These studies showed the high therapeutic efficacy of artemether-lumefantrine and artesunate-amodiaquine in Togo between 2005 and 2009. The studies also demonstrated the significant improvement of haemoglobin levels following treatment. In addition, the artemisinin’s gametocytocidal effect was observed by the initial, rapid reduction in gametocytes, and the failure of any new gametocytes to appear over the 28-day period.
In Togo, the efficacy of artemether-lumefantrine was high and did not change between 2005 and 2009, despite the absence of co-administration of fat. This is consistent with a review of studies from sub-Saharan Africa, where it was found that the fat content of standard meals or breast milk was adequate for absorption of lumefantrine
. In 2009, artemether-lumefantrine was the first-line treatment in 29 African countries
. In a review of 140 studies of the therapeutic efficacy of artemether-lumefantrine in Africa
, a PCR-corrected treatment failure rate of higher than 10% was observed in only two studies: 13.8% in Ghana and 12.3% in Burkina Faso
Similarly, the efficacy of artesunate-amodiaquine was high in Togo, and did not change between 2005 and 2009. Two different presentations were used in these studies: loose tablets were used in 2005 and 2007, and co-blistered treatment was used in 2009. Despite different presentations, the treatment outcome did not vary significantly over time. In 2009, artesunate-amodiaquine was the first-line treatment for uncomplicated malaria in 22 African countries
. However, the 28-day therapeutic efficacy of artesunate-amodiaquine varies substantially across the African continent
[8, 10] due to the pre-existing resistance of amodiaquine, which also varies across the continent
. In a 2003 study in Togo, amodiaquine was observed to be over 90% effective, although follow-up was only 14 days
The studies presented here showed an increase in the proportion of reinfections detected in 2007 and 2009 when compared to 2005. The increase in the proportion of reinfections was likely caused by the addition of a third molecular marker, glurp, which improved the ability to distinguish between reinfection and recrudescence. In 2005, only msp1 and msp 2 were used. When glurp was added in 2007 and 2009, the molecular marker detected 53% and 65% of the reinfections, respectively, demonstrating its high ability to discriminate between a reinfection and a recrudescence. Failure to use all three molecular markers in PCR analyses may result in incorrect conclusions regarding the true efficacy of the ACT. These findings demonstrate the importance of following a standardized protocol to enable the comparison of therapeutic efficacy results across sites and over time.
There are very few studies on therapeutic efficacy and drug resistance in Togo. In a literature review, only one publication on the therapeutic efficacy of ACT in Togo was found
. Among 80 patients, 22 were seen on day 3, of whom 20 had cleared their parasites. However, the conclusions from the 2007 study of artemether-lumefantrine are limited, since treatment was not supervised and there was limited follow-up; parents were instructed to return only if their child’s condition persisted after 72 hours. Further, therapeutic efficacy is normally targeted among children under five years of age, and this study was conducted on children aged five years and over.