Maftivimab monotherapy is effective in a non-human primate model of Bundibugyo virus disease
- 1Regeneron Pharmaceuticals, Inc.
Abstract
The 2026 outbreak of Bundibugyo ebolavirus (BDBV) in the Democratic Republic of the Congo and Uganda has created an urgent need for treatments for BDBV disease, yet the only FDA-approved ebolavirus therapeutics, the monoclonal antibody (mAb) cocktail Inmazeb and the mAb Ebanga, are indicated for Zaire ebolavirus (EBOV). Maftivimab (REGN3479), the most potent neutralizing component of Inmazeb, targets ebolavirus species GPs broadly; however, how it engages BDBV GP, whether it neutralizes BDBV-2026, and whether it protects against BDBV disease in vivo are unknown. Here we show that Maftivimab binds to BDBV-2007 GP with high affinity and potently neutralizes pseudoviruses carrying GP from a 2007 reference strain and the 2026 outbreak lineage. Additionally, a cryo-electron microscopy structure of Maftivimab Fab bound to trimeric BDBV-2007 GP superimposes closely on the EBOV GP:Maftivimab complex; importantly, all GP contact residues are conserved between the 2007 and 2026 BDBV sequences. Finally, in cynomolgus macaques challenged with BDBV-2007, a single dose of Maftivimab monotherapy given 7 days after infection, after the onset of clinical disease, rescued 6 of 6 animals, whereas 5 of 6 placebo-treated animals succumbed. These findings demonstrate that Maftivimab neutralizes BDBV, binds to its epitope on BDBV GP and is efficacious in treating established BDBV disease in the macaque model. The data support its evaluation in clinical trials during the ongoing or future outbreak.
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BibTeX
@misc{dittmann2026maftivimab,
title = {{Maftivimab monotherapy is effective in a non-human primate model of Bundibugyo virus disease}},
author = {M. Dittmann and D. M. Johnson and M. Rapp and A. Coppi and F. Isa and D. Ajithdoss and B. O. Fulton and R. Basu and A. K. Kania and K. E. Pascal and R. LeDesma and G. Ehrlich and A. Rafique and V. Marzec and J. Yuan and R. Liu and K. Alfson and T. Moir-Savitz and S. Gray and G. Ippolito and C. Hallam and J. Patterson and A. Baum and V. Mas Casullo and R. Copin and V. Kulkarni and M. C. Franklin and C. A. Kyratsous and J. M. Orengo},
howpublished = {bioRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.13.758840},
url = {https://www.biorxiv.org/content/10.64898/2026.10.13.758840v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Maftivimab monotherapy is effective in a non-human primate model of Bundibugyo virus disease
AU - M. Dittmann
AU - D. M. Johnson
AU - M. Rapp
AU - A. Coppi
AU - F. Isa
AU - D. Ajithdoss
AU - B. O. Fulton
AU - R. Basu
AU - A. K. Kania
AU - K. E. Pascal
AU - R. LeDesma
AU - G. Ehrlich
AU - A. Rafique
AU - V. Marzec
AU - J. Yuan
AU - R. Liu
AU - K. Alfson
AU - T. Moir-Savitz
AU - S. Gray
AU - G. Ippolito
AU - C. Hallam
AU - J. Patterson
AU - A. Baum
AU - V. Mas Casullo
AU - R. Copin
AU - V. Kulkarni
AU - M. C. Franklin
AU - C. A. Kyratsous
AU - J. M. Orengo
PY - 2026
DA - 2026/10/13
PB - bioRxiv
DO - 10.64898/2026.10.13.758840
UR - https://www.biorxiv.org/content/10.64898/2026.10.13.758840v1
AB - The 2026 outbreak of Bundibugyo ebolavirus (BDBV) in the Democratic Republic of the Congo and Uganda has created an urgent need for treatments for BDBV disease, yet the only FDA-approved ebolavirus therapeutics, the monoclonal antibody (mAb) cocktail Inmazeb and the mAb Ebanga, are indicated for Zaire ebolavirus (EBOV). Maftivimab (REGN3479), the most potent neutralizing component of Inmazeb, targets ebolavirus species GPs broadly; however, how it engages BDBV GP, whether it neutralizes BDBV-2026, and whether it protects against BDBV disease in vivo are unknown. Here we show that Maftivimab binds to BDBV-2007 GP with high affinity and potently neutralizes pseudoviruses carrying GP from a 2007 reference strain and the 2026 outbreak lineage. Additionally, a cryo-electron microscopy structure of Maftivimab Fab bound to trimeric BDBV-2007 GP superimposes closely on the EBOV GP:Maftivimab complex; importantly, all GP contact residues are conserved between the 2007 and 2026 BDBV sequences. Finally, in cynomolgus macaques challenged with BDBV-2007, a single dose of Maftivimab monotherapy given 7 days after infection, after the onset of clinical disease, rescued 6 of 6 animals, whereas 5 of 6 placebo-treated animals succumbed. These findings demonstrate that Maftivimab neutralizes BDBV, binds to its epitope on BDBV GP and is efficacious in treating established BDBV disease in the macaque model. The data support its evaluation in clinical trials during the ongoing or future outbreak.
SN - 2692-8205
ER -