Discovery of Sisunatovir (RV521), an Inhibitor of Respiratory Syncytial Virus Fusion

RV521 is an orally bioavailable inhibitor of respiratory syncytial virus (RSV) fusion that was identified after a lead optimization process based upon hits originated from physical property directed hit profiling exercise at Reviral. This encompassed collaborations with number contract organizations collaborative medicinal chemistry and virology during the phase in addition to those utilized as compound proceeded through preclinical clinical evaluation. exhibited mean IC50 1.2 nM against panel RSV A B laboratory strains isolates antiviral efficacy Balb/C mouse model infection. Oral bioavailability species ranged 42 >100% evidence highly efficient penetration into lung tissue. In healthy adult human volunteers experimentally infected RSV, potent effect observed significant reduction viral load symptoms compared placebo.