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

Safety and efficacy of pyronaridine-artesunate paediatric granules in the treatment of uncomplicated malaria in children: insights from randomized clinical trials and a real-world study

BACKGROUND

Children are particularly at risk of malaria. This analysis consolidates the clinical data for pyronaridine-artesunate (PA) paediatric granules in children from three randomized clinical trials and a real-world study (CANTAM).

METHODS

An integrated safety analysis of individual patient data from three randomized clinical trials included patients with microscopically-confirmed Plasmodium falciparum, body weight ≥ 5 kg to < 20 kg, who received at least one dose of study drug (paediatric safety population). PA was administered once daily for 3 days; two trials included the comparator artemether-lumefantrine (AL). PCR-adjusted day 28 adequate clinical and parasitological response (ACPR) was evaluated. Real-world PA granules safety and effectiveness was also considered.

RESULTS

In the integrated safety analysis, 63.9% (95% CI 60.2, 67.4; 426/667) of patients had adverse events following PA and 62.0% (95% CI 56.9, 66.9; 222/358) with AL. Vomiting was more common with PA (7.8% [95% CI 6.0, 10.1; 52/667]) than AL (3.4% [95% CI 1.9, 5.8; 12/358]), relative risk 2.3 (95% CI 1.3, 4.3; P = 0.004), occurring mainly following the first PA dose (6.7%, 45/667), without affecting re-dosing or adherence. Prolonged QT interval occurred less frequently with PA (3.1% [95% CI 2.1, 4.8; 21/667]) than AL (8.1% [95% CI 5.7, 11.4; 29/358]), relative risk 0.39 (95% CI 0.22, 0.67; P = 0.0007). In CANTAM, adverse events were reported for 17.7% (95% CI 16.3, 19.2; 460/2599) of patients, most commonly vomiting (5.4% [95% CI 4.6, 6.4; 141/2599]), mainly following the first dose, (4.5% [117/2599]), with all patients successfully re-dosed, and pyrexia (5.4% [95% CI 4.6, 6.3; 140/2599]). In the two comparative clinical trials, Day 28 ACPR in the per-protocol population for PA was 97.1% (95% CI 94.6, 98.6; 329/339) and 100% (95% CI 99.3, 100; 514/514) versus 98.8% (95% CI 95.7, 99.9; 165/167) and 98.4% (95% CI 95.5, 99.7; 188/191) for AL, respectively. In CANTAM, PA clinical effectiveness was 98.0% (95% CI 97.3, 98.5; 2273/2320).

CONCLUSIONS

Anti-malarial treatment with PA paediatric granules administered once daily for 3 days was well tolerated in children and displayed good clinical efficacy in clinical trials, with effectiveness confirmed in a real-world study. Trial registration Clinicaltrials.gov: SP-C-003-05: identifier NCT00331136; SP-C-007-07: identifier NCT0541385; SP-C-021-15: identifier NCT03201770. Pan African Clinical Trials Registry: SP-C-013-11: identifier PACTR201105000286876.

Exploring the feasibility of introducing triple artemisinin-based combination therapy in the malaria treatment policy in Vietnam

BACKGROUND

This study investigates the processes regarding changing malaria treatment policies in Vietnam. Moreover, it explores the feasibility of introducing triple artemisinin-based combination therapy (TACT) in Vietnam to support the national malaria control and elimination plan.

METHODS

Data were collected via 12 in-depth interviews with key stakeholders, combined with a review of policy documents.

RESULTS

TACT is considered as a useful backup strategy in case future treatment failures with current artemisinin-based combination therapy (ACT) would occur. Moreover, TACT is also considered as a promising strategy to prevent the re-establishment of malaria. However, regulatory procedures and implementation timelines for TACT were expected to be lengthy. Therefore, strategies to engage national decision-makers, regulators, and suppliers should be initiated soon, stipulating the benefits of TACT deployment. In Vietnam, a procedure to apply for an import permit without registration that has previously been applied to the introduction of artesunate-pyronaridine was proposed to accelerate the introduction of TACT. Global-level support through the World Health Organization recommendations and prequalification were considered critical for supporting the introduction of TACT in Vietnam.

CONCLUSIONS

Appropriate approach strategies and early stakeholder engagement will be needed to accelerate the introduction of TACT in Vietnam.

Pyronaridine: a review of its clinical pharmacology in the treatment of malaria

Pyronaridine-artesunate was recently strongly recommended in the 2022 update of the WHO Guidelines for the Treatment of Malaria, becoming the newest artemisinin-based combination therapy (ACT) for both uncomplicated Plasmodium falciparum and Plasmodium vivax malaria. Pyronaridine-artesunate, available as a tablet and paediatric granule formulations, is being adopted in regions where malaria treatment outcome is challenged by increasing chloroquine resistance. Pyronaridine is an old antimalarial agent that has been used for more than 50 years as a blood schizonticide, which exerts its antimalarial activity by interfering with the synthesis of the haemozoin pigment within the Plasmodium digestive vacuole. Pyronaridine exhibits a high blood-to-plasma distribution ratio due to its tendency to accumulate in blood cells. This feature is believed to play a crucial role in its pharmacokinetic (PK) properties and pharmacological activity. The PK characteristics of pyronaridine include rapid oral absorption, large volumes of distribution and low total body clearance, resulting in a long terminal apparent half-life. Moreover, differences in PK profiles have been observed between healthy volunteers and malaria-infected patients, indicating a potential disease-related impact on PK properties. Despite a long history, there is only limited knowledge of the clinical PK and pharmacodynamics of pyronaridine, particularly in special populations such as children and pregnant women. We here provide a comprehensive overview of the clinical pharmacology of pyronaridine in the treatment of malaria.

Efficacy and safety of pyronaridine-artesunate versus artemether-lumefantrine in the treatment of acute uncomplicated malaria in children in South-West Nigeria: an open-labelled randomized controlled trial

BACKGROUND

In Nigeria, declining responsiveness to artemether-lumefantrine (AL), the artemisinin-based combination therapy (ACT) of choice since 2005, has been reported. Pyronaridine-artesunate (PA) is a newer fixed-dose ACT recently prequalified by the WHO for the treatment of uncomplicated falciparum malaria. However, PA data from the Nigerian pediatric population is scarce. Therefore, the efficacy and safety of PA and AL using the WHO 28-day anti-malarial therapeutic efficacy study protocol in Ibadan, southwest Nigeria, were compared.

METHODS

In an open-labelled, randomized, controlled clinical trial, 172 children aged 3-144 months with a history of fever and microscopically confirmed uncomplicated Plasmodium falciparum malaria were enrolled in southwest Nigeria. Enrollees were randomly assigned to receive PA or AL at standard dosages according to body weight for 3 days. Venous blood was obtained for hematology, blood chemistry, and liver function tests on days 0, 3, 7, and 28 as part of the safety evaluation.

RESULTS

165 (95.9%) of the enrolled individuals completed the study. About half (52.3%; 90/172) of enrollees were male. Eighty-seven (50.6%) received AL, while 85 (49.4%) received PA. Day 28, adequate clinical and parasitological response for PA was 92.7% [(76/82) 95% CI 83.1, 95.9] and 71.1% [(59/83) 95% CI 60.4, 79.9] for AL (0.001). Fever and parasite clearance were similar in both groups. Two of six and eight of 24 parasite recurrences were observed among PA- and AL-treated children, respectively. PCR-corrected Day-28 cure rates for PA were 97.4% (76/78) and 88.1% (59/67) for AL (= 0.04) in the per-protocol population after new infections were censored. Hematological recovery at day 28 was significantly better among PA-treated patients (34.9% 2.8) compared to those treated with AL (33.1% 3.0) (0.002). Adverse events in both treatment arms were mild and similar to the symptoms of malaria infection. Blood chemistry and liver function tests were mostly within normal limits, with an occasional marginal rise.

CONCLUSION

PA and AL were well-tolerated. PA was significantly more efficacious than AL in both the PCR-uncorrected and PCR-corrected per-protocol populations during this study. The results of this study support the inclusion of PA in the anti-malarial treatment guidelines in Nigeria.

RETROSPECTIVE TRIAL REGISTRATION

Clinicaltrials.gov: NCT05192265.

Post-treatment haemolysis is common following oral artemisinin combination therapy of uncomplicated malaria in travellers

BACKGROUND

Artemisinin combination therapy (ACT) for the treatment of malaria is highly effective, well tolerated and safe. Episodes of delayed hemolysis occur in up to 57.9% of patients with severe malaria treated with intravenous artesunate, mainly caused by 'pitting' of infected red blood cells (RBCs) in the spleen and delayed loss of these once-infected RBCs (oiRBCs). Several reports indicate that post-treatment hemolysis (PTH) also occurs in uncomplicated malaria treated with oral ACT, calling for systematic investigation.

METHODS

Prospective observational study to identify the proportion of patients with PTH after oral ACT, defined as increased lactate dehydrogenase activity and low haptoglobin level on day 14 after treatment. Patients were enrolled at two study centres in Germany and Italy. Study visits took place on days 1, 3, 7, 14, 28. Laboratory investigations included extended clinical routine laboratory tests, quantitative P.f.-HRP2, anti-RBC antibodies, and oiRBCs. State of semi-immunity to malaria was assessed from childhood and ongoing exposure to Plasmodium spp. as per patient history.

RESULTS

A total of 134 patients with uncomplicated malaria and 3-day ACT treatment were recruited. Thirty-seven (37.4%) of 99 evaluable patients with P.f. and none of nine patients with non-P.f. malaria exhibited PTH on d14. Patients with PTH had higher initial parasitaemia, higher oiRBC counts on d3, and a 10-fold decrease in oiRBCs between d7 and d14 compared to patients without PTH. In patients with PTH, loss of haemoglobin (Hb) was 4-fold greater in non-Africans than in Africans (-1.3 vs -0.3 g/dl). Semi-immune African patients with PTH showed markedly increased erythropoiesis on d14 compared to not semi-immune African and non-African patients with PTH.

CONCLUSIONS

PTH is common in patients with uncomplicated malaria and oral ACT. While the observed loss of Hb will not be clinically relevant in most cases, it could aggravate pre-existing anaemia and warrants follow-up examinations in populations at risk.

Artesunate: A review of its therapeutic insights in respiratory diseases

BACKGROUND

Artesunate, as a semi-synthetic artemisinin derivative of sesquiterpene lactone, is widely used in clinical antimalarial treatment due to its endoperoxide group. Recent studies have found that artesunate may have multiple pharmacological effects, indicating its significant therapeutic potential in multiple respiratory diseases.

PURPOSE

This review aims to summarize proven and potential therapeutic effects of artesunate in common respiratory disorders.

STUDY DESIGN

This review summarizes the pharmacological properties of artesunate and then interprets the function of artesunate in various respiratory diseases in detail, such as bronchial asthma, chronic obstructive pulmonary disease, lung injury, lung cancer, pulmonary fibrosis, coronavirus disease 2019, etc., on different target cells and receptors according to completed and ongoing in silico, in vitro, and in vivo studies (including clinical trials).

METHODS

Literature was searched in electronic databases, including Pubmed, Web of Science and CNKI with the primary keywords of 'artesunate', 'pharmacology', 'pharmacokinetics', 'respiratory disorders', 'lung', 'pulmonary', and secondary search terms of 'Artemisia annua L.', 'artemisinin', 'asthma', 'chronic obstructive lung disease', 'lung injury', 'lung cancer', 'pulmonary fibrosis', 'COVID-19' and 'virus' in English and Chinese. All experiments were included. Reviews and irrelevant studies to the therapeutic effects of artesunate on respiratory diseases were excluded. Information was sort out according to study design, subject, intervention, and outcome.

RESULTS

Artesunate is promising to treat multiple common respiratory disorders via various mechanisms, such as anti-inflammation, anti-oxidative stress, anti-hyperresponsiveness, anti-proliferation, airway remodeling reverse, induction of cell death, cell cycle arrest, etc. CONCLUSION: Artesunate has great potential to treat various respiratory diseases.

Prospective observational study to evaluate the clinical and biological safety profile of pyronaridine-artesunate in a rural health district in Burkina Faso

The assessment in real‐life conditions of the safety and efficacy of new antimalarial drugs is of greatest interest. This study aimed to monitor and evaluate both clinical and biological safety of pyronaridine‐artesunate (PA) in real‐life conditions in Burkina Faso's health system. This was a single‐arm, open‐label study, where patients attending Nanoro health facilities with uncomplicated malaria were consented to be part of a cohort event monitoring (CEM). At inclusion (day‐0), PA was administered orally once a day for 3 days. Patients spontaneous reported any clinical adverse events (AEs) occurring within 28 days following the treatment. Additionally, the study focused on AEs of special interest (AESI), namely clinical signs related to hepatotoxicity and increased alanine aminotransferase (ALT) and aspartate aminotransferase (AST). A nested subset of patients with blood sample collection at day‐0 and day‐7 were monitored to investigate the effect of PA on biochemistry parameters. From September 2017 to October 2018, 2786 patients were treated with PA. About 97.8% (2720/2786) of patients did not report any AE. The most commonly reported events were respiratory, thoracic, and mediastinal disorders (8.3 per 1000), infections and infestations (7.9 per 1000), and gastrointestinal disorders (7.2 per 1000). No clinical or biological hepatotoxicity event related to PA was reported during the follow‐up. Changes in biochemistry parameters remained within laboratory reference ranges. The study showed that PA is a well‐tolerated drug and should be considered as a good option by malaria control programs in countries where existing first‐line antimalarial drugs are continuously threatened by the emergence of drug resistance.

Pyronaridine-artesunate for treating uncomplicated Plasmodium falciparum malaria

BACKGROUND

The World Health Organization (WHO) recommends artemisinin-based combination therapies (ACTs) to treat uncomplicated Plasmodium falciparum malaria. Concerns about artemisinin resistance have led to global initiatives to develop new partner drugs to protect artemisinin derivatives in ACT. Pyronaridine-artesunate is a novel ACT.

OBJECTIVES

To evaluate the efficacy of pyronaridine-artesunate compared to alternative ACTs for treating people with uncomplicated P falciparum malaria, and to evaluate the safety of pyronaridine-artesunate and other pyronaridine treatments compared to alternative treatments.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register; Cochrane Central Register of Controlled Trials (CENTRAL), published in the Cochrane Library; MEDLINE; Embase; and LILACS. We also searched ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform, and the ISRCTN registry for ongoing or recently completed trials. The date of the last search was 27 October 2021.

SELECTION CRITERIA

For the efficacy analysis, we included randomized controlled trials (RCTs) of pyronaridine-artesunate for treating uncomplicated P falciparum malaria. For the safety analysis, we included RCTs that used pyronaridine alone or in combination with any other antimalarials. In addition to these analyses, we conducted a separate systematic review summarizing data on safety from non-randomized studies (NRS) of any patient receiving pyronaridine (NRS safety review).  DATA COLLECTION AND ANALYSIS: Two review authors independently extracted all data and assessed the certainty of the evidence. We meta-analysed data to calculate risk ratios (RRs) for treatment failures between comparisons, and for safety outcomes between and across comparisons.

MAIN RESULTS

We included 10 relevant RCTs. Seven RCTs were co-funded by Shin Poong Pharmaceuticals, and three were funded by government agencies. Efficacy analysis (RCTs) For the efficacy analysis, we identified five RCTs comprising 5711 participants. This included 4465 participants from 13 sites in Africa, and 1246 participants from five sites in Asia. The analysis included 541 children aged less than five years. Overall, pyronaridine-artesunate had a polymerase chain reaction (PCR)-adjusted treatment failure rate of less than 5%. We evaluated pyronaridine-artesunate versus the following. • Artemether-lumefantrine. Pyronaridine artesunate may perform better for PCR-adjusted failures at day 28 (RR 0.59, 95% confidence interval (CI) 0.26 to 1.31; 4 RCTs, 3068 participants, low-certainty evidence); for unadjusted failures at day 28 (RR 0.27, 95% CI 0.13 to 0.58; 4 RCTs, 3149 participants, low-certainty evidence); and for unadjusted failures at day 42 (RR 0.61, 95% CI 0.46 to 0.82; 4 RCTs, 3080 participants, low-certainty evidence). For PCR-adjusted failures at day 42, there may be little or no difference between groups (RR 0.86, 95% CI 0.49 to 1.51; 4 RCTs, 2575 participants, low-certainty evidence). • Artesunate-amodiaquine. Pyronaridine artesunate may perform better for PCR-adjusted failures at day 28 (RR 0.55, 95% CI 0.11 to 2.77; 1 RCT, 1245 participants, low-certainty evidence); probably performs better for unadjusted failures at day 28 (RR 0.49, 95% CI 0.30 to 0.81; 1 RCT, 1257 participants, moderate-certainty evidence); may make little or no difference for PCR-adjusted failures at day 42 (RR 0.98, 95% CI 0.20 to 4.83; 1 RCT, 1091 participants, low-certainty evidence); and probably makes little or no difference for unadjusted failures at day 42 (RR 0.98, 95% CI 0.78 to 1.23; 1 RCT, 1235 participants, moderate-certainty evidence). • Mefloquine plus artesunate. Pyronaridine artesunate may perform better for PCR-adjusted failures at day 28 (RR 0.37, 95% CI 0.13 to 1.05; 1 RCT, 1117 participants, low-certainty evidence); probably performs better for unadjusted failures at day 28 (RR 0.36, 95% CI 0.17 to 0.78; 1 RCT, 1120 participants, moderate-certainty evidence); may make little or no difference for unadjusted failures at day 42 (RR 0.84, 95% CI 0.54 to 1.31; 1 RCT, 1059 participants, low-certainty evidence); but may lead to higher PCR-adjusted failures at day 42 (RR 1.80, 95% CI 0.90 to 3.57; 1 RCT, 1037 participants, low-certainty evidence). Safety analysis (RCTs) For the RCT safety analysis, we identified eight RCTs, one of which was delineated by study site, comparing pyronaridine-artesunate to other antimalarials. Pyronaridine-artesunate was associated with raised liver enzymes compared to other antimalarials: alanine aminotransferase (ALT) (RR 3.59, 95% CI 1.76 to 7.33; 8 RCTS, 6669 participants, high-certainty evidence) and aspartate transaminase (AST) (RR 2.22, 95% CI 1.12 to 4.41; 8 RCTs, 6669 participants, moderate-certainty evidence). No such effect was demonstrated with bilirubin (RR 1.03, 95% CI 0.49 to 2.18; 7 RCTs, 6384 participants, moderate-certainty evidence). There was one reported case in which raised ALT occurred with raised bilirubin. No study reported severe drug-induced liver injury. Electrocardiograph (ECG) abnormalities were less common with pyronaridine-artesunate compared to other antimalarials. We identified no other safety concerns. NRS safety review A review on safety in NRS allowed us to increase the population within which safety was assessed. We included seven studies with 9546 participants: five single-arm observational studies, one cohort event monitoring study, and one dose-escalation study. All studies provided data on adverse event frequency, with a small number of participants experiencing serious adverse events and adverse effects related to pyronaridine: serious adverse events average 0.37%; drug-related 9.0%. In two studies reporting elevations in liver enzymes, small percentages of participants (2.4% and 14.1% respectively) experienced increases in either ALT, AST, or bilirubin on day 7; however, these were small increases that returned to normal by day 42.  AUTHORS' CONCLUSIONS: Pyronaridine-artesunate was efficacious against uncomplicated P falciparum malaria; achieved a PCR-adjusted treatment failure rate of less than 5% at days 28 and 42; and may be at least as good as, or better than, other marketed ACTs. Pyronaridine-artesunate increases the risk of episodes of abnormally raised ALT. The observational data did not signal an excess of clinically important adverse effects.

Effectiveness of pyronaridine-artesunate against Plasmodium malariae, Plasmodium ovale spp, and mixed-Plasmodium infections: a post-hoc analysis of the CANTAM-Pyramax trial

Background

Methods

Findings

Interpretation

Funding

Efficacy, Safety and Tolerability of Pyronaridine-artesunate in Asymptomatic Malaria-infected Individuals: a Randomized Controlled Trial

BACKGROUND

Pyronaridine-artesunate (PA) is a registered artemisinin-based combination therapy, potentially useful for mass drug administration campaigns. However, further data are needed to evaluate its efficacy, safety and tolerability as full or incomplete treatment in asymptomatic Plasmodium falciparum-infected individuals.

METHODS

This phase II, multi-center, open label, randomized clinical trial was conducted in The Gambia and Zambia. Participants with microscopically confirmed asymptomatic P. falciparum infection were randomly assigned (1:1:1) to receive a 3-day, 2-day, or 1-day treatment regimen of PA (180:60 mg), dosed according to bodyweight. The primary efficacy outcome was polymerase chain reaction (PCR)-adjusted adequate parasitological response (APR) at day 28 in the per-protocol population.

RESULTS

A total of 303 participants were randomized. Day 28 PCR-adjusted APR was 100% for both the 3-day (98/98) and 2-day regimens (96/96), and 96.8% (89/94) for the 1-day regimen. Efficacy was maintained at 100% until day 63 for the 3-day and 2-day regimens but declined to 94.4% (84/89) with the 1-day regimen. Adverse event frequency was similar between the 3-day (51.5% [52/101]), 2-day (52.5% [52/99]), and 1-day (54.4% [56/103]) regimens; the majority of adverse events were of grade 1 or 2 severity (85% [136/160]). Asymptomatic, transient increases (>3 times the upper limit of normal) in alanine aminotransferase/aspartate aminotransferase were observed for 6/301 (2.0%) participants.

CONCLUSIONS

PA had high efficacy and good tolerability in asymptomatic P. falciparum-infected individuals, with similar efficacy for the full 3-day and incomplete 2-day regimens. Although good adherence to the 3-day regimen should be encouraged, these results support the further investigation of PA for mass drug administration campaigns.

CLINICAL TRIALS REGISTRATION

NCT03814616.

Pharmacotherapy for artemisinin-resistant malaria

INTRODUCTION

Malaria, the most devastating parasitic disease, is currently treated with artemisinin-based combination therapies (ACTs). Unfortunately, some ACTs are unable to rapidly clear Plasmodium falciparum parasites from the blood stream and are failing to cure malaria patients; a problem, so far, largely confined to Southeast Asia. There is a fear of resistant Plasmodium falciparum emerging in other parts of the world including Sub-Saharan Africa. Strategies for alternative treatments, ideally non-artemisinin based, are needed.

AREAS COVERED

This narrative review gives an overview of approved antimalarials and of some compounds in advanced drug development that could be used when an ACT is failing. The selection was based on a literature search in PubMed and WHO notes for malaria treatment.

EXPERT OPINION

The ACT drug class can still cure malaria in malaria endemic regions. However, the appropriate ACT drug should be chosen considering the background resistance of the partner drug of the local parasite population. Artesunate-pyronaridine, the 'newest' recommended ACT, and atovaquone-proguanil are, so far, effective, and safe treatments for uncomplicated falciparum malaria. Therefore, all available ACTs should be safeguarded from parasite resistance and the development of new antimalarial drug classes needs to be accelerated.

Pyronaridine-artesunate real-world safety, tolerability, and effectiveness in malaria patients in 5 African countries: A single-arm, open-label, cohort event monitoring study

BACKGROUND

In Phase II/III randomized controlled clinical trials for the treatment of acute uncomplicated malaria, pyronaridine-artesunate demonstrated high efficacy and a safety profile consistent with that of comparators, except that asymptomatic, mainly mild-to-moderate transient increases in liver aminotransferases were reported for some patients. Hepatic safety, tolerability, and effectiveness have not been previously assessed under real-world conditions in Africa.

METHODS AND FINDINGS

This single-arm, open-label, cohort event monitoring study was conducted at 6 health centers in Cameroon, Democratic Republic of Congo, Gabon, Ivory Coast, and Republic of Congo between June 2017 and April 2019. The trial protocol as closely as possible resembled real-world clinical practice for the treatment of malaria at the centers. Eligible patients were adults or children of either sex, weighing at least 5 kg, with acute uncomplicated malaria who did not have contraindications for pyronaridine-artesunate treatment as per the summary of product characteristics. Patients received fixed-dose pyronaridine-artesunate once daily for 3 days, dosed by body weight, without regard to food intake. A tablet formulation was used in adults and adolescents and a pediatric granule formulation in children and infants under 20 kg body weight. The primary outcome was the hepatic event incidence, defined as the appearance of the clinical signs and symptoms of hepatotoxicity confirmed by a >2× rise in alanine aminotransferase/aspartate aminotransferase (ALT/AST) versus baseline in patients with baseline ALT/AST >2× the upper limit of normal (ULN). As a secondary outcome, this was assessed in patients with ALT/AST >2× ULN prior to treatment versus a matched cohort of patients with normal baseline ALT/AST. The safety population comprised 7,154 patients, of mean age 13.9 years (standard deviation (SD) 14.6), around half of whom were male (3,569 [49.9%]). Patients experienced 8,560 malaria episodes; 158 occurred in patients with baseline ALT/AST elevations >2×ULN. No protocol-defined hepatic events occurred following pyronaridine-artesunate treatment of malaria patients with or without baseline hepatic dysfunction. Thus, no cohort comparison could be undertaken. Also, as postbaseline clinical chemistry was only performed where clinically indicated, postbaseline ALT/AST levels were not systematically assessed for all patients. Adverse events of any cause occurred in 20.8% (1,490/7,154) of patients, most frequently pyrexia (5.1% [366/7,154]) and vomiting (4.2% [303/7,154]). Adjusting for Plasmodium falciparum reinfection, clinical effectiveness at day 28 was 98.6% ([7,369/7,746] 95% confidence interval (CI) 98.3 to 98.9) in the per-protocol population. There was no indication that comorbidities or malnutrition adversely affected outcomes. The key study limitation was that postbaseline clinical biochemistry was only evaluated when clinically indicated.

CONCLUSIONS

Pyronaridine-artesunate had good tolerability and effectiveness in a representative African population under conditions similar to everyday clinical practice. These findings support pyronaridine-artesunate as an operationally useful addition to the management of acute uncomplicated malaria.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03201770.

Efficacy and safety of artemisinin-based combination therapies for the treatment of uncomplicated malaria in pediatrics: a systematic review and meta-analysis

BACKGROUND

Malaria is a major cause of morbidity and mortality in pediatrics in malaria endemic areas. Artemisinin-based combination therapies (ACTs) are the drugs of choice for malaria management particularly across malaria-endemic countries. This systematic review and meta-analysis was performed to assess efficacy and safety of ACTs for uncomplicated malaria in pediatric populations.

METHODS

A body of evidence was searched for published ACT trials until March 06, 2020. The search was focused on efficacy and safety studies of ACTs for uncomplicated malaria in pediatrics. PubMed library was searched using best adapted search terms after multiple trials. References were exported to the endnote library and then to Covidence for screening. Data was extracted using the Covidence platform. The per-protocol analysis report for the efficacy and the intention-to-treat analysis for the safety were synthesized. Met-analysis was carried using Open Meta-Analyst software. Random effects model was applied and the heterogeneity of studies was evaluated using I2 statistic.

RESULTS

Nineteen studies were included in the final analysis. Overall, crude, PCR-corrected P. falciparum malaria treatment success rate was 96.3 and 93.9% for day 28 and 42, respectively. In the subgroup analysis, PCR-corrected adequate clinical and parasitological response (ACPR) of dihydroartemisinin-piperaquine (DP) was 99.6% (95% CI: 99.1 to 100%, I2 = 0%; 4 studies) at day 28 and 99.6% (95% CI of 99 to 100%, I2 = 0%; 3 studies) at day 42. Nine studies reported ACT related adverse drug reactions (ADR) (8.3%, 356/4304). The reported drug related adverse reactions ranged from 1.8% in DP (two studies) to 23.3% in artesunate-pyronaridine (AP). Gastrointestinal symptoms were the most common ACT related adverse effects, and all ADRs were reported to resolve spontaneously.

CONCLUSION

ACTs demonstrated a high crude efficacy and tolerability against P. falciparum. The high treatment success and tolerability with low heterogeneity conferred by DP has implication for policy makers who plan the use of ACTs for uncomplicated falciparum malaria treatment in pediatrics.

Development of sustainable research excellence with a global perspective on infectious diseases: Centre de Recherches Médicales de Lambaréné (CERMEL), Gabon

Medical research in sub-Saharan Africa is of high priority for societies to respond adequately to local health needs. Often enough it remains a challenge to build up capacity in infrastructure and human resources to highest international standards and to sustain this over mid-term to long-term periods due to difficulties in obtaining long-term institutional core funding, attracting highly qualified scientists for medical research and coping with ever changing structural and political environments. The Centre de Recherches Médicales de Lambaréné (CERMEL) serves as model for how to overcome such challenges and to continuously increase its impact on medical care in Central Africa and beyond. Starting off as a research annex to the Albert Schweitzer Hospital in Lambaréné, Gabon, it has since then expanded its activities to academic and regulatory clinical trials for drugs, vaccines and diagnostics in the field of malaria, tuberculosis, and a wide range of poverty related and neglected tropical infectious diseases. Advancing bioethics in medical research in Africa and steadily improving its global networks and infrastructures, CERMEL serves as a reference centre for several international consortia. In close collaboration with national authorities, CERMEL has become one of the main training hubs for medical research in Central Africa. It is hoped that CERMEL and its leitmotiv “to improve medical care for local populations” will serve as an inspiration to other institutions in sub-Saharan Africa to further increase African capacity to advance medicine.

Systematic review of artesunate pharmacokinetics: Implication for treatment of resistant malaria

BACKGROUND

Artesunate (ART) is an artemisinin derivative used as monotherapy for the treatment of severe malaria and in combination with a partner drug for non-severe malaria. Resistance of malaria parasites to artemisinins have emerged in Southeast Asia. Adjustment of drug regimen may be an option to prevent therapeutic failures considering the relative favourable safety profile of ART high doses.

METHODS

For that purpose, a systematic review was done using PubMed, Scopus and Web of Science databases. All studies on ART and DHA pharmacokinetic post-administration of artesunate in human patients or volunteers were included. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist 2009 was used.

FINDINGS

Fifty studies exploring oral, intravenous, rectal, and intramuscular route (1470 persons, volunteers and patients) were included. Correlations between artesunate doses and C_max or AUC_0-∞ of dihydroartemisinin (DHA) and DHA+ART were evaluated. This correlation was good (R²>0.9) using intravenous (IV) route. DHA and ART+DHA average concentrations (Cav) were well above estimated in vivo half-maximal effective concentration (EC₅₀) for intravenous route, but this was not the case for oral route.

INTERPRETATION

The favorable Cav/EC₅₀ ratio for IV route provides evidence that IV ART will remain efficient even in the case of increased resistance level, whereas for the oral route, a two-fold increase in EC₅₀ may lead to therapeutic failures, thus providing a rationale for oral dose escalation. Considering the inter-individual variability of ART pharmacokinetic, Therapeutic Drug Monitoring through antimalarial stewardship activities is needed to optimize drug exposure and avoid resistance development.

Efficacy and Safety of Pyronaridine-Artesunate plus Single-Dose Primaquine for Treatment of Uncomplicated Plasmodium falciparum Malaria in Eastern Cambodia

In Cambodia, multidrug-resistant Plasmodium falciparum undermines the treatment of uncomplicated malaria, and new therapeutic options are needed. Pyronaridine-artesunate has not previously been evaluated in eastern Cambodia. We conducted a single-arm, open-label, prospective study between July and December 2017 at the Koh Gnek (Mondulkiri) and Veun Sai (Rattanakiri) health centers in eastern Cambodia. Eligible patients were aged ≥7 years (females, ages 12 to 18 years, were excluded), weighing ≥20 kg, with microscopically confirmed P. falciparum monoinfection and fever. Oral pyronaridine-artesunate was administered once daily for 3 days, dosed according to body weight, plus a single dose of primaquine on day 0. Sixty patients were recruited to Koh Gnek, and 61 patients were recruited to Veun Sai. The primary outcomes, i.e., the day 42 PCR-adjusted adequate clinical and parasitological responses (ACPRs), were 98.3% (95% confidence interval [CI], 88.4 to 99.8) in Koh Gnek and 96.7% (95% CI, 87.3 to 99.2) in Veun Sai (Kaplan-Meier). In a per-protocol analysis, the proportions of patients with day 42 PCR-adjusted ACPRs were 98.3% (57/58; 95% CI, 90.8 to 100.0) at Koh Gnek and 96.7% (58/60; 95% CI, 88.5 to 99.6) at Veun Sai. The Kelch13 (C580Y) mutation was present in 70.0% (77/110) of isolates. The copy numbers were increased in 61.3% (73/119) of isolates for Pfpm2 and in 1.7% (2/119) for Pfmdr1 There was no relationship between outcome and the 50% inhibitory concentration of pyronaridine. Adverse events were consistent with malaria, and there were no serious adverse events. Pyronaridine-artesunate has high efficacy in eastern Cambodia and could be used to increase the diversity of antimalarial therapy in the region. (This study is registered in the Australian New Zealand Clinical Trials Registry [ANZCTR] under no. ACTRN12618001300268.).

Pyronaridine-artesunate for treating uncomplicated Plasmodium falciparum malaria

BACKGROUND

The World Health Organization (WHO) recommends artemisinin-based combination therapies (ACTs) to treat uncomplicated Plasmodium falciparum (P falciparum) malaria. Concerns about artemisinin resistance have led to global initiatives to develop new partner drugs to protect artemisinin derivatives in ACT. Pyronaridine-artesunate is a novel ACT.

OBJECTIVES

To evaluate the efficacy of pyronaridine-artesunate compared to alternative ACTs for treating people with uncomplicated P falciparum malaria, and to evaluate the safety of pyronaridine-artesunate and other pyronaridine treatments compared to alternative treatments.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register; Cochrane Central Register of Controlled Trials (CENTRAL), published in the Cochrane Library; MEDLINE; Embase; and LILACS. We also searched ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform Search Portal, and the International Standard Randomized Controlled Trial Number (ISRCTN) registry for ongoing or recently completed trials. The date of the last search was 8 May 2018.

SELECTION CRITERIA

Efficacy analysis: randomized controlled trials (RCTs) of pyronaridine-artesunate for treating uncomplicated P falciparum malaria.Safety analysis: RCTs of pyronaridine-artesunate or pyronaridine for treating P falciparum or P vivax malaria.

DATA COLLECTION AND ANALYSIS

For this update, two review authors independently re-extracted all data and assessed certainty of evidence. We meta-analysed data to calculate risk ratios (RRs) for treatment failures between comparisons, and for safety outcomes between and across comparisons.

MAIN RESULTS

We included 10 relevant studies. Seven studies were co-funded by Shin Poong Pharmaceuticals which manufactures the drug. Three studies were funded by government agencies.For efficacy analysis we identified five RCTs with 5711 participants. This included 4465 participants from 13 sites in Africa, and 1246 participants from five sites in Asia. It included 541 children aged less than five years.For polymerase chain reaction (PCR)-adjusted failures at day 28, pyronaridine-artesunate may have fewer failures compared to artemether-lumefantrine (RR 0.59, 95% confidence interval (CI) 0.26 to 1.31; 4 RCTs, 3068 participants, low-certainty evidence), artesunate-amodiaquine (RR 0.55, 95% CI 0.11 to 2.77; 1 RCT, 1245 participants, low-certainty evidence), and mefloquine plus artesunate (RR 0.37, 95% CI 0.13 to 1.05; 1 RCT, 1117 participants, low-certainty evidence).For unadjusted failures at day 28, pyronaridine-artesunate may have fewer failures compared to artemether-lumefantrine (RR 0.27, 95% CI 0.13 to 0.58; 4 RCTs, 3149 participants, low-certainty evidence), and probably has fewer failures compared to artesunate-amodiaquine (RR 0.49, 95% CI 0.30 to 0.81; 1 RCT, 1257 participants, moderate-certainty evidence) and mefloquine plus artesunate (RR 0.36, 95% CI 0.17 to 0.78; 1 RCT, 1120 participants, moderate-certainty evidence).For PCR-adjusted failures at day 42, pyronaridine-artesunate may make little or no difference compared to artemether-lumefantrine (RR 0.86, 95% CI 0.49 to 1.51; 4 RCTs, 2575 participants, low-certainty evidence) and artesunate-amodiaquine (RR 0.98, 95% CI 0.20 to 4.83; 1 RCT, 1091 participants, low-certainty evidence), but may have higher failures than mefloquine plus artesunate (RR 1.80, 95% CI 0.90 to 3.57; 1 RCT, 1037 participants, low-certainty evidence). Overall, pyronaridine-artesunate had a PCR-adjusted treatment failure rate of less than 5%.For unadjusted failures at day 42, pyronaridine-artesunate may have fewer failures compared to artemether-lumefantrine (RR 0.61, 95% CI 0.46 to 0.82; 4 RCTs, 3080 participants, low-certainty evidence), may make little or no difference compared to mefloquine plus artesunate (RR 0.84, 95% CI 0.54 to 1.31; 1 RCT, 1059 participants, low-certainty evidence), and probably makes little or no difference compared to artesunate-amodiaquine (RR 0.98, 95% CI 0.78 to 1.23; 1 RCT, 1235 participants, moderate-certainty evidence).For the safety analysis of severe adverse events and liver function, we identified eight RCTs with 6614 participants comparing pyronaridine-artesunate to other antimalarials, four of which were not in the previous version of this review. A further two RCTs, comparing pyronaridine alone to other treatments, contributed to the synthesis of all adverse events.Raised alanine aminotransferase (ALT) greater than five times the upper limit of normal (> 5 x ULN) is more frequent with pyronaridine-artesunate compared to other antimalarials (RR 3.34, 95% CI 1.63 to 6.84; 8 RCTS, 6581 participants, high-certainty evidence). There is probably little or no difference for raised bilirubin > 2.5 x ULN between pyronaridine-artesunate and other antimalarials (RR 1.03, 95% CI 0.49 to 2.18; 7 RCTs, 6384 participants, moderate-certainty evidence). There was one reported case in which raised ALT occurred with raised bilirubin, meeting criteria for moderate drug-induced liver injury. No study reported severe drug-induced liver injury. Electrocardiograph (ECG) abnormalities were less common with pyronaridine-artesunate compared to other antimalarials. We identified no other safety concerns.

AUTHORS' CONCLUSIONS

Pyronaridine-artesunate was efficacious against uncomplicated P falciparum malaria, achieved a PCR-adjusted treatment failure rate of less than 5% at days 28 and 42, and may be at least as good as, or better than other marketed ACTs.Pyronaridine-artesunate increases the risk of episodes of raised ALT > 5 x ULN. This meets criteria for mild drug-induced liver injury. On one instance this was linked to raised bilirubin, indicating moderate drug-induced liver injury. No episodes of severe drug-induced liver injury were reported. The findings of this review cannot fully inform a risk-benefit assessment for an unselected population. Readers should remain aware of this uncertainty when considering use of pyronaridine-artesunate in patients with known or suspected pre-existing liver dysfunction, and when co-administering with other medications which may cause liver dysfunction.

Pyronaridine-artesunate and artemether-lumefantrine for the treatment of uncomplicated Plasmodium falciparum malaria in Kenyan children: a randomized controlled non-inferiority trial

Background

Pyronaridine–artesunate is a novel artemisinin-based combination therapy. The efficacy and safety of pyronaridine–artesunate were compared with artemether–lumefantrine for the treatment of uncomplicated Plasmodium falciparum malaria in children.

Methods

This phase III open-label randomized controlled non-inferiority trial was conducted in Western Kenya. Children aged 6 months to ≤ 12 years with a bodyweight > 5 kg and microscopically confirmed P. falciparum malaria were randomly assigned in a 1:1 ratio to orally receive pyronaridine–artesunate or artemether–lumefantrine, dosed according to bodyweight, for 3 days.

Results

Of 197 participants, 101 received pyronaridine–artesunate and 96 received artemether–lumefantrine. The day-28 adequate clinical and parasitological response in the per-protocol population, PCR-corrected for reinfections, was 98.9% (93/94, 95% CI 94.2–99.8) for pyronaridine–artesunate and 96.4% (81/84, 95% CI 90.0–98.8) for artemether–lumefantrine. Pyronaridine–artesunate was found to be non-inferior to artemether–lumefantrine: the treatment difference was 2.5% (95% CI − 2.8 to 9.0). Adverse events occurred in 41.6% (42/101) and 34.4% (33/96) of patients in the pyronaridine–artesunate group and the artemether–lumefantrine group, respectively. No participants were found to have alanine or aspartate aminotransferase levels > 3 times the upper limit of normal.

Conclusions

Pyronaridine–artesunate was well tolerated, efficacious and non-inferior to artemether–lumefantrine for the treatment of uncomplicated P. falciparum malaria in Kenyan children. Results are in line with previous reports and inclusion of pyronaridine–artesunate in paediatric malaria treatment programmes should be considered.

This study is registered at clinicaltrials.gov under NCT02411994. Registration date: 8 April 2015. https://clinicaltrials.gov/ct2/show/NCT02411994?term=pyronaridine–artesunate&cond=Malaria&cntry=KE&rank=1

Electronic supplementary material

The online version of this article (10.1186/s12936-018-2340-3) contains supplementary material, which is available to authorized users.

In Vitro Sensitivity of Pyronaridine in Thai Isolates of Plasmodium falciparum

Pyronaridine, a Mannich base antimalarial agent with a high activity against chloroquine-resistant Plasmodium falciparum, has been combined with artesunate as a new artemisinin based combination therapy (ACT). Pyronaridine-artesunate combination could be one of the choices for the treatment of uncomplicated falciparum malaria in multidrug-resistant areas including Thailand. The aim of this study was to determine in vitro sensitivity and cross-resistance pattern of pyronaridine in Thai isolates of P. falciparum. In addition, the influence of resistant genes concerning in vitro pyronaridine sensitivity was determined. The mean pyronaridine 50% inhibitory concentration (IC₅₀) of 118 parasite isolates was 5.6 ± 3.1 nM (range = 0.2-15.4 nM) with a significant positive correlation with artesunate IC₅₀ (r = 0.246, P = 0.008) and amodiaquine IC₅₀ (r = 0.220, P = 0.042) and a significant negative correlation with quinine IC₅₀ (r = -0.185, P = 0.047). Parasites containing the pfmdr1 86Y allele exhibited significantly reduced pyronaridine sensitivity compared with those with the pfmdr1 N86 allele (7.6 ± 3.3 nM and 5.4 ± 3.0 nM, respectively, P = 0.032, independent t test); however, the difference may not be clinically relevant. Pyronaridine-artesunate could be the candidate ACT to treat multidrug-resistant falciparum malaria in Thailand with careful monitoring.

Malaria medicines to address drug resistance and support malaria elimination efforts

INTRODUCTION

Antimalarial drugs are essential weapons to fight malaria and have been used effectively since the 17^th century. However, P.falciparum resistance has been reported to almost all available antimalarial drugs, including artemisinin derivatives, raising concerns that this could jeopardize malaria elimination. Areas covered: In this article, we present a historical perspective of antimalarial drug resistance, review current evidence of resistance to available antimalarial drugs and discuss possible mitigating strategies to address this challenge. Expert commentary: The historical approach to drug resistance has been to change the national treatment policy to an alternative treatment. However, alternatives to artemisinin-based combination treatment are currently extremely limited. Innovative approaches utilizing available schizonticidal drugs such as triple combination therapies or multiple first line treatments could delay the emergence and spread of drug resistance. Transmission blocking drugs like primaquine may play a key role if given to a substantial proportion of malaria infected persons. Deploying antimalarial medicines in mass drug administration or mass screening and treatment campaigns could also contribute to containment efforts by eliminating resistant parasites in some settings. Ultimately, response to drug resistance should also include further investment in the development of new antimalarial drugs.

Quantification of the antimalarial drug pyronaridine in whole blood using LC-MS/MS - Increased sensitivity resulting from reduced non-specific binding

•

Sensitive and accurate method suitable for high-throughput routine analysis of pyronaridine in whole blood.

•

Validated according to US FDA bioanalytical validation guidelines.

•

Described impact on freeze and thaw stability using different anticoagulants.

•

Described adsorption and carry-over issues and how to overcome them.

Malaria is one of the most important parasitic diseases of man. The development of drug resistance in malaria parasites is an inevitable consequence of their widespread and often unregulated use. There is an urgent need for new and effective drugs. Pyronaridine is a known antimalarial drug that has received renewed interest as a partner drug in artemisinin-based combination therapy. To study its pharmacokinetic properties, particularly in field settings, it is necessary to develop and validate a robust, highly sensitive and accurate bioanalytical method for drug measurements in biological samples. We have developed a sensitive quantification method that covers a wide range of clinically relevant concentrations (1.5 ng/mL to 882 ng/mL) using a relatively low volume sample of 100 μL of whole blood. Total run time is 5 min and precision is within ±15% at all concentration levels. Pyronaridine was extracted on a weak cation exchange solid-phase column (SPE) and separated on a HALO RP amide fused-core column using a gradient mobile phase of acetonitrile–ammonium formate and acetonitrile-methanol. Detection was performed using electrospray ionization and tandem mass spectrometry (positive ion mode with selected reaction monitoring). The developed method is suitable for implementation in high-throughput routine drug analysis, and was used to quantify pyronaridine accurately for up to 42 days after a single oral dose in a drug-drug interaction study in healthy volunteers.

Plasmodium falciparum Resistance to Artemisinin Derivatives and Piperaquine: A Major Challenge for Malaria Elimination in Cambodia

Artemisinin-based combination therapies (ACTs) are the cornerstone of current strategies for fighting malaria. Over the last decade, ACTs have played a major role in decreasing malaria burden. However, this progress is being jeopardized by the emergence of artemisinin-resistant Plasmodium falciparum parasites. Artemisinin resistance was first detected in western Cambodia in 2008 and has since been observed in neighboring countries in southeast Asia. The problem of antimalarial drug resistance has recently worsened in Cambodia, with reports of parasites resistant to piperaquine, the latest generation of partner drug used in combination with dihydroartemisinin, leading to worrying rates of clinical treatment failure. The monitoring and the comprehension of both types of resistance are crucial to prevent the spread of multidrug-resistant parasites outside southeast Asia, and particularly to Africa, where the public health consequences would be catastrophic. To this end, new tools are required for studying the biological and molecular mechanisms underlying resistance to antimalarial drugs and for monitoring the geographic distribution of the resistant parasites. In this review, we detail the major advances in our understanding of resistance to artemisinin and piperaquine and define the challenges that the malaria community will have to face in the coming years.

Efficacy and Safety of Pyronaridine-Artesunate for Treatment of Uncomplicated Plasmodium falciparum Malaria in Western Cambodia

Pyronaridine-artesunate efficacy for the treatment of uncomplicated Plasmodium falciparum malaria was assessed in an area of artemisinin resistance in western Cambodia. This nonrandomized, single-arm, observational study was conducted between 2014 and 2015. Eligible patients were adults or children with microscopically confirmed P. falciparum infection and fever. Patients received pyronaridine-artesunate once daily for 3 days, dosed according to body weight. The primary outcome was an adequate clinical and parasitological response (ACPR) on day 42, estimated by using Kaplan-Meier analysis, PCR adjusted to exclude reinfection. One hundred twenty-three patients were enrolled. Day 42 PCR-crude ACPRs were 87.2% (95% confidence interval [CI], 79.7 to 92.6%) for the overall study, 89.8% (95% CI, 78.8 to 95.3%) for Pursat, and 82.1% (95% CI, 68.4 to 90.2%) for Pailin. Day 42 PCR-adjusted ACPRs were 87.9% (95% CI, 80.6 to 93.2%) for the overall study, 89.8% (95% CI, 78.8 to 95.3%) for Pursat, and 84.0% (95% CI, 70.6 to 91.7%) for Pailin (P = 0.353 by a log rank test). Day 28 PCR-crude and -adjusted ACPRs were 93.2% (95% CI, 82.9 to 97.4%) and 88.1% (95% CI, 75.3 to 94.5%) for Pursat and Pailin, respectively. A significantly lower proportion of patients achieved day 3 parasite clearance in Pailin (56.4% [95% CI, 43.9 to 69.6%]) than in Pursat (86.7% [95% CI, 76.8 to 93.8%]; P = 0.0019). Fever clearance was also extended at Pailin versus Pursat (P < 0.0001). Most patients (95.9% [116/121]) harbored P. falciparum kelch13 C580Y mutant parasites. Pyronaridine-artesunate was well tolerated; mild increases in hepatic transaminase levels were consistent with data from previous reports. Pyronaridine-artesunate efficacy was below the World Health Organization-recommended threshold at day 42 for medicines with a long half-life (90%) for first-line treatment of P. falciparum malaria in western Cambodia despite high efficacy elsewhere in Asia and Africa. (This study has been registered at ClinicalTrials.gov under registration number NCT02389439.).

Single dose treatment of malaria - current status and perspectives

INTRODUCTION

Despite increased international efforts for control and ultimate elimination, malaria remains a major health problem. Currently, artemisinin-based combination therapies are the treatment of choice for uncomplicated malaria exhibiting high efficacy in clinical trial settings in sub-Saharan Africa. However, their administration over a three-day period is associated with important problems of treatment adherence resulting in markedly reduced effectiveness of currently recommended antimalarials under real world settings.

AREAS COVERED

Antimalarial drug candidates and antimalarial drug combinations currently under advanced clinical development for the indication as single dose antimalarial therapy. Expert commentary: Several new drug candidates and combinations are currently undergoing pivotal proof-of-concept studies or clinical development programmes. The development of a single dose combination therapy would constitute a breakthrough in the control of malaria. Such an innovative treatment approach would simultaneously close the effectiveness gap of current three-day therapies and revolutionize population based interventions in the context of malaria elimination campaigns.

Pyrrolidine-Acridine hybrid in Artemisinin-based combination: a pharmacodynamic study

Aiming to develop new artemisinin-based combination therapy (ACT) for malaria, antimalarial effect of a new series of pyrrolidine-acridine hybrid in combination with artemisinin derivatives was investigated. Synthesis, antimalarial and cytotoxic evaluation of a series of hybrid of 2-(3-(substitutedbenzyl)pyrrolidin-1-yl)alkanamines and acridine were performed and mode of action of the lead compound was investigated. In vivo pharmacodynamic properties (parasite clearance time, parasite reduction ratio, dose and regimen determination) against multidrug resistant (MDR) rodent malaria parasite and toxicological parameters (median lethal dose, liver function test, kidney function test) were also investigated. 6-Chloro-N-(4-(3-(3,4-dimethoxybenzyl)pyrrolidin-1-yl)butyl)-2-methoxyacridin-9-amine (15c) has shown a dose dependent haem bio-mineralization inhibition and was found to be the most effective and safe compound against MDR malaria parasite in Swiss mice model. It displayed best antimalarial potential with artemether (AM) in vitro as well as in vivo. The combination also showed favourable pharmacodynamic properties and therapeutic response in mice with established MDR malaria infection and all mice were cured at the determined doses. The combination did not show toxicity at the doses administered to the Swiss mice. Taken together, our findings suggest that compound 15c is a potential partner with AM for the ACT and could be explored for further development.

Population Pharmacokinetics of Pyronaridine in Pediatric Malaria Patients

Pyramax is a pyronaridine (PYR)-artesunate (PA) combination for the treatment of uncomplicated malaria in adult and pediatric patients. A granule formulation of this combination is being developed for treatment of uncomplicated P. falciparum and P. vivax malaria in pediatric patients. The aims of this study were to describe the pharmacokinetics of PYR using a total of 1,085 blood PYR concentrations available from 349 malaria patients younger than 16 years of age with mild to moderate uncomplicated malaria and to confirm the dosing regimen for the pediatric granule formulation. Nonlinear mixed-effects modeling using NONMEM software was used to obtain the pharmacokinetic and inter- and intraindividual variability parameter estimates. The population pharmacokinetics of PYR were described by a two-compartment model with first-order absorption and elimination. Allometric scaling was implemented to address the effect of body weight on clearance and volume parameters. The final parameter estimates of PYR apparent clearance (CL/F), central volume of distribution (V₂/F), peripheral volume of distribution (V₃/F), intercompartmental clearance (Q/F), and absorption rate constant (K_a) were 377 liters/day, 2,230 liters, 3,230 liters, 804 liters/day and 17.9 day⁻¹, respectively. Covariate model building conducted using forward addition (P < 0.05) followed by backward elimination (P < 0.001) yielded two significant covariate-parameter relationships, i.e., age on V₂/F and formulation on K_a. Evaluation of bootstrapping, visual predictive check, and condition number indicated that the final model displayed satisfactory robustness, predictive power, and stability. Simulations of PYR concentration-time profiles generated from the final model show similar exposures across pediatric weight ranges, supporting the proposed labeling for weight-based dosing of Pyramax granules. (These studies have been registered at ClinicalTrials.gov under registration no. NCT00331136 [phase II study] and NCT00541385, NCT00403260, NCT00422084, and NCT00440999 [phase III studies]. The most recent phase III study was registered at pactr.org under registration no. PACTR201105000286876.)

Safety and efficacy of re-treatments with pyronaridine-artesunate in African patients with malaria: a substudy of the WANECAM randomised trial

BACKGROUND

Sparse data on the safety of pyronaridine-artesunate after repeated treatment of malaria episodes restrict its clinical use. We therefore compared the safety of pyronaridine-artesunate after treatment of the first episode of malaria versus re-treatment in a substudy analysis.

METHODS

This planned substudy analysis of the randomised, open-label West African Network for Clinical Trials of Antimalarial Drugs (WANECAM) phase 3b/4 trial was done at six health facilities in Mali, Burkina Faso, and Guinea in patients (aged ≥6 months and bodyweight ≥5 kg) with uncomplicated microscopically confirmed Plasmodium spp malaria (parasite density <200 000 per μL blood) and fever or history of fever. The primary safety endpoint was incidence of hepatotoxicity: alanine aminotransferase of greater than five times the upper limit of normal (ULN) or Hy's criteria (alanine aminotransferase or aspartate aminotransferase greater than three times the ULN and total bilirubin more than twice the ULN) after treatment of the first episode of malaria and re-treatment (≥28 days after first treatment) with pyronaridine-artesunate. Pyronaridine-artesunate efficacy was compared with artemether-lumefantrine with the adequate clinical and parasitological response (ACPR) in an intention-to-treat analysis. WANECAM is registered with PACTR.org, number PACTR201105000286876.

FINDINGS

Following first treatment, 13 (1%) of 996 patients had hepatotoxicity (including one [<1%] possible Hy's law case) versus two (1%) of 311 patients on re-treatment (neither a Hy's law case). No evidence was found that pyronaridine-artesunate re-treatment increased safety risk based on laboratory values, reported adverse event frequencies, or electrocardiograph findings. For all first treatment or re-treatment episodes, pyronaridine-artesunate (n=673) day 28 crude ACPR was 92·7% (95% CI 91·0-94·3) versus 80·4% (77·8-83·0) for artemether-lumefantrine (n=671). After exclusion of patients with PCR-confirmed new infections, ACPR was similar on treatment and re-treatment and greater than 95% at day 28 and greater than 91% at day 42 in both treatment groups.

INTERPRETATION

The findings that pyronaridine-artesunate safety and efficacy were similar on first malaria treatment versus re-treatment of subsequent episodes lend support for the wider access to pyronaridine-artesunate as an alternative artemisinin-based combination treatment for malaria in sub-Saharan Africa.

FUNDING

European and Developing Countries Clinical Trial Partnership, Medicines for Malaria Venture (Geneva, Switzerland), UK Medical Research Council, Swedish International Development Cooperation Agency, German Ministry for Education and Research, University Claude Bernard (Lyon, France), Malaria Research and Training Centre (Bamako, Mali), Centre National de Recherche et de Formation sur le Paludisme (Burkina Faso), Institut de Recherche en Sciences de la Santé (Bobo-Dioulasso, Burkina Faso), and Centre National de Formation et de Recherche en Santé Rurale (Republic of Guinea).

Tailoring a Pediatric Formulation of Artemether-Lumefantrine for Treatment of Plasmodium falciparum Malaria

Specially created pediatric formulations have the potential to improve the acceptability, effectiveness, and accuracy of dosing of artemisinin-based combination therapy (ACT) in young children, a patient group that is inherently vulnerable to malaria. Artemether-lumefantrine (AL) Dispersible is a pediatric formulation of AL that is specifically tailored for the treatment of children with uncomplicated Plasmodium falciparum malaria, offering benefits relating to efficacy, convenience and acceptance, accuracy of dosing, safety, sterility, stability, and a pharmacokinetic profile and bioequivalence similar to those of crushed and intact AL tablets. However, despite being the first pediatric antimalarial to meet World Health Organization (WHO) specifications for use in infants and children who are ≥5 kg in body weight and its inclusion in WHO Guidelines, there are few publications that focus on AL Dispersible. Based on a systematic review of the recent literature, this paper provides a comprehensive overview of the clinical experience with AL Dispersible to date. A randomized, phase 3 study that compared the efficacy and safety of AL Dispersible to those of crushed AL tablets in 899 African children reported high PCR-corrected cure rates at day 28 (97.8% and 98.5% for AL Dispersible and crushed tablets, respectively), and the results of several subanalyses of these data indicate that this activity is observed regardless of patient weight, food intake, and maximum plasma concentrations of artemether or its active metabolite, dihydroartemisinin. These and other clinical data support the continued use of pediatric antimalarial formulations in all children <5 years of age with uncomplicated malaria when accompanied by continued monitoring for the emergence of resistance.

Haemolysis associated with the treatment of malaria with artemisinin derivatives: a systematic review of current evidence

BACKGROUND

Artemisinin derivatives are the mainstay of antimalarial treatment, both for uncomplicated malaria and for severe disease. Artemisinins are known for their rapid onset of action, good tolerability, and safety. However, besides the sporadic but worrying reports of delayed parasite clearance after treatment with artemisinins, there have been an increasing number of reports of acute haemolytic anaemia following their use and the safety of this class of antimalarials is being questioned.

METHODS

In this systematic review, all reports of patients experiencing haemolysis following the use of artemisinins for the treatment of malaria were identified and collated into an electronic database. Summary statistics were calculated to characterize the epidemiology and clinical features of this safety concern related to artemisinin derivatives.

RESULTS

A total of 37 patients were identified suffering from haemolysis following the treatment of severe malaria with artemisinin derivatives. Thirty-one cases had received intravenous artesunate, while the remaining cases were attributed to other parenteral or oral regimens of artemisinin derivatives. The majority of patients were returning travellers (n=30), and six clinical cases had been reported in paediatric patients. The median onset of haemolysis was 15 (interquartile range (IQR) 13-15) days after the initiation of treatment for the 'delayed-onset' pattern and 17 (IQR 13-22) days for the 'persistent' haemolysis pattern. The median reduction in haemoglobin due to haemolysis was 6 g/dl (IQR 4-8 g/dl). The estimated proportion of patients suffering from severe malaria experiencing haemolysis after treatment with artemisinin derivatives was 13% (95% confidence interval 9-18%), and 73% of these (i.e., 9% of the total population) required blood transfusions. No fatal outcome has been reported in the literature to date.

CONCLUSIONS

Haemolysis is commonly associated with the class of artemisinin drugs when used for the treatment of severe malaria. Potential causes of this safety issue are discussed. Although no deaths attributed to haemolysis have been reported so far, this safety issue may lead to life-threatening anaemia and is particularly worrying for regions where safe blood products are not readily available.

Nanomedicines in the future of pediatric therapy

Nanotechnology has become a key tool to overcome the main (bio)pharmaceutical drawbacks of drugs and to enable their passive or active targeting to specific cells and tissues. Pediatric therapies usually rely on the previous clinical experience in adults. However, there exists scientific evidence that drug pharmacokinetics and pharmacodynamics in children differ from those in adults. For example, the interaction of specific drugs with their target receptors undergoes changes over the maturation of the different organs and systems. A similar phenomenon is observed for toxicity and adverse effects. Thus, it is clear that the treatment of disease in children cannot be simplified to the direct adjustment of the dose to the body weight/surface. In this context, the implementation of innovative technologies (e.g., nanotechnology) in the pediatric population becomes extremely challenging. The present article overviews the different attempts to use nanotechnology to treat diseases in the pediatric population. Due to the relevance, though limited available literature on the matter, we initially describe from preliminary in vitro studies to preclinical and clinical trials aiming to treat pediatric infectious diseases and pediatric solid tumors by means of nanotechnology. Then, the perspectives of pediatric nanomedicine are discussed.

Artesunate plus pyronaridine for treating uncomplicated Plasmodium falciparum malaria

BACKGROUND

The World Health Organization (WHO) recommends that people with uncomplicated Plasmodium falciparum malaria are treated using Artemisinin-based Combination Therapy (ACT). ACT combines three-days of a short-acting artemisinin derivative with a longer-acting antimalarial which has a different mode of action. Pyronaridine has been reported as an effective antimalarial over two decades of use in parts of Asia, and is currently being evaluated as a partner drug for artesunate.

OBJECTIVES

To evaluate the efficacy and safety of artesunate-pyronaridine compared to alternative ACTs for treating people with uncomplicated P. falciparum malaria.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register; Cochrane Central Register of Controlled Trials (CENTRAL), published in The Cochrane Library; MEDLINE; EMBASE; LILACS; ClinicalTrials.gov; the metaRegister of Controlled Trials (mRCT); and the WHO International Clinical Trials Search Portal up to 16 January 2014. We searched reference lists and conference abstracts, and contacted experts for information about ongoing and unpublished trials.

SELECTION CRITERIA

Randomized controlled trials of artesunate-pyronaridine versus other ACTs in adults and children with uncomplicated P. falciparum malaria.For the safety analysis, we also included adverse events data from trials comparing any treatment regimen containing pyronaridine with regimens not containing pyronaridine.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial eligibility and risk of bias, and extracted data. We combined dichotomous data using risk ratios (RR) and continuous data using mean differences (MD), and presented all results with a 95% confidence interval (CI). We used the GRADE approach to assess the quality of evidence.

MAIN RESULTS

We included six randomized controlled trials enrolling 3718 children and adults. Artesunate-pyronaridine versus artemether-lumefantrineIn two multicentre trials, enrolling mainly older children and adults from west and south-central Africa, both artesunate-pyronaridine and artemether-lumefantrine had fewer than 5% PCR adjusted treatment failures during 42 days of follow-up, with no differences between groups (two trials, 1472 participants, low quality evidence). There were fewer new infections during the first 28 days in those given artesunate-pyronaridine (PCR-unadjusted treatment failure: RR 0.60, 95% CI 0.40 to 0.90, two trials, 1720 participants, moderate quality evidence), but no difference was detected over the whole 42 day follow-up (two trials, 1691 participants, moderate quality evidence). Artesunate-pyronaridine versus artesunate plus mefloquineIn one multicentre trial, enrolling mainly older children and adults from South East Asia, both artesunate-pyronaridine and artesunate plus mefloquine had fewer than 5% PCR adjusted treatment failures during 28 days follow-up (one trial, 1187 participants, moderate quality evidence). PCR-adjusted treatment failures were 6% by day 42 for these treated with artesunate-pyronaridine, and 4% for those with artesunate-mefloquine (RR 1.64, 95% CI 0.89 to 3.00, one trial, 1116 participants, low quality evidence). Again, there were fewer new infections during the first 28 days in those given artesunate-pyronaridine (PCR-unadjusted treatment failure: RR 0.35, 95% CI 0.17 to 0.73, one trial, 1720 participants, moderate quality evidence), but no differences were detected over the whole 42 days (one trial, 1146 participants, low quality evidence). Adverse effectsSerious adverse events were uncommon in these trials, with no difference detected between artesunate-pyronaridine and comparator ACTs. The analysis of liver function tests showed biochemical elevation were four times more frequent with artesunate-pyronaridine than with the other antimalarials (RR 4.17, 95% CI 1.38 to 12.62, four trials, 3523 participants, moderate quality evidence).

AUTHORS' CONCLUSIONS

Artesunate-pyronaridine performed well in these trials compared to artemether-lumefantrine and artesunate plus mefloquine, with PCR-adjusted treatment failure at day 28 below the 5% standard set by the WHO. Further efficacy and safety studies in African and Asian children are required to clarify whether this combination is an option for first-line treatment.

Effects of body size and gender on the population pharmacokinetics of artesunate and its active metabolite dihydroartemisinin in pediatric malaria patients

Despite the important role of the antimalarial artesunate and its active metabolite dihydroartemisinin (DHA) in malaria treatment efforts, there are limited data on the pharmacokinetics of these agents in pediatric patients. This study evaluated the effects of body size and gender on the pharmacokinetics of artesunate-DHA using data from pediatric and adult malaria patients. Nonlinear mixed-effects modeling was used to obtain a base model consisting of first-order artesunate absorption and one-compartment models for artesunate and for DHA. Various methods of incorporating effects of body size descriptors on clearance and volume parameters were tested. An allometric scaling model for weight and a linear body surface area (BSA) model were deemed optimal. The apparent clearance and volume of distribution of DHA obtained with the allometric scaling model, normalized to a 38-kg patient, were 63.5 liters/h and 65.1 liters, respectively. Estimates for the linear BSA model were similar. The 95% confidence intervals for the estimated gender effects on clearance and volume parameters for artesunate fell outside the predefined no-relevant-clinical-effect interval of 0.75 to 1.25. However, the effect of gender on apparent DHA clearance was almost entirely contained within this interval, suggesting a lack of an influence of gender on this parameter. Overall, the pharmacokinetics of artesunate and DHA following oral artesunate administration can be described for pediatric patients using either an allometric scaling or linear BSA model. Both models predict that, for a given artesunate dose in mg/kg of body weight, younger children are expected to have lower DHA exposure than older children or adults.

Safety and efficacy of pyronaridine-artesunate in uncomplicated acute malaria: an integrated analysis of individual patient data from six randomized clinical trials

BACKGROUND

Pyronaridine-artesunate (PA) is indicated for the treatment of acute uncomplicated Plasmodium falciparum and Plasmodium vivax malaria.

METHODS

Individual patient data on safety outcomes were integrated from six randomized clinical trials conducted in Africa and Asia in patients with microscopically confirmed P. falciparum (five studies) or P. vivax (one study) malaria. Efficacy against P. falciparum was evaluated across three Phase III clinical trials.

RESULTS

The safety population included 2,815 patients randomized to PA, 1,254 to comparators: mefloquine + artesunate (MQ + AS), artemether-lumefantrine (AL), or chloroquine. All treatments were generally well tolerated. Adverse events occurred in 57.2% (1,611/2,815) of patients with PA versus 51.5% (646/1,254) for comparators, most commonly (PA; comparators): headache (10.6%; 9.9%), cough (5.9%; 5.6%) and anaemia (4.5%; 2.9%). Serious averse events were uncommon for all treatments (0-0.7%). Transient increases in alanine aminotransferase and aspartate aminotransferase were observed with PA but did not lead to any clinical sequelae. For P. falciparum malaria, day-28 PCR-corrected adequate clinical and parasitological response with PA was 93.6% ([1,921/2,052] 95% CI 92.6, 94.7) in the intent-to-treat population and 98.5% ([1,852/1,880] 95% CI 98.0, 99.1) in the per-protocol population. Median parasite clearance time was 24.1 h with PA, 31.9 h with MQ + AS, and 24.0 h with AL. Median fever clearance time was 15.5 h with PA, 15.8 h with MQ + AS, and 14.0 h with AL. By day 42, P. falciparum gametocytes had declined to near zero for all treatments.

CONCLUSIONS

Pyronaridine-artesunate was well tolerated with no safety concerns with the exception of mostly mild transient rises in transaminases. Efficacy was high and met the requirements for use as first-line therapy. Pyronaridine-artesunate should be considered for inclusion in malaria treatment programmes.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT00331136; NCT00403260; NCT00422084; NCT00440999; NCT00541385; NCT01594931.

Pyronaridine-artesunate granules versus artemether-lumefantrine crushed tablets in children with Plasmodium falciparum malaria: a randomized controlled trial

Background

Children are most vulnerable to malaria. A pyronaridine-artesunate pediatric granule formulation is being developed for the treatment of uncomplicated Plasmodium falciparum malaria.

Methods

This phase III, multi-center, comparative, open-label, parallel-group, controlled clinical trial included patients aged ≤12 years, bodyweight ≥5 to <25 kg, with a reported history of fever at inclusion or in the previous 24 h and microscopically-confirmed uncomplicated P. falciparum malaria. Patients were randomized (2:1) to pyronaridine-artesunate granules (60/20 mg) once daily or artemether-lumefantrine crushed tablets (20/120 mg) twice daily, both dosed by bodyweight, orally (liquid suspension) for three days.

Results

Of 535 patients randomized, 355 received pyronaridine-artesunate and 180 received artemether-lumefantrine. Day-28 adequate clinical and parasitological response (ACPR), corrected for re-infection using polymerase chain reaction (PCR) genotyping (per-protocol population) was 97.1% (329/339; 95% CI 94.6, 98.6) for pyronaridine-artesunate; 98.8% (165/167; 95% CI 95.7, 99.9) for artemether-lumefantrine. The primary endpoint was achieved: pyronaridine-artesunate PCR-corrected day-28 ACPR was statistically significantly >90% (P < .0001). Pyronaridine-artesunate was non-inferior to artemether-lumefantrine: treatment difference -1.8% (95% CI -4.3 to 1.6). The incidence of drug-related adverse events was 37.2% (132/355) with pyronaridine-artesunate, 44.4% (80/180) with artemether-lumefantrine. Clinical biochemistry results showed similar mean changes versus baseline in the two treatment groups. From day 3 until study completion, one patient in each treatment group had peak alanine aminotransferase (ALT) >3 times the upper limit of normal (ULN) and peak total bilirubin >2xULN (i.e. within the Hy’s law definition).

Conclusions

The pyronaridine-artesunate pediatric granule formulation was efficacious and was non-inferior to artemether-lumefantrine. The adverse event profile was similar for the two comparators. Pyronaridine-artesunate should be considered for inclusion in paediatric malaria treatment programmes.

Trial registration

ClinicalTrials.gov: identifier NCT00541385

Repeated artemisinin-based combination therapies in a malaria hyperendemic area of Mali: efficacy, safety, and public health impact

Artemisinin-based combination therapies (ACTs) are the first-line treatment of uncomplicated malaria. The public health benefit and safety of repeated administration of a given ACT are poorly studied. We conducted a randomized trial comparing artemether-lumefantrine, artesunate plus amodiaquine (AS+AQ) and artesunate plus sulfadoxine-pyrimethamine (AS+SP) in patients 6 months of age and older with uncomplicated malaria in Mali from July 2005 to July 2007. The patient received the same initial treatment of each subsequent uncomplicated malaria episode except for treatment failures where quinine was used. Overall, 780 patients were included. Patients in the AS+AQ and AS+SP arms had significantly less risk of having malaria episodes; risk ratio (RR) = 0.84 (P = 0.002) and RR = 0.80 (P = 0.001), respectively. The treatment efficacy was similar and above 95% in all arms. Although all drugs were highly efficacious and well tolerated, AS+AQ and AS+SP were associated with less episodes of malaria.

The global pipeline of new medicines for the control and elimination of malaria

Over the past decade, there has been a transformation in the portfolio of medicines to combat malaria. New fixed-dose artemisinin combination therapy is available, with four different types having received approval from Stringent Regulatory Authorities or the World Health Organization (WHO). However, there is still scope for improvement. The Malaria Eradication Research agenda identified several gaps in the current portfolio. Simpler regimens, such as a single-dose cure are needed, compared with the current three-day treatment. In addition, new medicines that prevent transmission and also relapse are needed, but with better safety profiles than current medicines. There is also a big opportunity for new medicines to prevent reinfection and to provide chemoprotection. This study reviews the global portfolio of new medicines in development against malaria, as of the summer of 2012. Cell-based phenotypic screening, and 'fast followers' of clinically validated classes, mean that there are now many new classes of molecules starting in clinical development, especially for the blood stages of malaria. There remain significant gaps for medicines blocking transmission, preventing relapse, and long-duration molecules for chemoprotection. The nascent pipeline of new medicines is significantly stronger than five years ago. However, there are still risks ahead in clinical development and sustainable funding of clinical studies is vital if this early promise is going to be delivered.

Review of pyronaridine anti-malarial properties and product characteristics

Pyronaridine was synthesized in 1970 at the Institute of Chinese Parasitic Disease and has been used in China for over 30 years for the treatment of malaria. Pyronaridine has high potency against Plasmodium falciparum, including chloroquine-resistant strains. Studies in various animal models have shown pyronaridine to be effective against strains resistant to other anti-malarials, including chloroquine. Resistance to pyronaridine appears to emerge slowly and is further retarded when pyronaridine is used in combination with other anti-malarials, in particular, artesunate. Pyronaridine toxicity is generally less than that of chloroquine, though evidence of embryotoxicity in rodents suggests use with caution in pregnancy. Clinical pharmacokinetic data for pyronaridine indicates an elimination T_1/2 of 13.2 and 9.6 days, respectively, in adults and children with acute uncomplicated falciparum and vivax malaria in artemisinin-combination therapy. Clinical data for mono or combined pyronaridine therapy show excellent anti-malarial effects against P. falciparum and studies of combination therapy also show promise against Plasmodium vivax. Pyronaridine has been developed as a fixed dose combination therapy, in a 3:1 ratio, with artesunate for the treatment of acute uncomplicated P. falciparum malaria and blood stage P. vivax malaria with the name of Pyramax® and has received Positive Opinion by European Medicines Agency under the Article 58 procedure.

Pyronaridine-artesunate versus mefloquine plus artesunate for malaria

BACKGROUND

Pyronaridine-artesunate is an artemisinin-based combination therapy under evaluation for the treatment of Plasmodium falciparum and P. vivax malaria.

METHODS

We conducted a phase 3, open-label, multicenter, noninferiority trial that included 1271 patients between 3 and 60 years of age from Asia (81.3%) or Africa (18.7%) with microscopically confirmed, uncomplicated P. falciparum malaria. Patients underwent randomization for treatment with a fixed-dose combination of 180 mg of pyronaridine and 60 mg of artesunate or with 250 mg of mefloquine plus 100 mg of artesunate. Doses were calculated according to body weight and administered once daily for 3 days.

RESULTS

Pyronaridine-artesunate was noninferior to mefloquine plus artesunate for the primary outcome: adequate clinical and parasitologic response in the per-protocol population on day 28, corrected for reinfection with the use of polymerase-chain-reaction (PCR) genotyping. For this outcome, efficacy in the group receiving pyronaridine-artesunate was 99.2% (743 of 749 patients; 95% confidence interval [CI], 98.3 to 99.7) and that in the group receiving mefloquine plus artesunate was 97.8% (360 of 368 patients; 95% CI, 95.8 to 99.1), with a treatment difference of 1.4 percentage points (95% CI, 0.0 to 3.5; P=0.05). In the intention-to-treat population, efficacy on day 42 in the group receiving pyronaridine-artesunate was 83.1% (705 of 848 patients; 95% CI, 80.4 to 85.6) and that in the group receiving mefloquine plus artesunate was 83.9% (355 of 423 patients; 95% CI, 80.1 to 87.3). In Cambodia, where there were 211 study patients, the median parasite clearance time was prolonged for both treatments: 64 hours versus 16.0 to 38.9 hours in other countries (P<0.001, on the basis of Kaplan-Meier estimates). Kaplan-Meier estimates of the recrudescence rate in the intention-to-treat population in Cambodia until day 42 were higher with pyronaridine-artesunate than with mefloquine plus artesunate (10.2% [95% CI, 5.4 to 18.6] vs. 0%; P=0.04 as calculated with the log-rank test), but similar for the other countries combined (4.7% [95% CI, 3.3 to 6.7] and 2.8% [95% CI, 1.5 to 5.3], respectively; P=0.24). Elevated levels of aminotransferases were observed in those receiving pyronaridine-artesunate. Two patients receiving mefloquine plus artesunate had seizures.

CONCLUSIONS

Fixed-dose pyronaridine-artesunate was efficacious in the treatment of uncomplicated P. falciparum malaria. In Cambodia, extended parasite clearance times were suggestive of in vivo resistance to artemisinin. (Funded by Shin Poong Pharmaceutical Company and the Medicines for Malaria Venture; ClinicalTrials.gov number, NCT00403260.).

Pharmacokinetics of ferroquine, a novel 4-aminoquinoline, in asymptomatic carriers of Plasmodium falciparum infections

Ferroquine (SSR97193), a ferrocene-quinoline conjugate, is a promising novel antimalarial currently undergoing clinical evaluation. This study characterizes its pharmacokinetic properties. Young male African volunteers with asymptomatic Plasmodium falciparum infection were administered a single oral dose (n = 40) or a repeated oral dose (n = 26) given over 3 days of ferroquine in two dose-escalation, double-blind, randomized, placebo-controlled clinical trials. In addition, a food interaction study was performed in a subsample of participants (n = 16). The studies were carried out in Lambaréné, Gabon. After single-dose administration of ferroquine, dose linearity was demonstrated in a dose range of 400 to 1,200 mg for maximum mean blood concentrations ([C(max)] 82 to 270 ng/ml) and in a dose range of 400 to 1,600 mg for overall exposure to ferroquine (area under the concentration-time curve [AUC], 13,100 to 49,200 ng · h/ml). Overall mean estimate for blood apparent terminal half-life of ferroquine was 16 days and 31 days for its active and major metabolite desmethylferroquine (SSR97213). In the 3-day repeated-dose study, C(max) and overall cumulated exposure to ferroquine (AUC(cum)) increased in proportion with the dose from day 1 to day 3 between 400 and 800 mg. No major food effect on ferroquine pharmacokinetics was observed after single administration of 100 mg of ferroquine except for a slight delay of time to maximum blood concentration (t(max)) by approximately 3 h. The pharmacokinetics of ferroquine and its active main metabolite are characterized by sustained levels in blood, and the properties of ferroquine as a partner drug in antimalarial combination therapy should be evaluated.

Ex vivo activity of the ACT new components pyronaridine and piperaquine in comparison with conventional ACT drugs against isolates of Plasmodium falciparum

Background

The aim of the present work was to assess i) ex vivo activity of pyronaridine (PND) and piperaquine (PPQ), as new components of artemisinin-based combination therapy (ACT), to define susceptibility baseline, ii) their activities compared to other partner drugs, namely monodesethylamodiaquine (MDAQ), lumefantrine (LMF), mefloquine (MQ), artesunate (AS) and dihydroartemisinin (DHA) against 181 Plasmodium falciparum isolates from African countries, India and Thailand, and iii) in vitro cross-resistance with other quinoline drugs, chloroquine (CQ) or quinine (QN).

Methods

The susceptibility of the 181 P. falciparum isolates to the nine anti-malarial drugs was assessed using the standard 42-hours ³H-hypoxanthine uptake inhibition method.

Results

The IC₅₀ values for PND ranged from 0.55 to 80.0 nM (geometric mean = 19.9 nM) and from 11.8 to 217.3 nM for PPQ (geometric mean = 66.8 nM). A significant positive correlation was shown between responses to PPQ and PND responses (rho = 0.46) and between PPQ and MDAQ (rho = 0.30). No significant correlation was shown between PPQ IC₅₀ and responses to other anti-malarial drugs. A significant positive correlation was shown between responses to PND and MDAQ (rho = 0.37), PND and LMF (rho = 0.28), PND and QN (rho = 0.24), PND and AS (rho = 0.19), PND and DHA (rho = 0.18) and PND and CQ (rho = 0.16). All these coefficients of correlation are too low to suggest cross-resistance between PPQ or PND and the other drugs.

Conclusions

In this study, the excellent anti-malarial activity of PPQ and PND was confirmed. The absence of cross-resistance with quinolines and artemisinin derivatives is consistent with the efficacy of the combinations of PPQ and DHA or PND and AS in areas where parasites are resistant to conventional anti-malarial drugs.

The activities of current antimalarial drugs on the life cycle stages of Plasmodium: a comparative study with human and rodent parasites

BACKGROUND

Malaria remains a disease of devastating global impact, killing more than 800,000 people every year-the vast majority being children under the age of 5. While effective therapies are available, if malaria is to be eradicated a broader range of small molecule therapeutics that are able to target the liver and the transmissible sexual stages are required. These new medicines are needed both to meet the challenge of malaria eradication and to circumvent resistance.

METHODS AND FINDINGS

Little is known about the wider stage-specific activities of current antimalarials that were primarily designed to alleviate symptoms of malaria in the blood stage. To overcome this critical gap, we developed assays to measure activity of antimalarials against all life stages of malaria parasites, using a diverse set of human and nonhuman parasite species, including male gamete production (exflagellation) in Plasmodium falciparum, ookinete development in P. berghei, oocyst development in P. berghei and P. falciparum, and the liver stage of P. yoelii. We then compared 50 current and experimental antimalarials in these assays. We show that endoperoxides such as OZ439, a stable synthetic molecule currently in clinical phase IIa trials, are strong inhibitors of gametocyte maturation/gamete formation and impact sporogony; lumefantrine impairs development in the vector; and NPC-1161B, a new 8-aminoquinoline, inhibits sporogony.

CONCLUSIONS

These data enable objective comparisons of the strengths and weaknesses of each chemical class at targeting each stage of the lifecycle. Noting that the activities of many compounds lie within achievable blood concentrations, these results offer an invaluable guide to decisions regarding which drugs to combine in the next-generation of antimalarial drugs. This study might reveal the potential of life-cycle-wide analyses of drugs for other pathogens with complex life cycles.

Novel formulation and drug delivery strategies for the treatment of pediatric poverty-related diseases

INTRODUCTION

Due to a lack of approved drugs and formulations, children represent the most vulnerable patients. Magistral, unlicensed formulations obtained by the manipulation of solid forms should undergo clinical evaluation to ensure bioequivalence. The development of new pediatric medicines is complex and faces technological, economic and ethical challenges. This phenomenon has contributed to the emergence of an adult-children gap. To improve the situation, the World Health Organization launched the global campaign 'Make medicines child size' and a number of international initiatives have been established. The situation is more critical in the case of poverty-related diseases (PRDs) that mainly affect poor countries.

AREAS COVERED

This review critically discusses different strategies to develop pediatric formulations and drug delivery systems (DDS) in PRDs and their potential implementation in the current market. Readers will gain an updated perspective on the development of pediatric medicines for the treatment of PRDs and the proximate challenges and opportunities faced to ensure an effective pharmacotherapy.

EXPERT OPINION

There is an urgent need for the development of innovative, scalable and cost-viable formulations to ensure pediatric patients have access to appropriate medications for PRDs. The guidelines of the International Conference on Harmonisation constitute a very good orientation tool, as they emphasize physiological and developmental aspects that need to be considered in pediatric research. It is important to consider cultural, economic and ethical aspects that make developing nations facing PRDs different from the developed world. Thus, the best strategy would probably be to conceive and engage similar initiatives in the developing world, to address unattended therapeutic niches.

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.

The use of paediatric artemisinin combinations in sub-Saharan Africa: a snapshot questionnaire survey of health care personnel

Background

Paediatric drug formulations for artemisinin combination therapy (P-ACT) have been developed over the past few years and have been shown to improve the therapeutic management of young children with uncomplicated falciparum malaria. This process was however not equally paralleled by a timely adoption of P-ACT in national and international treatment recommendations. National malaria programmes in sub-Saharan Africa have not yet widely embraced this new therapeutic tool. To which extent P-ACT is used in the field in sub-Saharan Africa is not known to date.

Methods

This snapshot questionnaire survey aimed to provide an overview on the current routine practices for the availability and use of P-ACT as anti-malarial treatment for young children in sub-Saharan Africa. Health care personnel in seven countries in West-, Central, and East-Africa were invited to answer a structured questionnaire assessing use and availability of P-ACT.

Results

A total of 71 respondents including doctors, nurses and pharmacy personnel responsible for the anti-malarial treatment of young children were interviewed. P-ACT was used by 83% (95% confidence interval: 73-90%; n = 59) as first-line treatment for young children. Use of 15 different P-ACT products was reported among which only two have received WHO prequalification status and approval by a stringent registration authority. Use of a specific P-ACT product was not linked to consumer prices or availability of supporting clinical trial data, but may depend more on the marketing capacity of the manufacturer. Major differences in frequency and dosing of anti-malarial regimens with identical anti-malarial compounds and the marketing of loose combinations were recorded.

Conclusion

Paediatric ACT is widely used for the treatment of uncomplicated malaria in young children. However, the majority of P-ACT formulations in use do not meet highest international quality standards evoking concerns for patients' safety and the induction of drug resistance. Improving the quality of currently marketed P-ACT should constitute a public health priority besides their adoption into official treatment recommendations.

Baseline in vitro activities of the antimalarials pyronaridine and methylene blue against Plasmodium falciparum isolates from Kenya

We have analyzed the in vitro activities of pyronaridine and methylene blue against 59 Plasmodium falciparum isolates from Kenya in association with polymorphisms in Pfcrt (codon 76), Pfmdr1 (codon 86), and Pfnhe (full sequence). The median inhibitory concentrations that kill 50% of parasites were 13.5 and 3.3 nM for pyronaridine and methylene blue, respectively. Their activities were not associated with polymorphisms in these genes. The drugs' high in vitro activities indicate that they would be efficacious against Kenyan isolates in vivo.