An increase in the median progression-free survival when using cyclin-dependent kinase 4/6 inhibitors in combination with aromatase inhibitors led to high expectations from the analysis of the overall survival of patients with HR+/HER2- metastatic breast cancer. Of the three drugs in the group, the final data were obtained in the MONALEESA-2 and PALOMA-2 studies, while a statistically significant difference in median overall survival was achieved only with the use of ribociclib. The review discusses possible factors that could affect the final results of the presented studies. The effect of ribociclib on the value of OS in clinically unfavorable prognostic subgroups (for example, patients with visceral metastases) and on progression-free survival depending on the expression of molecular genetic factors that worsen patient survival (such as Rb, p16, Ki-67, CDKN2A, CCND1, ESR1) was analyzed.The combination of ribociclib and aromatase inhibitors has proven to be an advantage in the treatment of patients with HR+/HER2- metastatic breast cancer in terms of increasing both progression-free survival and overall survival. Efficacy has been proven in subgroups with clinical and molecular adverse prognostic factors.

Luminal metastatic HER2-negative breast cancer remains one of the most common cancers in oncological practice. This disease still remains incurable. Endocrine therapy remained the standard therapy of choice for disseminated patients for a long time. The search for new effective drugs, development of strategies that can overcome primary and secondary resistance to endocrinotherapy has shown that the CDK4/6-inhibitors group can improve not only the short-term treatment outcomes, but also affect the overall survival of patients, which has been demonstrated in a number of phase III studies. Along with that, the use of CDK4/6 inhibitors maintains a good quality of life, allows patients to maintain professional and social activities, which is of great importance for long-term prospects. Given that the endocrine therapy combined with CDK4/6-inhibitors today is the new standard of therapy in patients with luminal HER2- negative breast cancer, knowing how to use this therapy in daily clinical practice is crucial. Know and apply innovative drugs in clinical practice and the management of regimen toxicity always my work demands close application. This article provides an overview of the data on the efficacy of ribociclib based on phase III registration studies. It also presents its own clinical experience demonstrating the feasibility of using a new group of drugs in patients both in pre- and postmenopausal women. The authors discussed the issues related to the modification of the regimen due to the toxicity of therapy, in particular, neutropenia and hepatotoxicity. They also showed the possibility of managing adverse events with the preservation of a long-term effect with no loss in quality of life.

In most cases triple negative breast cancer is characterized by an aggressive course of disease and early development of resistance to chemotherapy. Thereafter, the late-line treatment choice, usually after anthracyclines and taxanes, is problematic due to the limited amount of effective and low-toxic cytostatics. In our opinion, in this situation the use of eribulin which possesses unique antitumor action mechanisms is a good option. An illustrative case of a pronounced antitumor effect of eribulin in metastatic breast cancer with triple negative phenotype resistant to previous lines of chemotherapy is presented.