Currently, limited options are available for selecting an optimal treatment regimen for a particular patient at a given stage of disease. DRIT is a diagnostic service for predicting treatment outcomes prior to the selection of anticancer drug therapy for individual patients. DRIT quantitatively measures Drug Response Indicator (DRI) expression levels in formalin fixed, paraffin embedded tumor tissue. DRI quantitation in > 500 tumor cells is based on fluorescent dye-labeled monoclonal antibody staining, followed by analysis of digital images using computer-assisted microscopy calibrated to an external standard. Standardization to an external reference allows a high degree of inter-observer, inter-instrumentation reproducibility. DRI chosen for each drug is an indicator of tumor response as related to the mechanism of drug action. This relationship has been verified in vitro with 8-10 cancer cell lines of differing drug sensitivity by correlating drug toxicity (IC₅₀) and DRI expression. For each drug/DRI pairing, a cut off level for the bimodal distribution of sensitive versus resistant tumor is established based on DRI expression level in the tumor.

DRI expression measurement results in classification of the tumor as sensitive or resistant to a particular drug. A tumor classified as sensitive to a drug by DRIT predicts that the patient will respond to treatment, while a tumor that is classified as resistant predicts the patient will be non responsive.

DRIT Flow Diagram