PDX Model CROs: Patient-Derived Xenograft Studies

About PDX Models

Patient-derived xenograft (PDX) models are created by implanting tumor tissue from patients directly into immunodeficient mice. Because they are passaged as tissue rather than grown as cell lines, they keep more of the original tumor histology, heterogeneity and genetics, which makes them a better predictor of clinical response than many cell-line xenografts.

Most CROs offering PDX work hold banks of characterized models with genomic, transcriptomic and treatment-history data, so sponsors can choose models carrying a specific mutation or resistance profile. Population-style "mouse clinical trials" test a drug across many models, often with one or a few animals per model, to see which tumor types respond and why.

Two limits are worth planning for. Human stroma is gradually replaced by mouse stroma, and without a functional immune system, immuno-oncology agents need humanized-mouse PDX or syngeneic models instead. Growth rates also vary widely between models, so lead time to study start depends on which ones you choose.

Questions to ask when choosing a PDX Models CRO

• How many models do you hold for our indication, and what molecular and treatment-history data come with each?
• At what passage are models used, and how do you confirm they still match the original tumor?
• What are the take rate and typical time to enrollment for the models we are interested in?
• Do you offer humanized-mouse PDX for immuno-oncology work?
• Can you run a mouse clinical trial design, and how do you analyze response across models?