Falciparum malaria remains one of the most important infectious diseases in the world, and the problem is greatest in children and pregnant women in Africa. Among key tools to control and eventually eliminate malaria is intermittent preventive therapy (IPT), the provision of full treatment courses at regular intervals to high risk groups. In Africa, IPT is severely compromised by drug resistance. For treatment of falciparum malaria, older regimens have been replaced by artemisinin-based combination therapies (ACTs). For IPT, a similar change is warranted, and the logical choice is dihydroartemisinin/piperaquine (DHA/PQ), which benefits from rapid killing of most parasites by DHA and protection for weeks after therapy due to the long half-life of PQ. We are now beginning a trial in Uganda that will explore the preventive efficacy and impacts on immune responses of monthly DHA/PQ administered during pregnancy and to infants. We expect that DHA/PQ will offer good preventive efficacy. However, the success of DHA/PQ for IPT is challenged by 3 concerns. First, the pharmacokinetics (PKs) of the regimen, in particular PQ, is not well characterized, especially in pregnant women and young children, and also in the context of IPT. Improved understanding is critical, as available evidence suggests that DHA/PQ is not adequately dosed in young children, and guidelines for pregnancy are lacking. Second, the pharmacodynamics of DHA/PQ are uncertain. What dosing regimens will maximize antimalarial preventive efficacy in target populations? Third, resistance to DHA is spreading in Southeast Asia, and of more immediate concern is resistance to PQ. We describe experiments to better characterize the PKs of DHA/PQ in pregnant women and young children receiving IPT and to characterize associations between exposure to DHA/PQ and risks of malaria and of selection of drug resistance. We hypothesize a) that the PKs of the components of DHA/PQ differ between our target populations and non-pregnant adults, b) that a threshold concentration of PQ will be associated with protection against malaria, and c) that a second lower threshold will define concentrations of PQ that permit malaria infection but select for drug resistant parasites. To test these hypotheses, we will leverage our outstanding infrastructure for malaria research in Tororo, Uganda and link with our funded trial that will assess the preventive efficacy of DHA/PQ. We will add to the trial studies to improve our understanding of the full impact of DHA/PQ, the most important new regimen for the prevention of malaria.
Our specific aims will be (1) to define the PKs of DHA/PQ when used as IPT for Ugandan pregnant women and children, (2) to characterize associations between exposure to PQ and circulating parasitemia, placental malaria, and clinical malaria in pregnant women and children, and (3) to characterize associations between exposure to DHA and PQ and risk of altered drug sensitivity. Overall, our primary goal will be to optimize dosing regimens for IPT with DHA/PQ in pregnant women and children to enable protection against malaria without selection of drug resistance.
Malaria is one of the most important infectious diseases in the world, available control measures are inadequate, and a promising new control strategy is intermittent administration of full treatment doses of dihydroartemisinin/piperaquine (DHA/PQ) to all at-risk individuals. However, optimal dosing strategies for this regimen have not been established, especially for children and pregnant women, the groups at highest risk of malaria. This project will leverage a recently funded clinical trial studying the preventive efficacy of DHA/PQ to evaluate the impacts of drug levels on risks of malaria and selection of drug-resistant parasites, and thereby inform regarding optimal dosing regimens of DHA/PQ to prevent malaria in high risk groups.
|Wallender, Erika; Vucicevic, Katarina; Jagannathan, Prasanna et al. (2018) Predicting Optimal Dihydroartemisinin-Piperaquine Regimens to Prevent Malaria During Pregnancy for Human Immunodeficiency Virus-Infected Women Receiving Efavirenz. J Infect Dis 217:964-972|
|Ali, Ali Mohamed; Penny, Melissa A; Smith, Thomas A et al. (2018) Population Pharmacokinetics of the Antimalarial Amodiaquine: a Pooled Analysis To Optimize Dosing. Antimicrob Agents Chemother 62:|
|Savic, Rada M; Jagannathan, Prasanna; Kajubi, Richard et al. (2018) Intermittent Preventive Treatment for Malaria in Pregnancy: Optimization of Target Concentrations of Dihydroartemisinin-Piperaquine. Clin Infect Dis 67:1079-1088|
|Jagannathan, Prasanna; Kakuru, Abel; Okiring, Jaffer et al. (2018) Dihydroartemisinin-piperaquine for intermittent preventive treatment of malaria during pregnancy and risk of malaria in early childhood: A randomized controlled trial. PLoS Med 15:e1002606|
|Jagannathan, Prasanna; Kajubi, Richard; Aweeka, Francesca T (2018) Response to ""Antiretroviral Therapy With Efavirenz in HIV-Infected Pregnant Women: Understanding the Possible Mechanisms for Drug-Drug Interaction"". Clin Pharmacol Ther 103:571|
|Rasmussen, Stephanie A; Ceja, Frida G; Conrad, Melissa D et al. (2017) Changing Antimalarial Drug Sensitivities in Uganda. Antimicrob Agents Chemother 61:|
|Taylor, Aimee R; Flegg, Jennifer A; Holmes, Chris C et al. (2017) Artemether-Lumefantrine and Dihydroartemisinin-Piperaquine Exert Inverse Selective Pressure on Plasmodium Falciparum Drug Sensitivity-Associated Haplotypes in Uganda. Open Forum Infect Dis 4:ofw229|
|Kajubi, R; Huang, L; Jagannathan, P et al. (2017) Antiretroviral Therapy With Efavirenz Accentuates Pregnancy-Associated Reduction of Dihydroartemisinin-Piperaquine Exposure During Malaria Chemoprevention. Clin Pharmacol Ther 102:520-528|
|Conrad, Melissa D; Mota, Daniel; Foster, Marissa et al. (2017) Impact of Intermittent Preventive Treatment During Pregnancy on Plasmodium falciparum Drug Resistance-Mediating Polymorphisms in Uganda. J Infect Dis 216:1008-1017|
|Nankabirwa, Joaniter I; Conrad, Melissa D; Legac, Jennifer et al. (2016) Intermittent Preventive Treatment with Dihydroartemisinin-Piperaquine in Ugandan Schoolchildren Selects for Plasmodium falciparum Transporter Polymorphisms That Modify Drug Sensitivity. Antimicrob Agents Chemother 60:5649-54|
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