How Do Antineoplastic CDK Inhibitors Work?

Antineoplastic cyclin-dependent kinase (CDK) inhibitors are a class of drugs used to treat hormone receptor-positive, advanced breast cancer (cancer that depends on hormones such as estrogen to grow or breast cancer that has spread to other parts of the body in people who have already been treated with an antiestrogen medication and chemotherapy), marginal zone lymphoma (slow growing cancer that begins in a type of white blood cells that normally fights infection) and follicular lymphoma (a type of cancer that begins in the white blood cells) and to decrease the risk of myelosuppression (a decrease in red blood cells, white blood cells, and platelets) from certain chemotherapy medications in adults with small cell lung cancer. 

CDK inhibitors are antitumor agents and dual inhibitors of proteins called cyclin-dependent kinases 4 (CDK4) and 6 (CDK6) (when overactivated, can enable cancer cells to grow and divide quickly) that are involved in the cell cycle and promotion of cancer cell growth. Blocking these proteins prevents cells from progressing, thereby inducing apoptosis (cell death).

CDK inhibitors are administered via intravenous (into a vein) and oral routes.

CDK inhibitors work in the following ways:

• They belong to a class of drugs called "kinase inhibitors" that work by inhibiting CDK4 and CDK6 proteins which help in preventing the growth and spread of cancer cells.
• They help in decreasing the amount of estrogen produced by the body which further helps in reversing or halting the growth of certain breast cancers.
• They block the action of an abnormal protein that signals cancer cells to multiply which helps to slow down or to halt the spread of cancer cells.
• In addition, they block the action of certain substances in the body to protect the cells in the bone marrow and immune system from damage during chemotherapy.

Antineoplastic CDK inhibitors are used to treat conditions such as:

• Breast cancer
• Chemotherapy-induced myelosuppression (most common dose-limiting and potentially fatal complication of cancer treatment)
• Marginal zone lymphoma (a group of slow-growing, non-Hodgkin's B-cell lymphomas)
• Follicular lymphoma (cancer that affects white blood cells called lymphocytes)

Some of the common side effects include:

• Nausea
• Vomiting
• Constipation
• Diarrhea
• Abdominal pain
• Headache
• Tiredness/weakness
• Taste changes
• Mouth sores
• Loss of appetite
• Joint/back pain
• Hot flashes
• Pain, redness, swelling, hardness, or itching at the injection site

Other rare side effects include:

• Dizziness 
• Excessive sweating
• Fatigue 
• Weight loss
• Hair loss
• Anemia (low red blood cell count)
• Insomnia (trouble falling and/or staying asleep)
• Shortness of breath
• Chills, sore throat, fever, or cough
• Rash/hives/itching
• Yellowing of the skin or eyes
• Swelling of the face, throat, tongue, lips, eyes, hands, feet, ankles, or lower legs
• Thrombocytopenia (low blood platelet count)
• Hypocalcemia (low blood calcium level)
• Hypokalemia (low blood potassium level)
• Hypophosphatemia (low blood phosphate level)
• Increased creatinine (a waste product formed by the normal breakdown of muscle cells)

Information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Generic and brand names of antineoplastic CDK inhibitors include:

• Abemaciclib
• Cosela
• Ibrance
• Kisqali
• Kisqali/femara copack
• Palbociclib
• Ribociclib
• Ribociclib/letrozole
• Trilaciclib
• Ukoniq
• Umbralisib
• Verzenio