Discovery of Sisunatovir (RV521), an Inhibitor of Respiratory Syncytial Virus Fusion.
Cockerill GS, Angell RM, Bedernjak A, Chuckowree I, Fraser I, Gascon-Simorte J, Gilman MSA, Good JAD, Harland R, Johnson SM, Ludes-Meyers JH, Littler E, Lumley J, Lunn G, Mathews N, McLellan JS, Paradowski M, Peeples ME, Scott C, Tait D, Taylor G, Thom M, Thomas E, Villalonga Barber C, Ward SE, Watterson D, Williams G, Young P, Powell K.
RV521 is an orally bioavailable inhibitor of respiratory syncytial virus (RSV) fusion that was identified after a lead optimization process based upon hits that originated from a physical property directed hit profiling exercise at Reviral. This exercise encompassed collaborations with a number of contract organizations with collaborative medicinal chemistry and virology during the optimization phase in addition to those utilized as the compound proceeded through preclinical and clinical evaluation. RV521 exhibited a mean IC<sub>50</sub> of 1.2 nM against a panel of RSV A and B laboratory strains and clinical isolates with antiviral efficacy in the Balb/C mouse model of RSV infection. Oral bioavailability in preclinical species ranged from 42 to >100% with evidence of highly efficient penetration into lung tissue. In healthy adult human volunteers experimentally infected with RSV, a potent antiviral effect was observed with a significant reduction in viral load and symptoms compared to placebo.