The Food and Drug Administration (FDA) announced that it is working closely with other government agencies and academic centers to investigate the potential use of chloroquine for the treatment of coronavirus disease 2019 (COVID-19).

Chloroquine and hydroxychloroquine (an analog of chloroquine) are indicated for the treatment of malaria, lupus, and rheumatoid arthritis. Recent studies have shown that chloroquine can potentially reduce the duration of symptoms and viral shedding in COVID-19 patients.

Recently, findings were announced from an open-label study investigating hydroxychloroquine in hospitalized patients with confirmed COVID-19 at The Méditerranée Infection University Hospital Institute in Marseille, France. Patients received oral hydroxychloroquine 200mg 3 times daily for 10 days (n=20), and those who refused were part of the control group (n=16). Patients were included if they were 12 years of age and older, and had PCR documented SARS-CoV-2 carriage in nasopharyngeal samples at admission. Treatment with antibiotics (eg, azithromycin) was also provided to patients to prevent bacterial infections. The primary end point was virological clearance at day 6 post-inclusion. 

Results of the study showed that by day 6 post-inclusion, 70% of hydroxychloroquine-treated patients were virologically cured vs 12.5% in the control group (P =.001). Moreover, at day 6 post-inclusion, 100% of patients treated with hydroxychloroquine plus azithromycin were virologically cured compared with 57.1% of patients with hydroxychloroquine only and 12.5% of the control group (P <.001). A significant difference between the hydroxychloroquine and control groups was reported as early as day 3 post-inclusion.

Study investigators noted that 1 patient treated with hydroxychloroquine who was still PCR-positive at day 6 post-inclusion was given azithromycin in addition to hydroxychloroquine at day 8, and was virologically cured at day 9. Conversely, 1 patient treated with the combination therapy who tested negative at day 6, tested positive at low titer at day 8. While the results look promising, the researchers noted limitations to their study including small sample size, limited long-term outcome follow-up, and dropout of 6 patients from the study. 

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In response to the recent interest in chloroquine and hydroxychloroquine, Bayer announced a donation of 3 million tablets of Resochin (chloroquine phosphate) tablets to assist the US government in fighting COVID-19, Teva donated more than 6 million doses of hydroxychloroquine sulfate tablets to hospitals across the US for use as an investigational treatment, and Mylan restarted production of hydroxychloroquine sulfate tablets to meet the potential for increased demand. 

“We understand and recognize the urgency with which we are all seeking prevention and treatment options for COVID-19,” said FDA Commissioner Stephen Hahn, MD. “We also must ensure these products are effective; otherwise we risk treating patients with a product that might not work when they could have pursued other, more appropriate, treatments.”

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