Abstract Marburg virus (MARV) VP40 protein (mVP40) directs egress and spread of MARV, in part, by recruiting specific host WW-domain containing proteins via its conserved PPxY Late (L) domain motif to facilitate efficient virus-cell separation. We reported previously that small molecule compounds targeting the viral PPxY/host WW-domain interaction inhibited VP40-mediated egress and spread. Here, we report on the antiviral potency of novel compound FC-10696, which emerged from extensive structure activity relationship (SAR) of a previously described series of PPxY inhibitors. We show that FC-10696 inhibits egress of both mVP40 VLPs and egress and spread of authentic MARV from HeLa cells and primary human macrophages. Moreover, FC-10696 treated mice displayed delayed onset of weight loss, clinical signs, and significantly lower viral loads compared to controls, with 14% of animals surviving 21 days following a lethal MARV challenge. Thus, FC-10696 represents a first-in-class, host-oriented inhibitor effectively targeting late stages of the MARV lifecycle.

Compound FC-10696 Inhibits Egress and Spread of Marburg Virus