Participant selection for preventive Regenerative Medicine trials: ethical challenges of selecting individuals at risk

The innovative field of Regenerative Medicine (RM) is expected to extend the possibilities of prevention or early treatment in healthcare. Increasingly, clinical trials will be developed for people at risk of disease to investigate these RM interventions. These individuals at risk are characterised by their susceptibility for developing clinically manifest disease in future due to the existence of degenerative abnormalities. So far, there has been little debate about the ethical appropriateness of including such individuals at risk in clinical trials. We discuss three main challenges of selecting this participant model for testing RM interventions: the challenge of achieving a proportional risk-benefit balance; complexities in the trial design in terms of follow-up and sample size; and the difficulty of obtaining informed consent due to the many uncertainties. We conclude that selecting the model is not ethically justifiable for first-in-man trials with RM interventions due to the high risks and uncertainties. However, the model can be ethically appropriate for testing the efficacy of RM interventions under the following conditions: interventions should be low risk; the degenerative abnormalities (and other risk factors) should be strongly related with disease within a short time frame; robust preclinical evidence of efficacy needs to be present; and the informed consent procedure should contain extra safeguards with regard to communication on uncertainties.