In this issue of Thorax, Lenney and colleagues have described their trials and tribulations with the MASCOT study (see page 457), which compared three different treatment options in children with asthma whose condition was not adequately controlled on low-dose inhaled corticosteroids (ICS).1 The study, which aimed to initially recruit 900 children and enter 450 into a randomised comparison, recently had to close because it had fallen considerably short of its recruitment targets and funding was not extended (by the NIHR Health Technology Assessment Programme). The MASCOT trial was coordinated by the NIHR Medicines for Children Research Network (MCRN) Clinical Trials Unit and supported by the NIHR MCRN and Primary Care Research Networks, which provided an infrastructure of research nurses and other staff to support recruitment of children both in the community and from hospital outpatient clinics. The trial addressed a very important clinical question, but despite a great deal of effort by researchers, clinical trial methodologists and support staff, it failed. Why was this and what lessons can be learnt for the future?

The first series of tribulations that the investigators ran into related to the preparation, packaging and supply of the investigational medicinal products (IMPs) and placebos. To design the trial as a double-blind comparison, among three treatment arms, each child had to take three preparations: ICS plus montelukast and long-acting beta-agonist (LABA) placebo, or ICS plus LABA and montelukast placebo, or ICS plus LABA placebo and montelukast placebo. The investigators depended on two pharmaceutical companies for the supply of these active drugs and placebo. In their section entitled ‘Study progress’, they chronicle a series of problems, which together delayed study initiation by at least 18 months. To maintain the double-blind design, the investigators …