Response Genetics to Announce Bladder, Colon and Colorectal Cancer Results at the 2009 American Society of Clinical Oncology Annual Meeting

Business Wire, May 28, 2009

New Data Support the Use of Gene Expression Panels to Help Guide Chemotherapy Selection

LOS ANGELES -- Response Genetics Inc. (Nasdaq:RGDX), a company focused on the development and sale of molecular diagnostic tests for cancer, will announce the results of studies in bladder cancer, colon cancer and colorectal cancer that identify genes associated with positive chemotherapy outcome and tumor recurrence. Results will be presented during the 2009 American Society of Clinical Oncology (ASCO) Annual Meeting in Orlando, which will be held May 29 to June 2.

“The use of predictive biomarkers in the clinical setting is helping physicians select the best chemotherapy option for each patient,” said Kathleen Danenberg, president and CEO of Response Genetics. “Our studies present additional evidence to underscore the effectiveness of our ResponseDX™ tests in personalized cancer care.”

All studies presented used technology developed by Response Genetics to isolate RNA from formalin-fixed, paraffin-embedded (FFPE) archived tissue for quantitative RT-PCR analysis of gene expression. Following is a summary of presentations:

Friday, May 29, 2:00 to 6:00 p.m.; Level 2, West Hall F5

Abstract No. 5026: Correlation of multidrug-resistance 1 (MDR1) gene expression levels and outcome to adjuvant cisplatin/methotrexate (MTX)-based chemotherapy in patients enrolled in the AUO-AB 05/95 phase III trial.

This study investigated the relationship between MDR1 gene expression and excision repair cross-complementing factor 1 (ERCC1) gene expression to outcome in patients with locally advanced bladder cancer treated with adjuvant therapy, including cisplatin/MTX or MTX, vinblastine, epirubicin, and cisplatin (M-VEC). Results show that both genes exhibit a significant correlation to positive clinical outcome, and together, identified three patient subgroups with significant differences in overall survival and progression-free survival. These data confirm the importance of ERCC1 as a predictor of response for platin-based chemotherapy. They also identify MDR1 as a promising biomarker to predict the outcome of adjuvant cisplatin/MTX-based adjuvant chemotherapy. This study provides the foundation for development of a new diagnostic test for improving chemotherapy of bladder cancer.

Sunday, May 31, 8:00 to 12:00 a.m.; Level 2, West Hall C

Abstract No: 4056: Wt KRAS and gene expression levels of VEGFR2, EGFR and ERCC-1 associated with progression-free survival (PFS) in patients (pts) with metastatic colorectal cancer (mCRC) treated with first-line 5-FU or capecitabine with oxaliplatin and bevacizumab (FOLFOX/BV or XELOX/BV).

This study evaluated KRAS status and expression of genes involved in angiogenesis, DNA repair and 5-FU metabolism to identify predictors of outcome in patients treated with FOLFOX/BV or XELOX/BV. These genes included VEGF, VEGF-receptor 2, Cox-2, IL 6 and 8, chemokine-receptors 1 and 2, EGFR and ERCC-1. Results show that response rate (RR) and PFS were significantly longer for patients with wt KRAS, compared to patients with mutant KRAS. High EGFR, high VEGFR2 and low ERCC1 were associated with longer PFS, compared to low EGFR, low VEGFR2 and high ERCC1. To our knowledge, this is the first report showing an association between KRAS status, gene expression levels of VEGFR2, ERCC-1 and EGFR with clinical outcome to FOLFOX/BV therapy in patients with mCRC. These results suggest new gene combinations may help predict clinical benefit from chemotherapy of CRC.

Sunday, May 31, 8:00 to 12:00 a.m.; Level 2, West Hall C

Abstract No: 4040: VEGF and VEGFR1 gene expression levels and tumor recurrence in adjuvant colon cancer.

Gene expression levels of angiogenesis regulators (COX-2, EGFR, VEGF, VEGFR1, VEGFR2 and IL-8) were tested to determine whether they could predict the risk of tumor recurrence in stage II and stage III colon cancer patients treated with adjuvant chemotherapy. Patients with lower VEGF gene expression and lower VEGFR1 gene expression levels had significantly longer time to tumor recurrence, compared to patients with higher VEGF and higher VEGFR1 gene expression levels. These results show that VEGF and VEGFR1 gene expression levels may predict tumor recurrence risk in colon cancer patients and help identify patients likely to benefit from adjuvant chemotherapy.

About Response Genetics, Inc.

Response Genetics, Inc. (“RGI”) (the “Company”) (Nasdaq:RGDX) is focused on the development and sale of molecular diagnostic tests for cancer. RGI’s technologies enable extraction and analysis of genetic information from genes derived from tumor samples stored as formalin-fixed and paraffin-embedded specimens. In addition to diagnostic testing services, RGI generates revenue from the sales of its proprietary analytical pharmacogenomic testing services of clinical trial specimens to the pharmaceutical industry. The Company was founded in 1999 and its principal headquarters are located in Los Angeles, California. For more information, please visit www.responsegenetics.com.