Efficacy of artesunate-amodiaquine, dihydroartemisinin-piperaquine and artemether-lumefantrine for the treatment of uncomplicated Plasmodium falciparum malaria in Maradi, Niger

Therapeutic efficacy and tolerability of artemether-lumefantrine for uncomplicated Plasmodium falciparum malaria in Niger, 2020

BACKGROUND

Monitoring therapeutic efficacy is important to ensure the efficacy of artemisinin-based combination therapy (ACT) for malaria. The current first-line treatment for uncomplicated malaria recommended by the National Malaria Control Program in Niger is artemether-lumefantrine (AL). In 2020, an in vivo study was carried out to evaluate clinical and parasitological responses to AL as well as the molecular resistance to the drug in three sentinel sites: Agadez, Tessaoua and Gaya, in Niger.

METHODS

A multi-center, single-arm trial was conducted according to the 28-day World Health Organization (WHO) 2009 therapeutic efficacy study protocol. Children between 6 months and 15 years with confirmed uncomplicated Plasmodium falciparum infection and 1000-200,000 asexual parasites/μL of blood were enrolled and followed up for 28 days. Uncorrected and PCR-corrected efficacy results at day 28 were calculated, and molecular correction was performed by genotyping the msp1, msp2, and glurp genes. The pfk13, pfdhfr, pfdhps, pfcrt and pfmdr genes were analyzed by PCR and Sanger sequencing. The Kaplan-Meier curve assessed parasite clearance.

RESULTS

A total of 255 patients were enrolled in the study. The adequate clinical and parasitological response after PCR correction was 98.9% (95% CI 96.4-101.0%), 92.2% (85.0-98.5%) and 97.1% (93.1-101.0%) in Gaya, Tessaoua and Agadez, respectively. No adverse events were observed. Ten mutations (SNP) were found, including 7 synonyms (K248K, G690G, E691E, E612E, C469C, G496G, P718P) and 3 non-synonyms (N594K, R255K, V714S). Two mutations emerged: N594K and V714S. The R255K mutation detected in Southeast Asia was also detected. The pfdhpsK540E and pfdhfrI164L mutations associated with high levels of resistance are absent. There is a reversal of chloroquine resistance.

CONCLUSION

The study findings indicate that AL is effective and well tolerated for the treatment of uncomplicated malaria in three sites in Niger. The emergence of a pfk13 mutation requires additional testing such as the Ring Stage Assay and CRISPR/Cas9 to confirm the role of these emerging mutations. Trial registration NCT05070520, October 7, 2021.

Therapeutic efficacy of artesunate-amodiaquine and artemether-lumefantrine for the treatment of uncomplicated falciparum malaria in Chad: clinical and genetic surveillance

BACKGROUND

Artesunate-amodiaquine (AS-AQ) and artemether-lumefantrine (AL) are the currently recommended first-and second-line therapies for uncomplicated Plasmodium falciparum infections in Chad. This study assessed the efficacy of these artemisinin-based combinations, proportion of day 3 positive patients, proportions of molecular markers associated with P. falciparum resistance to anti-malarial drugs and variable performance of HRP2-based malaria rapid diagnostic tests (RDTs).

METHODS

A single-arm prospective study assessing the efficacy of AS-AQ and AL at three sites (Doba, Kelo and Koyom) was conducted between November 2020 to January 2021. Febrile children aged 6 to 59 months with confirmed uncomplicated P. falciparum infection were enrolled sequentially first to AS-AQ and then AL at each site and followed up for 28 days. The primary endpoint was PCR-adjusted adequate clinical and parasitological response (ACPR). Samples collected on day 0 were analysed for mutations in pfkelch13, pfcrt, pfmdr-1, pfdhfr, pfdhps genes and deletions in pfhrp2/pfhrp3 genes.

RESULTS

By the end of 28-day follow-up, per-protocol PCR corrected ACPR of 97.8% (CI 95% 88.2-100) in Kelo and 100% in Doba and Kayoma were observed among AL treated patients. For ASAQ, 100% ACPR was found in all sites. All, but one patient, did not have parasites detected on day 3. Out of the 215 day 0 samples, 96.7% showed pfkelch13 wild type allele. Seven isolates carried nonsynonymous mutations not known to be associated artemisinin partial resistance (ART-R). Most of samples had a pfcrt wild type allele (79% to 89%). The most prevalent pfmdr-1 allele detected was the single mutant 184F (51.2%). For pfdhfr and pfdhps mutations, the quintuple mutant allele N51I/C59R/S108N + G437A/540E responsible for SP treatment failures in adults and children was not detected. Single deletion in the pfhrp2 and pfhrp3 gene were detected in 10/215 (4.7%) and 2/215 (0.9%), respectively. Dual pfhrp2/pfhrp3 deletions, potentially threatening the efficacy of HRP2-based RDTs, were observed in 5/215 (2.3%) isolates.

CONCLUSION

The results of this study confirm that AS-AQ and AL treatments are highly efficacious in study areas in Chad. The absence of known pfkelch13 mutations in the study sites and the high parasite clearance rate at day 3 suggest the absence of ART-R. The absence of pfdhfr/pfdhps quintuple or sextuple (quintuple + 581G) mutant supports the continued use of SP for IPTp during pregnancy. The presence of parasites with dual pfhrp2/pfhrp3 deletions, potentially threatening the efficacy of HRP2-based RDTs, warrants the continued surveillance. Trial registration ACTRN12622001476729.

Stakeholder perceptions on the deployment of multiple first-line therapies for uncomplicated malaria: a qualitative study in the health district of Kaya, Burkina Faso

Background

In Burkina Faso, malaria remains the first cause of medical consultation and hospitalization in health centres. First-line case management of malaria in the country’s health facilities is based on the use of artemisinin-based combination therapy (ACT). To optimize the use of these anti-malarial drugs in the perspective of mitigating the emergence of artemisinin resistance, which is a serious threat to malaria control and elimination, a pilot programme using multiple first-line therapies (MFTs) [three artemisinin-based combinations—pyronaridine–artesunate, dihydroartemisinin–piperaquine and artemether-lumefantrine] has been designed for implementation. As the success of this MFT pilot programme depends on the perceptions of key stakeholders in the health system and community members, the study aimed to assess their perceptions on the implementation of this strategy.

Methods

Semi-structured interviews, including 27 individual in-depth interviews and 41 focus groups discussions, were conducted with key stakeholders including malaria control policymakers and implementers, health system managers, health workers and community members. Volunteers from targets stakeholder groups were randomly selected. All interviews were recorded, transcribed and translated. Content analysis was performed using the qualitative software programme QDA Miner.

Results

The interviews revealed a positive perception of stakeholders on the implementation of the planned MFT programme. They saw the strategy as an opportunity to strengthen the supply of anti-malarial drugs and improve the management of fever and malaria. However, due to lack of experience with the products, health workers and care givers expressed some reservations about the effectiveness and side-effect profiles of the two anti-malarial drugs included as first-line therapy in the MFT programme (pyronaridine–artesunate, dihydroartemisinin–piperaquine). Questions were raised about the appropriateness of segmenting the population into three groups and assigning a specific drug to each group.

Conclusion

The adherence of both populations and key stakeholders to the MFT implementation strategy will likely depend on the efficacy of the proposed drugs, the absence of, or low frequency of, side-effects, the cost of drugs and availability of the different combinations.

Artesunate-amodiaquine and artemether-lumefantrine for the treatment of uncomplicated falciparum malaria in Liberia: in vivo efficacy and frequency of molecular markers

Background

Artesunate–amodiaquine (ASAQ) and Artemether–lumefantrine (AL) are the recommended treatment for uncomplicated Plasmodium falciparum malaria in Liberia. Intermittent preventive treatment with sulfadoxine/pyrimethamine is also recommended for pregnant women. The therapeutic efficacy of Artesunate–amodiaquine and Artemether–lumefantrine, and the frequency of molecular markers associated with anti-malarial drug resistance were investigated.

Methods

The therapeutic efficacy of ASAQ and AL was evaluated using the standard World Health Organization protocol (WHO. Methods for Surveillance of Antimalarial Drug Efficacy. Geneva: World Health Organization; 2009. https://www.who.int/malaria/publications/atoz/9789241597531/en/). Eligible children were recruited and monitored clinically and parasitologically for 28 days. Polymorphisms in the Pfkelch 13, chloroquine resistance transporter (Pfcrt), multidrug resistance 1 (Pfmdr-1), dihydrofolate reductase (Pfdhfr), and dihydropteroate synthase (Pfdhps) genes and copy number variations in the plasmepsin-2 (Pfpm2) gene were assessed in pretreatment samples.

Results

Of the 359 children enrolled, 180 were treated with ASAQ (89 in Saclepea and 91 in Bensonville) and 179 with AL (90 in Sinje and 89 in Kakata). Of the recruited children, 332 (92.5%) reached study endpoints. PCR-corrected per-protocol analysis showed ACPR of 90.2% (95% CI: 78.6–96.7%) in Bensonville and 92.7% (95% CI: 83.4.8–96.5%) in Saclepea for ASAQ, while ACPR of 100% was observed in Kakata and Sinje for AL. In both treatment groups, only two patients had parasites on day 3. No artemisinin resistance associated Pfkelch13 mutations or multiple copies of Pfpm2 were found. Most samples tested had the Pfcrt 76 T mutation (80/91, 87.9%), while the Pfmdr-1 86Y (40/91, 44%) and 184F (47/91, 51.6%) mutations were less frequent. The Pfdhfr triple mutant (51I/59R/108 N) was the predominant allele (49.2%). For the Pfdhps gene, it was the 540E mutant (16.0%), and the 436A mutant (14.3%). The quintuple allele (51I/59R/108 N-437G/540E) was detected in only one isolate (1/357).

Conclusion

This study reports a decline in the efficacy of ASAQ treatment, while AL remained highly effective, supporting the recent decision by NMCP to replace ASAQ with AL as first-line treatment for uncomplicated falciparum malaria. No association between the presence of the mutations in Pfcrt and Pfmdr-1 and the risk of parasite recrudescence in patients treated with ASAQ was observed. Parasites with signatures known to be associated with artemisinin and piperaquine resistance were not detected. The very low frequency of the quintuple Pfdhfr/Pfdhps mutant haplotype supports the continued use of SP for IPTp. Monitoring of efficacy and resistance markers of routinely used anti-malarials is necessary to inform malaria treatment policy.

Trial registration ACTRN12617001064392.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-022-04140-7.

Therapeutic efficacy of artemether-lumefantrine, artesunate-amodiaquine and dihydroartemisinin-piperaquine in the treatment of uncomplicated Plasmodium falciparum malaria in Sub-Saharan Africa: A systematic review and meta-analysis

Background

Sub-Saharan Africa has the highest burden of malaria in the world. Artemisinin-based combination therapies (ACTs) have been the cornerstone in the efforts to reduce the global burden of malaria. In the effort to facilitate early detection of resistance for artemisinin derivatives and partner drugs, WHO recommends monitoring of ACT’s efficacy in the malaria endemic countries. The present systematic meta-analysis study summarises the evidence of therapeutic efficacy of the commonly used artemisinin-based combinations for the treatment of uncomplicated P. falciparum malaria in Sub-Saharan Africa after more than a decade since the introduction of the drugs.

Methods

Fifty two studies carried out from 2010 to 2020 on the efficacy of artemether-lumefantrine or dihydro-artemisinin piperaquine or artesunate amodiaquine in patients with uncomplicated P. falciparum malaria in Sub-Saharan Africa were searched for using the Google Scholar, Cochrane Central Register of controlled trials (CENTRAL), PubMed, Medline, LILACS, and EMBASE online data bases. Data was extracted by two independent reviewers. Random analysis effect was performed in STATA 13. Heterogeneity was established using I² statistics.

Results

Based on per protocol analysis, unadjusted cure rates in malaria infected patients treated with artemether-lumefantrine (ALU), artesunate-amodiaquine (ASAQ) and dihydroartemisinin-piperaquine (DHP) were 89%, 94% and 91% respectively. However, the cure rates after PCR correction were 98% for ALU, 99% for ASAQ and 99% for DHP.

Conclusion

The present meta-analysis reports the overall high malaria treatment success for artemether-lumefantrine, artesunate-amodiaquine and dihydroartemisinin-piperaquine above the WHO threshold value in Sub-Saharan Africa.

Safety of dihydroartemisinin-piperaquine versus artemether-lumefantrine for the treatment of uncomplicated Plasmodium falciparum malaria among children in Africa: a systematic review and meta-analysis of randomized control trials

BACKGROUND

The efficacies of artemisinin based combinations have been excellent in Africa, but also comprehensive evidence regarding their safety would be important. The aim of this review was to synthesize available evidence on the safety of dihydroartemisinin-piperaquine (DHA-PQ) compared to artemether-lumefantrine (AL) for the treatment of uncomplicated Plasmodium falciparum malaria among children in Africa.

METHODS

A systematic literature search was done to identify relevant articles from online databases PubMed/ MEDLINE, Embase, and Cochrane Center for Clinical Trial database (CENTRAL) for retrieving randomized control trials comparing safety of DHA-PQ and AL for treatment of uncomplicated P. falciparum malaria among children in Africa. The search was performed from August 2020 to 30 April 2021. Using Rev-Man software (V5.4.1), the extracted data from eligible studies were pooled as risk ratio (RR) with 95% confidence interval (CI).

RESULTS

In this review, 18 studies were included, which involved 10,498 participants were included. Compared to AL, DHA-PQ was associated with a slightly higher frequency of early vomiting (RR 2.26, 95% CI 1.46 to 3.50; participants = 7796; studies = 10; I2 = 0%, high quality of evidence), cough (RR 1.06, 95% CI 1.01 to 1.11; participants = 8013; studies = 13; I2 = 0%, high quality of evidence), and diarrhoea (RR 1.16, 95% CI 1.03 to 1.31; participants = 6841; studies = 11; I2 = 8%, high quality of evidence) were more frequent in DHA-PQ treatment arm.

CONCLUSION

From this review, it can be concluded that early vomiting, diarrhoea, and cough were common were significantly more frequent in patients who were treated with the DHA-PQ than that of AL, and both drugs are well tolerated. More studies comparing AL with DHA-PQ are needed to determine the comparative safety of these drugs.

Efficacy and safety of artemether-lumefantrine and dihydroartemisinin-piperaquine for the treatment of uncomplicated Plasmodium falciparum malaria and prevalence of molecular markers associated with artemisinin and partner drug resistance in Uganda

Background

In Uganda, artemether-lumefantrine (AL) is first-line therapy and dihydroartemisinin-piperaquine (DP) second-line therapy for the treatment of uncomplicated malaria. This study evaluated the efficacy and safety of AL and DP in the management of uncomplicated falciparum malaria and measured the prevalence of molecular markers of resistance in three sentinel sites in Uganda from 2018 to 2019.

Methods

This was a randomized, open-label, phase IV clinical trial. Children aged 6 months to 10 years with uncomplicated falciparum malaria were randomly assigned to treatment with AL or DP and followed for 28 and 42 days, respectively. Genotyping was used to distinguish recrudescence from new infection, and a Bayesian algorithm was used to assign each treatment failure a posterior probability of recrudescence. For monitoring resistance, Pfk13 and Pfmdr1 genes were Sanger sequenced and plasmepsin-2 copy number was assessed by qPCR.

Results

There were no early treatment failures. The uncorrected 28-day cumulative efficacy of AL ranged from 41.2 to 71.2% and the PCR-corrected cumulative 28-day efficacy of AL ranged from 87.2 to 94.4%. The uncorrected 28-day cumulative efficacy of DP ranged from 95.8 to 97.9% and the PCR-corrected cumulative 28-day efficacy of DP ranged from 98.9 to 100%. The uncorrected 42-day efficacy of DP ranged from 73.5 to 87.4% and the PCR-corrected 42-day efficacy of DP ranged from 92.1 to 97.5%. There were no reported serious adverse events associated with any of the regimens. No resistance-associated mutations in the Pfk13 gene were found in the successfully sequenced samples. In the AL arm, the NFD haplotype (N86Y, Y184F, D1246Y) was the predominant Pfmdr1 haplotype, present in 78 of 127 (61%) and 76 of 110 (69%) of the day 0 and day of failure samples, respectively. All the day 0 samples in the DP arm had one copy of the plasmepsin-2 gene.

Conclusions

DP remains highly effective and safe for the treatment of uncomplicated malaria in Uganda. Recurrent infections with AL were common. In Busia and Arua, the 95% confidence interval for PCR-corrected AL efficacy fell below 90%. Further efficacy monitoring for AL, including pharmacokinetic studies, is recommended.

Trial registration The trail was also registered with the ISRCTN registry with study Trial No. PACTR201811640750761

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-021-04021-5.

Comparative effect of dihydroartemisinin-piperaquine and artemether-lumefantrine on gametocyte clearance and haemoglobin recovery in children with uncomplicated Plasmodium falciparum malaria in Africa: a systematic review and meta-analysis of randomized control trials

BACKGROUND

Plasmodium falciparum gametocytaemia has been associated with anaemia. The aim of this review was to synthesize available evidence on the comparative effect of dihydroartemisinin-piperaquine (DHA-PQ) and artemether-lumefantrine (AL) on gametocyte clearance and haemoglobin recovery in children with uncomplicated P. falciparum malaria in Africa.

METHODS

A systematic literature search was undertaken to identify relevant articles from online databases. The search was performed from August 2020 to 30 April 2021. Extracted data from eligible studies were pooled as risk ratios with 95% confidence intervals (CI).

RESULTS

Gametocyte carriage was reduced in both treatment groups, with no significant difference found between the groups. However, on days 28 and 42, a significant increase in serum haemoglobin level from baseline was observed in the DHA-PQ group (standardized mean difference 0.15, 95% CI 0.05-0.26; participants=2715; studies=4; I²⁼32%, high quality of evidence) compared with the AL group (mean difference 0.35, 95% CI 0.12-0.59; participants=1434; studies=3; I²=35%, high quality of evidence).

CONCLUSION

DHA-PQ had a greater impact on haemoglobin recovery than AL on days 28 and 42; this difference was significant.

Therapeutic efficacy of artesunate-amodiaquine and artemether-lumefantrine and polymorphism in Plasmodium falciparum kelch13-propeller gene in Equatorial Guinea

Background

Artesunate-amodiaquine (ASAQ) and artemether-lumefantrine (AL) are the currently recommended first- and second-line therapies for uncomplicated Plasmodium falciparum infections in Equatorial Guinea. This study was designed to evaluate the efficacy of these artemisinin-based combinations and detect mutations in P. falciparum kelch13-propeller domain gene (Pfkelch13).

Methods

A single-arm prospective study evaluating the efficacy of ASAQ and AL at three sites: Malabo, Bata and Ebebiyin was conducted between August 2017 and July 2018. Febrile children aged six months to 10 years with confirmed uncomplicated P. falciparum infection and other inclusion criteria were sequentially enrolled first in ASAQ and then in AL at each site, and followed up for 28 days. Clinical and parasitological parameters were assessed. The primary endpoint was PCR-adjusted adequate clinical and parasitological response (ACPR). Samples on day-0 were analysed for mutations in Pfkelch13 gene.

Results

A total 264 and 226 patients were enrolled in the ASAQ and AL treatment groups, respectively. Based on per-protocol analysis, PCR-adjusted cure rates of 98.6% to 100% and 92.4% to 100% were observed in patients treated with ASAQ and AL, respectively. All study children in both treatment groups were free of parasitaemia by day-3. Of the 476 samples with interpretable results, only three samples carried non-synonymous Pfkelch13 mutations (E433D and A578S), and none of them is the known markers associated with artemisinin resistance.

Conclusion

The study confirmed high efficacy of ASAQ and AL for the treatment of uncomplicated falciparum infections as well as the absence of delayed parasite clearance and Pfkelch13 mutations associated with artemisinin resistance. Continued monitoring of the efficacy of these artemisinin-based combinations, at least every two years, along with molecular markers associated with artemisinin and partner drug resistance is imperative to inform national malaria treatment policy and detect resistant parasites early.

Trial registration ACTRN12617000456358, Registered 28 March 2017; http://www.anzctr.org.au/trial/MyTrial.aspx

Methodological approaches for analysing data from therapeutic efficacy studies

Several anti-malarial drugs have been evaluated in randomized clinical trials to treat acute uncomplicated Plasmodium falciparum malaria. The outcome of anti-malarial drug efficacy studies is classified into one of four possible outcomes defined by the World Health Organization: adequate clinical and parasitological response, late parasitological failure, late clinical failure, early treatment failure. These four ordered categories are ordinal data, which are reduced to either a binary outcome (i.e., treatment success and treatment failure) to calculate the proportions of treatment failure or to time-to-event outcome for KaplanMeier survival analysis. The arbitrary transition from 4-level ordered categories to 2-level type categories results in a loss of statistical power. In the opinion of the authors, this outcome can be considered as ordinal at a fixed endpoint or at longitudinal endpoints. Alternative statistical methods can be applied to 4-level ordinal categories of therapeutic response to optimize data exploitation. Furthermore, network meta-analysis is useful not only for direct comparison of drugs which were evaluated together in a randomized design, but also for indirect comparison of different artemisinin-based combinations across different clinical studies using a common drug comparator, with the aim to determine the ranking order of drug efficacy. Previous works conducted in Cameroonian children served as data source to illustrate the feasibility of these novel statistical approaches. Data analysis based on ordinal end-point may be helpful to gain further insight into anti-malarial drug efficacy.

Efficacy and safety of dihydroartemisinin-piperaquine versus artemether-lumefantrine for treatment of uncomplicated Plasmodium falciparum malaria in Ugandan children: a systematic review and meta-analysis of randomized control trials

Background

The emergence of artemisinin resistance in Southeast Asia and Plasmodium falciparum kelch13 propeller gene mutations in sub-Saharan African pose the greatest threat to global efforts to control malaria. This is a critical concern in Uganda, where artemisinin-based combination therapy (ACT) is the first-line treatment for uncomplicated falciparum. The objective of this study was to compare the efficacy and safety of dihydroartemisinin–piperaquine (DHA–PQ) and artemether–lumefantrine (AL) for the treatment of uncomplicated falciparum malaria in Ugandan children.

Methods

A search of PubMed and the Cochrane Central Register of Controlled Trials for retrieving randomized controlled trials comparing the efficacy and safety of DHA–PQ and AL for treatment of uncomplicated falciparum malaria in Ugandan children was done. The search was performed up to 31 August 2020. The data extracted from eligible studies and pooled as risk ratio (RR) with a 95% confidence interval (CI), using Rev Man Software (5.4). The protocol was registered in PROSPERO, ID: CRD42020182354.

Results

Eleven trials were included in this review and two of them only included under safety outcome. Total 3798 participants were enrolled. The PCR unadjusted treatment failure was significantly lower with DHA–PQ at day 28 (RR 0.30, 95% CI 0.19–0.49; participants = 7863; studies = 5; I² = 93%, low quality evidence) and at day 42 (RR 0.53, 95% CI 0.38–0.76; participants = 1618; studies = 4; I² = 79%, moderate quality of evidence). The PCR adjusted treatment failure at day 42 was significantly lower with DHA–PQ treatment group (RR 0.45, 95% CI 0.28 to 0.72; participants = 1370; studies = 5, high quality of evidence), and it was below 5% in both arms at day 28 (moderate quality of evidence). AL showed a longer prophylactic effect on new infections which may last for up to 63 days (PCR-adjusted treatment failure: RR 2.04, 95% CI 1.13–3.70; participants = 1311; studies = 2, moderate quality of evidence). Compared to AL, DHA–PQ was associated with a slightly higher frequency of cough (RR 1.07, 95% CI 1.01 to 1.13; 2575 participants; six studies; high quality of evidence). In both treatment groups, the risk of recurrent parasitaemia due to possible recrudescence was less than 5% at day 28. The appearance of gametocyte between 29 and 42 days was also significantly lower in DHA–PQ than AL (RR 0.26, 95% CI 0.12 to 0.56; participants = 623; studies = 2; I² = 0%).

Conclusion

Compared to AL, DHA–PQ appeared to reduce treatment failure and gametocyte carriage in Ugandan children. This may trigger DHA–PQ to become the first-line treatment option. Both treatments were safe and well-tolerated.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-021-03711-4.

Therapeutic Efficacy of Artemether-Lumefantrine (Coartem®) for the Treatment of Uncomplicated Falciparum Malaria in Africa: A Systematic Review

Background

Africa still bears the largest burden of malaria as the majority of infections in the continent are caused by P. falciparum. Artemether-lumefantrine (AL, Coartem®) is the most widely used artemisinin-based combination therapy (ACT), for treating uncomplicated falciparum malaria globally. However, the development of resistance to antimalarial drugs is a major challenge for malaria control. In this review, the efficacy of AL for the treatment of uncomplicated falciparum malaria in Africa was evaluated.

Methods

Articles published between January 2015 and July 2019 were systematically searched using comprehensive search strings from PubMed/Medline, SCOPUS, and grey literature from Google Scholar. Interventional studies that followed patients for at least 28 days were included. Two reviewers independently assessed study eligibility, extracted data, and assessed risk of bias. All the included articles were measured to be good quality. While computing the efficacy of AL, polymerase chain reaction (PCR)–corrected cure rate (adequate clinical and parasitological response, ACPR) at day 28 was considered as the main endpoint. Meta-analysis was computed using STATA v 15 to calculate the pooled ACPR.

Results

In this review, 39 articles that reported the treatment outcome of 8,320 patients were included. After 28 days of follow-up, the pooled PCR uncorrected and corrected APCR was at 87% (95% CI: 85-90%) and 97.0% (95% CI: 96-98%), respectively. Moreover, the proportion of early treatment failure (ETF) was almost 0%, while most of the included articles reported <8% late treatment failures. The reinfection and recrudescence rate was less than 10% and 2.6%, respectively, within 28 days. We noted rapid fever and parasite clearance in which greater than 93% and 94% patients were parasite and fever free at day three following AL treatment.

Conclusions

This review discovered that despite more than a decade since its introduction, Coartem® remains effective and thus could continue to be the drug of choice for the treatment of uncomplicated falciparum malaria for all age groups in Africa. However, the risk of new emerging resistance for this combination warrants regular monitoring of its efficacy across the continent.

Therapeutic Efficacy of Artemether-Lumefantrine for Uncomplicated Falciparum Malaria in Northern Zambia

Artemether-lumefantrine (AL) is a first-line agent for uncomplicated malaria caused by Plasmodium falciparum. The WHO recommends periodic therapeutic efficacy studies of antimalarial drugs for the detection of malaria parasite drug resistance and to inform national malaria treatment policies. We conducted a therapeutic efficacy study of AL in a high malaria transmission region of northern Zambia from December 2014 to July 2015. One hundred children of ages 6 to 59 months presenting to a rural health clinic with uncomplicated falciparum malaria were admitted for treatment with AL (standard 6-dose regimen) and followed weekly for 5 weeks. Parasite counts were taken every 6 hours during treatment to assess parasite clearance. Recurrent episodes during follow-up (n = 14) were genotyped to distinguish recrudescence from reinfection and to identify drug resistance single nucleotide polymorphisms (SNPs) and multidrug resistance protein 1 (mdr1) copy number variation. Day 7 lumefantrine concentrations were measured for correspondence with posttreatment reinfection. All children who completed the parasite clearance portion of the study (n = 94) were microscopy-negative by 72 hours. The median parasite elimination half-life was 2.7 hours (interquartile range: 2.1-3.3). Genotype-corrected therapeutic efficacy was 98.8% (95% CI: 97.6-100). Purported artemisinin and lumefantrine drug resistance SNPs in atp6, 3D7_1451200, and mdr1 were detected but did not correlate with parasite recurrence, nor did day 7 lumefantrine concentrations. In summary, AL was highly effective for the treatment of uncomplicated falciparum malaria in northern Zambia during the study period. The high incidence of recurrent parasitemia was consistent with reinfection due to high, perennial malaria transmission.

In vivo/ex vivo efficacy of artemether-lumefantrine and artesunate-amodiaquine as first-line treatment for uncomplicated falciparum malaria in children: an open label randomized controlled trial in Burkina Faso

BACKGROUND

Artemisinin-based combination therapy (ACT) is recommended to improve malaria treatment efficacy and limit drug-resistant parasites selection in malaria endemic areas. 5 years after they were adopted, the efficacy and safety of artemether-lumefantrine (AL) and artesunate-amodiaquine (ASAQ), the first-line treatments for uncomplicated malaria were assessed in Burkina Faso.

METHODS

In total, 440 children with uncomplicated Plasmodium falciparum malaria were randomized to receive either AL or ASAQ for 3 days and were followed up weekly for 42 days. Blood samples were collected to investigate the ex vivo susceptibility of P. falciparum isolates to lumefantrine, dihydroartemisinin (the active metabolite of artemisinin derivatives) and monodesethylamodiaquine (the active metabolite of amodiaquine). The modified isotopic micro test technique was used to determine the 50% inhibitory concentration (IC50) values. Primary endpoints were the risks of treatment failure at days 42.

RESULTS

Out of the 440 patients enrolled, 420 (95.5%) completed the 42 days follow up. The results showed a significantly higher PCR unadjusted cure rate in ASAQ arm (71.0%) than that in the AL arm (49.8%) on day 42, and this trend was similar after correction by PCR, with ASAQ performing better (98.1%) than AL (91.1%). Overall adverse events incidence was low and not significantly different between the two treatment arms. Ex vivo results showed that 6.4% P. falciparum isolates were resistant to monodesthylamodiaquine. The coupled in vivo/ex vivo analysis showed increased IC50 values for lumefantrine and monodesethylamodiaquine at day of recurrent parasitaemia compared to baseline values while for artesunate, IC50 values remained stable at baseline and after treatment failure (p > 0.05).

CONCLUSION

These findings provide substantial evidence that AL and ASAQ are highly efficacious for the treatment of uncomplicated malaria in children in Burkina Faso. However, the result of P. falciparum susceptibility to the partner drugs advocates the need to regularly replicate such surveillance studies. This would be particularly indicated when amodiaquine is associated in seasonal malaria chemoprophylaxis (SMC) mass drug administration in children under 5 years in Burkina Faso. Trial registration clinicaltrials, NCT00808951. Registered 05 December 2008,https://clinicaltrials.gov/ct2/show/NCT00808951?cond=NCT00808951&rank=1.

Monitoring of efficacy, tolerability and safety of artemether-lumefantrine and artesunate-amodiaquine for the treatment of uncomplicated Plasmodium falciparum malaria in Lambaréné, Gabon: an open-label clinical trial

Background

Malaria remains a major public health problem, affecting mainly low-and middle-income countries. The management of this parasitic disease is challenged by ever increasing drug resistance. This study, investigated the therapeutic efficacy, tolerability and safety of artemether–lumefantrine (AL) and artesunate–amodiaquine (AS–AQ), used as first-line drugs to treat uncomplicated malaria in Lambaréné, Gabon.

Methods

A non-randomized clinical trial was conducted between October 2017 and March 2018 to assess safety, clinical and parasitological efficacy of fixed-doses of AL and AS–AQ administered to treat uncomplicated Plasmodium falciparum malaria in children aged from 6 months to 12 years. After 50 children were treated with AL, another 50 children received ASAQ. The 2009 World Health Organization protocol for monitoring of the efficacy of anti‑malarial drugs was followed. Molecular markers msp1 and msp2 were used to differentiate recrudescence and reinfection. For the investigation of artemisinin resistant markers, gene mutations in Pfk13 were screened.

Results

Per-protocol analysis on day 28 showed a PCR corrected cure rate of 97% (95% CI 86–100) and 95% (95% CI 84–99) for AL and AS–AQ, respectively. The most frequent adverse event in both groups was asthenia. No mutations in the kelch-13 gene associated with artemisinin resistance were identified. All participants had completed microscopic parasite clearance by day 3 post-treatment.

Conclusion

This study showed that AL and AS–AQ remain efficacious, well-tolerated, and are safe to treat uncomplicated malaria in children from Lambaréné. However, a regular monitoring of efficacy and a study of molecular markers of drug resistance to artemisinin in field isolates is essential.

Trial registration ANZCTR, ACTRN12616001600437. Registered 18 November, http://www.anzctr.org.au/TrialSearch.aspx?searchTxt=ACTRN12616001600437p&isBasic=True

Are k13 and plasmepsin II genes, involved in Plasmodium falciparum resistance to artemisinin derivatives and piperaquine in Southeast Asia, reliable to monitor resistance surveillance in Africa?

Mutations in the propeller domain of Plasmodium falciparum kelch 13 (Pfk13) gene are associated with artemisinin resistance in Southeast Asia. Artemisinin resistance is defined by increased ring survival rate and delayed parasite clearance half-life in patients. Additionally, an amplification of the Plasmodium falciparum plasmepsin II gene (pfpm2), encoding a protease involved in hemoglobin degradation, has been found to be associated with reduced in vitro susceptibility to piperaquine in Cambodian P. falciparum parasites and with dihydroartemisinin–piperaquine failures in Cambodia. The World Health Organization (WHO) has recommended the use of these two genes to track the emergence and the spread of the resistance to dihydroartemisinin–piperaquine in malaria endemic areas. Although the resistance to dihydroartemisinin–piperaquine has not yet emerged in Africa, few reports on clinical failures suggest that k13 and pfpm2 would not be the only genes involved in artemisinin and piperaquine resistance. It is imperative to identify molecular markers or drug resistance genes that associate with artemisinin and piperaquine in Africa. K13 polymorphisms and Pfpm2 copy number variation analysis may not be sufficient for monitoring the emergence of dihydroartemisinin–piperaquine resistance in Africa. But, these markers should not be ruled out for tracking the emergence of resistance.

Efficacy and safety of dihydroartemisinin-piperaquine for treatment of Plasmodium falciparum uncomplicated malaria in adult patients on antiretroviral therapy in Malawi and Mozambique: an open label non-randomized interventional trial

BACKGROUND

HIV-infected individuals on antiretroviral therapy (ART) require treatment with artemisinin-based combination therapy (ACT) when infected with malaria. Dihydroartemisinin-piperaquine (DPQ) is recommended for treatment of Plasmodium falciparum malaria, but its efficacy and safety has not been evaluated in HIV-infected individuals on ART, among whom drug-drug interactions are expected. Day-42 adequate clinical and parasitological response (ACPR) and incidence of adverse events were assessed in HIV-infected individuals on non-nucleoside reverse transcriptase inhibitor-based ART (efavirenz and nevirapine) with uncomplicated P. falciparum malaria treated with dihydroartemisinin-piperaquine.

METHODS

An open label single arm clinical trial was conducted in Malawi (Blantyre and Chikhwawa districts) and Mozambique (Manhiça district) involving patients aged 15-65 years with uncomplicated P. falciparum malaria who were on efavirenz-based or nevirapine-based ART. They received a directly-observed 3-day standard treatment of DPQ and were followed up until day 63 for malaria infection and adverse events. Day-42 PCR-corrected-ACPRs (95% confidence interval [CI]) were calculated for the intention-to-treat (ITT) population.

RESULTS

The study enrolled 160 and 61 patients on efavirenz and nevirapine-based ART, with a baseline geometric mean (95% CI) parasite density of 2681 (1964-3661) and 9819 (6606-14,593) parasites/µL, respectively. The day-42 PCR-corrected ACPR (95% CI) was 99.4% (95.6-99.9%) in the efavirenz group and 100% in the nevirapine group. Serious adverse events occurred in 5.0% (8/160) and 3.3% (2/61) of the participants in the efavirenz and nevirapine group, respectively, but none were definitively attributable to DPQ. Cases of prolonged QT interval (> 60 ms from baseline) occurred in 31.2% (48/154) and 13.3% (8/60) of the patients on the efavirenz and nevirapine ART groups, respectively. These were not clinically significant and resolved spontaneously over time. As this study was not designed to compare the efficacy and safety of DPQ in the two ART groups, no formal statistical comparisons were made between the two ART groups.

CONCLUSIONS

DPQ was highly efficacious and safe for the treatment of malaria in HIV-infected patients concurrently taking efavirenz- or nevirapine-based ART, despite known pharmacokinetic interactions between dihydroartemisinin-piperaquine and efavirenz- or nevirapine-based ART regimens. Trial registration Pan African Clinical Trials Registry (PACTR): PACTR201311000659400. Registered on 4 October 2013, https://pactr.samrc.ac.za/Search.aspx.

Efficacy and safety of artemether-lumefantrine as treatment for Plasmodium falciparum uncomplicated malaria in adult patients on efavirenz-based antiretroviral therapy in Zambia: an open label non-randomized interventional trial

BACKGROUND

HIV-infected individuals on antiretroviral therapy (ART) require treatment with artemisinin-based combination therapy (ACT) when infected with malaria. Artemether-lumefantrine (AL) is the most commonly used ACT for treatment of falciparum malaria in Africa but there is limited evidence on the safety and efficacy of AL in HIV-infected individuals on ART, among whom drug-drug interactions are expected. Day-42 adequate clinical and parasitological response (ACPR) and incidence of adverse events was assessed in HIV-infected individuals on efavirenz-based ART with uncomplicated falciparum malaria treated with AL.

METHODS

A prospective, open label, non-randomized, interventional clinical trial was conducted at St Paul's Hospital in northern Zambia, involving 152 patients aged 15-65 years with uncomplicated falciparum malaria, who were on efavirenz-based ART. They received a 3-day directly observed standard treatment of AL and were followed up until day 63. Day-42 polymerase chain reaction (PCR)-corrected ACPRs (95% confidence interval [CI]) were calculated for the intention-to-treat population.

RESULTS

Enrolled patients had a baseline geometric mean (95% CI) parasite density of 1108 (841-1463) parasites/µL; 16.4% (25/152) of the participants had a recurrent malaria episode by day 42. However, PCR data was available for 17 out of the 25 patients who had malaria recurrence. Among all the 17 patients, PCR findings demonstrated malaria re-infection, making the PCR-adjusted day-42 ACPR 100% in the 144 patients who could be evaluated. Even when eight patients with missing PCR data were considered very conservatively as failures, the day-42 ACPR was over 94%. None of the participants, disease or treatment characteristics, including day-7 lumefantrine concentrations, predicted the risk of malaria recurrence by day 42. AL was well tolerated following administration. There were only two cases of grade 3 neutropaenia and one serious adverse event of lobar pneumonia, none of which was judged as probably related to intake of AL.

CONCLUSIONS

AL was well tolerated and efficacious in treating uncomplicated falciparum malaria in HIV co-infected adults on efavirenz-based ART. However, a higher than anticipated proportion of participants experienced malaria re-infection, which highlights the need for additional malaria prevention measures in this sub-population after treatment with AL. Trial registration Pan African Clinical Trials Registry (PACTR): PACTR201311000659400. Registered on 4 October 2013. https://pactr.samrc.ac.za/Search.aspx.