hVIVO plc

("hVIVO", the "Company" or the "Group")

Consultancy contract signed with Decoy Therapeutics to support development of respiratory antiviral candidates

Consultancy engagement supports clinical development planning for antiviral programmes, with potential to advance to Phase I and human proof-of-concept studies

London, UK - 1 June 2026, hVIVO plc (AIM: HVO), a purpose-built, full-service international clinical development partner and the world leader in human challenge trials, announces it has signed a consultancy contract with Decoy Therapeutics ("Decoy") to support the development of its respiratory antiviral candidates.

Decoy is developing a portfolio of Designable Multi-Antiviral (D-MAV) candidates, a new antiviral category designed to address multiple viruses by targeting shared viral mechanisms across multiple respiratory viruses using a single adaptable therapeutic approach.

Under the agreement, hVIVO will provide consultancy services spanning translational modelling, regulatory strategy, scientific advice preparation, Chemistry Manufacturing and Controls (CMC) consulting, non-clinical development support and preparation of key clinical and regulatory documentation required for European and UK clinical trial submissions. The engagement also includes support for interactions with the European Medicines Agency (EMA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).

The consultancy programme is intended to support Decoy's clinical development strategy, including first-in-human dose selection, translational pharmacology planning and readiness for future clinical studies.

Subject to securing future financing and successful programme progression, Decoy also intends to conduct early proof-of-concept and likely follow-on studies with hVIVO, given its track record in human challenge trials.

Yamin 'Mo' Khan, Chief Executive Officer of hVIVO, said: "This contract highlights the breadth of expertise available through hVIVO's integrated platform, supporting clients from preclinical and regulatory strategy through to clinical development and proof-of-concept studies. Increasingly, biotechnology companies are seeking specialist partners that can provide scientific, regulatory and clinical development expertise under one roof, helping them navigate the complex pathway to the clinic more efficiently. We look forward to supporting Decoy as it advances its lead programmes and prepares for future clinical development milestones."

"Our objective is a 'one drug, many viruses, many people' approach," said Rick Pierce, Chief Executive Officer, Decoy Therapeutics. "Viral disease shouldn't require a new drug for every new threat, and it shouldn't take years to reach the people who need it most. We're building D-MAVs as a new category of antiviral, one designed to work across multiple viruses and built from the start for the markets, governments and global health partners who can get them to patients at scale. Our partnership with hVIVO is a critical step toward proving that approach in human studies, and this development framework could potentially support future candidates within our antiviral pipeline."

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Notes to Editors

About Decoy Therapeutics

Decoy Therapeutics is a biotechnology company pioneering Designable Multi-Antivirals (D-MAVs), a new category of antivirals engineered to target shared viral mechanisms, enabling a single, adaptable drug to work across multiple viruses. Built on the proprietary IMP³ACT platform, which combines AI-assisted design and rapid synthesis, Decoy develops peptide antivirals designed to move faster into the clinic and expand what is possible in viral prevention and treatment. The company's lead candidates target multiple respiratory viruses, addressing the health and societal burden of viral disease.

About hVIVO

hVIVO plc (AIM: HVO) is a purpose-built, full-service international clinical development partner and the global leader in human challenge trials, serving seven of the world's ten largest biopharma companies.

The Company has an end-to-end platform designed to bring important medicines to patients faster: spanning preclinical strategy, first‑in‑human studies, Phase II patient trials and specialist laboratory services, delivered through a large participant database, wholly owned sites and laboratories across the UK and Germany.

With a combined Group heritage of more than 100 years, hVIVO delivers an accelerated pathway to clinical proof-of-concept through four integrated service lines: Consulting, Clinical Trials, Human Challenge Trials, and Laboratories.

·    Consulting provides expert-led preclinical and clinical strategy, encompassing non-clinical, clinical, CMC, pharmacokinetics, data management, biostatistics, and regulatory support to guide trial design, execution, and interpretation.

·    Clinical Trials offers Phase I/II CRO services, Phase II/III site services across the UK and Germany, and specialist recruitment through FluCamp, Europe's largest recruitment database.

·    Human Challenge Trials leverages hVIVO's state-of-the-art quarantine facility in London - the largest of its kind worldwide - to deliver fast, controlled, high-quality efficacy data through guaranteed viral exposure.

·    Laboratories provides cutting-edge virology and immunology laboratory services, including biobanking and sample storage, supporting both challenge trials and standalone client studies.