How Cancer Vaccine Fights Tumors Throughout the Body
After a cancer diagnosis, people with cancer and their families have to make a number of decisions about treatment. These decisions are complicated by feelings of anxiety, unfamiliar words, and a sense of urgency. But do you know Cancer “vaccine” that’s injected directly into a single tumor can trigger the immune system to attack cancer cells throughout the body, a small study suggests.
The vaccines, also called vaccinations, are medicines that help the body fight disease. They can train the immune system to recognize and destroy harmful substances.
There are 2 types of cancer vaccines:
- Prevention vaccines
- Treatment vaccines
The researchers say that the experimental therapy essentially turns tumors into “cancer vaccine factories,” where immune cells learn to recognize the cancer before seeking it out and destroying it in other parts of the body. “[We’re] seeing tumors all throughout the body melting away” after injecting just one tumor, said lead study author Dr. Joshua Brody, director of the Lymphoma Immunotherapy Program at the Icahn School of Medicine at Mount Sinai in New York.
Still, the research, published in the journal Nature Medicine, is very preliminary. The therapy has only been tested in 11 patients with non-Hodgkin’s lymphoma (a cancer of immune system cells), and not all of these patients responded to the treatment. But some patients did have remission for relatively long periods, and the results were promising enough that the therapy is now also being tested in patients with breast and head and neck cancers, the authors said.
The two therapies “are remarkably synergistic.” So far, the researchers have only tested the combined therapies in mice, but they are optimistic that the combined therapies could benefit cancer patients, particularly those that aren’t getting much benefit from current immunotherapy treatments.
To be clear, the new treatment is not technically a vaccine — a term used for substances that provide long-lasting immunity against disease. (Still, the term “cancer vaccine” can be used to refer to therapies that train the immune system to fight cancer, according to the American Cancer Society.)
There are 2 types of cancer prevention vaccines approved by the U.S. Food and Drug Administration (FDA):
- HPV vaccine. The vaccine protects against the human papillomavirus(HPV). The FDA has approved HPV vaccines to prevent:
- Cervical, vaginal, and vulvar cancer
- Anal cancer
- Genital warts
HPV can also cause other cancers the FDA has not approved the vaccine for, such as oral cancer.
- Hepatitis B vaccine.This vaccine prevents hepatitis B virus (HBV) infection. Long-lasting infection with HBV can cause liver cancer.
Cancer Treatment Vaccines
Cancer treatment vaccines, also called therapeutic vaccines, are a type of immuno therapy. The vaccines work to boost the body’s natural defenses to fight a cancer. Doctors give treatment vaccines to people already diagnosed with cancer. The vaccines may:
- Prevent the cancer from coming back
- Destroy any cancer cells still in the body after other treatments have ended
- Stop a tumor from growing or spreading
The therapy has three steps
First, patients are given an injection that contains a small molecule that recruits immune cells, called dendritic cells, into the tumor. Dendritic cells act like generals in an army, telling the immune system “soldiers” — known as T cells — what to do.
Next, patients are given a low dose of radiotherapy, which kills a few tumor cells so that they spill out “antigens,” or proteins, that the immune system can learn to recognize, said the researcher. Dendritic cells then take up these antigens and show them to the T cells.
Then, patients are given a second injection that contains a molecule that activates the dendritic cells. In the new study, many of the 11 lymphoma patients saw a regression of their tumors that lasted for months to years. But several patients didn’t benefit from the therapy.
The researchers were also interested to see how their therapy worked with checkpoint blockade drugs, which essentially take the “brakes” off T cells so they better attack cancer cells. While this therapy can work well for some types of cancer.
When the researchers gave checkpoint blockade drugs to mice with non-Hodgkin’s lymphoma, the treatment, not surprisingly, had no effect. But when they gave it in combination with their vaccine, about 75% of the mice went into long-term remission.
The authors think “this could be … effective for many cancer types that are so far not benefiting much from cancer immunotherapy,” Brody said.
How A Cancer Treatment Vaccine Works
This leaves the immune system with a “memory” that helps it respond to those antigens in the future.
Cancer treatment vaccines boost the immune system’s ability to recognize and destroy antigens. Antigens are substances on the surface of cells that are not normally part of the body. The immune system attacks the antigens, usually getting rid of them.
Often, cancer cells have certain molecules called cancer-specific antigens on their surface that healthy cells do not have. When these molecules are given to a person, the molecules act as antigens. They stimulate the immune system to recognize and destroy cancer cells that have these molecules on their surface..
Some cancer vaccines are made for individual patients. These types of vaccines are produced from the person’s tumor sample. This means that surgery is needed to get a large enough sample of the tumor to create the vaccine.
Most cancer treatment vaccines are only available through clinical trials, which are research studies involving volunteers. But in 2010, the FDA approved sipuleucel-T (Provenge) for men with metastatic prostate cancer. Metastatic means the cancer has spread from where it began to other parts of the body. Sipuleucel-T is customized for each person through a series of steps.
- First, white blood cells are removed from the person’s blood. White blood cells help the body fight infections and diseases.
- Then the white blood cells are modified in a laboratory to recognize and target prostate cancer cells.
- Next the modified cells are put back into the person through a vein. This is similar to a blood transfusion. The modified cells teach the immune system to find and destroy prostate cancer cells.
Thought from the research, some experts say the research shows promising results, but it’s too early to tell if it’s going to be beneficial in humans.
“It is good to remember that the compound has a long path ahead before it is available to patients and that positive results in mice do not always translate to positive results in humans,” David Saxner, a principal at the life science consulting firm Longfellow Associates who previously has worked in evaluating oncology clinical trials.
Decisions about cancer treatment are personal, and you need to feel comfortable with your choices. But many people do not know where to start.
Individual treatment plans depend on the type of cancer and stage. So you should learn as much as you can about your specific diagnosis. You may want to ask your health care team questions about the disease. But be careful when doing research online. Many sites can be frightening, inaccurate, or misleading. Your health care team can suggest trustworthy websites. If you come across unfamiliar words while researching online, ask your health care team for an explanation.