Therapeutic cancer vaccines can help cure prostate cancer patients. However, the technique comes with side effects such as fatigue and increased blood sugar levels that are not well tolerated by many patients. These adverse effects usually lead to the discontinuation of the treatment. New research, however, developed a new strategy to minimize these side effects and thus giving new hope to prostate cancer patients.
Cancer vaccines were developed when researchers discovered that some cancer cells produce some unique proteins in excessive amount. These proteins are unique in a way that they can trigger the immune system to attack the cancer cells. The cancer vaccines were developed by targeting these proteins and stimulate the immune system to attack cancer cells but not the normal cells.
The vaccine for prostate cancer is designed to trigger the immune system to attack prostate-specific antigen (PSA). PSA is a protein produced by the prostate and is found in the blood of men with prostate cancer and non-cancerous conditions. An immune booster called interleukin-2 (IL-2) is normally administered with the vaccine to further boost the body’s natural defense. IL-2, however, brings about the side effects previously described.
“Developing an alternative method of administering vaccine therapy that is well tolerated by most patients and produces similar immune responses to standard methods may help further the development of vaccine therapies for prostate cancer,” according to James L. Gulley of National Cancer Institute’s Center for Cancer Research.
In earlier studies using the same prostate cancer vaccines, IL-2 was given daily for 5 days to 19 patients in every 28-day vaccine treatment cycle. The majority of the patients, however, experiences severe fatigue so that IL-2 was reduced or discontinued.
In the new study led by National Cancer Institute (NCI) researchers, a method called “metronomic dosing” was tested. In this method, 18 patients were treated with vaccine and radiation therapy. The patients were also given the same total amount of IL-2 but were administered daily for 14 days in smaller doses of each 28-treatment cycle. The metronomic dosing showed that less than 25% of the patients experienced side effects that required the reduction of their IL-2 doses. The strategy was found to be safe with fewer side effects but produces similar immune response to the standard dosing method.
However, more research is needed to evaluate the efficacy of this dosing method in the treatment prostate cancer.”
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