The Challenges of Clinical Trial Recruiting
Though getting more difficult all the time, by no means is this a new problem. Louis Lasagna, a pioneer in clinical pharmacology, came up with what is now called Lasagna's Law, which, in essence says, "The incidence of patient availability sharply decreases when a clinical trial begins and returns to its original level as soon as the trial is completed."
This might be just an inconvenience were it not for the real consequences that can include scotching a trial at its start, extending the duration until enough volunteers can be found, and even failing to complete a trial. Consequently, all trials have a feasibility stage where study sponsors and the contract research organization (CRO) assess the potential recruitment rate.
In an article on Clinical Leader, Dr. Victor Muts addresses the difficulty in getting accurate counts on the likely recruitment rates of appropriate subjects. Despite using all the statistical and modeling tools available, there's still a heavy reliance on estimates from potential investigators at the sites where the trial is to be conducted. And that's become a problem.
"In many instances, the input from the clinical sites proves to be overly optimistic midway through the study and many sponsors and CROs find themselves struggling for the subjects they need, wishing they would have taken investigators’ forecasts with a grain of salt when deciding how many sites they would need to run a successful study," writes Muts.
He lists multiple reasons for the faulty estimates, then suggests a number of ways to improve reliability. Among these are to ask more detailed questions about the reliability of past estimates for other studies, as well as to determine if there are actual patients in the pipeline. Drilling down to get more specific may take extra work, but in the end it could save a trial.
"Ultimately," Muts says, "The investigators should be clear that there are no penalties associated with under-promising and over-delivering."