According to recent proceedings at the 7th International Symposium on GnRH Analogues in Cancer and Human Reproduction, the hormonal agent Plenaxis™ (abarelix) appears to improve quality of life in patients with metastatic prostate cancer.
The prostate is a walnut-sized male sex gland that is located between the bladder and rectum. The prostate is responsible for secreting a substance that forms a component of semen. Treatment options are varied for patients with prostate cancer, often depending upon the stage, or extent, of the disease. Male hormones, particularly testosterone, have growth stimulatory effects on prostate cancer cells. One component of therapy for prostate cancer is called hormone therapy, in which levels of male hormones are reduced in the body. However, many agents used in hormonal therapy cause an initial “surge” in testosterone levels prior to reducing levels. Patients with metastatic prostate cancer, meaning the cancer has spread to distant sites in the body, are often not eligible for these hormone agents due to the risks posed by the testosterone surge. These patients are often treated with surgical castration (removal of the testicles) in order to reduce testosterone levels. Various hormone therapy agents are being evaluated for the treatment of prostate cancer.
Researchers recently conducted a clinical trial to evaluate Plenaxis™ in 72 men with advanced prostate cancer. Plenaxis™ is a hormone agent that reduces levels of testosterone in the body without creating an initial testosterone surge. Men in this trial suffered from at least one of the following symptoms caused by the cancer: bone pain from cancer spread to the bone, obstruction of a part of the urinary system or a high risk of developing a spinal fracture from cancer spread in the spine. These patients would typically have been treated with surgical castration.
At approximately 40 weeks following therapy, no patient had required surgical castration. Furthermore, Plenaxis™ significantly reduced pain in a majority of patients. Prior to therapy, patients rated their pain an average of 7, with 0 being no pain and 10 being the worst pain manageable. By the first week of treatment with Plenaxis™, the average pain rating dropped to 4.4. Twenty four weeks following therapy, the average pain score was less than 1, and 64% of patients suffering from bone pain upon initiation of trial had reduced the dose, frequency and/or potency of narcotic use to ease pain. During the first month of Plenaxis™, the majority of patients suffering from urinary obstruction had improvements in their symptoms. Anti-cancer responses were also demonstrated in 75% of patients at 12 and 24 weeks following therapy.
The researchers concluded that Plenaxis™ appears to improve quality of life in patients with metastatic prostate cancer and demonstrates anti-cancer responses in a significant portion of patients who would otherwise typically have been treated with surgical castration. The company producing Plenaxis™ is seeking FDA approval for its used in advanced, symptomatic prostate cancer for whom the use of existing hormonal agents may not be appropriate. Patients with metastatic prostate cancer who are experiencing symptoms from their cancer may wish to speak with their physician about the risks and benefits of participation in a clinical trial further evaluating Plenaxis™ or other promising therapeutic approaches. Two sources of information regarding ongoing clinical trials include the National Cancer Institute (cancer.gov) and www.eCancerTrials.com. ECancerTrials.com also provides personalized clinical trial searches on behalf of patients.
Reference: Praecis Pharmaceuticals Incorporated. Praecis pharmaceuticals incorporated presents results from clinical trial of Plenaxis in advanced, symptomatic prostate cancer patients. Available at: http://www.corporate-ir.net/media_files/nsd/PRCS/disclaimer.htm. Accessed February 19, 2003.