Therapeutic efficacy of dihydroartemisinin-piperaquine and artesunate-pyronaridine combinations in the treatment of uncomplicated Plasmodium falciparum malaria in Ghana, 2023

Introduction: Malaria case management in Ghana is a key intervention within the national malaria elimination agenda. Currently, artesunate-amodiaquine (AS-AQ), artemetherlumefantrine (AL), and artesunate-pyronaridine (AP) are the first-line medicines for treating uncomplicated malaria whilst dihydroartemisinin-piperaquine (DHAP) is the second-line medicine. Methods: This was a one-arm prospective evaluation of the clinical, parasitological and haematological responses of children (6 months to 9 years old) treated with DHAP in five (5) sentinel sites and AP in four (4) sentinel sites between August and December, 2023 using the WHO protocol on surveillance of antimalarial drug efficacy. The DHAP study was a follow-up to the baseline conducted in 2020/2021, and the AP study was to provide baseline data after its introduction in 2022. The 3/3 PCR-genotyping approach distinguished between reinfection and recrudescence using merozoite surface protein 1 (msp1)-specific primers: RO33, MAD20, K1; merozoite protein 2 (msp2)-specific primers: IC 3D7 and FC; and glutamate-rich protein (glurp). Results: PCR-uncorrected cure rates on day-42 ranged between 98.8% (95% CI: 93.2-100) and 100% for DHAP with an overall PCR-uncorrected cure rate of 99.2% (95% CI: 97.6-99.8); and between 85.0% (95% CI: 70.2-94.3) and 100% for AP with an overall PCR-uncorrected cure rate of 96.2% (95% CI: 92.9-98.0). PCR-corrected cure rates on day-42 was 100% in all DHAP sites; and ranged between 91.9% (95% CI: 78.1-98.3) and 100% for AP with an overall PCR-corrected cure rate of 97.3% (95% CI: 94.3-98.8). Day-3 parasitemia was prevalent in only one (1) DHAP site (1/60 – 1.7%) and one (1) AP site (1/65 – 1.5%) with an overall prevalence of 0.3% for DHAP and 0.4% for AP. Neither treatment with DHAP nor AP resulted in an early treatment failure (ETF). Conclusion: We conclude that the therapeutic efficacy level of DHAP has remained high (>90%) since the baseline study in 2020/2021. Also, the baseline efficacy level of AP is high (>90%) warranting the use of both DHAP and AP in the treatment of uncomplicated malaria in the country.