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Drug Development


Clinical trials planned to put hydroxychloroquine to the test for COVID-19

The antimalaria drug will be tested for treating or preventing the disease in thousands of people worldwide

by Ryan Cross
April 23, 2020 | A version of this story appeared in Volume 98, Issue 16

A bottle of hydroxychloroquine tablets.
Credit: Simone Hogan/Shutterstock
Hydroxychloroquine is approved to treat malaria and immune diseases like lupus and rheumatoid arthritis. Now it is being tested as a treatment for COVID-19.

Over 200,000 people worldwide could receive the old antimalarial drugs chloroquine and hydroxychloroquine across more than 130 clinical trials designed to treat or prevent COVID-19, according to the US clinical trials database.

A small study in March suggested that hydroxychloroquine plus the antibiotic azithromycin helped people with COVID-19 recover faster. President Donald J. Trump touted hydroxychloroquine’s potential in the following weeks, spurring huge demand for the drug. While some doctors prescribed it without proof, others scrambled to construct clinical studies to assess the drug’s efficacy.

The earliest results are discouraging. A team of investigators in Brazil gave chloroquine to 81 hospitalized patients; 32% of those who received high doses died, compared with 15% who received the low dose (medRxiv 2020, DOI: 10.1101/2020.04.07.20056424).

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Separately, data analyzed from 368 people with COVID-19 at hospitals run by the US Veterans Health Administration revealed that 28% who received hydroxychloroquine and 22% who got that drug plus azithromycin died. In contrast, only 11% of those who received neither drug died (medRxiv 2020, DOI: 10.1101/2020.04.16.20065920).

Both studies were preprints, meaning they have not been peer reviewed.

An expert panel at the National Institutes of Health recently recommended against offering hydroxychloroquine plus azithromycin unless it is done in a clinical trial. A 510-person study run by Massachusetts General Hospital and the NIH and a 440-person Novartis study will put the drugs through rigorous, placebo-controlled tests in hospitalized COVID-19 patients. Novartis has already donated 30 million tablets to the US government.

Other groups plan to assess hydroxychloroquine’s potential to prevent COVID-19 by giving it to thousands of healthy health-care workers or people who recently came into contact with a person diagnosed with COVID-19.



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