Randomized Comparison of Artesunate and Quinine in the Treatment of Severe Falciparum Malaria

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1 MAJOR ARTICLE Randomized Comparison of Artesunate and Quinine in the Treatment of Severe Falciparum Malaria Paul N. Newton, 1,5 Brian J. Angus, 1,5 Wirongrong Chierakul, 1 Arjen Dondorp, 1,5 Ronatrai Ruangveerayuth, 4 Kamolrat Silamut, 1 Pramote Teerapong, 2 Yupin Suputtamongkol, 3 Sornchai Looareesuwan, 1 and Nicholas J. White 1,5 1 Faculty of Tropical Medicine and 2 Department of Pharmacology, Mahidol University, and 3 Department of Medicine, Siriraj Hospital, Bangkok, and 4 Mae Sot Hospital, Mae Sot, Tak, Thailand; and 5 Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, John Radcliffe Hospital, Oxford, United Kingdom A randomized, open-label comparison of artesunate and quinine was conducted in 113 adults with clinically severe falciparum malaria in western Thailand. Mortality was 12% with artesunate and 22% with quinine treatment (relative risk, 0.53; 95% confidence interval, ; P p.22). Multiple logistic regression analysis found admission plasma lactate level, Glasgow Coma Scale score, and total serum bilirubin level to be independent risk factors for death. Coma recovery and times to normalize plasma lactate levels were similar, but the parasite clearance time was much shorter among artesunate-treated patients ( P p.019). Fewer patients became hypoglycemic during artesunate therapy (10%) than during quinine therapy (28%) ( P p.03). Artesunate is at least as effective as quinine in the treatment of adults with severe malaria. Larger trials are required to determine whether mortality is reduced among patients treated with artesunate. Although many treatment trials have been conducted, no interventions have been unequivocally shown to reduce the high mortality (12% 22%) associated with severe falciparum malaria. The conventional therapy is parenteral quinine, but this has a narrow therapeutic ratio, is associated with hyperinsulinemic hypoglycemia, and requires either repeated constant-rate infusions or painful intramuscular injections [1 3]. Although there is some evidence that the efficacy of quinine is decreasing in Southeast Asia, in terms of parasite and fever clearance and coma recovery times Received 24 July 2002; accepted 12 February 2003; electronically published 23 June Financial support: Wellcome Trust Mahidol University Oxford Tropical Medicine Research Programme (funded by the Wellcome Trust of Great Britain). Reprints or correspondence: Dr. Nicholas J. White, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Rd., Bangkok 10400, Thailand (fnnjw@ diamond.mahidol.ac.th). Clinical Infectious Diseases 2003; 37: by the Infectious Diseases Society of America. All rights reserved /2003/ $15.00 [4 9], there is no evidence that this has translated into an increase in mortality among treated patients. The artemisinin derivatives artesunate and artemether are used widely in Southeast Asia to treat malaria. In combination with other antimalarial drugs used to treat multidrug-resistant falciparum malaria, they augment efficacy, inhibit the emergence of drug resistance, and reduce transmission [10 19]. There are 3 parenteral forms: water-soluble artesunate, which is rapidly hydrolyzed in vivo to the more active dihydroartemisinin (DHA), and the lipid-soluble, intramuscular artemether and arteether, which are absorbed slowly and also converted to DHA [11, 17, 18]. Most studies of severe malaria have evaluated artemether or arteether, rather than artesunate [20 29]. An individual patient data meta-analysis of 8 randomized clinical trials involving patients with severe malaria concluded that parenteral artemether was as effective as quinine in terms of mortality but superior in terms of the number of serious adverse events associated with its use [24, 25]. Artesunate is likely to be superior to artemether in the treatment of Artesunate vs. Quinine in Severe Malaria CID 2003:37 (1 July) 7

2 severe malaria, for 3 reasons. First, artesunate, unlike artemether, can be administered intravenously, and it is absorbed rapidly after intramuscular injection, whereas intramuscular artemether is absorbed erratically [30, 31]. Delay in delivery of a lifesaving drug in severely ill patients is likely to be deleterious. Second, artesunate is more potent: artesunate and DHA have in vitro antimalarial activities that are 2.9 and 4.0 times greater, respectively, than the activity of artemether [32]. Third, although neurotoxicity has not been demonstrated in humans, in animal models, parenteral artemether is more neurotoxic than is parenteral artesunate [33]. We therefore conducted a randomized, open-label trial of artesunate versus quinine in adult patients with severe falciparum malaria that used changes in plasma lactate as the primary end point. This study was a prelude to consideration of a large, multicenter mortality trial. PATIENTS AND METHODS Study site and patients. The present study was conducted during May through July 1994 at Sangklaburi Hospital, Kanchanaburi Province, and during at Mae Sot Hospital, Tak Province, in western Thailand. These hospitals serve a predominantly rural population of Thai farmers and Burmese and Karen migrant workers [15, 19, 29, 34]. Malaria transmission is seasonal and of low intensity [35]. Ethical clearance for the study was obtained from the Ministry of Public Health, Government of Thailand. Patients 15 years old who had been admitted to the hospital with slideconfirmed, single-species Plasmodium falciparum parasitemia Table 1. Distribution of patients enrolled in a study comparing artesunate and quinine for the treatment of malaria in Thailand, by criteria for severe malaria. Criterion of 10.1% were recruited if they or an attending relative provided written informed consent and if they had severe malaria (table 1) [20]. Because the results of some of the laboratory investigations were not immediately available, patients were enrolled in the study on clinical grounds. Pregnant women, patients with contraindications to taking the study drugs, and patients with artesunate, mefloquine, or significant quinine (12g) intake in the previous 24 h were excluded from the study. To demonstrate a reduction from 60% to 30% in the proportion of patients with plasma lactate levels 2 mmol/l at 24 h with 80% power and 95% confidence required that 96 patients be included in the study. Antimalarial treatment. Patients were randomly assigned in blocks of 10 to receive artesunate or quinine. The first group received intravenous artesunate (Guilin No. 2 Pharmaceutical Factory, Guangxi, People s Republic of China; 2.4 mg/kg on entry, followed by 1.2 mg/kg 12 h later and then 1.2 mg/kg/ day). Each 60-mg vial of artesunic acid was dissolved in 1 ml of 5% sodium bicarbonate to form sodium artesunate and then mixed with 5 ml of 5% dextrose. This was injected as a bolus into an indwelling intravenous cannula. When the patient was able to swallow tablets, oral artesunate was administered (12 mg/kg over the course of 7 days). Beginning in 1995, oral artesunate was combined with mefloquine (either 15 mg/kg as a single dose or 25 mg/kg divided into 1 dose of 15 mg/kg initially and 1 dose of 10 mg/kg h later). After a report indicated an increased risk of neuropsychiatric reactions to mefloquine in patients with severe malaria [36], tetracycline (250 mg q6h for 7 days) or doxycycline (100 mg twice daily for 7 days) was substituted. Total (n p 113) Treatment group, no. of patients Artesunate (n p 59) Quinine (n p 54) Glasgow Coma Scale score! Hematocrit!20% with asexual parasitemia 1100,000 parasites/ml Total serum bilirubin level 150 mmol/l with asexual parasitemia 1100,000 parasites/ml Serum creatinine level 1264 mmol/l with urine output!400 ml/24 h Systolic blood pressure!80 mm Hg with cool extremities Asexual parasitemia 110% Plasma lactate level 14 mmol/l Plasma glucose level!2.2 mmol/l Plasma venous bicarbonate level!15 mmol/l P NOTE. Adapted from Hien et al. [20]. Severe malaria was defined by the presence of 1 of the criteria listed. For all variables, there were no significant differences between the artesunate and quinine groups. 8 CID 2003:37 (1 July) Newton et al.

3 Figure 1. Flow chart of patient enrollment and outcomes in a study comparing artesunate and quinine for the treatment of malaria in Thailand The second group received intravenous quinine dihydrochloride (Government Pharmaceutical Organisation, Bangkok, Thailand), 20 mg/kg in 666 ml of normal saline, administered over the course of 4 h. This was followed by 10 mg in 333 ml of normal saline over the course of 2 h, infused 3 times daily. When the patient was able to swallow tablets, oral quinine (10 mg/kg q8h) was substituted, for a total of 7 days of treatment, with additional mefloquine, tetracycline, or doxycycline as described above. The randomization was open. Supportive treatment was in accordance with the 1990 guidelines of the World Health Organization [3]. The investigations performed included complete blood count, serum biochemistry, chest radiography and abdominal ultrasound, diagnostic lumbar puncture for comatose patients, and hemodynamic monitoring. Peritoneal dialysis and, from 1998 on, hemodialysis were available. Intramuscular phenobarbitone (3.5 mg/kg) was administered to unconscious patients as seizure prophylaxis. The antibiotics used to treat complicating infections were ampicillin, gentamicin, cefotaxime, and ceftazidime, which have no important antimalarial activity. Study procedures. At admission, blood samples were obtained to assess hematocrit, parasitemia, and parasite staging [37]; plasma lactate levels; glucose levels; and full biochemistry. Plasma quinine concentrations were estimated by dipstick [38]. Hematocrit and parasite counts were measured at 0, 1, 2, 4, 6, 8, 10, 12, 16, 20, and 24 h and then every 6 h until 6 h after parasite clearance. Samples were obtained for glucose and lactate analysis at 0, 4, 8, 12, 16, 20, and 24 h and then every 6 h. Vital signs (pulse, respiratory rate, blood pressure, axillary temperature, and Glasgow Coma Scale [GCS] score) were measured every 15 min for the first hour, at 2 h, and then every 2 h until 12 h, every 4 h from 12 to 24 h, and every 6 h from 24 h until parasite clearance. Parasite clearance time was defined as the interval between the start of treatment and the time of the first of 2 sequential negative thick films. PC 50 is the time to 50% reduction in parasite density, and PC 90 is the time to 90% reduction in parasite density. These were calculated by log-linear interpolation of the parasite count and time data. Parasite reduction ratios at 24 h (PRR 24 ) and 48 h (PRR 48 ) were defined as the ratio of the parasite count at admission to that at 24 or 48 h [39]. Fever clearance times were measured from the start of antimalarial treatment to the time at which the axillary temperature first dropped below 37.5 C and to the time at which the axillary temperature first dropped below 37.5 C and remained below 37.5 C for 24 h. Coma recovery time (for patients with a GCS score!11 [of 15] on admission) was measured from the start of antimalarial treatment to the time at which the GCS score reached 15. Time to normal plasma lactate level was defined as the interval between the start of treatment and a decrease to!2 mmol/l. Statistical analysis. Analysis was performed by SPSS software (version 8.0). Normally distributed data were compared using Student s t test, and non normally distributed data were compared using the Mann-Whitney U and Wilcoxon signed rank tests. The Bonferroni correction was used for multiple comparisons. Categorical data were compared by x 2 test with Yates correction and Fisher s exact test. Kaplan-Meier plots were de- Artesunate vs. Quinine in Severe Malaria CID 2003:37 (1 July) 9

4 Table 2. Clinical and laboratory details on admission for patients enrolled in a study comparing artesunate and quinine for the treatment of malaria in Thailand. Treatment group Variable All (n p 113) Artesunate (n p 59) Quinine (n p 54) Body weight, mean kg (95% CI) 50.7 ( ) 50.9 ( ) 50.4 ( ).8 No. of male patients/no. of female patients 79/34 39/20 40/14.4 Age, median years (range) 25 (15 66) 25 (15 66) 25 (15 59).6 No. of prior malaria attacks per patient, median (range) 0 (0 20) 0.5 (0 5) 0 (0 20).8 No. of days ill, mean (95% CI) 4.0 ( ) 4.0 ( ) 4.0 ( ).9 No. of patients with seizures a Axillary temperature, mean C (95% CI) 38.5 ( ) 38.3 ( ) 38.7 ( ).1 Pulse, mean beats/min (95% CI) 111 ( ) 112 ( ) 110 ( ).4 Systolic blood pressure, mean mm Hg (95% CI) 107 ( ) 105 ( ) 110 ( ).07 Diastolic blood pressure, mean mm Hg (95% CI) 64 (62 67) 63 (59 67) 66 (63 69).2 Respiratory rate, median breaths/min (range) 30 (18 54) 28 (20 54) 30 (18 48).6 Hepatomegaly, median cm (range) 1 (0 10) 1 (0 10) 1 (0 8).5 Splenomegaly, median cm (range) 0 (0 8) 0 (0 10) 0 (0 10).4 Median Glasgow Coma Scale score (range) 15 (3 15) 15 (3 15) 13 (3 15).04 No. of patients with retinal hemorrhages b Parasitemia, geometric mean parasites/ml (95% CI) c 208,320 (152, ,204) 225,092 (139, ,427) 194,294 (129, ,240).6 Trophozoites and schizonts, median % (range) 7 (0 99) 7 (0 89) 9 (0 99).6 Hematocrit, median % (range) 33.1 ( ) 32.2 ( ) 34.2 ( ).1 Peripheral WBC count, median cells 10 6 /L (range) 8.8 ( ) 8.9 ( ) 8.6 ( ).9 Plasma glucose level, mean mmol/l (95% CI) d 8.5 ( ) 8.2 ( ) 8.4 ( ).8 Plasma lactate level, median mmol/l (range) e 4.3 ( ) 4.8 ( ) 3.8 ( ).4 Serum creatinine level, mmol/l, median (range) f 114 (44 792) 123 (44 792) 110 (53 722).5 Serum urea level, median mmol/l (range) g 10.2 ( ) 11.3 ( ) 8.9 ( ).06 Total serum bilirubin level, median mmol/l (range) h 51 (9 646) 54 (8 646) 54 (11 453).9 Serum bicarbonate level, median mmol/l (range) i 19.5 ( ) 19.0 ( ) 20.0 ( ).9 NOTE. The variables in bold are those identified prospectively as the main variables to be used in the analysis. a Data were available from only 58 patients in the artesunate group. b Data were available from only 92 patients, 47 in the artesunate group and 45 in the quinine group. c No. of asexual parasites/1000 erythrocytes on thin film hematocrit d Normal range, mmol/l. e Normal,!2 mmol/l. f Normal range, mmol/l. g Normal range, mmol/l. h Normal range, 3 17 mmol/l. i Normal range, mmol/l. P termined for primary and secondary variables. Logistic regression models were compared using the likelihood ratio test. RESULTS One hundred thirteen patients were recruited between April 1994 and July 2001 (11 at Sangklaburi and 102 at Mae Sot); 59 were randomly assigned to receive artesunate and 54 were assigned to receive quinine treatment (figure 1 and tables 1 3). The study lasted longer than intended, because the majority of patients admitted with severe malaria had received antimalarial therapy before admission and were therefore ineligible. To avoid treatment delay, patients were recruited and randomized before the results of all laboratory investigations were available. Thirteen patients recruited were subsequently found not to fulfill the entry criteria for severe malaria ( n p 12) or to have very low levels of parasitemia ( n p 1; 132 parasites/ml). Therefore, 100 patients who fulfilled the criteria for severe malaria were studied, 54 of whom received artesunate and 46 of whom received quinine. The data were analyzed primarily by intent-totreat methods ( n p 113) and secondarily for the subset of pa- tients who met the strict definition for severe malaria (n p 100). Some of the patients recruited into this study were also included in studies of pathophysiology reported elsewhere [40 42]. The study population was predominantly Burmese and Karen (77%), with Thai (21%) and Hmong (2%) ethnic groups. Clinical and laboratory parameters on admission, including 10 CID 2003:37 (1 July) Newton et al.

5 variables considered a priori to be key prognostic indicators in adults, did not differ significantly between the quinine and artesunate groups for all patients and for the subset of patients with severe malaria ( P 1.1; tables 1 and 2). The median admission GCS score was lower in the quinine group; 39% of the patients in that group had cerebral malaria, compared with 24% in the artesunate group ( P p.06). The median number of criteria for severe malaria met per patient was 2 in both groups (range, 1 5 in the quinine group and 1 6 in the artesunate group; P p.9). Concurrent conditions were excessive alcohol use (2 patients in the artesunate group and 2 in the quinine group); amphetamine use (2 and 1, respectively); bilateral cataracts (2 and 1); HIV infection (1 and 1); pulmonary tuberculosis (0 and 1); nephrotic syndrome, treated with steroids (0 and 1); positive results of Coombs test for hemolytic anemia, treated with steroids (1 and 0); and mitral or aortic valve disease (3 and 0). Urine quinine concentrations 2.5 mg/ dl were detected by dipstick testing at admission in 6 patients (4 in the quinine group and 2 in the artesunate group; P 1.05). Five patients received intravenous Ringer s lactate solution before recruitment; the plasma lactate results from these patients were excluded from the analysis. Lumbar puncture was performed at admission for 33 patients (29%). The mean opening pressure was 14.6 cm H 2 O (95% CI, cm H 2 O). The mean CSF protein level was 84 mg/dl (95% CI, mg/dl), the mean CSF glucose level was 4.9 Table 3. Treatment regimens for patients enrolled in a study comparing artesunate and quinine for the treatment of malaria in Thailand. Treatment mmol/l (95% CI, mmol/l), and the median WBC count was 7 cells/mm 3 (range, cells/mm 3 ). The median percentage of lymphocytes was 100% (range, 80% 100%). None of the CSF parameters differed significantly between the 2 treatment groups. No patient had coincident bacterial meningitis. The frequency of mechanical ventilatory support was higher in the quinine group than in the artesunate group ( P p.04). Nineteen patients received tetracycline, and 29 received doxycycline, with mean total doses of 113 mg/kg (95% CI, mg/kg) and 28.7 mg/kg (95% CI, mg/kg), respectively. Twenty-one patients received mefloquine at a mean total dose of 24.9 mg of mefloquine base/kg (95% CI, ). Clinical outcome. The overall mortality was 17% (19 of 113 patients; tables 4 and 5). Seven patients in the artesunate group died (12%), and 12 patients in the quinine group died (22%) (relative risk [RR], 0.53; 95% CI, ; P p.22). The causes of death were usually multifactorial (table 5). One of the 13 patients excluded from the final group of 100 also died. This patient presented without evidence of previous antimalarial treatment, with a GCS score of 5, and with parasitemia of only 3 parasites/200 WBCs (120 cells/ml). Despite treatment with artesunate, the patient developed bacterial pneumonia, a spontaneous pneumothorax, and acute respiratory distress syndrome and died after 187 h in the hospital. The survival curves (for all 113 patients) are illustrated in 2 figure 2A ( x p 2.24 and P p.13, by log-rank test; for the 100 All (n p 113) Treatment group Artesunate (n p 59) Quinine (n p 54) Intravenous artesunate, mean mg/kg (95% CI) 6.4 ( ) Oral artesunate, mean mg/kg (95% CI) 5.9 ( ) Total artesunate, mean mg/kg (95% CI) 11.2 ( ) Intravenous quinine, mean mg of salt/kg (95% CI) 94 (76 113) Oral quinine, mean mg of salt/kg (95% CI) 155 ( ) Total quinine, mean mg/kg (95% CI) 209 ( ) No. of intravenous doses, median (range) 5 (2 9) a 6 (2 21) a No. of oral doses, median (range) 6 (1 12) 15 (3 28) Blood transfusion, no. of patients Units of blood transfused per patient, median (range) 0 (0 8) 0 (0 4) 0 (0 8).7 Urinary catheter, no. of patients Furosemide and/or dopamine, no. of patients Central venous access, no. of patients Ventilatory support, no. of patients Renal dialysis, no. of patients Antibiotics, no. of patients Ionotropes, no. of patients P NOTE. Drug doses are in mg/kg of body weight. a Includes a loading dose of twice the maintenance dose. Artesunate vs. Quinine in Severe Malaria CID 2003:37 (1 July) 11

6 Table 4. Outcome measures for treatment of patients enrolled in a study comparing artesunate and quinine for the treatment of malaria in Thailand. Treatment group Variable All (n p 113) Artesunate (n p 59) Quinine (n p 54) Time in hospital, mean days (95% CI) 5.1 ( ) 5.1 ( ) 5.0 ( ).9 Time in ICU, median days (range) 0 (0 3) 0 (0 3) 0 (0 3).7 Hypoglycemia, no. of patients Seizures after admission, no. of patients Bleeding after admission, no. of patients Sepsis after admission, no. of patients Pulmonary edema, no. of patients Oliguria, no. of patients PCT, mean h (95% CI) a 68.8 ( ) 62.5 ( ) 76.0 ( ).019 Increase in parasitemia between 0 and 6 h, no. of patients Time to PC 50, median h (range) a 9.0 ( ) 9.1 ( ) 8.0 ( ).3 Time to PC 90, median h (range) a 23.3 ( ) 20.5 ( ) 24.7 ( ).08 PRR 24, median (range) a 10.7 ( ) 17.5 ( ) 7.0 ( ).02 PRR 48, median (range) a 789 (2 25,095) 2394 (10 25,095) 586 ( ).03 Minimum hematocrit, mean % (95% CI) 23.3 ( ) 22.4 ( ) 24.2 ( ).2 Change in hematocrit, mean % (95% CI) 27.5 ( ) 26.2 ( ) 28.9 ( ).4 Time to minimum hematocrit, median h (range) 30 (0 120) 30 (0 120) 27 (0 120) 1.0 FCTa, median h (range) a 11 (1 84) 11 (1 83) 13 (1 184).2 FCTb, median h (range) a 50 (3 383) 41 (3 138) 65 (12 383).2 Time to plasma lactate level!2 mmol/l, median h (range) a 14 (1 120) 16 (2 72) 8 (1 120).3 Coma recovery time, median h (range) a 17 (1 188) 17 (1 125) 18 (1 188).6 No. of patients who died/no. who survived through discharge 19/94 7/52 12/42.2 Time to death, median h (range) a 42 (3 408) 48 (29 408) 21 (3 144).02 NOTE. Variables in bold are those identified prospectively as the main variables to be used in the analysis. FCT, fever clearance time; FCTa, interval between the start of antimalarial treatment and the point at which the axillary temperature first dropped below 37.5 C; FCTb, interval between the start of antimalarial treatment and the point at which the axillary temperature first dropped below 37.5 C and remained below 37.5 C for 24 h; ICU, intensive care unit; PCT, parasite clearance time; PC 50, 50% reduction in parasite density; PC 90, 90% reduction in parasite density; PRR, parasite reduction ratio; PRR 24, ratio of parasite count at admission to that at 24 h; PRR 48, ratio of parasite count at admission to that at 48 h. a Data were available from only 91 patients for PCT; from 105, for PC 50 ; from 102, for PC 90 ; from 99, for PRR 24 ; from 65, for PRR 48 ; from 84, for FCTa; from 59, for FCTb; from 50, for time to plasma lactate level!2 mmol/l; from 32, for coma recovery time; and from 19, for time to death. P 2 patients with severe malaria, x p 3.71 and P p.05). The overall median time between the initiation of antimalarial treatment and death was 42 h (range, h). This was significantly shorter for quinine-treated patients (21 h; range, h) than for artesunate-treated patients (48 h; range, h) (P p.02; table 4). Of 9 patients who received a clinical diagnosis of pulmonary edema or acute respiratory distress syndrome, only 1 patient, who had been treated with artesunate, survived. Two patients in each treatment group developed intravenous cannula site infections. The overall median coma recovery time for patients who presented with a GCS score of!15 was 17 h (range, h), and this was not significantly different between the 2 treatment groups. Coma recovery times in those who presented with a GCS score of!11 were not significantly different ( x 2 p 0.09 and P p.5, by Kaplan-Meier plot; figure 2B). Fever clearance 2 times ( x p 0.06 and P p.32, by Kaplan-Meier plot; figure 2C and table 4) and temporal changes in pulse, blood pressure, respiratory rate, and fever did not differ between the 2 treatment groups. Of the 100 patients with strictly defined severe malaria, there were significant differences between the artesunate- and quinine-treated patients in the frequency of hypoglycemia (6 of 54 vs. 15 of 46 patients; RR, 0.34; 95% CI, ; P p 12 CID 2003:37 (1 July) Newton et al.

7 Table 5. Complications and causes of death among patients enrolled in a study comparing artesunate and quinine for the treatment of malaria in Thailand. Outcome, syndrome No. of patients in treatment group Total Artesunate Quinine Death Pulmonary edema/ards 6 3 a 3 Cardiorespiratory arrest Intractable hypotension and oliguria b Hypotension and gastrointestinal tract bleeding Survived through discharge Blackwater fever Ulnar or median nerve palsy Klebsiella species urinary tract infection Pneumonia Herpes zoster NOTE. ARDS, acute respiratory distress syndrome. a Includes 2 patients with spontaneous pneumothoraces and 1 with pneumonia. b Includes 1 patient with severe pneumonia..017), median PRR 48 (2920 [range, ,095] vs. 408 [range, ,386]; P p.027), and frequency of ventilatory support (7 of 54 vs. 16 of 46 patients; P p.016). The applicable subset analysis performed by the Artemether- Quinine Meta-analysis Study Group [25] was also performed on this data set. There were no significant differences in mortality associated with artesunate treatment among male patients, patients with acute renal failure, patients with hypoglycemia, or patients with jaundice ( P 1.1). In a multiple logistic regression analysis of factors present at admission that were potentially associated with death, plasma lactate level, GCS score, serum total bilirubin level, serum creatinine level, and the proportion of trophozoites and schizonts in the admission blood film were each independently associated with death (table 6). The likelihood ratio test identified the proportion of trophozoites and schizonts (OR, 1.036; 95% CI, ; P p.0005) and plasma lactate levels (OR, 1.276; 95% CI, ; P p.0003) as the best model for prediction of a fatal outcome. The addition of primary drug treatment as a variable did not improve the model. Parasitological and hematological outcome. Hematocrit profiles did not differ significantly between the 2 treatment groups (table 4). The parasite clearance time for the artesunatetreated patients (mean, 62.5 h; 95% CI, h) was significantly shorter than that for the quinine-treated patients (mean, 76.0 h; 95% CI, h) ( P p.019; figure 3). The proportion of patients with a parasite count that had risen at 6 h and the median PC 50,PC 90, PRR 24, and PRR 48 did not differ significantly between the 2 groups ( P 1.05). A 41-kg patient who received a high dose of parenteral quinine (29-mg/kg loading dose, followed by 7 intravenous doses of 14 mg/kg) and then 7 doses of oral quinine sulphate (14 mg/kg q8h) and 4 doses of oral doxycycline (2.4 mg/kg) cleared parasitemia at 48 h, but P. falciparum parasitemia reappeared on the fifth day after initiation of treatment, representing an RII treatment failure [43]. Glucose and lactate profiles. Fewer patients became hypoglycemic in the artesunate group (10%) than in the quinine group (28%) (RR, 0.37; 95% CI, ; P p.03). The median time to plasma lactate level 2 mmol/l was 14 h (range, h), and this did not differ significantly between the 2 2 treatment groups ( x p 0.38 and P p.5, by Kaplan-Meier plot; figure 2D and table 4). The proportions of patients with plasma lactate levels 2 mmol/l at 24 h were 32% and 36% in the quinine and artesunate groups, respectively ( P 1.05). Drug-related adverse events. Patients treated with quinine consistently developed cinchonism and had a significantly higher frequency of hypoglycemia. One patient had a probable adverse reaction to artesunate. This patient presented with parasitemia of 31%, a plasma lactate level of 14.5 mmol/l, and a serum bilirubin level of 23 mg/dl and developed a widespread erythematous urticarial rash 17 h after treatment with intravenous artesunate was initiated. No other drugs had been administered. Intravenous quinine was substituted, but the patient died 52 h later with pulmonary edema, oliguria, hypotension, and electromechanical dissociation. This was attributed to severe malaria. DISCUSSION The present study suggests that artesunate is an effective alternative to quinine in the treatment of severe malaria. The Artesunate vs. Quinine in Severe Malaria CID 2003:37 (1 July) 13

8 Figure 2. Kaplan-Meier plots of survival (A), time to normal Glasgow Coma Scale (GCS) score for those with an admission score!11 (B), time to first temperature!37.5 C (C), and time to plasma lactate level!2 mmol/l (D) among subjects included in a study comparing artesunate (dashed lines) and quinine (solid lines) for the treatment of malaria in Thailand. One patient in the artesunate group (data point not shown in A) died 408 h after treatment began. mortality difference in the study was large and in favor of artesunate, but the difference was not statistically significant (this preliminary trial was powered only to detect huge differences in mortality). Among artesunate-treated patients, parasite clearance times were shorter, incidence of posttreatment hypoglycemia was lower, and time to death was longer. The 2 groups did not differ in duration of hospitalization, coma recovery time, and time to normalization of plasma lactate levels. The higher incidence of hypoglycemia in the quinine group was expected, because quinine provides a potent stimulus to insulin secretion [1]. The reason for the higher frequency of ventilatory support in the quinine group is unclear; the 2 treatment groups did not differ in the frequency of pulmonary edema and sepsis or of clinical interventions such as placement of central venous access lines, urinary catheters, and antibiotic use. It has recently been suggested that artesunate has a diuretic effect in patients with severe malaria [44], but there were no significant differences between the treatment groups in the proportion of patients who developed oliguria or pulmonary Table 6. Logistic regression analysis of the association between factors present on admission and death among patients enrolled in a study comparing artesunate and quinine for the treatment of malaria in Thailand. Variable OR (95% CI) P Glasgow Coma Scale score 0.7 ( ).007 Total serum bilirubin level 1.18 ( ).014 Percentage of trophozoites and schizonts 1.03 ( ).016 Plasma lactate level 1.17 ( ).034 Serum creatinine level 1.74 ( ).044 NOTE. Additional factors entered into the model but rejectedwereprimary drug treatment, hematocrit, log parasitemia, and systolic blood pressure at the time of admission. edema or who required furosemide and/or dopamine, dialysis, urinary catheters, or central venous access (table 3). Shorter parasite clearance time in association with artesunate treatment is a consistent finding in studies comparing the ar- 14 CID 2003:37 (1 July) Newton et al.

9 Figure 3. Geometric mean parasitemia (95% CI) vs. time among subjects included in a study comparing artesunate (open circles) and quinine (solid circles) for the treatment of malaria in Thailand. temisinin derivatives with other antimalarial drugs [11, 25, 39]. The single patient who experienced early (RII) failure despite receiving high doses of quinine is of concern. A patient who died as a result of severe malaria with RIII resistance to intravenous quinine has been described [9], but the plasma quinine levels in that patient, despite use of a conventional body-weight dose regimen, were lower than the minimum therapeutic concentration. High-grade resistance of P. falciparum to quinine has been reported elsewhere in Southeast Asia, but the absence of drug measurements makes interpretation in this case difficult [5 8]. There is no evidence of a major decrease in quinine efficacy in treating severe malaria. Reports of serious adverse events attributable to artesunate use are very rare [34]. The development of a rash after receipt of intravenous artesunate, as described in 1 patient in the present study, is consistent with a recent report of 2 patients who developed urticarial rashes after receiving oral artesunate [45]. The patient we described had multiple poor prognostic signs, and the subsequent fatal clinical course was consistent with severe malaria. However, the possibility of an idiosyncratic artesunate reaction cannot be excluded. Case reports have described neurological abnormalities after artemisinin-derivative treatment of falciparum malaria [46, 47], but these abnormalities are much more likely to be a consequence of malaria itself than of the treatment [48, 49]. In a larger trial of intramuscular quinine versus artemether in Vietnamese adults with severe malaria, artemether was associated with prolonged fever clearance times, coma recovery times, and duration of hospitalization [20]. This was not found in the present trial. Although our study suggests that artesunate may be superior to quinine in the treatment of adults with severe malaria, clinical malaria research is rife with examples of small studies that provide evidence of a new (lifesaving) treatment for severe malaria that is not supported by subsequent larger trials [2, 50]. A large international multicenter trial is required to test whether artesunate is associated with reduced mortality in comparison to quinine. A power calculation that uses the data presented here suggests that a minimum sample size of 960 patients would be required (80% power and 95% confidence), assuming that a 33% reduction from a 22% mortality would be clinically significant (to detect a 20% reduction in mortality would require an estimated 2600 patients). Until such data are available, the results of this trial suggest that artesunate is equivalent to quinine in the treatment of severe malaria in adults in Thailand and that it is associated with faster parasite clearance and a lower prevalence of hypoglycemia. Acknowledgments We are grateful to the directors, doctors, and nurses of Sangklaburi and Mae Sot Hospitals, especially Itaporn Thaiaporn and Jantipa Sutham, for their interest and support; Thanongsak Teewarakulpana, for language translation; and Tip Ruechaitrakul, for logistical help. Kenechanh Chanthapadith, Impone Vangkonevilay, Jamie and Sarah Craig, Juanita de Lope, Michele van Vugt, and Mayfong Mayxay helped with patient care. We thank Lizzy Kissinger, Tan Chongsuphajaisiddhi, Kesinee Chotivanich, Sayan Langla, Kongpop Pupae, Nitirat Thima, Nick Day, and Kasia Stepniewska, for their help and advice. References 1. White NJ, Warrell DA, Chanthavanich P, et al. Severe hypoglycemia and hyperinsulinemia in falciparum malaria. N Engl J Med 1983; 309: White NJ. The treatment of malaria. N Engl J Med 1996; 335: World Health Organization. Severe and complicated malaria. Trans R Soc Trop Med Hyg 1990; 84(Suppl 2): Pukrittayakamee S, Supanaranond W, Looareesuwan S, Vanijanonta S, White NJ. Quinine in severe falciparum malaria: evidence of declining efficacy in Thailand. Trans R Soc Trop Med Hyg 1994; 88: Pinswadi K, Chaereonkwan P. Sluggish response of a case of falciparum malaria to intensive quinine therapy. J Med Assoc Thai 1965; 48: Clyde DF, Miller RM. Treatment of falciparum malaria caused by strains resistant to quinine. JAMA 1970; 213: Jaroovesma N, Harinasuta T, Muangmanee L. Recrudescence, poor Artesunate vs. Quinine in Severe Malaria CID 2003:37 (1 July) 15

10 response or resistance to quinine of falciparum malaria in Thailand. Southeast Asian J Trop Med Public Health 1974; 5: Giboda M, Denis MB. Response of Kampuchean strains of Plasmodium falciparum to antimalarials. In vivo assessment of quinine and quinine plus tetracycline: multiple drug resistance in vitro. J Trop Med Hyg 1988; 91: Looareesuwan S, Charoenpan P, Ho M, et al. Fatal Plasmodium falciparum malaria after an inadequate response to quinine treatment. J Infect Dis 1990; 161: Li GQ, Guo XB, Jin R, Wang ZC, Jian HX, Li ZY. Clinical studies on treatment of cerebral malaria with qinghaosu and its derivatives. J Tradit Chin Med 1982; 2: Hien TT, White NJ. Qinghaosu. Lancet 1993; 341: Li Y, Wu Y-L. How Chinese scientists discovered quinhaosu (artemisinin) and developed its derivatives? What are the future perspectives? Med Trop (Mars) 1998; 58(Suppl): Meshnick SR, Taylor TE, Kamchonwongpaisan S. Artemisinin and the antimalarial endoperoxides: from herbal remedy to targeted chemotherapy. Microbiol Rev 1996; 60: Van Agtmael MA, Eggelte TA, van Boxtel CJ. Artemisinin drugs in the treatment of malaria: from medicinal herb to registered medication. Trends Pharmacol Sci 1999; 20: Nosten F, van Vugt M, Price R, et al. Effects of artesunate-mefloquine combination on incidence of Plasmodium falciparum malaria and mefloquine resistance in western Thailand: a prospective study. Lancet 2000; 356: Price RN, Nosten F, Luxemburger C, et al. Effects of artemisinin derivatives on malaria transmissibility. Lancet 1996; 347: Barradell LB, Fitton A. Artesunate. Drugs 1995; 50: Newton PN, Suputtamongkol Y, Teja-Isavadharm P, et al. Antimalarial bioavailability and disposition of artesunate in acute falciparum malaria. Antimicrob Agents Chemother 2000; 44: Price RN, van Vugt M, Nosten F, et al. Artesunate versus artemether for the treatment of recrudescent multidrug-resistant falciparum malaria. Am J Trop Med Hyg 1998; 59: Hien TT, Day NPJ, Phu NH, et al. A controlled trial of artemether or quinine in Vietnamese adults with severe falciparum malaria. N Engl J Med 1996; 335: Murphy SA, English M, Waruiru C, et al. An open randomized trial of artemether versus quinine in the treatment of cerebral malaria in African children. Trans R Soc Trop Med Hyg 1996; 90: Van Hensbroek MB, Onyiorah E, Jaffer S, et al. A trial of artemether or quinine in children with cerebral malaria. N Engl J Med 1996; 335: Thuma PE, Bhat GJ, Mabeza GF, et al. A randomised controlled trial of artemotil (b-arteether) in Zambian children with cerebral malaria. Am J Trop Med Hyg 2000; 62: Pittler MH, Ernst E. Artemether for severe malaria. Clin Infect Dis 1999; 28: A meta-analysis using individual patient data of trials comparing artemether with quinine in the treatment of severe falciparum malaria. Artemether-Quinine Meta-analysis Study Group. Trans R Soc Trop Med Hyg 2001; 95: Moyou-Somo R, Tietche F, Ondona M, et al. Clinical trial of b-arteether versus quinine for the treatment of cerebral malaria in children in Yaounde, Cameroon. Am J Trop Med Hyg 2001; 64: Phuong CXT, Bethell DB, Phuong PT, et al. Comparison of artemisinin suppositories, intramuscular artesunate and intravenous quinine for the treatment of severe childhood malaria. Trans R Soc Trop Med Hyg 1997; 91: Hien TT, Phu NH, Mai NTH, et al. An open randomised comparison of intravenous and intramuscular artesunate in severe falciparum malaria. Trans R Soc Trop Med Hyg 1992; 86: Win K, Than M, Thwe Y. Comparsion of combinations of parenteral artemisinin derivatives plus oral mefloquine with intravenous quinine plus oral tetracycline for treating cerebral malaria. Bull World Health Organ 1992; 70: Teja-Isavadharm P, Nosten F, Kyle DE, et al. Comparative bioavailability of oral, rectal and intramuscular artemether in healthy subjects: use of simultaneous measurement by high performance liquid chromatography and bioassay. Br J Clin Pharmacol 1996; 42: Murphy SA, Mberu E, Muhia D, et al. The disposition of intramuscular artemether in children with cerebral malaria: a preliminary study. Trans R Soc Trop Med Hyg 1997; 91: Brockman A, Price RN, van Vugt M, et al. Plasmodium falciparum antimalarial drug susceptibility on the northwestern border of Thailand during five years of extensive artesunate-mefloquine use. Trans R Soc Trop Med Hyg 2000; 94: Nontprasert A, Nosten-Bertrand M, Pukrittayakamee S, Vanijanonta S, Angus BJ, White NJ. Assessment of the neurotoxicity of parenteral artemisinin derivatives in mice. Am J Trop Med Hyg 1998; 59: Price RN, van Vugt M, Phaipun L, et al. Adverse effects in patients with acute falciparum malaria treated with artemisinin derivatives. Am J Trop Med Hyg 1999; 60: Luxemburger C, Ricci F, Nosten F, Raimond D, Bathet S, White NJ. The epidemiology of severe malaria in an area of low transmission in Thailand. Trans R Soc Trop Med Hyg 1997; 91: Mai NTH, Day NPJ, Chuong LV, et al. Post-malaria neurological syndrome. Lancet 1996; 348: Silamut K, White NJ. Relation of the stage of parasite development in the peripheral blood to prognosis in severe falciparum malaria. Trans R Soc Trop Med Hyg 1993; 87: Silamut K, Hough R, Eggelte T, Pukrittayakamee S, Angus B, White NJ. A simple method for assessing quinine pre-treatment in acute malaria. Trans R Soc Trop Med Hyg 1995; 89: White NJ. Assessment of the pharmacodynamic properties of antimalarial drugs in-vivo. Antimicrob Agents Chemother 1997; 41: Angus BJ, Chotivanich K, Udomsangpetch R, White NJ. In vivo removal of malaria parasites from red blood cells without their destruction in acute falciparum malaria. Blood 1997; 90: Dondorp AM, Angus BJ, Hardeman MR, et al. Prognostic significance of reduced red cell deformability in severe falciparum malaria. Am J Trop Med Hyg 1997; 57: Newton PN, Chotivanich K, Chierakul W, et al. A comparison of the in vivo kinetics of Plasmodium falciparum ring-infected erythrocyte surface antigen (RESA) positive and negative erythrocytes. Blood 2001; 98: World Health Organization. Chemotherapy of malaria and resistance to antimalarials: report of a WHO scientific group. World Health Organ Tech Rep Ser 1973; 529: Seguro AC, Campos SB. Diuretic effect of sodium artesunate in patients with malaria. Am J Trop Med Hyg 2002; 67: Leonardi E, Gilvary G, White NJ, Nosten F. Severe allergic reaction to oral artesunate: a report of two cases. Trans R Soc Trop Med Hyg 2001; 95: Miller LG, Panosian CB. Ataxia and slurred speech after artesunate treatment for falciparum malaria. N Engl J Med 1997; 336: Elias Z, Bonnet E, Marchou B, Massip P. Neurotoxicity of artemisinins: possible counseling and treatment of side effects. Clin Infect Dis 1999; 28: Davis TME, Edwards GO, McCarthy JS. Artesunate and cerebellar dysfunction in falciparum malaria. N Engl J Med 1997; 337: White NJ. Neurological dysfunction following malaria: disease- or drug-related [letter]? Clin Infect Dis 2000; 30: Newton PN, White NJ. Malaria: new developments in treatment and prevention. Annu Rev Med 1999; 50: CID 2003:37 (1 July) Newton et al.