The COVID-19 pandemic and new clinical trial activations

From the The Unger Group, Division of Public Health Sciences

Patients with non-COVID-19 diseases have suffered delays and deferments in care due to the COVID-19 pandemic.   As researchers dive into the impacts of the pandemic, there have been questions regarding the changes of clinical research for non-COVID-19 diseases.  In the US alone, the COVID-19 pandemic has caused a devastating number of cases and deaths.  New advances and treatments in medicine for all patients are validated via clinical trials, which aid in verifying the effectiveness of new therapies.  Because of the local and national delays associated with COVID, delays and deferments in clinical trial research could decrease the advancement of new treatments for all diseases.  The Unger Group, from the Division of Public Health Sciences, examined the association of COVID-19 outbreak with new clinical trial activations using data from, which archives all registered domestic and international clinical trials.  Their paper, published in Trials, analyzed the impact of the pandemic on both observational and interventional trials in multiple disease settings, including oncology, cardiovascular, and mental health.

An interrupted time-series approach was used to analyze whether the rate of new trial activations changed in relation to key landmark times related to the COVID-19 pandemic. Three periods were defined, including the pre-pandemic period (2015-January, 2020, when the World Health Organization declared a Public Health Emergency of International Concern), the initial pandemic period (February-May 2020), and the initial US-based reopening period (June-September 2020). Poisson regression was utilized to determine whether total monthly trial actions varied over time. Interaction tests were used to compare US-based and non-US based activations. A five-year time window was chosen for the pre-pandemic period to better model seasonal variation.  

There was a total of 62,252 trial activations examined in the study; over 58,000 were non-COVID-19 trial activations (n=37,204 non-US trials; n=21,684 US trials). The non-COVID-19 activations included oncology (49.8%), cardiovascular (27.5%), mental-health (19.2%), and multiple disease studies (3.4%). Most studies with known data consisted of treatment trials (68.5%) that evaluated systemic therapies (48.9%). Also, 3,364 COVID-19 trial activations were examined (n=725 US trials; n=2,639 non-US trials).  

Graphical Representation of Expected Vs. Actual Number of Clinical Trial Activations During the COVID-19 Initial Pandemic Wave in US
Expected Vs. Actual Number of Clinical Trial Activations During the COVID-19 Initial Pandemic Wave in US Image from Dr. Unger

The research team found that the US monthly trial activations were 57% of the expected estimate if the pandemic had not occurred (RR-0.57, 95% CI: 0.52-0.61). The decrease for non-US based trials, in contrast, was less pronounced, with monthly trial activations at 77% of the expected rate had the pandemic not occurred (RR=0.77, 95% CI: 0.73-0.82). Thus, the reduction for US-based trials was 27% greater than for non-US-based trials. Moreover, during the reopening phase (June 2020-September 2020), the rebound in monthly trial activations was 13% weaker for US-based trials compared to non-US base trials. 

The authors concluded that the COVID-19 pandemic did indeed change the landscape of clinical research for non-COVID diseases, especially in the US. As noted by the authors, the findings of their study are consistent with the outside impact of the COVID-19 pandemic in the US. Dr. Unger, the first author, concluded: “This is the first study to show how the pandemic induced a systemwide slowdown in the activation of new clinical trials for other, non-Covid diseases. The findings also reveal how the COVID-19 pandemic has had ripple effects across research fields, by slowing the development of new treatments for other diseases.” The deferment of clinical trial activations may have limited the discovery of new drugs, thereby effecting long-term negative consequences for patients.  

This research was supported by the Public Health Sciences Division of the Fred Hutchinson Cancer Research Center.

Fred Hutch/UW Cancer Consortium member Joseph Unger contributed to this work.

Unger JM, Xiao H. The COVID-19 pandemic and new clinical trial activations. Trials. 2021 Dec;22(1):1-5.