ROLE OF CDK4/6 INHIBITORS IN METASTATIC HORMON POSITIVE HER2 NEGATIVE BREAST CANCER TREATMENT
Marija Ban, Ante Strikić, Branka Petrić Miše, Eduard Vrdoljak
Implementation of CDK4/6 inhibitors in metastatic hormone receptor positive, HER2 negative breast cancer treatment significantly improves progression free survival. CDK4/6 inhibitors are characterized by favorable toxicity profile. CDK4/6 inhibitor administration delays and/or overcomes endocrine therapy resistance in metastatic breast cancer. CDK4/6 inhibitors were tested in both first line treatment in combination with aromatase inhibitors, and in second line treatment in combination with fulvestrant. Progression free survival longer than 20 months in the first and longer than 10 months in the second treatment line has been achieved. Progression free survival prolongation may delay chemotherapy administration and consequently enable longer period with maintained quality of life. CDK4/6 inhibitors in combination with endocrine therapy represent a new valuable treatment option for metastatic hormone receptor positive HER2 negative breast cancer. However , many questions such as optimal patient selection as well as positioning of the CDK4/6 inhibitors and other endocrine therapy options during the course of metastatic disease treatment, remain unanswered. Furthermore, availability and cost of CDK4/6 inhibitors are also important issues.