Decoy Therapeutics partners with hVIVO to advance lead D-MAV(TM) candidate into the clinic. 2 June 2026 Decoy Therapeutics Inc., a pre-clinical-stage biotechnology company pioneering a new category of antivirals, today announced the execution of a strategic development initiative designed to support the advancement of the company's Designable Multi-Antiviral (D-MAV) candidates into Phase 1 first-in-human and Phase 2a human proof-of-concept studies. Decoy has engaged hVIVO, a purpose-built, full-service international clinical development partner and global leader in human challenge studies, to support translational modeling, regulatory strategy, clinical development planning, and Phase 1 and Phase 2a human proof-of-concept study preparation for Decoy's lead D-MAV candidate. The outputs will serve as a future rapid preclinical and clinical template for Decoy's growing portfolio of D-MAV drug candidates. Decoy believes its platform architecture may allow for similar clinical trial designs across multiple D-MAV candidates, subject to regulatory feedback. The initiative brings together Decoy's proprietary IMP[3]ACT(TM) platform for D-MAV discovery, which uses AI-enabled peptide design running on Google Cloud, with the translational, regulatory, clinical development and infectious disease drug development expertise and substantial capabilities of hVIVO. The collaboration is intended to support the clinical advancement of Decoy's lead respiratory antiviral candidates, which are designed to target shared viral mechanisms across multiple respiratory viruses using a single adaptable therapeutic approach. "Traditional antiviral development has largely followed a one-drug, one-virus model," said Barbara Hibner, Founder and Chief Scientific Officer of Decoy Therapeutics. "Our IMP[3]ACT platform was built to move faster than that. By combining AI-enabled design with rapid synthesis, we are working to take a D-MAV candidate from concept toward the clinic on a timeline that keeps pace with how viruses actually evolve." Under the agreement, hVIVO will support Decoy across translational modeling, 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 includes support for regulatory interactions with both the European Medicines Agency (EMA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Decoy intends to conduct early proof-of-concept and likely follow-on studies with hVIVO, given its track record in human challenge trials. Decoy also plans to pursue US registration of its D-MAVs with the FDA. Yamin 'Mo' Khan, Chief Executive Officer of hVIVO, said "The antiviral landscape continues to evolve as sponsors seek new approaches to address respiratory viruses and strengthen pandemic preparedness. Decoy's programmes represent a differentiated approach, and we are pleased to be supporting the company as it progresses towards the clinic. This collaboration highlights the growing demand for integrated development partners that can support biotechnology companies from early development strategy through to clinical execution." In parallel, Decoy intends to utilize outputs generated through hVIVO's consultancy program to inform clinical development strategy, first-in-human dose selection, translational pharmacology planning, challenge study design considerations, and Phase 2a human proof-of-concept readiness activities. The combined effort is designed to support Decoy's transition into the clinic by aligning translational science, regulatory planning, and early clinical execution around a unified development pathway. "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," said Rick Pierce, Chief Executive Officer, Decoy Therapeutics. "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." Decoy's lead programs are focused on respiratory viral infections and are designed to support broader preparedness strategies against evolving and emerging viral threats. The company believes its platform architecture may enable more rapid optimization and adaptation compared to traditional antiviral development approaches. The company expects the collaboration activities to support filing IND/CTAs, translational package development, regulatory engagement preparation, and the design of future phase 1 and human proof-of-concept studies. 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 IMP[3]ACT 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. Forward Looking Statements This press release contains "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995 regarding Decoy, including expected achievement of milestones for its lead asset and future prospects of Decoy. These statements may discuss goals, intentions and expectations as to future plans, trends, events, results of operations or financial condition, or otherwise, based on current beliefs of the management of Decoy, as well as assumptions made by, and information currently available to, management. Forward-looking statements generally include statements that are predictive in nature and depend upon or refer to future events or conditions, and include words such as "may," "will," "can," "should," "would," "expect," "anticipate," "plan," "likely," "believe," "estimate," "project," "intend," and other similar expressions. Statements that are not historical facts are forward-looking statements. Forward-looking statements are based on current beliefs and assumptions that are subject to risks and uncertainties and are not guarantees of future performance. Actual results could differ materially from those contained in any forward-looking statement as a result of various factors, including, without limitation: the risk that the Company will not obtain sufficient financing to execute on their business plans and risks related to Decoy's products and development plans, including unanticipated issues with any IND application process and the potential of the IMP3ACT(TM) platform. Readers are urged to carefully review and consider the various disclosures made by the Company in its reports filed with the SEC, including its Annual Report on Form 10-K for the fiscal year ended December 31, 2025, as revised or supplemented by its Quarterly Reports on Form 10-Q and other documents filed with the SEC. If one or more of these risks or uncertainties materialize, or if the underlying assumptions prove incorrect, Decoy's actual results may vary materially from those expected or projected. 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.

hVIVO #HVO - Result of AGM. London, UK - 13 May 2026, hVIVO plc (AIM: HVO), a purpose-built, full-service international clinical development partner and the world leader in human challenge trials, announces that all resolutions put to shareholders at the Company's Annual General Meeting ('AGM') held earlier today were duly passed. The voting results of the AGM will be published on the Company website shortly: https://hvivo.com/company-documents/ For further information please contact: | hVIVO plc | +44 (0)20 7756 1300 | | Yamin 'Mo' Khan, Chief Executive Officer Stephen Pinkerton, Chief Financial Officer | / | | Cavendish Capital Markets Limited (Nominated Adviser and Joint Broker) | +44 (0)20 7220 0500 | | Geoff Nash, Callum Davidson Trisyia Jamaludin, Harriet Ward Nigel Birks - Life Science Specialist Sales Louise Talbot - Sales | / | | Peel Hunt LLP (Joint Broker) | +44 (0)20 7418 8900 | | James Steel, Dr Christopher Golden | / | | Davy (Joint Broker) | +353 (0) 1 679 6363 | | Anthony Farrell, Niall Gilchrist | / | | ICR Healthcare (Financial PR & IR) Mary-Jane Elliott / Stephanie Cuthbert / Phillip Marriage / Louis Ashe-Jepson | [email protected] |