Coronavirus Disease 2019 Treatment: A Review of Early and Emerging Options

McCreary, Erin K; Pogue, Jason M

Although these data are encouraging for the potential role of hydroxychloroquine against SARS-CoV-2, we caution against solely relying on these data to support dosing regimens for patients. The use of 500 mg of chloroquine by mouth twice daily as the reference for efficacy is rational given initial reports from China [16] , but it is important to note that this dosing still requires validation, and the improved R LTEC values reported are largely driven by the finding that hydroxychloroquine was 7.6 times more potent than chloroquine in vitro. Although this enhanced potency may very well prove true as more data become available, this report is counter to the relative potency demonstrated with the structurally similar SARS-CoV-1 strain in 2006 in which chloroquine was approximately 5 times more potent than hydroxychloroquine. In addition, a recently published study has demonstrated that the EC 50 value for chloroquine is 1.13 µM [3] , similar to the value reported for hydroxychloroquine in the analysis by Yao et al [18] .