This is a single-center, open label study. The primary aim of this project is to develop a controlled human malaria infection transmission model ("CHMI-trans") or "challenge model" to evaluate the capacity of vaccines, biologics (monoclonal antibodies, or mAbs), and drugs to block malaria parasite transmission by assessing infectiousness of Plasmodium falciparum (Pf) gametocyte carriers for Anopheles mosquitoes.
A total of 32 volunteers will be randomly assigned to four groups (n=8) and subjected to a standard controlled human malaria infection (CHMI) delivered by five Pf-infected mosquitoes (3D7 clone). Treatment is subsequently initiated to induce gametocytaemia (treatment 1, DT1) and to clear pathogenic asexual parasites whilst leaving gametocytes unaffected (treatment 2, DT2). At the end of the study, treatment of all parasite stages is provided following national treatment guidelines (end treatment, ET). Once malaria infections are detected by 18S qPCR positive (day of treatment 1 \[DT1\]), groups 1 and 2 will be treated with a course of subcurative sulfadoxine-pyrimethamine (SP) (SP low, 500mg/25mg). Groups 3 and 4 will receive piperaquine (Pip) in a low-dose (Pip low, 480 mg). After DT1, volunteers will receive a curative treatment (DT2) when a recrudescence of asexual parasitaemia occurs or on day 21 post challenge infection, whichever comes first. Volunteers in group 1 (SP low/SP high) will be treated with sulfadoxine-pyrimethamine (1000mg/50mg) and group 2 (SP low/Pip high) with piperaquine (960mg). Volunteers in group 3 (Pip low/Pip high) will be treated with piperaquine (960mg) and group 4 (Pip low/SP high) with sulfadoxine-pyrimethamine (1000mg/50mg). To ensure the radical clearance of all parasite stages, all volunteers will receive a final treatment (ET) according to national guidelines with atovaquone/proguanil (Malarone®) on day 42. Daily blood samples will allow detailed quantification of gametocytes, gametocyte sex ratio and ex vivo assessments of gametocyte fitness.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
NONE
Enrollment
29
\- subcurative regimen (500mg/25mg)
\- subcurative regimen (480 mg)
\- curative regimen (1000mg/50mg)
Radboud university medical center
Nijmegen, Gelderland, Netherlands
Frequency and magnitude of adverse events in the CHMI-trans model in study groups
Frequency and magnitude of adverse events in the CHMI-trans model in study groups.
Time frame: up to day 42 after challenge infection
gametocyte prevalence
Prevalence of gametocytes in the CHMI-trans model in study groups.
Time frame: up to day 42 after challenge infection
peak density gametocytes
Peak density and time-point of peak density of gametocytes by qRT-PCR.
Time frame: up to day 42 after challenge infection
AUC gametocytes
The area under the curve of gametocyte density versus time.
Time frame: up to day 42 after challenge infection
Gametocyte sex-ratio
ratio of male-female gametes
Time frame: up to day 42 after challenge infection
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\- curative regimen (960 mg)
malaria challenge infection by P. falciparum 3D7-infected mosquito bites
\- curative regimen: 1000/400 mg, for 3 days