• Comparison of different hydroxychloroquine dosages vs. placebo in three cohorts (outpatients, inpatients, healthcare workers a risk). Double-blind RCT for outpatients and healthcare workers and open-label RCT for inpatients (NCT04329923, not yet recruiting). Primary endpoints: (a) release from quarantine (outpatients, follow-up 14 days); (b) discharge (inpatients, follow-up 14 days); (c) development of COVID-19 (healthcare workers, follow-up 2 months). • Comparison of hydroxychloroquine vs. ascorbic acid in contacts of COVID-19 patients. Double-blind RCT (NCT04328961, not yet recruiting). Primary endpoint: laboratory-confirmed COVID-19 (follow-up 14 days). • Comparison of tocilizumab plus hydroxychloroquine plus azithromycin vs. tocilizumab plus hydroxychloroquine in patients with COVID-19. Open-label RCT (NCT04332094, not yet recruiting). Primary endpoints: (a) in-hospital mortality (follow-up 2 weeks); (b) need for mechanical ventilation in the ICU (follow-up 2 weeks).• Comparison of ciclesonide plus hydroxychloroquine vs. ciclesonide in patients with COVID-19. Open-label RCT (NCT04330586, not yet recruiting). Primary endpoint: SARS-CoV-2 eradication (based on virus load) at day 14. • Comparison of hydroxychloroquine vs. placebo in patients with COVID-19 and under biological treatment and/or JAK inhibitors. Double-blind RCT (NCT04330495, not yet recruiting). Primary endpoints: (a) incidence rate of COVID-19 (follow-up 27 weeks); (b) prevalence of COVID-19 (follow-up 27 weeks); (c) case fatality rate (follow-up 27 weeks); (d) ICU admission rate (follow-up 27 weeks). • Comparison of hydroxychloroquine vs. placebo for the prevention of COVID-19 in healthcare workers at risk. Double-blind RCT (NCT04328467, not yet recruiting). Primary endpoint: prevalence of COVID-19 (follow-up 12 weeks). • Comparison of chemoprophylaxis with lopinavir/ritonavir vs. placebo in healthcare workers exposed to COVID-19. Double-blind RCT (NCT04328285, not yet recruiting). Primary endpoint: Occurrence of a symptomatic or asymptomatic SARS-CoV-2 infection (follow-up 2.5 months). • Comparison of hydroxychloroquine vs. placebo in symptomatic COVID-19 patients or exposed healthcare workers/households. Double-blind RCT (NCT04308668, recruiting). Primary endpoints: (a) incidence of symptomatic COVID-19 among asymptomatic participants; (b) severity rating on a 3-point ordinal scale at day 14. • Comparison of remdesivir vs. hydroxychloroquine vs. remdesivir plus hydroxychloroquine in patients with COVID-19. Open-label adaptive RCT (NCT04321616, not yet recruiting). Primary endpoint: all-cause in-hospital mortality (follow-up 3 weeks). • Comparison of lopinavir/ritonavir vs. hydroxychloroquine vs. losartan vs. placebos in patients with COVID-19. Double-blind, adaptive RCT (NCT04328012, not yet recruiting). Primary endpoint: NIAID COVID-19 Ordinal Severity Scale (follow-up 60 days). • Comparison of convalescent plasma plus hydroxychloroquine plus azithromycin vs. hydroxychloroquine plus azithromycin in hospitalized patients with COVID-19. Open-label RCT (NCT04332835, not yet recruiting). Primary endpoints: (a) change in virus load at days 0, 4, 7, 14 and 28; (b) change in IgM COVID-19 titers at days 0, 4, 7, 14 and 28; (c) change in IgG at days 0, 4, 7, 14 and 28. • Comparison of lopinavir/ritonavir vs. hydroxychloroquine vs. lopinavir/ritonavir plus interferon beta-1a vs. remdesivir vs. standard of care in patients with COVID-19. Double-blind, adaptive RCT (NCT04315948, recruiting). Primary endpoint: severity rating on a 7-point ordinal scale at day 15.