A team of researchers at the University of Helsinki, Finland, report they have developed a molecule that can be administered nasally to prevent the development of COVID-19 symptoms by all known variants of the SARS-CoV-2 virus. The team noted that the molecule could be a tool used in future pandemics since its capabilities are aimed at preventing infection and spreading of the virus.
Reporting in the journal Nature Communications, the investigators reported that in laboratory animal studies, the molecule called TriSb92 targets a conserved region in the viral spike protein that is common to all current variants of the coronavirus to inhibit its function. The study noted that an intranasal administration of just five or 50 micrograms of TriSb92 as early as eight hours before exposure as well as four hours after protected mouse models from infection. The researchers noted that the molecule remains fully functional for up to 18 months when kept at room temperature.
“When administered nasally, the TriSb92 molecule is extremely effective in preventing infection, and experiments carried out in cell cultures indicate that it also encompasses the very latest variants, including XBB, BF7 and BQ.1.1,” said postdoctoral researcher Anna R. Mäkelä who works in Prof. Kalle Saksela’s research group.
Vaccines have been the primary method, thus far, of slowing the spread of the coronavirus, yet may provide limited protection against emerging variants. “The latest variants effectively avoid the immune protection provided by both vaccines and the COVID-19 disease, and current vaccines are not effective in preventing transmission,” Mäkelä says.
The nasal spray could also serve as a means to protect those who haven’t developed adequate immunity to the disease, as well as people who are immunocompromised, such as cancer patients.
The researchers said that the development of TriSb92 molecule could be used against future animal-borne relatives of the SARS-CoV-2—which are anticipated to be the culprits of any future coronavirus pandemics—since the region it targets is conserved.“Since the region in the coronavirus’ spike protein affected by the TriSb92 molecule has remained almost unchanged in all viral variants so far emerged, it can be assumed to be effective also against future SARS-CoV-2 variants,” Mäkelä said. “The easily and inexpensively produced TriSb92 could be a very important first line of defense in curbing such a new pandemic, pending the development, production and distribution of vaccines.”
In their report, the team noted that many labs looking to manufacture more economical SARS-CoV-2 reagents are moving from monoclonal antibodies to smaller antibody fragment, such as single variable domain-based nanobodies—some of which have shown efficacy in combating the virus in early studies in cell culture and animal models. To develop the TriSb92 molecule the Finnish researchers used sherpa-body technology, which is both inexpensive and could be applicable to the development of similar molecule to protect against other viral diseases such as influenza and respiratory viruses.
“The whole approach stems from a technical solution based on a binder protein platform developed in Finland, which was not originally intended for the development of an antiviral drug. It provides an opportunity for many other new initiatives based on the accurate identification of diseased cells or pathogens in patients,” Mäkelä noted.
The team will now move from testing the molecule against animal models to shepherding it through in-human clinical trials with an eye toward eventual commercialization.
