A xenograft model is an animal model used in preclinical research, particularly in oncology. Human tumour cells are implanted into immunocompromised animals (usually mice or rats). Because the animals’ immune system is suppressed, the human cells are not rejected and can grow into a tumour. This ‘Patient-Derived Xenograft’ (PDX) model often closely reflects the characteristics of the original human tumour.
These models are an indispensable tool for testing the efficacy of new cancer medicines before they are used in clinical trials in humans. They allow researchers to investigate the effect of a substance on tumour growth in a living organism and to gather early indications of potential biomarkers. Although CROs primarily conduct clinical trials, understanding the data from these preclinical models is crucial for planning the first trials in humans (Phase I).