Persistent infections are tough to tackle with traditional antibiotics because bacteria can enter a state of slowed metabolism and form difficult to penetrate biofilms. Spero Therapeutics LLC hopes to neutralize these bacteria and increase their sensitivity to bactericidal compounds by inhibiting MvfR, a central regulator of virulence and biofilm formation.

Biofilms formed during chronic infections by pathogens such as Pseudomonas aeruginosa are notoriously difficult to clear with traditional antibiotics in part because the bacteria can enter into a semi-quiescent state where they up-regulate drug-transporters and slow their growth, rendering them less sensitive to antibiotics that depend on replication and protein synthesis.