Direct In Vivo Xenograft Tumor Model for Predicting Chemotherapeutic Drug Response in Cancer Patients

It is estimated that the development of a new anticancer agent costs US$800 million to 1 billion and takes more than a decade between conception and approval.1 However, 90% of novel antineoplastic drugs fail in the clinic despite evidence of antitumor efficacy in classical preclinical models.2 This raises serious concerns as to whether such models are predictive of drug efficacy in humans, particularly in the current era of new targeted therapies, and supports the development of alternative approaches. Clinical Pharmacology & Therapeutics (2009); 85, 2, 217–221 doi:10.1038/clpt.2008.200