Nigeria continues to test malaria drug efficacy

At present artemisinin-based combination therapy medicines for malaria are our best hope for treating malaria and have the added benefit of reducing parasite transmission.  If these drugs lose their power, we are in trouble; hence there is need for continued testing to ensure that drug efficacy remains high.

The Nigeria National Malaria Control Program has just circulated its latest malaria drug testing results. All endemic countries should see this as a model for their own continued monitoring of malaria drugs.

nmcp-nigeria-2.jpgA total of 747 children were enrolled in the two treatment arms – artemether-lumefantrine and artesunate-amodiaquine. The sample was drawn from investigations at seven sites in different geographical settings.  Below we find the main points as summarized in the Executive Summary.

1. The Therapeutic Efficacies of two Artemisinin-based Combination Therapies (ACTs) – Artesunate-Amodiaquine (AA) and Artemether-Lumefantrine (AL) were evaluated in 724 children <5 year-old drawn from 7 sentinel sites; Lagos, South-west, South-east, South-south, North-central, North-west and North-east located in 6 geographical zones of Nigeria.

2. All children recovered clinically from their illness. Fever clearance was significantly faster in children treated with AA than in those treated with AL (1.19 ± 0.49 versus 1.33 ± 0.7 d, P= 0.006).

3. Compared with AL, AA significantly reduced the proportion of children with parasitaemia 1 day after treatment began (P=0.016), but parasite clearance times were similar in AA- and AL- treated children (1.13 ± 0.4 versus 1.11 ± 0.34 d, P= 0.47).

4. Overall, adequate clinical and parasitological response (ACPR) on day 28 was 97.4%, and was similar for both AA (95.1%) and AL (96.3) P=0.108). Early treatment failure occurred in one child treated with AA.

5. Overall, PCR-corrected parasitological cure rate on day 28 was 98% and was significantly higher in AA- than in AL- treated children 99.1% (343/346) versus 96.9% (311/321), P=0.048. The cumulative probability of a reappearance of asexual parasitaemia after treatment with AA or AL were similar (Log-rank statistic = 0.027, P=0.869)

6. Recurrent infections were not age or drug dependent. Overall, recrudescence occurred in 5.3% of the children (38 of 711), and was unrelated to age or drug treatment. Recrudescent infections were significantly more common in the eastern flank (North eastern, North central, South eastern than the western flank (North-western, South-western and Lagos) of the sentinel sites [32 of 311 children (10.3%) versus 6 of 319 children (1.9%), P<0.00001].

7. Overall, gametocyte carriage after treatment with both drugs was significantly lower compared with pre-treatment [16 of 491 children (3.3%) versus 46 of 620 children (7.4%), P=0.005].

8. Anaemia, defined as haematocrit <30%, was present in 294 of 672 children (43.8%) and was significantly more common in the eastern than in the western flank of the sentinel sites. Anaemia resolved completely in all anaemic children within 14 days in 93% of the chilldren.

9. In anaemic children, anaemia resolution time was approximately 10 days for both drugs.

10. In the few sentinel sites where adverse drug reactions were monitored, both drugs were tolerated; the reported adverse drug reactions were indistinguishable from the symptoms of malaria.

11. AA and AL are safe and efficacious treatment of uncomplicated P. falciparum malaria in <5 year old Nigerian children.

The full study will be made available at the NMCP’s website.

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