Synthetic biology is a cutting-edge area of research that holds the promise of unprecedented health benefits. However, in tandem with these large prospective benefits, synthetic biology projects entail a risk of catastrophic consequences whose severity may exceed that of most ordinary human undertakings. This is due to the peculiar nature of synthetic biology as a ‘threshold technology’ which opens doors to opportunities and applications that are essentially unpredictable. Fears about these potentially unstoppable consequences have led to declarations from civil society (...) groups calling for the use of a precautionary principle to regulate the field. Moreover, the principle is prevalent in law and international agreements. Despite widespread political recognition of a need for caution, the precautionary principle has been extensively criticized as a guide for regulatory policy. We examine a central objection to the principle: that its application entails crippling inaction and incoherence, since whatever action one takes there is always a chance that some highly improbable cataclysm will occur. In response to this difficulty, which we call the ‘precautionary paradox,’ we outline a deliberative means for arriving at threshold of probability below which potential dangers can be disregarded. In addition, we describe a Bayesian mechanism with which to assign probabilities to harmful outcomes. We argue that these steps resolve the paradox. The rehabilitated PP can thus provide a viable policy option to confront the uncharted waters of synthetic biology research. (shrink)

Randomized Controlled Trials are currently the gold standard within evidence-based medicine. Usually, they are conducted as sequential trials allowing for monitoring for early signs of effectiveness or harm. However, evidence from early stopped trials is often charged with being biased towards implausibly large effects. To our mind, this skeptical attitude is unfounded and caused by the failure to perform appropriate conditioning in the statistical analysis of the evidence. We contend that a shift from unconditional hypothesis tests in the style of (...) Neyman and Pearson to conditional hypothesis tests gives a superior appreciation of the obtained evidence and significantly improves the practice of sequential medical trials, while staying firmly rooted in frequentist methodology. (shrink)

Monitoring ongoing clinical trials for early signs of effectiveness is an option for improving cost-effectiveness of trials that is becoming increasingly common. Alongside the obvious advantages made possible by monitoring, however, there are some downsides. In particular, there is growing concern in the medical community that trials stopped early for benefit tend to overestimate treatment effect. In this paper, I examine this problem from the point of view of statistical methodology, starting from the observation that the overestimation is caused by (...) the statistical method adopted. Consequently, I argue that some modifications can and should be made to the present statistical framework in order not to miss the advantages the possibility of monitoring can grant. (shrink)

Discussions about the merits and shortcomings of non-inferiority trials are becoming increasingly common in the medical community and among regulatory agencies. However, criticisms targeting the ethical standing of non-inferiority trials have often been mistargeted. In this article we review the ethical standing of trials of non-inferiority. In the first part of the article, we outline a consequentialist position according to which clinical trials are best conceived as epistemic tools aimed at fostering the proper ends of medicine. According to this view, (...) clinical trials are means to ends, and thus their moral status depends both on how well they perform as means to reach desired ends and on which ends they are meant to achieve. Building upon this normative framework in the next two sections we analyze the specific ethical issues raised by non-inferiority trials. By making it clear that clinical trials are just epistemic tools – i.e. means to certain ends – it is possible not only to clarify the conceptual debate over a fundamental issue in clinical research, but also to identify which ethically relevant considerations ought to be addressed in setting up a non-inferiority trial. (shrink)

Equipoise, or the criterion of honest professional uncertainty in the clinical community, is currently the most widely accepted standard for adjudicating the ethical dilemmas of medical research involving human patients. Nonetheless, equipoise has recently become a subject of considerable criticism. Among the objections to equipoise, an important one is based on the observation of an objective difficulty for equipoise in providing sound ethical guidance in practical circumstances that arise in clinical research. A chief example of such problem is represented by (...) the case of monitoring accumulating data from a trial. In this article we argue that the perceived inadequacy of equipoise in this context is caused by a widespread misconception of the relation between equipoise and more fundamental ethical principles. We argue that, when interpreted as a mid-level principle, the value of equipoise as the appropriate ethical guidance for clinical research becomes more firmly established. (shrink)