Clinical trials recruitement

It is often difficult for patients to learn about opportunities to participate in clinical trials. Doctors and patient advocacy groups can be valuable resources for patients in search of clinical trial information. Newspapers, particularly in large cities, often carry clinical trial recruitment advertisements. A call to the relevant department at nearby university medical centers can lead to information about clinical trials currently recruiting patients. 

The number of study sites to be used for a clinical trial depends on the characteristics and number of subjects that need to be recruited. Often, a sufficient number of participants cannot be enrolled from a single site, especially if the study inclusion criteria are restrictive and the timeframe for recruitment is limited. In order to complete the study within a reasonable period of time, an inclusion of multiple research centers is often necessary (Chow and Liu, 1998). The selection of study sites depends on several factors including ... 

SPILKER B, CRAMER J A (1992) Patient recruitment in clinical trials. New York, Raven Press. 

The African-American Heart Failure Trial showed that a large number of African Americans can be recruited in sufficient numbers with enough power to show efficacy in a clinical trial. In psychiatry the large START) study of depression was made up of 24% minorities (Trivedi etal, 2006). The recently completed Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) was able to recruit enough African Americans to make up about one third of its participants (Stroup et al, 2006). 

Why are side effects important Imagine that you have been recruited for a clinical trial of an antidepressant medication. As part of the required informed-consent procedure, you are told that you may be given a placebo instead of the active medication, but because this is a double-blind trial, you will not be told which you are getting until the study is over. You are told that... 

It turns out that there is another reason for including a second medication in a clinical trial. You may remember that there is not much difference in effectiveness between one drug and another in the treatment of depression (see Chapter i). So trying to show that the new drug works better is not likely to pay off, and given how expensive clinical trials are and how difficult it can be to recruit subjects for them, a drug company would not want to include an additional arm unless it paid off. So why include it ... 

The most common criticism of our meta-analysis is the claim that the clinical trials we analysed were flawed, and that better results would have been found if the studies had been designed better. The trials were too short to show the real effect of antidepressants, the critics said. The people recruited to participate in them were not depressed enough, or they were too depressed. In any case, they were not representative of the patients who are generally seen in clinical practice. 

Most clinical trials, including the ones my colleagues and I analysed, are conducted on volunteers, many of whom are recruited for the trial by advertisements. Perhaps these depressed people are not as responsive to antidepressants as the patients seen in clinical practice. The STAR D trial that I described earlier was designed specifically to evaluate the effect of antidepressants on the kinds of patients who are typically seen in clinical practice. None of the patients in this trial were recruited by advertising. Instead, they were all patients who sought treatment for depression in family practice or psychiatric out-patient treatment facilities. Also, the usual exclusion criteria were relaxed, so that a broader range of patients was evaluated. The trial did exclude patients who had already tried antidepressants but had not responded to them, although this exclusion should result in better response rates, not worse ones. 

Figure 1.3 shows the expenses versus revenues for a company s investment in developing a new drug. Up until the clinical stage, the investment is substantial in the discovery and development processes. The largest cash demand is in the clinical trial stages, where hundreds and thousands of human subjects have to be recruited to test the drug. 

China offers a large pool of treatment naive patients for clinical trials. There are 1.3 bUhon people, of which 250 milhon are insured and another 250 million partially insured. Chnical trials are one-third the cost of that in the United States and recruitments are expected to be rapid. However, comphcating factors are slower regulatory processes, limited qualified central laboratories for testing, and restriction of export of blood and serum samples outside China for testing. 

Citicoline (cytidinediphosphate-choline/CDP-choline 26) is an intermediate in the biosynthesis of acetylcholine. It has been extensively used for the treatment of neurodegenerative disorders associated with head trauma, stroke, brain aging, and AD. Studies in mice have indicated a protective effect of citicohne against memory impairment induced by adverse environments. A human study recruited 30 patients with mild to moderate AD in a double-blind, randomized and placebo-controlled clinical trial... 

The limitations of the use of biomarkers in healthy volunteers must be recognised. For example, although there have been attempts to simulate migraine headache in volunteers, to date none of these models can be considered adequate to serve as a surrogate endpoint. Patients with migraine are not difficult to recruit and are usually healthy apart from their migraine. In this case, it maybe more appropriate to establish tolerability and pharmacokinetics in healthy volunteers and then to select a maximum well-tolerated dose with which to perform a small proof of principle clinical trial in patients. This will need to be followed by larger trials to establish the dose-response relationship. 

As anyone involved in the conduct of clinical trial knows, it is notoriously difficult to estimate the length of time it will take to recruit patients into a study. Formal inclusion and exclusion criteria can severely restrict the number of patients suitable for a trial, even when common conditions are being studied. An additional and common complication is the overoptimistic investigator syndrome. ... 

Currently, the agency recommends sponsors to recruit more than 10 patients at each centre, and most of the study centres are able to accommodate this number. As the overall number of clinical trials has declined because of the new GCP guidelines and unfavourable pricing rules for the new products, with limited advantage over existing products, it has become relatively easy for the sponsors to meet such requirements than before. 

The IRB is responsible for judging all studies to be conducted at the centre concerned by reviewing protocols, the informed consent sheet, the investigator s brochure and other materials relating to the conduct of clinical trials. The IRB is also responsible for monitoring whether the clinical trials are conducted in compliance with both GCP and IRB s requirements, if any. When the study period of a clinical trial exceeds 1 year the IRB should review the study every year. As the new GCP allows the study sponsor to pay a reasonable amount of money to the study subjects, the IRB is expected to review whether the amount and method of payment is reasonable and does not infringe upon the ethical aspects of the study. Also, the advertisement of a trial for patient recruitment is allowed, but the IRB s approval to implement this at the study centre is required. 

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