The National Cancer Center Japan (NCC) has announced the start of a new clinical trial for an anticancer drug prescreened with tumor-bearing mice, saying the use of such mouse models could significantly accelerate the nation’s drug development.

The NCC has a collection of patient-derived xenograft (PDX) mouse models called J-PDX, which are immunodeficient mice that have had the live tumor tissues of patients transplanted onto their backs.

NCC researchers say they can examine a drug candidate’s efficacy by using J-PDX mice much more precisely than using cancer “cell lines” — cancer cells cultured in a petri dish. Conventionally, researchers add a drug candidate to such cultured cells to determine its efficacy before they begin a clinical trial.