Efficacy and safety of triple combination therapy with artesunate-amodiaquine-methylene blue for falciparum malaria in children: a randomized controlled trial in Burkina Faso.

BACKGROUND: Methylene blue (MB) has been shown to be safe and effective against falciparum malaria in Africa and to have pronounced gametocytocidal properties. METHODS: Three days of treatment with artesunate (AS)-amodiaquine (AQ) combined with MB was compared with AS-AQ treatment in a randomized controlled phase IIb study; the study included 221 children aged 6-59 months with uncomplicated falciparum malaria in Burkina Faso. The primary end point was gametocyte prevalence during follow-up, as determined by microscopy and real-time quantitative nucleic acid sequence-based amplification (QT-NASBA). RESULTS: The gametocyte prevalence of Plasmodium falciparum at baseline was 3.6% (microscopy) and 97% (QT-NASBA). It was significantly lower in the AS-AQ-MB than in the AS-AQ group on day 7 of follow-up (microscopy, 1.2% vs 8.9% [P < .05]; QT-NASBA, 36.7% vs 63.3% [P < .001]). Hemoglobin values were significantly lower in the AS-AQ-MB group than in the AS-AQ group at days 2 and 7 of follow-up. Vomiting of the study medication occurred significantly more frequently in the AS-AQ-MB group. CONCLUSIONS: The combination of MB with an artemisinin-based combination therapy has been confirmed to be effective against the gametocytes of P. falciparum. MB-based combinations need to be compared with primaquine-based combinations, preferably using MB in an improved pediatric formulation. Clinical Trials Registration: NCT01407887.

Marked differences in the prevalence of chloroquine resistance between urban and rural communities in Burkina Faso.

BACKGROUND: Chloroquine (CQ) resistance has reached high levels in Africa in recent years. Little is known about variations of resistance between urban and rural areas. OBJECTIVES: To compare the rates of in vivo resistance to CQ and the prevalences of the main molecular marker for CQ resistance among young children from urban and rural areas in Burkina Faso. METHODS: The current analysis used the frame of a randomized controlled trial (ISRCTN27290841) on the combination CQ-methylene blue (MB) (n=177) compared to CQ alone (n=45) in young children with uncomplicated malaria. We examined clinical and parasitological failure rates as well as the prevalence of the Plasmodium falciparum chloroquine resistance transporter gene (pfcrt) T76 mutation. RESULTS: Clinical and parasitological failure rates of CQ-MB differed significantly between urban (70%) and rural areas (29%, p<0.0001). Likewise, CQ failure rates were higher in the urban setting. Matching this pattern, pfcrt T76 was more frequently seen among parasite strains from urban areas (81%) when compared to rural ones (64%, p=0.01). In the presence of parasites exhibiting pfcrt T76, the odds of overall clinical failure were increased to 2.6-fold ([1.33, 5.16], p(LR)=0.005). CQ was detected at baseline in 21% and 2% of children from the urban and the rural study area, respectively (p(Chi)=0.002). CONCLUSION: Even within circumscribed geographical areas, CQ efficacy can vary dramatically. The differences in the prevalence of pfcrt T76 and in CQ failure rates are probably explained by a higher drug pressure in the urban area compared to the rural study area. This finding has important implications for national malaria policies.

Methylene blue for malaria in Africa: results from a dose-finding study in combination with chloroquine.

The development of safe, effective and affordable drug combinations against malaria in Africa is a public health priority. Methylene blue (MB) has a similar mode of action as chloroquine (CQ) and has moreover been shown to selectively inhibit the Plasmodium falciparum glutathione reductase. In 2004, an uncontrolled dose-finding study on the combination MB-CQ was performed in 435 young children with uncomplicated falciparum malaria in Burkina Faso (CQ monotherapy had a > 50% clinical failure rate in this area in 2003). Three serious adverse events (SAE) occurred of which one was probably attributable to the study medication. In the per protocol safety analysis, there were no dose specific effects. The overall clinical and parasitological failure rates by day 14 were 10% [95% CI (7.5%, 14.0%)] and 24% [95% CI (19.4%, 28.3%)], respectively. MB appears to have efficacy against malaria, but the combination of CQ-MB is clearly not effective in the treatment of malaria in Africa.

Safety of the methylene blue plus chloroquine combination in the treatment of uncomplicated falciparum malaria in young children of Burkina Faso [ISRCTN27290841].

BACKGROUND: Safe, effective and affordable drug combinations against falciparum malaria are urgently needed for the poor populations in malaria endemic countries. Methylene blue (MB) combined with chloroquine (CQ) has been considered as one promising new regimen. OBJECTIVES: The primary objective of this study was to evaluate the safety of CQ-MB in African children with uncomplicated falciparum malaria. Secondary objectives were to assess the efficacy and the acceptance of CQ-MB in a rural population of West Africa. METHODS: In this hospital-based randomized controlled trial, 226 children (6-59 months) with uncomplicated falciparum malaria were treated in Burkina Faso. The children were 4:1 randomized to CQ-MB (n = 181; 25 mg/kg CQ and 12 mg/kg MB over three days) or CQ (n = 45; 25 mg/kg over three days) respectively. The primary outcome was the incidence of severe haemolysis or other serious adverse events (SAEs). Efficacy outcomes were defined according to the WHO 2003 classification system. Patients were hospitalized for four days and followed up until day 14. RESULTS: No differences in the incidence of SAEs and other adverse events were observed between children treated with CQ-MB (including 24 cases of G6PD deficiency) compared to children treated with CQ. There was no case of severe haemolysis and also no significant difference in mean haemoglobin between study groups. Treatment failure rates were 53.7% (95% CI [37.4%; 69.3%]) in the CQ group compared to 44.0% (95% CI [36.3%; 51.9%]) in the CQ-MB group. CONCLUSION: MB is safe for the treatment of uncomplicated falciparum malaria, even in G6PD deficient African children. However, the efficacy of the CQ-MB combination has not been sufficient at the MB dose used in this study. Future studies need to assess the efficacy of MB at higher doses and in combination with appropriate partner drugs.

Strong gametocytocidal effect of methylene blue-based combination therapy against falciparum malaria: a randomised controlled trial.

BACKGROUND: With the availability of new preventive and curative interventions, global malaria control has been strengthened significantly in recent years. Drugs effective in reducing malaria gametocytaemia might contribute to local elimination and possible long-term eradication. We here report on the effects of methylene blue (MB)-based malaria combination therapy on gametocytaemia during a randomised-controlled trial in Burkina Faso. METHODS: An open-label randomised controlled phase II study in 180 children aged 6-10 years with uncomplicated falciparum malaria was conducted in Nouna, north-western Burkina Faso. Children were randomised to MB-artesunate (AS), MB-amodiaquine (AQ), and AS-AQ (local standard of care). Overall follow-up was for 28 days, follow-up for gametocytaemia was for 14 days. FINDINGS: The treatment groups were similar in baseline characteristics and there was only one loss to follow-up. Compared to AS-AQ, both MB-containing regimens were associated with significantly reduced gametocyte carrier rates during follow-up days 3, 7, and 14. This effect was seen both in patients with and without P. falciparum gametocytaemia at baseline. INTERPRETATION: MB reveals pronounced gametocytocidal activity which appears to act against both existing and developing P. falciparum gametocytes. MB-based combination therapy thus has the potential to reduce transmission of P. falciparum malaria in endemic regions, which has important implications for future elimination and eradication strategies. TRIAL REGISTRATION: (ClinicalTrials.gov) NCT00354380.

Diagnosis of red cell G6PD deficiency in rural Burkina Faso: comparison of a rapid fluorescent enzyme test on filter paper with polymerase chain reaction based genotyping.

Glucose-6-phosphate dehydrogenase (G6PD) deficient individuals are at increased risk of developing haemolysis following treatment with various antimalarial drugs. Reliable field tests for G6PD deficiency are thus needed in chemotherapy studies and their validity has to be assessed. In two phase II clinical trials on methylene blue (MB) antimalarial therapy in rural Burkina Faso, paediatric and adult participants were tested for G6PD deficiency. The results of a haemoglobin-adjusted nicotinamide adenine dinucleotide phosphate (NADPH) fluorescence test on paper (NFP test) were compared with polymerase chain reaction (PCR)-based G6PD genotyping also using blood samples on filter papers. This is the first study comparing sensitivity and specificity of the two methods. There was good agreement between the NFP test results and the PCR findings. The estimate of the sensitivity of the NFP test was 98.2% (95.8-99.6%) and the specificity was 97.1% (94.2-99.2%). In conclusion, the NFP assay is a reliable and inexpensive method for large-scale G6PD deficiency screening in rural West Africa.