Velocity 2: An Anthrax Vaccine and Antibiotics Clinical Study

This is a Phase 2, open-label, multicenter, randomized trial designed to evaluate the pharmacokinetic profile, immunogenicity, and safety of AV7909 and ciprofloxacin or doxycycline when administered concomitantly in healthy adults for an indication of post-exposure prophylaxis (PEP) of anthrax. Healthy adults between 18 to 45 years of age (inclusive) will sign and date an informed consent form and then be screened for eligibility for participation in the study 2 to 28 days prior to randomization. Participants meeting the entry criteria will be randomized 1:1:1 to one of the three study groups (AV7909 + ciprofloxacin, AV7909 + doxycycline and AV7909 only) on Day 1. Subjects randomized into Groups 1 \& 2 will be assigned to subgroups. Subgroup A will be assigned to the antibiotic PK treatment group first, while subgroup B will be assigned to the antibiotic non-PK treatment group. Participants will be evaluated for safety through Day 51 \[or the early withdrawal visit (EWV)\], as assessed by clinical laboratory tests (hematology, serum chemistry, and urinalysis), monitoring of Adverse Events (AEs) including Serious Adverse Events (SAEs) and Adverse Events of Special Interest (AESIs), vital signs, and physical examinations. Adverse Events of Special Interest are adverse events associated with autoimmune disease as defined by the Center for Biologics Evaluation and Research, and might represent a safety signal for vaccine-associated autoimmunity. Reactogenicity (solicited systemic and injection site reactions) will be assessed daily by the participants using electronic diaries (e-diaries) after each vaccination. The e-diary will also be used to record self-administration of antibiotics for applicable study groups. Information on the use of medications will be collected at each study visit. In addition, blood samples for auto-antibody assessment will be taken at Day 1 pre-dose and Day 51 (or Early Withdrawal Visit). Participants who receive at least one dose of vaccine will also be asked to participate in safety follow-up phone calls occurring on Month 3, Month 6, Month 9, and Month 12 (nominally 3, 6, 9, and 12 months after the last vaccination) to collect information on AEs, SAEs and any potential AESIs. Based on responses at these phone contacts, participants may be asked to return to the clinic for an unscheduled visit to provide blood samples for auto-antibody testing to investigate reports of potential AESIs. Independent safety oversight will be provided by a Data Safety Monitoring Board, which will be notified of significant AEs, potential AEsIs, or any other events as determined by the Medical Monitor, on an ongoing basis.