Palbociclib in real clinical practice: Results of a single-center observational study

Introduction. A breakthrough in the treatment of metastatic hormone-dependent (HR+) breast cancer was combination endocrine therapy with CDK4/6 inhibitors, which significantly prolonged the tumor response time to treatment and the median survival before progression. The effectiveness of combination endocrine therapy in real-life practice is of particular interest due to the wider population of patients with different somatic status and comorbidity, often not included in randomized trials. Aim. Analyze of palbociclib using for treating patients with HR+/HER2– advanced breast cancer (mBC) at the Republican Clinical Oncology Dispensary. Materials and methods. Data from 323 patients were analyzed. Our study examined the effectiveness of combination endocrine therapy with palbociclib in patients with metastatic HR+ HER2– breast cancer. Data on the clinicopathological characteristics of patients and disease progression during palbociclib administration were obtained by reviewing clinical data from patient records and radiological/pathological examination reports. Results. The median age of patients included in the study was 62 years. When assessing the antitumor response, a partial response was recorded in 54 patients (16.7%), stabilization in 212 patients (65.6%), and progression in 57 patients (17.8%). The median progression-free survival was 13 months. Grade 3 adverse events were noted in 23 patients: neutropenia in 21.7% of cases, hepatotoxicity in 47.8% of cases, cardiotoxicity in 17.4% of cases, and coagulopathy in 4.3%. No patient discontinued therapy due to adverse events. The best treatment results were achieved by patients who used the combination of palbociclib with an endocrine partner as the first line of treatment for advanced stage. Conclusion. This analysis of real-world data on the use of palbociclib in real-world clinical practice confirms the RCT data on the efficacy and safety of using CDK4/6 inhibitors for the treatment of patients with HR+ HER2- mBC.