OBJECTIVE: To investigate the development in the number of applications for authorisation of clinical trials of medicines (CTAs) submitted annually to national competent authorities in 10 Western European member states of the European Union from 2007 to 2015.

DESIGN: Registry study.

SETTING: Data from national competent authorities.

PARTICIPANTS: Germany, Italy, Spain, France, the UK, Belgium, the Netherlands, Austria, Denmark and Sweden. Inclusion criteria were Western European member states of the European Union, receiving more than 200 CTAs per year.

OUTCOME MEASURES: Summarised number of CTAs and distribution of CTAs by type of sponsor (commercial or non-commercial) and trial phase (I-IV). Average annual growth rates (AAGRs) based on linear regressions. Data were evaluated 2007-2011 and 2012-2015 to compare findings with the European Commission's statement of a 25% decrease in CTAs in the EU from 2007 to 2011.

RESULTS: From 2007 to 2011, the summarised number of CTAs decreased significantly (AAGR -3.9% (p=0.02)), primarily due to a decrease in commercially sponsored CTAs. From 2012 to 2015, the change was insignificant (AAGR 2.6% (p=0.27)), however with a 10% increase from 2014 to 2015 after stagnation from 2012 to 2014. Overall, the number of CTAs and distribution by type of sponsor varied considerably between countries. No distinct trends were observed when evaluating CTAs by type of trial phase.

CONCLUSIONS: This study found a significant decrease in the number of CTAs in Western Europe from 2007 to 2011 (AAGR -3.9%). This development is possibly attributable to several factors such as the European Clinical Trials Directive, national and local political decisions, and a potential global shift in clinical trial activity. From 2014 to 2015, the number of CTAs increased markedly (10%). However, it is yet too soon to determine if this constitutes a transient fluctuation or a new trend.