Therapeutic and prophylactic effect of intermittent preventive anti-malarial treatment in infants (IPTi) from Ghana and Gabon.
BACKGROUND
Intermittent preventive treatment in infants (IPTi) with sulphadoxine-pyrimethamine (SP) reduces the incidence of malaria episodes in young children. The exact mechanism by which the protective effect is mediated needs to be defined. This study aimed to investigate therapeutic, prophylactic, and possible exceeding effects of SP-based IPTi in two clinical trials.


METHODS
Protective efficacies from two IPTi trials performed in Kumasi, Ghana, and Lambaréné, Gabon, were assessed for overlapping time series of 61 days. For six-months periods after each of three IPTi doses a multivariate Poisson regression model with the respective cohort as co-variate was generated and effect modification of protective efficacy with time strata was evaluated by log-likelihood tests.


RESULTS
Protective efficacies were not significantly different between the two study cohorts. Study-cohort corrected protective efficacy was highest for the first 61 days after each IPTi application and decreased continuously. For the first 61 days after IPTi-1, IPTi-2, and IPTi-3 the protective efficacy was 71%, 44%, and 43%, respectively. A reduction of the malaria incidence rate was detectable for the first 60, 30 and 40 days after IPTi-1, IPTi-2 and IPTi-3 drug application, respectively. After IPTi-3 a higher risk for malaria could be seen after day 60. This effect was mainly based on the overwhelming influence of the Kumasi cohort.


CONCLUSIONS
The results suggest that SP-based IPTi mainly works through a therapeutic and prophylactic effect over 30 to 60 days after drug application and that a sustained effect beyond post-treatment prophylaxis might be very low.


BACKGROUND
Data analysis from clinical trials NCT ID # 00206739 (Kumasi Trial) and NCT ID # 00167843 (Lambaréné Trial), http://www.clinicaltrials.gov.
May
Jürgen
J
Research Group Infectious Disease Epidemiology, Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht Strasse 74, D-20359 Hamburg, Germany. may@bni-hamburg.de
Adjei
Samuel
S
Busch
Wibke
W
Gabor
Julian J
JJ
Issifou
Saadou
S
Kobbe
Robin
R
Kreuels
Benno
B
Lell
Bertrand
B
Schwarz
Norbert G
NG
Adjei
Ohene
O
Kremsner
Peter G
PG
Grobusch
Martin P
MP
D000962:Antimalarials / Q000008:administration & dosage*; D004334:Drug Administration Schedule; D004338:Drug Combinations; D005681:Gabon; D005869:Ghana; D006801:Humans; D007223:Infant; D016778:Malaria, Falciparum / Q000188:drug therapy* / Q000517:prevention & control*; D011739:Pyrimethamine / Q000008:administration & dosage*; D012044:Regression Analysis; D013413:Sulfadoxine / Q000008:administration & dosage*; D013997:Time Factors; D016896:Treatment Outcome
D000962:Antimalarials; D004338:Drug Combinations; C001205:fanasil, pyrimethamine drug combination; D013413:Sulfadoxine; D011739:Pyrimethamine