study to assess efficacy of new malaria vaccine candidates adch63 ama1, mva ama1, adch63 msp1, mva msp1, adch63 me-trap & mva me-trap

Conditions: Malaria

Summary: this study aims to test the safety and efficacy of six new malaria vaccines - adch63 ama1, mva ama1, adch63 msp1, mva msp1, adch63 me-trap \& mva me-trap. these vaccines consist of inactivated viruses which have been modified - so they cannot reproduce (replicate) in humans, and also to include genetic material (genes) for malaria proteins which are expressed by the malaria parasite during both liver and blood stage infection. the vaccines are designed to stimulate an immune response to these malaria proteins (immunogenicity describes the nature and magnitude of this immune response) and thus provide protection against malaria infection. the protective efficacy of vaccines will be evaluated by challenging a small number of volunteers who have received the vaccines with malaria infection from the bites of infected mosquitos(sporozoite challenge).


Eligibility criteria:
inclusion criteria: * healthy adults aged 18 to 50 years * able and willing (in the investigator's opinion) to comply with all study requirements * willing to allow the investigators to discuss the volunteer's medical history with their general practitioner * for female volunteers, willingness to practice continuous effective contraception for the duration of the study. * agreement to refrain from blood donation during the course of the study * written informed consent exclusion criteria: * history of clinical p. falciparum malaria * travel to a malaria endemic region during the study period or within the preceding six months with a risk of malaria exposure. * participation in another research study involving an investigational product in the 30 days preceding enrolment, or planned use during the study period. * prior receipt of an investigational malaria vaccine or any other investigational vaccine likely to impact on interpretation of the trial data * administration of immunoglobulins and/or any blood products within the three months preceding the planned administration of the vaccine candidate * any confirmed or suspected immunosuppressive or immunodeficient state, including hiv infection; asplenia; recurrent, severe infections and chronic (more than 14 days) immunosuppressant medication within the past 6 months (inhaled and topical steroids are allowed) * pregnancy, lactation or intention to become pregnant during the study * contraindication to both anti-malarial drugs; riamet \& chloroquine * concomitant use with other drugs known to cause qt-interval prolongation (e.g. macrolides, quinolones, amiodarone etc) * history of epilepsy * history of arrhythmia or prolonged qt interval. * family history for sudden cardiac death. * an estimated, ten year risk of fatal cardiovascular disease of ≥5%, as estimated by the systematic coronary risk evaluation (score) system 107 * history of allergic disease or reactions likely to be exacerbated by any component of the vaccine e.g. egg products, kathon. * history of clinically significant contact dermatitis * any history of anaphylaxis post vaccination * history of cancer (except basal cell carcinoma of the skin and cervical carcinoma in situ) * history of serious psychiatric condition that may affect participation in the study * any other serious chronic illness requiring hospital specialist supervision * suspected or known current alcohol abuse as defined by an alcohol intake of greater than 42 units every week * suspected or known injecting drug abuse in the 5 years preceding enrolment. * seropositive for hepatitis b surface antigen (hbsag) * seropositive for hepatitis c virus (antibodies to hcv) * any clinically significant abnormal finding on biochemistry or haematology blood tests or urinalysis * any other significant disease, disorder or finding which may significantly increase the risk to the volunteer because of participation in the study, affect the ability of the volunteer to participate in the study or impair interpretation of the study data.

Keywords: vaccine safety immunogenicity protection sporozoite challenge