As the Covid-19 pandemic continues around the world, companies and researchers are continuously working to find a vaccine or a therapeutic. Drug candidates are currently going through the stages of clinical trial testing, with mixed results. Two of the most high-profile drug candidates are remdesivir and hydroxychloroquine, the latter being an immunosuppressive drug approved for the treatment of malaria and repeatedly praised by US President Donald Trump, who claims to have taken it to ward off Covid-19. The US recently sent two million doses of hydroxychloroquine to Brazil to fight Covid-19 despite no clear scientific evidence for its benefits having emerged thus far. Some studies using hydroxychloroquine have shown no benefits and even an increase in risk of death, but the number of clinical trials investigating hydroxychloroquine as a primary or secondary intervention continues to expand to determine if the drug candidate is a key contender as a therapeutic.
Currently, there are 398 Covid-19 clinical trials using hydroxychloroquine and/or chloroquine as a primary or secondary intervention. Of those 398 clinical trials, 216 (54%) of them are currently ongoing, followed by planned. This signals much more data are on the way to determine if hydroxychloroquine is an effective treatment against Covid-19.
The use of hydroxychloroquine as a treatment in Covid-19 clinical trials is currently under debate. A study published by The Lancet on 22 May 2020 showed that hydroxychloroquine increased the risk of death in Covid-19 patients. The dataset, which included 96,032 patients from 671 hospitals across six continents, has been questioned for discrepancies, but not before the World Health Organization stopped or suspended its own clinical trials of the drug, including its SOLIDARITY TRIAL. The trial, Public Health Emergency SOLIDARITY Trial of Treatments for Covid-19 Infection in Hospitalized Patients, is to evaluate the effectiveness of four different drugs or combinations—remdesivir; a combination of two drugs, lopinavir and ritonavir; the two drugs plus interferon beta; and chloroquine or hydroxychloroquine—when compared to standard of care in subjects with Covid-19. Although the hydroxychloroquine arm of the study is currently temporarily paused, the other arms are continuing. This Phase III trial is expected to enroll 100,000 patients in 35 countries.
France’s Ministry of Solidarity and Health prohibited hospitals from prescribing hydroxychloroquine to patients with Covid-19 two days after the WHO trial suspended its hydroxychloroquine arm. Other European countries following suit include Italy and Belgium. A university in Germany halted a clinical trial with the medication a couple of days after the WHO, France, Italy, and Belgium halted theirs.
Currently, there is no clinical evidence that hydroxychloroquine is effective against Covid-19. As the WHO and countries across the world suspend and even terminate clinical trials based on an increase of adverse events such as mortality and irregular heartbeat, more trials continue to test the drug against Covid-19. Only large, robust, randomised, placebo-controlled clinical trials will show if chloroquine/hydroxychloroquine is effective and safe to use as a treatment for Covid-19.