Marburg virus (MARV) is a haemorrhagic fever virus belonging to the Filoviridae family that is highly lethal in humans. Historically, MARV has caused outbreaks in Central Africa. A recent outbreak in Rwanda resulted in 15 deaths. Unlike the closely related Ebola virus, there are no approved vaccines or treatments for MARV infection, though several candidates with pre-clinical efficacy have been reported.

In a recent study, Cross, Woolsey, Prasad et al. show that obeldesivir (ODV) — an oral nucleoside analogue prodrug with reported post-exposure prophylaxis effects against Sudan virus in nonhuman primates — has potent in vitro antiviral activity against several filoviruses, including Ebola virus, Sudan virus and MARV. In cynomolgus macaques, ODV administered orally once per day for 10 days, 24 hours post-infection, provided 80% protection against MARV infection with an accompanying reduction in plasma viral loads. Surviving macaques exhibited an enhanced activation of B cells, development of neutralizing antibodies, antigen presentation and immunoregulation.