FDA approves Anthim (obiltoxaximab) for anthrax- Elusys Therapeutics

The FDA has approved Anthim (obiltoxaximab) Injection, from Elusys Therapeutics, a monoclonal antibody (mAb) anthrax antitoxin. Anthim is indicated in adult and pediatric patients for the treatment of 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. Anthim should only be used for prophylaxis when its benefit for prevention of inhalational anthrax outweighs the risk of hypersensitivity and anaphylaxis.

The effectiveness of Anthim is based solely on efficacy studies in animal models of inhalational anthrax. 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. Anthim does not have direct antibacterial activity. Anthim 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.

Because it is not feasible or ethical to conduct controlled clinical trials in humans with inhalational anthrax, the efficacy of Anthim for the treatment of inhalational anthrax is based on efficacy studies in two animal models. The animal efficacy studies are conducted under widely varying conditions, such that the survival rates observed in the animal studies cannot be directly compared between studies and may not reflect the rates observed in clinical practice.