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Massachusetts General Hospital – Hydroxychloroquine

Hydroxychloroquine belongs to the class of drugs called antimalarials. It was initially developed to prevent and treat malaria by eliminating the parasite causing the disease. It is also used to treat rheumatoid arthritis, discoid lupus erythematosus, and systemic lupus erythematosus due to its ability to modify the immune response.

In vitro, hydroxychloroquine was found to inhibit SARS-CoV-2 infection [1]. According to two open-label, non-randomized clinical trials conducted by French researchers, hydroxychloroquine in combination with azithromycin holds the potential for reducing viral load and accelerating recovery of COVID-19 patients [2, 3]. However, a Phase 3 clinical study conducted by Chinese researchers showed inconclusive results for hydroxychloroquine alone [4].

The Massachusetts General Hospital in the United States has initiated ORCHID, a Phase 3 multicenter, blinded, placebo-controlled, randomized clinical trial that has enrolled 510 participants in order to evaluate hydroxychloroquine as a treatment of adults hospitalized with COVID-19 [5]. Primary study results should be available in April 2021, and the study should be completed by July 2021.


  1. Liu, J., Cao, R., Xu, M., Wang, X., Zhang, H., Hu, H., … & Wang, M. (2020). Hydroxychloroquine, a less toxic derivative of chloroquine, is effective in inhibiting SARS-CoV-2 infection in vitro. Cell Discovery, 6(1), 1-4.
  2. Gautret, P., Lagier, J. C., Parola, P., Meddeb, L., Mailhe, M., Doudier, B., … & Honoré, S. (2020). Hydroxychloroquine and azithromycin as a treatment of COVID-19: results of an open-label non-randomized clinical trial. International Journal of Antimicrobial Agents, 105949.
  3. Gautret, P., Lagier J-C., Parola P., Hoang V.T., … & Raoult D., (2020) Clinical and microbiological effect of a combination of hydroxychloroquine and azithromycin in 80 COVID-19 patients with at least a six-day follow up: an observational study. IHU Méditerranée Infection.  
  4. Efficacy and Safety of Hydroxychloroquine for Treatment of Pneumonia Caused by 2019-nCoV ( HC-nCoV )
  5. Outcomes Related to COVID-19 Treated With Hydroxychloroquine Among In-patients With Symptomatic Disease