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Challenge Agents Matter


During the development of new antiviral compounds and vaccines there are limited options for obtaining meaningful efficacy data before initiating large-scale Phase 3 clinical trials. Data from animal models can often not be meaningfully translated to natural human infection due to inherent differences in viral replication kinetics and poorly comparable immune parameters.

Many Phase 2 clinical field-trials are not geared to obtain statistically meaningful efficacy data given size restrictions on these trials and the frequently limited availability of diseased cohorts, especially for seasonal viruses; failure at Phase 2 may therefore be a product of both cost and complexity. Phase 2 clinical field-trial efficacy data, where not supported by statistically relevant cohorts, may be overinterpreted or subject to Type 1 error, which may in turn lead to over-estimations of performance and an increased chance of late phase failure.

Controlled Human Infection Models (CHIMs) may diminish the odds of bias by providing statistically significant efficacy data regarding outcome measures anticipated to be used in subsequent field trials; including both viral shedding (vAUC) and symptoms (sAUC). Data from CHIM studies are however only as good as the challenge agent used allows.

The clinical trials market from infectious disease segment accounted for USD 5.3 Billion in 2021 owing to growing prevalence of infectious diseases such as coronaviridae, bacterial meningitis, influenza, and T.B. In addition, increasing investment in R&D for novel infectious disease treatments is contributing to growth of this segment.

The increasingly important role of challenge studies in this market is highlighted by several announcements for vaccine discovery and efficacy trials by top tier pharmaceutical companies and research scientists including the pre-F RSV vaccine tested by CHIM, shown to achieve vaccine efficacy of 86.7% (Pfizer) and a recent study by Jochems et al investigating the role of influenza infection leading to secondary bacterial pneumonia, using a “double” experimental human challenge model and systems biology approaches.

The CHIMunomics team comprises world leaders in the CHIM and ID field. Contact us to see how we can help accelerate and optimise your ID pipeline or for investment opportunities to become part of this fast-growing company.

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