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Allergy Shots: How Does Immunotherapy Work?
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Ralph Boccia M.D.
Traditional cancer therapies like chemotherapy and radiation therapy are notorious for their severe side effects. Newer "immunotherapies," which target cancer cells and leave other cells alone, are more tolerable. But how effective are they? Tune in to learn the latest on this developing treatment strategy.
ANNOUNCER: Cancer is one of the toughest medical challenges a person can face, and traditional treatments like radiation and chemotherapy can be just as destructive as the disease itself. That's because these treatments, which kill cancer cells, end up killing a lot of other cells in the process. Cells that you need to stay healthy.
But there's a new class of drugs, which are designed to specifically target cancer cells, minimizing damage to the rest of your body. They're called monoclonal antibodies, and they are part of a type of therapy called "immunotherapy."
RALPH BOCCIA, MD: Immunotherapy is specific therapy that utilizes the patient's own immune system to help fight the cancer.
ANNOUNCER: Your immune system is constantly seeking and destroying foreign invaders, so the key is getting it to recognize cancer cells. Monoclonal antibodies achieve this by attaching themselves to specific markers on cancer cells. For non-Hodgkin's lymphoma and chronic lymphocytic leukemia, one such marker is called "CD20" and the drug used to find it is called "Rituximab," commonly known as "rituxan."
RALPH BOCCIA, MD: It's an antibody that was developed against a target on these lymphoid cells that are the cancer cell of a non-Hodgkin's lymphoma. This target is called "CD20." It's a target that sits on the cell's surface of many -- about 90% or so of the B-cell malignant tumors, and only a few of the normal cells.
ANNOUNCER: Once linked to cancer cells, monoclonal antibodies then serve as signals for the immune system to act.
RALPH BOCCIA, MD: It has the ability to attract our normal immune cells, other cells -- one of which we call "natural killer cells," and I think anyone can get a notion of that cell has the capacity to do merely by its name. Then there are the cells called "macrophages," which are very similar cells to the natural killer cells. Their job is to scavenge or to attack foreign substances, germs and, potentially, cancer cells.
ANNOUNCER: Rituximab is also believed to work by activating destructive enzymes and even causing the cancer cells to self-destruct. But the essential advantage of monoclonal antibodies is that they spare the rest of your body from attack, unlike chemotherapy.
RALPH BOCCIA, MD: Chemotherapy has the potential to have a number of side effects that people are very well aware of -- hair loss, nausea, vomiting, fatigue, sometimes infections.
Monoclonal antibody therapy -- which gets the cancer cell as opposed to the normal cell -- if it's not interacting with the normal cell, will reduce that potential for side effects. It won't affect the hair follicle, therefore, the patient's hair won't necessarily fall out.
ANNOUNCER: As with any medication, Rituximab does have some potential side effects.
RALPH BOCCIA, MD: Much like any drug we use, there is the potential that monoclonal antibody will also have side effects. And about 80 to 85% of patients who get rituxan will have some side effect.
The majority of the side effects this drug can cause are called "infusion-related" side effects. That means that during the actual administration or infusion, they have the potential to develop side effects. Those side effects tend to be mild, and tend to be very brief. And they are headache, fever, chills and nausea. Those are the most common side effects, and tend to diminish with each of the infusions.
There's an occasional patient that will actually develop a serious side effect, such as trouble breathing, blood pressure falls. And they tend to be patients with a higher -- what we call -- "tumor burden" (more cancer).
There's a very, very rare incidence of, in fact, a fatal reaction.