Phase I Study of West Nile Virus Vaccine

This study will test the safety of an experimental vaccine for preventing West Nile virus infection. The virus is spread mainly by mosquito bites. Symptoms can include high fever, headache, neck stiffness, stupor, muscle weakness, vision loss, numbness and paralysis. Rarely, infection leads to permanent nerve damage and possibly death. The vaccine used in the study is made from DNA that codes for West Nile virus proteins. Injected into a muscle, the DNA instructs the body to make a small amount of West Nile virus protein. This study will see if the body creates resistance or immunity to these proteins. Participants cannot get West Nile virus from the vaccine. Healthy normal volunteers between 18 and 65 years of age may be eligible for this study. Candidates are screened with a medical history, physical examination, and blood and urine tests for various infections and other medical problems. Women who are able to become pregnant are given a pregnancy test. Women who are pregnant or breastfeeding may not participate. Anyone who has received a vaccination for Yellow Fever or Japanese Encephalitis virus in the past may not participate in this research study. Participants will receive three injections of the experimental vaccine, the first on the first study day (Day 0), the second on Day 28, and the third on Day 56. The injections are given with a device called Biojector® (Registered Trademark) 2000 that delivers the vaccine through the skin into the muscle without the use of a needle. On the day of each injection, subjects are given a diary card to take home for recording their temperature and any symptoms or side effects for 5 days. They return to the clinic 2 weeks after each injection, bringing the completed card with them at that time. In addition to the injections, subjects have the following tests and procedures during clinic visits: * Medical history and, if needed, physical examination: Day 0 and weeks 2, 4, 6, 8, 10, 12, 24 and 32 * Vital signs and weight: Day 0 and weeks 2, 4, 6, 8, 10, 12, 24 and 32 * Lymph node exam: Day 0 and weeks 2, 4, 6, 8, 10, and 12 * Blood samples: Day 0 and weeks 2, 4, 6, 8, 10, 12, 24 and 32 * Pregnancy test (for women): Day 0 and weeks 4, 8 and 32 * Urine sample: Day 0 and weeks 2, 4, 6, 8, and 10 The blood and urine tests are for health checks. Some blood samples are also used to study the immune response to the vaccine and for gene testing.

Study Design: This is a Phase I open-label study to evaluate safety, tolerability, and immunogenicity of a recombinant DNA vaccine, VRC-WNVDNA020-00-VP. The hypothesis is that this regimen will be safe for human administration and elicit a higher titer of neutralizing antibody response than a prior WNV DNA vaccine. The primary objectives are to evaluate the safety and tolerability in humans of the investigational vaccine in healthy young adults and in healthy older adults. Secondary and exploratory objectives are related to the immunogenicity of the study vaccine. Product Description: VRC-WNVDNA020-00-VP is composed of a single closed-circular DNA plasmid that encodes the WNV viral protein precursor transmembrane (prM) and envelope (E) with a CMV/R promoter. Vaccine vials will be supplied at 4 mg/mL. Each DNA vaccination will be 1 mL of vaccine administered intramuscularly (IM) in the deltoid muscle using the Biojector 2000 Needle-Free Injection Management System (Biojector). Subjects: A total of 30 healthy adults will be enrolled in two groups: Group 1 will be comprised of 15 healthy adults 18 to 50 years old and Group 2 will be comprised of 15 healthy adults 51 to 65 years old. Study Plan: All subjects will receive 3 injections on the schedule shown in the schema. The protocol requires nine clinic visits and three telephone follow-up contacts. Study Duration: 32 weeks of clinical follow up for each participant. A long-term follow-up contact at Week 52 may include interim medical history and research blood draw; or subject may opt for the long-term contact to occur by telephone, e-mail or mail for the interim medical history only. Study Endpoints: The primary endpoint is safety and tolerability of the regimen. The secondary immunogenicity endpoints are WNV neutralizing antibody, WNV specific antibody as measured by ELISA, WNV-specific T cell responses measured by intracellular cytokine staining (ICS) assay and ELISPOT. Other immunogenicity assays through Week 32 may also be completed as exploratory evaluations, as well as from the Week 52 blood samples if collected.