Pharmacokinetic Profiles of Artesunate After Single Intravenous Doses at 0.5, 1, 2, 4, and 8 mg/kg in Healthy Volunteers: A Phase I Study

The human JC polyomavirus (JCPyV) causes the fatal demyelinating disease progressive multifocal leukoencephalopathy (PML). A growing number of patients with induced or acquired immunosuppression are at risk for infection, and no effective antiviral therapy is presently available. The widely used antimalarial drug artesunate has shown broad antiviral activity in vitro but limited clinical success. The aim of this study was to investigate the effect of artesunate on JCPyV replication in vitro. The permissivity for JCPyV MAD-4 was first compared in four cell lines, and the monkey kidney cell line COS-7 was selected. Artesunate caused a concentration-dependent decrease in the extracellular JCPyV DNA load 96 h postinfection, with a 50% effective concentration (EC 50 ) of 2.9 M. This effect correlated with a decreased expression of capsid protein VP1 and a reduced release of infectious viral progeny. For concentrations of <20 M, transient reductions in cellular DNA replication and proliferation were seen, while for higher concentrations, some cytotoxicity was detected. A selective index of 16.6 was found when cytotoxicity was calculated based on cellular DNA replication in the mock-infected cells, but interestingly, cellular DNA replication in the JCPyV-infected cells was more strongly affected. In conclusion, artesunate is efficacious in inhibiting JCPyV replication at micromolar concentrations, which are achievable in plasma. The inhibition at EC 50 probably reflects an effect on cellular proteins and involves transient cytostatic effects. Our results, together with the favorable distribution of the active metabolite dihydroartemisinin to the central nervous system, suggest a potential use for artesunate in patients with PML.

Section: Discussionmentioning

confidence: 99%

Antiviral Effects of Artesunate on JC Polyomavirus Replication in COS-7 Cells

Sharma

Marschall

Rinaldo

2014

“…Oral data presented here contrast with recently reported intravenous (i.v.) data for good manufacturing process (GMP) intravenous artesunate, which found not only rapid hydrolysis of AS to DHA but also much higher C max values for AS than for DHA (22). The comparison suggests high first pass metabolism of AS when given by the oral route.…”

Section: Figmentioning

confidence: 97%

Pharmacokinetics and Pharmacodynamics of Oral Artesunate Monotherapy in Patients with Uncomplicated Plasmodium falciparum Malaria in Western Cambodia

Saunders

Khemawoot

Vanachayangkul

et al. 2012

h Artemisinin-resistant malaria along the Thailand-Cambodian border is an important public health concern, yet mechanisms of drug action and their contributions to the development of resistance are poorly understood. The pharmacokinetics and pharmacodynamics of oral artesunate monotherapy were explored in a dose-ranging trial in an area of emerging artesunate resistance in western Cambodia. We enrolled 143 evaluable subjects with uncomplicated Plasmodium falciparum malaria in an open label study of directly observed artesunate monotherapy at 3 dose levels (2, 4, and 6 mg/kg of body weight/day) for 7 days at Tasanh Health Center, Tasanh, Cambodia. Clinical outcomes were similar among the 3 groups. Wide variability in artesunate and dihydroartemisinin concentrations in plasma was observed. No significant dose-effect or concentration-effect relationships between pharmacokinetic (PK) and parasite clearance parameters were observed, though baseline parasitemia was modestly correlated with increased parasite clearance times. The overall parasite clearance times were prolonged compared with the clearance times in a previous study at this site in 2006 to 2007, but this did not persist when the evaluation was limited to subjects with a comparable artesunate dose (4 mg/kg/day) and baseline parasitemia from the two studies. Reduced plasma drug levels with higher presentation parasitemias, previously hypothesized to result from partitioning into infected red blood cells, was not observed in this population with uncomplicated malaria. Neither in vitro parasite susceptibility nor plasma drug concentrations appeared to have a direct relationship with the pharmacodynamic (PD) effects of oral artesunate on malaria parasites. While direct concentration-effect relationships were not found, it remains possible that a population PK modeling approach that allows modeling of greater dose separation might discern more-subtle relationships. O ral artesunate (AS) is an important drug used in the control of multidrug-resistant Plasmodium falciparum malaria. However, the mechanism of action for this class of drugs, known as the artemisinins, and thus potential mechanisms for development of drug resistance remain poorly understood. Semimechanistic models of parasite dynamics have been proposed to explain the potential effects of drug on parasite sequestration in unmeasurable compartments (16,18). Selective effects of drug on early parasite ring stages were found to explain differences in parasite clearance observed between patients treated in Thailand and Cambodia using intrahost mathematical modeling of pharmacokinetic (PK)-pharmacodynamic (PD) relationships (36). Autoinduction of metabolism has been suggested for drugs in this class (15,17), representing a possible confounder to parasite-based mechanisms of resistance. The current models provide only limited explanations for artesunate resistance, creating an ongoing need for additional empirical data.We recently reported evidence of artesunate resistance in malaria parasites from patient...

“…However, to inhibit the replication of BKV in RPTECs by 50% (i.e., the EC 50 ), a concentration of 4.2 M (1.6 g/ml) artesunate was needed, and it is still unclear if this concentration can be attained in kidney epithelial cells in vivo. Following intravenous administration of artesunate in healthy volunteers, plasma concentrations up to 217 M (83.34 g/ml) have been described (29,53,54), indicating that the EC 50 could at least be achieved in the plasma.…”

Section: Discussionmentioning

confidence: 99%

Antiviral Effects of Artesunate on Polyomavirus BK Replication in Primary Human Kidney Cells

Sharma

Marschall

Henriksen

et al. 2014

dPolyomavirus BK (BKV) causes polyomavirus-associated nephropathy (PyVAN) and hemorrhagic cystitis (PyVHC) in renal and bone marrow transplant patients, respectively. Antiviral drugs with targeted activity against BKV are lacking. Since the antimalarial drug artesunate was recently demonstrated to have antiviral activity, the possible effects of artesunate on BKV replication in human primary renal proximal tubular epithelial cells (RPTECs), the host cells in PyVAN, were explored. At 2 h postinfection (hpi), RPTECs were treated with artesunate at concentrations ranging from 0.3 to 80 M. After one viral replication cycle (approximately 72 hpi), the loads of extracellular BKV DNA, reflecting viral progeny production, were reduced in a concentrationdependent manner. Artesunate at 10 M reduced the extracellular BKV load by 65%; early large T antigen mRNA and protein expression by 30% and 75%, respectively; DNA replication by 73%; and late VP1 mRNA and protein expression by 47% and 64%, respectively. Importantly, the proliferation of RPTECs was also inhibited in a concentration-dependent manner. At 72 hpi, artesunate at 10 M reduced cellular DNA replication by 68% and total metabolic activity by 47%. Cell impedance and lactate dehydrogenase measurements indicated a cytostatic but not a cytotoxic mechanism. Flow cytometry and 5-ethynyl-2=-deoxyuridine incorporation revealed a decreased number of cells in S phase and suggested cell cycle arrest in G 0 or G 2 phase. Both the antiproliferative and antiviral effects of artesunate at 10 M were reversible. Thus, artesunate inhibits BKV replication in RPTECs in a concentration-dependent manner by inhibiting BKV gene expression and genome replication. The antiviral mechanism appears to be closely connected to cytostatic effects on the host cell, underscoring the dependence of BKV on host cell proliferative functions.