A university spin off is developing a nose spray that could cure the common cold.

Ena Therapeutics, a Melbourne company set up in 2014, is testing a method that engages the body’s natural “killer” cells against respiratory viruses.

So far it has tested the drug dubbed INNA-X against seasonal and swine flu, a respiratory illness common in children under two called RSV, and rhinovirus which is the main cause of the common cold.

Ena CEO Christophe Demaison says they are in the process of testing the compounds against COVID-19.

All research so far has been in mice at the pre-clinical lab stage. About seven of every 1000 drug candidates in the lab make it to market.

Demaison says they plan to move to large animal toxicology studies this year, the step before looking at human trials.

So far $10m has been invested into Ena by university venture capital fund Uniseed and by the Brandon Capital managed Medical Research Commercialisation Fund (MRCF).


Turning the immune system on faster

The mechanism Ena is using has tickled scientists’ fancy for about 20 years, but the complex nature of human immunity has thwarted attempts to turn it into a respiratory drug.

The synthetic compounds mimic a bacterial component that is recognised by the toll-like receptor 2, or TLR2 for short.

TLR2 is one of the proteins that recognises foreign pathogens and then sends messages to the body’s immune system, which then releases its killer cells — neutrophils, eosinophils, macrophages and so forth — to do the dirty deeds necessary to rid the body of an infection.

The problem in the past has been that tricking the body into releasing TLR2s to fight off a respiratory infection has given some people flu-like symptoms and/or set off massive inflammation (hyper-inflammation has been a big problem for elderly COVID-19 patients).

Demaison says the specific profile of the compound that doesn’t set off that kind of hyper-inflammatory process.

The company is trying to prompt the body into fighting off an infection before it spreads, because the elderly, people with compromised immune systems and conditions like asthma are less adept at fighting off an initial infection and can develop secondary problems, such as pneumonia.

Research so far indicates that snorting the stuff stops infection of new cells at the inoculation site, inhibits the movement of the virus into lower airways, reduces the viral load and reduces virus-triggered inflammation.


More serious than the common cold

Sadly, the idea is not to deliver a common cold cure but a treatment for people at risk of developing secondary infections.

By squirting a spray up your nose (the location where respiratory infections usually start), Ena hopes to prevent it from heading south to the lungs.

The company says it can also protect against the flu for seven days after taking the compound, at least in mice. This is because the body’s killer cells are already on alert. These look for general foreign nasties rather than specific pathogens, as cells trained by a vaccine do.

The risk groups Ena is targeting are children, the elderly and patients with chronic respiratory diseases such as asthma and COPD.

For these people, getting a cold or the flu can lead to hospitalisation or death as underlying conditions are worsened and secondary infections hit harder, causing issues like severe acute respiratory syndrome, acute lung injury, and organ failure.

Ena says 20-30 per cent of the US population falls into the at-risk category.

“The CDC estimates that during the winter 2018-19 flu season, there has been 531,000 and 647,000 hospitalisations related to influenza in the US alone,” the company says.

The current standard of care for respiratory infections are not antivirals but symptomatic relief such as inhaled corticosteroids.