Real-World Survival Data Of Palbociclib In Advanced And Metastatic Breast Cancer: A Multicenter Experience In Lebanon.

e13054 Background: Approximately 70% of all breast cancer cases are hormone receptor (HR) positive. One of the most important treatment strategies for HR positive, human epidermal growth factor receptor 2 (HER2) negative subtype was endocrine treatment monotherapy by targeting estrogen receptor or aromatization and thus reducing estrogen level. However, resistance to this treatment and disease progression is universal. In the past few years, palbociclib, an oral inhibitor of cyclin dependent kinase 4 and 6 have been approved by the FDA, as a new standard of care in the metastatic or locally advanced setting either as front line therapy or after progression. The aim of our study is to describe the real world experience with palbociclib. Methods: Eligible patients had histologically confirmed metastatic breast cancer estrogen and progesterone receptors positive and HER2 receptor negative. Palbociclib was given 125 mg orally for 21 consecutive days of a 28 day cycle. Patients were followed over one year. Primary objective was progression free survival (PFS). Tumor response and treatment tolerability were defined as secondary objectives. Results: From 2002 to 2018, we identified a total of 44 breast cancer patients. All patients were females. The median age at diagnosis was 57 years. Among all the patients, 33.3% had visceral metastasis, 35.9% had non visceral metastasis and 30.8% had the two types of metastasis. 64.1% were de novo metastatic and 35.9% were not de novo metastatic. 82.5% had less than 3 sites of metastasis. 47% of the study patients had received both chemotherapy and endocrine therapy during treatment course, and 13 % had only received prior adjuvant endocrine therapy. 28.26% took only prior systemic therapy for breast cancer. By the cutoff date for the final analysis (1/11/2018), a total of 8 events of disease progression occurred, no death events happened. The median progression free survival was 262.6 months for palbociclib combined with letrozole as first line. Conclusions: no data was published before on palbociclib in Lebanon. We are the first to describe these characteristics. Our result (PFS 26 2.6 months) is in conformity with the PFS obtain with PALOMA-2 (24 months).