BackgroundWe describe our experience from a multi-national application of a European Union-funded research-driven paediatric trial (DEEP-2, EudraCT 2012-000353-31; NCT01825512). This paper aims to evaluate the impact of the local and national rules on the trial authorisation process in European and non-European countries. National/local provisions and procedures, number of Ethics Committees and Competent Authorities to be addressed, documentation required, special provisions for the paediatric population, timelines for completing the authorisation process and queries received were collected; compliance with the European provisions were (...) evaluated. Descriptive analysis, Wilcoxon Rank-Sum test and General Linear Model analysis were used to determine factors potentially influencing the timelines. The Cluster Analysis procedure was used to identify homogenous groups of cases.ResultThe authorisation process was completed in 7.7 to 53.8 months in European countries and in 17.1 to 27.1 months in non-European countries. The main factors influencing these timelines were the requests for changes/clarifications in European countries and the different national legislations in non-European countries.ConclusionThis work confirms that the procedures and requirements for the clinical trial application of a paediatric trial are different. In the European Union, the timeframes for submission were generally harmonised but longer. In non-European countries, delays were caused by national dispositions but the entire authorisation process resulted faster with less requests from ECs/cas. The upcoming application of Regulation (EU) 536/2014 is expected to harmonise practices in Europe and possibly outside. Networks on paediatric research acting at international level will be crucial in this effort. (shrink)