In vivo efficacy and safety of artemetherlumefantrine and amodiaquine­artesunate for uncomplicated Plasmodium falciparum malaria in Mozambique, 2018

ABSTRACT

Background: Artemisinin-based combination therapy (ACT) has been the recommended first-line treatment for uncomplicated malaria in Mozambique since 2006, with artemether­lumefantrine (AL) and amodiaquine­artesunate (AS­AQ) as the first choice. To assess efficacy of currently used ACT, an in vivo therapeutic efficacy study was conducted. Methods: The study was conducted in four sentinel sites Montepuez, Moatize, Mopeia and Massinga. Patients between 6 and 59 months old with uncomplicated Plasmodium falciparum malaria (2000­200,000 parasites/µl) were enrolled between February and September of 2018, assigned to either an AL or AS­AQ treatment arm, and monitored for 28 days. A Bayesian algorithm was applied to differentiate recrudescence from new infection using genotyping data of seven neutral microsatellites. Uncorrected and PCR-corrected efficacy results at day 28 were calculated. Results: Totals of 368 and 273 patients were enrolled in the AL and AS­AQ arms, respectively. Of these, 9.5% (35/368) and 5.1% (14/273) were lost to follow-up in the AL and AS­AQ arms, respectively. There were 48 and 3 recurrent malaria infections (late clinical and late parasitological failures) in the AL and AS­AQ arms, respectively. The day 28 uncorrected efficacy was 85.6% (95% confidence interval (CI) 81.3­89.2%) for AL and 98.8% (95% CI 96.7­99.8%) for AS­AQ, whereas day 28 PCR-corrected efficacy was 97.9% (95% CI 95.6­99.2%) for AL and 99.6% (95% CI 97.9­100%) for AS­AQ. Molecular testing confirmed that 87.4% (42/48) and 33.3% (1/3) of participants with a recurrent malaria infection in the AL and AS­AQ arms were new infections; an expected finding in a high malaria transmission area. Adverse events were documented in less than 2% of participants for both drugs. Conclusion: Both AL and AS­AQ have therapeutic efficacies well above the 90% WHO recommended threshold and remain well-tolerated in Mozambique. Routine monitoring of therapeutic efficacy should continue to ensure the treatments remain efficacious.