Identification of Plitidepsin as Potent Inhibitor of SARS-CoV-2-Induced Cytopathic Effect After a Drug Repurposing Screen

Abstract

There is an urgent need to identify therapeutics for the treatment of Coronavirus disease 2019 (COVID-19). Although different antivirals are given for the clinical management of SARS-CoV-2 infection, their efficacy is still under evaluation. Here, we have screened existing drugs approved for human use in a variety of diseases, to compare how they counteract SARS-CoV-2-induced cytopathic effect and viral replication in vitro. Among the potential 72 antivirals tested herein that were previously proposed to inhibit SARS-CoV-2 infection, only 18 % had an IC50 below 25 µM or 102 IU/ml. These included plitidepsin, novel cathepsin inhibitors, nelfinavir mesylate hydrate, interferon 2-alpha, interferon-gamma, fenofibrate, camostat along the well-known remdesivir and chloroquine derivatives. Plitidepsin was the only clinically approved drug displaying nanomolar efficacy. Four of these families, including novel cathepsin inhibitors, blocked viral entry in a cell—type specific manner. Since the most effective antivirals usually combine therapies that tackle the virus at different steps of infection, we also assessed several drug combinations. Although no particular synergy was found, inhibitory combinations did not reduce their antiviral activity. Thus, these combinations could decrease the potential emergence of resistant viruses. Antivirals prioritized herein identify novel compounds and their mode of action, while independently replicating the activity of a reduced proportion of drugs which are mostly approved for clinical use. Combinations of these drugs should be tested in animal models to inform the design of fast track clinical trials.

Recent advances in developing small-molecule inhibitors against SARS-CoV-2

“…7 ( 67 ) Losartan ‒ ‒ ‒ Phase 1 (NCT04312009, NCT04311177, NCT04328012, NCT04335786, NCT04335123) 162 , 163 , 164 Target TMPRSS2 Fig. 8 ( 68 ) Camostat mesylate In vitro (pseudovirus) ∼1 ＞500 Phase 2a/4 (NCT04321096, NCT04338906) 187 Fig. 8 ( 69 ) Nafamostat In vitro 22.50 ＞100 NCT04352400 19 0.01 ‒ 177 Fig.…”

“…8 ( 71 ) MI-1900 In vitro ＜50 ＞50 Preclinical 180 Target cathepsin B/L Fig. 9 ( 72 ) Amantadine In vitro ＞100 ＞100 Preclinical 187 Fig. 9 ( 73 ) Chlorpromazine In vitro ＞100 ＞100 Preclinical 187 Fig.…”

“…9 ( 73 ) Chlorpromazine In vitro ＞100 ＞100 Preclinical 187 Fig. 9 ( 74 ) E64-d In vitro ∼4.487 ＞00 Preclinical 187 Fig. 9 ( 75 ) Chloroquine In vitro 2.71 273.20 Several clinical trials (ChiCTR2000029609 et al) 97 , 188 , 189 In vitro 2.01 >30 212 Fig.…”

“…10 ( 112 ) Fenofibrate In vitro 20 >100 Preclinical 187 Fig. 10 ( 113 ) Plitidepsin In vivo 0.70 nmol/L for Vero E6; 0.73 nmol/L for hACE2-293T; 1.62 nmol/L for human lung cells 1.99 nmol/L in Vero E6; >200 nmol/L for hACE2-293T; 65.43 nmol/L for human lung cells Phase 1/2 (NCT04382066) 187 , 238 Fig. 10 ( 114 ) Clemizole hydrochloride In vitro 23.94 ＞40 Preclinical 147 Fig.…”

“…Amantadine and chlorpromazine [ Fig. 9 ( 72 , 73 )], which were previously used to abrogate viral entry via clathrin-mediated endocytosis 24 , 186 , proved to have no prominent antiviral efficacy against SARS-CoV-2 and only a partial inhibition at 100 μmol/L for amantadine in Vero E6 cells ( Table 3 ) 187 . E64-d [ Fig.…”