Anthrax AV7909 Boost Evaluation Study

Inclusion Criteria:

1. Male or non-pregnant females, 18 through 65 years of age, inclusive.

2. Willing and able to provide written informed consent prior to initiation of studyprocedures.

3. In relatively stable health, as determined by medical history and physicalexamination. Any chronic medical diagnoses or conditions should be stable and wellmanaged, with no significant changes expected during the study period, and in theopinion of the site investigator, will not impact the ability to assess safetyand/or immunogenicity per the study design.

4. If a female of childbearing potential who is sexually active, agrees to use anacceptable method of birth control from Screening to Day 396 and has used a reliablebirth control method for at least 2 months prior to Screening.

5. Female of childbearing potential is defined as post onset menarche andpre-menopausal person capable of becoming pregnant. This does not includefemales who meet any of the following conditions: a) menopausal >2 years; b)tubal ligation >1 year; c) bilateral salpingo-oophorectomy; or d) hysterectomy.

6. Adequate contraception is defined as a contraceptive method with a failure rateof less than 1% per year when used consistently and correctly and whenapplicable, in accordance with the product label, for example: oralcontraceptives, either combined or progestogen alone; injectable progestogen;implants of etenogestrel or levonorgestrel; estrogenic vaginal ring;percutaneous contraceptive patches; intrauterine device or intrauterine system;the female subject has exclusively female sexual partners; partner is sterileor otherwise unable to produce sperm (information on the person's sterility cancome from the site personnel's review of the subject's medical records orinterview with the subject regarding her medical history); male condom combinedwith a vaginal spermicide (foam, gel, film, cream, or suppository); or malecondom combined with a female diaphragm, either with or without a vaginalspermicide (foam, gel, film, cream, or suppository).

7. Available for all study visits, willing to participate in all study procedures, andnot planning to relocate from the area for the duration of the study.

8. Has a body mass index (BMI) greater than 18.0 and less than 35.0 kg/m2, inclusive

Exclusion Criteria:

1. Has an acute illness, as determined by the site investigator, within 72 hours priorto study IP administration.

• An acute illness that is nearly resolved, with only minor residual symptomsremaining, is allowable if, in the opinion of the site investigator, theresidual symptoms will not interfere with the ability of study staff to assesssafety parameters as required by the protocol.

• If the subject's temperature is above 100.4°F, indicating illness, the subjectmay be re-assessed for eligibility a minimum of 24 hours later.

2. Has a history of severe reactions to components of AV7909.

3. Has a history of anthrax disease, suspected exposure to anthrax, or previousvaccination with any anthrax vaccine.

4. Has recently diagnosed or poorly controlled human immunodeficiency virus (HIV).

5. Has an acute or chronic hepatitis B or hepatitis C infection, as identified throughlaboratory testing.

• A subject who has been effectively treated for hepatitis C, as evidenced by anegative hepatitis C ribonucleic acid (RNA) confirmation test, and who nolonger requires antiviral therapy is not excluded.

6. Is suffering from or has a history of neuralgia, paresthesia, neuritis, convulsions,or encephalomyelitis within 90 days prior to Screening, or a family history ofGuillain-Barré syndrome.

7. Has a history of alcohol or drug abuse within 5 years prior to Screening.

8. Has any diagnosis, current or past, of schizophrenia, bipolar disease, or any otherpsychiatric diagnosis that may, in the opinion of the site investigator, interferewith subject compliance or safety evaluations.

9. Is taking herbal medicines/preparations that are known to have a direct or indirecteffect on the immune system.

10. Presence of tattoos on both upper arms that would cover or partially cover allpotential vaccination sites.

11. Clinically relevant signs of pathology or conduction disturbances documented byelectrocardiogram (EKG).

12. Has taken corticosteroids as follows within 30 days prior to Screening.

• Oral or parenteral corticosteroids at a dose of ≥20 mg daily and/or

• High-dose (>800 mcg/day of beclomethasone di-iso-propionate chlorofluorocarbon [CFC] or equivalent) inhaled corticosteroids.

13. Female of childbearing potential who has a positive urine pregnancy test or who iscurrently breastfeeding.

14. Has had any vaccination (licensed or under Emergency Use Authorization [EUA]; anytype) within the 30 days prior to the planned first study IP administration.

15. Is immunosuppressed due to an underlying disease or medication, use of anticancerchemotherapy (cytotoxic), or radiation therapy.

16. With the exception of basal or squamous cell skin cancer, has known activeneoplastic disease, including hematologic malignancy.

17. Has received an investigational agent within 30 days prior to the planned firststudy IP administration.

18. Has any laboratory test result or clinical findings (including vital signs) thatsingly or in combination are likely to unfavorably alter the risks of subjectparticipation or to confound study safety or immunogenicity results, in the opinionof the site investigator. Additionally, the following are exclusionary:

19. Has any clinically significant Grade 3 laboratory or vital sign result, or anyGrade 4 laboratory or vital sign result (regardless of assessed significance)at Screening.

20. Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) >2 times theupper limit of normal (ULN), or bilirubin >1.5 times the ULN unless isolatedGilbert's syndrome.

21. Creatinine >1.5 times ULN for age and sex.

22. White blood cell count <3,000/µL or >12,500/µL; absolute neutrophil count <1,200/µL; absolute lymphocyte count <750/µL; hemoglobin <10 g/dL females, or <11.5 g/dL males; platelet count <75,000/µL.

23. Hemoglobin A1c (HbA1c) >7.0% at Screening.

24. Has any disease or medical condition that, in the opinion of the site investigator,might confound interpretation of safety or immunogenicity.