We still need artesunate monotherapy.
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Antimalarials↗
Biomedical subjects
Elizabeth Ashley
Publications and source records attributed to Elizabeth Ashley.
Efficacy and effectiveness of dihydroartemisinin-piperaquine versus artesunate-mefloquine in falciparum malaria: an open-label randomised comparison.
BACKGROUND: Artemisinin-based combinations are judged the best treatments for multidrug-resistant Plasmodium falciparum malaria. Artesunate-mefloquine is widely recommended in southeast Asia, but its high cost and tolerability profile remain obstacles to widespread deployment. To assess whether dihydroartemisinin-piperaquine is a suitable alternative to artesunate-mefloquine, we compared the safety, tolerability, efficacy, and effectiveness of the two regimens for the treatment of uncomplicated falciparum in western Myanmar (Burma). METHODS: We did an open randomised comparison of 3-day regimens of artesunate-mefloquine (12/25 mg/kg) versus dihydroartemisinin-piperaquine (6.3/50 mg/kg) for the treatment of children aged 1 year or older and in adults with uncomplicated falciparum malaria in Rakhine State, western Myanmar. Within each group, patients were randomly assigned supervised or non-supervised treatment. The primary endpoint was the PCR-confirmed parasitological failure rate by day 42. Failure rates at day 42 were estimated by Kaplan-Meier survival analysis. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN27914471. FINDINGS: Of 652 patients enrolled, 327 were assigned dihydroartemisinin-piperaquine (156 supervised and 171 not supervised), and 325 artesunate-mefloquine (162 and 163, respectively). 16 patients were lost to follow-up, and one patient died 22 days after receiving dihydroartemisinin-piperaquine. Recrudescent parasitaemias were confirmed in only two patients; the day 42 failure rate was 0.6% (95% CI 0.2-2.5) for dihydroartemisinin-piperaquine and 0 (0-1.2) for artesunate-mefloquine. Whole-blood piperaquine concentrations at day 7 were similar for patients with observed and non-observed dihydroartemisinin-piperaquine treatment. Gametocytaemia developed more frequently in patients who had received dihydroartemisinin-piperaquine than in those on artesunate-mefloquine: day 7, 18 (10%) of 188 versus five (2%) of 218; relative risk 4.2 (1.6-11.0) p=0.011. INTERPRETATION: Dihydroartemisinin-piperaquine is a highly efficacious and inexpensive treatment of multidrug-resistant falciparum malaria and is well tolerated by all age groups. The effectiveness of the unsupervised treatment, as in the usual context of use, equalled its supervised efficacy, indicating good adherence without supervision. Dihydroartemisinin-piperaquine is a good alternative to artesunate-mefloquine.
Adolescent↗
Brugada syndrome and anesthetic management.
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Adolescent↗
A case-control auditory evaluation of patients treated with artemether-lumefantrine.
Artemether-lumefantrine is the first registered, fixed, artemisinin-based combination treatment. Artemisinin derivatives are highly effective antimalarials with a favorable safety profile. Concerns remain over their potential neurotoxicity, although there has been no clinical evidence of this in humans. In animals (rats, dogs, and monkeys) artemether, a derivative of artemisinin is associated with an unusual toxicity pattern in specific brain nuclei involving the auditory and vestibular pathways. A recent report from Mozambique described a small but significant and irreversible hearing loss in patients exposed to artemether-lumefantrine. To explore this issue, we conducted a case-control study using tympanometry, audiometry and auditory brain-stem responses. We assessed 68 subjects who had been treated with artemether-lumefantrine within the previous five years and 68 age- and sex-matched controls living in the malarious region along the Thailand-Myanmar border. There were no differences in the test results between cases and controls. There was no neurophysiologic evidence of auditory brainstem toxicity that could be attributed to artemether-lumefantrine in this study population.
Acoustic Impedance Tests↗
Malaria.
Malaria is increasing worldwide due to the emergence and spread of drug resistant strains. This poses major health and economic problems for the population living in endemic areas and increases the risk of infections in travelers. The diagnosis of malaria relies on a biological proof of infection by microscopy or with a rapid test. The treatment must be initiated without delay preferably with an artemisinin containing regimen. Uncomplicated malaria can be treated with oral drugs while severe infections will be hospitalized and treated with injectables. Special attention will be given to the most susceptible groups: children and pregnant women.
Animals↗
Seasonal variation in hyperparasitaemia and gametocyte carriage in patients with Plasmodium falciparum malaria on the Thai-Burmese border.
Between January 2000 and December 2002 monthly rainfall was correlated with the proportion of patients with hyperparasitaemic Plasmodium falciparum malaria and with the proportion of patients with P. falciparum gametocytes. During the observation period 6953 cases of P. falciparum malaria were treated at the Shoklo Malaria Research Unit in Maela refugee camp on the Thai-Burmese border. Three hundred and seventy-five of these patients had >/=4% of parasitized red blood cells. Although there were more monthly malaria cases in the rainy season, rainfall was negatively correlated with the proportion of patients with hyperparasitaemia (Spearman's rho = -0.59, P < 0.001 ), and the proportion of gametocyte carriers among P. falciparum cases, (Spearman's rho = -0.39, P = 0.018). After controlling for age and the origin of the patient, the odds ratio for developing hyperparasitaemia during the dry season was 1.6 (95% CI 1.14-2.2; P = 0.006). The adjusted odds ratio for gametocyte carriage during the dry season was 1.3 (95% CI 1.03-1.6; P = 0.02). Migrations, changes in transmission patterns, the haematological burden of cumulative infections, and ultraviolet immunosuppression are discussed as potential explanations for these observations.
Adolescent↗
Mefloquine resistance in Plasmodium falciparum and increased pfmdr1 gene copy number.
BACKGROUND: The borders of Thailand harbour the world's most multidrug resistant Plasmodium falciparum parasites. In 1984 mefloquine was introduced as treatment for uncomplicated falciparum malaria, but substantial resistance developed within 6 years. A combination of artesunate with mefloquine now cures more than 95% of acute infections. For both treatment regimens, the underlying mechanisms of resistance are not known. METHODS: The relation between polymorphisms in the P falciparum multidrug resistant gene 1 (pfmdr1) and the in-vitro and in-vivo responses to mefloquine were assessed in 618 samples from patients with falciparum malaria studied prospectively over 12 years. pfmdr1 copy number was assessed by a robust real-time PCR assay. Single nucleotide polymorphisms of pfmdr1, P falciparum chloroquine resistance transporter gene (pfcrt) and P falciparum Ca2+ ATPase gene (pfATP6) were assessed by PCR-restriction fragment length polymorphism. FINDINGS: Increased copy number of pfmdr1 was the most important determinant of in-vitro and in-vivo resistance to mefloquine, and also to reduced artesunate sensitivity in vitro. In a Cox regression model with control for known confounders, increased pfmdr1 copy number was associated with an attributable hazard ratio (AHR) for treatment failure of 6.3 (95% CI 2.9-13.8, p<0.001) after mefloquine monotherapy and 5.4 (2.0-14.6, p=0.001) after artesunate-mefloquine therapy. Single nucleotide polymorphisms in pfmdr1 were associated with increased mefloquine susceptibility in vitro, but not in vivo. INTERPRETATION: Amplification in pfmdr1 is the main cause of resistance to mefloquine in falciparum malaria. RELEVANCE TO PRACTICE: Multidrug resistant P falciparum malaria is common in southeast Asia, but difficult to identify and treat. Genes that encode parasite transport proteins maybe involved in export of drugs and so cause resistance. In this study we show that increase in copy number of pfmdr1, a gene encoding a parasite transport protein, is the best overall predictor of treatment failure with mefloquine. Increase in pfmdr1 copy number predicts failure even after chemotherapy with the highly effective combination of mefloquine and 3 days' artesunate. Monitoring of pfmdr1 copy number will be useful in epidemiological surveys of drug resistance in P falciparum, and potentially for predicting treatment failure in individual patients.
ATP-Binding Cassette Transporters↗