June is Cancer Immunotherapy Month. While some of the earliest iterations of immunotherapy can be traced back centuries, this relatively new form of cancer treatment received its first Food and Drug Administration (FDA) approval in 2011 after decades of research.
Ipilimumab, a type of immunotherapy known as a checkpoint inhibitor, was the first immunotherapy treatment approved by the FDA in 2011. This would only be the start to a group of treatments that has now expanded to more than 20 FDA-approved treatments in three main categories, with many more on the horizon. To mark this remarkable achievement, the Cancer Research Institute launched Cancer Immunotherapy Month in June of 2013.
Immunotherapy is a classification of cancer treatment that harnesses the power of the immune system, through multiple different strategies, to help find and destroy cancer cells. It can be used alone or in combination with other more well-known forms of treatment, like chemotherapy and radiation. Immunotherapy has even become the standard of care for certain cancers and could likely become the backbone of treatment for all or most cancer types in the near future.
Oncologists decide which type of immunotherapy is best for each individual patient depending on the type, size, location, and spread of the cancer. At this moment, three general categories of immunotherapy are used with patients:
- Adoptive cell therapy: Also known as cellular immunotherapy, this is a form of treatment that uses the cells we already have in our immune system to fight cancer. There are a few different ways that this can be done. One way is by isolating the patient’s own cells that have been exposed to their cancerous cells, multiplying them in the lab, and then putting them back in the patient. This larger number of cells increases the chance that they will find and eliminate cancer cells. Another method is to isolate and then genetically engineer the patient’s immune cells to make them better at fighting cancer.
- Immune checkpoint inhibitors: Immune checkpoints are normally used by the immune system to prevent an immune response from being too strong and destroying healthy cells in our body, instead of just the foreign cells. When the immune cells called T-cells find an unknown cell, they need a way to determine if it is good or bad. One of the ways they do this is by using proteins on the surface of the T-cell to bind with partner proteins on the unknown cell. If the unknown cell has the correct protein, it tells the T-cell not to destroy it. Unfortunately, many cancer cells have figured this out and now display the “don’t destroy me” proteins as a way to avoid the T-cells, stay alive, and spread throughout the body. Checkpoint inhibitors work by blocking proteins on the T-cells from binding with their partner proteins, which then allows the T-cell to destroy the cancer cell.
- Cancer vaccines: All vaccines work by training your immune system to identify dangerous cells, like cancer cells, so they can be eliminated. There are two types of cancer vaccines: preventative and therapeutic. Preventative cancer vaccines are used to fight against certain viruses that are known to cause cancer. Currently, the Hepatitis B vaccine and several HPV vaccines are the only options currently approved by the FDA for use in patients. By preventing someone from getting HPV and Hepatitis B, it can drastically reduce the chance a person will get cervical cancer or liver cancer, respectively. Therapeutic vaccines are used to treat a person who already has cancer. They work by training your immune system to locate specific cancer cells by exposing it to small amounts of molecules, called antigens, that are associated with a specific cancer. Your immune system then learns it should find and eliminate any cells with that antigen.
Does immunotherapy have side effects?
As with any sort of treatment, there is always the chance of experiencing side effects with immunotherapy. The most common side effects happen because the immune system becomes so active that it affects healthy cells and tissues, not just the cancer cells, and the severity can depend on many factors, including how healthy you were before treatment and what type of treatment you receive.
The most common side effects include: skin symptoms like a rash or itching, flu-like symptoms like fever and chills, and gastrointestinal symptoms like diarrhea. Other more severe side effects, like infusion reactions and autoimmune reactions, occur much less often.
Staying one step ahead with cancer research
As you can see, the overarching goal of immunotherapy is to help our immune system better identify and eliminate cancer cells. Cancer is always evolving and finding ways to avoid our immune system, so it takes continuous research to try to be one step ahead.
Despite the great strides made over the last few decades, there are still areas left to decipher, such as predicting the effectiveness of immunotherapy, tackling cancer’s resistance to immunotherapy, designing clinical research strategies to help determine immunotherapy effectiveness, and attempting to reduce their extremely high treatment costs so they can be more accessible to people who need them.
Progress in cancer immunotherapy research continues at an incredible pace, and researchers continue to explore new and exciting avenues to increase how many cancers can be treated with immunotherapy. The amount of combinations of immunotherapy with other immunotherapy options and also with other forms of treatment is vast and will no doubt change the future of cancer treatment so that even more patients can enjoy better health outcomes.