New anthrax injection available

FDA approved obiltoxaximab injection, (Anthim, Elusys Therapeutics), to treat inhalational anthrax.

Anthim treats inhalational anthrax due to Bacillus anthracis in combination with appropriate antibacterial drugs, and for prophylaxis of inhalational anthrax when alternative therapies are not available or are not appropriate.

“As preparedness is a cornerstone of any bioterrorism response, we are pleased to see continued efforts to develop treatments for anthrax,” said Edward Cox, MD, director of the Office of Antimicrobial Products in FDA’s Center for Drug Evaluation and Research.

Related: Treatment for inhalational anthrax approved

Anthim should only be used for prophylaxis when its benefit for prevention of inhalational anthrax outweighs the risk of hypersensitivity and anaphylaxis. Anthim is supplied as single-dose vials for intravenous (IV) infusion.

Anthim is a monoclonal antibody that neutralizes toxins produced by B anthracis. Anthim’s toxin neutralizing activity prevents entry of anthrax toxin into susceptible cells, avoiding further spread of the toxin throughout the body and the ensuing tissue damage that leads to death.

Anthim was approved under FDA’s Animal Rule, which allows efficacy findings from adequate and well-controlled animal studies to support FDA approval when it is not feasible or ethical to conduct efficacy trials in humans.

Anthim monotherapy administered as a single 16 mg/kg IV dose for the treatment of inhalational anthrax disease resulted in statistically significant improvement in survival relative to placebo in 2 studies for each species. Anthim administered in combination with antibacterial drugs (levofloxacin, ciprofloxacin and doxycycline) for the treatment of systemic inhalational anthrax disease resulted in higher survival outcomes than antibacterial therapy alone in multiple studies where Anthim and antibacterial therapy was given at various doses and treatment times.

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And Anthim administered as prophylaxis resulted in higher survival outcomes compared to placebo in multiple studies where treatment was given at various doses and treatment times.

Plus, the safety of Anthim was evaluated in 320 healthy human volunteers. The most frequently-reported side effects were headache, itching (pruritus), upper respiratory tract infections, cough, nasal congestion, hives, and bruising, swelling and pain at the infusion site.

However, Elusys warned that there have been no studies of the safety or pharmacokinetics (PK) of Anthim in the pediatric population. “Dosing in pediatric patients was derived using a population PK approach,” the company said in a statement.

In addition, Anthim does not have direct antibacterial activity, so it should be used in combination with appropriate antibacterial drugs. Anthim is not expected to cross the blood-brain barrier and does not prevent or treat meningitis.

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