Exposure to artemether-lumefantrine (Coartem) in first trimester pregnancy in an observational study in Zambia

Safety of Treating Malaria with Artemisinin-Based Combination Therapy in the First Trimester of Pregnancy

There have been recent calls for the use of artemisinin-based combination therapies (ACTs) for uncomplicated malaria in the first trimester of pregnancy. Nevertheless, the 2021 WHO Guidelines for Malaria reaffirmed their position that there is not adequate clinical safety data on artemisinins to support that usage. The WHO's position is consistent with several issues with the existing clinical data. First, first trimester safety results from multiple ACTs were lumped in a meta-analysis which does not demonstrate that each of the included ACTs is equally safe. Second, safety results from all periods of the first trimester were lumped in the meta-analysis which does not demonstrate the same level of safety for all subperiods, particularly gestational Weeks 6 to 8 which is likely to be the most sensitive period. Third, even if there is evidence of a lack of an effect on miscarriage for a particular ACT, it does not follow then there are no developmental effects for any ACT. In monkeys, artesunate caused marked embryonal anemia leading to embryo death but the long-term consequences of lower levels of embryonal anemia are not known. Fourth, there have been advances in the sensitivity and usage of rapid diagnostic tests that will lead to diagnoses of malaria earlier in gestation which is less well studied and more likely sensitive to artemisinins. Any clinical studies of the safety of ACTs in the first trimester need to evaluate the results of treatment with individual ACTs during different 1- to 2-week periods of the first trimester.

The Changing Global Landscape in the Development of Artemisinin-Based Treatments: A Clinical Trial Perspective

Artemisinin and its derivatives (ARTs), due to their potent antimalarial activities, are widely used as frontline antimalarials across the world. Although the large-scale deployment of ARTs has significantly contributed to a substantial decline in malaria deaths, the global malaria burden is still high. New antimalarial treatments need to be developed to manage the growing artemisinin resistance. Understanding the status of ART development is crucial for developing strategies for new alternatives and identifying opportunities to develop ART-based treatments. This study sampled ART clinical trials from the past two decades to gain an overview of the global ART-development landscape. A total of 768 trials were collected to analyze the disease focuses, activity trends, development status, geographic distribution, and combination treatment profiles of ART trials. The findings highlighted the constant focus of ARTs on malaria, the evolving combination research focus, the distinctions between ART development preferences across global regions, the urgent demands for treatments for artemisinin-resistant malaria, and the unavoidable need to consider ART combinations in the development of new antimalarials.

Drug treatment and prevention of malaria in pregnancy: a critical review of the guidelines

Background

Malaria caused by Plasmodium falciparum in pregnancy can result in adverse maternal and fetal sequelae. This review evaluated the adherence of the national guidelines drawn from World Health Organization (WHO) regions, Africa, Eastern Mediterranean, Southeast Asia, and Western Pacific, to the WHO recommendations on drug treatment and prevention of chloroquine-resistant falciparum malaria in pregnant women.

Methods

Thirty-five updated national guidelines and the President’s Malaria Initiative (PMI), available in English language, were reviewed. The primary outcome measures were the first-line anti-malarial treatment protocols adopted by national guidelines for uncomplicated and complicated falciparum malaria infections in early (first) and late (second and third) trimesters of pregnancy. The strategy of intermittent preventive treatment of malaria in pregnancy (IPTp) with sulfadoxine-pyrimethamine (SP) was also addressed.

Results

This review evaluated the treatment and prevention of falciparum malaria in pregnancy in 35 national guidelines/PMI-Malaria Operational Plans (MOP) reports out of 95 malaria-endemic countries. Of the 35 national guidelines, 10 (28.6%) recommend oral quinine plus clindamycin as first-line treatment for uncomplicated malaria in the first trimester. As the first-line option, artemether–lumefantrine, an artemisinin-based combination therapy, is adopted by 26 (74.3%) of the guidelines for treating uncomplicated or complicated malaria in the second and third trimesters. Intravenous artesunate is approved by 18 (51.4%) and 31 (88.6%) guidelines for treating complicated malaria during early and late pregnancy, respectively. Of the 23 national guidelines that recommend IPTp-SP strategy, 8 (34.8%) are not explicit about directly observed therapy requirements, and three-quarters, 17 (73.9%), do not specify contra-indication of SP in human immunodeficiency virus (HIV)-infected pregnant women receiving cotrimoxazole prophylaxis. Most of the guidelines (18/23; 78.3%) state the recommended folic acid dose.

Conclusion

Several national guidelines and PMI reports require update revisions to harmonize with international guidelines and emergent trends in managing falciparum malaria in pregnancy. National guidelines and those of donor agencies should comply with those of WHO guideline recommendations although local conditions and delayed guideline updates may call for deviations from WHO evidence-based guidelines.

Teratogen update: Malaria in pregnancy and the use of antimalarial drugs in the first trimester

Malaria is a particular problem in pregnancy because of enhanced sensitivity, the possibility of placental malaria, and adverse effects on pregnancy outcome. Artemisinin-containing combination therapies (ACTs) are the most effective antimalarials known. WHO recommends 7-day quinine therapy for uncomplicated Plasmodium falciparum malaria in the first trimester despite the superior tolerability and efficacy of 3-day ACT regimens because artemisinins caused embryolethality and/or cardiovascular malformations at relatively low doses in rats, rabbits, and monkeys. The developmental toxicity of artesunate, artemether, and DHA were similar in rats but artesunate was embryotoxic at lower doses in rabbits (5 mg/kg/day) than artemether (no effect level = 25 mg/kg/day). In clinical studies in Africa, treatment with artemether-lumefantrine in the first trimester was observed to be highly efficacious and the miscarriage rate (≤3.1%) was similar to no antimalarial treatment (2.6%). When data from the first-trimester use of largely artesunate-based therapies in Thailand were pooled together, there was no difference in miscarriage rate compared to quinine. However, individually, artesunate-mefloquine was associated with a higher miscarriage rate (15/71 = 21%) compared to other artemisinin-based therapies including 7-day artesunate + clindamycin (2/50 = 4%) and quinine (92/842 = 11%). Thus, appropriate statistical comparisons of individual ACT groups are needed prior to assuming that they all have the same risk for developmental toxicity. Current limitations in the assessment of the safety of ACTs in the first trimester are a lack of exposures early in gestation (gestational weeks 6-7), limited postnatal evaluation for cardiovascular malformations, and the pooling of all ACTs for the assessment of risk.

Safety of Artemisinin Derivatives in the First Trimester of Pregnancy: A Controversial Story

Artemisinin combination therapy (ACT) is recommended by the World Health Organization (WHO) as first line treatment for uncomplicated malaria both in adults and children. During pregnancy, ACT is considered safe only in the second and third trimester, since animal studies have demonstrated that artemisinin derivatives can cause foetal death and congenital malformation within a narrow time window in early embryogenesis. During this period, artemisinin derivatives induce defective embryonic erythropoiesis and vasculogenesis/angiogenesis in experimental models. However, clinical data on the safety profile of ACT in pregnant women have not shown an increased risk of miscarriage, stillbirth, or congenital malformation, nor low birth weight, associated with exposure to artemisinins in the first trimester. Although further studies are needed, the evidence collected up to now is prompting the WHO towards a change in the guidelines for the treatment of uncomplicated malaria, allowing the use of ACT also in the first trimester of pregnancy.

Usefulness of day 7 lumefantrine plasma concentration as a predictor of malaria treatment outcome in under-fives children treated with artemether-lumefantrine in Tanzania

Background

Day 7 plasma lumefantrine concentration is suggested as a predictor for malaria treatment outcomes and a cut-off of ≥ 200 ng/ml is associated with day 28 cure rate in the general population. However, day 7 lumefantrine plasma concentration can be affected by age, the extent of fever, baseline parasitaemia, and bodyweight. Therefore, this study assessed the usefulness of day 7 lumefantrine plasma concentration as a predictor of malaria treatment outcome in under-fives children treated with generic or innovator drug-containing artemether-lumefantrine (ALu) in Tanzania.

Methods

This study was nested in an equivalence prospective study that aimed at determining the effectiveness of a generic ALu (Artefan^®) in comparison with the innovator’s product (Coartem^®). Children with uncomplicated malaria aged 6–59 months were recruited and randomized to receive either generic or innovator’s product. Children were treated with ALu as per World Health Organization recommendations. The clinical and parasitological outcomes were assessed after 28 days of follow up. PCR was performed to distinguish recrudescence and re-infections among children with recurrent malaria. Analysis of day 7 lumefantrine plasma concentration was carried out using a high-performance liquid chromatographic method with UV detection.

Results

The PCR corrected cure rates were 98.7% for children treated with generic and 98.6% for those treated with the innovator product (p = 1.00). The geometric mean (± SD) of day 7 plasma lumefantrine concentration was 159.3 (± 2.4) ng/ml for the generic and 164 (± 2.5) ng/ml for the innovator groups, p = 0.87. Geometric mean (± SD) day 7 lumefantrine plasma concentration between cured and recurrent malaria was not statistically different in both treatment arms [158.5 (± 2.4) vs 100.0 (± 1.5) ng/ml, (p = 0.28) for generic arm and 158.5 (± 2.3) vs 251.2 (± 4.2) ng/ml, (p = 0.24) for innovator arm]. Nutritional status was found to be a determinant of recurrent malaria (adjusted hazardous ratio (95% confidence interval) = 3(1.1–8.2), p = 0.029.

Conclusion

Using the recommended cut-off point of ≥ 200 ng/ml, day 7 plasma lumefantrine concentration failed to predict malaria treatment outcome in children treated with ALu in Tanzania. Further studies are recommended to establish the day 7 plasma lumefantrine concentration cut-off point to predict malaria treatment outcome in children.

Antimalarial drugs for treating and preventing malaria in pregnant and lactating women

INTRODUCTION

Malaria in pregnancy and postpartum cause maternal mortality and adverse fetal outcomes. Efficacious and safe antimalarials are needed to treat and prevent such serious consequences. However, because of the lack of evidence on fetal safety, quinine, an old and less efficacious drug has long been recommended for pregnant women. Uncertainty about safety in relation to breastfeeding leads to withholding of efficacious treatments postpartum or cessation of breastfeeding. Areas covered: A search identified literature on humans in three databases (MEDLINE, Embase and Global health) using pregnancy or lactation, and the names of antimalarial drugs as search terms. Adverse reactions to the mother, fetus or breastfed infant were summarized together with efficacies. Expert opinion: Artemisinins are more efficacious and well-tolerated than quinine in pregnancy. Furthermore, the risks of miscarriage, stillbirth or congenital abnormality were not higher in pregnancies exposed to artemisinin derivatives for treatment of malaria than in pregnancies exposed to quinine or in the comparable background population unexposed to any antimalarials, and this was true for treatment in any trimester. Assessment of safety and efficacy of antimalarials including dose optimization for pregnant women is incomplete. Resistance to sulfadoxine-pyrimethamine in Plasmodium falciparum and long unprotected intervals between intermittent treatment doses begs reconsideration of current preventative recommendations in pregnancy. Data remain limited on antimalarials during breastfeeding; while most first-line drugs appear safe, further research is needed.

Prospective Clinical Trial Assessing Species-Specific Efficacy of Artemether-Lumefantrine for the Treatment of Plasmodium malariae, Plasmodium ovale, and Mixed Plasmodium Malaria in Gabon

Treatment recommendations for Plasmodium malariae and Plasmodium ovale malaria are largely based on anecdotal evidence. The aim of this prospective study, conducted in Gabon, was to systematically assess the efficacy and safety of artemether-lumefantrine for the treatment of patients with uncomplicated P. malariae or P. ovale species monoinfections or mixed Plasmodium infections. Patients with microscopically confirmed P. malariae, P. ovale, or mixed-species malaria with at least one of these two Plasmodium species were treated with an oral, fixed-dose combination of artemether-lumefantrine for 3 consecutive days. The primary endpoints were per-protocol PCR-corrected adequate clinical and parasitological response (ACPR) on days 28 and 42. Tolerability and safety were recorded throughout the follow-up period. Seventy-two participants (42 male and 30 female) were enrolled; 62.5% of them had PCR-corrected mixed Plasmodium infections. Per protocol, PCR-corrected ACPR rates were 96.6% (95% confidence interval [CI], 91.9 to 100) on day 28 and 94.2% (95% CI, 87.7 to 100) on day 42. Considering Plasmodium species independently from their coinfecting species, day 42 ACPR rates were 95.5% (95% CI, 89.0 to 100) for P. falciparum, 100% (exact CI, 84.6 to 100) for P. malariae, 100% (exact CI, 76.8 to 100) for P. ovale curtisi, and 90.9% (95% CI, 70.7 to 100) for P. ovale wallikeri Study drug-related adverse events were generally mild or moderate. In conclusion, this clinical trial demonstrated satisfying antimalarial activity of artemether-lumefantrine against P. ovalewallikeri, P. ovale curtisi, P. malariae, and mixed Plasmodium infections, with per-protocol efficacies of 90% to 100% and without evident tolerability or safety concerns. (This trial was registered in the clinical study database ClinicalTrials.gov under the identifier NCT02528279.).

Treatment of uncomplicated and severe malaria during pregnancy

Over the past 10 years, the available evidence on the treatment of malaria during pregnancy has increased substantially. Owing to their relative ease of use, good sensitivity and specificity, histidine rich protein 2 based rapid diagnostic tests are appropriate for symptomatic pregnant women; however, such tests are less appropriate for systematic screening because they will not detect an important proportion of infections among asymptomatic women. The effect of pregnancy on the pharmacokinetics of antimalarial drugs varies greatly between studies and class of antimalarial drugs, emphasising the need for prospective studies in pregnant and non-pregnant women. For the treatment of malaria during the first trimester, international guidelines are being reviewed by WHO. For the second and third trimester of pregnancy, results from several trials have confirmed that artemisinin-based combination treatments are safe and efficacious, although tolerability and efficacy might vary by treatment. It is now essential to translate such evidence into policies and clinical practice that benefit pregnant women in countries where malaria is endemic. Access to parasitological diagnosis or appropriate antimalarial treatment remains low in many countries and regions. Therefore, there is a pressing need for research to identify quality improvement interventions targeting pregnant women and health providers. In addition, efficient and practical systems for pharmacovigilance are needed to further expand knowledge on the safety of antimalarial drugs, particularly in the first trimester of pregnancy.

In vitro investigation of clofazimine analogues for antiplasmodial, cytotoxic and pro-oxidative activities

BACKGROUND

Tetramethyl-piperidine-substituted, B4119 and B4158 have been shown to exhibit antiplasmodial activity.

OBJECTIVES

The in vitro antiplasmodial, cytotoxic and oxidative activities of clofazimine and its analogues, all TMP (tetramethylpiperidyl)-substituted phenazines except B669, were evaluated in this study.

METHODS

The antiplasmodial activity of the compounds against RB-1 and pfUP10 laboratory strains of Plasmodium falciparum was investigated by flow cytometry. The cytotoxic activity against HeLa cells and oxidative activity were studied employing colorimetric and cytochrome C reduction assays respectively.

RESULTS

The riminophenazine agents exhibited antiplasmodial action of varying degrees: B669, B4100 and B4103 showed the best activity while B4121 and B4169 exhibited significant activity at 2µg/ml. Clofazimine had no antiplasmodial activity. The compounds B4100, B4103, B4121 and B4169 exhibited significant cytotoxic activity against HeLa cells at concentrations of 0.5µg/ml and above while B669 was active at 2µg/ml. Clofazimine and B669 tested at a concentration of 0.5µg/ml caused enhancement (p ≤ 0.05) of neutrophil superoxide production when compared to the FMLP control while all the other TMP-derivatives had no effect (p ≥ 0.05).

CONCLUSION

Tetramethylpiperidyl-subsituted phenazines may potentially be useful antimalarial/antitumor agents with no pro-oxidative properties. In vivo studies on the agents relative to these properties are recommended.

Clinical and non-clinical safety of artemisinin derivatives in pregnancy

Malaria in pregnancy is a clinically wasting infectious disease, where drug therapy has to be promptly initiated. Currently, the treatment of this infection depends on the use of artemisinin derivatives. The World Health Organization does not recommend the use of these drugs in the first trimester of pregnancy due to non-clinical findings that have shown embryolethality and teratogenic effects. Nevertheless, until now, this toxicity has not been proved in humans. Artemisinin derivatives mechanisms of embryotoxicity are related to depletion of circulating embryonic primitive erythroblasts. Species differences in this sensitive period for toxicity and the presence of malaria infection, which could reduce drug distribution to the fetus, are significant to the risk assessment of artemisinin derivatives treatment to pregnant women. In this review we aimed to assess the results of non-clinical and clinical studies with artemisinin derivatives, their mechanisms of embryotoxicity and discuss the safety of their use during pregnancy.

Treatment regimens for pregnant women with falciparum malaria

INTRODUCTION

With increasing parasite drug resistance, the WHO has updated treatment recommendations for falciparum malaria including in pregnancy. This review assesses the evidence for choice of treatment for pregnant women.

AREAS COVERED

Relevant studies, primarily those published since 2010, were identified from reference databases and were used to identify secondary data sources. Expert commentary: WHO recommends use of intravenous artesunate for severe malaria, quinine-clindamycin for uncomplicated malaria in first trimester, and artemisinin combination therapy for uncomplicated malaria in second/third trimesters. Because fear of adverse outcomes has often excluded pregnant women from conventional drug development, available data for novel therapies are usually based on preclinical studies and cases of inadvertent exposure. Changes in antimalarial drug disposition in pregnancy have been observed but are yet to be translated into specific treatment recommendations. Such targeted regimens may become important as parasite resistance demands that drug exposure is optimized.

Treatment and prevention of malaria in pregnancy in the private health sector in Uganda: implications for patient safety

BACKGROUND

Malaria in pregnancy is a major public health problem in Uganda; and it is the leading cause of anaemia among pregnant women and low birth weight in infants. Previous studies have noted poor quality of care in the private sector. Thus there is need to explore ways of improving quality of care in the private sector that provides almost a half of health services in Uganda.

METHODS

A survey was conducted from August to October 2014 within 57 parishes in Mukono district, central Uganda. The selected parishes had a minimum of 200 households and at least one registered drug shop, pharmacy or private clinic. Data was collected using a structured questionnaire targeting one provider who was found on duty in each selected private health facility and consented to the study. The main variables were: provider characteristics, previous training received, type of drugs stocked, treatment and prevention practices for malaria among pregnant women. The main study outcome was the proportion of private health facilities who prescribe treatment of fever among pregnant women as recommended in the guidelines.

RESULTS

A total of 241 private health facilities were surveyed; 70.5 % were registered drug shops, 24.5 % private clinics and 5.0 % pharmacies. Treatment of fever among pregnant women in accordance with the national treatment guidelines was poor: 40.7 % in private clinics, decreasing to 28.2 % in drug shops and 16.7 % at pharmacies. Anti-malarial monotherapies sulphadoxine-pyrimethamine and quinine were commonly prescribed, often without consideration of gestational age. The majority of providers (>75 %) at all private facilities prescribed SP for intermittent preventive treatment but artemisinin-based combination therapy was prescribed: 8.3, 6.9 and 8.3 % respectively at drug shops, private clinics and pharmacies for prevention of malaria in pregnancy. Few facilities had malaria treatment guidelines; (44.1 % of private clinics, 17.9 % of drug shops, and 41.7 % at pharmacies. Knowledge of people at risk of malaria, P = 0.02 and availability of malaria treatment guidelines, P = 0.03 were the factors that most influenced correct treatment of fever in pregnancy.

CONCLUSION

Treatment of fever during pregnancy was poor in this study setting. These data highlight the need to develop interventions to improve patient safety and quality of care for pregnant women in the private health sector in Uganda.

Safety of artemisinins in first trimester of prospectively followed pregnancies: an observational study

BACKGROUND

Artemisinins, the most effective antimalarials available, are not recommended for falciparum malaria during the first trimester of pregnancy because of safety concerns. Therefore, quinine is used despite its poor effectiveness. Assessing artemisinin safety requires weighing the risks of malaria and its treatment. We aimed to assess the effect of first-trimester malaria and artemisinin treatment on miscarriage and major congenital malformations.

METHODS

In this observational study, we assessed data from antenatal clinics on the Thai-Myanmar border between Jan 1, 1994, and Dec 31, 2013. We included women who presented to antenatal clinics during their first trimester with a viable fetus. Women were screened for malaria, and data on malaria, antimalarial treatment, and birth outcomes were collected. The relationship between artemisinin treatments (artesunate, dihydroartemisinin, or artemether) and miscarriage or malformation was assessed using Cox regression with left-truncation and time-varying exposures.

FINDINGS

Of 55 636 pregnancies registered between 1994 and 2013, 25 485 pregnancies were analysed for first-trimester malaria and miscarriage, in which 2558 (10%) had first-trimester malaria. The hazard of miscarriage increased 1·61-fold after an initial first-trimester falciparum episode (95% CI 1·32-1·97; p<0·0001), 3·24-fold following falciparum recurrence (2·24-4·68; p<0·0001), and 2·44-fold (1·01-5·88; p=0·0473) following recurrent symptomatic vivax malaria. No difference was noted in miscarriage in first-line falciparum treatments with artemisinin (n=183) versus quinine (n=842; HR 0·78 [95% CI 0·45-1·34]; p=0·3645) or in risk of major congenital malformations (two [2%] of 109 [95% CI 0·22-6·47] versus eight (1%) of 641 [0·54-2·44], respectively).

INTERPRETATION

First-trimester falciparum and vivax malaria both increase the risk of miscarriage. We noted no evidence of an increased risk of miscarriage or of major congenital malformations associated with first-line treatment with an artemisinin derivative compared with quinine. In view of the low efficacy of quinine and wide availability of highly effective artemisinin-based combination therapies, it is time to reconsider first-trimester antimalarial treatment recommendations.

FUNDING

The Wellcome Trust and The Bill & Melinda Gates Foundation.

Imported malaria in pregnant women: A retrospective pooled analysis

BACKGROUND

Data on imported malaria in pregnant women are scarce.

METHOD

A retrospective, descriptive study of pooled data on imported malaria in pregnancy was done using data from 1991 to 2014 from 8 different collaborators in Europe, the United States and Japan. National malaria reference centres as well as specialists on this topic were asked to search their archives for cases of imported malaria in pregnancy. A total of 631 cases were collated, providing information on Plasmodium species, region of acquisition, nationality, country of residence, reason for travel, age, gestational age, prophylactic measures and treatment used, as well as on complications and outcomes in mother and child.

RESULTS

Datasets from some sources were incomplete. The predominant Plasmodium species was P. falciparum (78.5% of cases). Among the 542 cases where information on the use of chemoprophylaxis was known, 464 (85.6%) did not use chemoprophylaxis. The main reason for travelling was "visiting friends and relatives" VFR (57.8%) and overall, most cases of malaria were imported from West Africa (57.4%). Severe anaemia was the most frequent complication in the mother. Data on offspring outcome were limited, but spontaneous abortion was a frequently reported foetal outcome (n = 14). A total of 50 different variants of malaria treatment regimens were reported.

CONCLUSIONS

Imported cases of malaria in pregnancy are mainly P. falciparum acquired in sub-Saharan Africa. Malaria prevention and treatment in pregnant travellers is a challenge for travel medicine due to few data on medication safety and maternal and foetal outcomes. International, collaborative efforts are needed to capture standardized data on imported malaria cases in pregnant women.