Evaluation of Factors That Increase the Risk of Hepatotoxicity in Patients Using Palbociclib and Ribociclib

Aim: In patients with hormone receptor-positive and HER2-negative metastatic breast cancer, the use of CDK 4/6 inhibitors in combination with endocrine therapy have become a standard of care. Methods: This was a retrospective study involved patients over the age of 18 years, who had de novo metastatic or locally breast cancer progressed to the metastatic stage and were treated with ribociclib and/or palbociclib. Results: The mean age of a total of 73 patients included in the study was 57.0±10.3 years. Thirty-four (46.6%) patients were treated with palbociclib, 35 (47.9%) patients with ribociclib, 4 (5.5%) with palbociclib and ribociclib. Twenty-five (34.2%) of the patients developed any grade of hepatotoxicity, 12 (16.4%) of them was grade 2 hepatotoxicity. Of these patients, 11 (44%) received palbociclib, 13 (52%) received ribociclib, and 1 (4%) received palbociclib and ribociclib. In patients who were treated with palbociclib, 1 (2.9%) developed grade 3 hepatotoxicity and 1 (2.9%) developed grade 4 hepatotoxicity. Of those who received ribociclib, 3 (8.5%) developed grade 3 hepatotoxicity and 2 (5.7%) developed grade 4 hepatotoxicity. Conclusions: In conclusion, it can be stated that ribociclib is more toxic to the liver than palbociclib, since patients who received ribociclib and developed grade 3-4 hepatotoxicity had no disease that facilitates hepatotoxicity. We believe that more comprehensive studies are needed to determine the factors that facilitate hepatotoxicity such as liver metastasis and to select the drug accordingly will prevent patients from being devoid of this group of drugs and discontinuing their treatment due to toxicity.