A new study published in Science Advances reveals that an oral antiviral pill successfully protected monkeys from lethal Ebola virus infection, potentially revolutionizing treatment options for one of the world's deadliest diseases.
Researchers at The University of Texas Medical Branch at Galveston tested Obeldesivir (ODV), the oral form of the antiviral Remdesivir, on rhesus and cynomolgus macaques infected with the Makona variant of Ebola virus. The results showed remarkable efficacy, with 100% protection in rhesus macaques and 80% protection in cynomolgus macaques.
Breakthrough in Ebola Treatment
Lead researcher Thomas Geisbert, a virologist at The University of Texas Medical Branch at Galveston, emphasized the significance of these findings. The study involved infecting the primates with approximately 30,000 times the lethal dose for humans, making the survival rates particularly impressive despite the relatively small sample size.
"These findings suggest that ODV treatment affords the opportunity for the development of adaptive immunity while mitigating excessive inflammation, potentially preventing fatal outcomes," the researchers noted in their study.
In the experiment, 10 monkeys received a daily Obeldesivir pill after infection, while three control monkeys received no treatment and subsequently died. The treated monkeys showed significant resistance to the virus, with rhesus macaques—which are biologically closer to humans—showing complete protection.
Advantages Over Current Treatments
Obeldesivir offers several critical advantages over existing Ebola treatments. Current antibody-based therapies only work against specific strains like the Zaire strain and require costly cold storage facilities—infrastructure that is often lacking in sub-Saharan Africa where most outbreaks occur.
"Obeldesivir's broad-spectrum protection compared to other antibody treatments is a huge advantage," Geisbert explained. The oral administration route eliminates the need for specialized medical personnel to administer injections, making it potentially more accessible in remote or resource-limited settings.
The researchers specifically highlighted that they were "really trying to come up with something" more practical and easier to use that "could be used to help prevent, control, and contain outbreaks" in regions with limited healthcare infrastructure.
Mechanism and Future Applications
The antiviral was originally developed for COVID-19 but has shown broad activity across several RNA viruses, including the filovirus family to which Ebola belongs. Previous research had demonstrated its effectiveness when administered within 24 hours of exposure.
This latest study improved upon earlier research by using mucosal administration of the virus in macaques, which better mimics natural infection pathways and allows for more accurate assessment of the drug's effectiveness.
Based on these encouraging results, U.S. pharmaceutical company Gilead has already advanced Obeldesivir to Phase 2 clinical trials for the Marburg virus, a close relative of Ebola that also causes hemorrhagic fever with high mortality rates.
Ebola: A Persistent Threat
Ebola virus disease remains one of the most feared infectious diseases, with mortality rates approaching 90% in some outbreaks. First discovered in the Democratic Republic of Congo (DRC), the virus is believed to have a natural reservoir in fruit bats, which can transmit the disease to primates, including humans.
Six species of Ebola virus are known to cause disease in humans: Zaire, Sudan, Bundibugyo, Reston, Tai Forest, and Bombali. The Zaire strain has been responsible for the majority of outbreaks over the past decade, including the devastating 2014-2016 West African epidemic that claimed over 11,000 lives.
The development of an effective oral treatment could dramatically change the approach to managing Ebola outbreaks, potentially reducing mortality rates and limiting transmission in affected communities. If proven effective in human trials, Obeldesivir could become a critical tool in the global health response to Ebola and related viral hemorrhagic fevers.
