An overview of immune safety avatar: mimicking the effects of immunomodulatory therapies on the immune system

Innovative therapeutics like biologicals that modulate the immune system are on the rise. However, their immune-modulating characteristics can also lead sometimes to the induction of adverse effects, by triggering unintended immune reactions. Due to the complexity and target-specificity of such therapeutics, these drug-induced adverse events could remain undetected during non-clinical development, if the test systems are, for example, animal-based, and only emerge in clinical development when tested in humans and subsequently lead to discontinuance of otherwise promising drug candidates. To identify adverse effects on the human immune system at an early stage, new approaches, assays, and technologies are needed. The Innovative Medicine Initiative (IMI) cooperation Immune Safety Avatar (imSAVAR) project aims to develop a tool for integrated non-clinical safety assessment for immune-modulatory new therapeutic drugs and clinical trial applications. To achieve this goal, imSAVAR has relied on the Adverse Outcome Pathway (AOP) framework to gather knowledge in a structured approach and to design, select or develop, when needed, appropriate test systems for prediction of the immune-related adverse outcomes. So far, the imSAVAR consortium has identified the "mode of action" for certain classes of drugs that needed improved risk assessment, including chimeric antigen receptor T cells (CAR T cells), immune checkpoint inhibitors (ICIs), and recombinant proteins (e.g. interleukin [IL]-2), has linked those to their immune-related adverse outcomes and has formulated literature-based immune-related AOPs (irAOPs). Models to measure those immune-specific perturbations were selected, adjusted, or newly developed. The imSAVAR work described in this special issue of The Journal of Immunotoxicology supports our understanding of immune-mediated adverse effects and their early discovery during development to improve the safety of innovative biomedicals.