New variant strains of Covid-19, such as the Delta and now Lambda variants, continue to raise the number of cases around the world. Data captured from GlobalData’s Pharma Intelligence Centre since the beginning of the pandemic show low accrual rate was the top reason for trial termination within clinical trials for Covid-19.

In total, there have been more than 150 trial terminations for Covid-19 trials. The top reason for trial termination was low accrual rate, followed by lack of efficacy and production discontinuation. Low accrual rate accounted for 25.0% of all Covid-19 trial terminations, with lack of efficacy at 14.5%.

A further breakdown can be seen in Figure 1. When looking at trial terminations by phase, the most were seen in Phase II (42.4%) and then Phase III (39.7%), corresponding with the most total trials. Low accrual rate accounted for 52.6% of Phase II trials, followed by 26.3% of Phase III trials. Lastly, North America currently has the most terminated trials by region due to low accrual rate. These numbers may be due to the increase in the number of vaccinations being administered, which lowers the number of patients available.