OBJECTIVES: Clinical trials are indispensable stage in the development and commercialisation of new medical technologies. Therefore, any perturbations in the conduct of clinical trials can seriously impair introduction of new drugs. This study aims to assess the impact of Covid-19 pandemic on new, ongoing and ended clinical trials in the main health domains.

METHODS: Snapshots from ClinicalTrials.gov database (CTDB) were downloaded in 2020 and updated early 2021. The time series exponential smoothing regression models were fit to the quarterly numbers of new, ongoing and ended trials in the pre-COVID-19 period (2007-2019), and used to forecast the hypothetical trends in 2020 without COVID-19 pandemic. COVID-19 impact was assessed by comparing observed vs forecasted number of trials.

RESULTS: A total of 361,706 clinical trial records retrieved from CTDB were included in the analysis, 78.3% of the studies were interventional. In the first 2 quarters of 2020 the number of ongoing studies was 2.4-2.8% lower compared with the forecasts, which was driven by low rate of newly initiated trials (-13.6 and -10.5%, respectively). The rate of the registration of new trials increased significantly in the second half of 2020, after the first wave of infections had subsided, exceeding the predictions by 10.2% and 21.4% in Q3 and Q4, respectively. However, the overall number of ongoing trials was still below the predictions at the end of the calendar year. The analysis of the subset of COVID-19-unrelated trials shows even more pronounced obstruction caused by COVID-19 pandemic.

CONCLUSIONS: COVID-19 pandemic has affected the conduct of the clinical, which in the global perspective may translate into a significant loss of clinical benefit through a delayed implementation of new technologies. However, the observed adaptation to unfavourable circumstances and the already commenced vaccination programs give hope for a quick normalization of the situation.