Role of ribociclib in treatment of luminal Her-2-negative mBC with CNS metastases

For patients with the metastatic subtype of luminal HER-2-negative (HR+/HER2-) breast cancer (mBC) in the absence of visceral crisis, the gold standard of treatment is a combination of CDK4/6 inhibitors and aromatase inhibitors, regardless of their menopausal status and the sites of metastasis. The effectiveness of this approach was confirmed in the MONARCH, PALOMA, MONALEESA study cycles for the drugs abemaciclib, palbociclib and ribociclib, respectively. Metastasis in the central nervous system (CNS) in breast cancer complicates the treatment of patients and leads to the search for new approaches to the choice of therapy. To date, neurosurgical and radiosurgical techniques are actively used, however, drug therapy still stands for the leading positions. Data on the use of CDK4/6 inhibitors or aromatase inhibitors in patients with CNS metastases are limited. Most studies did not include patients with CNS metastases, only PALOMA-2,3 and MONALEESA-3 studies allowed the inclusion of patients with either “inactive” CNS metastases or after exposure to local treatment methods (for example, radiosurgery, radiotherapy, or surgery). In the study of real clinical practice of combined endocrine therapy with ribociclib (CompLEEment-1) allowed the inclusion of patients with active brain metastases (n = 51), while the subgroup analysis demonstrated the benefits of using a combination of ribociclib and aromatase inhibitors in patients in this difficult clinical situation. In the article, the authors review the available data from randomized clinical trials and real clinical practice, and also illustrate with their own observation.