All new drugs come to market after having been tested in a clinical trial. A clinical trial is the process by which a new drug is evaluated to see if it really makes a difference in the treatment of patients. Sometimes the new drug is tested against a ‘placebo’ (a pill that looks the same as the drug being evaluated, but contains no active medication). Sometimes the new drug is tested against a common medication that is already being used.
In either instance, the evaluation of the new drug is done in what is called a “blinded” fashion. That is, the clinicians evaluating the participants do not know what treatment they are getting, so there is no chance that any preconceived notions that the clinicians have can influence the outcome.
There is widespread agreement that this is the way new medications should be evaluated. Recent experience alone suggests that it is not possible to be sure in advance that a drug is truly effective unless it is tested in this standardized fashion. For example, many scientists believed that estrogen treatment would delay the onset of dementia, but the clinical trial actually showed that older women taking estrogen had an increased risk of dementia rather than a decreased risk.
Despite the importance of clinical trials, not enough people are volunteering to participate in clinical trials for Alzheimer’s disease. The national group of scientists that conducts clinical trials with Alzheimer’s patients (known as the Alzheimer’s Disease Cooperative Study group) has had so much trouble recruiting patients into trials that several trials they have undertaken in the last few years are still incomplete. The leader of this group estimates that only 1 percent of AD patients are in clinical trials.
This is, unfortunately, not a problem unique to Alzheimer’s disease. Leaders of clinical trials in other disease have found the same thing. Only clinical trials in breast cancer appear to be different; in that instance, 3% of patients are enrolled in clinical trials.
The low numbers of people volunteering to be in clinical trials may not only mean that it takes longer to evaluate a new medication to see if it works, but it may also influence the willingness of pharmaceutical companies to invest in Alzheimer’s disease research. Pharmaceutical companies want to know that if there is a promising drug, it will be possible to evaluate it as efficiently as possible.
Large clinical trials are very costly (a single large trial may cost more than 250 million dollars). And the longer it takes to recruit enough participants, the more costly the trial will become. Thus, the difficulty in recruiting patients is one factor in making a decision about whether or not to mount a large clinical trial.
Perhaps one way of changing this situation is to help people understand how important clinical trials are in finding improved drugs for patients. Researchers also need to get a better understanding of the reasons that people are reluctant to volunteer for clinical trials. Both things need to happen in order to find better treatments for Alzheimer’s disease as soon as possible.
This article was contributed by the Johns Hopkins Alzheimer’s Disease Research Center.