Immunotherapy is currently one of the most discussed topics these days in cancer research. Anyone who tracks cancer news is bound to encounter dozens of headlines on the subject. In fact, immunotherapy is one of the most exciting areas of new discoveries and treatments for many types of cancer. Understanding how the immune system works is changing the way we think about and treat this disease. In this blog post, we’ll be giving you a brief introduction to what immunotherapy is, and if it could be the right treatment method for you.
Let’s begin with the basics:
What is immunotherapy?
Immunotherapy is a treatment that uses the body’s own natural defenses to fight cancer cells (aka your immune system). Immunotherapy drugs either boost your immune response or enable your immune system to more readily recognize and fight tumors.
What are some names for this field?
The field that produces immunotherapy treatments is referred to as immuno-oncology or tumor immunology.
What is the immune system?
Your immune system is a network of cells, tissues, and organs that all work together to recognize and destroy foreign invaders such as bacteria, viruses, or abnormal or unhealthy cells. The most important function of the immune system is knowing the difference between self and non-self. Self means your own body tissues, while non-self refers to any foreign invader. Normally, your immune system will attack anything that it identifies as non-self.
How can cancer trick your immune system?
Although cancer cells eventually grow to become different from normal cells, they still develop from our own cells. Sometimes our immune system is able to detect the mutations and changes in cancer cells and respond but other times, the cancer cells slip past our defense system, or even inhibit the immune system.
What does immunotherapy do to the immune system?
To strengthen your immune system for the task of identifying and attaching cancer cells, scientists have designed drugs that boost your white blood cells (T cells). These are the cells that make up your immune system and are the ones that recognize and kill cancer cells in your body.
Do all immunotherapy drugs focus on strengthening white blood cells?
In general, early immunotherapy drugs worked by boosting the body’s immune system through white blood cell stimulation. However, recent research has found other methods of strengthening your immune system. For example, researchers have found several proteins that live on the surface of T cells that act like brakes, or checkpoints, in the process of cancer cell defense. Blocking proteins that prevent T cells from attacking cancer cells could be a viable method of defeating cancer.
What are some notable examples of these “checkpoints”?
CTLA-4 is a checkpoint discovered in 1996 that a scientist named Jim Allison proposed to block. Dr. Allison’s findings led to the development and approval of a drug called Ipilimumab that inhibits this specific immune checkpoint. You can learn more about IIpilimumab here on the National Cancer Institute’s website.
Another checkpoint example is called PD-1, which was discovered in 2000. Several drugs have been formulated to turn off the PD-1 checkpoint for multiple types of cancer cells, allowing T cells to effectively attack tumors. You can learn more about PD-1 here.
So overall, what categories of immunotherapy drugs are there?
Immunotherapy drugs fall into two main categories: targeted therapies and general immunotherapies.
Targeted immunotherapies, according to the National Cancer Institute, are therapies that block the growth and spread of cancer by interfering with specific molecules that are involved in the growth, progression and spread of cancer. Targeted therapies act on specific molecular targets whereas standard chemotherapies act on all rapidly dividing normal and cancerous cells. Some common types of targeted immunotherapies are monoclonal antibodies and cancer vaccines.
- Monoclonal antibodies are designed to identify specific abnormalities on the surface of cancer cells. The antibodies attach themselves to these abnormalities, making themselves a clear target for the immune system.
- Cancer vaccines help the body recognize cancer cells and stimulate the immune system to destroy them. Some vaccines contain cancer cells harvested from patients’ tumors. Others contain proteins designed to attach themselves to cancer cells.
General immunotherapies are non-specific treatments that do not affect the cancer itself. These immunotherapies work on proteins called cytokines that send signals to stimulate the body’s immune system to fight cancer cells. Common types of general immunotherapies are interleukins, interferons, and colony stimulating factors also referred to as CSFs.
- Interleukins control the growth and activity of T cells. More than a dozen of these proteins have been identified. Interleukin-2 (IL-2), for example, is used to treat kidney cancers and melanomas that have metastasized to other regions of the body.
- Interferons are a group of three proteins released by T cells in reaction to invading organisms. Interferons increase the immune system’s reaction to cancer cells. Interferon alpha (IFN-afa), for example, is currently being used to treat melanoma, kidney cancer, and certain types of leukemia and lymphoma.
- CSFs strengthen the immune system by stimulating the production of white blood cells in the bone marrow. CSF therapies are used to help elevate low white blood cell counts after chemotherapy.
It’s easy to see why immunotherapy is such an exciting field to be in right now; it’s changing the way that we see our immune system and how it interacts with cancer. As researchers learn more about this relationship, they will be able to apply their knowledge to an increasing number of treatment plans.
Let’s move onto how immunotherapy can affect you:
What are some side effects of immunotherapy treatments?
Immunotherapy, regardless of the approach used, will have side effects like any other treatment plan. However, these side effects may vary greatly from those experienced through chemotherapy, and will be different from person to person depending on their treatment type.
In general, the most common side effects of immunotherapy are:
- Flu-like symptoms
- Drops in blood pressure
Less common side effects are:
- Colitis or other gastrointestinal problems
- Thyroid problems
- Lung problems
At this time, little is known about what, if any, long-term effects immunotherapy might have. As more and more people with advanced diseases survive for longer periods of time, this will become an important area to study and understand.
The most important thing to remember is that if you are taking any form of immunotherapy, it is critical to communicate anything you’re feeling with your doctor or treatment team. The side effects of immunotherapy can be managed effectively once they’ve been identified.
How do I know if my immunotherapy is working?
Unlike chemotherapy or radiation therapy treatments, the effects of immunotherapy drugs can take longer periods of time to work. Although the waiting time to see if the treatment is working can be long and very difficult for patients, there is a genuine excitement about the promise of immunotherapy. For many types of cancer, even those that have traditionally been very hard to treat, immunotherapy responses have been promising and response rates have been higher than those from other types of therapy.
Currently, under what cases or scenarios is immunotherapy being used?
Most people today who receive immunotherapy have cancers that are very advanced. Their cancers have either recurred and spread after primary treatment, or they were diagnosed with advanced stage cancers.
Given the widespread interest and excitement throughout the cancer community about the potential of immunotherapy, why is it not being used on a larger scale?
One reason is that some people cannot receive immunotherapy. These individuals often have problems that make it impossible to take these drugs safely.
The larger reason is that immunotherapy is still a rather new field. Even though it has great potential, we still don’t know enough about it. As a result, immunotherapy is still given in specialized cancer centers and mostly as a part of clinical trials. As the field of immunotherapy moves forward, researchers hope to begin new clinical trials with people who are at a high risk for having their cancers recur or spread.
What should I do if I’m interested in immunotherapy?
If you are interested in immunotherapy, your best plan is to talk about your options with your doctor and treatment team.
We hope this blog post helped you learn a little bit about immunotherapy, and we’d love to hear from you about more blog post topics!