In 2005, after the 2002-3 SARS epidemic researchers demonstrated the in-vivo anti-viral effect of chloroquine in primate cell lines infected with SARS-CoV (Vincent et al., 2005). These results were further confirmed by Gao et al., Wang et al., and Liu et al.., who also showed inhibitory effects of chloroquine on SARS-CoV-2, the etiological agent of COVID-19. Chloroquine is well known for its anti-malarial properties as well as side-effects, but when used to treat malaria the benefit out-weigh the risks. Hydroxychloroquine a less toxic alternative form of chloroquine, is also used to treat autoimmune diseases such as Lupus and Rheumatoid arthritis, in addition to malaria (McChesney 1983; Touret & de Lamballerie. 2020). As a result, chloroquine has been suggested as a potential COVID-19 treatment and is currently being tested in many trials including the trans-national WHO: SOLIDARITY TRIAL.
Initial clinical studies on small cohorts suggested that chloroquine treatment was associated with improved prognosis (Gauret et al., 2020). However, recently published articles by Molina et al., and Borba et al., (Pre-Print), suggest no beneficial effect of the treatment. Additionally, preliminary results from a randomised clinical trial of chloroquine treatment for COVID-19 by Borba et al., (Pre-Print) further caution against high dose chloroquine treatment for COVID-19, as it leads to cardiovascular adverse effects.
We therefore, eagerly await more reports from clinical trials on the utility of chloroquine as COVID-19 treatment.
References:
- Borba et al., Chloroquine diphosphate in two different dosages as adjunctive therapy of hospitalized patients with severe respiratory syndrome in the context of coronavirus (SARS-CoV-2) infection: Preliminary safety results of a randomized, double-blinded, phase IIb cl MedRxiv Pre-Print
- Gao et al., 2020. Breakthrough: Chloroquine phosphate has shown apparent efficacy in treatment of COVID-19 associated pneumonia in clinical studies. BioScience Trends
- Gauret et al., 2020. Hydroxychloroquine and azithromycin as a treatment of COVID-19: results of an open-label non-randomized clinical trial. International Journal of Antimicrobial agents.
- Liu et al., 2020. Hydroxychloroquine, a less toxic derivative of chloroquine, is effective in inhibiting SARS-CoV-2 infection in vitro. Cell Discovery
- 1983. Animal toxicity and pharmacokinetics of hydroxychloroquine sulfate. American Journal Of Medicine.
- Molina et al., 2020. No Evidence of Rapid Antiviral Clearance or Clinical Benefit with theCombination of Hydroxychloroquine and Azithromycin in Patients withSevere COVID-19 Infection. Médecine et Maladies Infectieuses
- Vincent et al., 2005. Chloroquine is a potent inhibitor of SARS coronavirus infection and spread. BMJ Virology Journal
- Touret & de Lamballerie. 2020. Of chloroquine and COVID-19. Antiviral Research
- Wang et al., 2020. Remdesivir and chloroquine effectively inhibit the recently emerged novel coronavirus (2019-nCoV) in vitro. Cell Research
Article by Cheleka Mpande