Glasziou, P. P., Sanders, S. & Hoffmann, T. Br. Med. J. 369, m1847 (2020). Google Scholar The RECOVERY Collaborative Group. N. Engl. J. Med. https://doi.org/10.1056/NEJMoa2021436 (2020). Beigel, J.H. et al. N. Engl. J. Med. https://doi.org/10.1056/NEJMoa2007764 (2020). Yusuf, S., Collins, R. & Peto, R. Stat. Med. 3, 409–422 (1984). CAS Article Google Scholar ISIS Collaborative Group. Lancet 2, 349–360 (1988). Google Scholar Wise, J. & Coombes, R. Br. Med. J. https://doi.org/10.1136/bmj.m2670 (2020). Tenaerts, P., Madre, L. & Landray, M. Clin. Trials 15, 5–12 (2018). CAS Article Google Scholar Muller, M. P., McGeer, A., Straus, S. E., Hawryluck, L. & Gold, W. L. Emerg. Infect. Dis. 10, 389–394 (2004). Article Google Scholar Tansey, C. M., Herridge, M. S., Heslegrave, R. J. & Lavery, J. V. CMAJ 182, 1533–1537 (2010). Article Google Scholar Collins, R., Bowman, L., Landray, M. & Peto, R. N. Engl. J. Med. 382, 674–678 (2020). Article Google Scholar Download references We thank P. Horby and M. Landray (of RECOVERY), A.M. Henao-Restrepo, M.-P. Preziosi, J.-A. Rottingen and V. Sathiyamoorthy (of SOLIDARITY) and N. Peiffer-Smadja and Y. Yazdanpanah (of DisCoVeRy) for insightful advice. K.A.O.T. is supported by the Academy of Finland, Competitive Research Funding of the Helsinki and Uusimaa Hospital District and Sigrid Juselius Foundation. The sponsors had no role in the analysis and interpretation of the data or the manuscript preparation, review, or approval. Departments of Urology and Public Health, University of Helsinki and Helsinki University Hospital, Helsinki, Finland Kari A. O. Tikkinen Department of Surgery, South Karelian Central Hospital, Lappeenranta, Finland Kari A. O. Tikkinen Digestive Disease Research Institute, Tehran University of Medical Sciences, Tehran, Iran Reza Malekzadeh Department of Anesthesiology and Intensive Care, Technical University of Munich School of Medicine, Munich, Germany Martin Schlegel Department of Internal Medicine, Tampere University Hospital, Tampere, Finland Jarno Rutanen Institute for Evidence-Based Healthcare, Bond University, Robina, Australia Paul Glasziou You can also search for this author in PubMed Google Scholar You can also search for this author in PubMed Google Scholar You can also search for this author in PubMed Google Scholar You can also search for this author in PubMed Google Scholar You can also search for this author in PubMed Google Scholar K.A.O.T. and P.G. conceived of and drafted this Correspondence on the basis of interviews with trial investigators; all authors provided comments on the draft and approved the final version. Correspondence to Paul Glasziou. K.A.O.T. is the national principal investigator of the SOLIDARITY trial in Finland; R.M. is the national principal investigator of the SOLIDARITY trial in Iran; M.S. is a steering committee member of the SOLIDARITY trial in Germany; and J.R. is a steering committee member of the SOLIDARITY trial in Finland. Reprints and Permissions Tikkinen, K.A.O., Malekzadeh, R., Schlegel, M. et al. COVID-19 clinical trials: learning from exceptions in the research chaos. Nat Med (2020). https://doi.org/10.1038/s41591-020-1077-z Download citation Published: 22 September 2020 DOI: https://doi.org/10.1038/s41591-020-1077-z