Immunotherapy has emerged as one of the most promising and transformative approaches in modern cancer treatment. In this blog, we will explore what immunotherapy is, its different types, how it works, and its impact on the fight against cancer.
What is Immunotherapy?
Immunotherapy is a type of treatment that uses or modifies the body’s immune system to help fight diseases. The immune system is the body’s natural defense mechanism against illness, using cells, tissues, and organs to identify and fight off harmful invaders, including bacteria, viruses and abnormal cells. Immunotherapies can be used to suppress an overactive immune response, as seen in conditions like rheumatoid arthritis and multiple sclerosis, or to enhance the immune system’s natural defenses, such as mRNA vaccines.
What is Immunotherapy for Cancer?
Though immunotherapy continues to expand into other areas of medicine, its most significant impact has been in cancer therapy. Immunotherapy utilizes the body’s immune system to fight cancer cells. It works by boosting or modifying the immune system to help it recognize and destroy cancerous cells more effectively, as opposed to traditional cancer treatments, which target cancer cells directly. By harnessing the power of the immune system, immunotherapy offers a more targeted, effective, and a potentially less toxic option compared to traditional treatments like chemotherapy and radiation.
Immunotherapy was first explored in the early 20th century, but it wasn’t until advancements in medical research over recent decades that immunotherapy gained traction as a viable treatment option for various types of cancer.
How Does Immunotherapy Work?
The immune system is a complex network of cells, tissues, and organs that work together to protect the body from harmful invaders, including bacteria, viruses, and abnormal cells. Unfortunately, in the case of cancer, some tumor cells can develop mechanisms to evade immune detection, preventing immune cells from recognizing and attacking them.
Immunotherapy works by overcoming these mechanisms and retraining the immune system to identify and destroy cancer cells. This can be done in several ways:
- Boosting the Immune System: Some forms of immunotherapy work by stimulating the immune system, encouraging it to attack cancer cells more aggressively.
- Reprogramming the Immune System: Others help the immune system recognize cancer cells by either removing the suppressive signals or by enhancing the ability of immune cells to target tumors.
- Direct Attack on Cancer Cells: Some immunotherapies, such as monoclonal antibodies, can attach to cancer cells directly and trigger a response that leads to their destruction.
Types of Immunotherapies for Cancer Treatment
There are several types of cancer immunotherapies, each working in different ways to enhance the immune system’s ability to target and destroy cancer cells, including:
1. Monoclonal Antibodies
Monoclonal antibodies are molecules engineered in a lab to mimic the immune system’s ability to fight off harmful pathogens. They can be used to target cancer cells directly, mark them for destruction, or inhibit the cancer cells’ ability to grow and spread. Some monoclonal antibodies work by attaching themselves to specific proteins on cancer cells, while others may act as immune checkpoint inhibitors, helping the immune system overcome the cancer’s defenses.
2. Immune Checkpoint Inhibitors
The immune system contains T cells that are built with different proteins that enable the cells to identify if the immune system needs to respond to a bacteria or virus the cells encounter. If the proteins signal the T cells to attack, this is called an immune response. These proteins are essentially the on and off switches for T cells and are referred to as immune checkpoints.
Some cancer cells contain similar proteins which allows them to use these checkpoints to escape detection by the immune system. Checkpoint inhibitors are drugs that were developed to block these checkpoints, ensuring that the immune response cannot be switched off and the T cells are able to recognize and fight off cancer cells.
3. Cancer Vaccines
The FDA has approved vaccines for cancer prevention, such as the HPV and Hepatitis B vaccines, and therapeutic vaccines, like sipuleucel-T, used to treat prostate cancer. The latter is a newer category of cancer vaccines that treat existing cancer by stimulating the immune system to attack cancer cells. Therapeutic vaccines are typically made from tumor proteins, which prompt the body to recognize and destroy cells that contain these markers while preventative vaccines are designed to attack viruses that can increase the likelihood of getting cancer later.
4. Adoptive Cell Transfer (ACT)
ACT modifies the patient’s own immune cells so they can more effectively fight cancer. The cells are harvested by using IV catheters to draw blood, the T cells are isolated and removed, and then the blood—without the T cells—is reinfused into the patient. The T cells are then enhanced in a laboratory to target and fight cancer cells more effectively, then reintroduced into the patient’s body. One of the most well-known examples of this type of immunotherapy is CAR T cell therapy, used to treat hematologic malignancies like certain types of leukemias and lymphomas, which involves harvested T cells being modified with a chimeric antigen receptor (CAR), that enhances the cells abilities to attach to cancer cells with that specific antigen.
5. Cytokine Therapy
As explained previously, T cells contain proteins that function as on and off switches for immune responses, and immune check point inhibitors work by blocking those proteins in order to prevent the T cells from being turned off prematurely by cancer cells. Cytokines, such as interleukins and interferons, function as signaling molecules rather than structural proteins. They transmit signals to immune cells, including T cells, directing them to activate and coordinate a targeted immune response. Unlike immune checkpoint inhibitors, which prevent T cells from being turned off, cytokine therapy enhances the targeted immune response by amplifying T-cell activation and coordination, strengthening their attack on cancer cells.
Advantages of Immunotherapy
Immunotherapy offers several distinct advantages over traditional cancer treatments like chemotherapy and radiation. One of the primary benefits is its ability to target cancer cells more precisely. While chemotherapy and radiation can damage both cancerous and healthy cells, leading to side effects like fatigue, hair loss, and nausea, immunotherapy generally has fewer and less severe side effects. For example, immune checkpoint inhibitors like pembrolizumab (Keytruda) and nivolumab (Opdivo) specifically restore T-cell activity against cancer cells, minimizing damage to normal tissue.
Additionally, immunotherapy also has a higher potential to provide long-lasting effects. Some treatments, such as CAR T cell therapy, have led to durable remissions in acute lymphoblastic leukemia, large B-cell lymphoma, and others. In these cases, patients may remain cancer-free for years after treatment without repeated interventions.
Another advantage of immunotherapy for cancer is its versatility when combined with other treatments. For example, combining immune checkpoint inhibitors with a more traditional cancer treatment, such as chemotherapy, has improved survival rates in advanced non-small cell lung cancer. These combinations have been shown to improve outcomes for some patients, particularly for patient’s whose cancer has advanced or become resistant to other forms of treatment.
The Challenges and Future of Immunotherapy
While immunotherapy has revolutionized cancer treatment, it is not without its challenges. One of the biggest challenges of immunotherapy is that not all patients respond to immunotherapy, and researchers are still trying to understand why some tumors are more resistant than others. Additionally, the high cost of immunotherapy drugs can be a barrier for many patients, although ongoing advancements in the field may help reduce costs in the future.
While side effects from immunotherapy are possible, they are generally less severe compared to traditional treatments like chemotherapy and radiation. These side effects are often related to the immune system becoming overactive, which can lead to inflammation in healthy organs and tissues, such as colitis or pneumonitis. Managing these side effects requires careful monitoring and may involve additional medications to suppress those immune responses.
The future of immunotherapy for cancer is promising, with ongoing research focusing on improving its effectiveness, expanding its use to a broader range of cancers, and developing biomarkers to better predict which patients will benefit the most. For example, researchers are exploring novel therapies like bispecific T-cell engagers (BiTEs), which are able to redirect T cells to target cancer cells more effectively, and next-generation CAR T cell therapies designed to combat solid tumors.
While cancer immunotherapy is still evolving and poses certain challenges, its impact on the cancer treatment landscape has already been profound. With ongoing advancements in research, immunotherapy will continue to evolve and become an integral part of cancer care, providing more patients with effective and long-lasting treatment options.
For information about Allucent’s expertise in Immunotherapy and other types of cancer treatment, visit Oncology & Hematology. To learn more about CAR-T therapy, read our blog, CAR T-Cell Therapy Challenges to Development & Approval.
About the Allucent Editorial Team
The Allucent Editorial Team is composed of experienced professionals in drug development, spanning preclinical research, clinical trials, regulatory strategy, and scientific communications. As part of Allucent’s content team, we collaborate with subject matter experts to deliver insightful, industry-leading perspectives on emerging trends and scientific advancements. Our goal is to provide biotech innovators with clear, informative content that supports strategic decision-making in a complex development landscape.
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