A random survey of the prevalence of falsified and substandard antibiotics in the Lao PDR.

OBJECTIVES: In 2012, a stratified random survey, using mystery shoppers, was conducted to investigate the availability and quality of antibiotics sold to patients in the private sector in five southern provinces of the Lao People's Democratic Republic (Laos). METHODS: A total of 147 outlets were sampled in 10 districts. The active pharmaceutical ingredient (API) content measurements for 909 samples, including nine APIs (amoxicillin, ampicillin, ceftriaxone, ciprofloxacin, doxycycline, ofloxacin, sulfamethoxazole, tetracycline and trimethoprim), were determined using HPLC. RESULTS: All the analysed samples contained the stated API and we found no evidence for falsification. All except one sample had all the units tested with %API values between 75% and 125% of the content stated on the label. However, we identified the presence of substandard antibiotics: 19.6% (201/1025) of samples had their units outside the 90%-110% content of the label claim and 18.3% (188/1025) of the samples had units outside the International Pharmacopoeia/United States Pharmacopoeia assay (percentage of label claim) specifications. Trimethoprim had a high number of samples [51.6% (64)] with units below the limit range, followed by ceftriaxone [42.9% (3)] and sulfamethoxazole [34.7% (43)]. Doxycycline, ofloxacin and ciprofloxacin had the highest number of samples with high API content: 43.7% (38), 14.7% (10) and 11.8% (2), respectively. Significant differences in %API were found between stated countries of manufacture and stated manufacturers. CONCLUSIONS: With the global threat of antimicrobial resistance on patient outcomes, greater understanding of the role of poor-quality antibiotics is needed. Substandard antibiotics will have reduced therapeutic efficacy, impacting public health and control of bacterial infections.

A random survey of the prevalence of falsified and substandard antibiotics in the Lao PDR.

OBJECTIVES: In 2012, a stratified random survey, using mystery shoppers, was conducted to investigate the availability and quality of antibiotics sold to patients in the private sector in five southern provinces of the Lao People's Democratic Republic (Laos). METHODS: A total of 147 outlets were sampled in 10 districts. The active pharmaceutical ingredient (API) content measurements for 909 samples, including nine APIs (amoxicillin, ampicillin, ceftriaxone, ciprofloxacin, doxycycline, ofloxacin, sulfamethoxazole, tetracycline and trimethoprim), were determined using HPLC. RESULTS: All the analysed samples contained the stated API and we found no evidence for falsification. All except one sample had all the units tested with %API values between 75% and 125% of the content stated on the label. However, we identified the presence of substandard antibiotics: 19.6% (201/1025) of samples had their units outside the 90%-110% content of the label claim and 60.2% (617/1025) of the samples had units outside of the International Pharmacopoeia uniformity of content limit range. Amoxicillin had a high number of samples [67.1% (151)] with units above the limit range, followed by ciprofloxacin [58.8% (10)] and ofloxacin [57.4% (39)]. Ceftriaxone, trimethoprim and sulfamethoxazole had the highest number of samples with low API content: 57.1% (4), 51.6% (64) and 34.7% (43), respectively. Significant differences in %API were found between stated countries of manufacture and stated manufacturers. CONCLUSIONS: With the global threat of antimicrobial resistance to patient outcomes, greater understanding of the role of poor-quality antibiotics is needed. Substandard antibiotics will have reduced therapeutic efficacy, impacting public health and control of bacterial infections.

A Worldwide Map of Plasmodium falciparum K13-Propeller Polymorphisms.

BACKGROUND: Recent gains in reducing the global burden of malaria are threatened by the emergence of Plasmodium falciparum resistance to artemisinins. The discovery that mutations in portions of a P. falciparum gene encoding kelch (K13)-propeller domains are the major determinant of resistance has provided opportunities for monitoring such resistance on a global scale. METHODS: We analyzed the K13-propeller sequence polymorphism in 14,037 samples collected in 59 countries in which malaria is endemic. Most of the samples (84.5%) were obtained from patients who were treated at sentinel sites used for nationwide surveillance of antimalarial resistance. We evaluated the emergence and dissemination of mutations by haplotyping neighboring loci. RESULTS: We identified 108 nonsynonymous K13 mutations, which showed marked geographic disparity in their frequency and distribution. In Asia, 36.5% of the K13 mutations were distributed within two areas--one in Cambodia, Vietnam, and Laos and the other in western Thailand, Myanmar, and China--with no overlap. In Africa, we observed a broad array of rare nonsynonymous mutations that were not associated with delayed parasite clearance. The gene-edited Dd2 transgenic line with the A578S mutation, which expresses the most frequently observed African allele, was found to be susceptible to artemisinin in vitro on a ring-stage survival assay. CONCLUSIONS: No evidence of artemisinin resistance was found outside Southeast Asia and China, where resistance-associated K13 mutations were confined. The common African A578S allele was not associated with clinical or in vitro resistance to artemisinin, and many African mutations appear to be neutral. (Funded by Institut Pasteur Paris and others.).

Causes of Fever in Rural Southern Laos.

The etiology of fever in rural Lao People's Democratic Republic (Laos) has remained obscure until recently owing to the lack of laboratory facilities. We conducted a study to determine the causes of fever among 229 patients without malaria in Savannakhet Province, southern Laos; 52% had evidence of at least one diagnosis (45% with single and 7% with apparent multiple infections). Among patients with only one diagnosis, dengue (30.1%) was the most common, followed by leptospirosis (7.0%), Japanese encephalitis virus infection (3.5%), scrub typhus (2.6%), spotted fever group infection (0.9%), unspecified flavivirus infection (0.9%), and murine typhus (0.4%). We discuss the empirical treatment of fever in relation to these findings.

A Repeat Random Survey of the Prevalence of Falsified and Substandard Antimalarials in the Lao PDR: A Change for the Better.

In 2003, a stratified random sample survey was conducted in the Lao People's Democratic Republic (Laos) to study the availability and quality of antimalarials in the private sector. In 2012, this survey was repeated to allow a statistically valid analysis of change through time. The counterfeit detection device 3 (CD-3) was used to assess packaging quality in the field and HPLC and mass spectroscopy analysis chemical analysis performed. The availability of oral artesunate monotherapies had significantly decreased from 22.9% (22) of 96 outlets in southern Laos in 2003 to 4.8% (7) of 144 outlets in 2012 (P < 0.0001). All the samples collected in the 2012 survey contained the correct active pharmaceutical ingredients (APIs) in contrast to the 21 (84%) falsified artesunate samples found in the 2003 survey. Although none of the medicines found in 2012 survey had evidence for falsification, 25.4% (37) of the samples were outside the 90-110% pharmacopeial limits of the label claim, suggesting that they were substandard or degraded. Results obtained from this survey show that patients are still exposed to poorly manufactured drugs or to ineffective medicines such as chloroquine. The quality of artemisinin-based combination therapies (ACTs) used in Laos needs to be monitored, since falsified ACTs would have devastating consequences in public health.

Genetic architecture of artemisinin-resistant Plasmodium falciparum.

We report a large multicenter genome-wide association study of Plasmodium falciparum resistance to artemisinin, the frontline antimalarial drug. Across 15 locations in Southeast Asia, we identified at least 20 mutations in kelch13 (PF3D7_1343700) affecting the encoded propeller and BTB/POZ domains, which were associated with a slow parasite clearance rate after treatment with artemisinin derivatives. Nonsynonymous polymorphisms in fd (ferredoxin), arps10 (apicoplast ribosomal protein S10), mdr2 (multidrug resistance protein 2) and crt (chloroquine resistance transporter) also showed strong associations with artemisinin resistance. Analysis of the fine structure of the parasite population showed that the fd, arps10, mdr2 and crt polymorphisms are markers of a genetic background on which kelch13 mutations are particularly likely to arise and that they correlate with the contemporary geographical boundaries and population frequencies of artemisinin resistance. These findings indicate that the risk of new resistance-causing mutations emerging is determined by specific predisposing genetic factors in the underlying parasite population.

Independent emergence of artemisinin resistance mutations among Plasmodium falciparum in Southeast Asia.

BACKGROUND: The emergence of artemisinin-resistant Plasmodium falciparum in Southeast Asia threatens malaria treatment efficacy. Mutations in a kelch protein encoded on P. falciparum chromosome 13 (K13) have been associated with resistance in vitro and in field samples from Cambodia. METHODS: P. falciparum infections from artesunate efficacy trials in Bangladesh, Cambodia, Laos, Myanmar, and Vietnam were genotyped at 33 716 genome-wide single-nucleotide polymorphisms (SNPs). Linear mixed models were used to test associations between parasite genotypes and parasite clearance half-lives following artesunate treatment. K13 mutations were tested for association with artemisinin resistance, and extended haplotypes on chromosome 13 were examined to determine whether mutations arose focally and spread or whether they emerged independently. RESULTS: The presence of nonreference K13 alleles was associated with prolonged parasite clearance half-life (P = 1.97 × 10(-12)). Parasites with a mutation in any of the K13 kelch domains displayed longer parasite clearance half-lives than parasites with wild-type alleles. Haplotype analysis revealed both population-specific emergence of mutations and independent emergence of the same mutation in different geographic areas. CONCLUSIONS: K13 appears to be a major determinant of artemisinin resistance throughout Southeast Asia. While we found some evidence of spreading resistance, there was no evidence of resistance moving westward from Cambodia into Myanmar.

Spread of artemisinin resistance in Plasmodium falciparum malaria.

BACKGROUND: Artemisinin resistance in Plasmodium falciparum has emerged in Southeast Asia and now poses a threat to the control and elimination of malaria. Mapping the geographic extent of resistance is essential for planning containment and elimination strategies. METHODS: Between May 2011 and April 2013, we enrolled 1241 adults and children with acute, uncomplicated falciparum malaria in an open-label trial at 15 sites in 10 countries (7 in Asia and 3 in Africa). Patients received artesunate, administered orally at a daily dose of either 2 mg per kilogram of body weight per day or 4 mg per kilogram, for 3 days, followed by a standard 3-day course of artemisinin-based combination therapy. Parasite counts in peripheral-blood samples were measured every 6 hours, and the parasite clearance half-lives were determined. RESULTS: The median parasite clearance half-lives ranged from 1.9 hours in the Democratic Republic of Congo to 7.0 hours at the Thailand-Cambodia border. Slowly clearing infections (parasite clearance half-life >5 hours), strongly associated with single point mutations in the "propeller" region of the P. falciparum kelch protein gene on chromosome 13 (kelch13), were detected throughout mainland Southeast Asia from southern Vietnam to central Myanmar. The incidence of pretreatment and post-treatment gametocytemia was higher among patients with slow parasite clearance, suggesting greater potential for transmission. In western Cambodia, where artemisinin-based combination therapies are failing, the 6-day course of antimalarial therapy was associated with a cure rate of 97.7% (95% confidence interval, 90.9 to 99.4) at 42 days. CONCLUSIONS: Artemisinin resistance to P. falciparum, which is now prevalent across mainland Southeast Asia, is associated with mutations in kelch13. Prolonged courses of artemisinin-based combination therapies are currently efficacious in areas where standard 3-day treatments are failing. (Funded by the U.K. Department of International Development and others; ClinicalTrials.gov number, NCT01350856.).

Thiamin supplementation does not reduce the frequency of adverse events after anti-malarial therapy among patients with falciparum malaria in southern Laos.

BACKGROUND: In a recent study one third of Lao patients presenting with uncomplicated Plasmodium falciparum malaria had biochemical evidence of thiamin deficiency, which was associated with a higher incidence of adverse events. Thiamin supplementation might, therefore, reduce adverse events in this population. METHODS: An exploratory, double-blind, parallel group, placebo-controlled, superiority trial of thiamin supplementation in patients of all ages with uncomplicated and severe falciparum malaria was conducted in Xepon District, Savannakhet Province, southern Laos. Patients were randomly assigned to either oral thiamin 10 mg/day for 7 days immediately after standard anti-malarial treatment then 5 mg daily until day 42, or identical oral placebo. RESULTS: After interim analyses when 630 patients (314 in thiamin and 316 in placebo groups) had been recruited, the trial was discontinued on the grounds of futility. On admission biochemical thiamin deficiency (alpha ≥ 25%) was present in 27% of patients and 9% had severe deficiency (alpha > 31%). After 42 days of treatment, the frequency of thiamin deficiency was lower in the thiamin (2%, 1% severe) compared to the placebo (11%, 3% severe) groups (p < 0.001 and p = 0.05), respectively. Except for diarrhoea, 7% in the placebo compared to 3% in the thiamin group (p = 0.04), and dizziness on day 1 (33% vs 25%, p = 0.045), all adverse events were not significantly different between the groups (p > 0.05). Clinical, haematological, and parasitological responses to treatment did not differ significantly between the two groups. CONCLUSION: Thiamin supplementation reduced biochemical thiamin deficiency among Lao malaria patients following anti-malarial drug treatment, but it did not reduce the frequency of adverse events after anti-malarial therapy or have any detected clinical or parasitological impact. TRIAL REGISTRATION: ISRCTN 85411059.

Efficacy of artemether-lumefantrine, the nationally-recommended artemisinin combination for the treatment of uncomplicated falciparum malaria, in southern Laos.

BACKGROUND: The Lao Government changed the national policy for uncomplicated Plasmodium falciparum malaria from chloroquine to artemether-lumefantrine (AL) in 2005. Since then, no information on AL efficacy has been reported. With evidence of resistance to artemisinin derivatives in adjacent Cambodia, there has been a concern as to AL efficacy. Monitoring of AL efficacy would help the Lao Government to make decisions on appropriate malaria treatment. METHODS: The efficacy of a three-day, twice daily oral artemether-lumefantrine for the treatment of uncomplicated falciparum malaria in Xepon District, Savannakhet Province, southern Laos was studied over 42 days follow-up. This was part of a trial of thiamin supplementation in falciparum malaria. RESULTS: Of 630 patients with P. falciparum enrolled in the trial of thiamin treatment, 549 (87%, 357 children ≤15 years and 192 adults) were included in this study. The per protocol 42-day cure rates were 97% (524/541) [96% (337/352) for children and 99% (187/189) for adults, p = 0.042]. By conventional intention-to-treat analysis, the 42-day cure rates adjusted for re-infection, were 97% (532/549) [96% (342/357) in children and 99% (190/192) in adults, p = 0.042]. The proportion of patients who remained parasitaemic at day 1 after treatment was significantly higher in children [33% (116/356)] compared to adults [15% (28/192)] (p < 0.001) and only one adult patient had detectable parasitaemia on day 2. There were no serious adverse events. Potential side effects after treatment were reported more commonly in adults (32%) compared to children (15%) (p < 0.001). Patients with recrudescent infections were significantly younger, had longer mean time to fever clearance, and had longer median time to parasite clearance compared to those who were cured. CONCLUSIONS: The current nationally-recommended anti-malarial treatment (artemether-lumefantrine) remains highly efficacious for the treatment of uncomplicated falciparum malaria five years after introduction in Laos. Regular monitoring is required in case artemisinin-resistant P. falciparum parasites should appear. TRIAL REGISTRATION: ISRCTN85411059.

No evidence for spread of Plasmodium falciparum artemisinin resistance to Savannakhet Province, Southern Laos.

We conducted an open-label, randomized clinical trial to assess parasite clearance times (PCT) and the efficacy of 4 mg/kg (group 1, n = 22) and 2 mg/kg (group 2, n = 22) of oral artesunate for three days followed by artemether-lumefantrine in patients with uncomplicated Plasmodium falciparum malaria at Xepon Interdistrict Hospital, Savannakhet Province in southern Laos. Slides were read in duplicate. The overall mean (95% confidence interval; range) PCT in hours was 23.2 (21.2-25.3; 12-46) and 22.4 (20.3-24.5; 12-46) for the first and second microscopists, respectively (P = 0.57). Ten (23%) patients remained parasitemic on day 1 after treatment (4 [18%] in group 1 and 6 [27%] in group 2; P = 0.47). No patient had patent asexual parasitemia on the second and third days of treatment. The 42-day polymerase chain reaction-corrected cure rates were 100% in both treatment groups. Serious adverse events did not develop during or after treatment in any patients. In conclusion, no evidence of P. falciparum in vivo resistance to artesunate was found in southern Laos.

A phase III, randomized, non-inferiority trial to assess the efficacy and safety of dihydroartemisinin-piperaquine in comparison with artesunate-mefloquine in patients with uncomplicated Plasmodium falciparum malaria in southern Laos.

We conducted an open, randomized clinical trial of oral dihydroartemisinin-piperaquine (DP) versus artesunate-mefloquine (AM) in 300 patients in Laos with uncomplicated Plasmodium falciparum malaria as part of a multicentre study in Asia. Survival analysis and adjustment for re-infection showed that the 63-day cure rates (95% confidence interval [CI]) were 100% for AM and 99.5% (96.4-99.8%) for DP. The 63-day cure rates per protocol were 99% (97 of 98) for AM and 99.5% (196 of 197) for DP (P = 0.55). The difference (AM minus DP) in cure rates (95% CI) was -0.5% (-5.1 to 2.0%), which is within the 5% non-inferiority margin. The median fever and parasite clearance times were also similar for AM and DP. The proportion of patients with at least one recorded potential adverse event was significantly higher in the AM group (38 of 87, 44%) than in the DP group (57 of 182, 31%) (relative risk = 0.6, 95% CI = 0.4-0.9; P = 0.04). Dihydroartemisinin-piperaquine is not inferior to AM in the treatment of uncomplicated P. falciparum malaria in Laos and is associated with fewer adverse effects. The results of this study were similar to those of the larger multicentre study.

An open-label, randomised study of dihydroartemisinin-piperaquine versus artesunate-mefloquine for falciparum malaria in Asia.

BACKGROUND: The artemisinin-based combination treatment (ACT) of dihydroartemisinin (DHA) and piperaquine (PQP) is a promising novel anti-malarial drug effective against multi-drug resistant falciparum malaria. The aim of this study was to show non-inferiority of DHA/PQP vs. artesunate-mefloquine (AS+MQ) in Asia. METHODS AND FINDINGS: This was an open-label, randomised, non-inferiority, 63-day follow-up study conducted in Thailand, Laos and India. Patients aged 3 months to 65 years with Plasmodium falciparum mono-infection or mixed infection were randomised with an allocation ratio of 2:1 to a fixed-dose DHA/PQP combination tablet (adults: 40 mg/320 mg; children: 20 mg/160 [DOSAGE ERROR CORRECTED] mg; n = 769) or loose combination of AS+MQ (AS: 50 mg, MQ: 250 mg; n = 381). The cumulative doses of study treatment over the 3 days were of about 6.75 mg/kg of DHA and 54 mg/kg of PQP and about 12 mg/kg of AS and 25 mg/kg of MQ. Doses were rounded up to the nearest half tablet. The primary endpoint was day-63 polymerase chain reaction (PCR) genotype-corrected cure rate. Results were 87.9% for DHA/PQP and 86.6% for AS+MQ in the intention-to-treat (ITT; 97.5% one-sided confidence interval, CI: >-2.87%), and 98.7% and 97.0%, respectively, in the per protocol population (97.5% CI: >-0.39%). No country effect was observed. Kaplan-Meier estimates of proportions of patients with new infections on day 63 (secondary endpoint) were significantly lower for DHA/PQP than AS+MQ: 22.7% versus 30.3% (p = 0.0042; ITT). Overall gametocyte prevalence (days 7 to 63; secondary endpoint), measured as person-gametocyte-weeks, was significantly higher for DHA/PQP than AS+MQ (10.15% versus 4.88%; p = 0.003; ITT). Fifteen serious adverse events were reported, 12 (1.6%) in DHA/PQP and three (0.8%) in AS+MQ, among which six (0.8%) were considered related to DHA/PQP and three (0.8%) to AS+MQ. CONCLUSIONS: DHA/PQP was a highly efficacious drug for P. falciparum malaria in areas where multidrug parasites are prevalent. The DHA/PQP combination can play an important role in the first-line treatment of uncomplicated falciparum malaria. TRIAL REGISTRATION: Controlled-Trials.com ISRCTN81306618.

Thiamin deficiency and uncomplicated falciparum malaria in Laos.

OBJECTIVE: Thiamin deficiency complicates severe Plasmodium falciparum malaria in Thailand and may contribute to acidosis. We therefore estimated the frequency of biochemical thiamin deficiency in patients presenting with uncomplicated falciparum malaria in southern Laos. METHODS: Red cell transketolase activation coefficients (alpha) were measured in 310 patients presenting with uncomplicated falciparum malaria and 42 days after starting treatment. RESULTS: Twelve per cent of patients had biochemical evidence of severe deficiency (alpha values >1.31) at presentation, declining to 3% 42 days later. CONCLUSION: Thiamin deficiency was common in Lao patients admitted with uncomplicated P. falciparum infection and was reduced following treatment of malaria and multivitamin supplementation. The role of this preventable and treatable disorder in malaria and other acute infections, and the incidence of beriberi in rural Laos, needs further investigation.

Randomized comparison of chloroquine plus sulfadoxine-pyrimethamine versus artesunate plus mefloquine versus artemether-lumefantrine in the treatment of uncomplicated falciparum malaria in the Lao People's Democratic Republic.

BACKGROUND: Recent clinical trials in the Lao People's Democratic Republic have demonstrated that chloroquine and sulfadoxine-pyrimethamine, which are national malaria treatment policy, are no longer effective in the treatment of uncomplicated Plasmodium falciparum malaria. METHODS: A randomized comparison of 3 oral antimalarial combinations--chloroquine plus sulfadoxine-pyrimethamine versus artesunate plus mefloquine versus artemether-lumefantrine--with 42-day follow-up period, was conducted among 330 patients with acute uncomplicated falciparum malaria in southern Laos. RESULTS: The 42-day cure rates, as determined by intention-to-treat analysis and adjusted for reinfection, were 100%, 97%, and 93% for the groups receiving artesunate plus mefloquine, artemether-lumefantrine, and chloroquine plus sulfadoxine-pyrimethamine, respectively. Of 8 patients receiving chloroquine plus sulfadoxine-pyrimethamine who experienced treatment failure, 6 had early treatment failure. The mean parasite clearance time was significantly longer in patients treated with chloroquine plus sulfadoxine-pyrimethamine (2.9 days; 95% confidence interval [CI], 2.8-3.0 days) than in those treated with artesunate plus mefloquine (2.07 days; 95% CI, 2.0-2.1 days; P<.001) and artemether-lumefantrine (2.08 days; 95% CI, 2.0-2.1 days; P<.001). Cure rates with artemether-lumefantrine were high despite low mean daily dietary fat intake (13.8 g; 95% CI, 12.5-15.1 g) and day 7 plasma lumefantrine concentrations (0.47 mu g/mL; 95% CI, 0.38-0.56 mu g/mL). CONCLUSION: Oral artesunate plus mefloquine and artemether-lumefantrine are highly effective for the treatment of uncomplicated falciparum malaria in Laos.

A randomized comparison of oral chloroquine and sulfadoxine-pyrimethamine for the treatment of uncomplicated Plasmodium falciparum malaria in Laos.

Between June and October 2000 we conducted the first randomized trial in Laos comparing chloroquine (CQ) with sulfadoxine-pyrimethamine (SP) in the treatment of uncomplicated Plasmodium falciparum malaria (n = 29, 42-d follow-up, age > 5 years). The proportion of patients with treatment failure was high (CQ = 78%, RIII 46%; SP = 36%, RIII 15%). The treatment policy for uncomplicated P. falciparum malaria in Laos needs to be reviewed urgently.