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Preclinical evaluation of the antifolate QN254, 5-chloro- N'6'-(2,5-dimethoxy-benzyl)-quinazoline-2,4,6-triamine, as an antimalarial drug candidate

Nzila, A. and Rottmann, M. and Chitnumsub, P. and Kiara, S. M. and Kamchonwongpaisan, S. and Maneeruttanarungroj, C. and Taweechai, S. and Yeung, B. K. and Goh, A. and Lakshminarayana, S. B. and Zou, B. and Wong, J. and Ma, N. L. and Weaver, M. and Keller, T. H. and Dartois, V. and Wittlin, S. and Brun, R. and Yuthavong, Y. and Diagana, T. T.. (2010) Preclinical evaluation of the antifolate QN254, 5-chloro- N'6'-(2,5-dimethoxy-benzyl)-quinazoline-2,4,6-triamine, as an antimalarial drug candidate. Antimicrobial agents and chemotherapy : AAC, Vol. 54, H. 6. pp. 2603-2610.

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Official URL: http://edoc.unibas.ch/dok/A5842990

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Abstract

Drug resistance against dihydrofolate reductase (DHFR) inhibitors-such as pyrimethamine (PM)-has now spread to almost all regions where malaria is endemic, rendering antifolate-based malaria treatments highly ineffective. We have previously shown that the di-amino quinazoline QN254 [5-chloro-N'6'-(2,5-dimethoxy-benzyl)-quinazoline-2,4,6-triamine] is active against the highly PM-resistant Plasmodium falciparum V1S strain, suggesting that QN254 could be used to treat malaria in regions with a high prevalence of antifolate resistance. Here, we further demonstrate that QN254 is highly active against Plasmodium falciparum clinical isolates, displaying various levels of antifolate drug resistance, and we provide biochemical and structural evidence that QN254 binds and inhibits the function of both the wild-type and the quadruple-mutant (V1S) forms of the DHFR enzyme. In addition, we have assessed QN254 oral bioavailability, efficacy, and safety in vivo. The compound displays favorable pharmacokinetic properties after oral administration in rodents. The drug was remarkably efficacious against Plasmodium berghei and could fully cure infected mice with three daily oral doses of 30 mg/kg. In the course of these efficacy studies, we have uncovered some dose limiting toxicity at higher doses that was confirmed in rats. Thus, despite its relative in vitro selectivity toward the Plasmodium DHFR enzyme, QN254 does not show the adequate therapeutic index to justify its further development as a single agent
Faculties and Departments:09 Associated Institutions > Swiss Tropical and Public Health Institute (Swiss TPH) > Department of Medical Parasitology and Infection Biology (MPI) > Parasite Chemotherapy (Mäser)
UniBasel Contributors:Brun, Reto and Wittlin, Sergio
Item Type:Article, refereed
Article Subtype:Research Article
Bibsysno:Link to catalogue
Publisher:American Society for Microbiology
ISSN:0066-4804
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:14 Sep 2012 07:18
Deposited On:14 Sep 2012 06:46

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