WITHDRAWN: Artemether-lumefantrine for treating uncomplicated falciparum malaria

High efficacy of two artemisinin-based combinations: artesunate + sulfadoxine-pyrimethamine and artemether-lumefantrine for falciparum malaria in Yemen

BACKGROUND

Artesunate + sulfadoxine-pyrimethamine (AS + SP) has been the first-line treatment and artemether-lumefantrine (AL) the second-line treatment for uncomplicated falciparum malaria in Yemen since 2005. This paper reports the results of studies conducted to monitor therapeutic efficacy of these two drugs in sentinel sites in Yemen.

METHODS

Eight therapeutic efficacy studies were conducted in six sentinel sites during the period 2009-2013 in Yemen. Five studies were for the evaluation of AS + SP (total of 465 patients) and three studies (total of 268 patients) for the evaluation of AL. The studies were done according to standard WHO protocol 2009 with 28-day follow-up.

RESULTS

In the evaluation of AS + SP, the PCR-corrected cure rate was 98 % (95 % CI 92.2-99.5 %) in one site and 100 % in all of the other four sites. In the sites where AL was evaluated, the PCR-corrected cure rate was 100 % in all the sites. All patients were negative for asexual parasitaemia on day 3 in both the AS + SP and the AL groups. There was a higher rate of clearance of gametocytaemia in the AL-treated group when compared with the AS + SP groups from day 7 onwards.

CONCLUSION

AS + SP remains the effective drug for uncomplicated falciparum malaria in Yemen. AL is also highly effective and can be an appropriate alternative to AS + SP for the treatment of falciparum malaria. AL demonstrated a higher efficacy in clearing microscopic gametocytaemia than AS + SP.

TRIAL REGISTRATION

Trial registration number ACTRN12610000696099.

Therapeutic efficacy of artemether-lumefantrine in uncomplicated falciparum malaria in India

Background

Artemisinin-based combination therapy (ACT) is the treatment of choice for uncomplicated falciparum malaria. Artemether-lumefantrine (AL), a fixed dose co-formulation, has recently been approved for marketing in India, although it is not included in the National Drug Policy for treatment of malaria. Efficacy of short course regimen (4 × 4 tablets of 20 mg artemether plus 120 mg lumefantrine over 48 h) was demonstrated in India in the year 2000. However, low cure rates in Thailand and better plasma lumefantrine concentration profile with a six-dose regimen over three days, led to the recommendation of higher dose globally. This is the first report on the therapeutic efficacy of the six-dose regimen of AL in Indian uncomplicated falciparum malaria patients. The data generated will help in keeping the alternative ACT ready for use in the National Programme as and when required.

Methods

One hundred and twenty four subjects between two and fifty-five years of age living in two highly endemic areas of the country (Assam and Orissa) were enrolled for single arm, open label prospective study. The standard six-dose regimen of AL was administered over three days and was followed-up with clinical and parasitological evaluations over 28 days. Molecular markers msp-1 and msp-2 were used to differentiate the recrudescence and reinfection among the study subjects. In addition, polymorphism in pfmdr1 was also carried out in the samples obtained from patients before and after the treatment.

Results

The PCR corrected cure rates were high at both the sites viz. 100% (n = 53) in Assam and 98.6% (n = 71) in Orissa. The only treatment failure case on D7 was a malnourished child. The drug was well tolerated with no adverse events. Patients had pre-treatment carriage of wild type codons at positions 86 (41.7%, n = 91) and 184 (91.3%, n = 91) of pfmdr1 gene.

Conclusion

AL is safe and effective drug for the treatment of acute uncomplicated falciparum malaria in India. The polymorphism in pfmdr1 gene is not co-related with clinical outcome. However, treatment failure can also occur due to incomplete absorption of the drug as is suspected in one case of failure at D7 in the study. AL can be a viable alternative of artesunate plus sulphadoxine/pyrimethamine (AS + SP), however, the drug should be used rationally and efficacy needs to be monitored periodically.

Artemether-lumefantrine versus artesunate plus amodiaquine for treating uncomplicated childhood malaria in Nigeria: randomized controlled trial

BACKGROUND

The therapeutic efficacy of artesunate plus amodiaquine and artemether/lumefantrine were assessed in an area of Nigeria with high levels of Plasmodium falciparum resistance to chloroquine and sulphadoxine-pyrimethamine.

PARTICIPANTS

Children aged 6 to 59 months with uncomplicated P. falciparum infection and parasite density 1,000 to 200,000 parasites/microL enrolled following informed consent by parents.

METHODS

Eligible children were randomly assigned to receive either a 3-day course of artesunate (4 mg/kg) plus amodiaquine (10 mg/kg) or 6-dose course of artemether/lumefantrine (20/120 mg tablets) over three days. Patients were followed up with clinical and laboratory assessments until day 14 using standard WHO in-vivo antimalarial drug test protocol.

RESULTS

A total 119 eligible children were enrolled but 111 completed the study. Adequate clinical and parasitological response (ACPR) was 47 (87.0%) and 47 (82.5%) for artemether-lumefantrine (AL) and artesunate+amodiaquine (AAMQ) respectively (OR 0.7, 95% confidence interval 0.22 to 2.22). Early treatment failure (ETF) occurred in one participant (1.8%) treated with AAQ but in none of those with AL. Two (3.7%) patients in the AL group and none in the AAQ group had late clinical failure. Late parasitological failure was observed in 9 (15.8) and 5 (9.3%) of patients treated with AAQ and AL respectively. None of participants had a serious adverse event.

CONCLUSION

Artemether-lumenfantrine and artesunate plus amodiaquine have high and comparable cure rates and tolerability among under-five children in Calabar, Nigeria.

Artemether-lumefantrine (four-dose regimen) for treating uncomplicated falciparum malaria

BACKGROUND

The World Health Organization recommends artemether-lumefantrine, an expensive drug, as a treatment for uncomplicated malaria. We sought evidence of the superiority of the four-dose regimen over existing treatments.

OBJECTIVES

To evaluate the four-dose regimen of artemether-lumefantrine for treating uncomplicated falciparum malaria.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group Specialized Register (October 2005), CENTRAL (The Cochrane Library 2005, Issue 3), MEDLINE (1966 to October 2005), EMBASE (1988 to October 2005), LILACS (1982 to October 2005), conference proceedings, and reference lists of articles. We also contacted experts in malaria research and the pharmaceutical company that manufactures artemether-lumefantrine.

SELECTION CRITERIA

Randomized controlled trials comparing four doses of artemether-lumefantrine with standard treatment regimens (single drug or combination), or six doses of artemether-lumefantrine, for treating uncomplicated falciparum malaria.

DATA COLLECTION AND ANALYSIS

Two authors independently applied inclusion criteria to potentially relevant trials, assessed trial quality, and extracted data, including adverse events. Total failure by day 28 (day 42 for sulfadoxine-pyrimethamine and day 63 for mefloquine) was the primary outcome.

MAIN RESULTS

Seven trials (2057 participants) tested a four-dose regimen. More people tended to fail treatment with artemether-lumefantrine than with other drugs, including sulfadoxine-pyrimethamine (247 participants, 1 trial), halofantrine (86 participants, 1 trial), and mefloquine (233 participants, 1 trial; difference statistically significant for mefloquine). When compared with chloroquine, artemether-lumefantrine was better in two trials (378 participants), but over 50% of the participants treated with chloroquine had total failure by day 28. Fewer people failed treatment with the six-dose regimen compared to the four-dose regimen (RR 7.71, 95% CI 2.99 to 19.88; 306 participants, 1 trial).

AUTHORS' CONCLUSIONS

The four-dose regimen of artemether-lumefantrine seems to be less effective than regimens against which it has been tested. The six-dose regimen is superior to four-dose regimen.

Artemether-lumefantrine (six-dose regimen) for treating uncomplicated falciparum malaria

BACKGROUND

The World Health Organization recommends artemether-lumefantrine for treating uncomplicated malaria. We sought evidence of superiority of the six-dose regimen over existing treatment regimens as well as its effectiveness in clinical situations.

OBJECTIVES

To evaluate the six-dose regimen of artemether-lumefantrine for treating uncomplicated falciparum malaria.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group Specialized Register (April 2005), CENTRAL (The Cochrane Library Issue 1, 2005), MEDLINE (1966 to April 2005), EMBASE (1974 to April 2005), LILACS (1982 to April 2005), conference proceedings, and reference lists of articles. We also contacted experts in malaria research and the pharmaceutical company that manufactures artemether-lumefantrine.

SELECTION CRITERIA

Randomized controlled trials comparing six doses of artemether-lumefantrine administered orally with standard treatment regimens (single drug or combination), or supervised with unsupervised treatment, for uncomplicated falciparum malaria.

DATA COLLECTION AND ANALYSIS

Two authors independently applied inclusion criteria to potentially relevant trials, assessed trial quality, and extracted data, including adverse events. Total failure by day 28 (day 42 for sulfadoxine-pyrimethamine and day 63 for mefloquine) was the primary outcome.

MAIN RESULTS

Nine trials (4547 participants) tested the six-dose regimen. Total failure at day 28 for artemether-lumefantrine was lower when compared with amodiaquine (270 participants, 1 trial), amodiaquine plus sulfadoxine-pyrimethamine (507 participants, 1 trial), but not with chloroquine plus sulfadoxine-pyrimethamine (201 participants, 2 trials). In comparisons with artemisinin derivative combinations, artemether-lumefantrine performed better than amodiaquine plus artesunate (668 participants, 2 trials), worse than mefloquine plus artesunate (270 participants, 4 trials), and no differently to dihydroartemisinin-napthoquine-trimethoprim (89 participants, 1 trial).

AUTHORS' CONCLUSIONS

The six-dose regimen of artemether-lumefantrine appears more effective than antimalarial regimens not containing artemisinin derivatives.

Malaria

Malaria is the most important parasitic infection in people, accounting for more than 1 million deaths a year. Malaria has become a priority for the international health community and is now the focus of several new initiatives. Prevention and treatment of malaria could be greatly improved with existing methods if increased financial and labour resources were available. However, new approaches for prevention and treatment are needed. Several new drugs are under development, which are likely to be used in combinations to slow the spread of resistance, but the high cost of treatments would make sustainability difficult. Insecticide-treated bed-nets provide a simple but effective means of preventing malaria, especially with the development of longlasting nets in which insecticide is incorporated into the net fibres. One malaria vaccine, RTS,S/AS02, has shown promise in endemic areas and will shortly enter further trials. Other vaccines are being studied in clinical trials, but it will probably be at least 10 years before a malaria vaccine is ready for widespread use.

Antimalarial compounds: from bench to bedside

The emergence and spread of drug-resistant malaria parasites is the major threat to effective malaria control. So far, malaria control has relied heavily on a restricted number of chemically related drugs belonging to either the quinoline or the antifolate groups. Only recently have the artemisinin-type compounds been used widely, predominantly in Southeast Asia. Experience has shown that resistance eventually curtails the life span of antimalarial drugs. If measures are not applied to contain resistance, the investment put into the development of new drugs will be squandered.

Current efforts focus, on the one hand, on research into novel compounds with mechanisms of action that are different to the traditionally used drugs,and, on the other hand, on measures to prevent or delay resistance when drugs are introduced. Drug discovery and development are long, risky and expensive ventures. Whilst very few new antimalarial drugs were developed in the last quarter of the 20th century (only four of the nearly 1400 drugs registered worldwide during 1975-1999), various private and public institutions are at work to discover and develop new compounds. Today, the antimalarial pipeline is relatively healthy. Projects are underway at different stages of drug development, from pre-development to registration. However, there is relatively little novelty, as current development projects still rely upon the traditional quinoline, antifolate and, in particular, artemisinin compounds. New structures are expected from the more upstream discovery efforts but it will take time before they become drugs.

Therefore, whilst waiting for the drugs of tomorrow, there is a pressing need for immediately available, effective and affordable drugs that will have long life spans. Drug combinations that have independent modes of action are seen as a way of enhancing efficacy while ensuring mutual protection against resistance.

Most research work has focussed on the use of artesunate combined with currently used standard drugs, namely mefloquine, amodiaquine,sulfadoxine/pyrimethamine and chloroquine. There is clear evidence that combinations improve efficacy without increasing toxicity. However, the absolute cure rates that are achieved by combinations vary widely and are dependent on the level of resistance of the standard drug. From these studies,further work is underway to produce fixed dose combinations that will be packaged in blister packs. Malaria control programmes need efficacious drugs that can be used with ease by the populations of endemic countries.

This review will summarise current antimalarial drug developments and outline recent clinical research that aims to bring artemisinin-based combinations to those that need them most.

Safety, efficacy and determinants of effectiveness of antimalarial drugs during pregnancy: implications for prevention programmes in Plasmodium falciparum-endemic sub-Saharan Africa

Plasmodium falciparum malaria in pregnancy poses substantial risk to a pregnant woman and her neonate through anaemia and low birth weight (LBW), respectively, and is responsible for up to 35% of preventable LBW in malaria-endemic areas. Chemoprophylaxis or intermittent preventive treatment (IPT) with an effective antimalarial can ameliorate the adverse effects of malaria during pregnancy. Current guidelines from the WHO recommend that women in highly malarious areas receive IPT with an effective antimalarial. Two central considerations in evaluating drugs for use during pregnancy are safety for the mother and her foetus and effectiveness, which is determined by efficacy, cost, availability, deliverability and acceptability of the drug. These factors may be scored and potential drugs or drug combinations ranked in order of potential effectiveness for use in prevention programmes. The seven most promising regimens are all IPT, primarily because they are more easily delivered and less expensive than chemoprophylaxis. Currently, IPT with sulphadoxine-pyrimethamine (SP) is more likely to have the best overall effectiveness in preventing adverse outcomes associated with malaria in pregnancy. Its low cost, wide availability, easy deliverability and acceptability make it the clear choice in countries where efficacy of the drug remains good. For countries where resistance to SP is rising or already high, amodiaquine (alone or in combination with SP or artesunate) artesunate + SP, chlorproguanil-dapsone (with and without artesunate) and artemether-lumefantrine require urgent evaluation for use in pregnancy.