Adaptive design clinical trials have seen a marked increase in popularity in recent years. This has been evinced most recently by their use in the 2014 Ebola epidemic and their ongoing methodological elaboration in oncology. In this seminar, I will explore how change in the ‘gold standard’ of the RCT – namely a move from standard to adaptive designs – is being rationalised, legitimised and popularised. Drawing on Adams et al’s (2009) conceptual framework of anticipation, I will argue that changing discourses of time and patienthood have facilitated a move away from standardization as the singular logic of trials towards an appreciation of flexibility, undergirded by probabilistic methodologies. Within this evolving moral economy of medical research, modes of knowledge production which claim to know the future are supplanting the traditional certainties of fixed and standardized experimental designs. I will explore some of the practical and theoretical implications of this for trialists, patients and drug regulators.