Controlled Human Malaria Infection (CHMI) After Immunization With Cryopreserved Plasmodium Falciparum Sporozoites Under Chloroquine Prophylaxis

Malaria Clinical Trial

Official title: Controlled Human Malaria Infection (CHMI) After Immunization With Cryopreserved Plasmodium Falciparum Sporozoites Under Chloroquine Prophylaxis

Status Completed

Clinical Trial Summary

The purpose of the study is to determine the safety and tolerability of ID administration of PfSPZ Challenge to volunteers taking chloroquine chemoprophylaxis (an approach called PfSPZ-CVac).

Clinical Trial Description

The study is a single centre, double blind, randomized controlled clinical trial. Volunteers, investigators and laboratory personnel will be blinded.

A maximum of 30 volunteers will be randomly divided into four groups. All volunteers will receive standard weekly chloroquine chemoprophylaxis for a period of 14 weeks (98 days). During this period, groups 1 and 3 will receive six ID injections of PfSPZ Challenge, containing a total of 75,000 PfSPZ of the Pf NF54 strain, on days 8, 36 and 64 (immunizations 1, 2 and 3). The control groups 2 and 4 will receive ID injections with normal saline (NS) on the same days.

Thirty-three days after the last dose of chloroquine, volunteers in groups 1 and 2 will have controlled human malaria infection (CHMI) by the bites of five mosquitoes infected with PfSPZ of the Pf NF54 strain. If ≥75% of volunteers in group 1 are protected against this homologous Pf CHMI, volunteers in groups 3 and 4 will have CHMI by the bites of five mosquitoes infected with the heterologous Pf NF135.C10 strain 75 days after the last dose of chloroquine.

If <75% of volunteers in group 1 are protected against the homologous Pf CHMI, volunteers in groups 3 and 4 will receive an additional immunization (immunization 4), which will consist of six ID injections on the same day of 75,000 PfSPZ Challenge and NS respectively, at day 162. In this fourth immunization period chloroquine will be administered for another 6 weeks starting at day 154. Finally, 33 days after the last dose of chloroquine, volunteers in groups 3 and 4 will have homologous Pf CHMI by the bites of five PfSPZ-infected mosquitoes.

After CHMI all volunteers will be treated with a curative regimen of Malarone® (each tablet containing 250 mg atovaquone and 100 mg proguanil), either at the time of detection of blood stage parasitemia or 21 days after exposure to PfSPZ-infected mosquitoes. Volunteers will be checked for parasites by thick smear at least twice after treatment.

If one of the volunteers is not fit to participate in the study on day -1, an alternate volunteer who passed screening will replace him or her. For this purpose 3 additional volunteers will be screened for possible back up. ;

Related Conditions & MeSH terms

• Malaria
• Plasmodium Falciparum

• NCT number: NCT01728701
• Study type: Interventional
• Source: Sanaria Inc.
• Status: Completed
• Phase: Phase 1
• Start date: September 2012
• Completion date: February 2014