The need for guidance on properly designing, developing and manufacturing controlled human infection challenge strains/agents used in clinical studies is covered. Currently there are differences across countries in how these challenge agents are classified and regulated. Efforts to establish international standards and best practices around the selection, characterization, manufacturing, quality control and storage of challenge agents are discussed.

Key takeaways

  • The importance of rigorous characterization and well-defined manufacturing processes to ensure participant safety and reliable study data.
  • Following GMP principles as much as possible during manufacturing, even for non-drug/biologic agents.
  • How regulatory requirements depend on the specific agent, with more stringent standards for higher-risk agents like viruses.
  • Critical considerations like formulation, stability testing, release criteria, environmental monitoring and decontamination.
  • Real-world examples highlighting challenges and strategies for agents like SARS-CoV-2, hookworms and malaria parasites.

Explore this paper to gain full insights on establishing robust international guidelines for challenge agent development and manufacturing. Find complete perspectives on critical quality principles, GMPs, regulatory strategies and more.


Dr Paula Salmikangas

Director of Biopharmaceuticals and ATMP

Dr Pieter Neels

NDA Advisory Board Member


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