a monoclonal antibody product called bevacizumab (Avastin). An especially aggressive form of breast cancer, the HER2-positive form of the disease, often responds well to trastuzumab (Herceptin). Monoclonal antibodies can also be used to fight certain types of lymphomas and leukemias.
While generally well-tolerated, monoclonal antibodies can stimulate flu-like symptoms, including fatigue, fever, chills, nausea, and vomiting.
Cytokines. Cytokines are chemical messengers between various parts of the immune system. Some of the cytokines being used for cancer treatment include:
- Interleukins. Interleukins stimulate or regulate immune cells. Some patients with advanced kidney cancer or melanoma (a type of skin cancer) can be completely cured with high-dose interleukin-2 treatment alone, but most will need a combination of treatments.Interleukin-2 (IL-2) can cause severe side effects, and can only be given to people with normal heart and lung function. Due to its toxicity, IL-2 is rarely used anymore. In addition to flu-like symptoms, side effects include weight gain, confusion, and a drop in blood pressure.
- Interferon-alpha. Interferons are produced in response to bacteria, viruses, and parasites. They also have cancer-fighting properties. Interferon-alpha can act directly on cancer cells to slow their growth or help them develop into normal cells. It has been approved for melanoma, certain types of leukemia, and Kaposi sarcoma, a cancer most often seen in HIV/AIDS patients. Studies suggest that interferon-alpha may also be effective in treating kidney cancer and non-Hodgkin lymphoma.Side effects of interferon-alpha can include rashes, loss of appetite, thinning hair, and, ironically, a reduction of infection-fighting white blood cells. If your white blood cells get too low, you might be at risk for infections. In September 2009, the Food and Drug Administration updated the labeling for alpha interferon products to include statements regarding the possible risk of stroke, serious retinal detachment, peripheral neuropathy, and pulmonary hypertension.
Cancer vaccines. Although we commonly think of vaccines as preventive measures, they can also be used to fight an active disease. Scientists hope that injecting fragments of cells or specific cancer-related proteins can stimulate the immune system and be used to treat the disease. In April 2010, the FDA approved the first cancer treatment vaccine. This vaccine, sipuleucel-T (Provenge, manufactured by Dendreon), is approved for use in some men with metastatic prostate cancer.
Preventive vaccines are more common, and two vaccines now in use can prevent certain cancers. A vaccine called Gardasil prevents infection by certain human papillomaviruses (HPV) that can cause cervical cancer. A vaccine against hepatitis B can prevent some cases of liver cancer related to the virus.
Gene therapy. In this experimental field, researchers introduce genetic material (DNA or RNA) into cancer cells. Once inside, these genes produce molecules that might stop cancerous cells from multiplying. There are many ways to go about this — in different experiments, scientists are trying to produce cytokines (to attract a greater immune response), enzymes (to activate drugs), “suicide genes” (to make cancer cells self-destruct), antisense sequences (“opposites” that bind with problem-causing DNA or RNA), or good copies of cancer control genes that have mutated.
Progress in gene therapy has been very slow because of the difficulty of delivering the genes into the cells safely and getting the genes to “turn on” and manufacture the products needed. Despite these obstacles, it has had some success. Cancer gene therapy has been relatively safe; side effects are usually limited to cold or flu-like symptoms.
How will your doctor decide if immunotherapy is right for you?
Not all patients — or all cancers — are good candidates for immunotherapy. At this time, the approach isn’t used very often for patients with cancer of the prostate or ovaries. And if your cancer was caught at an early stage or is responding well to other treatments, immunotherapy may simply not be necessary.
In certain cases, however, immunotherapy does seem to be more effective when used for some smaller, earlier-stage cancers. If your doctor does recommend immunotherapy, you will be getting a cutting-edge treatment that could make a big difference.