Immunotherapy and Leukemia and Lymphoma
The type of immunotherapy used depends on the exact subtype of blood cancer being treated. Many immunotherapy treatment options are still only available through clinical trials. If you are interested in immunotherapy, talk with your doctor about your options, including a clinical trial.
Types of Immunotherapy
Abnormalities or differences between normal and cancerous cells often present themselves as “antigens” on the surface of the cancer cells. They can be attacked with monoclonal antibodies, drugs produced in the laboratory that act like the natural antibodies in our immune system.
The monoclonal antibody, rituximab for example, recognizes the CD20 antigen on the surface of B lymphocytes and destroys those cells. Rituximab was the first monoclonal antibody shown to be effective in treating cancers that arise in B-cells and remains an important front line treatment for these leukemias and lymphoma.
But it is now one of an increasing number of similar drugs targeting specific antigens in a wide variety of leukemias and lymphomas. In some cases, these drugs are combined with chemotherapy agents or radioactive particles to deliver treatment directly to the cancer cell.
Adoptive Cell Therapies
Another approach to immunotherapy involves engineering a patient’s own T cells to recognize and attack tumors. This is known as adoptive cell therapy. To date, adoptive cell therapy has been available only in clinical trials in highly specialized cancer centers.
A growing number of studies have generated promising results in both pediatric and adult patients with acute lymphoblastic leukemia (ALL), adults with chronic lymphocytic leukemia (CLL) and lymphoma.
Therapeutic cancer vaccines work on roughly the same principle—to teach the immune system to recognize an individual's tumor and attack it. The goal is to produce a treatment that will retain that "immunologic memory" and continue destroying the cancer cells for a long period of time. To do that, it is necessary to identify a specific characteristic of the abnormal cell that will trigger the immune response.
Leukemia and lymphoma are potentially excellent subjects for therapeutic cancer vaccines because they often result from or are characterized by genetic mutations that provide targets for vaccines.
One excellent example of this is the Philadelphia chromosome, an abnormality found in 95% of people with chronic myeloid leukemia (CML). The immune system is able to recognize this mutation and attack it, although the response is not sufficient to kill all the cancer cells.
There are now trials that seek to boost both the natural immune response to the CML cells and promote an immune memory using a vaccine.
Other trials using cancer vaccines are underway to treat type of leukemia, such as acute myeloid leukemia (AML). In many instances, therapeutic cancer vaccines don't eliminate the blood cancer, they keep it in check or suppress its growth.
Side Effects of Immunotherapy
Side effects include fevers, flu-like symptoms, drops in blood pressure, rashes and fatigue. Some people also have colitis and damage to their thyroids or other parts of the endocrine system.
These side effects result from the increased activity of the immune system. While the goal is to kill the cancer cells, the boost in the immune response can affect normal cells as well.
For many people with cancer, the side effects of immunotherapy are relatively mild and often temporary. More serious problems are usually controlled with drugs, including steroids and others that reduce the inflammatory response.
It is very important to let your treatment team know right away if you develop any symptoms after you begin immunotherapy or at any time during your treatment.
The Future of Immunotherapy for Leukemia and Lymphoma
The field of immuno-oncology for cancers that arise in the blood and lymphatic systems is still in its very early stages. Researchers are finding new targets for more types of blood cancer and learning more about why some people respond so well, and others do not.
As the understanding of the dynamic relationship between cancer cells and the immune system deepens, there will be increasing opportunities to develop new therapies using that knowledge to improve the outcomes for people with many different types of leukemia and lymphoma.