The usefulness of twenty-four molecular markers in predicting treatment outcome with combination therapy of amodiaquine plus sulphadoxine-pyrimethamine against falciparum malaria in Papua New Guinea.
Details
Serval ID
serval:BIB_6E8A41052EE7
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
The usefulness of twenty-four molecular markers in predicting treatment outcome with combination therapy of amodiaquine plus sulphadoxine-pyrimethamine against falciparum malaria in Papua New Guinea.
Journal
Malaria Journal
ISSN
1475-2875[electronic], 1475-2875[linking]
Publication state
Published
Issued date
2008
Volume
7
Pages
61
Language
english
Abstract
BACKGROUND: In Papua New Guinea (PNG), combination therapy with amodiaquine (AQ) or chloroquine (CQ) plus sulphadoxine-pyrimethamine (SP) was introduced as first-line treatment against uncomplicated malaria in 2000.
METHODS: We assessed in vivo treatment failure rates with AQ+SP in two different areas in PNG and twenty-four molecular drug resistance markers of Plasmodium falciparum were characterized in pre-treatment samples. The aim of the study was to investigate the association between infecting genotype and treatment response in order to identify useful predictors of treatment failure with AQ+SP.
RESULTS: In 2004, Day-28 treatment failure rates for AQ+SP were 29% in the Karimui and 19% in the South Wosera area, respectively. The strongest independent predictors for treatment failure with AQ+SP were pfmdr1 N86Y (OR = 7.87, p < 0.01) and pfdhps A437G (OR = 3.44, p < 0.01). Mutations found in CQ/AQ related markers pfcrt K76T, A220S, N326D, and I356L did not help to increase the predictive value, the most likely reason being that these mutations reached almost fixed levels. Though mutations in SP related markers pfdhfr S108N and C59R were not associated with treatment failure, they increased the predictive value of pfdhps A437G. The difference in treatment failure rate in the two sites was reflected in the corresponding genetic profile of the parasite populations, with significant differences seen in the allele frequencies of mutant pfmdr1 N86Y, pfmdr1 Y184F, pfcrt A220S, and pfdhps A437G.
CONCLUSION: The study provides evidence for high levels of resistance to the combination regimen of AQ+SP in PNG and indicates which of the many molecular markers analysed are useful for the monitoring of parasite resistance to combinations with AQ+SP.
METHODS: We assessed in vivo treatment failure rates with AQ+SP in two different areas in PNG and twenty-four molecular drug resistance markers of Plasmodium falciparum were characterized in pre-treatment samples. The aim of the study was to investigate the association between infecting genotype and treatment response in order to identify useful predictors of treatment failure with AQ+SP.
RESULTS: In 2004, Day-28 treatment failure rates for AQ+SP were 29% in the Karimui and 19% in the South Wosera area, respectively. The strongest independent predictors for treatment failure with AQ+SP were pfmdr1 N86Y (OR = 7.87, p < 0.01) and pfdhps A437G (OR = 3.44, p < 0.01). Mutations found in CQ/AQ related markers pfcrt K76T, A220S, N326D, and I356L did not help to increase the predictive value, the most likely reason being that these mutations reached almost fixed levels. Though mutations in SP related markers pfdhfr S108N and C59R were not associated with treatment failure, they increased the predictive value of pfdhps A437G. The difference in treatment failure rate in the two sites was reflected in the corresponding genetic profile of the parasite populations, with significant differences seen in the allele frequencies of mutant pfmdr1 N86Y, pfmdr1 Y184F, pfcrt A220S, and pfdhps A437G.
CONCLUSION: The study provides evidence for high levels of resistance to the combination regimen of AQ+SP in PNG and indicates which of the many molecular markers analysed are useful for the monitoring of parasite resistance to combinations with AQ+SP.
Keywords
Amodiaquine/pharmacology, Amodiaquine/therapeutic use, Animals, Antimalarials/administration & dosage, Antimalarials/pharmacology, Biological Markers/metabolism, Drug Combinations, Malaria, Falciparum/drug therapy, Malaria, Falciparum/epidemiology, Papua New Guinea/epidemiology, Plasmodium falciparum/drug effects, Plasmodium falciparum/enzymology, Pyrimethamine/pharmacology, Pyrimethamine/therapeutic use, Sulfadoxine/pharmacology, Sulfadoxine/therapeutic use, Treatment Outcome
Pubmed
Open Access
Yes
Create date
03/07/2010 9:23
Last modification date
20/08/2019 15:27