The arsenal of prostate cancer treatments for men with advanced prostate cancer may soon be strengthened as the FDA prioritizes the review of both Ra-223 and MDV3100 for treating metastatic castration-resistant prostate cancer (CRPC). Based on positive, independent research of each drug, better survival rates and improved bone health for patients with late-stage prostate cancer may be within reach.
Dr. David Samadi is Vice Chairman, Department of Urology, and Chief of Robotics and Minimally Invasive Surgery at The Mount Sinai Medical Center and a leading robotic surgery expert and PSA test advocate. He commended the efforts behind these advancements by saying, "I'm encouraged to see advanced prostate cancer treatment drugs that may not only extend life, but do so with improved patient health. That's the key – prolonging life with quality." Previous drug therapies, such as Provenge or Zytiga, have proven to extend survival rates, though do not offer additional benefits to the patient.
The drug Radium-223 chloride, also known as Ra-223 or Alpharadin, delivers radiation to the bone and the prostate cancer tumor. In trial, the drug improved patient survival by an average of three months. In addition, patients undergoing Ra-223 drug therapy experienced delayed bone damage or need for surgery or radiation by more than five months.
Medivation, or MDV3100, is an androgen inhibitor that prevents prostate cancer tumor growth by binding with cancer cell receptors. Patient trials with MDV3100 proved improved survival rates by nearly five months. Further, the drug caused tumor shrinkage in close to 30 percent of men, a 50 percent decline in PSA level, and an overall reduction in risk of death by 37 percent.
Improved survival rates of three to five months may sound minimal, but these drugs each present a significant opportunity for men with a disease that, in its advanced stages, can progress very quickly. What's more, experts believe using these drug therapies in a layered approach could provide even greater impact on survival rates for men with metastatic castration-resistant prostate cancers over the next few years.
"In recent months, we've seen the launch of various drug therapies targeting metastatic prostate cancer," said Dr. Samadi, "but the combined survival benefits, tumor shrinkage, and bone improvements with these drugs could lead to a double punch approach. Unlocking the power of how they might work together could mean longer and better lives for these patients." Further research will be conducted to evaluate the extent to which combining or sequencing Ra-223 and MDV3100 would provide additional survival and health benefits.
Prostate cancer is believed to be a hormone-fed disease that thrives in the presence of testosterone. Castration-resistant prostate cancer is named for its resistance to testosterone-lowering treatment therapies.
As a robotic prostatectomy expert, Dr. Samadi addressed the limited benefits of late-stage advancements by saying, "The more we do on the front end of this disease – improving diagnostic tools, getting behind the PSA test for early diagnosis, strengthening treatment choices – the less need there would be for costly drugs that offer relatively short-term returns."
Based on both drugs' exemplary trial results and limited side effects, experts are hopeful that Ra-223 and MDV3100 will become available for FDA-approved patient use this year.
"Men with late-stage prostate cancer deserve every opportunity to extend their time with loved ones. But we can do better; we have the resources to diagnose prostate cancer early. With robotic prostatectomy surgery and other treatments we can address the cancer in time for a full recovery and a long, healthy life," Dr. Samadi concluded.
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