Kisqali was developed by Novartis Institutes for BioMedical Research (NIBR) under a research collaboration with Astex announced in December 2005. Kisqali is a selective CDK inhibitor, a new class of drugs that help slow the progression of cancer by inhibiting two proteins called CDK 4 and 6 (CDK4/6). These proteins, when over-activated in a cell, can enable cancer cells to grow and divide too quickly.