Combined prophylactic and therapeutic use maximizes hydroxychloroquine anti-SARS-CoV-2 effects in vitro

Nicola Clementi; Elena Criscuolo; Roberta Antonia Diotti; Roberto Ferrarese; Matteo Castelli; Roberto Burioni; Massimo Clementi; Nicasio Mancini

On 11 th March 2020, WHO Director-General characterized COVID-19 as a pandemic. As of 27 th March 2020, 549,604 total cases were confirmed, accounting for 24,863 deaths 1 . To date, the clinical management of COVID-19 subjects almost exclusively consists of supportive therapy and, in particular, of ventilatory support for the most severe cases. Several drugs, some already in clinical trials, are currently being used in order to limit the inflammatory response or to hamper SARS-CoV-2 replication. Regarding the latter, no SARS-CoV-2-specific drugs are currently available and, as a consequence, there is the need for repurposing drugs used in other settings, such as chloroquine (CQ) and hydroxychloroquine (HCQ) 2, 3 . Several studies already demonstrated the in vitro efficacy of CQ and HCQ, evidencing the latter's higher activity on SARS-CoV-2 4, 5 . Importantly, a recent study also modeled the main pharmacokinetic features of HCQ trying to infer its lung concentration after different dosing regimens 6 .