A nasal spray that blocks the absorption of the SARS-CoV-2 virus completely protected ferrets it was tested on, according to a small study published Thursday by an international team of scientists. The study, which was limited to animals and has not yet been peer reviewed, has been evaluated by several health experts at the request of the New York Times.
If the spray, which scientists have described as non-toxic and stable, proves effective in humans, it could provide a new way to fight the pandemic. A daily spritz in the nose would act like a vaccine.
“Having something new that works against the coronavirus is exciting,” said Dr. Arturo Casadevall, president of immunology at the Johns Hopkins Bloomberg School of Public Health, who was not involved in the study. “I could imagine that this is part of the arsenal.”
Work has been underway for months by scientists at Columbia University Medical Center in New York, Erasmus Medical Center in the Netherlands, and Cornell University in Ithaca, New York.The study was funded by the National Institutes of Health and Columbia University Medical Center.
The team would need additional funding to continue clinical trials in humans. Dr Anne Moscona, a pediatrician and microbiologist at Columbia and co-author of the study, said they had applied for a patent on the product, and she hoped Columbia University would approach Operation Warp Speed. From the federal government or big pharmaceutical companies looking for new ways to fight the coronavirus.
The spray directly attacks the virus. It contains a lipopeptide, a particle of cholesterol linked to a chain of amino acids, the building blocks of proteins. This particular lipopeptide exactly matches a stretch of amino acids in the spike protein of the virus, which the pathogen uses to attach to a human airway or to a lung cell.
Before a virus can inject its RNA into a cell, the peak must actually decompress, exposing two chains of amino acids, in order to fuse with the cell wall. As the tip moves up to complete the process, the lipopeptide in the spray inserts itself, hooking onto one of the amino acid chains on the tip and preventing the virus from attaching itself.
“It’s like you close a zipper but put another one inside, so the two sides can’t meet,” said Matteo Porotto, a microbiologist at Columbia University and one of the authors of the article.
The work was described in an article published on the bioRxiv preprint server Thursday morning, and has been submitted to the journal Science for peer review.
Dr Peter J. Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine, said the therapy looked “really promising.”
“What I would like to know now is how easy it is to scale production,” he said.
In the study, the spray was administered to six ferrets, which were then divided into pairs and placed in three cages. Also in each cage were two ferrets who had been given a placebo spray and a ferret who had been deliberately infected with SARS-CoV-2 a day or two earlier.
Ferrets are used by scientists who study influenza, SARS, and other respiratory illnesses because they can pick up viruses through the nose just like humans do, although they also become infected through contact with feces. or by scratching and biting.
After 24 hours together, none of the treated ferrets contracted the disease; all of the ferrets in the placebo group did.
“Replication of the virus has been completely blocked,” the authors wrote.
The protective spray attaches to cells in the nose and lungs and lasts for about 24 hours, said Dr Moscona. “If it works well in humans, you could sleep in a bed with an infected person or be with your infected children and still be safe,” she said.
Amino acids come from a part of the spike protein in coronaviruses that rarely mutates. Scientists tested it against four different variants of the virus, including the well-known ‘Wuhan’ and ‘Italian’ strains, as well as the coronaviruses that cause SARS and MERS.
In cell cultures, it protected completely against all strains of the pandemic virus, fairly well against SARS and partially against MERS.
The lipoprotein can be inexpensively produced as a freeze-dried white powder that does not need refrigeration, said Dr Moscona. A doctor or pharmacist can mix the powder with sugar and water to make a nasal spray.
Other labs have designed antibodies and “mini-proteins” that also block the SARS-CoV-2 virus from entering cells, but these are chemically more complex and may need to be stored at cold temperatures.
Dr Moscona and Dr Porotto have been collaborating on similar “fusion inhibitor” peptides for 15 years, they said on a conference call. They developed it against measles, Nipah, parainfluenza and other viruses.
But these products have garnered little commercial interest, Dr Porotto said, because an effective measles vaccine already exists and because the deadly Nipah virus only occasionally appears in distant places like Bangladesh and Malaysia.
Monoclonal antibodies to the novel coronavirus have been shown to prevent infection and treat it, but they are expensive to make, require refrigeration, and must be injected. Australian scientists have tested a nasal spray against Covid-19 in ferrets, but it works by boosting the immune system, not directly targeting the virus.
Because lipopeptides can be shipped as a dry powder, they could be used even in rural areas of poor countries with no refrigeration, Dr Moscona said.
Dr Moscona, a pediatrician who usually works on parainfluenza and other viruses that infect children, said she was most interested in getting the product to poor countries that may never have access to monoclonal antibodies and vaccines. to mRNA that Americans may soon have. But she has little experience in this area, she says.