Ribociclib is a highly selective inhibitor of cyclin- -dependent kinase (CDK)4/6. The MONALEESA-2 study has shown that ribociclib in combination with letrozole reduced the risk of disease progression or death by 43% compared with letrozole alone.
Combined therapy resulted in attaining the median of progression-free survival (PFS) at 25.3 months compared with 16.0 months in patients treated with letrozole alone. Most common undesirable effect, including degree GREATER-THAN OR EQUAL TO 3, was neutropenia that was not, however, correlated with neutral neutropenia (1.5%) and could be well managed with delaying the dose or its reduction.
It is necessary to monitor the QTc interval in ECG and liver function test values on the beggining of therapy. Ribociclib in combination with hormonal therapy can provide substantial contribution in the form of delaying disease recurrence in patients with metastatic HR-positive and HER2-negative breast cancer.