Most people don’t take part in randomised trials, but those people that do are much more likely to take part in another trial in the future. From talking to trial participants the reasons for wanting to take part in a future trial are varied and include the positive experience of the current trial, wanting to continue to contribute to the development of new treatments and, more generally, placing continued trust in the research and research team.
Again from talking to participants the reasons people would not take part in a future trial are related to the breaking of this trust and, specifically, where the research and researchers fail to meet the expectations of the participant. A number of people have said that the current trial they were taking part in failed to recruit and was cancelled and for this reason they would not take part in any future research. These people understandably felt let down by the researchers. They also mentioned that there was a failure to communicate effectively during the trial with examples of participants not being told the trial they were involved in had been cancelled.
I don’t know what the most reliable source of data is, but from my observations on an ethics committee, too many trials get cancelled. Perhaps, 20-30% of trials don’t get completed and that really matters when many people who take part are being let down. These trials usually don’t get published so make up part of the 50% of studies that don’t report. What can be done to change this?
The first thing that needs to change is recognition of the problem. Trials are being cancelled without anybody monitoring the problem. Trials get approved, get started and then can be cancelled without anybody asking any questions. Ethic committees have a unique role to play being the only common point of approval for all types of studies. At present, ethics committees review new applications without any information on the outcome of previous applications from the same sponsors and chief investigators (CIs). Information systems need to be developed that provide the reviewers with data on the outcome of previous trials.
With this information ethics committees would be in a position to act. For example, in reviewing a new application the committee could consider the outcome of the previous say five applications from the same sponsor and/or CI. As a minimum, the committee could inquire about the status of any outstanding trials. It would also be possible to not approve the present study and, instead, the researchers would be asked to first complete these outstanding trials. This seems a reasonable way forward and an effective way to ensure that more trials get completed and reduce an important source of research waste.