Persistent and multiclonal malaria parasite dynamics despite extended artemether-lumefantrine treatment in children

Standard diagnostics used in longitudinal antimalarial studies are unable to characterize the complexity of submicroscopic parasite dynamics, particularly in high transmission settings. We use molecular markers and amplicon sequencing to characterize post-treatment stage-specific malaria parasite dynamics during a 42 day randomized trial of 3- versus 5 day artemether-lumefantrine in 303 children with and without HIV (ClinicalTrials.gov number NCT03453840). The prevalence of parasite-derived 18S rRNA is >70% in children throughout follow-up, and the ring-stage marker SBP1 is detectable in over 15% of children on day 14 despite effective treatment. We find that the extended regimen significantly lowers the risk of recurrent ring-stage parasitemia compared to the standard 3 day regimen, and that higher day 7 lumefantrine concentrations decrease the probability of ring-stage parasites in the early post-treatment period. Longitudinal amplicon sequencing reveals remarkably dynamic patterns of multiclonal infections that include new and persistent clones in both the early post-treatment and later time periods. Our data indicate that post-treatment parasite dynamics are highly complex despite efficacious therapy, findings that will inform strategies to optimize regimens in the face of emerging partial artemisinin resistance in Africa.

Day 3 parasitemia and Plasmodium falciparum Kelch 13 mutations among uncomplicated malaria patients treated with artemether-lumefantrine in Adjumani district, Uganda

Artemisinin resistance threatens malaria control and elimination efforts globally. Recent studies have reported the emergence of Plasmodium falciparum parasites tolerant to artemisinin agents in sub-Saharan Africa, including Uganda. The current study assessed the day 3 parasite clearance and its correlation with P. falciparum K13 propeller gene (pfkelch13) mutations in P. falciparum parasites isolated from patients with uncomplicated malaria under artemether-lumefantrine (AL) treatment. This study enrolled 100 P. falciparum-positive patients to whom AL was prescribed between 09/September/2022 and 06/November/2022. Blood samples were collected in EDTA tubes before treatment initiation (day 0) and on day 3. Parasitemia was assessed by microscopy from blood smears and quantitative polymerase chain reaction (qPCR) from the DNA extracted. The day 0 parasite K13 gene was sequenced using Sanger sequencing. Sequence data were analysed using MEGA version 11 software. The data were analysed using STATA version 15, and the Mann‒Whitney U test was used to compare PCR parasite clearance on day 3 using the comparative CT value method and pfkelch13 mutations. The prevalence of day 3 parasitaemia was 24% (24/100) by microscopy and 63% (63/100) by qPCR from the AL-treated patients. P. falciparum K13-propeller gene polymorphism was detected in 18.8% (15/80) of the day 0 DNA samples. The K13 mutations found were C469Y, 12.5% (10/80); A675V, 2.5% (2/80); A569S, 1.25%, (1/80), A578S, 1.25%, (1/80) and; F491S, 1.25%, (1/80) a new allele not reported anywhere. The C469Y mutation, compared to the wild-type, was associated with delayed parasite clearance p=0.0278, Hodges-Lehmann estimation 3.2108 on the log scale, (95%CI 1.7076, 4.4730). There was a high prevalence of day 3 P. falciparum among malaria patients treated using artemether-lumefantrine. We conclude that the K13 mutation associated with artemisinin resistance by P. falciparum is present in Adjumani district, Uganda. This necessitates regular surveillance of the effectiveness and efficacy of artemether-lumefantrine in the country.

Determination of sulfadoxine and pyrimethamine in microvolume human plasma using ultra high performance liquid chromatography-tandam mass spectrometry

To support the pharmacokinetic study of sulfadoxine (SD) and pyrimethamine (PM) in pregnant women and children, sensitive methods with small sample volume are desirable. Here we report a method to determine SD and PM with microvolume plasma samples: 5 µL plasma samples were cleaned up by protein precipitation with acetonitrile. The deuterated analytes were used as the internal standards. The samples after cleanup were injected onto an ACE Excel SuperC18 column (50 × 2.1 mm, 1.7 μm, Hichrom Limited) connected to a Waters I class UPLC coupled with a Sciex Triple Quad 6500+ Mass Spectrometer and eluted with water and acetonitrile both containing 0.1% formic acid in a gradient mode at 0.8mL/min. Detection utilized ESI+ as the ion source and MRM as the quantification mode. The precursor-to-product ion transitions m/z 311→245 for SD and 249→233 for PM were selected for quantification. The ion transitions for the corresponding internal standards were 315→249 for SD-d4 and 254→235 for PM-d3. The simplest linear regression weighted by 1/x was used for the calibration curves. The calibration ranges were 1-200 µg/mL SD and 2 - 1000ng/mL PM. The mean (± standard deviation) recoveries were 94.3±3.2% (SD) and 97.0±1.5% (PM). The validated method was applied to analysis of 1719 clinical samples, demonstrating the method is suitable for the pharmacokinetic study with samples collected up to day 28 post-dose.

Facilitators and Barriers to Uptake of the Med Safety Mobile App for Adverse Drug Reaction Reporting by Health Workers in Uganda: A Qualitative Study

INTRODUCTION

Adverse drug reactions (ADRs) are an important public health challenge worldwide; however, pharmacovigilance systems are plagued by under-reporting. Mobile technologies, including mobile applications such as Med Safety, could strengthen ADR reporting. We explored the acceptability, and factors that could influence uptake of, Med Safety for ADR reporting by health workers in Uganda.

METHODS

The study took place between July and September 2020 in 12 HIV clinics in Uganda and employed a qualitative exploratory research design. We conducted 22 in-depth interviews and 3 mixed-gender focus group discussions (49 participants) with a diverse range of health workers. We analysed the data using a thematic approach.

RESULTS

There was goodwill among the health workers to adopt Med Safety for ADR reporting and the majority would recommend the app to other health workers. Training with practice increased acceptability of the app. Uptake of the app was favoured by the younger, technology proficient, health worker demographic; the app's offline and two-way risk communication functionalities; availability of free internet hotspots at some health facilities; goodwill and willingness of health workers to report ADRs; and the cumbersome nature of conventional ADR reporting tools. Potential barriers to the uptake of Med Safety were the perceived lengthy processes of initial app registration and completion of multiple screens during ADR reporting; challenges with health workers' smartphones (incompatibility with application, no space for more applications, low battery charge); high cost of internet data; poor internet connectivity; difficulty in recognising ADRs, language barrier and poor feedback to ADR reporters.

CONCLUSION

There was goodwill among the health workers to adopt Med Safety for ADR reporting and the majority would recommend the app to other health workers. Training with practice increased acceptability of the app and should be integral in all future app roll-out campaigns. The identified facilitators and barriers could be used to appropriately guide future research and implementation to promote the uptake of Med Safety for pharmacovigilance in low- and middle-income countries.

Efavirenz-Based Antiretroviral Therapy but Not Pregnancy Increased Unbound Piperaquine Exposure in Women during Malaria Chemoprevention

Dihydroartemisinin-piperaquine (DP) is highly effective for malaria chemoprevention during pregnancy, but the standard dosing of DP that is used for nonpregnant adults may not be optimal for pregnant women. We previously reported that the pharmacokinetic exposure of total piperaquine (PQ; both bound and unbound to plasma proteins) is reduced significantly in the context of pregnancy or efavirenz (EFV)-based antiretroviral therapy (ART). However, as PQ is >99% protein-bound, reduced protein binding during pregnancy may lead to an increase in the pharmacologically active unbound drug fraction (fu), relative to the total PQ. We investigated the impact of pregnancy and EFV use on the fu of PQ to inform the interpretation of pharmacokinetics. Plasma samples from 0 to 24 h after the third (final) DP dose were collected from pregnant women at 28 weeks gestation who were receiving or not receiving EFV-based ART as well as from women 34 to 54 weeks postpartum who were not receiving EFV-based ART, who served as controls. Unbound PQ was quantified via ultrafiltration and liquid chromatography-tandem mass spectrometry, with fu being calculated as PQunbound/PQtotal. The geometric mean fu did not differ between pregnant and postpartum women (P = 0.66), but it was 23% (P < 0.01) greater in pregnant women receiving EFV-based ART, compared to that in postpartum women who were not receiving EFV-based ART. The altered drug-protein binding, potentially due to the displacement of PQ from plasma proteins by EFV, resulted in only a 14% lower unbound PQ exposure (P = 0.13) in the presence of a 31% lower total PQ exposure (P < 0.01), as estimated by the area under the concentration time curve from 0 to 24 h post-last dose in pregnant women who were receiving EFV-based ART. The results suggest that the impact of pregnancy and EFV-based ART on the exposure and, in turn, the efficacy of PQ for malaria prevention may not be as significant as was suggested by the changes in the total PQ exposure. Further study during the terminal elimination phase (e.g., on day 28 post-dose) would help better characterize the unbound PQ exposure during the full dosing interval and, thus, the overall efficacy of PQ for malaria chemoprevention in this special population.

Impact of Drug Exposure on Resistance Selection Following Artemether-Lumefantrine Treatment for Malaria in Children With and Without HIV in Uganda

Artemisinin-based combination therapies (ACTs) are the primary treatment for malaria. It is essential to characterize the pharmacokinetics (PKs) and pharmacodynamics (PDs) of ACTs in vulnerable populations at risk of suboptimal dosing. We developed a population PK/PD model using data from our previous study of artemether-lumefantrine in HIV-uninfected and HIV-infected children living in a high-transmission region of Uganda. HIV-infected children were on efavirenz-, nevirapine-, or lopinavir-ritonavir-based antiretroviral regimens, with daily trimethoprim-sulfamethoxazole prophylaxis. We assessed selection for resistance in two key parasite transporters, pfcrt and pfmdr1, over 42-day follow-up and incorporated genotyping into a time-to-event model to ascertain how resistance genotype in relation to drug exposure impacts recurrence risk. Two hundred seventy-seven children contributed 364 episodes to the model (186 HIV-uninfected and 178 HIV-infected), with recurrent microscopy-detectable parasitemia detected in 176 episodes by day 42. The final model was a two-compartment model with first-order absorption and an estimated age effect on bioavailability. Systemic lumefantrine exposure was highest with lopinavir-ritonavir, lowest with efavirenz, and equivalent with nevirapine and HIV-uninfected children. HIV status and lumefantrine concentration were significant factors associated with recurrence risk. Significant selection was demonstrated for pfmdr1 N86 and pfcrt K76 in recurrent infections, with no evidence of selection for pfmdr1 Y184F. Less sensitive parasites were able to tolerate lumefantrine concentrations ~ 3.5-fold higher than more sensitive parasites. This is the first population PK model of lumefantrine in HIV-infected children and demonstrates selection for reduced lumefantrine susceptibility, a concern as we confront the threat to ACTs posed by emerging artemisinin resistance in Africa.

The Impact of Extended Treatment With Artemether-lumefantrine on Antimalarial Exposure and Reinfection Risks in Ugandan Children With Uncomplicated Malaria: A Randomized Controlled Trial

BACKGROUND

Artemether-lumefantrine (AL) is the most widely used artemisinin-based combination therapy in Sub-Saharan Africa and is threatened by the emergence of artemisinin resistance. Dosing is suboptimal in young children. We hypothesized that extending AL duration will improve exposure and reduce reinfection risks.

METHODS

We conducted a prospective, randomized, open-label pharmacokinetic/pharmacodynamic study of extended duration AL in children with malaria in high-transmission rural Uganda. Children received 3-day (standard 6-dose) or 5-day (10-dose) AL with sampling for artemether, dihydroartemisinin, and lumefantrine over 42-day clinical follow-up. Primary outcomes were (1) comparative pharmacokinetic parameters between regimens and (2) recurrent parasitemia analyzed as intention-to-treat.

RESULTS

A total of 177 children aged 16 months to 16 years were randomized, contributing 227 total episodes. Terminal median lumefantrine concentrations were significantly increased in the 5-day versus 3-day regimen on days 7, 14, and 21 (P < .001). A predefined day 7 lumefantrine threshold of 280 ng/mL was strongly predictive of recurrence risk at 28 and 42 days (P < .001). Kaplan-Meier estimated 28-day (51% vs 40%) and 42-day risk (75% vs 68%) did not significantly differ between 3- and 5-day regimens. No significant toxicity was seen with the extended regimen.

CONCLUSIONS

Extending the duration of AL was safe and significantly enhanced overall drug exposure in young children but did not lead to significant reductions in recurrent parasitemia risk in our high-transmission setting. However, day 7 levels were strongly predictive of recurrent parasitemia risk, and those in the lowest weight-band were at higher risk of underdosing with the standard 3-day regimen.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov number NCT03453840.

Effectiveness of the Med Safety mobile application in improving adverse drug reaction reporting by healthcare professionals in Uganda: a protocol for a pragmatic cluster-randomised controlled trial

INTRODUCTION

Combination antiretroviral therapy (cART) has massively reduced HIV mortality. However, long-term cART increases the risk of adverse drug reactions (ADRs), which can lead to higher morbidity, mortality and healthcare costs for people living with HIV (PLHIV).Pharmacovigilance-monitoring the effects of medicines-is essential for understanding real-world drug safety. In Uganda, pharmacovigilance systems have only recently been developed, and rates of ADR reporting for cART are very low. Thus, the safety profile of medicines currently used to treat HIV and tuberculosis in our population is poorly understood.The Med Safety mobile application has been developed through the European Union's Innovative Medicines Initiative WEB-Recognising Adverse Drug Reactions project to promote digital pharmacovigilance. This mobile application has been approved for ADR-reporting by Uganda's National Drug Authority. However, the barriers and facilitators to Med Safety uptake, and its effectiveness in improving pharmacovigilance, are as yet unknown.

METHODS AND ANALYSIS

A pragmatic cluster-randomised controlled trial will be implemented over 30 months at 191 intervention and 191 comparison cART sites to evaluate Med Safety. Using a randomisation sequence generated by the sealed envelope software, we shall randomly assign the 382 prescreened cART sites to the intervention and comparison arms. Each cART site is a cluster that consists of healthcare professionals and PLHIV receiving dolutegravir-based cART and/or isoniazid preventive therapy. Healthcare professionals enrolled in the intervention arm will be trained in the use of mobile-based, paper-based and web-based reporting, while those in the comparison arm will be trained in paper-based and web-based reporting only.

ETHICS AND DISSEMINATION

Ethical approval was given by the School of Biomedical Sciences Research and Ethics Committee at Makerere University (SBS-REC-720), and administrative clearance was obtained from Uganda National Council for Science and Technology (HS1366ES). Study results will be shared with healthcare professionals, policymakers, the public and academia.

TRIAL REGISTRATION NUMBER

PACTR202009822379650.

Efficacy and tolerability of artemisinin-based and quinine-based treatments for uncomplicated falciparum malaria in pregnancy: a systematic review and individual patient data meta-analysis

BACKGROUND

Malaria in pregnancy affects both the mother and the fetus. However, evidence supporting treatment guidelines for uncomplicated (including asymptomatic) falciparum malaria in pregnant women is scarce and assessed in varied ways. We did a systematic literature review and individual patient data (IPD) meta-analysis to compare the efficacy and tolerability of different artemisinin-based or quinine-based treatments for malaria in pregnant women.

METHODS

We did a systematic review of interventional or observational cohort studies assessing the efficacy of artemisinin-based or quinine-based treatments in pregnancy. Seven databases (MEDLINE, Embase, Global Health, Cochrane Library, Scopus, Web of Science, and Literatura Latino Americana em Ciencias da Saude) and two clinical trial registries (International Clinical Trials Registry Platform and ClinicalTrials.gov) were searched. The final search was done on April 26, 2019. Studies that assessed PCR-corrected treatment efficacy in pregnancy with follow-up of 28 days or more were included. Investigators of identified studies were invited to share data from individual patients. The outcomes assessed included PCR-corrected efficacy, PCR-uncorrected efficacy, parasite clearance, fever clearance, gametocyte development, and acute adverse events. One-stage IPD meta-analysis using Cox and logistic regression with random-effects was done to estimate the risk factors associated with PCR-corrected treatment failure, using artemether-lumefantrine as the reference. This study is registered with PROSPERO, CRD42018104013.

FINDINGS

Of the 30 studies assessed, 19 were included, representing 92% of patients in the literature (4968 of 5360 episodes). Risk of PCR-corrected treatment failure was higher for the quinine monotherapy (n=244, adjusted hazard ratio [aHR] 6·11, 95% CI 2·57-14·54, p<0·0001) but lower for artesunate-amodiaquine (n=840, 0·27, 95% 0·14-0·52, p<0·0001), artesunate-mefloquine (n=1028, 0·56, 95% 0·34-0·94, p=0·03), and dihydroartemisinin-piperaquine (n=872, 0·35, 95% CI 0·18-0·68, p=0·002) than artemether-lumefantrine (n=1278) after adjustment for baseline asexual parasitaemia and parity. The risk of gametocyte carriage on day 7 was higher after quinine-based therapy than artemisinin-based treatment (adjusted odds ratio [OR] 7·38, 95% CI 2·29-23·82).

INTERPRETATION

Efficacy and tolerability of artemisinin-based combination therapies (ACTs) in pregnant women are better than quinine. The lower efficacy of artemether-lumefantrine compared with other ACTs might require dose optimisation.

FUNDING

The Bill & Melinda Gates Foundation, ExxonMobil Foundation, and the University of Oxford Clarendon Fund.

Pregnancy outcomes and risk of placental malaria after artemisinin-based and quinine-based treatment for uncomplicated falciparum malaria in pregnancy: a WorldWide Antimalarial Resistance Network systematic review and individual patient data meta-analysis

BACKGROUND

Malaria in pregnancy, including asymptomatic infection, has a detrimental impact on foetal development. Individual patient data (IPD) meta-analysis was conducted to compare the association between antimalarial treatments and adverse pregnancy outcomes, including placental malaria, accompanied with the gestational age at diagnosis of uncomplicated falciparum malaria infection.

METHODS

A systematic review and one-stage IPD meta-analysis of studies assessing the efficacy of artemisinin-based and quinine-based treatments for patent microscopic uncomplicated falciparum malaria infection (hereinafter uncomplicated falciparum malaria) in pregnancy was conducted. The risks of stillbirth (pregnancy loss at ≥ 28.0 weeks of gestation), moderate to late preterm birth (PTB, live birth between 32.0 and < 37.0 weeks), small for gestational age (SGA, birthweight of < 10th percentile), and placental malaria (defined as deposition of malaria pigment in the placenta with or without parasites) after different treatments of uncomplicated falciparum malaria were assessed by mixed-effects logistic regression, using artemether-lumefantrine, the most used antimalarial, as the reference standard. Registration PROSPERO: CRD42018104013.

RESULTS

Of the 22 eligible studies (n = 5015), IPD from16 studies were shared, representing 95.0% (n = 4765) of the women enrolled in literature. Malaria treatment in this pooled analysis mostly occurred in the second (68.4%, 3064/4501) or third trimester (31.6%, 1421/4501), with gestational age confirmed by ultrasound in 91.5% (4120/4503). Quinine (n = 184) and five commonly used artemisinin-based combination therapies (ACTs) were included: artemether-lumefantrine (n = 1087), artesunate-amodiaquine (n = 775), artesunate-mefloquine (n = 965), and dihydroartemisinin-piperaquine (n = 837). The overall pooled proportion of stillbirth was 1.1% (84/4361), PTB 10.0% (619/4131), SGA 32.3% (1007/3707), and placental malaria 80.1% (2543/3035), and there were no significant differences of considered outcomes by ACT. Higher parasitaemia before treatment was associated with a higher risk of SGA (adjusted odds ratio [aOR] 1.14 per 10-fold increase, 95% confidence interval [CI] 1.03 to 1.26, p = 0.009) and deposition of malaria pigment in the placenta (aOR 1.67 per 10-fold increase, 95% CI 1.42 to 1.96, p < 0.001).

CONCLUSIONS

The risks of stillbirth, PTB, SGA, and placental malaria were not different between the commonly used ACTs. The risk of SGA was high among pregnant women infected with falciparum malaria despite treatment with highly effective drugs. Reduction of malaria-associated adverse birth outcomes requires effective prevention in pregnant women.

Determination of piperaquine concentration in human plasma and the correlation of capillary versus venous plasma concentrations

Background

A considerable challenge in quantification of the antimalarial piperaquine in plasma is carryover of analyte signal between assays. Current intensive pharmacokinetic studies often rely on the merging of venous and capillary sampling. Drug levels in capillary plasma may be different from those in venous plasma, Thus, correlation between capillary and venous drug levels needs to be established.

Methods

Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was used to develop the method. Piperaquine was measured in 205 pairs of capillary and venous plasma samples collected simultaneously at ≥24hr post dose in children, pregnant women and non-pregnant women receiving dihydroartemisinin-piperaquine as malaria chemoprevention. Standard three-dose regimen over three days applied to all participants with three 40mg dihydroartemisinin/320mg PQ tablets per dose for adults and weight-based dose for children. Correlation analysis was performed using the program Stata® SE12.1. Linear regression models were built using concentrations or logarithm transformed concentrations and the final models were selected based on maximal coefficient of determination (R²) and visual check.

Results

An LC-MS/MS method was developed and validated, utilizing methanol as a protein precipitation agent, a Gemini C₁₈ column (50x2.0mm, 5μm) eluted with basic mobile phase solvents (ammonium hydroxide as the additive), and ESI⁺ as the ion source. This method had a calibration range of 10–1000 ng/mL and carryover was negligible. Correlation analysis revealed a linear relationship: C_cap = 1.04×C_ven+4.20 (R² = 0.832) without transformation of data, and lnC_cap = 1.01×lnC_ven+0.0125, (R² = 0.945) with natural logarithm transformation. The mean ratio (±SD) of C_cap/C_ven was 1.13±0.42, and median (IQR) was 1.08 (0.917, 1.33).

Conclusions

Capillary and venous plasma PQ measures are nearly identical overall, but not readily exchangeable due to large variation. Further correlation study accounting for disposition phases may be necessary.

Intermittent Preventive Treatment for Malaria in Pregnancy: Optimization of Target Concentrations of Dihydroartemisinin-Piperaquine

Background

Dihydroartemisinin-piperaquine (DHA-PQ) is highly efficacious as intermittent preventive therapy for malaria during pregnancy (IPTp). Determining associations between piperaquine (PQ) exposure, malaria risk, and adverse birth outcomes informs optimal dosing strategies.

Methods

Human immunodeficiency virus-uninfected pregnant women (n = 300) were enrolled in a placebo-controlled trial of IPTp at 12-20 weeks' gestation and randomized to sulfadoxine-pyrimethamine every 8 weeks, DHA-PQ every 8 weeks, or DHA-PQ every 4 weeks during pregnancy. Pharmacokinetic sampling for PQ was performed every 4 weeks, and an intensive pharmacokinetic substudy was performed in 30 women at 28 weeks' gestation. Concentration-effect relationships were assessed between exposure to PQ; the prevalence of Plasmodium falciparum infection during pregnancy; outcomes at delivery including placental malaria, low birth weight, and preterm birth; and risks for toxicity. Simulations of new dosing scenarios were performed.

Results

Model-defined PQ target venous plasma concentrations of 13.9 ng/mL provided 99% protection from P. falciparum infection during pregnancy. Each 10-day increase in time above target PQ concentrations was associated with reduced odds of placental parasitemia, preterm birth, and low birth weight, though increases in PQ concentrations were associated with QT interval prolongation. Modeling suggests that daily or weekly administration of lower dosages of PQ, compared to standard dosing, will maintain PQ trough levels above target concentrations with reduced PQ peak levels, potentially limiting toxicity.

Conclusions

The protective efficacy of IPTp with DHA-PQ was strongly associated with higher drug exposure. Studies of the efficacy and safety of alternative DHA-PQ IPTp dosing strategies are warranted.

Clinical Trials Registration

NCT02163447.

Comparison on simultaneous caillary and venous parasite density and genotyping results from children and adults with uncomplicated malaria: a prospective observational study in Uganda

BACKGROUND

Blood smear microscopy remains the gold-standard method to diagnose and quantify malaria parasite density. In addition, parasite genotyping of select loci is the most utilized method for distinguishing recrudescent and new infections and to determine the number of strains per sample. In research settings, blood may be obtained from capillary or venous compartments, and results from these matrices have been used interchangeably. Our aim was to compare quantitative results for parasite density and strain complexity from both compartments.

METHODS

In a prospective observational study, children and adults presenting with uncomplicated Plasmodium falciparum malaria, simultaneous capillary and venous blood smears and dried blood spots were collected over 42-days following treatment with artemether-lumefantrine. Blood smears were read by two microscopists, any discrepancies resolved by a third reader. Parasite DNA fingerprinting was conducted using six microsatellites. Bland Altman analysis and paired t-test/McNemar's test were used to assess the difference in density readings and measurements.

RESULTS

Two hundred twenty-three participants were included in the analysis (177 children (35 HIV-infected/142 HIV-uninfected), 21 HIV-uninfected pregnant women, and 25 HIV-uninfected non-pregnant adults). Parasite density measurements did not statistically differ between capillary and venous blood smears at the time of presentation, nor over the course of 42-day follow-up. Characterization of merozoite surface protein-2 (MSP-2) genetic polymorphism demonstrated a higher level of strain diversity at the time of presentation in venous samples, as compared with capillary specimens (p = 0.02). There was a high degree of variability in genotype-corrected outcomes when pairs of samples from each compartment were compared using MSP-2 alone, although the variability was reduced with the use of multiple markers.

CONCLUSIONS

Parasite density measurements do not statistically differ between capillary and venous compartments in all studied demographic groups at the time of presentation with malaria, or over the course of follow-up. More strains were detected by MSP-2 genotyping in venous samples than in capillary samples at the time of malaria diagnosis. The use of multiple polymorphic markers reduces the impact of variability in strain detection on genotype-corrected outcomes. This study confirms that both capillary and venous compartments can be used for sampling with confidence in the clinical research setting.

TRIAL REGISTRATION

The trial was registered at ClinicalTrials.gov under registration no. NCT01717885 .

Reduced Exposure to Piperaquine, Compared to Adults, in Young Children Receiving Dihydroartemisinin-Piperaquine as Malaria Chemoprevention

Dihydroartemisinin (DHA)-piperaquine is being evaluated as intermittent preventive therapy for malaria, but dosing has not been optimized for children. We assessed exposure to DHA and piperaquine in Ugandan children at two ages during infancy. Intensive sampling was performed in 32 children at 32 weeks of age, 31 children at 104 weeks, and 30 female adult controls. Compared with adults, DHA area under the concentration-time curve (AUC_{0-8 hr} ) was 52% higher at 32 weeks and comparable at 104 weeks. Compared with adults, piperaquine AUC_{0-21 d} was 35% lower at 32 weeks and 53% lower at 104 weeks. Terminal piperaquine concentrations on days 7, 14, and 21 were lower in children compared with adults and lower at 104 compared with 32 weeks. Piperaquine exposure was lower in young children compared with adults, and lower at 104 compared with 32 weeks of age, suggesting a need for age-based DHA-piperaquine dose optimization for chemoprevention.

Strong correlation of lumefantrine concentrations in capillary and venous plasma from malaria patients

Background

Lumefantrine is a long-acting antimalarial drug with an elimination half-life of over 3 days and protein binding of 99 percent. Correlation of lumefantrine concentrations from capillary plasma via fingerprick (C_c) versus venous plasma (C_v) remains to be defined.

Methods

Venous and capillary plasma samples were collected simultaneously from children, pregnant women, and non-pregnant adults at 2, 24, 120hr post last dose of a standard 3-day artemether-lumefantrine regimen they received for uncomplicated malaria. Some of the enrolled children and pregnant women were also HIV-infected. Samples were analyzed via liquid chromatography tandem mass spectrometry. Linear regression analysis was performed using the program Stata® SE12.1.

Results

In children, the linear regression equations for C_c vs C_v at 2, 24, and 120hr (day 7) post dose are [C_c] = 1.05*[C_v]+95.0 (n = 142, R² = 0.977), [C_c] = 0.995*[C_v]+56.7 (n = 147, R² = 0.990) and [C_c] = 0.958*[C_v]+18.6 (n = 139, R² = 0.994), respectively. For pregnant women, the equations are [C_c] = 1.04*[C_v]+68.1 (n = 43, R² = 0.990), [C_c] = 0.997*[C_v]+37.3 (n = 43, R² = 0.993) and [C_c] = 0.941*[C_v]+11.1 (n = 41, R² = 0.941), respectively. For non-pregnant adults, the equations are [C_c] = 1.05*[C_v]-117 (n = 32, R² = 0.958), [C_c] = 0.962*[C_v]+9.21 (n = 32, R² = 0.964) and [C_c] = 1.04*[C_v]-40.1 (n = 32, R² = 0.988), respectively. In summary, a linear relationship with a slope of ~1 was found for capillary and venous lumefantrine levels in children, pregnant women and non-pregnant adults at 2hr, 24hr and 120hr post last dose, representing absorption, distribution, and elimination phases.

Conclusions

Capillary and venous plasma concentration of lumefantrine can be used interchangeably at 1:1 ratio. Capillary sampling method via finger prick is a suitable alternative for sample collection in clinical studies.

Antiretroviral Therapy With Efavirenz Accentuates Pregnancy-Associated Reduction of Dihydroartemisinin-Piperaquine Exposure During Malaria Chemoprevention

Dihydroartemisinin (DHA)-piperaquine is promising for malaria chemoprevention in pregnancy. We assessed the impacts of pregnancy and efavirenz-based antiretroviral therapy on exposure to DHA and piperaquine in pregnant Ugandan women. Intensive sampling was performed at 28 weeks gestation in 31 HIV-uninfected pregnant women, in 27 HIV-infected pregnant women receiving efavirenz, and in 30 HIV-uninfected nonpregnant women. DHA peak concentration and area under the concentration time curve (AUC0-8hr ) were 50% and 47% lower, respectively, and piperaquine AUC0-21d was 40% lower in pregnant women compared to nonpregnant women. DHA AUC0-8hr and piperaquine AUC0-21d were 27% and 38% lower, respectively, in pregnant women receiving efavirenz compared to HIV-uninfected pregnant women. Exposure to DHA and piperaquine were lower among pregnant women and particularly in women on efavirenz, suggesting a need for dose modifications. The study of modified dosing strategies for these populations is urgently needed.

Oil-Fortified Maize Porridge Increases Absorption of Lumefantrine in Children with Uncomplicated Falciparum Malaria

Artemether-lumefantrine (AL) is a first-line treatment for uncomplicated malaria. Absorption of lumefantrine (LUM) is fat dependent, and in children, intake is recommended with milk. We investigated whether oil-fortified maize porridge can be an alternative when milk is not available. In an open-label pharmacokinetic study, Ugandan children <5 years with uncomplicated Plasmodium falciparum malaria were randomized to receive standard six-dose AL treatment [one tablet (20 mgA/120 mg LUM) if <15 kg and two tablets if >15 kg] with milk (A) or maize porridge plus oil (B). Parametric two-sample t-test was used to compare relative oral LUM bioavailability. The primary end-point was LUM exposure till 8 hr after the first dose (AUC_{0-8 hr} ). Secondary outcome included day 7 concentrations (d7_LUM ), LUM exposure between days 7 and 28 (AUC_d7-28 ) and day 28 PCR-adjusted parasitological response. Evaluable children (n = 33) included 16 in arm A and 17 in arm B. The AUC_{0-8 hr} was comparable between A and B [geometric mean (95% CI): 6.01 (3.26-11.1) versus 6.26 (4.5-8.43) hr*μg/mL, p = 0.9]. Less interindividual variability in AUC_{0-8 hr} was observed in B (p = 0.01), but d7_LUM and AUC_d7-28 were comparable. Children receiving two tablets had significantly higher exposure than those receiving one tablet [median d7_LUM (505 versus 289 ng/mL, p = 0.02) and AUC_d7-28 (108 versus 41 hr*μg/mL, p = 0.006)]. One parasitological failure (d28 recrudescence) was observed. Our findings suggest that oil-fortified maize porridge can be an alternative to milk in augmenting absorption of LUM. The lower LUM exposure observed in children dosed with one AL tablet needs further attention.

Parasite Clearance and Artemether Pharmacokinetics Parameters Over the Course of Artemether-Lumefantrine Treatment for Malaria in Human Immunodeficiency Virus (HIV)-Infected and HIV-Uninfected Ugandan Children

Background.

Artemisinins are primarily responsible for initial parasite clearance. Antimalarial pharmacokinetics (PK), human immunodeficiency virus (HIV) infection, and antiretroviral therapy have been shown to impact treatment outcomes, although their impact on early parasite clearance in children has not been well characterized.

Methods.

Parasite clearance parameters were generated from twice-daily blood smears in HIV-infected and HIV-uninfected Ugandan children treated with artemether-lumefantrine (AL). Artemether and dihydroartemisinin (DHA) area-under-the-curve from 0–8 hours (AUC_0-8hr) after the 1st AL dose was compared with AUC_0-8hr after the last (6th) dose in a concurrently enrolled cohort. The association between post-1st dose artemisinin AUC_0-8hr and parasite clearance was assessed.

Results.

Parasite clearance was longer in HIV-infected versus HIV-uninfected children (median, 3.5 vs 2.8 hours; P = .003). Artemether AUC_0-8hr was 3- to 4-fold lower after the 6th dose versus the 1st dose of AL in HIV-infected children on nevirapine- or lopinavir/ritionavir-based regimens and in HIV-uninfected children (P ≤ .002, 1st vs 6th-dose comparisons). Children on efavirenz exhibited combined post-1st dose artemether/DHA exposure that was significantly lower than those on lopinavir/ritonavir and HIV-uninfected children. Multiple regression analysis supported that the effect of artemether/DHA exposure on parasite clearance was significantly moderated by HIV status.

Conclusions.

Parasite clearance rates remain rapid in Uganda and were not found to associate with PK exposure. However, significant decreases in artemisinin PK with repeated dosing in nearly all children, coupled with small, but significant increase in parasite clearance half-life in those with HIV, may have important implications for AL efficacy, particularly because reports of artemisinin resistance are increasing.

Antiretroviral Choice for HIV Impacts Antimalarial Exposure and Treatment Outcomes in Ugandan Children

Pharmacokinetic/pharmacodynamic studies of artemether-lumefantrine and 3 antiretroviral regimens were conducted in malaria-infected Ugandan children. Efavirenz-based treatment was associated with significant reductions in antimalarial exposure and higher risks of recurrent malaria. Caution in their concurrent use is warranted.

Background. The optimal treatment of malaria in human immunodeficiency virus (HIV)–infected children requires consideration of critical drug–drug interactions in coinfected children, as these may significantly impact drug exposure and clinical outcomes.

Methods. We conducted an intensive and sparse pharmacokinetic/pharmacodynamic study in Uganda of the most widely adopted artemisinin-based combination therapy, artemether-lumefantrine. HIV-infected children on 3 different first-line antiretroviral therapy (ART) regimens were compared to HIV-uninfected children not on ART, all of whom required treatment for Plasmodium falciparum malaria. Pharmacokinetic sampling for artemether, dihydroartemisinin, and lumefantrine exposure was conducted through day 21, and associations between drug exposure and outcomes through day 42 were investigated.

Results. One hundred forty-five and 225 children were included in the intensive and sparse pharmacokinetic analyses, respectively. Compared with no ART, efavirenz (EFV) reduced exposure to all antimalarial components by 2.1- to 3.4-fold; lopinavir/ritonavir (LPV/r) increased lumefantrine exposure by 2.1-fold; and nevirapine reduced artemether exposure only. Day 7 concentrations of lumefantrine were 10-fold lower in children on EFV vs LPV/r-based ART, changes that were associated with an approximate 4-fold higher odds of recurrent malaria by day 28 in those on EFV vs LPV/r-based ART.

Conclusions. The choice of ART in children living in a malaria-endemic region has highly significant impacts on the pharmacokinetics and pharmacodynamics of artemether-lumefantrine treatment. EFV-based ART reduces all antimalarial components and is associated with the highest risk of recurrent malaria following treatment. For those on EFV, close clinical follow-up for recurrent malaria following artemether-lumefantrine treatment, along with the study of modified dosing regimens that provide higher exposure, is warranted.

Prevalence of sexual coercion and its association with unwanted pregnancies among young pregnant females in Kampala, Uganda: a facility based cross-sectional study

BACKGROUND

Sexual coercion is associated with sexually transmitted infections and unwanted pregnancies with consequential unsafe abortions and increased maternal morbidity and mortality. Current literature focuses mainly on its risk factors but less on its resultant deleterious health effects. We conducted a study to determine the prevalence of sexual coercion and its association with unwanted pregnancies among young pregnant women.

METHODS

In a cross-sectional study, four hundred and sixteen (416) consenting pregnant females aged 15-24 years attending antenatal clinics in Lubaga division Kampala district in Uganda were enrolled using systematic sampling. Quantitative and qualitative data on sexual coercion were collected by female interviewers. Adjusted Prevalence Proportion Ratios (Adj. PPRs) of unwanted pregnancy and associated 95 % confidence intervals were estimated by generalized linear models with log link function and Poisson family distribution using robust variance estimator. Quantitative data were analyzed using Stata version 10.0, while qualitative data were analyzed using manifest content analysis.

RESULTS

Prevalence of sexual coercion was 24 % and was higher among those who had non consensual sexual debut (29.0 %) compared with those who had consensual sexual debut (22.6 %). The prevalence of unwanted pregnancy was 18.3 % and was higher among participants who had been sexually coerced relative to their counterparts (p < 0.001). History of sexual coercion in the past 12 months and non consensual sexual debut were associated with unwanted pregnancy [adj.PPR = 2.23, 95 % CI: (1.49-3.32)] and 1.72, 95 % CI: (1.16- 2.54)] respectively. Qualitative results indicated that different forms/contexts of sexual coercion, such as deception, transactional sex and physical force influenced unwanted pregnancies.

DISCUSSION

This study highlights that a quarter of our participants in our quantitative study had experienced sexual coercion in the past twelve months and nearly a third of these, had history of non consensual sexual debut. Unwanted pregnancy was higher among the sexually coerced and those who had non consensual sexual debut.

CONCLUSION

Sexual coercion among pregnant women aged 15-24 years in Kampala, Uganda is high and is significantly associated with unwanted pregnancy. Comprehensive sex education targeting young people (<25 years), along with availability and access to youth friendly centers may be useful in addressing sexual coercion and its negative outcomes.

Home management of malaria with artemether-lumefantrine compared with standard care in urban Ugandan children: a randomised controlled trial

BACKGROUND

Home management of malaria-the presumptive treatment of febrile children with antimalarial drugs-is advocated to ensure prompt effective treatment of the disease. We assessed the effect of home delivery of artemether-lumefantrine on the incidence of antimalarial treatment and on clinical outcomes in children from an urban setting with fairly low malaria transmission.

METHODS

In Kampala, Uganda, 437 children aged between 1 and 6 years from 325 households were randomly assigned by a computer-generated sequence to receive home delivery of prepackaged artemether-lumefantrine for presumptive treatment of febrile illnesses (n=225) or current standard of care (n=212). Randomisation was done by household after a pilot period of 1 month. After randomisation, study participants were followed up for an additional 12 months and information on their health and treatment of illnesses was obtained by use of monthly questionnaires and household diaries, which were completed by the participants' carers. The primary outcome was treatment incidence density per person-year. Analysis of the primary outcome was done on the modified intention-to-treat population, which included all participants apart from those excluded before data collection. This trial is registered with ClinicalTrials.gov, number NCT00115921.

FINDINGS

Eight participants in the home management group and four in the standard care group were excluded before data collection; therefore, the primary analysis was done in 217 and 208 participants, respectively. The home management group received nearly twice the number of antimalarial treatments as the standard care group (4.66 per person-year vs 2.53 per person-year; incidence rate ratio [IRR] 1.72, 95% CI 1.43-2.06, p<0.0001), and nearly five times the number given to children with microscopically confirmed malaria in a comparable cohort of children (4.66 per person-year vs 1.03 per person-year, IRR 5.19, 95% CI 4.24-6.35, p<0.0001). Clinical data were available for 189 children in the home management group and 176 in the control group at study end; the main reasons for exclusion were movement out of the study area or loss to follow-up. The proportion of participants with parasitaemia at final assessment in the intervention group was lower than in the control group (four [2%] vs 17 [10%], p=0.006), but there were no other differences in standard malariometric indices, including anaemia. Serious adverse events were captured retrospectively. One child died in each group (home management-severe pneumonia and possible septicaemia; standard care-presumed respiratory failure).

INTERPRETATION

Although home management of malaria led to prompt treatment of fever, there was little effect on clinical outcomes. The substantial over-treatment suggests that artemether-lumefantrine provided in the home might not be appropriate for large urban areas or settings with fairly low malaria transmission.

FUNDING

Gates Malaria Partnership.

Pharmacovigilance of antimalarial treatment in Uganda: community perceptions and suggestions for reporting adverse events

OBJECTIVES

The deployment of new antimalarials in Africa provides an important opportunity to develop systems for pharmacovigilance. To inform strategies for reporting adverse events in Uganda, we investigated local perceptions and experiences with antimalarial treatment, and evaluated existing and potential systems for pharmacovigilance.

METHODS

Focus group discussions (FGD) were conducted with community members and health workers from urban and rural Uganda exploring knowledge of fever/malaria, perceptions and expectations of treatment, understanding of adverse effects, and experiences with adverse events. Sessions were recorded, transcribed into English, and analysed using a coding scheme developed from pre-defined topics together with themes emerging from the data.

RESULTS

Between April and July 2006, we conducted 25 FGDs; 16 with community members and nine with health workers. All respondents had extensive experience with malaria and its treatment. Community members commonly recognized adverse effects of antimalarial therapy. However, events were uncommonly reported, and certain events were often interpreted as signs of successful treatment. Community members often felt that the costs of reporting or seeking additional care outweighed the potential benefits. Health workers were unfamiliar with formal pathways for reporting, and were deterred by the additional work of reporting and fear of incrimination. Respondents provided suggestions for incentives and methods of reporting, emphasizing that pharmacovigilance should ideally encompass the public and private sector, and the community.

CONCLUSIONS

To be successful, pharmacovigilance relying on voluntary reporting will require active participation of patients and health workers. Addressing the costs and benefits of reporting, and providing sensitization, training and feedback will be important.