Prostate Cancer Clinical Trials
Clinical trials are used to assess how possible treatments on diseases can affect the human population. Before a new treatment is introduced for human use, research and testing is done on animals and human derived cells (e.g. from a human cadaver). The United States Food and Drug Administration (FDA) monitor clinical trials being conducted throughout the United States. The FDA does not have the ability to monitor drugs in the clinical stage outside the United States.
Animal testing for prostate cancer mainly involved the use of dogs during the early stages of prostate cancer research. Now, rats and mice have replaced dogs.
The first doctor to test prostate cancer treatments on animals was Charles B. Huggins. Huggins used the anatomy of a dog to test the effects of phosphorus on the male reproductive system. By removal of the testes and reintroducing testosterone back into the system, cancer cells in the prostate gland decreased. Testosterone is a steroid responsible for the growth and development of the male reproductive system. This treatment has been referred to as “Hormone Ablation Therapy.” Hormone Ablation Therapy can be done by surgery or drug administration. Surgery involves removal of the testes to eliminate the production of testosterone. Huggins later concluded that removal of adrenal glands would eliminate further production of DHT (dihydrotestosterone). DHT was found to be a contributory in the production of prostate cancer cells.
Hormone Ablation Therapy by the use of drug administration involves 4 components: control of GnRH hormones, androgen receptor blockade, introduction of 5-alpha inhibitors and combined androgen blockage.
The reproductive systems of the rat and mouse are closely related to the human reproductive system. Because of this, researchers have been able to reproduce mutant cancer cells. Mice have replicated the PIN(prostatic intraepithelial neoplasia(PIN) lesions and invasive prostate cancer.
Once research is completed on animals, clinical trials can begin on human subjects. There are 4 phases of clinical trials: Phase I, Phase II, Phase III and Phase IV. Phase I involves only a few patients and measures the safety administration and efficacy of the drugs or treatment. Phase II is linked to a particular cancer and the new drug or treatment is monitored for the affects of administration on human subjects. Phase III involves patients at hospital, clinics and enrolled cancer centers. The patient will be part of a standardized (this utilizes a control group) or study group(testing an investigational medicine). The standardized trial involves patients taking either a “placebo” or the drug. A placebo does not have chemical ingredients. Phase IV involves maintaining the safety and drug effects on patients who have been medications that have been administered through the clinical trials.
Once a patient has received treatment(surgery, radiation, hormone) for prostate cancer, the patient can make a decision as to whether to enroll in a clinical trial. The patient’s medical providers can give information about what clinical trials are active and the benefits and risks associated with the trial. The risks of a clinical trial include: shutting down the trial due to lack of enrollment or response, will the treatment be effective, and could the medication cause problems. Medication issues are always described because there is always the possibility of interactions but this could happen with any medication. Patients will be asked to complete a form to allow treatment by the research facility. At any time, patients have the right to stop participating in the clinical trial.
There are two organizations that offer a comprehensive list on current prostate cancer clinical trials: the American Cancer Society and the National Cancer Institute. Each organization provides patients and their caregivers the opportunity to research about clinical trials and aid in deciding on whether a clinical trial is right for them.
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