Concept and design
A meta-trial employs prospective pooling of individual patient data from ongoing individual clinical trials and early phase studies.[21] The term “meta-trial” refers to a prospective pooled analysis planned to streamline data collection from multiple individual trials, allowing for faster accumulation of data for major clinical endpoints during the pandemic.[24] The meta-trial concept enables researchers to combine the agility of smaller national trials into a much larger international project in a short period of time.[24, 25] Meta-trial interim analysis enables to detect a positive or negative response to the scientific question as soon as an adequate sample size is reached across several countries, thus potentially speeding up the research process dramatically.[24, 26, 27] Adherence to methodological standards of individual trials represents a guarantee of a high level of overall final quality. Furthermore, by estimating the treatment effect across the various trials upfront, the meta-trial may provide stronger evidence in favour of external validity and replicability of the individual trials. Our meta-trial is designed as a collaborative prospective individual patient data analysis of on-going investigator-initiated, randomised studies of inhaled nebulised UFH in addition to standard care compared to standard care alone in hospitalised patients with confirmed COVID-19.