How Do Antineoplastic HDAC Inhibitors Work?

Antineoplastic histone deacetylase (HDAC) inhibitors are a class of drugs used to treat multiple myeloma (a type of cancer of the bone marrow), relapsed or refractory peripheral T-cell lymphoma (a form of cancer that begins in certain cells of the immune system), and cutaneous T-cell lymphoma (a rare type of cancer that begins in white blood cells called T cells [T lymphocytes]).

HDAC inhibitors are anti-cancer medications with a sulfonamide-hydroxamide structure that works by inhibiting an enzyme histone deacetylase. They undergo reduction within the cell to release a zinc-binding thiol that binds to a zinc atom in the binding pocket of zinc-dependent histone deacetylase to block its activity, thus inducing apoptosis (a genetically regulated form of cell death).

HDAC inhibitors are administered as a solution (liquid) to be injected intravenously (into a vein) once a day on Days 1 to 5 of a 21-day treatment cycle and orally once daily with or without food.

HDAC inhibitors work in the following ways:

• They are chemotherapy medications that work by slowing or stopping the growth of cancer cells.
• They bind to the zinc-dependent pocket of an enzyme known as “histone deacetylase” and inhibit its activity leading to cell death.

Antineoplastic HDAC inhibitors are used to treat conditions such as:

• Peripheral T-cell lymphoma (a form of cancer that begins in a certain cells of the immune system)
• Multiple myeloma (cancer that forms in a type of white blood cell called a plasma cell)
• Cutaneous T-cell lymphoma (a rare type of cancer that begins in white blood cells called T cells [T lymphocytes])
• Melanoma (a type of skin cancer that occurs when pigment producing cells called melanocytes mutate and begin to divide uncontrollably)

Some of the common side effects include:

• Nausea
• Vomiting
• Constipation
• Diarrhea
• Headache
• Tiredness/weakness
• Taste changes
• Mouth sores
• Loss of appetite
• Dryness of mouth
• Pain, redness, swelling, hardness, or itching at the injection site

Other rare side effects include:

• Dizziness 
• Fatigue 
• Weight loss
• Hair loss
• Chest pain
• Anemia (low red blood cell count)
• Insomnia 
• Shortness of breath
• Chills, sore throat, fever, or cough
• Rash/hives/itching
• Yellowing of the skin or eyes
• Thrombocytopenia (low blood platelet count)
• Hypotension (low blood pressure)
• Hypocalcemia (low blood calcium level)
• Hypophosphatemia (low blood phosphate level)
• Increased creatinine (a waste product formed by the normal breakdown of muscle cells)
• Swelling hands/ankles/feet
• Painful, frequent, burning, or difficult urination
• Peripheral edema (swelling of lower legs or hands)

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 HDAC inhibitors include:

• Beleodaq
• Belinostat
• Farydak
• Istodax
• Panobinostat
• Romidepsin
• Vorinostat
• Zolinza