Evidence of plasmodium falciparum Malaria multidrug resistance to artemisinin and piperaquine in Western Cambodia : dihydroartemisinin-piperaquine open-label multicenter clinical assessment

Western Cambodia is recognized as the epicentre of Plasmodium falciparum multidrug resistance. Recent reports of dihydroartemisinin-piperaquine efficacy, the latest generation of ACTs recommended by the WHO, prompted further investigations. Clinical efficacy of dihydroartemisinin-piperaquine in uncomplicated falciparum malaria was assessed in western and eastern Cambodia over 42 days. Day 7 piperaquine plasma concentrations were measured and day 0 isolates tested for in vitro susceptibilities to piperaquine and mefloquine, polymorphisms in the K13 gene and copy number of the mdr-1 gene (ACTRN12614000344695). 425 patients were recruited in 2011-2013. The proportion of patients with recrudescent infections was significantly higher in western (15.4%) compared to eastern Cambodia (2.5%, p<10-3). Day 7 PP plasma concentrations and PP median IC50 were independent of treatment outcomes, contrarily to mefloquine median IC50 which was found lower in recrudescent patient isolates (18.7 vs. 39.7 nM, p=0.005). The most significant risk factor associated with DHA-PP treatment failure was patients infected by parasites carrying the K13 mutant allele (OR=17.5, 95% CI: 1-308, p=0.04). Our data support evidence of falciparum PP resistance in western Cambodia, an area of widespread artemisinin resistance. New therapeutic strategies are needed urgently and must be tested such as the use of triple ACT

Plasmodium falciparum dihydroartemisinin-piperaquine failures in Cambodia are associated with mutant K13 parasites presenting high survival rates in novel piperaquine in vitro assays: retrospective and prospective investigations

International audienceBACKGROUND:The declining efficacy of dihydroartemisinin-piperaquine against Plasmodium falciparum in Cambodia, along with increasing numbers of recrudescent cases, suggests resistance to both artemisinin and piperaquine. Available in vitro piperaquine susceptibility assays do not correlate with treatment outcome. A novel assay using a pharmacologically relevant piperaquine dose/time exposure was designed and its relevance explored in retrospective and prospective studies.METHODS:The piperaquine survival assay (PSA) exposed parasites to 200 nM piperaquine for 48 hours and monitored survival 24 hours later. The retrospective study tested 32 culture-adapted, C580Y-K13 mutant parasites collected at enrolment from patients treated with a 3-day course of dihydroartemisinin-piperaquine and having presented or not with a recrudescence at day 42 (registered ACTRN12615000793516). The prospective study assessed ex vivo PSA survival rate alongside K13 polymorphism of isolates collected from patients enrolled in an open-label study with dihydroartemisinin-piperaquine for uncomplicated P. falciparum malaria in Cambodia (registered ACTRN12615000696594).RESULTS:All parasites from recrudescent cases had in vitro or ex vivo PSA survival rates ≥10%, a relevant cut-off value for piperaquine-resistance. Ex vivo PSA survival rates were higher for recrudescent than non-recrudescent cases (39.2% vs. 0.17%, P <1 × 10(-7)). Artemisinin-resistant K13 mutants with ex vivo PSA survival rates ≥10% were associated with 32-fold higher risk of recrudescence (95% CI, 4.5-224; P = 0.0005).CONCLUSION:PSA adequately captures the piperaquine resistance/recrudescence phenotype, a mainstay to identify molecular marker(s) and evaluate efficacy of alternative drugs. Combined ex vivo PSA and K13 genotyping provides a convenient monitor for both artemisinin and piperaquine resistance where dihydroartemisinin-piperaquine is used

Systematic or test-guided treatment for tuberculosis in HIV-infected adults

A trial involving HIV-infected patients with CD4+ T-cell counts below 100 cells per cubic millimeter compared strategies of systematic treatment for TB and treatment only if testing revealed infection. Systematic treatment was not better than treatment guided by testing with respect to the rate of death or bacterial infection. Background In regions with high burdens of tuberculosis and human immunodeficiency virus (HIV), many HIV-infected adults begin antiretroviral therapy (ART) when they are already severely immunocompromised. Mortality after ART initiation is high in these patients, and tuberculosis and invasive bacterial diseases are common causes of death. Methods We conducted a 48-week trial of empirical treatment for tuberculosis as compared with treatment guided by testing in HIV-infected adults who had not previously received ART and had CD4+ T-cell counts below 100 cells per cubic millimeter.Patients recruited in Ivory Coast, Uganda, Cambodia, and Vietnam were randomly assigned in a 1:1 ratio to undergo screening (Xpert MTB/RIF test, urinary lipoarabinomannan test, and chest radiography) to determine whether treatment for tuberculosis should be started or to receive systematic empirical treatment with rifampin, isoniazid, ethambutol, and pyrazinamide daily for 2 months, followed by rifampin and isoniazid daily for 4 months. The primary end point was a composite of death from any cause or invasive bacterial disease within 24 weeks (primary analysis) or within 48 weeks after randomization. Results A total of 522 patients in the systematic-treatment group and 525 in the guided-treatment group were included in the analyses.At week 24, the rate of death from any cause or invasive bacterial disease (calculated as the number of first events per 100 patient-years) was 19.4 with systematic treatment and 20.3 with guided treatment (adjusted hazard ratio, 0.95; 95% confidence interval [CI], 0.63 to 1.44). At week 48, the corresponding rates were 12.8 and 13.3 (adjusted hazard ratio, 0.97 [95% CI, 0.67 to 1.40]). At week 24, the probability of tuberculosis was lower with systematic treatment than with guided treatment (3.0% vs. 17.9%; adjusted hazard ratio, 0.15; 95% CI, 0.09 to 0.26), but the probability of grade 3 or 4 drug-related adverse events was higher with systematic treatment (17.4% vs. 7.2%; adjusted hazard ratio 2.57; 95% CI, 1.75 to 3.78).Serious adverse events were more common with systematic treatment. Conclusions Among severely immunosuppressed adults with HIV infection who had not previously received ART, systematic treatment for tuberculosis was not superior to test-guided treatment in reducing the rate of death or invasive bacterial disease over 24 or 48 weeks and was associated with more grade 3 or 4 adverse events.(Funded by the Agence Nationale de Recherches sur le Sida et les Hepatites Virales; STATIS ANRS 12290 ClinicalTrials.gov number,.

A surrogate marker of piperaquine-resistant Plasmodium falciparum malaria: a phenotype–genotype association study

International audienceBACKGROUND:Western Cambodia is the epicentre of Plasmodium falciparum multidrug resistance and is facing high rates of dihydroartemisinin-piperaquine treatment failures. Genetic tools to detect the multidrug-resistant parasites are needed. Artemisinin resistance can be tracked using the K13 molecular marker, but no marker exists for piperaquine resistance. We aimed to identify genetic markers of piperaquine resistance and study their association with dihydroartemisinin-piperaquine treatment failures.METHODS:We obtained blood samples from Cambodian patients infected with P falciparum and treated with dihydroartemisinin-piperaquine. Patients were followed up for 42 days during the years 2009-15. We established in-vitro and ex-vivo susceptibility profiles for a subset using piperaquine survival assays. We determined whole-genome sequences by Illumina paired-reads sequencing, copy number variations by qPCR, RNA concentrations by qRT-PCR, and protein concentrations by immunoblotting. Fisher's exact and non-parametric Wilcoxon rank-sum tests were used to identify significant differences in single-nucleotide polymorphisms or copy number variants, respectively, for differential distribution between piperaquine-resistant and piperaquine-sensitive parasite lines.FINDINGS:Whole-genome exon sequence analysis of 31 culture-adapted parasite lines associated amplification of the plasmepsin 2-plasmepsin 3 gene cluster with in-vitro piperaquine resistance. Ex-vivo piperaquine survival assay profiles of 134 isolates correlated with plasmepsin 2 gene copy number. In 725 patients treated with dihydroartemisinin-piperaquine, multicopy plasmepsin 2 in the sample collected before treatment was associated with an adjusted hazard ratio (aHR) for treatment failure of 20·4 (95% CI 9·1-45·5, p<0·0001). Multicopy plasmepsin 2 predicted dihydroartemisinin-piperaquine failures with 0·94 (95% CI 0·88-0·98) sensitivity and 0·77 (0·74-0·81) specificity. Analysis of samples collected across the country from 2002 to 2015 showed that the geographical and temporal increase of the proportion of multicopy plasmepsin 2 parasites was highly correlated with increasing dihydroartemisinin-piperaquine treatment failure rates (r=0·89 [95% CI 0·77-0·95], p<0·0001, Spearman's coefficient of rank correlation). Dihydroartemisinin-piperaquine efficacy at day 42 fell below 90% when the proportion of multicopy plasmepsin 2 parasites exceeded 22%.INTERPRETATION:Piperaquine resistance in Cambodia is strongly associated with amplification of plasmepsin 2-3, encoding haemoglobin-digesting proteases, regardless of the location. Multicopy plasmepsin 2 constitutes a surrogate molecular marker to track piperaquine resistance. A molecular toolkit combining plasmepsin 2 with K13 and mdr1 monitoring should provide timely information for antimalarial treatment and containment policie