The Study Group pooled 83 studies (29,493 patients) conducted between 1999 and 2012; including 15 unpublished studies and 68 published studies. Out of these 83 studies, 34 were conducted in West Africa (n=10,676), 31 in East Africa (n=8,331), four in Central Africa (n=631), four studies in Southern Africa (n=666), and the remaining ten studies were multi-regional (n=9,211).
46% (n=13,664) of patients from the studies were treated with artemether-lumefantrine, 17% (n=4,907) with the fixed dose combination of AS-AQ (ASAQ-FDC), 13% (n=3,925) with the non-fixed dose combination of AS-AQ in loose formulation (ASAQ-Loose NFDC), 9% (n=2,505) with the non-fixed dose combination of AS-AQ in co-blister formulation (ASAQ-Co-blistered NFDC), and 15% (n=4,492) with dihydroartemisinin-piperaquine (DP).
The Study Group formed in October 2011, with an open invitation to join and share data. Research groups with relevant data sets were contacted between October and November 2011. Potential participants met at the December 2011 ASTMH Annual Meeting to discuss governance and publication policy. The study group closed in March 2013. The latest results were presented at the BMC Challenges in malaria research conference in September 2014 in Oxford, UK; and at the RSTMH Biannual Meeting September 2014 in Oxford, UK. The results: Clinical determinants of early parasitological response to ACTs in African patients with uncomplicated falciparum malaria: a literature review and meta-analysis of individual patient data were published in BMC Medicine in September 2015.
Current guidelines recommend in-depth assessment for the presence of malaria drug resistance in a specific geographical region if malaria parasites are still present in the blood of over 10% of patients three days after treatment. The final results of the study suggest that the recommended threshold should be decreased from 10% to 5% for African populations. Lowering the percentage could mean that monitoring mechanisms would be able to identify areas at high risk of resistance early on, so that appropriate intervention measures could be taken.