Tenofovir for prevention of mother to child transmission of hepatitis B in migrant women in a resource-limited setting on the Thailand-Myanmar border: a commentary on challenges of implementation

BACKGROUND:The aim of this manuscript is to highlight challenges in the implementation of maternal tenofovir disoproxil fumarate (tenofovir) for prevention of mother to child transmission (PMTCT) of hepatitis B virus (HBV) in resource limited setting. Current preventive strategies in resource-limited settings fail mainly due to prohibitive costs of hepatitis B immunoglobulin (HBIG) and a high proportion of homebirths, meaning both HBIG and hepatitis B birth dose vaccine are not given. A new strategy for PMTCT without the necessity of HBIG, could be daily tenofovir commenced early in gestation. Implementation challenges to early tenofovir for PMTCT can provide insight to elimination strategies of HBV as the burden of disease is high in resource-limited settings. METHODS:Challenges encountered during implementation of a study of tenofovir for PMTCT before 20 weeks gestation in rural and resource-limited areas on the Thailand-Myanmar border were identified informally from trial study logbooks and formally from comments from patients and staff at monthly visits. ClinicalTrials.gov Identifier: NCT02995005. MAIN BODY:During implementation 171 pregnant women were hepatitis B surface antigen (HBsAg) positive by point of-care test over 19 months (May-2018 until Dec-2019). In this resource-limited setting where historically no clinic has provided tenofovir for PMTCT of HBV, information provided by staff resulted in a high uptake of study screening (95.5% (84/88) when offered to pregnant women. False positive point-of-care rapid tests hinder a test and treat policy for HBV and development of improved rapid tests that include HBeAg and/or HBV DNA would increase efficiency. Integrated care of HBV to antenatal care, transport assistance and local agreements to facilitate access, could increase healthcare at this critical stage of the life course. As safe storage of medication in households in resource-limited setting may not be ideal, interactive counseling about this must be a routine part of care. CONCLUSION:Despite challenges, results from the study to date suggest tenofovir can be offered to HBV-infected women in resource-limited settings before 20 weeks gestation with a high uptake of screening, high drug accountability and follow-up, with provision of transportation support. This commentary has highlighted practical implementation issues with suggestions for strategies that support the objective of PMTCT and the World Health Organization goal of HBV elimination by 2030

Challenges of implementing tenofovir disoproxil fumarate in pregnancy for prevention of hepatitis B mother to child transmission in a rural population

Background: Hepatitis B is highly endemic in south-east Asia with the most common route of transmission being from mother to child. In rural settings, current preventive strategies with hepatitis B immunoglobulins and vaccinations fail due to costs, need for cold chain, homebirths, and transportation difficulties. A new strategy for prevention of mother to child transmission (PMTCT) could be early (<20 weeks gestation) daily tenofovir disoproxil fumarate (TDF), a potent antiviral agent that is safe in pregnancy. Assessment of barriers to early TDF for PMTCT-Hep B is important before possible implementation. Methods & Materials: Narrative and visual review of start-up challenges encountered during implementation of a study of TDF for PMTCT before 20 weeks gestation in rural areas on the Thailand-Myanmar border. ClinicalTrials.gov Identifier: NCT02995005. Results: Major challenges of implementation from June 2018 to September 2019 included: gestation of pregnancy at presentation, point-of-care (POC)-testing reliability, tablet storage and handling. Overall, 156 women tested positive for HBsAg by Rapid Diagnostic Test (RDT) POC-testing but late presentation (≥20 weeks) was common: 53% (83/156). In women <20 weeks gestation with positive-HBsAg, consent for study screening was 89.0% (65/73). Exclusion after RDT-testing was 21.5% (14/65): three had a negative HBsAg at confirmation, nine had an undetectable viral load, two had elevated phosphate levels. Daily ambient temperatures were high: only 3/365 days (0.8%) were within manufacturer recommended TDF storage temperatures (20–25 °C), and for 187 days of the year the temperature was 30 °C. Drug accountability was high but one in 10 of the women reported incidents of tablet misplacement: “pills dropped though the [bamboo] floor and fell in the mud”, “children played with the bottle”. Financial support of transportation resulted in follow-up rates of 84.3% (43/51) attending all of the expected appointments. The missed appointments were highest in rainy season when the rivers become impassable, 62.5% (5/8). Conclusion: Improved public awareness of the benefits or early antenatal care, better RDT-tests, and confirmation of TDF bioavailability at higher ambient temperatures, are important in the rural tropics for prevention of mother to child transmission for hepatitis B programs

Tenofovir for prevention of mother to child transmission of hepatitis B in migrant women in a resource-limited setting on the Thailand-Myanmar border: a commentary on challenges of implementation

BACKGROUND: The aim of this manuscript is to highlight challenges in the implementation of maternal tenofovir disoproxil fumarate (tenofovir) for prevention of mother to child transmission (PMTCT) of hepatitis B virus (HBV) in resource limited setting. Current preventive strategies in resource-limited settings fail mainly due to prohibitive costs of hepatitis B immunoglobulin (HBIG) and a high proportion of homebirths, meaning both HBIG and hepatitis B birth dose vaccine are not given. A new strategy for PMTCT without the necessity of HBIG, could be daily tenofovir commenced early in gestation. Implementation challenges to early tenofovir for PMTCT can provide insight to elimination strategies of HBV as the burden of disease is high in resource-limited settings. METHODS: Challenges encountered during implementation of a study of tenofovir for PMTCT before 20 weeks gestation in rural and resource-limited areas on the Thailand-Myanmar border were identified informally from trial study logbooks and formally from comments from patients and staff at monthly visits. ClinicalTrials.gov Identifier: NCT02995005. MAIN BODY: During implementation 171 pregnant women were hepatitis B surface antigen (HBsAg) positive by point of-care test over 19 months (May-2018 until Dec-2019). In this resource-limited setting where historically no clinic has provided tenofovir for PMTCT of HBV, information provided by staff resulted in a high uptake of study screening (95.5% (84/88) when offered to pregnant women. False positive point-of-care rapid tests hinder a test and treat policy for HBV and development of improved rapid tests that include HBeAg and/or HBV DNA would increase efficiency. Integrated care of HBV to antenatal care, transport assistance and local agreements to facilitate access, could increase healthcare at this critical stage of the life course. As safe storage of medication in households in resource-limited setting may not be ideal, interactive counseling about this must be a routine part of care. CONCLUSION: Despite challenges, results from the study to date suggest tenofovir can be offered to HBV-infected women in resource-limited settings before 20 weeks gestation with a high uptake of screening, high drug accountability and follow-up, with provision of transportation support. This commentary has highlighted practical implementation issues with suggestions for strategies that support the objective of PMTCT and the World Health Organization goal of HBV elimination by 2030

Electrocardiographic effects of four antimalarials for pregnant women with uncomplicated malaria on the Thailand-Myanmar border: A randomised controlled trial

Quinoline antimalarials cause drug-induced electrocardiograph QT prolongation, a potential risk factor for torsade de pointes. The effects of currently used antimalarials on the electrocardiogram were assessed in pregnant women with malaria. Pregnant women with microscopy-confirmed parasitaemia of any malaria species were enrolled in an open-label randomised controlled trial on the Thailand-Myanmar border in 2010–2016. Patients were randomised to the standard regimen dihydroartemisinin-piperaquine (DP), artesunate-mefloquine (ASMQ), or an extended regimen of artemether-lumefantrine (AL+). Recurrent vivax infections were treated with chloroquine. Standard 12-lead electrocardiograms were assessed on day 0, 4-6 hour following the last dose and day 7. QT was corrected for the heart rate by a linear mixed-effects model derived population-based correction formula (QTcP = QT/RR0.381). A total of 86 AL+, 82 ASMQ, 88 DP and 21 chloroquine treated episodes were included. No patients had an uncorrected QT interval nor QTcP > 480ms at any time. QTcP corresponding to peak drug concentration was longer in DP group (adjusted predicted mean difference 17.84 ms, 95% CI 11.58 to 24.10, p<0.001) and chloroquine group (18.31 ms, 95% CI 8.78 to 27.84, p<0.001) than in the AL+ group, but not different in the ASMQ group (2.45 ms, 95% CI -4.20 to 9.10, p=0.47). There was no difference between DP and chloroquine (p=0.91). QTc prolongation resulted mainly from widening of JT interval. In pregnant women, none of the antimalarial drug treatments exceeded conventional thresholds for an increased risk of torsade de pointes

Determinants of primaquine and carboxyprimaquine exposures in children and adults with Plasmodium vivax malaria

Background Primaquine is the only widely available drug for radical cure of Plasmodium vivax malaria. There is uncertainty whether the pharmacokinetic properties of primaquine are altered significantly in childhood or not. Methods Glucose-6-phosphate dehydrogenase normal patients with uncomplicated P. vivax malaria were randomized to receive either chloroquine (25mg base/kg) or dihydroartemisinin-piperaquine (dihydroartemisinin 7mg/kg and piperaquine 55mg/kg) plus primaquine; given either as 0.5 mg base/kg/day for 14 days or 1 mg/kg/day for 7 days. Pre-dose day 7 venous plasma concentrations of chloroquine, desethylchloroquine, piperaquine, primaquine and carboxyprimaquine were measured. Methemoglobin levels were measured on day 7. Results Day 7 primaquine and carboxyprimaquine concentrations were available for 641 patients. After adjustment for the primaquine mg/kg daily dose, day of sampling, partner drug, and fever clearance, there was a significant non-linear relationship between age and trough primaquine and carboxyprimaquine concentrations, and day methemoglobin levels. Compared to adults 30 years of age, children 5 years of age had trough primaquine concentrations 0.53 (95% CI: 0.39- 0.73) fold lower, trough carboxyprimaquine concentrations 0.45 (95% CI: 0.35- 0.55) fold lower, and day 7 methemoglobin levels 0.87 (95% CI: 0.58-1.27) fold lower. Increasing concentrations of piperaquine and chloroquine and poor metabolizer CYP 2D6 alleles were associated with higher day 7 primaquine and carboxyprimaquine concentrations. Higher blood methemoglobin concentrations were associated with a lower risk of recurrence. Conclusion Young children have lower primaquine and carboxyprimaquine exposures, and lower levels of methemoglobinemia, than adults. Young children may need higher weight adjusted primaquine doses than adults

Chloroquine versus hihydroartemisinin-piperaquine with standard high-dose Primaquine given either for 7 days or 14 days in Plasmodium vivax malaria

Background: Primaquine is necessary for the radical cure of Plasmodium vivax malaria, but the optimum duration of treatment and best partner drug are uncertain. A randomized controlled trial was performed to compare the tolerability and radical curative efficacy of 7-day versus 14-day high-dose primaquine regimens (total dose 7mg/kg) with either chloroquine or dihydroartemisinin-piperaquine.Methods: Patients with uncomplicated P. vivax malaria on the Thailand-Myanmar border were randomized to either chloroquine (25mg base/kg) or dihydroartemisinin-piperaquine (dihydroartemisinin 7mg/kg and piperaquine 55mg/kg) plus primaquine, either 0.5 mg/kg/day for 14 days or 1 mg/kg/day for 7 days. Adverse events within 42 days and 1-year recurrence rates were compared and their relationship with day 6 drug concentrations assessed.Results: Between February 2012 and July 2014, 680 patients were enrolled. P. vivax recurrences (all after day 35) occurred in 80/654 (12%) patients; there was no difference between treatments. Compared to the 7-day primaquine groups the pooled relative risk of recurrence in the 14-day groups was 1.15 (95% confidence interval 0.7 to 1.8). Hematocrit reductions were clinically insignificant except in G6PD female heterozygotes, 2 of whom had hematocrit reductions to &lt;23% requiring blood transfusion.Conclusion: Radical cure should be deployed more widely. The radical curative efficacy in vivax malaria of 7-day high-dose primaquine is similar to the standard 14-day high-dose regimen. Chloroquine and dihydroartemisinin-piperaquine are both highly effective treatments of the blood stage infection. Quantitative point of care G6PD testing would ensure safe use of the 7-day high-dose primaquine regimen in G6PD heterozygous females.</br

Chloroquine versus hihydroartemisinin-piperaquine with standard high-dose Primaquine given either for 7 days or 14 days in Plasmodium vivax malaria

Background: Primaquine is necessary for the radical cure of Plasmodium vivax malaria, but the optimum duration of treatment and best partner drug are uncertain. A randomized controlled trial was performed to compare the tolerability and radical curative efficacy of 7-day versus 14-day high-dose primaquine regimens (total dose 7mg/kg) with either chloroquine or dihydroartemisinin-piperaquine.Methods: Patients with uncomplicated P. vivax malaria on the Thailand-Myanmar border were randomized to either chloroquine (25mg base/kg) or dihydroartemisinin-piperaquine (dihydroartemisinin 7mg/kg and piperaquine 55mg/kg) plus primaquine, either 0.5 mg/kg/day for 14 days or 1 mg/kg/day for 7 days. Adverse events within 42 days and 1-year recurrence rates were compared and their relationship with day 6 drug concentrations assessed.Results: Between February 2012 and July 2014, 680 patients were enrolled. P. vivax recurrences (all after day 35) occurred in 80/654 (12%) patients; there was no difference between treatments. Compared to the 7-day primaquine groups the pooled relative risk of recurrence in the 14-day groups was 1.15 (95% confidence interval 0.7 to 1.8). Hematocrit reductions were clinically insignificant except in G6PD female heterozygotes, 2 of whom had hematocrit reductions to <23% requiring blood transfusion.Conclusion: Radical cure should be deployed more widely. The radical curative efficacy in vivax malaria of 7-day high-dose primaquine is similar to the standard 14-day high-dose regimen. Chloroquine and dihydroartemisinin-piperaquine are both highly effective treatments of the blood stage infection. Quantitative point of care G6PD testing would ensure safe use of the 7-day high-dose primaquine regimen in G6PD heterozygous females