The Pros and Cons of Clinical Trials for Prostate Cancer

Clinical studies evaluating new pharmaceutical medications are commonly performed in men with advanced prostate cancer.  Regulatory reasons dictate this reasoning.  The FDA only approves a new prostate cancer drug if the trial establishes a survival advantage compared to placebo.  A mandated survival endpoint forces pharmaceutical companies—for financial reasons—to limit their research to men with a short life expectancy.

 Studies become too costly if they are performed in early-stage prostate cancer patients because their survival commonly extends beyond ten years. 

Finding the Right Clinical Trial Can Be Very Challenging

Patient eligibility requirements for enrollment into a trial can be difficult due to all the pre-specified criteria.  Eligibility may be denied if the patient is either too sick or not sick enough, if there is too much prior treatment or not enough prior treatment.  These rigorous standards are designed to ensure patient uniformity.   However, all these requirements make it a major challenge to find a trial that matches an individual’s cancer profile.  In addition, popular clinical trials accrue patients quickly and may close to any new enrollments.  Trial locations may not be available nationwide, so even the trials that are a profile match, may be geographically undesirable.

The Three Types of Clinical Trials for Cancer Pharmaceuticals

There are three basic categories of clinical trials—Phase I, II and III—each designed to achieve different goals.  Phase I studies, for example, are designed to learn about a drug’s potential side effects.  Phase I studies sequentially escalate medication dosages in a stepwise fashion to determine a point where the dosage of the medication causes intolerable toxicity.

Investigators supervising Phase I trials are curious about whether or not the cancer regresses, but the primary interest is ascertaining the recommended dosage of the new agent for further study in a Phase II trial.

After a Phase I study is completed, a Phase II study may be performed using the dosage ascertained in the Phase I study.  Therefore, a Phase II study evaluates a whole group of men with similar type prostate cancer who are treated at a fixed dosage of the new agent.  The goal of the Phase II study is to determine how often the cancer regresses using that fixed dosage.  Phase II studies of agents, especially agents which have demonstrated previous anticancer activity in Phase I testing, are probably the most desirable type of studies for patients to participate in.  This is because, unlike Phase III trials, all the study participants in a Phase II trial receive full doses of treatment with the real McCoy; no one gets treated with a placebo.

Phase III studies exist primarily to prove a survival advantage to satisfy the FDA and achieve drug approval for commercial usage.

 The advantage of participating in a Phase III trial is the high likelihood that the anticancer agent being tested has genuine anticancer activity.  Otherwise a pharmaceutical company would not be willing to invest major finances to pursue such an expensive endeavor. The unattractive aspect of Phase III trials for patients is the possibility of being allocated to treatment with an inactive placebo.

The Business of Clinical Trials

Patients contemplating participation in a clinical trial should be aware that the clinical trial world functions like a business and it is funded primarily by the pharmaceutical industry.  As such, the whole academic world is highly motivated to find participants in their research. That’s how they get paid.  The doctors in academia are under pressure to find patients to participate in their clinical trials.  The old saying in academia is “Publish or perish.”  The raw material of scientific publication process is patients who are willing to be studied in a clinical trial.

Participating in a clinical trial is becoming more attractive for patients because the pharmaceutical industry is designing much better cancer agents.  These better agents are the fruit of billions of dollars of basic research that has led to understanding how cancer cells function.  Biochemists can now literally design new drugs.  The old system of research that gave us the toxic chemotherapies of yore was based principally on trial and error.  

However, don’t be misled to believe that every new drug is effective.  Despite the tremendous progress, most new drugs never advance beyond Phase I and II testing.  Even Phase III drugs often fail to show enough anticancer oomph to get FDA approval.  So patients who are seeking a clinical trial face two major challenges:  Determining if a new drug has genuine promise and finding a trial that matches their individual characteristics. 

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