Discovery and Synthesis of a Phosphoramidate Prodrug of a Pyrrolo[2,1‑f][triazin-4-amino] Adenine C‑Nucleoside (GS-5734) for the Treatment of Ebola and Emerging Viruses
datasetposted on 07.05.2020, 20:43 by Dustin Siegel, Hon C. Hui, Edward Doerffler, Michael O. Clarke, Kwon Chun, Lijun Zhang, Sean Neville, Ernest Carra, Willard Lew, Bruce Ross, Queenie Wang, Lydia Wolfe, Robert Jordan, Veronica Soloveva, John Knox, Jason Perry, Michel Perron, Kirsten M. Stray, Ona Barauskas, Joy Y. Feng, Yili Xu, Gary Lee, Arnold L. Rheingold, Adrian S. Ray, Roy Bannister, Robert Strickley, Swami Swaminathan, William A. Lee, Sina Bavari, Tomas Cihlar, Michael K. Lo, Travis K. Warren, Richard L. Mackman
The recent Ebola virus (EBOV) outbreak in West Africa was the largest recorded in history with over 28,000 cases, resulting in >11,000 deaths including >500 healthcare workers. A focused screening and lead optimization effort identified 4b (GS-5734) with anti-EBOV EC50 = 86 nM in macrophages as the clinical candidate. Structure activity relationships established that the 1′-CN group and C-linked nucleobase were critical for optimal anti-EBOV potency and selectivity against host polymerases. A robust diastereoselective synthesis provided sufficient quantities of 4b to enable preclinical efficacy in a non-human-primate EBOV challenge model. Once-daily 10 mg/kg iv treatment on days 3–14 postinfection had a significant effect on viremia and mortality, resulting in 100% survival of infected treated animals [Nature 2016, 531, 381−385]. A phase 2 study (PREVAIL IV) is currently enrolling and will evaluate the effect of 4b on viral shedding from sanctuary sites in EBOV survivors.