aimed to compare the efficacy of CDK4/6 inhibitors plus endocrine therapy in two groups of patients with HR-positive/HER2-negative metastatic breast cancer: those with symptomatic, high tumor burden disease and those with asymptomatic disease.

DESIGN AND METHODS

This retrospective study included 193 patients who received either ribociclib or palbociclib in combination with first-line ET. Patients were divided into symptomatic and asymptomatic groups and compared regarding baseline characteristics and progression-free survivals (PFS).

RESULTS

Symptomatic patients had a significantly shorter mPFS than asymptomatic patients (22.7 months vs. 35.0 months,  = 0.009). Among symptomatic patients, those treated with ribociclib had a longer mPFS than those treated with palbociclib (28.26 months vs. 17.18 months,  = 0.021). Multivariate analysis identified the symptomatic disease and liver metastasis as independent predictors of shorter mPFS (HR; 1.835, 95% CI; 1.146-2.939 and HR; 2.433, 95% CI; 1.329-4.454, respectively).

CONCLUSION

Our analysis revealed that although symptomatic individuals who underwent CDK4/6 inhibitor plus ET experienced a significant reduction in mPFS durations compared to asymptomatic patients, the 22-month mPFS indicated that CDK4/6 inhibitor plus ET is an effective treatment option.