Researchers have developed a nasal spray to protect vulnerable people from not only COVID-19 but also from infection with several other viruses. The treatment is being tested in Phase 3 trials in the United Kingdom.
People who receive immunosuppressive treatment after transplantation, have blood cancer or are on dialysis have more than 10% risk of dying from COVID-19.
Unfortunately, these people do not benefit much from COVID-19 vaccination, which generally does not protect them very well. This also applies to the approved antibody treatments, and the COVID-19 drugs from Merck, Pfizer and others have not been approved for long-term use.
Treatments thus still urgently need to be developed for these people: more than 4 million in Europe alone.
However, good news may be on the way. Researchers have developed a new treatment formulation that is being tested in a Phase 3 trial by the University of Cambridge in the United Kingdom.
“People with a compromised immune system have not experienced the benefits of vaccination. Their risk of severe COVID-19 is still very high. Treatments therefore need to be developed that benefit these people, and we have addressed this with a nasal spray that looks very promising so far,” explains a researcher who developed the treatment, Morten Otto Alexander Sommer, a founder of UNION Therapeutics and a Professor at the Technical University of Denmark, Kongens Lyngby.
Virus penetrates through the nose
When SARS-CoV-2 infects a person, it usually starts in the upper respiratory tract, with the virus penetrating the cell membrane of the cells in the nose, and then it begins to replicate.
When the virus has replicated sufficiently, the cells rupture and the virus spreads from the cells in the upper respiratory tract to the cells into the lower respiratory tract. From there, SARS-CoV-2 spreads to the rest of the body.
When the virus infects a cell, it induces a section of the membrane of a human cell to form an endosome that encapsulates the virus as it enters the cell.
The virus then escapes the endosome so that it can circulate freely around the cytosol inside the cell and take over all the cell’s molecular machinery and get the cell to produce viruses instead of maintaining cell function.
Encapsulating the virus and killing it
The new formulation for delivering niclosamide that Morten Otto Alexander Sommer has helped to develop is designed to prevent virus particles from breaking down the endosome so that a virus cannot penetrate and take over the cell.
Instead, the virus is isolated in the endosome and is eventually degraded.
Specifically, niclosamide alters the acidity balance of the endosome. Viruses need acidity, and niclosamide makes the endosome neutral.
The researchers have developed niclosamide as a nasal spray, so it is delivered right where the virus tries to penetrate the cells without affecting the rest of the body and causing possible-side effects.
“This is a completely different way of tackling viruses that does not depend on having to recognise various surface proteins on viruses. The treatment will likely work against other SARS-CoV-2 variants, both those we know today and probably also those that will come in the future,” says Morten Otto Alexander Sommer.
Phase 3 trials
The researchers have tested their treatment in cell experiments, in animal experiments, in a model of the respiratory tract and in the first clinical trials in humans, and the treatment was well tolerated.
The long series of promising results has led to a Phase 3 trial in the United Kingdom, where it has also been given Urgent Public Health Level 1 priority status by the health authorities, which helps the process by ensuring that the researchers have access to all the people on dialysis they need.
The participants will use the nasal spray over 9 months, and the researchers will then examine whether treatment with niclosamide results in fewer serious cases and deaths than treatment with a placebo.
This also means that the results of the trial are expected to be ready during 2022, and if the results are as successful as the initial trials, this may pave the way for approval by various health authorities so that the treatment can come on the market.
Also effective against influenza
The niclosamide nasal spray actually has potential beyond preventing COVID-19, since individuals with compromised immune systems also have high risk of contracting influenza or other airborne viral diseases.
Researchers from UNION Therapeutics have already demonstrated that the treatment is also effective against influenza.
“In general, treatments are lacking that can protect people with compromised immune systems against viral infections. Niclosamide looks very promising and may be a game-changer for millions of people who may soon no longer have to live in fear of COVID-19 or seasonal respiratory infections,” concludes Morten Otto Alexander Sommer.