hVIVO plc

("hVIVO" or the "Company")

Positive results from influenza human challenge study conducted by hVIVO

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, notes the announcement by Cidara Therapeutics, Inc. ("Cidara"), reporting positive interim results from an ongoing human challenge study testing CD388. hVIVO is conducting the Phase 2a single-center, randomised, double-blinded, placebo-controlled trial using its H3N2 Influenza Human Challenge Study Model.

CD388 is Cidara's long-acting drug-Fc conjugate antiviral for the treatment of seasonal influenza. The interim analysis is based on 56 healthy volunteers, with 28 receiving a single dose of CD388 (150 mg) and 28 receiving a placebo. All subjects were then challenged with a H3N2 influenza A challenge agent. Interim results showed a decrease in viral replication in the upper respiratory tract and influenza infection in participants receiving a single dose of CD388 when compared to placebo. CD388 was well-tolerated with no drug -related adverse events observed. The data has established preliminary clinical proof of concept for CD388's ongoing development programme.

hVIVO has three decades of experience and expertise in safely conducting challenge studies across a range of respiratory viruses, including various strains of influenza, respiratory syncytial virus (RSV), human rhinovirus (HRV - common cold virus), COVID-19, asthma, as well as malaria.

Cidara's announcement is available at https://www.cidara.com/news/cidara-therapeutics-announces-promising-interim-phase-2a-data-assessing-the-safety-and-efficacy-of-a-single-dose-of-cd388-in-an-influenza-challenge-model/

Dr Andrew Catchpole, Chief Scientific Officer of hVIVO, said: "hVIVO boasts a world-leading portfolio of human challenge models, and we are delighted to see the positive interim results outlining CD388's efficacy against H3N2 influenza, one of the two subtypes responsible for the annual influenza epidemics. The results are another clear demonstration of the value of human challenge trials in delivering quick efficacy data, de-risking entry into later stage clinical development. Importantly, the data underlined the potential of Cidara's Cloudbreak drug-Fc conjugates, of which CD388 is one example, to be efficacious long-acting therapeutics with universal protection of seasonal and pandemic influenza."

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Notes to Editors

About hVIVO

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 11 human challenge models, with a number of new models under development, to test a broad range of infectious and respiratory disease products. The Company has 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 Cidara Therapeutics

Cidara is developing long-acting therapeutics designed to help improve the standard of care for patients facing serious diseases. The Company's portfolio is comprised of new approaches aimed at transforming existing treatment and prevention paradigms, first with its lead Phase 3 antifungal candidate, rezafungin, in addition to drug-Fc conjugates (DFCs) targeting viral and oncology diseases from Cidara's proprietary Cloudbreak® platform. Cidara is headquartered in San Diego, California. For more information, please visit www.cidara.com.