SARS-CoV-2, the new coronavirus that causes COVID-19, is transmitted primarily through airborne infectious droplets and tiny particles. For this reason, the respiratory tract, the entry point of the virus, could be a good target for drugs aimed at protecting us from the disease.
This is the rationale behind Eureka Therapeutics' development of Invisimask, a human monoclonal antibody. An anti-Covid nasal spray formulation that has also been explored by the University of San Francisco in recent months (AeroNabs) and from that of Pittsburgh (Q-Griffithsin) Now, the anti Covid nasal spray has reported promising results in mice.
Invisimask, spray and protect
A single administration of Eureka's drug into the nose protected the mice against SARS-CoV-2 for at least 10 hours, even at the lowest concentrations tested.
Company researchers described in a paper on the bioRxiv preprint site.
Eureka's team calculates that the Invisimask anti-Covid nasal spray could work as a daily preventative measure, and is preparing a clinical trial application with the FDA.
An invisible mask
“We envision a daily nasal spray that works like an invisible mask in slowing the spread of Covid,” explains Eureka's CEO in a statement. Cheng Liu, Ph.D.. “The use of antibodies in a preventative nasal spray adds to the arsenal of tools we have to fight the spread of the virus. The concept can also be applied to other airborne diseases. We are thrilled with the results and are working to advance the product for human use.”
Like the many other COVID-19 antibody products available, Eureka's targets the spike protein of SARS-CoV-2 to prevent the virus from entering and infecting healthy host cells. The Invisimask prototype showed a high capacity to bind to the spike protein and to efficiently inhibit various mutated forms, including the most widespread and infectious one today, D614G.
Invisimask, Eureka Therapeutics anti Covid nasal spray
The Eureka team further modified their drug to also increase its ability to bind to mucin, a protein produced by surface cells that produce mucus. The goal was to extend the retention time of the antibody in the respiratory tract, and it appears to have been achieved.
Eureka's team has indeed shown that the modified antibodies enhanced the neutralization of the virus.
InvisiMask currently remains stable in an anti Covid nasal spray formulation for up to two weeks at 37 degrees Celsius.
In mice, a single spray of the antibody at the lowest dose of 25 μg provided at least 10 hours of protection against virus infection at its highest tested viral load.
Nasal spray treatments under study
Eureka is one of the many companies that have focused their research on Covid treatment. However, the formula of the nasal spray is being studied, as mentioned, also by other companies.
In addition to those mentioned, Iowa State University is collaborating with Zeteo Biomedical to design a vaccine in nasal spray form. Twist Bioscience is considering turning its single-domain antibodies, or nanobodies, into a preventative daily nasal spray after also receiving promising results in mice.
Regeneron's Covid antibody cocktail has won FDA authorization for emergency use for outpatient treatment. The company is working to provide the cocktail in the form of an anti-Covid nasal spray.
Nasal sprays containing antibody therapy require a about 10.000 times lower dosage to that needed for systemic infusions, according to Eureka.
“This will significantly reduce the cost and make it accessible for wider use,” the researchers write in the study.
