Tolerability and Efficacy of Palbociclib and Ribociclib in Breast Cancer in Hong Kong: A Single-Centre Study

This is the authors' abstract. We don't add key points for this paper.

This study aimed to analyse the safety, tolerability, and other potential factors affecting the treatment outcome of advanced breast cancer (including inoperable stage III or stage IV, as per the eighth edition of the American Joint Committee on Cancer staging manual) treated with palbociclib or ribociclib at a single institution in Hong Kong. Methods: The medical records of all breast cancer patients receiving palbociclib or ribociclib at a hospital in Hong Kong during the period of July 2016 to February 2022 were reviewed. Data regarding baseline demographics, treatment-related adverse events, need for dose reduction, and disease progression were collected. Results: A total of 211 patients were included in the study, where 88.6% received palbociclib and 11.4% received ribociclib. Among the patients started on full doses (91.4% for palbociclib and 91.7% for ribociclib), 48.5% and 54.5% required dose reduction, respectively, most often due to neutropenia. No statistically significant factor could be identified for predicting the severity of neutropenia in this cohort. In patients on first-line treatment, dose reduction, treatment delay, high levels of oestrogen receptor and progesterone receptor were associated with longer progression-free survival, with respective p values of < 0.001, 0.010, 0.002, and 0.001. Conclusion: Palbociclib and ribociclib were safe and well-tolerated in a predominantly Asian population in real-life clinical practice, with comparable treatment outcomes to those quoted in international clinical trials. Dose reduction did not compromise the treatment efficacy.