Journal of Infectious Diseases Advance Access published July 15, 2014

MAJOR ARTICLE

Randomized Trial of Artesunate-Amodiaquine, Atovaquone-Proguanil, and ArtesunateAtovaquone-Proguanil for the Treatment of Uncomplicated Falciparum Malaria in Children Rachida Tahar,1,4 Talleh Almelli,1 Camille Debue,1 Vincent Foumane Ngane,4 Joseph Djaman Allico,2,5,6 Solange Whegang Youdom,4 and Leonardo K. Basco3,4,a Downloaded from http://jid.oxfordjournals.org/ at New York University on February 17, 2015

1 Unité Mixte de Recherche 216 Mère et Enfant Face aux Infections Tropicales, Institut de Recherche pour le Développement (IRD), Unité de formation et de recherche de Pharmacie, Paris, 2Unité de Recherche Neurobiologie et Développement, Unité Propre de Recherche 3294, Centre National de la Recherche Scientifique, Université Paris-Sud XI, Orsay, and 3Unité de Recherche 198, Unité de Recherche des Maladies Infectieuses et Tropicales Emergentes, IRD, Faculté de Médecine La Timone, Aix-Marseille Université, Marseille, France; 4Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale, Yaoundé, Cameroon; 5Laboratoire de Pharmacodynamie Biochimique, Unité de Formation et de Recherche Biosciences, Université de Cocody, and 6Département de Biochimie, Institut Pasteur de Côte d’Ivoire, Abidjan, Côte d’Ivoire

Background. Artemisinin-based combination therapies (ACTs) are recommended for the treatment of acute uncomplicated falciparum malaria in many malaria-endemic countries. Despite the emergence of artemisinin resistance, few alternative non-ACTs, including atovaquone-proguanil, are currently available. Methods. Plasmodium falciparum–infected Cameroonian children ≤5 years old (n = 338) were randomly assigned to artesunate-amodiaquine, atovaquone-proguanil, or artesunate-atovaquone-proguanil treatment groups and followed for 28 days, according to the standard World Health Organization protocol. In vitro response to atovaquone and cytochrome b sequence of clinical isolates were determined. Results. Eight late failures and 16 failures (8 late and 8 early failures) were observed after artesunateamodiaquine and atovaquone-proguanil therapies, respectively. Most late failures were due to reinfections. Artesunateatovaquone-proguanil was not associated with any failure. After correction by genotyping, per-protocol analysis showed no difference in the efficacy of 3 drugs. However, the proportion of atovaquone-proguanil–treated patients with positive smears on day 3 was much higher (36.0%; P < .05) than that of the artesunate-amodiaquine (2.9%) and artesunate-atovaquone-proguanil (1.0%) groups. In vitro response and cytochrome b sequence did not indicate atovaquone resistance. Conclusions. Atovaquone-proguanil was characterized by a slow blood schizontocidal action and resulted in early treatment failure in a few patients. Artesunate-atovaquone-proguanil was a highly effective alternative treatment. Clinical Trials Registration. UMIN000003813. Keywords.

drug resistance; Plasmodium falciparum; cytochrome b; artemisinin; molecular epidemiology.

Received 8 February 2014; accepted 30 May 2014. a Present affiliation: Unité de Parasitologie, Institut de Recherche Biomédicale des Armées, Ancienne Base Aérienne 217, Brétigny-sur-Orge, France. Correspondence: Leonardo K. Basco, MD, PhD, Unité de Parasitologie, Institut de Recherche Biomédicale des Armées, Ancienne Base Aérienne 217, 91223 Brétignysur-Orge, France ([email protected]). The Journal of Infectious Diseases © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: [email protected]. DOI: 10.1093/infdis/jiu341

Artemisinin-based combination therapies (ACTs) are the current drugs of choice for the treatment of acute uncomplicated Plasmodium falciparum malaria in many parts of the world where malaria is endemic. Artesunate-amodiaquine (ASAQ) and artemetherlumefantrine have been adopted for first- or secondline treatment in many sub-Saharan African countries, including Cameroon. Although these 2 ACTs are highly effective and rapidly acting and resistance has not been Atovaquone-Proguanil Treatment for Malaria

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PATIENTS, MATERIALS, AND METHODS Patients

Clinical studies were conducted at Nlongkak Catholic missionary dispensary (Yaoundé, Cameroon) in 2008–2009. Malaria transmission occurs throughout the year in Yaoundé. The entomological inoculation rate varies from 3 to 34 infective bites per person per year [32–34]. Symptomatic patients with acute uncomplicated malaria were enrolled, after free and informed consent was received from the parents or legal guardians, if the following inclusion criteria were met: age between 6 months old and 5 years, fever at the time of consultation (measured rectal temperature, ≥38.0°C), and parasite density of ≥2000 asexual P. falciparum parasites/µL of blood, without other Plasmodium species [35]. In addition, because of limited data on the safety of ATPG for treatment in children weighing .05; Supplementary Figure 1). The log-rank survival analysis showed similar results. There was no statistically significant difference (P = .649) in the PCR-uncorrected survival data for the ASAQ and ATPG-1 groups, whereas the paired survival curves for the ATPG-2 and AS-ATPG groups were significantly different (P = .006; Supplementary Figure 2). After correction by genotyping, ITT analysis of day 28 data showed that the difference in the proportions of ACPR in the ASAQ and ATPG-1 groups was not statistically significant (OR, 0.66 [95% CI, .27–1.58]; P > .05). PCR adjustment was

Table 3.

Comparison of the Primary Outcome, by the Peto Odds Ratio (OR) Method PCR-Unadjusted Outcome Per Protocol

PCR-Adjusted Outcome

Intention to Treat

Per Protocol

Intention to Treat

Treatment

Peto OR (95% CI)

P

Peto OR (95% CI)

P

Peto OR (95% CI)

P

Peto OR (95% CI)

P

ASAQ ATPG-2

ATPG-1 AS-ATPG

0.21 (0.04–0.97) 7.63 (0.47–123)

.046 .16

0.30 (0.10–0.94) 1.80 (0.53–6.04)

.040 .34

0.12 (0.02–0.62) 7.63 (0.47–123)

.011 .15

0.30 (0.10–0.94) 1.80 (0.53–6.04)

.040 .34

ASAQ

AS-ATPG

11.15 (0.21–595)

.23

1.07 (0.23–4.98)

.93

...

1.07 (0.23–4.98)

.93

Day, Comparator Day 14

Day 28 ASAQ

ATPG-1

0.82 (0.30–2.25)

.69

0.66 (0.27–1.58)

.35

0.34 (0.08–1.42)

.14

0.66 (0.27–1.58)

.35

ATPG-2

AS-ATPG

8.17 (1.81–36.84)

.006

2.87 (1.12–7.36)

.029

8.19 (0.84–79.84)

.070

2.87 (1.12–7.36)

.029

ASAQ

AS-ATPG

12.25 (2.91–51.52)

.006

3.15 (1.08–9.22)

.036

.079

3.15 (1.08–9.22)

.036

12.79 (0.74–219)

Abbreviations: ATPG, atovaquone-proguanil; CI, confidence interval; PCR, polymerase chain reaction.

not required for the AS-ATPG group because of the absence of treatment failure. In the ITT population, AS-ATPG was significantly more effective than ATPG-2 (OR, 2.87 [95% CI, 1.12– 7.36]; P < .05) and ASAQ (OR, 3.15 [95% CI, 1.08–9.22]; P < .05). However, in the PP analysis of PCR-corrected data, the differences in the efficacy of 3 drugs were not statistically significant (P > .05; Supplementary Figure 1). This observation was due to the fact that most treatment failures in the ASAQ and ATPG groups were caused by reinfections that led to censored data. Results of the fixed-effect model were supported by the log-rank survival analysis, which did not show any

Table 4.

statistically significant difference in the PCR-corrected survival curves for the ASAQ and ATPG-1 groups (P = .254) and for the ATPG-2 and AS-ATPG groups (P = .077; Supplementary Figure 2). Secondary Outcomes

A comparable proportion (P > .05) of patients assigned to different treatment arms presented with an initial parasitemia of >100 000 asexual parasites/µL of blood (Table 4 and Supplementary Materials). On day 3, only 2 of 68 patients (2.9%; PP population) treated with ASAQ were afebrile but still had

Secondary Treatment Outcome in the Per-Protocol Population Treatment Group

Outcome

ASAQ

ATPG-1

ATPG-2

AS-ATPG

Patients on days 2 and 3, no. Parasite clearance

68

65

96

98

Positive smear on day 2a

13 (19.1)

51 (78.5)

70 (72.9)

8 (8.2)

2 (2.9)

25 (37.9)

33 (34.4)

1 (1.0)

Fever on day 1

1 (1.5)

5 (7.7)

8 (8.3)

2 (2.0)

Fever on day 2 Fever on day 3

1 (1.5) 1 (1.5)

2 (3.1) 0

6 (6.2) 2 (2.1)

0 1 (1.0)

34.9 ± 2.9 20

33.9 ± 3.9 14

Positive smear on day 3a Fever clearance

Hematocrit Level on day 14 %, mean±SD Increase from days 0 to 14, %b

34.8 ± 2.9 19

32.5 ± 3.8 13

Data are no. (%) of patients, unless otherwise indicated. Abbreviations: ASAQ, artesunate-amodiaquine; AS-ATPG, artesunate-atovaquone-proguanil; ATPG, atovaquone-proguanil. a

Statistically significant difference (P < .05) in the proportions of patients with parasite-positive smears in the ATPG-1 and ATPG-2 groups.

b

In each treatment group, the mean increase in hematocrit on day 14, compared with the pretreatment values, was statistically significant (P < .0001).

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PCR-unadjusted day 14 outcomes were not statistically significant in the intention-to-treat and per-protocol populations. Direct comparison of per-protocol populations on day 14 between the artesunate-amodiaquine (ASAQ) and artesunate-atovaquone-proguanil (AS-ATPG) treatment arms was not done because of 100% efficacy. Statistical significance was defined as a P value of