positive Phase III clinical data

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LOS ANGELES, July 9 /PRNewswire-FirstCall/ -- Response Genetics, Inc. today announced that positive Phase III clinical data published in the July 1 issue of the Journal of Clinical Oncology suggests that low expression of the biomarker Excision-Repair Cross-Complementing 1 (ERCC-1) in patient biopsies with advanced non-small cell lung cancer (NSCLC) predicts for sensitivity to cisplatin-based chemotherapy. ERCC-1 is an enzyme involved in repair of DNA strand breaks such as those caused by cisplatin. The analysis of ERCC-1 levels in this study was conducted by Response Genetics using its RGI-1 technology. Data from previous studies published by the Company in Clinical Cancer Research 2002 and Annals of Oncology 2006 showing that ERCC-1 was associated with tumor sensitivity to cisplatin formed the basis for the present study. This is the first prospective study using a biomarker to predict chemotherapy response in lung cancer. These findings support the use of measurement of ERCC-1 for individualizing therapies for lung cancer patients.

The Phase III multicenter, randomized study was designed to determine the overall response rate (complete plus partial responses) of patients with stage IIIb or IV NSCLC to cisplatin-based therapy by determining levels of the biomarker ERCC-1 mRNA in their paraffin-embedded tissue biopsy before administering treatment. Patients were prospectively assigned treatment to a cisplatin or non-cisplatin-based chemotherapy depending on whether the ERCC-1 gene expression in their tumor sample was above or below a specific threshold. Patients were assigned to one of two arms in this trial. The control arm consisted of all patients receiving cisplatin-based therapy. Patients in the "genotypic" arm were separated by levels of ERCC-1. Cisplatin-based therapy (docetaxel/cisplatin) was assigned to patients with low levels of ERCC-1, while non cisplatin-based therapy (docetaxel/gemcitabine) was assigned to patients with high levels of ERCC-1.

The response rate to cisplatin-based therapy for patients with low ERCC-1 was 1.76 times higher than for patients in the control arm. Also, patients with high levels of ERCC-1 who were treated with non-cisplatin based therapy had a 1.38 fold increase in response rate compared with the control arm. A statistically significant benefit in objective response (n=107, p=.024) was observed in the "genotypic" arm of the study.

The full article will be made available on Response Genetics' website later this week.

"There is tremendous value in better understanding pharmacogenomics to tailor treatment and improve patient outcomes," said Kathleen Danenberg, President and CEO of Response Genetics. "These results along with previous studies provide strong evidence that by prospectively defining patients' ERCC- 1 levels, physicians can make a more informed choice on the suitability of cisplatin-based chemotherapy for lung cancer patients"

About the study

From August 2001 to October 2005, 444 stage IV patients with NSCLC were enrolled at 24 European centers. Patients were randomly assigned in a 1:2 ratio to either control or genotypic arm before ERCC-1 assessment. Patients in the control arm received docetaxel plus cisplatin. In the genotypic arm, patients with low ERCC-1 levels received docetaxel plus cisplatin, and those with high levels received docetaxel plus gemcitabine. The primary objective was the overall objective response rate.

Of the 444 patients enrolled, 78 (17.6%) went off study before receiving one cycle of chemotherapy, mainly due to insufficient tumor tissue for ERCC-1 mRNA assessment. Of the remaining 346 patients assessable for response, a statistically significant benefit in objective response was observed in 107 patients on the genotypic arm (50.7%, p=.024), and 53 patients in the control arm (39.3%).

About Response Genetics, Inc.

Response Genetics, Inc. ("RGI") is engaged in the research and development of pharmacogenomic cancer diagnostic tests based on its proprietary and patented technologies. RGI's technologies enable extraction and analysis of genetic information from genes derived from tumor samples stored as formalin-fixed and paraffin embedded specimens. RGI currently generates revenue primarily 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.

Forward Looking Statement Notice

Except for the historical information contained herein