Artemisinin-Based Combination Therapies in East Africa: A Systematic Review of Quality, Clinical Efficacy, and Regulatory Progress Towards Sustainable Malaria Control

Abstract

Background: Malaria is a major public health issue in East Africa, leading to widespread illness and fatalities, especially among vulnerable populations such as children under 5 years of age and pregnant women. Artemisinin-based combination therapies (ACTs) are the primary treatment modality; however, their efficacy is undermined by the prevalence of substandard ACTs and the increasing risk of resistance. Therefore, it is crucial to improve evidence on quality, therapeutic efficacy, and regulatory performance to promote malaria control efforts in the region.

Methods: This systematic review followed PRISMA 2020 guidelines, with the protocol registered in PROSPERO (CRD420251135109). Literature was searched in PubMed and Google Scholar databases from July to September 2025. Methodological quality was appraised using MEDQUARG and STROBE. Two reviewers independently extracted data, resolving discrepancies by consensus. The extracted findings were synthesised narratively to identify key trends.

Results: A systematic review of 40 articles from Ethiopia, Kenya, Tanzania, and Uganda revealed considerable variation in the quality of Artemisinin-based combination therapies (ACTs). Across the four East African countries, a total of 3363 ACT samples were tested, of which 375 failed to comply with specification limits set for at least one physicochemical quality parameter. This corresponds to an overall failure rate of 11.2% (375/3363). Country-specific failure rates reflect the highest rate in Uganda (33.3% [16/48]), followed by Kenya (14.1% [10/71]), Tanzania (11.6% [333/2859]), and Ethiopia (4.2% [16/385]). This considerable variation could be attributed to the differences in prevalence, the number of studies conducted, study design, and sampling methodology. The reported poor quality of ACTs, major treatment options in managing malaria cases, could pose a public health threat. Though the studies conducted so far may not give a real picture of the magnitude of poor quality ACTs medicines and their impact on the treatment outcomes, the reports indicated that ACTs remain highly efficacious, with most therapeutic trials reporting polymerase chain reaction-corrected cure rates of ≥ 90%. As indicated in the literature, Artemether-lumefantrine consistently demonstrated strong treatment outcomes, while dihydroartemisinin-piperaquine provided extended prophylactic effects. However, emerging Plasmodium falciparum resistance, particularly K13 mutations associated with delayed parasite clearance, poses an ongoing threat to ACT effectiveness.

Conclusion: The findings of this study revealed that 11.2% of ACTs samples were found to be poor quality. The clinical data reflects that in East Africa, ACTs remain effective despite the prevalence of substandard and falsified ACTs and emerging resistance threatening long-term gains. Thus, strengthening regional regulatory harmonization, pharmacovigilance, molecular surveillance, and local manufacturing capacity is essential to combat resistance of ACT and ensure equitable access to quality-assured therapies.

Keywords: Artemisinin‐based combination therapies; East Africa; clinical concern; efficacy; quality; regulatory performance; resistance.