The Transmission of Artemisinin Resistant Parasites Before and After Conventional Artemisinin-combination Therapy

Summary

A prospective study will be carried out in an area where parasites with reduced sensitivity to malaria drugs (artemisinins) have recently emerged. The study will recruit participants from patients who attend the clinic with uncomplicated malaria and asymptomatically infected individuals. Participants are treated with conventional artemisinin-combination therapies (ACT) as part of standard clinical care. From this population, we will select P. falciparum gametocyte carriers. Before, during and after ACT treatment, the transmission potential of artemisinin resistant and wild type infections will be assessed by microscopy, molecular methods, parasite culture and mosquito feeding assays. Parasite clearance will be determined in the first days (d0-3) after treatment. The study population will consist of passively recruited patients with uncomplicated P. falciparum malaria and asymptomatically infected individuals who are microscopy positive for gametocytes. Participants will be treated with conventional therapies for uncomplicated malaria without randomization: artemether-lumefantrine (AL) or dihydroartemisinin-piperaquine (DHA-PPQ). All doses are supervised. Parasite clearance is assessed ex vivo by ring-stage survival assays and by daily slides during the first days of treatment. Gametocyte carriage and gametocyte commitment/production will be determined for resistant and wild type infections before, during and after treatment. In addition, venous blood will be collected at three timepoints to assess transmission to mosquitoes before (d0), during (d2) and after treatment (d7). The total duration of participation will be 7 days, the primary endpoint will be the reduction in mosquito infection rates at d2 (artemether-lumefantrine) or d7 (dihydroartemisinin-piperaquine) compared to pre-treatment.

Timeline

Start

2024-05-28

Primary completion

2025-11-22

Completion

2025-11-22

Publications

• Results Conrad MD, Asua V, Garg S, Giesbrecht D, Niare K, Smith S, Namuganga JF, Katairo T, Legac J, Crudale RM, Tumwebaze PK, Nsobya SL, Cooper RA, Kamya MR, Dorsey G, Bailey JA, Rosenthal PJ. Evolution of Partial Resistance to Artemisinins in Malaria Parasites in Uganda. N Engl J Med. 2023 Aug 24;389(8):722-732. doi: 10.1056/NEJMoa2211803.
• Results Tumwebaze PK, Conrad MD, Okitwi M, Orena S, Byaruhanga O, Katairo T, Legac J, Garg S, Giesbrecht D, Smith SR, Ceja FG, Nsobya SL, Bailey JA, Cooper RA, Rosenthal PJ. Decreased susceptibility of Plasmodium falciparum to both dihydroartemisinin and lumefantrine in northern Uganda. Nat Commun. 2022 Oct 26;13(1):6353. doi: 10.1038/s41467-022-33873-x.

Drugs

Indications