Controlled Human Malaria Infection by Intradermal Injection of Plasmodium Falciparum Sporozoites (PfSPZ Challenge)in Tanzanian Adults
Overview
- Phase
- Phase 1
- Intervention
- Not specified
- Conditions
- Malaria
- Sponsor
- Sanaria Inc.
- Enrollment
- 30
- Locations
- 1
- Primary Endpoint
- Number of volunteers positive in each group through day 28 of follow up.
- Status
- Completed
- Last Updated
- 11 years ago
Overview
Brief Summary
The proposed trial will evaluate whether relatively non immune populations in endemic countries can be effectively infected with aseptic, purified, cryopreserved sporozoites (PfSPZ Challenge) given intradermally.
Detailed Description
Controlled human malaria infection (CHMI) is a critical component of malaria vaccine and drug development and is an important element of any strategy for accelerating the development of new tools for malaria control, elimination and eradication. Until now, CHMI has been performed in malaria naïve subjects from countries not endemic for malaria using both infectious mosquitoes and recently, aseptic, purified, cryopreserved Plasmodium falciparum sporozoites (PfSPZ). Results from these studies report significant infection success in all study subjects and an excellent safety profile. The conduct of CHMI studies in malaria endemic populations will allow early understanding of responses to new vaccines and drugs in endemic country populations and for direct comparisons between previously exposed and non-exposed individuals. Performing CHMI studies in malaria endemic countries will reduce associated costs, speed-up the process of testing and substantially contribute to the acceleration of the malaria vaccine and drug research and development processes. This study to be conducted in Bagamoyo, Tanzania, aims to see whether people in endemic countries with minimal previous history of malaria are suitable for CHMI using PfSPZ Challenge. This study will also assess whether the success rate of the experiment is improved by lowering the volume of injection and increasing the number of inoculations. Hence, the study will contribute towards improvements in the CHMI studies using syringe and needle inoculation of sporozoites.
Investigators
Eligibility Criteria
Inclusion Criteria
- •Healthy Male aged between 20-35 years, healthy volunteers
- •Good Health status based on history \& clinical examination
- •Residing in or near DaresSalaam
- •Willing to contribute to science in Tanzania
- •Free from malaria parasite by blood smear \& qRT-PCR
- •Not suffering from any chronic illness including HIV/AIDS
- •No documented history of malaria infection for the past 5 yrs
- •Able \& willing to come for complete one year follow up including minimum of three weeks of hospitalization
- •All volunteers must sign the informed consent form \& answer correctly 15 out 15 questions demonstrating their understanding of the meaning \& procedures of the study
- •Volunteer agrees to inform study doctor \& agrees to release medical information concerning contra-indications for participation in the study
Exclusion Criteria
- •History of malaria in the past 5 yrs
- •Plans to travel outside the Dar-es-salaam or Coast Region in first month (day 0-28) of the study
- •Plans to travel to highly malarious areas in the 6 months following the study period
- •Previous participation in malaria vaccine study \&/or positive serology for Plasmodium falciparum asexual crude extract antibodies above acceptable cut off established for the site.
- •History of arrhythmias or prolonged QT-interval or other cardiac disease
- •Positive family history of in the 1st \& 2nd degree relative for cardiac disease \<50 yrs old.
- •Volunteers unable to read \& write in English \& give written informed consent
- •Previous history of drug or alcohol abuse interfering with normal social function
- •A history of psychiatric disease
- •The use of chronic immunosuppressive drugs, antibiotics, or other immune modifying drugs within three months of study onset (inhaled \& topical corticosteroids are allowed) \& during the study period
Outcomes
Primary Outcomes
Number of volunteers positive in each group through day 28 of follow up.
Time Frame: 5 to 28 days
Thick smears will be performed according to a standard operating procedure. In short, 15 μL of whole blood will be distributed on standardized 3-well slides, providing an equal slide thickness for all smears. Slides are dried and stained with Giemsa. 200 fields per slide will be read at 1000X. Slides are considered positive if they contain 2 or more parasites per 200 fields.
Secondary Outcomes
- Time from inoculation until first positive parasitemia by thick smear in each volunteer in the two groups.(5-28 days)
- Time from inoculation to until first positive parasitemia by qRT-PCR in each volunteer in the two groups.(5-28 days)
- Kinetics of parasitemia in positive volunteers in the two groups as measured by qRT-PCR.(5-28 days)
- Occurrence or intensity of signs or symptoms in the two groups of volunteers(5 days to 6 months)