Meta-Analysis of Data from Four Clinical Trials in the Ivory Coast Assessing the Efficacy of Two Artemisinin-Based Combination Therapies (Artesunate-Amodiaquine and Artemether-Lumefantrine) between 2009 and 2016

The combinations of artemether-lumefantrine (AL) and artesunate-amodiaquine (ASAQ) are used as first-line treatments for uncomplicated malaria in the Ivory Coast. Different studies document the efficacy of two artemisinin-based combination therapies (ACTs) (AL and ASAQ) in the Ivory Coast. However, there is no meta-analysis examining the data set of these studies. The purpose of this work was to determine the prevalence of malaria treatment failure cases in randomized control trials with two artemisinin-based combination therapies (AL versus ASAQ) in the Ivory Coast between 2009 to 2016. This study is a meta-analysis of data from the results of four previous multicenter, open-label, randomized clinical trial studies evaluating the clinical and parasitological efficacy of artemether-lumefantrine and artesunate-amodiaquine conducted between 2009 and 2016 following World Health Organization (WHO) protocol at sentinel sites in the Ivory Coast. These drug efficacy data collected between 2009 and 2016 were analyzed. During these studies, to distinguish between recrudescence and new infection, molecular genotyping of genes encoding merozoite surface protein 1 and 2 was carried out using nested polymerase chain reaction (PCR). A total of 1575 patients enrolled in the four studies, including 768 in the AL arm and 762 in the ASAQ arm, which were fully followed either for 28 days or 42 days according to WHO protocol. The adequate clinical and parasitological response (ACPR) was higher than 95% in the two groups (intention to treat (ITT): AL = 96.59% and ASAQ = 96.81; Per Protocol (PP): AL = 99.48% and ASAQ = 99.61%) after PCR correction at day 28. Aggregate data analysis (2009-2016) showed that at day 28, the proportions of patients with recurrent infection was higher in the AL group (ITT: 3.79%, PP: 3.9%) than in the ASAQ group (ITT: 2.17%, PP: 2.23%). After PCR correction, most treatment failures were classified as new infections (AL group (ITT: 0.13%, PP: 0.13%); ASAQ group (ITT: 0.39%, PP: 0.39%). The recrudescent infections rate was high, at 0.39% compared to 0.13% for ASAQ and AL, respectively, for both ITT and PP, no significant difference. However, the Kaplan-Meier curve of cumulative treatment success showed a significant difference between the two groups after PCR from 2012-2013 (p = 0.032). Overall, ASAQ and AL have been shown to be effective drugs for the treatment of uncomplicated P. falciparum malaria in the study areas, 14 years after deployment of these drugs.

Clinical and In Vitro Resistance of Plasmodium falciparum to Artesunate-Amodiaquine in Cambodia

BACKGROUND

Artesunate-amodiaquine is a potential therapy for uncomplicated malaria in Cambodia.

METHODS

Between September 2016 and January 2017, artesunate-amodiaquine efficacy and safety were evaluated in a prospective, open-label, single-arm observational study at health centers in Mondulkiri, Pursat, and Siem Reap Provinces, Cambodia. Adults and children with microscopically confirmed Plasmodium falciparum malaria received oral artesunate-amodiaquine once daily for 3 days plus single-dose primaquine, with follow-up on days 7, 14, 21, and 28. The primary outcome was day-28 polymerase chain reaction (PCR)-adjusted adequate clinical and parasitological response (ACPR). An amodiaquine parasite survival assay (AQSA) was developed and applied to whole genome sequencing results to evaluate potential amodiaquine resistance molecular markers.

RESULTS

In 63 patients, day-28 PCR-adjusted ACPR was 81.0% (95% confidence interval [CI], 68.9-88.7). Day 3 parasite positivity rate was 44.4% (28/63; 95% CI, 31.9-57.5). All 63 isolates had the K13(C580Y) marker for artemisinin resistance; 79.4% (50/63) had Pfpm2 amplification. The AQSA resistance phenotype (≥45% parasite survival) was expressed in 36.5% (23/63) of isolates and was significantly associated with treatment failure (P = .0020). Pfmdr1 mutant haplotypes were N86/184F/D1246, and Pfcrt was CVIET or CVIDT at positions 72-76. Additional Pfcrt mutations were not associated with amodiaquine resistance, but the G353V mutant allele was associated with ACPR compared to Pfmdr1 haplotypes harboring F1068L or S784L/R945P mutations (P = .030 and P = .0004, respectively).

CONCLUSIONS

For uncomplicated falciparum malaria in Cambodia, artesunate-amodiaquine had inadequate efficacy owing to amodiaquine-resistant P. falciparum. Amodiaquine resistance was not associated with previously identified molecular markers.

Pharmacokinetics and Ex Vivo Antimalarial Activity of Artesunate-Amodiaquine plus Methylene Blue in Healthy Volunteers

High rates of artemisinin-based combination therapy (ACT) failures in the treatment of Plasmodium falciparum malaria in Southeast Asia have led to triple-drug strategies to extend the useful life of ACTs. In this study, we determined whether methylene blue [MB; 3,7-bis(dimethylamino)phenothiazin-5-ium chloride hydrate] alters the pharmacokinetics of artesunate-amodiaquine (ASAQ) and enhances the ex vivo antimalarial activity of ASAQ. In an open-label, randomized crossover design, a single oral dose of ASAQ (200 mg AS/540 mg AQ) alone or with MB (325 mg) was administered to 15 healthy Vietnamese volunteers. Serial blood samples were collected up to 28 days after dosing. Pharmacokinetic properties of the drugs were determined by noncompartmental analysis. After drug administration, plasma samples from seven participants were assessed for ex vivo antimalarial activity against the artemisinin-sensitive MRA1239 and the artemisinin-resistant MRA1240 P. falciparum lines, in vitro MB significantly increased the mean area under the curve of the active metabolite of AS, dihydroartemisinin (1,246 ± 473 versus 917 ± 405 ng·h/ml, P = 0.009) but did not alter the pharmacokinetics of AQ, AS, or desethylamodiaquine. Comparing the antimalarial activities of the plasma samples from the participants collected up to 48 h after ASAQ plus MB (ASAQ+MB) and ASAQ dosing against the MRA1239 and MRA1240 lines, MB significantly enhanced the blood schizontocidal activity of ASAQ by 2.0-fold and 1.9-fold, respectively. The ring-stage survival assay also confirmed that MB enhanced the ex vivo antimalarial activity of ASAQ against MRA1240 by 2.9-fold to 3.8-fold, suggesting that the triple-drug combination has the potential to treat artemisinin-resistant malaria and for malaria elimination. (This study has been registered in the Australian New Zealand Clinical Trials Registry [https://anzctr.org.au/] under registration number ACTRN12612001298808.).

Dihydroartemisinin-piperaquine versus artesunate-amodiaquine for treatment of malaria infection in pregnancy in Ghana: an open-label, randomised, non-inferiority trial

OBJECTIVE

To determine whether dihydroartemisinin-piperaquine (DHA-PPQ) is non-inferior to artesunate-amodiaquine (ASAQ) for treating uncomplicated malaria infection in pregnancy.

METHODS

A total of 417 second/ third trimester pregnant women with confirmed asymptomatic Plasmodium falciparum parasitaemia were randomised to receive DHA-PPQ or ASAQ over 3 days. Women were followed up on days 1, 2, 3, 7, 14, 28 and 42 after treatment start and at delivery for parasitological, haematological, birth outcomes and at 6-week post-partum to ascertain the health status of the babies. Parasitological efficacy (PE) by days 28 and 42 were co-primary outcomes. Analysis was per-protocol (PP) and modified intention-to-treat (ITT). Non-inferiority was declared if the two-sided 95% confidence interval for PE at the endpoints excluded 5% lower efficacy for DHA-PPQ. Secondary outcomes were assessed for superiority.

RESULTS

In PP analysis, PE was 91.6% for DHA-PPQ and 89.3% for ASAQ by day 28 and 89.0% and 86.5%, respectively, by day 42. DHA-PPQ was non-inferior to ASAQ with respect to uncorrected PE [adjusted difference by day 28 (DHA-PPQ-ASAQ); 3.5% (95%CI: -1.5, 8.5); and day 42: 3.9% (95%CI: -2.7, 10.4)]. ITT analysis gave similar results. PCR to distinguish recrudescence and reinfection was unsuccessful. DHA-PPQ recipients had fewer adverse events of vomiting, dizziness, and general weakness compared to ASAQ. Both drugs were well-tolerated, and there was no excess of adverse birth outcomes.

CONCLUSION

DHA-PPQ was non-inferior to ASAQ for treatment of malaria infection during pregnancy. No safety concerns were identified. Our findings contribute to growing evidence that DHA-PPQ is useful for control of malaria in pregnancy.

[Evaluation of the efficacy and safety of three 2-drug combinations for the treatment of uncomplicated Plasmodium falciparum malaria in Senegal: artesunate-amodiaquine, dihydroartemisinin-piperaquine, and artemether-lumefantrine]

BACKGROUND

Since 2006, artemisinin-based combination therapies (ACT) have been used to treat uncomplicated Plasmodium falciparum malaria in Senegal, as recommended by WHO. Recently, decreased parasite clearance with artemisinin derivatives has been reported in Cambodia and Thailand. The effectiveness of artemisinin derivatives in Africa must be monitored. This study was conducted to evaluate the efficacy and the tolerability of three ACT widely used in Senegal.

METHODS

From October 2010 to February 2011, a descriptive and analytical sequential study was conducted in adults and children to evaluate these three combinations: artemether-lumefantrine (AL), artesunate-amodiaquine (ASAQ), and dihydroartemisinin-piperaquine (DHAPQ). The study took place at the health posts of Deggo and Pikine and the health center of Guédiawaye, in the suburbs of Dakar. The primary endpoint was the PCR-corrected adequate clinical and parasitological response (ACPR) at day 28 (D28); the secondary endpoints included ACPR at D42, clearance times for parasites, fever, and gametocytes, and the incidence of adverse events.

RESULTS

The study included 393 patients: 139 in the AL group, 130 in the ASAQ group, and 124 in the DHAPQ group. In the intent-to-treat population, PCR-corrected ACPR at day 28 was 92.8% in the AL, 89.2% in the ASAQ, and 91.1% in the DHAPQ (p = 0.58) groups, and in the per-protocol population, 98.4%, 98.3%, and 100% respectively (p = 0.39). At D42, ACPR was 99.2% in the AL, and 99.1% in each of the ASAQ and DHAPQ arms (p = 1). No early therapeutic failure (ETF) was observed. The combinations were well tolerated, with no serious adverse events reported during the follow-up period.

CONCLUSION

These combinations are still effective and well-tolerated. Continued monitoring is nonetheless essential to detect early artemisinin resistance in Africa.

Adherence to Artemisinin Combination Therapy for the treatment of uncomplicated malaria in the Democratic Republic of the Congo

Between 2011 and 2013 the number of recorded malaria cases had more than doubled, and between 2009 and 2013 had increased almost 4-fold in MSF-OCA (Médecins sans Frontières – Operational Centre Amsterdam) programmes in the Democratic Republic of the Congo (DRC). The reasons for this rise are unclear. Incorrect intake of Artemisinin Combination Therapy (ACT) could result in failure to treat the infection and potential recurrence. An adherence study was carried out to assess whether patients were completing the full course of ACT.

One hundred and eight malaria patients in Shamwana, Katanga province, DRC were visited in their households the day after ACT was supposed to be completed. They were asked a series of questions about ACT administration and the blister pack was observed (if available).

Sixty seven (62.0%) patients were considered probably adherent. This did not take into account the patients that vomited or spat their pills or took them at the incorrect time of day, in which case adherence dropped to 46 (42.6%). The most common reason that patients gave for incomplete/incorrect intake was that they were vomiting or felt unwell (10 patients (24.4%), although the reasons were not recorded for 22 (53.7%) patients). This indicates that there may be poor understanding of the importance of completing the treatment or that the side effects of ACT were significant enough to over-ride the pharmacy instructions.

Adherence to ACT was poor in this setting. Health education messages emphasising the need to complete ACT even if patients vomit doses, feel unwell or their health conditions improve should be promoted.

Impact of retreatment with an artemisinin-based combination on malaria incidence and its potential selection of resistant strains: study protocol for a randomized controlled clinical trial

BACKGROUND

Artemisinin-based combination therapy is currently recommended by the World Health Organization as first-line treatment of uncomplicated malaria. Recommendations were adapted in 2010 regarding rescue treatment in case of treatment failure. Instead of quinine monotherapy, it should be combined with an antibiotic with antimalarial properties; alternatively, another artemisinin-based combination therapy may be used. However, for informing these policy changes, no clear evidence is yet available. The need to provide the policy makers with hard data on the appropriate rescue therapy is obvious. We hypothesize that the efficacy of the same artemisinin-based combination therapy used as rescue treatment is as efficacious as quinine + clindamycin or an alternative artemisinin-based combination therapy, without the risk of selecting drug resistant strains.

DESIGN

We embed a randomized, open label, three-arm clinical trial in a longitudinal cohort design following up children with uncomplicated malaria until they are malaria parasite free for 4 weeks. The study is conducted in both the Democratic Republic of Congo and Uganda and performed in three steps. In the first step, the pre-randomized controlled trial (RCT) phase, children aged 12 to 59 months with uncomplicated malaria are treated with the recommended first-line drug and constitute a cohort that is passively followed up for 42 days. If the patients experience an uncomplicated malaria episode between days 14 and 42 of follow-up, they are randomized either to quinine + clindamycin, or an alternative artemisinin-based combination therapy, or the same first-line artemisinin-based combination therapy to be followed up for 28 additional days. If between days 14 and 28 the patients experience a recurrent parasitemia, they are retreated with the recommended first-line regimen and actively followed up for another 28 additional days (step three; post-RCT phase). The same methodology is followed for each subsequent failure. In any case, all patients without an infection at day 28 are classified as treatment successes and reach a study endpoint. The RCT phase allows the comparison of the safety and efficacy of three rescue treatments. The prolonged follow-up of all children until they are 28 days parasite-free allows us to assess epidemiological-, host- and parasite-related predictors for repeated malaria infection.

TRIAL REGISTRATION

NCT01374581 and PACTR201203000351114.

Clinical tolerability of artesunate-amodiaquine versus comparator treatments for uncomplicated falciparum malaria: an individual-patient analysis of eight randomized controlled trials in sub-Saharan Africa

BACKGROUND

The widespread use of artesunate-amodiaquine (ASAQ) for treating uncomplicated malaria makes it important to gather and analyse information on its tolerability.

METHODS

An individual-patient tolerability analysis was conducted using data from eight randomized controlled clinical trials conducted at 17 sites in nine sub-Saharan countries comparing ASAQ to other anti-malarial treatments. All patients who received at least one dose of the study drug were included in the analysis. Differences in adverse event (AE) and treatment emergent adverse event (TEAE) were analysed by Day 28.

RESULTS

Of the 6,179 patients enrolled (74% <5 years of age), 50% (n = 3,113) received ASAQ, 20% (n = 1,217) another ACT, and 30% (n = 1,849) a non-ACT (combination or single-agent) treatment. Overall, 8,542 AEs were recorded. The proportion of patients experiencing at least one gastro-intestinal AE on ASAQ was 43% (and higher than that with artemether-lumefantrine and dihydroartemisinin-piperaquine at two sites), and was 23% for any other AEs (not different from other treatments). Specifically, the risk of diarrhoea, vomiting, cough and weakness was lower with artemether-lumefantrine; artemether-lumefantrine and dihydroartemisinin-piperaquine carried a higher risk of pruritus, chloroquine-SP had a higher risk of nausea. Parasitological recurrence increased the risk of occurrence of any AE. No other difference was detected. Comparing AE to TEAE in patients who had pre-treatment occurrence and grades of intensity recorded, AEs were significantly more related to the pre-treatment prevalence of the symptom (p = 0.001, Fisher test); AEs overestimated TEAEs by a factor ranging from none to five-fold. The overall incidence of serious AEs (SAEs) with ASAQ was nine per 1,000 (29/3,113) and mortality was one per 1,000 (three deaths, none drug-related); both were similar to other treatments.

CONCLUSION

ASAQ was comparatively well-tolerated. Safety information is important, and must be collected and analysed in a standardized way. TEAEs are a more objective measure of treatment-induced toxicity.