Randomized clinical trials in ANCA-associated vasculitis: a systematic analysis of the WHO - International Clinical Trials Registry Platform

Abstract

Abstract Background The analysis of the main features of randomized controlled trials (RCTs) on ANCA-associated vasculitis (AAV) can inform future study design. Methods We searched within the International Clinical Trials Registry Platform all registered RCTs on AAV from October 2008 to December 2018. Two reviewers selected studies according to pre-specified eligibility criteria. We retrieved information including countries, funding, design, sample sizes, eligibility criteria, primary outcomes (POs), and treatments. Results Among the 40 RCTs identified, 22 (55%) were conducted in Europe, 29 (72,5%) in a single country, 14 (35%) were industry-funded. The median number of patients planned to enrol was 68 (IQR 36–138). Only 28% of RCTs targeted a single vasculitis, and ANCA negative patients were not included in about 40% of studies. Interventions investigated were mainly drugs given to induce (40%) or maintain (32.5%) remission. Eighty-five percent of POs were considered being ‘patient-important’, but discrepancies in definition of disease states, such as remission or relapse were observed. Glucocorticoids use was part of the PO in < 25% of studies. The number of trials targeting a single disease, non-industry funded, incorporating glucocorticoids in PO, as well as the planned sample size increased over time. Conclusion Despite the important achievements in the field, a better harmonization of eligibility, and outcome criteria across studies is an important objective to pursue in next future.