Targeted immunotherapy is a modern cancer treatment. It precisely identifies and attacks cancer cells based on their unique characteristics, or enhances the body’s immune system to eliminate cancerous growths. The goal is a more focused attack on the disease, potentially reducing harm to healthy cells.
How Targeted Immunotherapy Works
Targeted immunotherapy focuses on specific differences that allow cancer cells to survive and grow. The “targeted” aspect interferes with particular proteins, genes, or pathways within cancer cells crucial for their proliferation and survival. These targets include signals cancer cells use to communicate, grow, and divide, or mechanisms allowing tumors to form new blood vessels.
The “immunotherapy” component strengthens the body’s natural defenses, the immune system, to find and destroy cancer cells. Cancer cells often evade immune detection, but immunotherapy aims to overcome these strategies. By stimulating or modifying immune cells, these therapies help the body’s defenses recognize cancer as abnormal and launch an effective attack. This approach differs from traditional chemotherapy, which broadly attacks rapidly dividing cells, by offering a more precise and less damaging way to combat cancer.
Key Types of Targeted Immunotherapy
Immune checkpoint inhibitors are a category of targeted immunotherapy. These drugs “release the brakes” on the immune system, allowing immune cells, particularly T-cells, to more effectively recognize and attack cancer. Cancer cells exploit natural immune checkpoints, proteins that prevent immune responses from becoming too strong, to avoid destruction. By blocking these checkpoints, inhibitors like pembrolizumab or nivolumab enable the immune system to respond to cancer cells it previously ignored.
Chimeric Antigen Receptor (CAR) T-cell therapy is another type. This personalized treatment involves taking a patient’s T-cells, genetically modifying them in a laboratory. The modification equips these T-cells with new receptors, called CARs, that specifically recognize proteins on cancer cell surfaces. Once modified, these CAR T-cells are multiplied and infused back into the patient, where they can locate and destroy cancer cells. CAR T-cell therapy has shown success in treating certain blood cancers.
Monoclonal antibodies are also a form of targeted immunotherapy. These laboratory-made proteins mimic the body’s natural antibodies and attach to specific proteins found on cancer cells or immune cells. When they bind to targets, they can disrupt cancer growth signals, deliver toxic substances directly to cancer cells, or mark cancer cells for destruction by the immune system. Examples include antibodies that block growth signals, such as trastuzumab for HER2-positive breast cancer, or those that enhance immune responses.
What Cancers It Treats and Patient Eligibility
Targeted immunotherapy treats a growing number of cancer types. It has shown success in treating melanoma, certain lung cancers, kidney cancer, and specific lymphomas and leukemias. For instance, CAR T-cell therapy is an option for some children and adults with leukemia and certain adults with lymphoma.
Patient eligibility is determined by identifying specific molecular targets within their cancer. This often involves genetic testing or other diagnostic tests to analyze cancer cells for particular genes, proteins, or biomarkers. For example, some lung cancers have specific mutations responsive to certain targeted therapies, and identifying these mutations helps doctors select the most effective treatment. Not all cancers or patients are candidates, as a suitable target is a prerequisite for treatment.
Understanding and Managing Side Effects
While targeted immunotherapy offers precise treatment, it can still cause side effects, which often differ from those associated with traditional chemotherapy. Many of these adverse reactions stem from the immune system becoming overactivated and mistakenly attacking healthy tissues. This can lead to inflammation in various organs throughout the body.
Common side effects might include skin rashes, fatigue, diarrhea, or inflammation in the lungs, colon, or endocrine glands like the thyroid. Less common but more severe reactions can involve inflammation of the heart or kidneys. Close monitoring by healthcare providers is important to detect these immune-related adverse events early. Management strategies often involve using immunosuppressive medications, such as corticosteroids, to reduce the overactive immune response and alleviate symptoms.