Why are CDK4/6 inhibitor drugs used in CDK4/6 inhibitor therapy?

CDK4 and CDK6 are proteins that help a cell move from a resting stage into the stage where it copies its contents and divides. Some cancers rely heavily on this pathway to keep growing. A CDK4/6 inhibitor blocks these signals, which can hold cancer cells in an earlier part of the cell cycle and limit their multiplication.

These medicines are often used with hormone therapy for selected hormone-receptor-positive, HER2-negative breast cancers, although the suitable combination depends on the diagnosis and previous treatment. They are not appropriate for every cancer or every person. Treatment may be given in cycles, with blood tests and symptom checks to guide the next dose.

Take the medicine on the schedule provided and check before starting new medicines, supplements, or grapefruit products because interactions can matter. Keep appointments for blood counts and liver tests. Tell your team about fever, infection symptoms, unusual bruising, diarrhoea, mouth sores, or marked tiredness. Do not change the dose or pause treatment without instructions.

Call your care team urgently for a fever, chills, breathing difficulty, a new cough, severe weakness, yellowing of the skin, or bleeding that does not settle. These can signal infection, lung inflammation, liver problems, or reduced blood-cell counts and need prompt assessment.

Ask why this drug and combination fit your tumour, how the cycle is organised, which tests are needed, and what to do after a missed dose. Discuss contraception, interactions, infection precautions, likely side effects, and when treatment might be adjusted.