Modeling/Forecasting Patient Recruitment in Multicenter Clinical Trials Using Time-dependent Models

Clinical trials in the modern era are characterized by their complexity and high costs and usually involve hundreds/thousands of patients to be recruited across multiple clinical centers in many countries, as typically it is required to achieve a rather large sample size to prove the efficiency of a particular drug. This chapter introduces a natural generalization of the original Poisson-gamma (PG) model to a PG model with non-homogeneous time-dependent rates. It considers some tests on homogeneity of the rates. The chapter discusses the techniques for modeling and simulation of the recruitment using time-dependent model. The technique for estimating parameters using interim data may depend on the form of time dependence. The chapter describes the technique of simulation, which is based on the discrete event simulation approach and used directly in applications.