What Synairgen does

Synairgen plc is a UK-based clinical-stage respiratory biotechnology company whose sole asset is SNG001, an investigational inhaled formulation of interferon beta (IFN-β) being developed as a host-directed, broad-spectrum antiviral delivered directly into the lungs for severe viral lung infections. The technology is designed to restore IFN-β levels suppressed by viral pathogens and applies across multiple viruses including SARS-CoV-2, influenza, RSV, adenovirus, parainfluenza and rhinovirus, with delivery via a custom vibrating mesh nebuliser developed in partnership with Aerogen for use in mechanically-ventilated ICU patients. SNG001 has been evaluated across multiple Phase 1-3 programmes spanning asthma (SG004, SG005), COPD (SG015), hospitalised COVID-19 (SG016 Phase 2 in The Lancet Respiratory Medicine, SG018 SPRINTER Phase 3 in 17 countries), the NIH/NIAID-sponsored ACTIV-2 platform trial, the observational UNIVERSAL study with the University of Southampton and Janssen, and most recently the global Phase 2 INVENT study targeting 550 mechanically-ventilated patients with 28-day all-cause mortality as the primary endpoint.

The business model has historically been pre-revenue biotech development: funding has come from equity (notably a £18 million subscription from majority shareholder TFG Asset Management in January 2025) rather than product sales, and the intended future commercialisation pathway was a drug-device combination product (SNG001 + Aerogen nebuliser) sold to hospital systems, ICU networks and hospital pharmacies on a per-treatment pricing basis. Following the February 2026 termination of the INVENT trial due to under-recruitment and withdrawal of further financing from Tetragon Partners on behalf of TFG-managed funds, Synairgen is winding down operations and pursuing a Members Voluntary Liquidation in H2 2026, while conducting outreach to over 100 pharmaceutical and biotech companies to identify any potential acquirer for SNG001 intellectual property. The company has completed an all-staff redundancy, is closing its Southampton laboratory facility and US/EU subsidiaries, and was re-registered as a private limited company after AIM cancellation in April 2025.

Name

Synairgen

Legal name

Synairgen plc (UK operating entity); Synairgen Research Ltd (research subsidiary)

Website

https://synairgen.com

Company type

Private

Founded year

2003

Operating status

Closed

Headcount range

51–100 employees

Short description

Synairgen is a UK clinical-stage respiratory biotech developing SNG001, an inhaled interferon beta broad-spectrum antiviral for severe viral lung infections, delivered to mechanically-ventilated ICU patients via a custom Aerogen nebuliser. The company is winding down and pursuing Members Voluntary Liquidation in H2 2026.

Ownership category

akta.pro rank

Product category

Inhaled Antiviral Biologics

NAICS

Research and Development in Biotechnology (except Nanobiotechnology) (541714)

SIC

Pharmaceutical Preparations (2834)

akta.pro primary industry

mRNA Therapeutics (vaccines, protein replacement, immuno-oncology) (HLAAADAA)

akta.pro secondary industries

RNA Therapeutics Regulatory, Quality & Pharmacovigilance (GxP, comparability, post-market) (HLAAADAJ), RNA Therapeutics Clinical Development (trial design, endpoints, patient stratification) (HLAAADAH), RNA Therapeutics Safety & Immunogenicity (innate immune activation, tox, off-target) (HLAAADAI)

Keywords

• Respiratory biotechnology
• Inhaled antivirals
• Interferon beta therapy
• Drug-device combination
• Clinical-stage biopharmaceutical

Headquarters

HQ city

Southampton

HQ country

United Kingdom

HQ region

Europe

Offices6 records

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Personnel, Technology or R&D, Operations, Others

Revenue model

1. No active revenue streams (winding down): Clinical-stage biotech with no approved or commercial products; company is winding down operations and pursuing Members Voluntary Liquidation in H2 2026. SNG001 has never been approved or available commercially. Intended future commercialisation via out-licensing or sale of SNG001 asset.
2. Asset divestiture / IP licensing (exploratory): Company plans to explore whether there is any opportunity to divest certain intellectual property assets related to SNG001, with outreach to over 100 pharmaceutical and biotech companies to identify potential acquirers for the sole asset.

Pricing tiers

Go-to-market motion3 records

Distribution channels2 records

Marketing channels9 records

Core offering

Synairgen is a clinical-stage respiratory biotechnology company developing SNG001, an investigational inhaled formulation of interferon beta (IFN-β) delivered directly to the lungs as a host-directed broad-spectrum antiviral for severe viral lung infections. The company's programmes span asthma, COPD, COVID-19 and mechanically-ventilated ICU patients, with delivery via a custom nebuliser co-developed with Aerogen Ltd. Following termination of the Phase 2 INVENT trial in February 2026, Synairgen is winding down operations and seeking asset acquirers for SNG001.

Product overview

Synairgen plc is a UK-based clinical-stage respiratory biotechnology company whose sole clinical-stage asset is SNG001, an investigational inhaled formulation of interferon beta (IFN-β) being developed as a host-directed, broad-spectrum antiviral delivered directly into the lungs for severe viral lung infections. SNG001 has been evaluated across a portfolio of named clinical programmes spanning multiple patient populations: SG004 (Phase 1 in moderate asthma) and SG005 (Phase 2 in moderate-to-severe asthma), SG015 (Phase 2 in COPD), SG016 (Phase 2 in hospitalised COVID-19), SG018 SPRINTER (Phase 3 in hospitalised COVID-19 across 17 countries), the NIH/NIAID-sponsored ACTIV-2 trial, the observational UNIVERSAL study in collaboration with the University of Southampton and Janssen, and most recently the global Phase 2 INVENT study in mechanically-ventilated ICU patients, which dosed its first patient on 8 December 2025 before being terminated in February 2026 due to insufficient enrolment. Following the INVENT termination and the withdrawal of further financing from Tetragon Partners/TFG Asset Management UK LLP, Synairgen is winding down operations and pursuing a Members Voluntary Liquidation in H2 2026, while conducting outreach to potential acquirers for SNG001, which is delivered using a custom aerosol device developed in partnership with Aerogen Ltd.

Differentiator

Problem solved

Functional benefit

Brands

• SNG001: Investigational inhaled formulation of interferon beta (IFN-β) developed by Synairgen as a broad-spectrum antiviral for severe viral lung infections.
• Host Directed

Products and services

• SNG001 (inhaled interferon beta) Investigational inhaled formulation of interferon beta (IFN-β), a naturally occurring broad-spectrum antiviral protein, designed to restore IFN-β levels in the lungs and boost antiviral responses in patients with severe viral lung infections (RSV, rhinovirus, influenza, SARS-CoV-2, MERS-CoV, etc.). Delivered via a nebuliser, including on invasive mechanical ventilation, through a custom device developed with Aerogen Ltd. Granted FDA Fast Track status; not approved anywhere in the world and is the sole asset of Synairgen.

Quantifiable outcome

• Approximately 2 million people hospitalised in the US annually due to severe respiratory viral infections (HCUP).
• +4 more outcomes

Named customers1 record

Segments5 records

Ideal customer profiles2 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Integration1 record

Feature6 records

Partnerships

Eight partnerships are on record, tiered flagship / core, important, core, strategic (us government-sponsored) and standard adviser.

• Aerogen Ltd.flagship / coreStrategic or Co-development Partner · 12 November 2025Strategic partnership announced 12 November 2025 to develop and deliver a custom aerosol device for SNG001 (inhaled interferon-beta). Builds on a long-standing relationship and unites Aerogen's vibrating mesh nebuliser platform and manufacturing expertise with Synairgen's drug development programme. Manufacturing, supply and exclusivity terms are in place for future commercialisation. Aerogen's Solo nebuliser is the gold standard for respiratory patient care in over 80 countries, treating over 30 million patients worldwide.
• Asset MatchimportantChannel Partner/ Reseller/ Distributor · 8 May 2025Asset Match, an FCA-authorised firm (FRN 579310), operates an electronic off-market dealing facility for Synairgen ordinary shares following the company's cancellation from AIM trading in April 2025. Shares were admitted to trading on Asset Match on 8 May 2025 ahead of the first auction. Facility to remain in place for a minimum of two years from AIM cancellation (until 9 April 2027). Periodic auctions enable existing shareholders and new investors to trade shares.
• University of Southampton (Clinical Trials Unit)coreImplementation/ SI/ Consulting Partner · 5 September 2022Long-standing research and academic collaboration. Synairgen was founded as a 2003 spin-out from the University of Southampton by three of its professors. Co-leads the UNIVERSAL observational trial. Prof Tom Wilkinson is a key opinion leader and Prof Ratko Djukanovic is a co-founder and Professor of Medicine.
• U.S. National Institute of Allergy and Infectious Diseases (NIAID) / NIH ACTIV-2 Programmestrategic (us government-sponsored)Strategic or Co-development Partner · 1 October 2021SNG001 was investigated independently as part of the US National Institute of Health's ACTIV programme to accelerate the development of the most promising COVID-19 treatments. The ACTIV-2 study (ClinicalTrials.gov Identifier: NCT04518410) was sponsored by NIAID. An Independent Data Safety Monitoring Board recommended advancement from Phase 2 to Phase 3 in October 2021, but NIAID halted all patient recruitment in March 2022.
• BDO LLPstandard adviserImplementation/ SI/ Consulting PartnerAuditors of Synairgen. Based at Level 12, Thames Tower, Station Road, Reading, RG1 1LX, UK. Reports to the Audit Committee chaired by independent Non-Executive Director John Bradshaw.
• MUFG Corporate Marketsstandard adviserImplementation/ SI/ Consulting PartnerRegistrars for Synairgen, based at Central Square, 29 Wellington Street, Leeds, LS1 4DL. Issue share certificates on behalf of SNG to registered legal shareholders following AIM cancellation.
• Fieldfisherstandard adviserImplementation/ SI/ Consulting PartnerSolicitors for Synairgen, based at Riverbank House, 2 Swan Lane, London, EC4R 3TT.
• ICR Healthcarestandard adviserGTM or Marketing PartnerFinancial PR and Investor Relations adviser, based at 85 Gresham Street, London, EC2V 7NQ. Handles media and investor relations for Synairgen including distribution of corporate updates and clinical trial announcements.

Scale indicators13 records

Recent moves7 records

Expansion highlights3 records

Direct peers

• Ansun Biopharma: Clinical-stage developer of DAS181, an inhaled antiviral for severe respiratory infections including parainfluenza and influenza. Direct competitor to Synairgen's inhaled host-directed antiviral approach in the hospitalised/immunocompromised respiratory niche.
• Pulmatrix: Clinical-stage biotech developing inhaled therapeutics for respiratory diseases using its iSPERSE/iCALM delivery platforms. Highly comparable as a small inhaled-respiratory biotech targeting severe pulmonary indications.
• Soligenix: Late-stage biopharmaceutical company developing RiVax (ricin toxin) and other infectious disease/vaccine assets. Comparable small clinical-stage biotech operating in the antiviral/anti-infective space with similar capital constraints.

Broad incumbents

• Shionogi: Japanese pharma with approved antivirals (baloxavir for influenza, Xocova/ensitrelvir for COVID-19). Competes with SNG001 in the respiratory antiviral space via direct-acting mechanisms with much larger commercial infrastructure.
• Alnylam Pharmaceuticals: Leading RNAi therapeutics company with programmes in infectious disease (incl. respiratory targets). Larger incumbent with broader modality portfolio and stronger balance sheet but overlapping antiviral development programmes.
• Pfizer: Develops and commercialises Paxlovid (nirmatrelvir/ritonavir) for COVID-19 and other respiratory antivirals. The most likely strategic acquirer profile for SNG001 given its hospital antiviral portfolio and ICU commercial reach.
• Translate Bio (Sanofi): Sanofi-owned mRNA therapeutics platform that was developing vaccines for respiratory viruses including influenza. Represents the broader incumbent respiratory antiviral space and a potential acquirer/category competitor for SNG001.

Emerging players

• Arcturus Therapeutics: Develops mRNA-based vaccines and therapeutics for infectious disease including respiratory viruses (e.g., Kostaive for COVID-19). Comparable clinical-stage respiratory biotech targeting viral lung infections through a different modality.
• Vaxart: Clinical-stage developer of oral vaccines for respiratory viruses including RSV and influenza. Comparable small-cap respiratory infectious disease biotech with similar wind-down/trial-recruitment sensitivities.
• Aiolos Bio: Clinical-stage respiratory biotech (acquired by GSK in 2024) developing inhaled therapeutics for severe asthma and COPD exacerbations. Closely comparable single-asset inhaled respiratory biotech whose acquisition illustrates the exit path Synairgen is pursuing.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat4 records

Key risks6 records

Key highlights6 records

Customer concentration

• Xx.com/Synairgenplc
• LinkedInlinkedin.com/company/synairgen-research-ltd

Compliance2 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles10 records

Subsidiaries3 records

Funding overview

Funding rounds1 record

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Synairgen