How Do Antineoplastic Proteasome Inhibitors Work?

Antineoplastic proteasome inhibitors are a class of drugs used to treat multiple myeloma (cancer that forms in a type of white blood cell called a plasma cell) and mantle cell lymphoma (fast-growing cancer that begins in the cells of the immune system).

Human body cells contain protein complexes called “proteasomes” (large protein complex that helps destroy other cellular proteins) responsible for maintaining the concentration of proteins in cells and disposing of damaged proteins. This process of degradation is called “proteolysis” and the enzymes that participate are called "proteases."

Damaged or unrequired proteins are identified by the proteases through the presence of “ubiquitin” conjugated to the targeted protein, and the enzymes responsible for this tagging are called "ubiquitin ligases." This overall process of protein degradation is termed as the ubiquitin–proteasome pathway.

Proteasome inhibitors are drugs that block the action of proteasomes, resulting in the accumulation of polyubiquitinated proteins, which may cause cell cycle arrest, apoptosis (death of cells that occurs as a normal and controlled part of an organism's growth or development), and inhibition of tumor growth. 

Proteasome inhibitors are administered as a solution (liquid) intravenously (into a vein) or subcutaneously (under the skin) and via oral route.

Antineoplastic proteasome inhibitors are used to treat conditions such as:

• Mantle cell lymphoma (fast-growing cancer that begins in the cells of the immune system).
• Multiple myeloma (cancer that forms in a type of white blood cell called a plasma cell)

Some of the common side effects include:

• Nausea
• Vomiting
• Constipation
• Diarrhea
• Abdominal pain
• Headache
• Tiredness/weakness
• Loss of appetite
• Pain, redness, bruising, bleeding, or hardness at the injection site
• Unusual bleeding or bruising

Other rare side effects include:

• Dizziness 
• Fatigue 
• Hair loss
• Anemia (low red blood cell count)
• Insomnia 
• Chest pain
• Shortness of breath
• Chills, sore throat, fever, or cough
• Thrombocytopenia (low blood platelet count)
• Peripheral edema (swelling of lower legs or hands)
• Hyperglycemia (high blood glucose level)
• Rash/hives/itching
• Increased serum creatinine 
• Hypokalemia (low blood potassium level)
• Hypercalcemia (high blood calcium level) 
• Pneumonia (an infection that inflames the air sacs in one or both the lungs)
• Hypertension (high blood pressure)
• Upper respiratory tract infection
• Blurred vision
• Yellowing of skin or eyes
• Peripheral neuropathy (damage to one or more groups of nerves)

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 proteasome inhibitors include:

• Bortezomib
• Carfilzomib
• Ixazomib
• Kyprolis
• Ninlaro
• Velcade