A National Institutes of Health-led phase 3 trial evaluating hydroxychloroquine for the treatment of adults hospitalized with coronavirus disease 2019 (COVID-19) has formally concluded that the drug provides no clinical benefit.

The multicenter, blinded, placebo-controlled ORCHID trial was halted in June 2020 after a data and safety monitoring board determined that hydroxychloroquine was unlikely to benefit hospitalized patients. The trial enrolled 479 adults aged 18 years and older hospitalized with respiratory symptoms from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from April 2 to June 19, 2020, with the last outcome assessment on July 17, 2020. 

Patients were randomized 1:1 to receive either placebo (n=237) or hydroxychloroquine 400mg twice daily for 2 doses, then 200mg twice daily for 8 doses (n=242). The primary end point was clinical status 14 days after randomization as assessed with a 7-category ordinal scale ranging from 1 (death) to 7 (discharged from the hospital and able to perform normal activities).

Results showed that there was no significant difference in clinical status on the ordinal outcome scale at 14 days between the hydroxychloroquine and placebo arms (median interquartile range [IQR] score, 6 [4-7] vs 6 [4-7]; adjusted odds ratio [aOR], 1.02 [95% CI, 0.73-1.42]). Additionally, there were no significant differences observed between the groups with regard to the 12 secondary end points, which included 28 day mortality. At 28 days, 10.4% of patients (25/241) in the hydroxychloroquine arm and 10.6% of patients (25/236) in the placebo arm died (absolute difference, -0.2% [95% CI, -5.7, 5.3]; aOR, 1.07 [95% CI, 0.54-2.09]).  

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“The finding that hydroxychloroquine is not effective for the treatment of COVID-19 was consistent across patient subgroups and for all evaluated outcomes, including clinical status, mortality, organ failures, duration of oxygen use, and hospital length of stay,” said Wesley Self, MD, MPH, emergency medicine physician at Vanderbilt University Medical Center and PETAL Clinical Trials Network investigator who led the ORCHID trial.

For more information visit nih.gov.


  1. Hydroxychloroquine does not benefit adults hospitalized with COVID-19. [press
    release]. Bethesda, MD: National Institutes of Health; November 9, 2020. 
  1. Self WH, Semler MW, Leither LM, et al. Effect of hydroxychloroquine on clinical
    status at 14 days in hospitalized patients with COVID-19. JAMA. Published online
    November 9, 2020. doi: 10.1001/jama.2020.22240.