CompletedPhase 2

Evaluation of Reproducibility of a Sporozoite Challenge Model for Plasmodium Vivax in Human Volunteers

Colombia18 participantsStarted 2006-12

Plain-language summary

The study is a randomized open label clinical trial to verify the reproducibility of a sporozoite challenge model for Plasmodium vivax in humans. The verification of the reproducibility of such a model will make it possible to evaluate the efficacy of candidate P. vivax vaccines in Phase 2a trials. The study is divided into two successive steps: Step A Parasite Blood Donation: Volunteers will be recruited passively from a group of patients who present with active P. vivax infection and accept to donate infected blood. Samples of P. vivax infected blood will be collected and will be screened for infectious diseases, according to standard blood bank procedures. Colonized Anopheles albimanus mosquitoes will be fed with this blood using a Membrane Feeding Assay (MFA). Sixteen (16) days after, selected positive mosquito batches will be used for step B. Step B Challenge: After informed consent signature, a total of 18 healthy volunteers will be randomly allocated to Groups 1, 2 and 3, of 6 volunteers each and will be challenged with the bite of 3±1, P. vivax infected mosquitoes. Each group will be exposed to a different isolated parasite. Volunteers will be closely monitored post infection, and will be treated as soon as blood infection becomes patent as ascertained by microscopic examination of thick blood smears (TBS). Comparison of data obtained in the three different groups will be used to determine reproducibility of challenge model. Primary objective: To demonstrate that naïve human volunteers can be safely and reproducibly infected by the bite of An. albimanus mosquitoes carrying P. vivax sporozoites in their salivary glands. Secondary objective: To determine the influence of the type of parasite isolated on reproducibility and safety of the challenge model with P. vivax in human volunteers Hypothesis:It is possible to safely develop a reproducible P. vivax infection in human volunteers using P. vivax experimentally infected An. albimanus mosquitoes.

Who can participate

Age range18 Years – 45 Years

SexALL

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AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion Criteria: * Healthy, adult male or non-pregnant females (18-45 years of age). * Capacity to sign a free informed consent form of participation along with two witnesses. * Use of adequate contraceptive method from the initiation of the study until three months after sporozoite challenge. * No plans to travel to malaria endemic areas during the course of the study (a year). * No plans to travel outside the study area from the 7th day until 31st day after the challenge. * Reachable by phone during the whole study period. * Able to participate during the whole study period. Exclusion Criteria: * Are less than 18 and over 45 years of age. * Are female who is pregnant at serum positive B-HCG screening, planning to become pregnant or who is nursing. * Have a Duffy negative phenotype. * Have a G-6-PD deficiency or any other hemoglobinopathy. * Current or past infection with any species of malaria as demonstrated by a positive TBS on screening or history of a documented positive blood smear. P. vivax IFAT of 1 * Have a known history of allergy to antimalarial drugs or immediate type hypersensitivity reactions to mosquito bites. * Clinical or laboratory evidence of significant systemic disease, including hepatic, renal, cardiac, immunologic or hematological disease, HIV positive or have any other known immunodeficiency (including receiving immunosuppressive therapy or a history of splenectomy); infected with hepatitis B or C virus; have a history of autoimmune disease (inc…

What they're measuring

Infection for P. Vivax

Timeframe: Twenty eight days

Trial details

NCT IDNCT00367380

SponsorMalaria Vaccine and Drug Development Center

Sponsor typeOTHER

Study typeINTERVENTIONAL

Primary completion2006-12

Results submitted2014-03-27