Sabine Bélard

Fixed-Dose Pyronaridine-Artesunate Combination for Treatment of Uncomplicated Falciparum Malaria in Pediatric Patients in Gabon

BACKGROUND The development of novel artemisinin-combination therapies suitable for the treatment of pediatric patients suffering from malaria is a research priority. The aim of this study was to investigate a novel fixed-dose pyronaridine-artesunate combination for the treatment of uncomplicated falciparum malaria in Gabonese patients 2-14 years old. METHODS The study was designed as an open-label dose-escalation study recruiting 60 pediatric patients sequentially in 4 treatment cohorts: study drugs were administered once daily for 3 days, as tablet coformulations (pyronaridine:artesunate ratios of 6:2, 9:3, and 12:4 mg/kg) and as a granule coformulation (pyronaridine:artesunate ratio of 9:3 mg/kg). The primary end points were tolerability, safety, and pharmacokinetics of pyronaridine-artesunate treatment. Efficacy was treated as a secondary outcome measure. RESULTS The drugs had a good tolerability and safety profile, at all dose levels. Pharmacokinetic analysis revealed a dose-dependent increase in the maximum plasma/blood concentration and the area under the curve, as well as comparable relative bioavailability for the granule coformulation. Polymerase chain reaction-corrected cure rates at day 28 were 100% in per-protocol analysis, at all dose levels. CONCLUSIONS Pyronaridine-artesunate is a promising novel artemisinin-combination therapy for pediatric patients with uncomplicated Plasmodium falciparum malaria, and the development of both the tablet and the granule coformulations is warranted.

Adolescence As Risk Factor for Adverse Pregnancy Outcome in Central Africa – A Cross-Sectional Study

Background Sub-Saharan Africa has the highest rates of maternal and neonatal mortality worldwide. Young maternal age at delivery has been proposed as risk factor for adverse pregnancy outcome, yet there is insufficient data from Sub-Saharan Africa. The present study aimed to investigate the influence of maternal adolescence on pregnancy outcomes in the Central African country Gabon. Methodology and Principal Findings Data on maternal age, parity, birth weight, gestational age, maternal Plasmodium falciparum infection, use of bednets, and intake of intermittent preventive treatment of malaria in pregnancy were collected in a cross-sectional survey in 775 women giving birth in three mother-child health centers in Gabon. Adolescent women (≤16 years of age) had a significantly increased risk to deliver a baby with low birth weight in univariable analysis (22.8%, 13/57, vs. 9.3%, 67/718, OR: 2.9, 95% CI: 1.5–5.6) and young maternal age showed a statistically significant association with the risk for low birth weight in multivariable regression analysis after correction for established risk factors (OR: 2.7; 95% CI: 1.1–6.5). In further analysis adolescent women were shown to attend significantly less antenatal care visits than adult mothers (3.3±1.9 versus 4.4±1.9 mean visits, p<0.01, n = 356) and this difference accounted at least for part of the excess risk for low birth weight in adolescents. Conclusion Our data demonstrate the importance of adolescent age as risk factor for adverse pregnancy outcome. Antenatal care programs specifically tailored for the needs of adolescents may be necessary to improve the frequency of antenatal care visits and pregnancy outcomes in this risk group in Central Africa.

A Randomized Controlled Phase Ib Trial of the Malaria Vaccine Candidate GMZ2 in African Children

Background GMZ2 is a fusion protein of Plasmodium falciparum merozoite surface protein 3 (MSP3) and glutamate rich protein (GLURP) that mediates an immune response against the blood stage of the parasite. Two previous phase I clinical trials, one in naïve European adults and one in malaria-exposed Gabonese adults showed that GMZ2 was well tolerated and immunogenic. Here, we present data on safety and immunogenicity of GMZ2 in one to five year old Gabonese children, a target population for future malaria vaccine efficacy trials. Methodology/Principal Findings Thirty children one to five years of age were randomized to receive three doses of either 30 µg or 100 µg of GMZ2, or rabies vaccine. GMZ2, adjuvanted in aluminum hydroxide, was administered on Days 0, 28 and 56. All participants received a full course of their respective vaccination and were followed up for one year. Both 30 µg and 100 µg GMZ2 vaccine doses were well tolerated and induced antibodies and memory B-cells against GMZ2 as well as its antigenic constituents MSP3 and GLURP. After three doses of vaccine, the geometric mean concentration of antibodies to GMZ2 was 19-fold (95%CI: 11,34) higher in the 30 µg GMZ2 group than in the rabies vaccine controls, and 16-fold (7,36) higher in the 100 µg GMZ2 group than the rabies group. Geometric mean concentration of antibodies to MSP3 was 2.7-fold (1.6,4.6) higher in the 30 µg group than in the rabies group and 3.8-fold (1.5,9.6) higher in the 100 µg group. Memory B-cells against GMZ2 developed in both GMZ2 vaccinated groups. Conclusions/Significance Both 30 µg as well as 100 µg intramuscular GMZ2 are immunogenic, well tolerated, and safe in young, malaria-exposed Gabonese children. This result confirms previous findings in naïve and malaria-exposed adults and supports further clinical development of GMZ2. Trial Registration ClinicalTrials.gov NCT00703066

Do paediatric drug formulations of artemisinin combination therapies improve the treatment of children with malaria? A systematic review and meta-analysis

Paediatric formulations of artemisinin combination therapies (ACTs) have recently been developed for the treatment of children with falciparum malaria. Compared with conventional tablet formulations, the new non-tablet preparations have shown equivalent efficacy, safety, and tolerability in individual trials. We aimed to investigate whether objective evidence supports the development and use of paediatric ACTs. A systematic review identified seven studies involving 2515 children that were eligible for meta-analysis. Similar efficacy and safety were seen in pooled analyses of paediatric and conventional formulations. 23 (2.0%) of 1154 patients in the paediatric formulation groups and 19 (1.7%) of 1137 in the tablet formulation groups were not cured (RR 1.27, 95% CI 0.66-2.44). Despite similar overall tolerability, the tolerability of drug administration was improved for paediatric formulations as shown by significantly fewer patients with drug-induced vomiting (93 of 1018 and 114 of 837 patients; risk ratio [RR] 0.78, 95% CI 0.61-0.99), and drug-related gastrointestinal disorders (8 of 545 and 15 of 358 patients; RR 0.36, 95% CI 0.15-0.85). These data provide, for the first time, evidence for improved management of children by use of paediatric formulations, and support the further development and use of paediatric ACTs.

In vitro activity of pyronaridine against Plasmodium falciparum and comparative evaluation of anti-malarial drug susceptibility assays

BackgroundPyronaridine, a Mannich base anti-malarial with high efficacy against drug resistant Plasmodium falciparum, is currently evaluated as a fixed dose combination with artesunate for the treatment of uncomplicated malaria. In this study, the in vitro activity of pyronaridine against clinical isolates of P. falciparum from Lambaréné, Gabon, was assessed in order to obtain baseline data on its activity prior to its future use in routine therapy. Moreover, follow-up assessment on the in vitro activity of chloroquine, artesunate and quinine was performed.MethodsIn vitro response of field isolates of P. falciparum to pyronaridine, chloroquine, artesunate and quinine was assessed using the traditional WHO microtest. In addition, the histidine-rich protein 2 (HRP-2) assay was performed and evaluated for its future implementation for follow-up of drug susceptibility testing.ResultsPyronaridine exhibited a high in vitro activity against P. falciparum, with a geometric mean cut-off concentration of 9.3 nmol/l. Fifty percent effective concentrations were 1.9 nmol/l and 2.0 nmol/l in the WHO microtest and HRP-2 assay, respectively. Results matched closely in vivo findings from a recent clinical trial on pyronaridine-artesunate treatment. One isolate showed diminished sensitivity to artesunate. For chloroquine and quinine resistance levels were comparable to prior studies from Lambaréné. Results from the novel HRP-2 assay corresponded well to those obtained by the WHO microtest.ConclusionPyronaridine is highly active in chloroquine-resistant parasites and seems a promising partner drug for artemisinin-based combination therapy in Africa.

Efficacy and safety of artemisinin combination therapy (ACT) for non-falciparum malaria: a systematic review

BackgroundArtemisinin combination therapy (ACT) is recommended as first-line treatment for uncomplicated Plasmodium falciparum malaria, whereas chloroquine is still commonly used for the treatment of non-falciparum species (Plasmodium vivax, Plasmodium ovale and Plasmodium malariae). A more simplified, more uniform treatment approach across all malaria species is worthwhile to be considered both in endemic areas and for malaria as an imported condition alike.MethodsA PROSPERO-registered systematic review to determine the efficacy and safety of ACT for the treatment of non-falciparum malaria was conducted, following PRISMA guidelines. Without language restrictions, Medline/PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of Science, LILACS, Biosis Previews and the African Index Medicus were searched for studies published up to November 2014.ResultsThe literature search identified 986 reports; 40 publications were found eligible for inclusion, all of them on non-falciparum malaria in endemic areas. Most evidence was available for P. vivax (n = 35). Five clinical trials in total were identified evaluating ACT for P. ovale, P. malariae and Plasmodium knowlesi. Most ACT presentations have high efficacy against P. vivax parasites; artemisinin-based combinations have shorter parasite and fever clearance times compared to chloroquine. ACT is as effective as chloroquine in preventing recurrent parasitaemia before day 28. Artemisinin-based combinations with long half-lives show significantly fewer recurrent parasitaemia up to day 63. The limited evidence available supports both the use of chloroquine and an ACT for P. ovale and P. malariae. ACT seems to be preferable for optimal treatment of P. knowlesi.ConclusionACT is at least equivalent to chloroquine in effectively treating non-falciparum malaria. These findings may facilitate development of simplified protocols for treating all forms of malaria with ACT, including returning travellers. Obtaining comprehensive efficacy and safety data on ACT use for non-falciparum species particularly for P. ovale, P. malariae and P. knowlesi should be a research priority.Trial registrationCRD42014009103

Reduced antibody responses against Plasmodium falciparum vaccine candidate antigens in the presence of Trichuris trichiura

BACKGROUND Helminth infections are highly prevalent in the tropics and may have an effect on immune responses to vaccines due to their immunomodulatory effect. The prevalence of helminth infections in young children, the target group for malaria and most other vaccines, is high. Therefore we assessed the influence of helminth infection on vaccine-induced immune responses in a phase I clinical trial of the malaria vaccine candidate GMZ2. METHODS Twenty Gabonese preschool-age children were vaccinated with GMZ2, a blood stage malaria vaccine candidate. Humoral immune response against the vaccine antigens and parasitological status were assessed. Vaccine-specific antibody concentrations and memory B-cell numbers were compared in worm infected and non-infected participants. RESULTS Antibody response to GMZ2 was 3.4-fold (95% confidence interval: 1.6, 7.4) higher in Trichuris trichiura negative subjects compared to positive participants, whereas immunoglobulin subclass distribution was similar. Memory B-cell response was moderately increased in T. trichiura negative individuals, although the difference was not significant. CONCLUSIONS Future malaria vaccine development programs need to account for worm-mediated hyporesponsiveness of immune reactions.

Prospective evaluation of artemether-lumefantrine for the treatment of non-falciparum and mixed-species malaria in Gabon

BackgroundThe recommendation of artemisinin combination therapy (ACT) as first-line treatment for uncomplicated falciparum malaria is supported by a plethora of high quality clinical trials. However, their recommendation for the treatment of mixed-species malaria and the large-scale use for the treatment of non-falciparum malaria in endemic regions is based on anecdotal rather than systematic clinical evidence.MethodsThis study prospectively observed the efficacy of artemether-lumefantrine for the treatment of uncomplicated non-falciparum or mixed-species malaria in two routine district hospitals in the Central African country of Gabon.ResultsForty patients suffering from uncomplicated Plasmodium malariae, Plasmodium ovale or mixed-species malaria (including Plasmodium falciparum) presenting at the hospital received artemether-lumefantrine treatment and were followed up. All evaluable patients (n = 38) showed an adequate clinical and parasitological response on Day 28 after oral treatment with artemether-lumefantrine (95% confidence interval: 0.91,1). All adverse events were of mild to moderate intensity and completely resolved by the end of study.ConclusionsThis first systematic assessment of artemether-lumefantrine treatment for P. malariae, P. ovale and mixed-species malaria demonstrated a high cure rate of 100% and a favourable tolerability profile, and thus lends support to the practice of treating non-falciparum or mixed-species malaria, or all cases of malaria without definite species differentiation, with artemether-lumefantrine in Gabon.Trial RegistrationClinicalTrials.gov Identifier: NCT00725777

Pyronaridine-artesunate combination therapy for the treatment of malaria.

Purpose of review Pyronaridine–artesunate is among the most promising novel artemisinin combination therapies for the treatment of malaria. A series of clinical phase II and III trials have been conducted for the indications of uncomplicated falciparum and vivax malaria in Africa and Asia. On the basis of these novel data, this review aims to provide an appraisal of current evidence and a perspective for its future role in the antimalarial portfolio. Recent findings Pyronaridine–artesunate demonstrated repeatedly high efficacy in the treatment of vivax and falciparum malaria and noninferiority was established compared to standard comparator regimens. An innovative paediatric drug formulation was developed in parallel to the tablet formulation for the treatment of young children. Pharmacokinetic analysis showed dose linearity, low interindividual variation and absence of a clinically important effect of food on the bioavailability of this drug combination. Overall tolerability and safety data are reassuring; however, further surveillance of safety in special patient populations including young children is warranted. Summary Pyronaridine–artesunate – currently under evaluation by the European Medicines Agency – may become a preferred choice as first-line therapy in malaria endemic regions based on its low cost, long shelf-life, simplified once-daily dosing regimen, proven efficacy against falciparum and vivax malaria, and the parallel clinical development of a paediatric drug formulation.

Efficacy and safety of a new pediatric artesunate-mefloquine drug formulation for the treatment of uncomplicated falciparum malaria in Gabon

ZusammenfassungPädiatrische Medikamentenformulierungen sind ein wichtiger Fortschritt in der Therapie von afrikanischen Kindern, die an Malaria tropica erkrankt sind. In dieser klinischen Studie wurde die Wirksamkeit, Sicherheit und Verträglichkeit einer neuen pädiatrischen Artesunat-Mefloquin Koformulierung im Vergleich mit einer Tablettenformulierung evaluiert. Einundsiebzig pädiatrische Patienten am Albert Schweitzer Spital in Lambaréné, Gabun, die an unkomplizierter Malaria tropica litten, wurden nach Körpergewicht stratifiziert, um mit der pädiatrischen (10 – 20 kg; n = 41) oder der Tabletten-Formulierung (20 – 40 kg; n = 30) therapiert zu werden. Die PCR korrigierte Heilungsrate war 100 % am Tag 28. Die häufigsten Nebenwirkungen waren Erbrechen (17 %), abdominelle Schmerzen (11 %) und Cephalea (17 %). Diese Studie bestätigt die hervorragende Wirksamkeit und gute Verträglichkeit von Artesunat-Mefloquin zur Therapie pädiatrischer Patienten in Afrika.SummaryPediatric drug formulations of artemisinin combination therapies are urgently needed for improving the treatment of children suffering from uncomplicated malaria. The aim of this clinical trial was to evaluate the efficacy, safety and tolerability of a novel pediatric fixed-dose granule formulation of artesunate-mefloquine and a new co-blister tablet formulation. A total of 71 children aged 1–13 years suffering from uncomplicated falciparum malaria were stratified into two groups according to weight: 10–20 kg, pediatric group (n = 41); 20–40 kg, tablet group (n = 30). All the children were treated once daily for three days: the pediatric group received the novel granule formulation, the tablet group received the co-blister tablets. The PCR-corrected cure rate on day 28 was evaluated. There was no reappearance of parasitemia during the follow-up period and the day-28 cure rate was therefore 100% in per-protocol analysis. In intention-to-treat analysis the cure rates were 95% in the pediatric group and 97% in the tablet group. The most frequent adverse events were vomiting (17%), abdominal pain (11%) and headache (17%). This study confirms the excellent efficacy and favorable safety and tolerability profile of a novel pediatric artesunate-mefloquine formulation for treatment in African children.