CHAPTER 8 CLINICALTRIALS
CLINICAL TRIALS
You may or may not have heard about clinical trials prior to reading this book. Perhaps you heard about them in passing but they didn’t mean much to you.
In the United States new medical treatments have to be approved by a regulatory body named the Food and Drug Administration (FDA).
To get a new treatment approved by the FDA three things have to be demonstrated:
§ It must be proved that the treatment is safe in humans;
§ It must be proved that the treatment produces some beneficial effects in humans;
§ It must be proved that the treatment is better than current treatments that are being used to treat that same disease in humans.
These new treatments are first tested in animals or animal models before they are even considered for testing in humans. You may have come across some research papers in your search of Pub Med which referred to studies done in animals. This means that these new treatments hadn’t even reached the clinical trial phase in humans.
The process for a successful new treatment that is approved by the FDA is the following:
§ The treatment must show good results in testing in the laboratory on animals or animal models;
§ The FDA must then approve the request for testing in humans;
§ The treatment is then tested on a small number of humans to see if it’s safe to use on humans and, if it’s a drug, at what doses. This is phase 1;
§ If the phase 1 trials are successful then the treatment is tested in a larger number of humans to see if any beneficial effect can be seen (for example a beneficial effect would be the shrinking of an actual cancer mass). This is phase 2;
§ If the phase 2 trials are successful then phase 3 trials are started. The treatment is tested in hundreds to thousands of patients and is tested against the best known existing treatments. Only if the new treatment is better than the existing treatments is the new treatment approved by the FDA.
There are a couple of basic facts about the process that are important to keep in mind.
It has been estimated that if 5000 treatments are tested in animals only about 5 will be approved for phase 1 testing in humans.
It has also been estimated that 70% of treatments tested in phase 1 trials will pass. To get a handle on the numbers, imagine that 70 out of 100 treatments that enter phase 1 trials are successful in phase 1.
These 70 treatments then enter phase 2 trials and, on average, slightly less than half of the 70 are successful in phase 2. So, we’re down to about 33 of the original 100.
Of these 33 treatments that enter phase 3 about 25 will be successful.
So, on average, about 25% of the treatments that begin phase 1 testing will prove to be successful.
Another thing to keep in mind is the length of time that the complete clinical trial process takes. It can take anywhere from 5-10 years from beginning to end.
The entire clinical trial process is extraordinarily expensive and has been estimated to cost in the hundreds of millions of dollars for the completion of all 3 phases.
How many people take part in clinical trials?
Recent estimates show that about 3-5% of adult cancer patients take part in clinical trials. Interestingly, the number is much higher in the pediatric population where it is estimated that about 70% of kids take part in clinical trials.
Who sponsors clinical trials?
Clinical trials are sponsored primarily by the government and by pharmaceutical companies. Some are also sponsored by private funds and grants.
Why are clinical trials done?
Governments obviously have an interest in public health so governments fund medical research.
Pharmaceutical companies have a slightly different interest. Since they are for-profit organizations they are looking for new therapies that they can patent and market for profit.
As we will see later, the fact that pharmaceutical companies are in business to make money may mean that certain promising treatments are never studied in the clinical trial process because of business considerations.
Does every doctor take part in clinical trials?
The answer is no. In general, phase 1 studies are the smallest in number and may only test tens of patients. Phase 2 studies usually enroll 100-300 patients and phase 3 studies enroll thousands of patients.
So phase 3 studies tend to take place in many different medical centers.
Should my doctor know about clinical trials?
This is an interesting question. Since there are already commonly accepted and approved treatments for diseases it could be argued that a doctor’s real responsibility is to provide you with the best commonly accepted treatment.
However, some of the treatments that modern medicine considers to be the best offer a poor cure rate. So, one would expect an expert physician to know about some or all of the experimental therapies that are being tested in clinical trials.
But, rest assured, that after reading this chapter you’ll be able to download and present to your doctor a complete list of all the clinical trials that are available to you.
Will my doctor tell me about all the clinical trials that may be ongoing for my disease?
Maybe yes and maybe no. And, that may become an issue when you eventually discuss your therapy. Also, as we’ll discuss later, your doctor may tell you about some trials or a trial in which he or she is involved but may not tell you about other clinical trials that might be available.
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