Vaccines and antivirals have been the fundamental pillars in the battle against infectious diseases. Nonetheless, their development is fraught with substantial hurdles, necessitating a protracted and costly journey, frequently marred by a notable rate of failure. The onset of the COVID-19 pandemic brought Human Challenge Trials (HCTs) showcased the significant potential of this research approach in advancing our understanding and assessment of infectious diseases and expediting vaccine development.
“With small biotechs, these human challenge trials offer clear proof-of-concept data, much better than data from animal studies, which can be plagued with translation issues on how it would perform in humans. As for big pharma, human challenge trial data can be used to argue their case for internal funding over other assets in the pipeline,” said Open Orphan’s chief scientific officer Andrew Catchpole.
Human challenge studies have made a remarkable contribution to speeding up the progress of treatments for various diseases, such as malaria, typhoid, cholera, norovirus, and influenza in the past few decades. These trials have also been instrumental in aiding researchers determine which candidate vaccines are most promising for advancement to phase 3 clinical trials—a crucial step that typically entails the involvement of thousands of volunteers.
In the realm of medical research, where science and ethics intersect, HCTs stand as a powerful symbol of collective pursuit of knowledge and commitment to improving public health.
All risks in human challenge studies ought to be minimised to the greatest extent possible, while focusing on not excessively compromising the potential research benefits. This requires consultation with scientific experts, prospective participants, and the broader community. Through these consultations, it becomes possible to assess and determine the acceptable level of residual risks, ensuring that they are justified by the expected research benefits. This collaborative and ethical approach helps uphold the principles of transparency, informed consent, and the responsible advancement of scientific knowledge in the context of human challenge studies.
Despite the significant inroads made by human challenge trials (HCTs) in infectious disease research, however, we do not yet have codified regulations pertaining to HCTs. Furthermore, there is a visible lack of regulatory guidance related to standardising approaches to HCTs among different regulatory bodies.
As indicated by a study published in The Lancet Infectious Diseases journal, recent assessments of the ethical frameworks concerning human challenge studies have emphasised on striking a balance between the acceptable risk associated with exposing individuals to experimental interventions or pathogens for vaccine development and the social value or public health benefits. This delicate equilibrium ensures that the ethical conduct of these studies prioritises the wellbeing of participants while advancing vital research with the potential to benefit public health and combat infectious diseases effectively.
The article in this issue on “Human Challenge Trials - Establishing early risk-benefit in development of vaccines and therapies for infectious diseases” by Bruno Speder, VP Regulatory Affairs, Poolbeg Pharma explains the role of HCTs in the testing and development of novel antivirals and vaccines.