Ribociclib is primarily used in the treatment of certain types of breast cancer. It is specifically indicated for hormone receptor-positive, HER2-negative advanced or metastatic breast cancer in combination with other therapies like aromatase inhibitors or fulvestrant. The drug works by inhibiting cyclin-dependent kinases 4 and 6 (CDK4/6), which play a crucial role in cell division and cancer progression. By blocking these enzymes, Ribociclib helps to slow down or stop the growth of cancer cells. It is often prescribed for postmenopausal women and is administered orally, making it a convenient option for long-term treatment. Clinical trials have shown that Ribociclib, when used in combination with endocrine therapy, significantly improves progression-free survival in patients. Regular monitoring of blood counts and liver function is essential during treatment due to potential side effects such as neutropenia and hepatotoxicity.