Abemaciclib for treating patients with HR+/HER2- metastatic breast cancer: a real-world study in France, Italy and Spain

<b>Aim:</b> This real-world study aimed to describe patient and clinical characteristics, treatment patterns and outcomes for patients with HR+/HER2- metastatic breast cancer receiving abemaciclib in France, Italy and Spain. <b>Materials &amp; methods:</b> A multicenter chart review was conducted for adult females with HR+/HER2- advanced/metastatic breast cancer who received abemaciclib in routine care. Real-world progression-free survival (rwPFS) was estimated via Kaplan-Meier curves. <b>Results:</b> This study included 151, 173 and 175 patients from France, Italy and Spain, respectively. Abemaciclib was mostly prescribed as first-line therapy concomitantly with hormone therapy. Median rwPFS was &gt;20 months and the 1-year rwPFS rate was &gt;70%. <b>Conclusion:</b> Effectiveness was similar across the three countries and aligns with pivotal studies. <b>Abemaciclib use in the clinic in France, Italy &amp; Spain</b> This study describes patients, the treatments they have received and the results of those treatments for patients with the most common type of advanced breast cancer. These patients were taking abemaciclib plus hormonal therapy in routine breast cancer care in France, Italy and Spain. The information used to conduct this study was taken from patients' medical charts. In this real-world study, abemaciclib was mostly used as the initial treatment for advanced breast cancer. Abemaciclib effectiveness was similar across the three countries confirming findings from previous studies. Our study supports the use of abemaciclib for patients with HR+/HER2- advanced breast cancer. Patients receiving abemaciclib in routine care in France, Italy and Spain were predominantly postmenopausal with a mean age of approximately 60 years. Breast cancer histological type at first diagnosis was predominantly nonspecific invasive carcinoma. Abemaciclib was mostly prescribed in the first-line setting in combination with aromatase inhibitors or fulverstrant. Overall, most patients who initiated abemaciclib received a starting dose of 150 mg twice a day. Range of discontinuation was between 45 and 55% across the three countries. Real-world tumor response and rwPFS support the real-world use of abemaciclib for the treatment of HR+/HER2- advanced/metastatic breast cancer. Median rwPFS was ≥20 months for patients who received abemaciclib as first and second therapy lines across the three countries. Median rwPFS was highest for patients who received abemaciclib in the first-line setting. Levels of hospitalization remained low, and relatively constant, in the period immediately before treatment initiation and in the period after. Our findings corroborate the effectiveness of real-world abemaciclib treatment for patients with advanced/metastatic breast cancer.