Effects of point mutations in Plasmodium falciparum dihydrofolate reductase and dihydropterate synthase genes on clinical outcomes and in vitro susceptibility to sulfadoxine and pyrimethamine.
BACKGROUND
Sulfadoxine-pyrimethamine was a common first line drug therapy to treat uncomplicated falciparum malaria, but increasing therapeutic failures associated with the development of significant levels of resistance worldwide has prompted change to alternative treatment regimes in many national malaria control programs. METHODOLOGY AND FINDING: We conducted an in vivo therapeutic efficacy trial of sulfadoxine-pyrimethamine at two locations in the Peruvian Amazon enrolling 99 patients of which, 86 patients completed the protocol specified 28 day follow up. Our objective was to correlate the presence of polymorphisms in P. falciparum dihydrofolate reductase and dihydropteroate synthase to in vitro parasite susceptibility to sulfadoxine and pyrimethamine and to in vivo treatment outcomes. Inhibitory concentration 50 values of isolates increased with numbers of mutations (single [108N], sextuplet [BR/51I/108N/164L and 437G/581G]) and septuplet (BR/51I/108N/164L and 437G/540E/581G) with geometric means of 76 nM (35-166 nM), 582 nM (49-6890- nM) and 4909 (3575-6741 nM) nM for sulfadoxine and 33 nM (22-51 nM), 81 nM (19-345 nM), and 215 nM (176-262 nM) for pyrimethamine. A single mutation present in the isolate obtained at the time of enrollment from either dihydrofolate reductase (164L) or dihydropteroate synthase (540E) predicted treatment failure as well as any other single gene alone or in combination. Patients with the dihydrofolate reductase 164L mutation were 3.6 times as likely to be treatment failures [failures 85.4% (164L) vs 23.7% (I164); relative risk = 3.61; 95% CI: 2.14 - 6.64] while patients with the dihydropteroate synthase 540E were 2.6 times as likely to fail treatment (96.7% (540E) vs 37.5% (K540); relative risk = 2.58; 95% CI: 1.88 - 3.73). Patients with both dihydrofolate reductase 164L and dihydropteroate synthase 540E mutations were 4.1 times as likely to be treatment failures [96.7% vs 23.7%; RR = 4.08; 95% CI: 2.45 - 7.46] compared to patients having both wild forms (I164 and K540).


CONCLUSIONS
In this part of the Amazon basin, it may be possible to predict treatment failure with sulfadoxine-pyrimethamine equally well by determination of either of the single mutations dihydrofolate reductase 164L or dihydropteroate synthase 540E.


BACKGROUND
ClinicalTrials.gov NCT00951106.
Bacon
David J
DJ
Parasitology Program, Naval Medical Research Center Detachment, Lima, Peru. david.bacon@med.navy.mil
Tang
Doug
D
Salas
Carola
C
Roncal
Norma
N
Lucas
Carmen
C
Gerena
Lucia
L
Tapia
Lorena
L
Llanos-Cuentas
A Alejandro
AA
Garcia
Coralith
C
Solari
Lelv
L
Kyle
Dennis
D
Magill
Alan J
AJ
D000818:Animals; D000962:Antimalarials / Q000494:pharmacology*; D004094:Dihydropteroate Synthase / Q000235:genetics*; D010963:Plasmodium falciparum / Q000187:drug effects / Q000201:enzymology*; D017354:Point Mutation; D011739:Pyrimethamine / Q000494:pharmacology*; D013413:Sulfadoxine / Q000494:pharmacology*; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics*
D000962:Antimalarials; D013413:Sulfadoxine; D013762:Tetrahydrofolate Dehydrogenase; D004094:Dihydropteroate Synthase; D011739:Pyrimethamine
Lancet. 1987 Dec 5;2(8571):1304-5
2890904
J Infect Dis. 1997 Dec;176(6):1590-6
9395372
Malar J. 2008 May 27;7:93
18505558
Mol Biochem Parasitol. 2004 Jul;136(1):63-70
15138068
Am J Trop Med Hyg. 2007 Apr;76(4):614-8
17426158
Malar J. 2007 Nov 16;6:153
18021388
Malar J. 2006 Oct 31;5:94
17076899
J Chromatogr B Biomed Sci Appl. 1999 Apr 30;727(1-2):159-65
10360435
Nature. 1978 Jun 22;273(5664):621-2
351412
Antimicrob Agents Chemother. 1979 Dec;16(6):710-8
394674
World Health Organ Tech Rep Ser. 1973;529:1-121
4200089
Acta Trop. 2005 Sep;95(3):172-82
16018959
AIDS. 1999 Mar 11;13(4):487-94
10197377
PLoS Clin Trials. 2006 Jul 21;1(3):e15
16871318
PLoS Clin Trials. 2006 Jul 21;1(3):e14
16871319
Ann Trop Med Parasitol. 2007 Mar;101(2):103-12
17316496
Fundam Clin Pharmacol. 2003 Apr;17(2):147-53
12667224
Am J Trop Med Hyg. 2002 Dec;67(6):578-85
12518847
Am J Trop Med Hyg. 2006 Apr;74(4):546-53
16606982
Am J Trop Med Hyg. 2008 Jun;78(6):892-4
18541765
Am J Trop Med Hyg. 2003 May;68(5):608-12
12812355
Mem Inst Oswaldo Cruz. 2000 Sep-Oct;95(5):721-8
10998224
Am J Trop Med Hyg. 2003 Jan;68(1):120-3
12557836
Rev Soc Bras Med Trop. 2004 May-Jun;37(3):279-81
15330070
Am J Epidemiol. 2002 Aug 1;156(3):230-8
12142257
Trop Med Int Health. 2005 Nov;10(11):1176-9
16262743
Science. 2002 Apr 19;296(5567):545-7
11964483
Lancet. 1998 May 30;351(9116):1629-30
9620719
PLoS One. 2007 Jan 03;2(1):e139
17206274
Am J Trop Med Hyg. 1999 Nov;61(5):802-6
10586915
Antimicrob Agents Chemother. 2007 Jun;51(6):1926-33
17371812
Clin Pharmacol Ther. 2006 Dec;80(6):582-96
17178260
J Infect Dis. 2006 Apr 1;193(7):978-86
16518760
Am J Trop Med Hyg. 2003 Aug;69(2):174-8
14506773
Malar J. 2007 Jan 15;6:2
17224049
Am J Trop Med Hyg. 1995 Jun;52(6):565-8
7611566
Trans R Soc Trop Med Hyg. 2005 May;99(5):341-6
15780340
Am J Trop Med Hyg. 2005 Dec;73(6):1131-4
16354825
Parasitol Res. 2005 Oct;97(4):287-9
16012864
Malar J. 2005 Sep 15;4:42
16164748
Mol Biochem Parasitol. 1998 Aug 1;94(2):205-14
9747971
Antimicrob Agents Chemother. 1985 Apr;27(4):525-30
3890727
J Infect Dis. 1978 Feb;137(2):122-30
627734
Trends Parasitol. 2005 Jun;21(6):292-8
15922251
Trop Med Int Health. 2005 Oct;10(10):1030-7
16185238
J Infect Dis. 2006 Apr 15;193(8):1160-3
16544257
Am J Trop Med Hyg. 2006 Oct;75(4):640-4
17038686
Southeast Asian J Trop Med Public Health. 2001 Mar;32(1):64-9
11485097
J Infect Dis. 2002 Oct 1;186(7):999-1006
12232841
Mol Biol Evol. 2005 Sep;22(9):1834-44
15917494
Science. 2004 Aug 20;305(5687):1124
15326348