hVIVO plc

("hVIVO" or the "Company")

Phase I results for Imutex's mosquito vaccine candidate published in leading peer-reviewed journal

hVIVO plc (AIM & Euronext: HVO) (formerly Open Orphan plc), a rapidly growing specialist contract research organisation (CRO) and world leader in testing infectious and respiratory disease products using human challenge clinical trials, announces publication of previously reported positive data from a first-in-human Phase I clinical study evaluating the safety and immunogenicity of AGS-v PLUS. The data has been published in eBioMedicine,¹ a peer-reviewed open access biomedical journal part of The Lancet Discovery Science.

AGS-v PLUS is a vaccine candidate against arboviral diseases that targets the saliva of the mosquito rather than the pathogens carried by the mosquito. AGS-v PLUS is owned by Imutex Ltd, a joint venture with PepTcell Limited (the parent company of ConserV Bioscience Ltd), in which hVIVO has a 49% shareholding.

AGS-v PLUS vaccine candidate has a novel proposed dual action mechanism of preventing infection in humans whilst controlling the mosquito population through affecting reproduction. AGS-v PLUS contains five synthetic peptides that originate from proteins found in the saliva of mosquitoes. The published manuscript shows data from the study conducted at the University of Maryland School of Medicine and sponsored by NIAID-NIH, demonstrating that all AGS-v PLUS formulations evaluated (non-adjuvanted or adjuvanted in alhydrogel or Montanide ISA-51) were well tolerated with no serious adverse events experienced, and that they generated a robust cellular and humoral immune response in participants, the formulation in Montanide ISA-51 being the most immunogenic. Moreover, the immune response mounted against AGS-v PLUS was shown to reduce infectivity of Zika virus in vitro.

Mosquito-borne diseases include Zika, West Nile, chikungunya, dengue, yellow fever, and malaria amongst others. There are ~360 million cases of and more than 600,000 deaths from mosquito-borne diseases annually, although the true burden is likely underestimated. A vaccine efficacious against multiple mosquito-borne diseases could significantly impact public health.

Yamin 'Mo' Khan, Chief Executive Officer of hVIVO, said: "It is encouraging to see the results from Imutex's first-in-human Phase 1 trial for AGS-v PLUS published in eBioMedicine. The data demonstrated that AGS-v PLUS was well tolerated and generated a robust immune response in participants, with no serious adverse events. The next steps will be to determine if these findings translate into clinical efficacy against mosquito-borne diseases, which inflict a severe burden on public health systems around the world."

1. "Safety and immunogenicity of AGS-V plus, a mosquito saliva peptide vaccine against arboviral diseases: A randomized, double-blind, placebo-controlled phase 1 trial," by Friedman-Klabanoff, D.A.J. et al. (2022) is available in eBioMedicine, part of The Lancet, 86, p. 104375. DOI: https://doi.org/10.1016/j.ebiom.2022.104375

2. Institute for Health Metrics and Evaluation (IHME). Global Burden of Disease 2019 Cause and Risk Summary: Malaria, Dengue, Yellow Fever, Zika; 2020. Accessed April 6, 2021.

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Notes to Editors

hVIVO plc (ticker: HVO) (formerly Open Orphan plc) is a rapidly growing specialist contract research organisation (CRO) and the world leader in testing infectious and respiratory disease vaccines and therapeutics using human challenge clinical trials. The Group provides end-to-end early clinical development services to its large, established and growing repeat client base, which includes four of the top 10 largest global biopharma companies.

The Group's fast-growing services business includes a unique portfolio of 10+ human challenge models to test a broad range of infectious and respiratory disease products, world class challenge agent manufacturing, specialist drug development and clinical consultancy services via its Venn Life Sciences brand, and a lab offering via its hLAB brand, which includes virology, immunology biomarker and molecular testing. The Group offers additional clinical field trial services such as patient recruitment and clinical trial site services.

hVIVO runs challenge studies in London from its Whitechapel quarantine clinic, its state-of-the-art QMB clinic with its highly specialised on-site virology and immunology laboratory, and its clinic in Plumbers Row. To recruit volunteers / patients for its studies, the Company leverages its unique clinical trial recruitment capacity via its FluCamp volunteer screening facilities in London and Manchester.

About PepTcell Limited

PepTcell brings safe, effective, and low-cost treatments to patients, in the shortest time possible, to radically improve human health in major disease areas. Through its subsidiary ConserV Bioscience Limited, PepTcell develops vaccines to a broad range of infectious diseases. ConserV Bioscience is a late-stage vaccine development company focused on advancing safe and effective vaccines that protect against endemic and emergent infectious diseases. They use a novel in silico proprietary platform to identify highly conserved regions in the proteome that contain a high number of reactive T-cell epitopes with extensive HLA coverage. These regions are then used as antigens and are delivered using the most appropriate method for the combination of antigens and the disease, for example, as synthetic peptides or encoded in mRNA. This approach has consistently identified promising vaccine candidates which have demonstrated immunogenic responses in pre-clinical validation studies and have achieved mid- and late-stage clinical milestones.

www.conservbio.com