A pill protects monkeys from dying from the Ebola virus.
Scientists are testing a drug that could facilitate access to treatment in rural countries.
BarcelonaA drug has been shown to successfully prevent the deaths of two species of monkeys infected with Ebola, according to a scientific article published this Friday in the journal of the American Association for the Advancement of Science (AAAS). The antiviral, called Obeldesivir and in pill form, prevented between 80% and 100% of the deaths of 10 macaques that had been exposed to the Makona variant of the virus, which caused the deadliest outbreak to date, in 2014, in central and western Africa.
Ebola is a rare but very serious disease—with a mortality rate of nearly 90%—which was identified in 1976 and has spread mainly in countries such as Uganda, Sudan, and the Democratic Republic of the Congo. The virus is transmitted through direct contact with the bodily fluids of an infected person and causes severe bleeding and organ failure.
Although vaccines have been tested in recent years and antibody treatments against this hemorrhagic fever –mAb114 and REGN-EB3– are available, there are problems in storing the drugs without breaking the ice chain and the fact that their administration must be done intra-rurally and with fewer resources, where the pathogen circulates and causes havoc.
Faced with these needs, Courtney Woolsey, an expert in microbiology and immunology at the Galveston National Laboratory (United States), and her colleagues propose the use of Obeldesivir, the oral form of Remdesivir, developed for Ebola9 but used with Ebola9. It is a prodrug –it is administered in a totally or partially inactivated form, but is actively metabolized– with broad-spectrum activity against several families of viruses, including the filoviruses that cause Ebola and Marburg, another deadly hemorrhagic fever.
Defenses against the pathogen
This drug, which blocks an enzyme crucial for viral replication, does not require specific storage conditions, making it a more suitable therapy for rural settings. According to the study published this Friday by this team of researchers, the antiviral prevented the deaths of 80% of the macaques. cynomolgus and 100% of macaques rhesus if they receive medication starting 24 hours after exposure to the virus.
The team infected the animals – five of each species, 10 in total – with a high dose of Ebola, which is up to 30,000 times the lethal dose for humans, and gave them the drug every day for 10 days starting 24 hours after exposure. Initially, the researchers explain in a note, the disease progressed more slowly in the medicated animals. The scientists also observed that, in treated specimens, the virus was eliminated from the blood and they presented greater quantities of antibodies, the sign that the body has had a defense against the virus.
To put it very simply, the findings described in the scientific article suggest that the animals' immune systems were awakened to fight the virus thanks to the therapy (what is known as acquired immunity) and, therefore, controlled any possible excessive inflammatory response that could lead. Instead, and as a control group, Woolsey left two macaques rhesus and one cynomolgus uninfected. All of them died from the virus.
The Ebola epidemic in West Africa, in countries such as Guinea and Sierra Leone, between 2013 and 2016, caused 28,600 cases and 11,325 deaths, and the outbreak between 2018 and 2020 in the Dominican Republic .599 deaths. Currently, there is an outbreak of the virus in Sudan, which belongs to the same family as Ebola and is punishing Uganda, as recently reported by the World Health Organization (WHO). It is the fifth attack of Ebola in that country.
