What are monoclonal antibodies?
Monoclonal antibodies are proteins made in a laboratory that mimic the natural antibodies produced by your immune system to fight off illness. They bind to targets in your body, such as cancer cells, viruses or other foreign substances. They can be used to diagnose and treat many different conditions.
Antibody receptors, or antibodies, are proteins that circulate through your body looking for targets called antigens on the surface of unhealthy cells. Like natural antibodies, monoclonal antibodies attach to antigens and stimulate your immune system to attack them or stop cells from dividing.
Some monoclonal antibodies are considered a type of targeted therapy since they target specific proteins on certain cancer cells. Other monoclonal antibodies are seen as immunotherapy, as they help your immune system work better.
Types of monoclonal antibodies
A wide range of monoclonal antibodies have been approved to fight cancer, autoimmune conditions, cardiovascular diseases, musculoskeletal disorders and viral infections. These therapies can be divided into three main categories based on how they work.
Conjugated monoclonal antibodies
Conjugated monoclonal antibodies carry a drug or radioactive particle directly to a cancer or disease cell, destroying the unhealthy cell while minimizing damage to healthy cells.
Monoclonal antibodies connected to drugs are known as antibody-drug conjugates. Monoclonal antibodies attached to radioactive particles may be referred to as radiolabeled antibodies or radioimmunotherapy. These medications release radiation in a specific way that kills cancer cells that express the antibody.
Naked monoclonal antibodies
Naked monoclonal antibodies work by themselves with no other drugs or radioactive materials attached to them. These are the most common types used to treat cancer.
Naked monoclonal antibodies can work in different ways to boost your immune response. For example, they can attach to unhealthy cells or to “checkpoint” proteins your immune system uses to identify unhealthy cells. Once they’ve attached, your immune system has an easier time identifying and destroying the unhealthy cells.
Another type of naked monoclonal antibody binds to proteins on the cancer cells and stops them from growing and dividing.
Bispecific monoclonal antibodies
Bispecific monoclonal antibodies contain two antibodies that can bind to two target proteins, for example, a protein on a cancer cell and one on an immune cell. Bispecific monoclonal antibodies are relatively new. The Food and Drug Administration has approved several types to treat cancer and blood disorders, but more are being developed.
What types of conditions do monoclonal antibodies treat?
Monoclonal antibodies treat various conditions, including cancer, autoimmune conditions (like rheumatoid arthritis and lupus), infections (such as COVID-19), neurological disorders (such as multiple sclerosis), and eye conditions (like macular degeneration). They're also being studied for Alzheimer's and diabetes, offering targeted treatment options for a variety of conditions.
How do monoclonal antibodies work?
Monoclonal antibodies work in different ways to identify and attack unhealthy cells or foreign substances in your body. Each monoclonal antibody recognizes one particular protein, which could be on the surface of a cancer cell or a cell that is part of your immune system.
Some antibodies bind to the proteins on abnormal cells, acting as markers and stimulating your immune system to attack these cells. This can help your immune system distinguish cancer cells from healthy cells. They can also carry drugs or radioactive particles directly to target cells.
Other antibodies work on the proteins that are naturally in your body. For example, they could stop proteins from blocking an immune response to cancer cells or support the regulation of LDL cholesterol.
Cancer cells can make large amounts of molecules called growth factor receptors. These sit on the surface of cells and send signals to make them divide. Monoclonal antibodies can block these receptors or their signals, stopping the cells from multiplying. Other drugs can prevent tumors from developing the blood vessels they need to grow larger.
Monoclonal antibodies can also target viruses in several ways. For example, they can bind to a virus and stop it from entering a healthy cell.
What is monoclonal antibody therapy for cancer?
Monoclonal antibodies are used to treat various cancers, including breast, prostate, lung, colorectal, head and neck cancers and certain types of leukemia. They are often combined with other treatments, including chemotherapy, radiation therapy and surgery.
Monoclonal antibodies are sometimes referred to as targeted therapies, since they target specific proteins on specific types of cancer cells. They can also be a form of immunotherapy, which means they stimulate your immune system to attack the cancer. Your doctor might order blood tests or a biopsy to see whether your cancer will respond to monoclonal antibody treatment and, if so, which drug to use.
Monoclonal antibodies are usually injected directly into a vein or under your skin (subcutaneously) at an outpatient center. How often you will need treatment will depend on the type of cancer you have, the drug being used and whether it is combined with any other therapy. Your treatment could last from a few weeks to several months or longer. You might be given treatment in cycles with scheduled rest periods for your body to recover.
Your doctor will monitor you closely after treatment to see how you respond and whether you experience any side effects.
Monoclonal antibodies side effects
Monoclonal antibody treatments generally cause fewer side effects than traditional chemotherapy, as they focus on targeting abnormal cells while leaving healthy cells mostly unharmed. However, some side effects can still occur and may vary from person to person.
Common side effects include:
- Pain, swelling or redness at the injection site
- Reactions during the infusion, like chills, fever, headache or rash
- Other possible side effects, depending on the treatment, can include:
- High blood pressure or bleeding issues
- Skin rashes
- Heart or lung problems
- Mouth sores or nausea
Your healthcare team will help monitor and manage any side effects during your treatment.