Phase I/II Trial of a Malaria Vaccine in Adults Living in the United States of America

• Controlled challenge, Phase I/IIa WRAIR study.
• Healthy, malaria-naive adults aged 18 - 50 years.
• 2 groups, 5 subjects in group A (10µg dose) and 15 subjects in group B (50µg dose).
• Control: none for immunization phase; infectivity controls for challenge and rechallenge phases. Six infectivity controls per day of challenge will be enrolled for the challenge phases, with 3 alternates available for challenge if needed.
• Vaccination schedule of 0, 1 months.
• Challenge of up to 15 subjects in Group B.
• Contingent upon short term efficacy, rechallenge of initially protected subjects 6 months (+/- 2 months) after second dose of vaccine.
• Self-contained study.
• Duration of the study, per subject: approximately 15 months (screening, enrollment, vaccination, challenge and rechallenge).
• Data collection will be by done at the site.

Inclusion criteria

• A male or non-pregnant female 18 to 50 years of age (inclusive) at the time of screening.
• Written informed consent obtained from the subject before screening procedures.
• Free of obvious health problems as established by medical history and clinical examination before entering into the study.*
• Available to participate for duration of study (approximately 15 months).
• If the subject is female, she must be currently using birth control, must be surgically sterilized, or must be at least 1-year post menopausal.
• Pass a comprehension assessment test.

Exclusion criteria

• Prior receipt of an investigational malaria vaccine.
• Use of any investigational or non-registered drug or vaccine other than the study vaccine(s) within 28 days preceding the first dose of study vaccine, or planned use during the study period.
• Administration of chronic immunosuppressants or other immune modifying drugs within six months of vaccination.
• Chronic use of antibiotics with anti-malarial effects.
• Planned administration/ administration of a vaccine not foreseen by the study protocol within 30 days of the first dose of vaccine(s).
• History of use of anti-malarial medication within 60 days prior to vaccination.
• Any history of malaria.
• Known exposure to malaria within the previous 12 months.
• Planned travel to malarious areas during the study period.
• Any confirmed or suspected immunosuppressive or immunodeficient condition, including HIV infection.
• A family history of congenital or hereditary immunodeficiency.
• History of allergic disease or reactions likely to be exacerbated by any component of the vaccine.
• Chronic or active neurologic disease including seizures, but not including a single febrile seizure as a child.
• History of splenectomy.
• Acute disease at the time of enrollment.
• Acute or chronic, clinically significant pulmonary, cardiovascular, hepatic or renal functional abnormality, as determined by physical examination or laboratory screening tests.
• Personal history of autoimmune disease or subjects who describe a first-degree relative with clearly documented autoimmune disease.
• Seropositive for hepatitis B surface antigen.
• Seropositive for Hepatitis C virus (antibodies to HCV).
• Administration of immunoglobulins and/or any blood products within the three months preceding the first dose of study vaccine or planned administration during the study period.
• Pregnant or lactating female.
• Suspected or known current alcohol abuse as defined by the American Psychiatric Association in DSM IV.
• Chronic or active intravenous drug use.
• History of severe reactions to mosquito bites as defined as anaphylaxis.
• Female who intends to become pregnant during the study.
• Any history of anaphylaxis in reaction to vaccination.
• A clinical history of sickle cell disease or sickle cell trait.
• Any other significant finding that in the opinion of the investigator would increase the risk of having an adverse outcome from participating in this study.