Monoclonal Antibodies and Cancer Treatment: What to Know

Monoclonal antibodies (mAbs) are lab-grown immunoglobulins that identify and bind to a specific antigen. That is why they are widely used in targeted therapies, such as immunotherapy.

Monoclonal antibody-based immunotherapy has become a crucial part of cancer therapy nowadays. It is used in surgery, radiation, and chemotherapy. mAbs help inhibit tumor growth, mark cancer cells for destruction by immune cells, or deliver cytotoxic agents directly to the tumor site. 

Unlike traditional chemotherapy, which targets both healthy and cancerous cells, monoclonal antibodies used in cancer treatment identify and bind to specific epitopes on antigens present on the surface of cancer cells. 

As a result, mAbs help inhibit tumor growth, mark creduce the side effects of cancer treatment and improve treatment results. 

Types of mAbs Used in Cancer Treatment

Naked (Unconjugated) mAbs: These are the simplest form of mAbs, administered without any attached drugs or radioactive materials. They work by blocking signaling pathways or recruiting immune cells. Examples include:

• Rituximab (anti-CD20)

• Trastuzumab (anti-HER2)

Conjugated mAbs: These are linked to a toxic payload such as a chemotherapy drug or radioactive substance. They include:

• Trastuzumab emtansine (T-DM1): conjugated to a microtubule inhibitor

• Ibritumomab tiuxetan: conjugated with a radioisotope 

Bispecific mAbs: Engineered to bind two different antigens simultaneously. For example, blinatumomab targets both CD19 on B cells and CD3 on T cells (PMC7551545).

Source-based classification: mAbs are also classified based on their origin:

• -omab: fully murine

• -ximab: chimeric

• -zumab: humanized

• -umab: fully human

How mAbs Work in Cancer Therapy?

mAbs perform several functions in cancer treatment, including:

• Blocking Growth Signals: Some cancers depend on specific signaling pathways to grow and divide. mAbs such as trastuzumab (Herceptin) target the HER2 receptor, which is overexpressed in certain breast cancers. By blocking these receptors, the antibody prevents the cancer cell from receiving growth-promoting signals.

• Flagging Cancer Cells for Immune Destruction: Monoclonal antibodies can also act as flags to recruit immune cells. For instance, rituximab (Rituxan) targets CD20 on B-cell lymphomas. Once bound, it attracts natural killer (NK) cells and macrophages to destroy the marked cancer cell through antibody-dependent cell-mediated cytotoxicity (ADCC).

• Delivering Cytotoxic Agents: Some mAbs are conjugated with chemotherapy drugs or radioactive isotopes. These antibody-drug conjugates (ADCs) help deliver cytotoxic agents to the target cells.

For example, ado-trastuzumab emtansine (Kadcyla) links trastuzumab with the cytotoxic agent emtansine that releases the drug directly into HER2-positive tumor cells.

• Modulating the Immune System (Checkpoint Inhibitors):  The cancer cells use these proteins, such as PD-1 and PD-L1, to evade immune detection. At times, checkpoint inhibitors or mAbs like nivolumab and pembrolizumab help block these proteins. As a result, this helps mAbs restore T-cell activity and allow the immune system to fight against the tumor.

What are the side effects of monoclonal antibodies?

While monoclonal antibody treatments are generally well-tolerated, side effects can occur and vary depending on the specific drug and the patient’s immune response.

Mild to Moderate Side Effects:

• Infusion reactions: Fever, chills, rash, headache, or fatigue during or shortly after infusion.

• Nausea or diarrhea

• Skin rashes or itching

• Low blood pressure or dizziness

Severe Side Effects (Less Common):

• Allergic reactions: Especially with murine or chimeric antibodies.

• Immune-related adverse events (irAEs): For checkpoint inhibitors, such as inflammation of the lungs (pneumonitis), liver (hepatitis), or endocrine glands.

• Cardiotoxicity: Some mAbs, like trastuzumab, may cause heart problems, especially when used with certain chemotherapeutics.

Patients are closely monitored during treatment to manage these effects promptly and adjust therapy as needed.

The Bottom Line

Monoclonal antibodies have revolutionized cancer treatment by offering precision-targeted approaches that improve patient outcomes while minimizing collateral damage to healthy tissues. 

By directly targeting cancer cells or improving immune responses, mAbs have become indispensable tools in the fight against a wide range of malignancies.

If you want to use mAbs for your research related to cancer, make sure you find a reliable supplier that provides monoclonal antibodies for sale of high quality to support your research.