Rapid systematic review on clinical evidence of chloroquine and hydroxychloroquine in COVID-19: critical assessment and recommendation for future clinical trials

Purpose This study aims to critically assess the published studies of Chloroquine (CQ) and hydroxychloroquine (HCQ) for the treatment of COVID-19 and provide recommendations for future clinical trials for the COVID-19 pandemic. Method A rapid systematic review was conducted by searching the PubMed, Embase, and China National Knowledge Infrastructure databases on April 13, 2020. Three clinical trial registry platforms, including ClinicalTrials.gov , the EU Clinical Trials Register, and the Chinese Clinical Trial Register were also complementarily searched. Results A total of 10 clinical studies were identified, including 3 randomized controlled trials (RCTs), 1 comparative nonrandomized trial, 5 single-arm trials, and 1 interim analysis. The heterogeneity among studies of the baseline disease severity and reported endpoints made a pooled analysis impossible. CQ and HCQ (with or without azithromycin) showed significant therapeutic benefit in terms of virologic clearance rate, improvement in symptoms and imaging findings, time to clinical recovery, and length of hospital stay in 1 RCT, 4 single-arm trials, and the interim analysis, whereas no treatment benefit of CQ or HCQ was observed in the remaining 4 studies. Limitations of the included studies ranged from small sample size, to insufficient information concerning baseline patient characteristics, to potential for selection bias without detailing the rationale for exclusion, and presence of confounding factors. Conclusion Based on the studies evaluated, there still lacked solid evidence supporting the efficacy and safety of HCQ and CQ as a treatment for COVID-19 with or without azithromycin. This emphasized the importance of robust RCTs investing HCQ/CQ to address the evidence uncertainties.