The push by pharma companies to develop more targeted compounds in response to unmet medical needs, and the large return on investment these successful therapies generate, has led to an “exuberant rush to market.” Tom Ruane et al. of PAREXEL identify how one consequence of this rush is the increasing difficulty of recruiting and retaining patients with the disease condition and precise genetic profile for which a therapy is intended. They state that any successful clinical trial depends upon the expeditious enrolment of the target patient population.