Novartis had been granted Breakthrough Therapy designation by the US Food and Drug Administration for ribociclib, in combination with letrozole, for treating hormone-receptor-positive, human epidermal growth factor receptor-2-negative advanced or metastatic breast cancer. Ribociclib is a selective cyclin-dependent kinase (CDK4/6) inhibitor.

Ribociclib represents a class of drugs that help slow the progression of cancer by inhibiting CDK4/6 proteins. These proteins, when over-activated in a cell, can enable cancer cells to grow and divide too quickly. The drug has been studied in non-clinical models and is currently being evaluated in combination with additional endocrine agents as part a clinical trial program. Ribociclib is not approved for any indication in any market at this time.

Source: Novartis