Clinical development partner hVIVO plc (AIM: HVO) announced on Wednesday that it has signed a contract with ILiAD Biotechnologies Inc to conduct a pivotal Phase III human challenge trial for the BPZE1 vaccine candidate targeting Bordetella pertussis, the bacterium responsible for whooping cough.

This study will be the world's first pivotal Phase III human challenge trial in Bordetella pertussis, evaluating BPZE1's efficacy in preventing infection compared with the current Tdap standard of care. The trial is expected to enrol more than 500 healthy volunteers through FluCamp, marking the largest human challenge trial undertaken by hVIVO plc to date.

The multi-year contract is anticipated to represent the company's highest-value human challenge trial, with revenue recognition commencing in H1 2026 and the majority expected during 2026 and 2027. hVIVO will also conduct microbiology assays for primary and key secondary endpoints at its Canary Wharf laboratory, following a year of collaboration with ILiAD Biotechnologies to develop the required bacterial assays.

Human challenge trials offer a more efficient route to efficacy data in pertussis due to unpredictable outbreak patterns and high baseline vaccination rates, which limit the feasibility of conventional field studies. Whooping cough remains a significant global health risk, particularly for infants, despite widespread vaccination coverage and is associated with substantial morbidity and mortality.

BPZE1 is a next-generation, live attenuated intranasal vaccine designed to provide durable protection against infection and disease, with the potential to reduce transmission.