The co-authors of Invasion of the Prostate Snatchers, blog alternate posts weekly. We invite you to post your comments.

Tuesday, April 8, 2014

Prostate Cancer Clinical Trials


Clinical studies are primarily performed on men with advanced prostate cancer (the Royal Shade of Blue). Why?  The FDA.   FDA only approves new drugs when survival is proven to be prolonged compared to similar men treated with a placebo. The FDA’s insistence on a survival endpoint forces pharmaceutical companies to limit their research to men with a short life expectancy. If survival has to be the endpoint and the study participants live a long time, the cost of performing the study goes up exponentially.

Undergoing experimental therapy with a new medication is reasonable consideration when standard treatment is either no longer working or is causing unacceptable side effects.  However, it’s rare for doctors to recommend an experimental medication before other FDA-approved drugs on the market have been tried.  The commercially available treatments already proven to extend survival are Lupron, Provenge, Xtandi, Zytiga, Xofigo, Taxotere and Jevtana.

Getting Involved in a Trial Can Be Challenging

Eligibility requirements for participation can be rigorous. Trials have carefully specified pretreatment and health status criteria: Eligibility may be denied if the patient is either too sick or not sick enough, if there is too much previous treatment or not enough previous treatment. Criteria are pre-specified so that the final results of the trial are not skewed by a lack of uniformity among patients.  Other requirements designed to achieve trial uniformity include stopping all other anti-cancer medications and the use of placebos, both of which at times may be at variance with a patient’s best interest.
An additional challenge is finding the right trial that matches a patient’s need. The clinical trials landscape changes quickly.  New trials are initiated with limited fanfare and close as soon as they have met their pre-specified number of participants. Trials available at one center may not be so at another.  Another difficulty patient’s face is how to determine the effectiveness of a prospective study drug. Is it likely to work or not?  Due to a study drug’s newness, its functional characteristics are often unclear to patients and doctors alike.
There are different types of study designs to consider each with different goals.  Phase I studies, for example, are primarily designed to learn more about a drug’s side effects. Phase I studies sequentially escalate medication dosages up to determine the point of dosage intolerability. Phase II studies treat a group of patients at a fixed dosage to get a preliminary sense of a drug’s response rates. Phase III studies are the final step that leads up to FDA approval.  Phase III trials are the placebo-controlled trials.
The Business of Clinical Trials
Patients contemplating participation in a clinical trial should be aware that the clinical trial world functions like a business.  It’s funded primarily by the pharmaceutical industry. As such, doctors working in academia are highly motivated to find participants in their research.  If trials are not completed in a timely fashion funding for new trials will be harder to come by in the future.
Participating in a clinical trial has become more attractive over the last ten years as the pharmaceutical industry has made significant strides toward understanding cancer.  Now that they have access to cancer “blueprints” it’s feasible for brilliant biochemists to design “software patches,” new drugs that are far more effective and far less toxic than what has been traditionally available.  However, patients need be careful they don’t mistake a “new” drug for being an “effective” drug.  Despite the tremendous advances in research, most phase I and II drugs still fail to meet minimum standards of clinical effectiveness and never even advance to phase III testing. Sadly, many of the potential prostate drugs that have been tested in Phase III studies over the last ten years have failed to meet the FDA minimum threshold of showing a survival advantage.
Dr. Scholz is the Principal Investigator at Prostate Oncology Specialists - a list of the active trials are found at

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