Background
In Zambia, malaria treatment and control have been undermined by the emergence of resistance to commonly-used antimalarial drugs such as chloroquine (CQ) and sulfadoxine-pyrimethamine (SP)
The results of a randomized clinical trial on the efficacy of SP compared to AL in adult patients with uncomplicated malaria in Ndola, Zambia, are reported below. Patients were followed up for 45 days.
Methods
Study participants
The study started in March 2003, during the antimalarial drug policy transition from SP to AL, and was completed in June 2005. Patients were recruited at 4 peri-urban health centers in Ndola, Zambia, an area of mesoendemic malaria where transmission is perennial with a seasonal peak from November to April. A reliable ambulance service is available and patients requiring hospitalization can be referred to Ndola Central Hospital, about 5 km away. All individuals aged 15–50 years attending any of the 4 peri-urban clinics and presenting with fever (body temperature ≥ 37.5°C), and/or history of fever in the previous 48 hours, and without any other obvious disease were screened for malaria infection (thick and thin blood film in duplicate for parasite density and species identification) and pregnancy (if applicable). Patients with a
Enrolment, treatment and follow up
Patients were randomly allocated by blocks of 10 (according to a pre-established list) to receive either SP (Fansidar®, Roche: 500 mg sulfadoxine/25 mg pyrimethamine tablets), single dose of 3 tablets (2.5 tablets if < 50 kg), or AL (Coartem®, Novartis: 20 mg artemether/120 mg lumefantrine tablets), 4 tablets immediately followed by 4 tablets at 8, 24, 36, 48 and 60 hours, taken with a creamy snack. Treatment allocation was concealed until final recruitment. SP treatment was directly observed and patients were monitored at the health centre for at least 30 minutes after treatment. For AL, the morning doses were directly observed over the 3 days of treatment, while the evening doses were given to the patients to be taken at home, and empty sachets returned as evidence of taking the drug. Paracetamol tablets (3 doses/day for 2 days) were provided, to be taken when needed.
Clinical history, signs and symptoms, body temperature were recorded and a blood sample for parasitaemia (blood slide) and for molecular analysis (on Schleicher & Schuell filter paper) were collected at days 0, 3, 7, 14, 21, 28 and 45 or at any unscheduled visit. The blood sample on filter paper was dried at room temperature and stored at -20°C with silica gel. At day 0 (before treatment), a drop of venous blood was collected for Hb measurement (HaemoCue®). Hb was measured again at day 14 and 45. Patients were encouraged to attend the health facility outside scheduled visits if they felt ill. Patients treated with SP and classified as failures (clinical or parasitological) were treated with AL, while those on AL received quinine. Adverse events were documented and treated accordingly.
Patients were excluded during follow up for the following reasons: self-administration of other antimalarial drugs, emergence of any concomitant febrile illness that interfered with outcome classification, development of hypersensitivity to the study drug, withdrawal of informed consent.
Laboratory investigations
All lab technicians were blinded to the patient's identity and all patient-related parameters. Thin blood films were fixed with methanol and thin and thick blood films were stained with 10% Giemsa. At the clinic, the number of asexual
Assessment of outcome
Outcome of treatment was defined according to the standard WHO classification (WHO 2003): Early Treatment Failure (ETF) was defined as: i) danger signs of/or severe malaria on days 1, 2 or 3 with parasitaemia; ii) parasite density at day 2 greater than at day 0; iii) parasitaemia on day 3 with axillary temperature ≥ 37.5°C and iv) parasite density at day 3 equal or greater than 25% of that at day 0. Late Clinical Failure (LCF) was defined as danger signs of/or severe malaria and/or parasitaemia with axillary temperature ≥ 37.5°C between day 4 and day 45, without having been previously classified as ETF. Late parasitological failure (LPF) was defined as reappearance of parasitaemia between day 4 and day 45 without fever and without previously meeting any of the criteria for ETF or LCF. An adequate clinical and parasitological response (ACPR) was defined as absence of parasitaemia by day 45 without previously meeting any of the criteria for ETF, LCF and LPF. The overall rate of treatment failure (Total Treatment Failure TTF) was computed as if the patient had an ETF, LCF or a LPF. Only parasitaemia confirmed by PCR as recrudescence was considered as treatment failure. Patients were also considered treatment failures if they received rescue treatment on or before day 45. As both drugs were registered and used in Zambia, no stopping rules were defined.
All adverse events (AEs) were recorded on the Case Record Form (CRF). An AE was defined as "any unfavorable and unintended sign, symptom, or disease temporally associated with the use of the drug administered". A causality assessment of the AEs was done according to the guidelines of WHO-Uppsala Monitoring Centre (WHO-UMC).
Statistical analysis
Data were double entered and cleaned in Epi-info (version 6.04b; Centre for Disease Control and Prevention). All analyses were performed using STATA statistical analysis software package version 8 (Stata Corp., College Station, TX, USA, 2003). Proportions were compared using the χ2 or Fisher's exact test (when required); Student's t-test was used for continuous variables. Paired t-test was used for within patient comparisons. All reported p-value are two-sided. Non-parametric tests (Wilcoxon or Kruskal-Wallis) were used for non-normally distributed variables. For the intention-to-treat analysis the log-rank test and the Hazard Ratio (Cox regression) were estimated after testing for proportional hazard assumption (Schoenfeld test). Data of the patients excluded or lost to follow up were censored at the time of the last recorded visit. All possible interactions up to order two were tested.
Results
Enrollment
Between March 2003 and June 2005, a total of 971 patients were randomized to either SP (486) or AL (485). At enrolment the 2 groups had similar demographic and clinical characteristics (Table
Baseline characteristics by treatment (%)
SP
N = 486
AL
N = 485
Mean weight (Kg) (SD)
56.4 (10.1)
56.3 (9.6)
Number of women (%)
245 (50.5)
230 (47.4)
Mean age (yr) (SD)
27.0 (8.9)
26.3 (8.3)
Mean body temperature (°C) (SD)
37.2 (1.2)
37.3 (1.3)
Mean white blood cell count (n*109/l) (SD)*
5.1 (1.8)
5.2 (1.8)
Mean Hb (g/l) (SD)
13.0 (2.2)
13.2 (2.3)
Mean (geometric) parasite density(/μl) (range)*
8787 (406 – 103680)
8405 (350–158894)
Gametocytes prevalence (n)(%)
16 (3.3)
18 (3.7)
N = 477
N = 481
Weakness (%)
344 (72.1)
365 (75.9)
Headache (%)
428 (89.7)
429 (89.2)
Muscle/joint pain (%)
316 (66.2)
318 (66.2)
Dizziness (%)
176 (36.9)
177 (36.7)
Nausea (%)
190 (39.9)
180 (37.5)
Vomiting (%)
104 (21.7)
113 (23.5)
Diarrhoea (%)
62 (13.1)
59 (12.2)
Abdominal pain (%)
172 (36.1)
163 (33.8)
Heart palpitations (%)
76 (16.0)
76 (15.7)
Backache (%)
105 (22.0)
119 (24.7)
Jaundice** (%)
51 (10.7)
104 (21.7)
Pallor** (%)
6 (1.3)
1 (0.3)
Dark urine (%)
51 (10.6)
48 (9.9)
*Data on WBC were missing in 4 patients in the SP group and in 7 in the AL group. Parasite density was calculated based on the parasites/WBC ratio.
** Jaundice and pallor in 302 patients in the SP and and 301 in the AL group.
Trial profile
By day three, 35 (3.6%) patients were lost to follow up and 120 (12.4%) by day 45; 12 patients withdrew and 9 were excluded (4 hospitalized for reasons not linked to treatment or malaria and 5 took other antimalarial drugs). The percentage of lost to follow up were similar in both treatment arms (AL: 83/486
Analysis of efficacy
SP and AL were generally well tolerated. Almost all clinical symptoms cleared faster with AL (Table
Clinical and parasitological evolution during follow up by treatment.
Day 3
Day 7
Day 14
Day 28
SP
AL
P
SP
AL
P
SP
AL
P
SP
AL
P
N
430
451
405
436
384
406
290
320
Fever (%)
3.5
0.9
0.007
1.0
1.1
0.55
1.3
1.0
0.75
2.7
1.2
0.19
Parasitaemia
15.0
0.7
<0.001
2.0
0.0
NA
2,
0;5
0.009
5.5
1.2
0.003
Hemoglobin (mean)*(g/L)
-
-
-
-
124
129
0.003
130
134
0.02
Gametocyte carriage (N (%))
33 (7.6)
3 (0.7)
<0.001
88 (21.6)
2 (0.5)
<0.001
76 (19.8)
0 (0)
NA
10 (4.5)
1 (0,3)
0.004
Gametocyte densities (range)
48.6 (1–4320)
6.2 (1–240)
0.62
63.6 (1–4480)
8.9 (1–80)
0.51
52.8 (1–6960)
0(0)
NA
154.9 (3–840)
160
NA
N
430
448
400
428
382
401
303
329
Weakness (%)
46.3
20.5
<0.001
15.0
6.1
<0.001
7.1
3.7
0.04
5.9
3.0
0.08
Headache (%)
45.6
22.5
<0.001
18.0
12.2
0.02
10.7
8.5
0.28
11.5
10.3
0.62
Muscle joint pain (%)
20.3
8.2
<0.001
5.2
2.6
0.004
3.8
2.8
0.47
2.3
2.8
0.73
Dizziness (%)
20.0
10.8
<0.001
5.2
3.0
0.11
2.1
1.0
0.21
2.7
1.2
0.18
Nausea (%)
15.8
2.9
<0.001
1.3
0.0
NA
0.8
0.5
NA
0.7
0.6
NA
Vomiting (%)
5.8
0.7
<0.001
0.5
0.2
NA
0.5
0.5
NA
0.0
0.3
NA
Diarrhoea (%)
3.8
7.7
0.013
0,9
2.5
0.08
1.3
2.7
0.16
0.7
1.2
0.78
Abdominal pain (%)
16.7
9.2
<0.001
7.0
4.0
0.06
3.4
3.5
0.94
5.0
3.7
0.41
Hear palpitations (%)
9.8
5.1
0.008
5.5
4.2
0.38
5.8
8.0
0.61
4.6
7.3
0.88
Back ache (%)
10.9
8.9
0.32
7.0
7.7
0.53
5.8
8.0
0.22
4.6
7.3
0.15
In bold P value < 0,05; Other symptoms had low frequency or were not significantly different at day 3. Fisher exact (2-tailed) used where indicated. No significant differences at day 45 (data not shown). NS = not significant/NA = not applicable. * Haemoglobine day 14 and day 45 (P value: Barlett's test)
PCR corrected clinical and parasitological failure at day 45 by treatment.
Treatment outcome n/N (%)
SP
AL
OR (95% CI)
P-value
ETF
25/465 (6.4)
2/462 (0.5)
13.1 (3.08–55.50)
<0.001
LCF
33/391 (8.4)
14/404 (3.5)
2.55 (1.34–4.84)
0.004
LPF
18/391 (4.6)
6/404 (1.5)
3.18 (1.25–8.09)
0.02
TTF (PCR corrected)
76/391 (19.3)
22/404 (5.4)
4.15 (2.52–6.83)
<0.001
Log-rank test and Cox regression gave identical results to the per protocol analysis (Figure
Serious adverse events were observed in 2 patients treated with SP (one hospitalized for severe headache received quinine and one developed hypoglycemia) and one treated with AL who developed a rash. Eleven patients (5 on AL and 6 on SP) had various symptoms possibly related to the study drugs but none serious enough to interrupt the treatment.
Discussion
This trial was conducted in Zambia where a six-dose regimen of AL has been recently implemented as the first line treatment for uncomplicated malaria in non-pregnant adults and children over 10 kg. However, SP was still the standard therapy in March 2003 and this treatment was used as control. AL was clearly better than SP for several outcomes such as parasitological clearance, resolution of symptoms and safety. Hb followed a similar pattern, the drop observed at day 14 was more pronounced and the hematological recovery by day 45 lower in the SP arm. As expected, SP-treated patients had a significantly higher prevalence of gametocytes even if some patients treated with AL had gametocytes at day 28. These results confirm previous findings
Despite the high cure rate, a similar rate of new infections was observed in both treatment groups. This is a concern as routine services do not make any distinction between recrudescence and new infections. In this mesoendemic study area, the ratio new infections/recrudescence was relatively low but in places where the malaria transmission is more intense it could increase substantially. The new infections and the residual number of parasites of the 'old' infection would be exposed to sub therapeutic doses of lumefantrine, the long acting partner drug in the AL combination, and this might increase the selection of resistant strains
In Zambia, HIV-1 prevalence is estimated at 25.2 % among mothers attending the antenatal clinic
Conclusion
In conclusion, this study, despite the incompletely supervised treatment, confirmed the excellent efficacy and safety/tolerability of the six-dose AL in adults. Next to pharmacovigilance, further research is still needed to ensure its correct deployment, possibly to pregnant women.
Authors' contributions
Modest Mulenga organized the collection of data, supervised the trial and contributed to the data interpretation and writing the paper. Jean-Pierre Van geertruyden contributed to the analysis plan, data interpretation, produced the final dataset, did the analysis and wrote the paper. Lawrence Mwananyanda organized the collection of data, supervised the trial and contributed to the data interpretation and writing the paper, Victor Chalwe supervised the trial and contributed to the data interpretation, Filip Moerman contributed to the study design and training. Roma Chilengi contributed to the study design and training. Chantal Van Overmeir and Jean-Claude Dujardin organized the PCR essays. Umberto D'Alessandro contributed to the study design, the analysis plan, data interpretation and the writing of the paper.
Trial profile
Trial profile. Legend: † 2 ETF in HIV-1 were serious adverse events. †† Patients facing an event (excluded, lost to follow up or new infection) were censored at the time of the last recorded visit and included in the survival analysis.
The cumulative risk of recrudescence in adults with non-complicated malaria (N = 971)
The cumulative risk of recrudescence in adults with non-complicated malaria (N = 971). All patients were censored at their last visit. A dotted line represents sulfadoxine-Pyrimethamine and a solid line Artemether-Lumefantrine (Zambia 2005).