The results of two studies carried out in France and China do not support routine use of hydroxychloroquine in hospitalised patients with COVID-19.
In the French study, researchers compared the efficacy of hydroxychloroquine to standard care alone in patients with COVID-19 pneumonia who required oxygen. Of a total of 181 patients, 84 received treatment with hydroxychloroquine within 48 hours of admission (treatment group), at a daily dose of 600mg, and 97 patients received standard care alone (control group).
A weighted analysis found the rate of survival without transfer to the intensive care unit at day 21, the primary outcome, was 76% in the treatment group and 75% in the control group (weighted hazard ratio [WHR] 0.9; 95% CI 0.4–2.1). At day 21, 89% of patients who received hydroxychloroquine survived, compared to 91% of those who received standard care alone (WHR 1.2; 95% CI 0.4–3.3).
The authors of the study said that caution is required in the interpretation of their results, but concluded that their findings do not support the use of hydroxychloroquine in patients hospitalised with COVID-19 pneumonia.
A Chinese study found that patients with mild to moderate COVID-19 who were treated with the antimalarial fought off the virus no more quickly than those who received standard care alone.
In total 150 hospitalised patients with COVID-19 were randomised: 75 were treated with hydroxychloroquine plus standard care and 75 received standard care alone. Over a 2-week trial period, patients in the treatment group with mild to moderate COVID-19 received a loading dose of 1.2g daily for 3 days, followed by a maintenance dose of 800mg daily. Patients with severe COVID-19 were given the 800mg maintenance dose for a further week.
The primary outcome of the study was negative conversion of COVID-19 by day 28. The probability of negative conversion by day 28 in the treatment group was 85.4%, similar to that in the standard of care group (81.3%). However, adverse events were significantly more common in patients who received hydroxychloroquine (30% vs 9%). Diarrhoea was the most common adverse event in the treatment group.
Since the trial was terminated early and only 2 patients with severe disease were enrolled, results for patients with severe disease were not presented. The researchers concluded by saying that although further work is needed to confirm the results, their findings do not support the use of hydroxychloroquine in patients with mild to moderate COVID-19.
In March 2020, following media reports, the MHRA released a statement saying that chloroquine and hydroxychloroquine are not licensed to treat COVID-19 related symptoms or prevent infection in the UK and should not be used to treat COVID-19 outside clinical trials.
Chloroquine and hydroxychloroquine are among four potential COVID-19 treatments being tested in the Solidarity trial, launched by the World Health Organisation and partners.