About ANTHIM® (obiltoxaximab)

Patient Information

ANTHIM (ˈan(t)-thim) obiltoxaximab injection,
for intravenous use

What is the most important information I should know about ANTHIM?

ANTHIM can cause serious side effects, including:

  • Serious allergic reactions. Tell your healthcare provider right away if you have itching, hives, rash, throat irritation, cough, dizziness, shortness of breath or chest discomfort while receiving ANTHIM.

What is ANTHIM?

  • ANTHIM is a prescription medicine used along with antibiotic medicines to treat people with inhalational anthrax. ANTHIM can also be used to prevent anthrax disease when there are no other treatment options.
  • The effectiveness of ANTHIM has been studied only in animals with inhalational anthrax. There have been no studies in people who have inhalational anthrax.
  • The safety of ANTHIM was studied in healthy adults. There have been no studies of ANTHIM in children younger than 18 years.
  • ANTHIM is not used in prevention or treatment of anthrax meningitis.

Before you receive ANTHIM, tell your healthcare provider about all of your medical conditions, including if you are:

  • allergic to obiltoxaximab or any of the ingredients in ANTHIM. See the end of this leaflet for a list of ingredients in ANTHIM.
  • allergic to diphenhydramine (Benadryl®)
  • pregnant or planning to become pregnant. It is not known if ANTHIM will harm your unborn baby.
  • breastfeeding or plan to breastfeed. It is not known if ANTHIM passes into your breast milk. You and your healthcare provider should decide if you will receive ANTHIM or breastfeed.

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

How will I receive ANTHIM?

  • You will be given 1 dose of ANTHIM by a healthcare provider through a vein (IV or intravenous infusion). It takes about 1 hour and 30 minutes to give you the full dose of medicine.
  • Your healthcare provider should give you a medicine called diphenhydramine (Benadryl®) before you receive ANTHIM to help reduce your chances of developing a skin reaction from ANTHIM. Benadryl may be given to you to take by mouth or through a vein.
  • Benadryl may make you sleepy, and you should use caution if you will be driving or operating equipment.

What are the possible side effects of ANTHIM?

The most common side effects of ANTHIM include headache, itching, upper respiratory tract infections, cough, IV site bruising, swelling and/or pain, stuffy nose (nasal congestion), hives, and pain in the hands or feet. Tell your healthcare provider if you have any side effect that bothers you or that does not go away. These are not all the possible side effects of ANTHIM. For more information, ask your healthcare provider. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. For more information go to dailymed.nlm.nih.gov.

General information about the safe and effective use of ANTHIM.

  • This patient information leaflet summarizes the most important information about ANTHIM. If you would like more information, talk to your healthcare provider. You can ask your pharmacist or healthcare provider for information about ANTHIM that is written for health professionals.

What are the ingredients in ANTHIM?

Active ingredient: Obiltoxaximab

Inactive ingredients: L-histidine, sorbitol and polysorbate 80
Manufactured by: Elusys Therapeutics, Inc., Parsippany, NJ 07054, U.S. License Number 1907. For more information call 1-844-808-0222

The Patient Information has been approved by the U.S. Food and Drug Administration 03/2016



ANTHIM® (obiltoxaximab) is indicated in adult and pediatric patients for the treatment of inhalational anthrax due to Bacillus anthracis in combination with appropriate antibacterial drugs. ANTHIM is indicated for prophylaxis of inhalational anthrax due to B. anthracis when alternative therapies are not available or are not appropriate.


  • ANTHIM should only be used for prophylaxis when its benefit for prevention of inhalational anthrax outweighs the risk of serious hypersensitivity reactions and anaphylaxis.
  • The effectiveness of ANTHIM is based solely on efficacy studies in animal models of inhalational anthrax. It is not ethical or feasible to conduct controlled clinical trials with intentional exposure of humans to anthrax.
  • Safety and PK of ANTHIM have been studied in adult healthy volunteers. There have been no studies of safety or PK of ANTHIM in the pediatric population. A population PK approach was used to derive intravenous infusion dosing regimens that are predicted to provide pediatric patients with exposure comparable to the observed exposure in adults.
  • ANTHIM binds to the protective antigen (PA) component of B. anthracis toxin; it does not have direct antibacterial activity. ANTHIM is not expected to cross the blood-brain barrier and does not prevent or treat meningitis. ANTHIM should be used in combination with appropriate antibacterial drugs.



Hypersensitivity and anaphylaxis have been reported during the intravenous infusion of ANTHIM. Due to the risk of hypersensitivity and anaphylaxis, ANTHIM should be administered in monitored settings by personnel trained and equipped to manage anaphylaxis. Monitor individuals who receive ANTHIM closely for signs and symptoms of hypersensitivity reactions throughout the infusion and for a period of time after administration. Stop ANTHIM infusion immediately and treat appropriately if hypersensitivity or anaphylaxis occurs.


Hypersensitivity reactions were the most common adverse reactions in the safety trials of ANTHIM, occurring in 34/320 healthy subjects (10.6%). Three (0.9%) cases of anaphylaxis occurred during or immediately after the infusion. In clinical trials, manifestations of anaphylaxis were rash/urticaria, cough, dyspnea, cyanosis, postural dizziness and chest discomfort. ANTHIM infusion was discontinued in 8 (2.5%) subjects due to hypersensitivity or anaphylaxis. The adverse reactions reported in these 8 subjects included urticaria, rash, cough, pruritus, dizziness, throat irritation, dysphonia, dyspnea and chest discomfort. The remaining subjects with hypersensitivity had predominantly skin-related symptoms such as pruritus and rash, and 6 subjects reported cough.

Premedication with diphenhydramine is recommended prior to administration of ANTHIM. Diphenhydramine premedication does not prevent anaphylaxis, and may mask or delay onset of symptoms of hypersensitivity.


The safety of ANTHIM has been studied only in healthy volunteers. It has not been studied in patients with inhalational anthrax. The most frequently reported adverse reactions (occurred in >1.5% of healthy subjects) were headache, pruritus, infections of the upper respiratory tract, cough, vessel puncture site bruise, infusion site swelling, urticaria, nasal congestion, infusion site pain, and pain in extremity.


No adequate and well-controlled studies in pregnant women were conducted. Because animal reproduction studies are not always predictive of human response, ANTHIM should be used during pregnancy only if clearly needed.

Pediatric Use
There have been no studies of the safety or PK of ANTHIM in the pediatric population.

To see the complete prescribing information for ANTHIM, click here.