Additional Relevant Details BCX4430 is a broad spectrum antiviral that is being tested in a Phase 1 clinical safety and pharmacology study in healthy subjects. BCX4430 has demonstrated survival benefits in nonclinical studies against a variety of serious pathogens, including Ebola, Marburg, and Yellow Fever viruses. Since September 2013, NIAID has supported BioCryst in developing BCX4430 as a therapeutic for Ebola and Marburg viruses under Contract No. HHSN272201300017C.