JNJ-42721458

JNJ-42721458 is a human monoclonal antibody (IgG1) developed for the prophylaxis and treatment of **inhalational anthrax**. Developed by **Janssen Research & Development** (a subsidiary of **Johnson & Johnson**), the antibody specifically targets the **Protective Antigen (PA)** of *Bacillus anthracis*. Protective Antigen is a critical component of the tripartite anthrax toxin; it binds to host cell receptors and mediates the entry of lethal factor (LF) and edema factor (EF) into the cytoplasm. By binding to PA, JNJ-42721458 prevents the formation of the toxin pore and subsequent translocation of LF and EF, thereby neutralizing the lethal and edema toxins that cause the severe pathophysiology of anthrax. The drug has been evaluated in **Phase 1** clinical trials to assess its safety, tolerability, and pharmacokinetics following single and multiple subcutaneous doses in healthy volunteers.