Immunotherapy is an innovative cancer treatment that uses certain components of a patient’s immune system to fight his or her cancer. This can be done by stimulating the patient’s immune system to target cancer cells or by introducing man-made immune system proteins and other elements into the patient’s body. Immunotherapy has proven more successful in treating certain types of cancer than others. However, new forms of immunotherapy are being researched every day and will continue to impact the way we approach cancer treatment moving forward.
How does immunotherapy work?
There are several types of immunotherapy treatments; some boost the patient’s immune system in a general way while others train the immune system to target cancer cells specifically. Immune cells travel throughout the body via the lymphatic system to fight off infection by attacking germ cells. Because germ cells contain proteins that are not normally found in the body, the immune system is able to identify them as invaders. Cancer cells also contain unfamiliar substances, but because cancer usually develops gradually as healthy cells undergo abnormal changes, the immune system is often able to adapt to the changes and does not always recognize the cancerous cells as being foreign.
Types of immunotherapy
With this in mind, researchers are studying immunotherapy as a way to boost the immune system and help it identify and target cancerous cells. Several types of immunotherapy can be used for treating cancer, including:
- Adoptive cell transfer – T-cells are removed from the patient, multiplied in a lab and then reinfused to the patient.
- Immune checkpoint inhibitors – These drugs help a patient’s immune system recognize and attack cancer cells.
- Cytokines – Man-made cytokines, a group of proteins found naturally in the body, are used to treat cancer.
- Monoclonal antibodies – Man-made monoclonal antibodies are administered to a patient to attack his or her cancer cells.
- Cancer vaccines – Vaccines are injected into the body to stimulate the immune system, essentially training it to work against certain diseases, such as cancer.
- Oncolytic viruses – Viruses are used to destroy cancer cells without harming healthy cells.
- Other immunotherapies – These treatments boost a patient’s immune system in a general way to enhance its ability to fight cancer cells.
Monoclonal antibody therapy
Monoclonal antibody treatment involves administering monoclonal antibodies to a patient to help destroy their cancer cells. An antibody is a Y-shaped protein that binds to a foreign invader (antigen), signaling to other immune cells that they need to attack it (in some cases, the antibody will destroy the invader on its own). A monoclonal antibody, in turn, is a man-made version of an antibody that’s produced in a laboratory.
During cancer-related monoclonal antibody infusion, monoclonal antibodies bind to both cancer cells and immune system cells, either marking the cancer cells so that the immune system can attack them or bringing the two types of cells close enough together that the immune system can destroy the malignancy.
As was mentioned above, cytokine therapy involves using man-made cytokines to treat cancer. A cytokine is a type of protein that helps control the growth and activity of immune system cells and blood cells. With regard to cancer treatment, specifically, cytokines are able to send signals that help destroy cancer cells and enable normal cells to live longer. Other types of cytokines can be used to either prevent or manage the side effects associated with chemotherapy, thereby also assisting in the fight against cancer.
Oncolytic virus therapy
Before getting into the application of oncolytic viruses in cancer treatment, it may be helpful to explain what an oncolytic virus is. A virus, in general, is an infectious agent that enters a cell, uses the cell to make copies of itself, and then spreads those copies to nearby cells to repeat the process. An oncolytic virus is a type of virus—either natural or man-made—that’s able to destroy cancer cells without harming normal cells. The history of oncolytic viruses is lengthy—as early as the late 1800s, physicians started noticing that cancer patients would sometimes go into remission (if only temporarily) after contracting a viral infection. This realization prompted the study of integrating oncolytic viruses in combination with cancer immunotherapy.
So, how does oncolytic virus therapy work? Oncolytic virus immunotherapy typically involves injecting a genetically modified virus into a tumor. Not only can this directly kill the cancer cells, but it may also trigger a response from the body’s own immune system. How do oncolytic viruses target cancer cells? Once injected into a tumor, an oncolytic virus infects the cancer cells, causing them to break down and die. When the cancer cells burst, they release substances—for instance, tumor antigens—that enable the immune system to recognize the malignancy. This recognition, in turn, can prompt a local or systemic immune response, whereby the immune system attacks any remaining cancer cells.
One of the primary benefits of oncolytic virus therapy is that the virus generally does not harm healthy cells. Potential side effects of using oncolytic virus therapy for cancer treatment will depend on a number of different factors, such as the type of virus being injected, the type of cancer being targeted, the location of the tumor and the patient’s overall health.
Are there any FDA-approved oncolytic viruses? As of May 2022, there is only one - on October 27, 2015, the FDA approved talimogene laherparepvec (T-VEC), which is a genetically modified form of the herpes simplex virus, to treat certain patients with metastatic melanoma that cannot be surgically removed. However, numerous other types of oncolytic viruses (as well as certain strains of bacteria) are currently being tested in oncolytic virus clinical trials as potential cancer treatment options. Moffitt Cancer Center, for instance, is collaborating with the biotechnology company Memgen to study whether the oncolytic virus MEM-288 could potentially be used to treat lung cancer.
Researchers are also examining other ways to administer oncolytic virus therapies. While oncolytic viruses for cancer immunotherapy have traditionally been delivered via a direct injection into the tumor being targeted, scientists are now exploring the potential effectiveness of instead introducing an oncolytic virus through an intravenous injection.
How is immunotherapy administered?
Immunotherapies may be administered either into a vein (intravenously), by an injection, under the skin (subcutaneously) or into a muscle (intramuscularly). Certain types of immunotherapy may be delivered directly to the body cavity where the tumor is located.
What cancers can be treated by immunotherapy?
Each patient is evaluated on a case-by-case basis to determine if immunotherapy is right for him or her. That said, immunotherapy has proven to be a viable treatment option for a number of different cancers, including:
- Bladder cancer
- Brain cancer
- Breast cancer
- Cervical cancer
- Colorectal cancer
- Esophageal cancer
- Head and neck cancers
- Kidney cancer
- Liver cancer
- Lung cancer
- Multiple myeloma
- Ovarian cancer
- Pancreatic cancer
- Prostate cancer
- Skin cancer
- Stomach cancer
Side effects of immunotherapy
Immunotherapy, like other cancer treatments, may cause a number of side effects. The specific side effects a person experiences will depend on the specific type of immunotherapy he or she had. That said, common side effects of immunotherapy are similar to flu-like symptoms and may include:
- Shortness of breath
- Nausea or vomiting
- Decreased appetite
Much less commonly, a number of severe side effects may also occur up to two years following immunotherapy. It is important for all immunotherapy patients to be aware of the severe side effects of immunotherapy and to contact their doctor right away if they occur. Some severe side effects and their symptoms may include:
- Inflammation of the liver (hepatitis) – Jaundice, severe nausea or vomiting and tea-colored urine
- Inflammation of the colon (colitis) – Bloody or black stools, diarrhea and severe stomach pain
- Inflammation of the lung (pneumonitis) – Chest pain, shortness of breath and coughing
- Inflammation of the brain (meningitis, neuropathy or encephalitis) – Confusion, hallucinations, memory problems, sleepiness and headache
- Kidney problems – Change in urine color or amount, blood in the urine, loss of appetite and swelling in the ankles
- Eye problems – Blurry or double vision, eye redness and eye pain
Immunotherapy clinical trials
As with other forms of cancer treatment, immunotherapy clinical trials are currently being conducted to improve treatment for patients with many different types of cancer. Patients are encouraged to participate in appropriate immunotherapy clinical trials for several reasons. To begin, patients who participate in a clinical trial can be among the first to benefit from novel therapies before those options are made widely available. Additionally, immunotherapy clinical trials may provide new hope for patients who have not had success with traditional forms of treatment.
Immunotherapy treatment at Moffitt Cancer Center
At Moffitt Cancer Center, our scientists and clinicians are continually developing novel cellular immunotherapy treatments for various types of cancer, and we continue to gain ground in understanding and treating all forms of this complex disease. As we discover promising new treatment options through our laboratory breakthroughs, we are committed to bringing those treatments to clinical trials as quickly as possible so that our patients can benefit from them. Additionally, our multispecialty team of experts provides outstanding clinical care for patients who are receiving immunotherapies, constantly reviewing their responses to treatment and updating their treatment plans as needed. Moffitt’s leadership is also continually recruiting outstanding new faculty members to further develop our cellular immunotherapy program.
If you'd like to learn more about immunotherapy, call 1-888-663-3488 or complete a new patient registration form online to request an appointment with an expert at Moffitt. We’re providing each new patient with rapid access to a cancer expert within just one day, a faster turnaround time than that offered by any other cancer hospital across the country.
National Cancer Institute: Immunotherapy to Treat Cancer
National Cancer Institute: Monoclonal Antibodies
National Cancer Institute: FDA Approves Talimogene Laherparepvec to Treat Metastatic Melanoma
National Cancer Institute: Oncolytic Virus Therapy
American Cancer Society: Cytokines and Their Side Effects
Cancer Research Institute: Oncolytic Virus Therapy
Charles River: Oncolytic Viruses
Medical NewsToday: What to know about antibodies