Palbociclib plus endocrine therapy in HER2 negative, hormonal receptor-positive, advanced breast cancer: A real-world experience

Data from 423 human epidermal growth factor receptor 2-negative (HER2−), hormone receptor-positive (HR+) advanced breast cancer (aBC) patients treated with palbociclib and endocrine therapy (ET) were provided by 35 Italian cancer centers and analyzed for treatment outcomes. Overall, 158 patients were treated in first line and 265 in second/later lines. We observed 19 complete responses and 112 partial responses. The overall response rate (ORR) was 31% (95% confidence interval [CI], 26.6–35.4) and clinical benefit was 52.7% (95% CI, 48–57.5). ORR was negatively affected by prior exposure to everolimus/exemestane (p = 0.002) and favorably influenced by early line-treatment (p < 0.0001). At…