engleski

The first subsequent systemic treatment of metastatic hormone sensitive breast cancer after progression on CDK 4/6 inhibitors: real world data for UHC Zagreb

Introduction: CDK4/6 inhibitors in combination with endocrine therapy have been reimbursed by Croatian Health Insurance Fond in the first line of HR+/HER2– metastatic breast cancer since August 2018. As current experiences with CDK4/6 inhibitors as well as response to subsequent therapies are limited, there are no precise guidelines for post-progression therapy. The aim of this study was to analyse real-world data for the subsequent therapy options after progression on CDK 4/6 inhibitors in University Hospital Centre Zagreb and to compare them with the published data. Methods: We retrospectively analysed data from the hospital information system for 203 patients (200 female and 3 male patients) treated with a combination of endocrine therapy and CDK 4/6 inhibitor. Median age was 62 years (30–87), and median follow-up was 12 months (1– 32). 18 patients were treated with abemaciclib, 106 with palbociklib and 79 with ribociclib. Analysis of treatment options after progression was done on 71 patients who had disease progression by 15. 10. 2020., of whom 31 were treated by first and 40 on a subsequent line of therapy. Result: Of the 71 patients who had disease progression, 55 were switched to a new line of therapy. 39 (70, 91%) received chemotherapy, most often with capecitabine (15) and paclitaxel (13). Endocrine monotherapy was administered in 10 patients (18, 18%) – fulvestrant in 6, an aromatase inhibitor in 3 and tamoxifen in one patient. Targeted therapy was given to 6 patients (10, 91%), 2 of whom got alpelisib with fulvestrant and 4 changed disease biology – therefore atezolizumab for triple- negative and anti-HER2 therapy for HER2 positive disease was given. Conclusion: The choice of first post-progression therapy was predominately chemotherapy, primarily with capecitabine and paclitaxel. Targeted therapy is also a viable choice especially in patients who have a confirmed PIK3CA signal pathway mutation or a conversion to HER2 positive disease. In previous studies, chemotherapy was also the most common choice but more patients received endocrine therapy than in this study (30, 7% to 18, 18%). Since the identification of PIK3CA mutation status has only recently become available in Croatia, in the future alpelisib with fulvestrant is expected to become a reasonable choice for patients with PIK3CA signal pathway mutations.

therapy sequence ; HR+HER2 negative ; metastatic brest cancer

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