CompletedPhase IIInterventional

A Phase II study to understand the safety and effects of inhaled SNG001, the study medication, in patients who are mechanically ventilated due to a respiratory viral infection in the lungs

Severe viral chest infections, such as flu or COVID-19, can make people extremely unwell and require help from a breathing machine (ventilator) in an intensive care unit (ICU). This trial is testing an inhaled medicine called SNG001 to see if it can help these critically ill patients recover. SNG001 contains interferon beta, a protein the human body naturally produces to fight off viral infections. In this study, the medicine is delivered directly into the lungs through the breathing tube using a special mister (nebuliser). The trial has two parts. The first part checks that the medicine is safe at different doses. The second part compares SNG001 to a dummy treatment (placebo) in up to 450 patients to see if it speeds up recovery. All patients continue to receive their standard hospital care throughout the trial.

At a glance

Status

Completed

Phase

Phase II

Sponsor

Synairgen (United Kingdom)

Enrolment target

450

Start

04 Dec 2025

Estimated completion

02 Feb 2026

Respiratory viral infections

What is this study about?

When viruses like flu, RSV, or COVID-19 cause severe lung infections, patients can become critically ill with viral pneumonia. In the most severe cases, patients are admitted to an intensive care unit (ICU) and connected to a mechanical ventilator, which is a machine that helps them breathe. While ventilators keep patients alive, doctors need better treatments that actively fight the virus directly in the lungs to speed up recovery.

This study tests a medicine called SNG001. SNG001 is a mist containing interferon beta-1a, a man-made version of a natural protein your body produces to defend itself against viral attacks. By delivering this protein straight into the lungs through the ventilator's breathing tubes, researchers hope to boost the lungs' natural defences right where the infection is located.

The trial takes place in two stages. The first stage tests the safety of SNG001 in a small group of patients to find the best dose. Once safety is confirmed, the second stage will test how well the medicine works compared to an inactive liquid (a placebo) in a larger group of patients. An independent safety board monitors the study at all times.

Finding a treatment that helps clear lung viruses faster could help patients come off breathing machines sooner, reduce the time they spend in intensive care, and improve their long-term recovery. The knowledge gained from this trial could help shape how severe viral chest infections are treated in the NHS and across the world.

Key takeaways

Tests an inhaled, natural virus-fighting protein (SNG001) for severe viral lung infections.
Aimed at patients in intensive care who are currently on a mechanical breathing machine.
Treatment is given daily through the breathing tube for up to 14 days.
Patients continue to receive all their normal intensive care medications and support.
Participation is entirely voluntary and overseen by an independent safety committee.

Who may be eligible?

This trial is specifically for adults who are admitted to an intensive care unit and need a mechanical breathing machine because of a confirmed lung virus. Eligible viruses include the flu, COVID-19, RSV, common cold viruses (rhinovirus), and other respiratory viruses confirmed by a hospital swab test.

Timing is very important for this study. The patient must receive their first dose of the study medicine within 48 hours of having their breathing tube put in. In the first part of the study, patients in the UK must be between 35 and 50 years old. In the second part, participants can be 18 to 49 years old with an existing condition that weakens their immune system, or 50 years and older with or without immune problems.

Because patients on breathing machines are usually asleep under sedation, consent is often provided by a family member or legal representative in line with UK law, until the patient is well enough to make decisions for themselves. Women under 55 must also have a negative pregnancy test to take part.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Currently admitted to an intensive care unit (ICU)
Connected to a mechanical breathing machine (ventilated) within the last 48 hours
Confirmed positive test for a respiratory virus (such as flu, COVID-19, or RSV)
Aged 18 or older (specific age criteria apply depending on health history and study stage)
Negative pregnancy test for women under 55 years of age

Answer every question to see your result.

What does participation involve?

Because participants are already in intensive care, taking part does not require any extra clinic visits. Patients are given the study medicine or a dummy treatment once a day through their breathing machine using a nebuliser, which turns the liquid medicine into a fine mist. Treatment lasts for up to 14 days, or until the patient is well enough to leave hospital, whichever comes first. Doctors and nurses will run routine ICU checks, take blood and breathing samples to measure virus levels, and carefully track recovery. Taking part will not interrupt any of the patient's normal intensive care medicines or standard treatments.

Potential risks and benefits

The possible benefit of taking part is that SNG001 might help clear the chest virus faster, ease symptoms, and reduce the time spent on a breathing machine, though this cannot be guaranteed. SNG001 has been tested in over 750 patients with conditions like asthma and COVID-19 and was generally well tolerated with no major safety issues. However, because it has not been given to patients on mechanical ventilators before, there is a risk of unexpected side effects. To protect patients, the study starts with lower doses and an independent committee reviews all safety data regularly. Taking part is completely voluntary, and family members or patients can withdraw from the study at any time without affecting their standard NHS care.

Locations (16)

Aberdeen Royal Infirmary
Approximate
Aberdeen, Scotland
University Hospitals Birmingham NHS Foundation Trust
City only
Birmingham, England
Bradford Teaching Hospitals NHS Foundation Trust
City only
Bradford, England
Royal Sussex County Hospital
Approximate
Brighton, England
Cardiff and Vale U H B
City only
Cardiff, Wales
Glasgow Royal Infirmary
Unverified
Glasgow, Scotland
Hull University Teaching Hospitals NHS Trust
Unverified
Hull, England
Leicester Royal Infirmary
Unverified
Leicester, England
University College London Hospitals NHS Foundation Trust
Unverified
London, England
Royal Free London NHS Foundation Trust
Unverified
London, England
St George's Healthcare Nhst
Unverified
London, England
The James Cook University Hospital
Unverified
Middlesbrough, England

Common questions

What is SNG001?

SNG001 is an inhaled medicine containing interferon beta, a natural protein that helps the body's immune system recognise and fight off viral infections in the lungs.

How is the medicine given to someone on a breathing machine?

It is turned into a fine mist using a device called a nebuliser, which attaches directly to the breathing tube so the medicine flows straight into the lungs.

Will normal hospital treatment stop if a patient joins the study?

No. Patients will continue to receive all standard NHS intensive care treatments, oxygen, antibiotics, and antiviral medicines alongside the study treatment.

What happens if the patient cannot give consent?

Because patients on ventilators are heavily sedated, a family member or legal representative can give permission on their behalf, following strict UK clinical trial rules.

What is a placebo?

In Part 2 of the study, some patients will receive a placebo, which looks identical to the real medicine but contains no active ingredients. This helps scientists prove whether SNG001 really works.

How to find out more

Sophie Hemmings

submissions@synairgen.com +44 (0)23 80512 800 Official trial record

Always speak to your GP or specialist before deciding to take part in a study.