Huge strides have been made in treating children with cancer. Standard cancer treatments, including surgery and radiation therapy, are often able to bring about a cure. But not always. Sometimes, these treatments can also cause health effects that stay with pediatric cancer patients throughout their lives. This is where immunotherapy comes in.

Immunotherapy uses the body’s own immune system to attack cancer cells. Researchers have been working for decades to develop this alternative method of cancer treatment. Immune therapy is now standard of care for treating several adult advanced cancers, and has become an important type of treatment for some childhood acute leukemias. Immunotherapy has the potential to enhance or even replace current options in many diseases.

“There is a great deal of promise in using immunotherapies to treat pediatric cancers as highlighted by successes in leukemia, lymphoma and, to some extent, neuroblastoma,” says Juan Vasquez, MD, a Yale Medicine pediatric hematologist and medical oncologist in the Pediatric Hematology & Oncology Program. “However, there is more research that needs to be done in both the development of novel immune treatments and the clinical testing of existing drugs.”

Each of our bodies has its own military force, called the immune system, which fights against infection and other diseases. When the immune system detects a foreign substance, it triggers an immune response to take it down. 

But for some reason, the body doesn’t always recognize cancer cells as foreign, which is why cancer is able to survive and spread. Immunotherapy works to solve this problem by triggering and boosting the body’s immune response against cancer. Researchers have developed various methods to achieve this goal. Some types of immunotherapy activate the existing immune response, while others mimic immune cells to achieve the same effect as the immune response.

Immunotherapies are being developed to treat many different conditions. The major types of cancer immunotherapy include the following:

Monoclonal antibodies: One way the immune system attacks invaders in the body is by producing proteins called antibodies. Monoclonal antibodies have been designed by scientists to specifically target cancer cells. These man-made antibodies can be delivered to patients through an injection.

Immune checkpoint inhibitors: The immune system has certain checkpoints that serve to prevent over-activation of the immune system, which could lead to severe illness and attacks on normal tissues. Cancer cells are often able to use these checkpoints to suppress the immune cells that are recognizing and attempting to kill the cancer. If the checkpoint gets blocked by certain monoclonal antibodies, the immune response is no longer held back; immune cells can attack cancer cells in full force.

Cancer vaccines: Unlike the vaccines we receive to prevent certain diseases from starting, these vaccines help the immune system to recognize and attack an already existing disease. Vaccines for cancer treatment can be made by altering the patient’s own tumor cells in the lab to make them more likely to be recognized by the immune system. More modern vaccines are using the unique mutated proteins from the cancer cells, in combination with powerful immune stimulators, to produce immune responses that attack only the cancer cells. Like other vaccines, they’re delivered to patients through an injection.

Adoptive cell transfer: T cells are a type of immune cell that attacks cells that have mutations, such as cancer cells. The doctor can remove a sample of the patient’s own T cells and modify them in the lab so that they’re better able to recognize and destroy cancer cells. When the modified cells are put back into the patient’s body, they continue growing and attack the cancer. 

Patients may receive other immunotherapies that boost the immune system in general, rather than targeting cancer cells specifically. 

The U.S. Food and Drug Administration has approved some immunotherapies specifically for children; immunotherapies for children are usually adapted from versions used in adult patients. For example, monoclonal antibodies have been approved for the treatment of childhood leukemia and lymphoma. Immunotherapy can be given alone or alongside other standard treatments. Although every treatment has possible side effects, so far, the effects of immunotherapy appear to be less severe than the effects of chemotherapy. 

Several other immunotherapies are still experimental. To receive them, the patient will need to be enrolled in a clinical trial by a doctor at a major hospital. Because these treatments are new, the long-term effects of immunotherapies are still being explored.

“As part of the Children’s Oncology Group, a research group supported by the National Cancer Institute, Yale is a participating site in ongoing clinical trials testing a variety of immunotherapies for the treatment of pediatric cancers,” say Dr. Vasquez. “Additionally, Yale has open early-phase immunotherapy trials through our collaboration with industry partners.” 

There are also exciting basic and translational science investigations taking place aimed at identifying and developing novel immunotherapy treatments. These research efforts build on collaborations between Yale oncologists and world-renowned immunology researchers at Yale, he says.