Efficacy of artemether-lumefantrine, the nationally-recommended artemisinin combination for the treatment of uncomplicated falciparum malaria, in southern Laos.
BACKGROUND
The Lao Government changed the national policy for uncomplicated Plasmodium falciparum malaria from chloroquine to artemether-lumefantrine (AL) in 2005. Since then, no information on AL efficacy has been reported. With evidence of resistance to artemisinin derivatives in adjacent Cambodia, there has been a concern as to AL efficacy. Monitoring of AL efficacy would help the Lao Government to make decisions on appropriate malaria treatment.


METHODS
The efficacy of a three-day, twice daily oral artemether-lumefantrine for the treatment of uncomplicated falciparum malaria in Xepon District, Savannakhet Province, southern Laos was studied over 42 days follow-up. This was part of a trial of thiamin supplementation in falciparum malaria.


RESULTS
Of 630 patients with P. falciparum enrolled in the trial of thiamin treatment, 549 (87%, 357 children ≤15 years and 192 adults) were included in this study. The per protocol 42-day cure rates were 97% (524/541) [96% (337/352) for children and 99% (187/189) for adults, p = 0.042]. By conventional intention-to-treat analysis, the 42-day cure rates adjusted for re-infection, were 97% (532/549) [96% (342/357) in children and 99% (190/192) in adults, p = 0.042]. The proportion of patients who remained parasitaemic at day 1 after treatment was significantly higher in children [33% (116/356)] compared to adults [15% (28/192)] (p < 0.001) and only one adult patient had detectable parasitaemia on day 2. There were no serious adverse events. Potential side effects after treatment were reported more commonly in adults (32%) compared to children (15%) (p < 0.001). Patients with recrudescent infections were significantly younger, had longer mean time to fever clearance, and had longer median time to parasite clearance compared to those who were cured.


CONCLUSIONS
The current nationally-recommended anti-malarial treatment (artemether-lumefantrine) remains highly efficacious for the treatment of uncomplicated falciparum malaria five years after introduction in Laos. Regular monitoring is required in case artemisinin-resistant P. falciparum parasites should appear.


BACKGROUND
ISRCTN85411059.
Wellcome Trust-Mahosot Hospital-Oxford University Tropical Medicine Research Collaboration, Mahosot Hospital, Vientiane, Lao PDR. mayfong@tropmedres.ac.
Mayfong
M
Mayxay
Maniphone
M
Khanthavong
Odai
O
Chanthongthip
Mallika
M
Imwong
Tiengkham
T
Pongvongsa
Bouasy
B
Hongvanthong
Samalane
S
Phompida
Viengxay
V
Vanisaveth
Nicholas J
NJ
White
Paul N
PN
Newton
D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D000368:Aged; D000962:Antimalarials / Q000008:administration & dosage*; D000077611:Artemether, Lumefantrine Drug Combination; D037621:Artemisinins / Q000008:administration & dosage*; D002648:Child; D002675:Child, Preschool; D004338:Drug Combinations; D004983:Ethanolamines / Q000008:administration & dosage*; D005260:Female; D005449:Fluorenes / Q000008:administration & dosage*; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007812:Laos; D016778:Malaria, Falciparum / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome; D055815:Young Adult
D000962:Antimalarials; D000077611:Artemether, Lumefantrine Drug Combination; D037621:Artemisinins; D004338:Drug Combinations; D004983:Ethanolamines; D005449:Fluorenes