• Vaccines

Biothrax Generic Name & Formulations

General Description

Anthrax vaccine adsorbed; per 0.5mL dose; susp for IM or SC inj; contains aluminum hydroxide, benzethonium chloride, formaldehyde.

Pharmacological Class

Anthrax vaccine.

How Supplied

Multi-dose vials (5mL)—1


  • Store at 2 °C to 8 °C (36 °F to 46 °F). Do not freeze. Do not use BioThrax after the expiration date printed on the label.

Generic Availability


Mechanism of Action

BioThrax induces antibodies raised against PA that may contribute to protection by neutralizing the activities of the cytotoxic lethal toxin and edema toxin of Bacillus anthracis.

Biothrax Indications


Pre-exposure prophylaxis of disease caused by Bacillus anthracis in high risk persons due to occupation or other activities for anthrax disease. Post-exposure prophylaxis after suspected or confirmed Bacillus anthracis exposure, when given with recommended antibacterial drugs.

Biothrax Dosage and Administration


For IM inj (into the deltoid) or SC inj (over the deltoid) only. Each dose is 0.5mL. 18–65yrs (Pre-exposure): give as IM inj at 0, 1, and 6 months with booster doses at 6 and 12 months after completion of primary series, then at 12-month intervals thereafter; if at risk of hematoma: may give as SC inj at 0, 2, 4 weeks, and 6 months with booster doses at 6 and 12 months after completion of primary series, then at 12-month intervals thereafter; (Post-exposure): give as SC inj at 0, 2, and 4 weeks post-exposure in combination with antimicrobial therapy.


Not established.

Biothrax Contraindications


Severe allergic reaction after a previous BioThrax dose.

Biothrax Boxed Warnings

Not Applicable

Biothrax Warnings/Precautions


Vaccination may not protect all individuals. Have medical treatment and supervision available to manage anaphylactic reactions. History of anthrax disease. Latex allergy. Immunocompromised. Elderly (>65yrs): not indicated. Pregnancy (Cat.D): not recommended. Nursing mothers.


Hypersensitivity Reactions

  • Acute allergic reactions, including anaphylaxis, may occur.

  • Have appropriate medical treatment and supervision available to manage possible anaphylactic reactions after administration.


  • Vial stopper contains natural rubber latex and may cause allergic reactions to patients with a possible history of latex sensitivity.


  • May cause fetal harm when administered to pregnant women.

  • Inform of the potential hazard to a fetus if BioThrax is used during pregnancy, or if the patient becomes pregnancy while taking this drug.

  • Weigh the potential benefits against the potential risk to the fetus. Do not vaccinate pregnant women against anthrax unless the potential benefits outweigh the potential risk.

History of Anthrax Disease

  • Increased potential for severe local adverse reactions in patients with a history of anthrax disease.

Altered Immunocompetence

  • Immune response may be diminished if BioThrax is given to immunocompromised persons, including those receiving immunosuppressive therapy.

Limitations of Vaccine Effectiveness

  • May not protect all individuals.

Pregnancy Considerations

Pregnancy Category D

  • Healthcare practitioners are encouraged to register women who receive BioThrax during pregnancy in Emergent’s vaccination pregnancy registry by calling 1-619-553-9255.

Nursing Mother Considerations

  • It is not known if BioThrax is excreted in human milk.

  • Exercise caution when BioThrax is given to a nursing woman.

Pediatric Considerations

  • Safety and efficacy has not been established.

Geriatric Considerations

  • Not approved for use in patients greater than 65 years of age.

Biothrax Pharmacokinetics

See Literature

Biothrax Interactions


Concomitant other vaccines: inject at different sites. Concomitant immunosuppressants, chemotherapy, high-dose corticosteroids (>2 weeks), radiation therapy: may get sub-optimal response.

Biothrax Adverse Reactions

Adverse Reactions

Tenderness, pain, erythema, edema, limited arm motion, muscle aches, fatigue, headache; allergic reactions.

Biothrax Clinical Trials

Clinical Trials

Pre-Exposure Prophylaxis

Controlled Field Study

  • A controlled field study using an earlier version of a protective antigen-based anthrax vaccine developed in the 1950’s and supplied by G. G. Wright and associates of the U.S. Army Chemical Corps, Fort Detrick, Frederick, MD, that consisted of an aluminum potassium sulfate-precipitated cell-free filtrate from an aerobic culture, was conducted from 1955-1959.

  • During the study, there were 26 cases reported across 4 mills in the northeastern US (5 inhalation and 21 cutaneous).

  • Of the 21 cutaneous cases, 15 were in the placebo arm, 3 were in the observational arm, and 3 received anthrax vaccine.

  • The calculated efficacy of the vaccine to prevent all types of anthrax disease was 92.5% regardless of the route of exposure or clinical manifestations.


  • Between 1962 and 1974, individuals received either BioThrax or the earlier protective antigen-based anthrax vaccine used in the field study described above.

  • Of the 27 reported cases of anthrax, 24 cases occurred in unvaccinated individuals.

  • In vaccinated individuals 1 case occurred after the person had been given 1 dose of anthrax vaccine and 2 cases occurred after individuals had been given 2 doses of anthrax vaccine. 

  • There were no documented cases of anthrax for individuals who received at least 3 doses of the originally licensed 6-dose series of anthrax vaccine.

Prospective Study

  • Between 2002 and 2007, a prospective double-blinded, randomized, placebo-controlled and active-controlled study was conducted to evaluate the impact on safety and immunogenicity on changing the administration route from SC to IM, and reducing the number of doses. This study included 1564 healthy men and women 18 to 61 years of age. Patients were randomly assigned to 1 of 6 groups (see full labeling). 

  • Immunoglobulin G (IgG) antibodies directed against anthrax protective antigen (PA) were measured using ELISA at the Week 8 and Months 7, 13, 19, 31, and 43 time points. The 3 primary immunogenicity endpoints were: (1) Geometric Mean Concentraion (GMC) (mcg/mL), (2) Geometric Mean Titer (GMT), and (3) percentage with 4-fold rise in anti-PA antibody titer from baseline.

  • To compare the originally licensed 6-dose SC schedule (0, 2, 4 weeks and 6, 12, and 18 months) versus a 3-dose IM primary series (at 0, 1, and 6 months), non-inferiority analyses were performed for all three primary immunogenicity endpoints.

  • Noninferiority was shown for all analyses supporting a 3 dose primary series of BioThorax administered IM at 0, 1, and 6 months followed by booster doses at 12 and 18 months and at 1-year intervals to maintain protective immunity.

  • Noninferiority was also shown supporting a 4 dose SC primary series of BioThorax administered at Weeks 0, 2, 4, and at 6 months followed by booster doses at 12 and 18 months after initiation, and at 1-year intervals to maintain protective immunity.


Post-Exposure Prophylaxis

  • A clinical study evaluated the post-exposure SC administration schedule of BioThorax in healthy adults following 3 doses at 0, 2, and 4 weeks. The primary immunogenicity endpoint was the proportion of subjects achieving a threshold TNA NF50 value ≥0.56 at Day 63, 5 weeks after the third vaccination. 

  • 71.2% of patients achieved NF50 value ≥0.56 at Day 63 and the lower bound of the 95% CI was 64.1%.

  • In a separate analysis of this clinical study using the threshold associated with a 70% probability of survival in nonhuman primates (NHP), 93.5% of patients achieved NF50 value ≥0.29 at Day 63. The lower bound of the 95% CI was 88.9%.


Non-Interference of Post-Exposure Prophylaxis Vaccination and Antimicrobials When Used Concurrently

  • In an open-label study, the potential impact of 0.5mL of BioThorax administered SC at 0, 2, and 4 weeks was evaluated on the pharmacokinetics of ciprofloxacin in 154 healthy adult male and female patients. The potential impact of ciprofloxacin was also evaluated on the immunogenicity of BioThorax 2 weeks after the last BioThorax dose.

  • Concomitant use of BioThorax SC with oral ciprofloxacin did not alter the pharmacokinetics of ciprofloxacin, and vice versa.

Biothrax Note


Register pregnant patients in the Vaccine pregnancy registry by calling (619) 553-9255.

Biothrax Patient Counseling

Patient Counseling

  • Advise women of the potential risk to the fetus. Encourage women who are exposed to BioThrax during pregnancy to inform their healthcare provider and enroll in the BioThrax (Anthrax) Vaccine in Pregnancy Registry (Phone: 1-619-553-9255).

  • Inform patients of the benefits and risks of immunization with BioThrax. 

  • Instruct patients to report any serious adverse reaction to their health care provider.