Randomized comparison of amodiaquine plus sulfadoxine-pyrimethamine, artemether-lumefantrine, and dihydroartemisinin-piperaquine for the treatment of uncomplicated Plasmodium falciparum malaria in Burkina Faso.

BACKGROUND: Combination antimalarial therapy is advocated to improve treatment efficacy and limit selection of drug-resistant parasites. We compared the efficacies of 3 combination regimens in Bobo-Dioulasso, Burkina Faso: amodiaquine plus sulfadoxine-pyrimethamine, which was recently shown to be highly efficacious at this site; artemether-lumefantrine, the new national first-line antimalarial regimen; and dihydroartemisinin-piperaquine (DP), a newer regimen. METHODS: We enrolled 559 patients >or=6 months of age with uncomplicated Plasmodium falciparum malaria and randomized them to the 3 regimens. We analyzed the risk of recurrent parasitemia by day 28 and day 42, both unadjusted and adjusted by PCR methods to distinguish recrudescence and new infection. RESULTS: Complete data were available for 517 (92.5%) of the enrolled subjects. Early treatment failures occurred in 5 patients treated with amodiaquine plus sulfadoxine-pyrimethamine and in 2 patients each treated with the other regimens. The day 28 risk of recurrent parasitemia, unadjusted by genotyping, was significantly higher for patients receiving artemether-lumefantrine than for patients receiving amodiaquine plus sulfadoxine-pyrimethamine (20.1% vs. 6.2%; risk difference, 13.8%; 95% confidence interval, 7.0%-20.7%) or dihydroartemisinin-piperaquine (20.1% vs. 2.2%; risk difference, 17.9%; 95% confidence interval, 11.6%-24.1%). Similar differences were seen for children <5 years of age (54% of the study population) and when outcomes were extended to 42 days. Significant differences were not seen between outcomes for patients receiving amodiaquine plus sulfadoxine-pyrimethamine and outcomes for those receiving dihydroartemisinin-piperaquine. Recrudescences were uncommon (occurring in <5% of patients) in all treatment groups. No serious adverse events were noted. CONCLUSIONS: All regimens were highly efficacious in clearing infection, but considering the risks of recurrent malaria after therapy, the amodiaquine plus sulfadoxine-pyrimethamine and dihydroartemisinin-piperaquine regimens were more efficacious than the artemether-lumefantrine regimen (the new national regimen in Burkina Faso) for the treatment of uncomplicated P. falciparum malaria.     

Efficacy of atovaquone-proguanil for treatment of acute multidrug-resistant Plasmodium falciparum malaria in Thailand

A combination of atovaquone-proguanil (Malarone); GlaxoSmithKline, Research Triangle Park, NC) was previously shown to be highly effective in the treatment of uncomplicated Plasmodium falciparum malaria. However, there are only limited recent efficacy data, particularly from regions of multidrug resistance. In this study, we examined the efficacy of atovaquone-proguanil for the treatment of uncomplicated P. falciparum malaria on the Thailand-Myanmar border. Patients were given directly observed atovaquone-proguanil (1,000 mg/400 mg) once a day for three days and followed-up for four weeks in a non-transmission area. Of 140 eligible patients enrolled in this open-label study, 97.8% (95% confidence interval = 95.4-100%) responded to therapy and remained clear of parasitemia at follow-up. Mean parasite clearance time was 41.9 hours and mean fever clearance time was 37.1 hours. On the basis of genotyping, three cases of treatment failure were identified (1 RIII and 2 RI). These data indicate that atovaquone-proguanil remains highly efficacious for the treatment of multidrug-resistant P. falciparum malaria in Thailand.     

Pharmacokinetic study of artemether-lumefantrine given once daily for the treatment of uncomplicated multidrug-resistant falciparum malaria

BACKGROUND: Adherence to antimalarial drug regimens is improved by simple dosing. If the fixed antimalarial drug combination artemether-lumefantrine (AL) could be given once daily, this should improve adherence and thus effectiveness and lower the risk of selecting for resistance. METHODS: In an open randomized study, 43 patients with uncomplicated falciparum malaria were given equivalent doses of AL with 200 ml flavoured milk either as the conventional twice-daily regimen or as a single daily dose for 3 days. The primary end point was a comparison of the areas under the plasma lumefantrine concentration-time curves (AUC). Secondary end points were the day 42 polymerase chain reaction (PCR)-adjusted cure rates and the tolerability profiles. RESULTS: Lumefantrine pharmacokinetic profiles were obtained for 36 patients. The AUC((0-->infinity)) of the once-daily regimen was 30% lower than that in the conventional regimen (P = 0.011) with a median (range) value of 306 (114-5781) microg/ml h, compared with 432 (308-992) microg/ml h. There was no significant difference in the peak plasma concentrations reached. PCR-adjusted cure rate estimates at day 42 of follow-up were 94% (95% CI: 84-100) in the six-dose arm and 85% (70-100) in the three-dose arm (P = 0.3). CONCLUSION: Artemether-lumefantrine efficacy is reduced by once-daily dosing, because absorption of lumefantrine is dose limited. At currently recommended doses, this antimalarial should be given twice daily in a 3-day regimen, with food containing fat.     

A randomized open study to assess the efficacy and tolerability of dihydroartemisinin-piperaquine for the treatment of uncomplicated falciparum malaria in Cambodia

OBJECTIVES: To compare the efficacy and tolerability of dihydroartemisinin-piperaquine (DHA-PQP) with that of a 3-day regimen of mefloquine and artesunate (MAS3) for the treatment of uncomplicated falciparum malaria in Cambodia. METHOD: Randomized open-label non-inferiority study over 64 days. RESULTS: Four hundred and sixty-four patients were included in the study. The polymerase chain reaction genotyping-adjusted cure rates on day 63 were 97.5% (95% confidence interval, CI, 93.8-99.3) for DHA-PQP and 97.5% (95% CI, 93.8-99.3) for MAS3, P = 1. There were no serious adverse events, but significantly more episodes of vomiting (P = 0.03), dizziness (P = 0.002), palpitations (P = 0.04), and sleep disorders (P = 0.03) reported in the MAS3 treatment group, consistent with the side-effect profile of mefloquine. CONCLUSIONS: DHA-PQP was as efficacious as MAS3, but much better tolerated, making it more appropriate for use in a routine programme setting. This highly efficacious, safe and more affordable fixed-dose combination could become the treatment of choice for Plasmodium falciparum malaria in Cambodia.     

Efficacy of Artequick versus artesunate-mefloquine in the treatment of acute uncomplicated falciparum malaria in Thailand

To determine the efficacy, safety and tolerability of an alternative short-course, artemisinin-based combination therapy for acute uncomplicated Plasmodium falciparum malaria, we compared Artequick--a fixed-dosed combination of artemisinin (80 mg), piperaquine (400 mg), and primaquine (4 mg), per tablet--with a standard regimen of artesunate-mefloquine. A total of 130 patients were randomly assigned to treatment with an orally administered, once-daily, 3-day regimen of either Artequick (Group A: 3.2 mg/Kg/day of artemisinin, 16 mg/Kg/day of piperaquine, and 0.16 mg/Kg/day of primaquine) or artesunate-mefloquine (Group B: artesunate, 4 mg/Kg/day, with mefloquine, 8 mg/Kg/day). Patients receiving each regimen had a rapid clinical and parasitological response. All treatments were well tolerated, and no serious adverse effects occurred. No significant differences were found in fever- and parasite-clearance times between the two study groups. The 28-day cure rates were similarly high, at 98.5% and 100%, in groups A and B, respectively. We conclude that Artequick was as effective and well tolerated as artesunate-mefloquine and could be used as an alternative treatment for multidrug-resistant Plasmodium falciparum malaria in Southeast Asia.     

Monitoring the therapeutic efficacy of antimalarials against uncomplicated falciparum malaria in Thailand

Increasing antimalarial drug-resistance is an important problem in Thailand. The results of monitoring the antimalarial efficacy are used in decision-making about using antimalarials to treat uncomplicated falciparum malaria in Thailand. In 2002, 552 patients with uncomplicated malaria were treated according to the Thai National Drug Policy, with mefloquine 25 mg/kg plus artesunate 12 mg/kg and primaquine 30 mg in divided doses for 2 days in high-mefloquine-resistant areas; mefloquine 15 mg/kg plus primaquine 30 mg in non- or low-mefloquine-resistant areas; mefloquine 15 mg/kg plus artesunate 12 mg/kg and primaquine 30 mg in divided doses for 2 days or Coartem (6-dose regimen for adult contains 480 mg artemether and 2880 mg lumefantrine) plus primaquine 30 mg given over 3 days in moderate-mefloquine-resistant areas. The study shows that mefloquine, artesunate plus mefloquine, and artemether plus lumefantrine are effective in the treatment of uncomplicated malaria in most areas of Thailand except for Ranong and Kanchanaburi, where the first-line treatment regimen should be revised.     

An open label randomized comparison of mefloquine-artesunate as separate tablets vs. a new co-formulated combination for the treatment of uncomplicated multidrug-resistant falciparum malaria in Thailand

BACKGROUND: Delivering drugs in a fixed combination is essential to the success of the strategy of artemisinin-based combination therapy. This prevents one drug being taken without the protection of the other, reducing the chance of emergence and spread of drug resistant strains of Plasmodium falciparum. A lower tablet burden should also facilitate adherence to treatment. A new fixed combination of mefloquine plus artesunate has been developed. This was compared with the conventional regimen of separate tablets for the treatment of uncomplicated multidrug-resistant falciparum malaria. METHODS: On the north-western border of Thailand 500 adults and children with uncomplicated falciparum malaria were randomized to receive either the new fixed combination or separate tablets. They were followed up weekly for 63 days. RESULTS: The day 63 polymerase chain reaction-adjusted cure rates were 91.9% (95% CI 88.2-95.6) in the fixed combination group and 89.2% (85.0-93.4) in the loose tablets group (P=0.3). There was a lower incidence of early vomiting in the group receiving the fixed combination. CONCLUSION: This new fixed combination of mefloquine and artesunate was efficacious, well tolerated and convenient to administer.     

Randomized comparison of chloroquine and amodiaquine in the treatment of acute, uncomplicated, Plasmodium falciparum malaria in children.

The increasing resistance of Plasmodium falciparum to chloroquine (CQ) has created an urgent need for the evaluation of alternative, effective, safe, cheap, readily available and affordable antimalarial treatments. In the present study, the efficacy of amodiaquine (AQ) in the treatment of acute, symptomatic, uncomplicated, P. falciparum malaria was compared with that of CQ, each drug being given at 10 mg/kg per day for 3 days (days 0, 1 and 2). The 210 subjects (104 given AQ and 106 CQ) were Nigerian children aged 5 months-12 years. Fever-clearance times (FCT), parasite densities on days 1-4 and parasite-clearance times (PCT) were all significantly lower with AQ than with CQ. Mean (S.D.) PCT, for example, were 2.6 (0.8) days with AQ and 3.0 (1.0) days with CQ (P = 0.001). The cure rates obtained on days 14, 21 and 28 - 98.1% v. 79.3% (P =0.000), 97.1% v. 64.2% (P = 0.00001) and 95.2% v. 58.5% (P = 0.0000000) with AQ and CQ, respectively - were all also significantly higher with AQ. All but two of the 20 subjects who were considered CQ-treatment failures by day 14 (i.e. two RIII, two RII and 16 RI) responded to subsequent treatment with AQ, with PCT (but not FCT) significantly shorter than during their initial treatment with CQ. In siblings in whom there was clustering of infections, the cure rates were 100% with AQ (N =12) and 63.6% with CQ (N = 11; P = 0.03). Adverse reactions to CQ and AQ were similar and tolerable: pruritus in 10 and 11 children in the AQ and CQ groups, respectively, and gastro-intestinal disturbances which occurred in three children from each group. Haematological parameters were not adversely affected by either drug. At least in the setting of the present study, AQ appears more effective than CQ, effective against CQ-resistant infections, and well tolerated by children with acute, uncomplicated, P. falciparum malaria. It may therefore be useful as an alternative to CQ in areas of CQ resistance.     

Oral clindamycin in the treatment of acute uncomplicated falciparum malaria

Clinical trials on oral clindamycin as an antimalarial in hospitalized patients and residents of endemic communities were conducted in the Philippines between May 1984 and December 1985. Seven and 9 qualified subjects in hospital were treated with 300 mg (regimen A) and 600 mg (regimen B) respectively, twice daily for 5 days. Eighteen patients seen at a rural health unit were given the lower dosage. On the basis of the 28-day extended in vivo test of WHO, P. falciparum in all but one patient showed susceptibility to the drug as a blood schizontocide hence, the clinical cure of malaria. Side effects were few and self-limiting. Ten other patients on regimen A were cured within the 7- and/or 28-day extended test period. Clindamycin per se is currently one of the few alternatives in the treatment of clinically moderate drug-resistant malaria.     

High-dose mefloquine in the treatment of multidrug-resistant falciparum malaria.

The therapeutic efficacy and toxicity of a high-dose (25 mg/kg) mefloquine regimen (M25) and the currently recommended regimen of 15 mg/kg (M15) were compared in 199 patients with acute falciparum malaria in an area with deteriorating multidrug resistance on the Thai-Burmese border. The clinical and parasitologic responses were significantly more rapid with M25. The incidence of treatment failures by day 7-9 was 7% for M15 and 1% for M25 (P = .03) and had increased to 40% and 9%, respectively, by day 28 (P < .0001). Overall failure rates were highest in children (P = .02). Parasite clearance times were a good predictor of the therapeutic response; all patients with parasitemia persisting > 5 days after treatment experienced subsequent recrudescence. Side effects were dose-related and included dizziness, anorexia, nausea, vomiting, and fatigue. Although vomiting < 1 h after treatment was more likely in young children, children overall tolerated mefloquine better than adults, and men better than women. The optimum treatment dose of mefloquine in this area is 25 mg/kg.     

Proguanil plus sulfamethoxazole in the treatment of uncomplicated Plasmodium falciparum malaria

In a malaria endemic area of Brazil where P. falciparum is highly resistant to chloroquine and Fansidar, we conducted an in vivo study to evaluate the therapeutic response of proguanil plus sulfametoxazole against Plasmodium falciparum malaria. Twenty-five adult subjects with uncomplicated P. falciparum malaria received supervised drug administration and were followed for 28 days in an inpatient hospital or in a malaria free-transmission area. The therapeutic regimen was proguanil 100 mg BID plus sulfamethoxazole 1,000 mg BID for 7 days. Of those who took all medications (n=21), 17 (81%) were cured. Recrudescent parasitemia during follow-up occurred in four (19%) patients on days 14, 19, 20 and 21 after beginning of treatment. The remaining four (16%) subjects did not complete their therapeutic regimen because the incidence of side effects. Considering the shortage of falciparum malaria therapeutic options and the urgent need for new regimens to deal with the spread of drug resistant P. falciparum, one might consider the study results as a lead to study analogous compounds, hopefully with fewer adverse reactions.     

Efficacy of artemether-lumefantrine for the treatment of uncomplicated falciparum malaria in northwest Cambodia

OBJECTIVE: To determine the efficacy of artemether-lumefantrine malaria treatment, as an alternative to artesunate + mefloquine, which is becoming ineffective in some areas of the Thai-Cambodian border. METHODS: Two studies were conducted to monitor the efficacy of artemether-lumefantrine in Sampov Lun referral hospital, Battambang Province, in 2002 and 2003, and one study was conducted to assess the efficacy of mefloquine + artesunate in 2003 for comparison. The studies were performed according to the WHO standardized protocol with a follow-up of 28 days. The therapeutic efficacy tests were complemented with in vitro tests and in 2003, with the measurement of lumefantrine plasma concentration at day 7 for the patients treated with artemether-lumefantrine. RESULTS: A total of 190 patients were included: 55 were treated with artemether-lumefantrine in 2002 (AL2002), 80 with artemether-lumefantrine and food supplementation in 2003 (AL2003) and 55 with artesunate + mefloquine in 2003 (AM2003). With the per-protocol analysis, the cure rate was 71.1% in study AL2002, 86.5% in study AL2003 and 92.4% in study AM2003. All the data were PCR corrected. The artemether-lumefantrine cure rate was unexpectedly low in 2002, but it increased with food supplementation in 2003. There was a significant difference (P = 0.02) in lumefantrine plasma concentrations between adequate clinical and parasitological responses and treatment failure cases. In vitro susceptibility to lumefantrine was reduced for isolates sampled from patients presenting with treatment failure, but the difference was not statistically different from isolates sampled from patients who were successfully treated. CONCLUSION: Treatment failure cases of artemether-lumefantrine are most probably because of low levels of lumefantrine blood concentration. Further investigations are necessary to determine whether resistance of Plasmodium falciparum isolates to lumefantrine is present in the region.     

In vivo sensitivity monitoring of mefloquine monotherapy and artesunate-mefloquine combinations for the treatment of uncomplicated falciparum malaria in Thailand in 2003

OBJECTIVE: To monitor the efficacy of anti-malarial treatments in Thailand. METHOD: A 28-day in vivo study in nine provinces along international borders in 2003. The first group comprised 164 patients from four provinces: Mae Hong Son, Chiang Mai, Ratchaburi and Ubon Ratchathani. These patients received 15 mg/kg mefloquine as a single dose. The second group, 58 patients from Kanchanaburi, were treated with 15 mg/kg mefloquine plus artesunate (12 mg/kg). The third group, 196 patients from provinces with high-level mefloquine resistance (Tak, Ranong, Chanthaburi and Trat), received 25 mg/kg of mefloquine plus 12 mg/kg artesunate. In all arms, follow-up blood smears were scheduled for days 1, 2, 3, 7, 14, 21 and 28. All patients tolerated the regimens well. RESULTS: The percentage of adequate clinical and parasitological response to mefloquine monotherapy was 62.0% in Mae Hong Son, 75.0% in Chiang Mai, 94.0% in Ratchaburi and 89.7% in Ubon Ratchathani. In Kanchanaburi, the percentage of adequate clinical and parasitological response to the artesunate-mefloquine combination was 94.2%. In the third group, this response exceeded 90%, except in Trat, where it was only 78.6% (44 patients). CONCLUSION: Mefloquine monotherapy must urgently be replaced in Mae Hong Son and Chiang Mai. The markedly reduced efficacy of the artesunate-mefloquine combination used in Trat raises questions about the future of this therapy on the southeastern border of Thailand with Cambodia. It is very worrying because no practical and affordable alternative is yet available.     

An open randomized clinical trial of Artecom vs artesunate-mefloquine in the treatment of acute uncomplicated falciparum malaria in Thailand

The efficacy and safety of Artecom were assessed in an open randomized trial in adults presenting with acute, uncomplicated Plasmodium falciparum malaria in Thailand. Three hundred and fifty-two patients were randomly enroled at the ratio of 2:1 into group A:B and received Artecom (group A) and the standard combination of artesunate and mefloquine (group B) respectively. All patients had rapid initial clinical and parasitological responses. There were no significant differences in fever clearance time and parasite clearance time between the two groups. The 28-day cure rates were high as 97% in both groups. Artecom was effective and well-tolerated as artesunate-mefloquine, the current treatment in this area of multidrug-resistant P. falciparum malaria.     

Pyrimethamine-sulfadoxine treatment of uncomplicated Plasmodium falciparum malaria in Lao PDR

A 28-day in vivo treatment trial to evaluate the efficacy of pyrimethamine/sulfadoxine (Fansidar, PS) was conducted in 21 Lao patients with uncomplicated Plasmodium falciparum malaria. Sixteen patients (76%) were completely cured with PS without any reappearance of asexual stage parasitemia during the follow-up examination. On the other hand, 5 patients (24%) failed to respond to this trial medication, resulting in recrudescence of asexual stage P. falciparum malaria. PS resistance resulted in higher prevalence of post-treatment gametocytemia, 25% gametocyte carriers among PS sensitive cases versus 75% of the resistant cases. These findings suggest that although the level of PS resistance is still valid for treatment of malaria in the study area of Lao PDR, post-treatment induction of gametocytemia among resistant cases may result an increase in transmission rate of PS resistant falciparum malaria.     

Pituitary-adrenal function in uncomplicated falciparum malaria

To investigate pituitary-adrenal function in acute uncomplicated falciparum malaria, we performed an overnight dexamethasone suppression test in 13 Vietnamese adults with acute malaria and 6 healthy controls. After blood samples were taken for serum cortisol and plasma ACTH at 23.00 hours on the admission day, 1 mg dexamethasone was given and further samples were taken at 08.00, 16.00 and 23.00 hours the next day. The patients received conventional antimalarial and supportive treatment. Baseline plasma ACTH concentrations in the patients [3.9 (0.2-41.2) pmol/l] and controls [3.4 (1.1-4.3) pmol/l] were similar (p=0.51), and exhibited a similar fall after dexamethasone to 0.6 (0.2-2.5) and 0.9 (0.7-1.6) pmol/l at 08.00 hours respectively (p<0.03 vs 23.00 hour values). Serum cortisol levels before dexamethasone were higher in the patients than in the controls [456 (102-821) vs 145 (64-183) nmol/l respectively; p=0.007] and the overnight fall was less in the patients [208 (26-340) and 23 (15-46) nmol/l at 08.00 hours respectively; p<0.001 vs 23.00 hour values and between groups]. Between 08.00 and 23.00 hours, plasma ACTH and serum cortisol remained suppressed in the controls. In the patients, the serum cortisol continued to fall progressively towards control values. These data suggest that there is a raised set point for cortisol inhibition of ACTH secretion but normal corticotrophin responsiveness to dexamethasone in uncomplicated malaria. A raised serum cortisol after dexamethasone in the patients might reflect the combination of a prolonged cortisol half-life and the stimulatory effects of cytokines on the adrenal cortex, with a consequent protective effect against complications such as hypoglycemia.     

An open, randomized comparison of artesunate plus mefloquine vs. dihydroartemisinin-piperaquine for the treatment of uncomplicated Plasmodium falciparum malaria in the Lao People's Democratic Republic (Laos)

OBJECTIVE: To determine the efficacy and safety of oral dihydroartemisinin-piperaquine (DP, Artekin) in the treatment of uncomplicated Plasmodium falciparum malaria in southern Laos. METHODS: An open, randomized clinical trial of oral artesunate-mefloquine (AM) vs. DP in 220 patients with acute uncomplicated falciparum malaria in Savannakhet Province, Laos. RESULTS: The 42-day cure rates (95% CI), as determined by survival analysis and adjusted for reinfection, were excellent and similar for the two groups [99 (94-100)% and 100 (100-100)% for AM and DP, respectively]. The median (range) fever and parasite clearance times for the AM and DP groups were also similar [20 (4-63) h and 2 (1-4) days vs. 20 (7-57) and 2 (1-4) days, logrank P = 0.4 and 0.17, respectively]. There were more patients with at least one potential side effect following treatment in the AM group when compared with the DP group [64/110 (58%) vs. 48/110 (44%), respectively, P = 0.031]. CONCLUSION: Dihydroartemisinin-piperaquine did not have superior efficacy to AM for the treatment of uncomplicated falciparum malaria in Laos but was associated with fewer adverse effects.     

A randomized clinical trial of combinations of artesunate and azithromycin for treatment of uncomplicated Plasmodium falciparum malaria in Thailand.

Recently, a combination of artesunate and mefloquine has proved effective, although is contraindicated in early pregnancy and young children. Azithromycin, a widely used antibiotic and has antimalarial effects, replace mefloquine as a new alternative antimalarial regimen. Two hundred and two uncomplicated falciparum malaria patients were randomly assigned to 1 of 3 regimens. Patients in group I (n = 68) received artesunate 200 mg once daily for 3 days, group II (n = 67) received artesunate 200 mg together with mefloquine 10 mg/kg on the first 2 days and artesunate 200 mg together with mefloquine 5 mg/kg on the third day, and group III (n = 67) received artesunate 200 mg together with azithromycin 50 mg once daily for 3 days. The 28 day cure rates were 44, 98 and 56%, respectively. The median time to recrudescence was significantly longer in group III. In conclusion, a combination of artesunate and azithromycin might be useful in treating children in whom bacterial and malarial infections may be concomitant. However, further work is required in order to enhance its clinical efficacy.