BX004

BX004 is BiomX's investigational, nebulized fixed three-bacteriophage cocktail for chronic pulmonary *Pseudomonas aeruginosa* infection in people with cystic fibrosis. The phages are intended to selectively infect, replicate within, and lyse susceptible *P. aeruginosa* cells, thereby lowering bacterial burden in the airways. BX004-A was evaluated in a Phase 1b/2a study, and BiomX subsequently initiated a Phase 2b study; however, BiomX discontinued the Phase 2b cystic-fibrosis trial on December 8, 2025, following Data Monitoring Committee feedback and an internal review of unexpectedly high adverse-event rates. ([nature.com](https://www.nature.com/articles/s41467-025-60598-4))