VELOCITY: An Anthrax Vaccine Clinical Study

This is a Phase 3, multicenter, randomized, double-blind, parallel-group trial designed to
evaluate the lot consistency (using three consecutively manufactured lots), immunogenicity,
and safety of AV7909 administered in healthy adults for an indication of postexposure
prophylaxis (PEP) of anthrax.

Healthy adults between 18 and 65 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 2:2:2:1 to
one of four study groups on Day 1. Randomization will be stratified by site.

Participants will be evaluated for safety through Day 64 [or the early withdrawal visit
(EWV)], as assessed by clinical laboratory tests (hematology, serum chemistry, and
urinalysis), monitoring of Adverse Events (AE) including Serious Adverse Events (SAE) and
Adverse Events of Special Interest (AESI), 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.

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 predose and Day 64 (or
Early Withdrawal Visit).

Participants who receive at least one dose of vaccine but who for any reason discontinue
vaccinations prematurely will be asked to participate in the further planned study visits up
to Day 64 for safety assessment only.

Participants who receive at least one dose of vaccine will also be asked to participate in
safety follow-up phone calls occurring on Day 43, Month 4, Month 7, Month 10, and Month 13
(nominally 0.5, 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 as determined by the Medical Monitor on an ongoing basis.

Inclusion Criteria:

1. Written informed consent obtained from the participant (dated and signed).

2. Healthy condition as established by medical history and clinical examination before
entering into the study.

3. A male or female aged 18 to 65 years, inclusive, at the time of informed consent.

4. Body mass index (BMI) ≤35.0 kg/m^2 at Screening visit.

5. Have adequate venous access for phlebotomies.

6. For a woman of childbearing potential (WOCBP), negative serum pregnancy test at
Screening and negative urine pregnancy test prevaccination on Day 1, not currently
breastfeeding, and no intention to become pregnant during the study through Month 13.
Every female participant is considered to be a WOCBP unless surgically sterile
(bilateral oophorectomy or bilateral salpingectomy or hysterectomy) OR postmenopausal
(defined as >12 consecutive months without menses and screening follicle-stimulating
hormone >30 mIU/mL). Women who are not of childbearing potential are allowed to enroll
if they are surgically sterile or postmenopausal as defined above.

Exclusion Criteria:

1. Use of any investigational or nonregistered product (drug, vaccine, device, or
combination product) within 30 days preceding the dose of study vaccine, or planned
use during the study through Month 13.

2. Positive test result on urine drug screen, any evidence of ongoing drug abuse or
dependence (including alcohol), or recent history (over the past five years) of
treatment for alcohol or drug abuse.

3. Chronic administration (defined as >14 days) of immunosuppressants or other
immune-modifying drugs (includes oral or parenteral corticosteroids, for example, a
glucocorticoid dose exceeding 10 mg/day prednisone or equivalent) within six months
prior to the vaccine dose; inhalation use (for example, for seasonal allergies) is
permitted.

4. Planned administration of any commercially-available vaccine from seven days prior to
the first study vaccination through two weeks after the last vaccination.

5. Previous anaphylactic reaction, severe systemic response, or serious hypersensitivity
to a prior immunization or a known allergy to synthetic Oligodeoxynucleotides,
aluminum, formaldehyde, benzethonium chloride (phemerol), or latex.

6. History of anthrax disease, suspected exposure to anthrax, or previous vaccination
with any anthrax vaccine.

7. Have a tattoo/scar/birthmark or any other skin condition affecting the deltoid area
that may interfere with injection site assessments.

8. A positive blood test for hepatitis B surface antigen, hepatitis C antibody, or human
immunodeficiency virus (HIV) HIV-1 or HIV-2 antibodies.

9. Any confirmed or suspected immunodeficiency condition (congenital or secondary) or
autoimmune disease based on medical history and Physical Exam, for example,
Guillain-Barré.

10. A family history of congenital or hereditary immunodeficiency.

11. Major congenital defects or serious chronic illness, including any cancer other than
the following: a) any non-metastatic cancer (excluding hematologic malignancies) or
melanoma of which the participant has been disease-free for at least five years and b)
localized skin cancer, resected (including squamous cell and basal cell carcinomas).

12. Acute disease at the time of enrollment. Note that screening lab tests may be delayed
to allow the resolution of a transient acute condition or the subject may be
rescreened.

13. Any medical condition that, in the opinion of the investigator, could adversely impact
the participant's participation or the conduct of the study.

14. Any planned elective surgery during the study through 12 months after the last
vaccination.

15. Planned receipt of immunoglobulins and/or any blood products within the three months
preceding study enrollment or at any point during the study period until after the
final safety phone contact.

16. Woman of childbearing potential refusing to practice an adequate method of
contraception from at least one month before Day 1 and continuing through Month 13.

An adequate method of contraception is defined as abstinence from sexual intercourse;
prior bilateral tubal ligation; monogamous relationship with a vasectomized partner
(vasectomy performed at least six months prior to the participant's screening visit);
or any of these forms of birth control: pill, intrauterine device (IUD), implantable
or injectable contraceptive (for example, Norplant® or Depo-Provera®), removable
device (for example, NuvaRing® or Evra® patch), or double-barrier method (condom with
spermicide, diaphragm with spermicide). The Principal Investigator and/or designee
will discuss with the participant the need to use adequate contraception consistently
and correctly and document such conversation in the participant's chart. In addition,
the Principal Investigator and/or designee will instruct the participant to call
immediately if the selected contraception method is discontinued or if pregnancy is
known or suspected.

17. Member or family member of the investigator site team.

18. Previously served in the military any time after 1990 and/or plan to enlist in the
military at any time from screening through the final telephone contact.