Monoclonal Antibody Side Effects | American Cancer Society (2023)

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  • What mAbs are made of
  • Types of mAbs used to treat cancer
  • Possible side effects of monoclonal antibodies

One way the body's immune system attacks foreign substances is by making large numbers of antibodies. An antibody is a protein that sticks to a specific protein called an antigen. Antibodies circulate throughout the body until they find and attach to the antigen. Once attached, they can force other parts of the immune system to destroy the cells containing the antigen.

Researchers can design antibodies that specifically target a certain antigen, such as one found on cancer cells. They can then make many copies of that antibody in the lab. These are known as monoclonal antibodies (mAbs or Moabs).

Monoclonal antibodies are used to treat many diseases, including some types of cancer. To make a monoclonal antibody, researchers first have to identify the right antigen to attack. Finding the right antigens for cancer cells is not always easy, and so far mAbs have proven to be more useful against some cancers than others.

NOTE: Some monoclonal antibodies used to treat cancer are referred to as targeted therapy because they have a specific target on a cancer cell that they aim to find, attach to, and attack. But other monoclonal antibodies act like immunotherapy because they make the immune system respond better to allow the body to find and attack cancer cells more effectively.

What mAbs are made of

Monoclonal antibodies are man-made proteins that act like human antibodies in the immune system. There are 4 different ways they can be made and are named based on what they are made of.

  • Murine: These are made from mouse proteins and the names of the treatments end in -omab.
  • Chimeric: These proteins are a combination of part mouse and part human and the names of the treatments end in -ximab.
  • Humanized: These are made from small parts of mouse proteins attached to human proteins and the names of the treatments end in -zumab
  • Human: These are fully human proteins and the names of the treatments end in -umab.

Types of mAbs used to treatcancer

Naked monoclonal antibodies

Naked mAbs are antibodies that have no drug or radioactive material attached to them. They work by themselves. These are the most common type of mAbs used to treat cancer. Most naked mAbs attach to antigens on cancer cells, but some work by binding to antigens on other, non-cancerous cells, or even free-floating proteins. Naked mAbs can work in different ways.

  • Some boost a person’s immune response against cancer cells by attaching to them and acting as a marker for the body’s immune system to destroy them. An example is alemtuzumab (Campath), which is used to treat some patients with chronic lymphocytic leukemia (CLL). Alemtuzumab binds to the CD52 antigen, which is found on cells called lymphocytes (which include the leukemia cells). Once attached, the antibody attracts immune cells to destroy these cells.
  • Some naked mAbs boost the immune response by targeting immune system checkpoints. (See Immune Checkpoint Inhibitors and Their Side Effects.)
  • Other naked mAbs work mainly by attaching to and blocking antigens on cancer cells (or other nearby cells) that help cancer cells grow or spread. For example, trastuzumab (Herceptin) is an antibody against the HER2 protein. Breast and stomach cancer cells sometimes have large amounts of this protein on their surface. When HER2 is activated, it helps these cells grow. Trastuzumab binds to these proteins and stops them from becoming active.

Conjugated monoclonal antibodies

Conjugated mAbs are combined with a chemotherapy drug or a radioactive particle. These mAbs are used as a homing device to take one of these substances directly to the cancer cells. The mAb circulates throughout the body until it can find and hook onto the target antigen. It then delivers the toxic substance where it is needed most. This lessens the damage to normal cells in other parts of the body. Conjugated mAbs are also sometimes referred to as tagged, labeled, or loaded antibodies.

  • Radiolabeled antibodies: Radiolabeled antibodies have small radioactive particles attached to them. Ibritumomab tiuxetan (Zevalin) is an example of a radiolabeled mAb. This is an antibody against the CD20 antigen, which is found on lymphocytes called B cells. The antibody delivers radioactivity directly to cancer cells. It is made of both an mAb drug (rituximab) and a radioactive substance (Yttrium-90). Treatment with this type of antibody is sometimes known as radioimmunotherapy (RIT). The drug and radiation are delivered directly to the target cells because the mAb looks for the target, then the radiation affects the target and nearby cells to a certain extent.
  • Antibody-drug conjugates (chemolabeled antibodies): These mAbs have powerful chemotherapy (or other) drugs attached to them. Examples include:
    • Brentuximab vedotin (Adcetris), an antibody that targets the CD30 antigen (found on lymphocytes), attached to a chemo drug called MMAE.
    • Ado-trastuzumab emtansine (Kadcyla, also called TDM-1), an antibody that targets the HER2 protein, attached to a chemo drug called DM1.

Bispecific monoclonal antibodies

These drugs are made up of parts of 2 different mAbs, meaning they can attach to 2 different proteins at the same time. An example is blinatumomab (Blincyto), which is used to treat some types of leukemia. One part of blinatumomab attaches to the CD19 protein, which is found on some leukemia and lymphoma cells. Another part attaches to CD3, a protein found on immune cells called T cells. By binding to both of these proteins, this drug brings the cancer cells and immune cells together, which is thought to cause the immune system to attack the cancer cells.

Possible side effects of monoclonal antibodies

Monoclonal antibodies are given intravenously (injected into a vein). The antibodies themselves are proteins, so giving them can sometimes cause something like an allergic reaction. This is more common while the drug is first being given. Possible side effects can include:

  • Fever
  • Chills
  • Weakness
  • Headache
  • Nausea
  • Vomiting
  • Diarrhea
  • Low blood pressure
  • Rashes

Compared with chemotherapy drugs, naked mAbs tend to have fewer serious side effects. But they can still cause problems in some people. Some mAbs can have side effects that are related to the antigens they target. For example:

  • Bevacizumab (Avastin) is an mAb that targets a protein called VEGF that affects tumor blood vessel growth. It can cause side effects such as high blood pressure, bleeding, poor wound healing, blood clots, and kidney damage.
  • Cetuximab (Erbitux) is an antibody that targets a cell protein called EGFR, which is found on normal skin cells (as well as some types of cancer cells). This drug can cause serious rashes in some people.
(Video) What to know before getting a monoclonal antibody treatment
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Monoclonal Antibody Side Effects | American Cancer Society (1)

(Video) Immunotherapy

The American Cancer Society medical and editorial content team

Our team is made up of doctors andoncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

(Video) Monoclonal Antibodies | How to Turn Cancer Against Itself

Acrotech Biopharma. What is Zevalin? Accessed at on December 19, 2019.

American Society of Clinical Oncology (ASCO). ASCO Annual Meeting 2019: Immunotherapy for lung cancer, gastrointestinal cancers and targeted therapy for breast cancer. Accessed at on December 19, 2019.

(Video) How Monoclonal Antibodies Treat Cancer

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Bayer VR, Davis ME, Gordan RA, et al. Immunotherapy. In Olsen MM, LeFebvre KB, Brassil KJ, eds. Chemotherapy and Immunotherapy Guidelines and Recommendations for Practice. Pittsburgh, PA: Oncology Nursing Society; 2019:149-189.

Bousquet E, Zarbo A, Tournier E, et al. Development of papulopustular rosacea during nivolumab therapy for metastatic cancer. Act Derm Venereol. 2017; 97(4):539—540.

Hong D, Sloane DE. Hypersensitivity to monoclonal antibodies used for cancer and inflammatory or connective tissue disease. Ann Allergy Asthma Immunol. 2019; 123(1):35-41.

Kaunitz GJ, Loss M, Rizvi et al. Cutaneous eruptions in patients receiving immune checkpoint blockade: Clinicopathologic analysis of the nonlichenoid histologic pattern. Am J Surg Pathol. 2017; 41(10):1381-1389.

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Last Revised: November 17, 2022

American Cancer Society medical information is copyrightedmaterial. For reprint requests, please see our Content Usage Policy.

(Video) Monoclonal antibody treatment: Why it's so difficult to distribute


What are the side effects of monoclonal antibodies cancer? ›

What types of side effects do monoclonal antibody drugs cause?
  • Allergic reactions, such as hives or itching.
  • Flu-like signs and symptoms, including chills, fatigue, fever, and muscle aches and pains.
  • Nausea, vomiting.
  • Diarrhea.
  • Skin rashes.
  • Low blood pressure.

What are the side effects of monoclonal antibody infusions? ›

In previous trials, some patients receiving these antibody infusions have reported side effects including nausea, diarrhea, vomiting, fever, chills, headache, coughing or wheezing, a drop in blood pressure, swelling or inflammation of the skin, throat irritation, rash, itching, muscle pain/ache, and dizziness.

What is a disadvantage of using monoclonal antibodies as treatment? ›

Despite their many advantages, a drawback of monoclonal antibodies is that they are more time-consuming and expensive to produce than polyclonals. If a monoclonal has not yet been developed, researchers may consider using an existing polyclonal antibody, then switching to a monoclonal if one becomes available.

Can you get worse after monoclonal antibodies? ›

Worsening symptoms after monoclonal antibody treatment: You may experience new or worsening symptoms after infusion, including fever, difficulty breathing, rapid or slow heart rate, tiredness, weakness or confusion.

Do you feel sick after monoclonal antibodies? ›

What are the side effects of the antibody treatment? The most common reported side effects with bamlanivimab are nausea, diarrhea, dizziness, headache, itchiness, and vomiting. The most common reported side effects with casirivimab/imdevimab are nausea and vomiting, hyperglycemia, and pneumonia.

What are the neurological side effects of monoclonal antibodies? ›

Several neurological disorders have been associated with the use of monoclonal antibodies (mAbs), especially those targeting tumor necrosis factor (TNF) and its receptors. These disorders include, among others, multiple sclerosis, optic neuritis, and various forms of peripheral demyelinating neuropathy.

Why are monoclonal antibodies not widely used? ›

The interactions in the human body has resulted in unwanted side effects. This means they are not as widely used by doctors as originally thought. Monoclonal antibodies are also very expensive to produce.

Do monoclonal antibodies cause immunosuppression? ›

Therefore, mAbs can be considered to have a high potential for immunotoxicity, which is reflected in the clinical experience accumulated on mAbs-induced adverse effects related to immunosuppression, immunostimulation and hypersensitivity (immunogenicity).

How safe are monoclonal antibodies? ›

Monoclonal antibody therapy for COVID-19 is well tolerated with minimal risks. Injection site reactions and infusion-related reactions are the most commonly reported adverse events. Monoclonal antibody therapy is not indicated in severe cases requiring hospitalization.

Can monoclonal antibodies cause organ damage? ›

There is no evidence that any of the anti-SARS-CoV-2 monoclonal antibodies cause serum enzyme elevations or clinically apparent liver injury.

How long do monoclonal antibodies stay in your body? ›

But though these antibodies mimic the infection-fighting work of the immune system, they don't last forever – typically, a monoclonal antibody will stick around for a number of weeks or months.

Can monoclonal antibodies cause cytokine storm? ›

Its activation in COVID-19 can cause a "cytokine storm" with serious biological and clinical consequences.

What are the reactions to monoclonal antibodies? ›

If you notice changes such as pain, redness, drainage, numbness, tingling, or other concerning symptoms near your injection site, call your healthcare provider. It is rare, but some people can have a severe allergic reaction to monoclonal antibody treatment.

Is it better to get monoclonal antibodies? ›

When administered to non-hospitalized, high-risk patients as soon as possible after positive viral testing for COVID-19 and within 7 days of symptom onset, monoclonal antibodies may improve symptoms and reduce risk of hospitalizations and death associated with COVID-19.

What are the contraindications for monoclonal antibodies? ›

Contraindications include allergic, neoplastic, infective diseases, but also hypertension, cardiac failure and pregnancy.

What are the side effects of infusions? ›

What are the side effects of infusion therapy? Side effects of some medication during infusions include itching, rash, hives, fever, chills, cough, redness in the face or neck area, swelling of the tongue, lips or eyelids, nausea, muscle or joint pain. Although these allergic reactions may occur, they are rare.

Which type of monoclonal antibody is most likely to cause a hypersensitivity reaction? ›

Beta-type reactions

Variable murine regions of monoclonal antibodies (MoAbs) are complete antigens, xenoantigens, capable of inducing hypersensitivity reactions.

What are adverse reactions to Regeneron? ›

Side effects of Regen-Cov include: infusion-related reactions (hives, itching, flushing, fever, shortness of breath, chest tightness, nausea, vomiting, rash) and. severe allergic reactions (anaphylaxis).

Can monoclonal antibodies cause psychosis? ›

In the Vigibase database, we found a 0.1–0.4% prevalence of spontaneously-reported psychosis ADRs from treatment with mAb.

What is true about monoclonal antibodies? ›

Monoclonal antibodies are clones of your body's antibodies that are made in a laboratory, meant to stimulate your immune system. Monoclonal antibodies as therapies are more targeted than some other types of treatments and have been more successful at treating some types of diseases, including some cancers.

Are monoclonal antibodies cytotoxic? ›

Trigger the immune system

Some MABs attach themselves to cancer cells, making it easier for the cells of the immune system to find them. This process is called antibody-dependent cell-mediated cytotoxicity or ADCC.

How does chemotherapy compare to monoclonal antibodies? ›

When compared to chemotherapy, monoclonal antibodies are precise in the way they attack cancer cells. Fewer normal cells are being affected by the therapy, which results in fewer side effects.

Are monoclonal antibodies a live virus? ›

Antibody treatments do not contain any live virus, so there is no risk you will get COVID-19 from mAb treatment. However, the antibody treatment may have side effects. Please talk with your healthcare provider about possible side effects and what to do if you experience them.

What autoimmune disease has monoclonal antibodies? ›

Part of a class of therapeutic drugs known as biologics, monoclonal antibodies are used in immunotherapy to treat autoimmune (AI) diseases like rheumatoid arthritis (RA), as well as certain cancers, viral infections, gastrointestinal diseases, and more.

Do monoclonal antibodies interact with other drugs? ›

Although mAbs do not share direct targets or mechanisms of disposition with small-molecule drugs (SMDs), combining therapeutics of both types can increase the risk of adverse effects and treatment failure.

Why do I have to wait 90 days after monoclonal antibodies? ›

It is recommended that patients wait 90 days after receiving a COVID-19 monoclonal antibody treatment before starting or continuing a COVID-19 vaccine or vaccine series. The monoclonal antibody therapy is expected to provide a temporary immunity during this period of time.

What diseases can monoclonal antibodies treat? ›

Monoclonal antibody therapies are used to treat or prevent an increasingly broad range of diseases, including various cancers, auto-immune and metabolic diseases. Some examples include Crohn's disease, asthma, rheumatoid arthritis and bladder cancer.

Can monoclonal antibodies cause gastrointestinal problems? ›

The use of anti-angiogenic monoclonal antibodies can lead to bowel perforations, whereas epidermal growth factor receptor inhibitors and anti-HER2 agents are frequently associated with diarrhea.

Are monoclonal antibodies natural in body? ›

These antibodies are made naturally once our bodies are infected with or vaccinated against a virus. Antibodies that recognize one specific part of a virus or bacterium can be copied in a laboratory. The lab-made antibodies are called monoclonal antibodies.

What are the symptoms of monoclonal? ›

Symptoms of monoclonal gammopathies vary among these conditions, but can include:
  • Anemia or low red blood cells counts.
  • Lack of energy (fatigue) or tiredness.
  • Weakness.
  • Pain in the bones or soft tissues.
  • Tingling or numbness in the feet or hands.
  • Infection that keeps coming back.
  • Increased bruising.
  • Bleeding.

How many times can you get the monoclonal antibodies? ›

Monoclonal antibody therapy is a one-time treatment.

Should I take Paxlovid or not? ›

Paxlovid is the first-choice treatment for mild to moderate COVID in people with a higher risk of severe illness. In initial clinical studies, it was about 90% effective at preventing COVID-related hospitalization and death.

How long does natural immunity to COVID last? ›

Share on Pinterest Research shows that the antibodies that develop from COVID-19 remain in the body for at least 8 months. Immunity can occur naturally after developing COVID-19, from getting the COVID-19 vaccination, or from a combination of both.

What are the symptoms of cytokine storm in Covid? ›

Cytokine release syndrome (CRS) happens when your immune system responds to infection or immunotherapy drugs more aggressively than it should. CRS symptoms include fever, nausea, fatigue and body aches.
They may include:
  • Fever.
  • Chills.
  • Tiredness.
  • Nausea and vomiting.
  • Diarrhea.
  • Headaches.
  • Cough.
  • Low blood pressure.
Apr 7, 2022

What are the symptoms of cytokine storm post Covid? ›

Symptoms of cytokine storm can include confusion, shortness of breath, lethargy, and more. It is treated with supportive care, which may include fluids, breathing assistance, and treatment of the underlying medical condition.

What is the death rate of cytokine storm in Covid? ›

Results: The clinical outcome of COVID-19 patients following medical therapy was either cured (85.7%) or died (14.3%), with 14.3% patients reported to have cytokine storm, from which 23.1% led to fatalities.

What do monoclonal antibodies do for cancer patients? ›

Monoclonal antibodies (MABs) are a type of targeted drug therapy. These drugs recognise and find specific proteins on cancer cells. There are many different MABs to treat cancer. They work in different ways to kill the cancer cell or stop it from growing.

What is the success rate of monoclonal antibody cancer treatment? ›

In a study involving 48 patients with chronic or small lymphocytic leukaemia, rituximab therapy resulted in an overall response rate of 58%, with 9% complete responses (21). Similar success has been reported for treatment of follicular lymphoma (22) and diffuse large B-cell lymphoma (23).

Which kinds of cancer have been treated with monoclonal antibodies? ›

Examples of MABS that work in this way include:
  • rituximab (Mabthera) – a treatment for chronic lymphocytic leukaemia (CLL) and some types of non Hodgkin lymphoma.
  • cetuximab (Erbitux) – a treatment for advanced bowel cancer and head and neck cancer.
  • trastuzumab (Herceptin) – used to treat breast cancer and stomach cancer.

What is the new monoclonal antibody treatment for cancer? ›

Monoclonal antibody therapy is a form of targeted treatment that uses lab-created antibodies that find and kill specific cancer cells. Physicians who treat cancer (oncologists) also use monoclonal antibody therapy to boost the immune system's ability to defend against cancer.

What is the most common targets of monoclonal antibodies used in cancer treatments? ›

Immune checkpoint targets of monoclonal antibodies. The most well-known and promising type of mAb therapy for cancer is the blockade of immune checkpoints (Figure 2).

Is monoclonal antibodies safe? ›

Monoclonal antibody therapy for COVID-19 is well tolerated with minimal risks. Injection site reactions and infusion-related reactions are the most commonly reported adverse events. Monoclonal antibody therapy is not indicated in severe cases requiring hospitalization.

How long do monoclonal antibodies stay in your system? ›

But though these antibodies mimic the infection-fighting work of the immune system, they don't last forever – typically, a monoclonal antibody will stick around for a number of weeks or months.

Why is monoclonal antibody treatment stopped? ›

The FDA said last week that bebtelovimab, a monoclonal antibody drug given through a vein, is no longer authorized because it is not effective against the leading strains of COVID-19.

Which cancer trial using monoclonal antibody finds remission in every patient? ›

June 6, 2022 – A small clinical trial with 12 rectal cancer patients found remission in 100% of them, according to a new paper published in TheNew England Journal of Medicine. All the patients took dostarlimab, a monoclonal antibody, every 3 weeks for 6 months.

Are monoclonal antibodies better than chemotherapy? ›

Monoclonal antibody side effects vary, but are usually mild

When compared to chemotherapy, monoclonal antibodies are precise in the way they attack cancer cells. Fewer normal cells are being affected by the therapy, which results in fewer side effects.

How long have monoclonal antibodies been used to treat cancer? ›

It has been more than three decades since the first monoclonal antibody was approved by the United States Food and Drug Administration (US FDA) in 1986, and during this time, antibody engineering has dramatically evolved. Current antibody drugs have increasingly fewer adverse effects due to their high specificity.

How much do monoclonal antibodies cost for cancer? ›

Cost is an issue for most monoclonal antibodies. They are some of the most expensive drugs in the world. The average treatment in the US can cost between $15,000 and $200,000 per year.

How many monoclonal antibodies are approved for cancer treatment? ›

Twenty-four monoclonal antibodies (mAbs) targeted to a total of 16 different antigens are currently approved for the treatment of an increasing number of cancers.

Is Regeneron used for cancer? ›

About Regeneron

Our medicines and pipeline are designed to help patients with eye diseases, allergic and inflammatory diseases, cancer, cardiovascular and metabolic diseases, pain, hematologic conditions, infectious diseases and rare diseases.


1. How Do Drugs Work: monoclonal Antibody: Anti-Neoplastic Drug -- Trastuzumab (Herceptin®)
(British Pharmacological Society)
2. What are antibody-drug conjugates and how do they work against cancer?
3. Antibody Drug Conjugates and Recent Applications in Breast Cancer Treatment
4. What is Monoclonal Antibody Therapy?
(Augusta University Health)
5. The development of anti-nectin monoclonal antibodies
6. What is Regeneron COVID-19 Monoclonal Antibody Treatment?
(Columbus Regional Health)
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