A semi-Markov model for patient progression through clinical trials

Clinical trials constitute large, resource-intensive endeavors for pharmaceutical companies, academic institutions and government agencies. Accounts have estimated the number of patients involved in clinical trials in the US as high as 725,000 patients with costs in excess of $19 billion. Despite the scope of these activities, little has been done by way of a general model to highlight the progression of patients through the various stages of a clinical trial. We present a semi-Markov model that can be used to explore the patient population profile of a clinical trial for arbitrarily many patient classes, trial sites and start-times.