Study results of Pathwork Diagnostics's Tissue of Origin Test presented at ASCO 2011

Pathwork Diagnostics, Inc., a privately held molecular diagnostics company focused on oncology, announced today that results from a decision impact study of its Tissue of Origin Test were presented this weekend at the ASCO 2011 Gastrointestinal Cancers Symposium in San Francisco. In the study of 111 cases derived from more than 65 academic and community practices, after receiving the Tissue of Origin Test results, the determination of the primary diagnosis site and treatment management was changed in more than half of patients.

“Effect of a gene expression-based tissue of origin test's impact on patient management for difficult-to-diagnose primary cancers”

"This study confirms that in metastatic cancer patients, the test provides useful information that influences the primary diagnosis site in more than 50% of patients and alters cancer-specific management in even more patients," commented John Hornberger, M.D., M.S., CEO/President of Cedar Associates LLC and Principal Investigator of the study. "This rigorous study has provided important data regarding the Tissue of Origin Test as used in routine clinical practice."

The poster, "Effect of a gene expression-based tissue of origin test's impact on patient management for difficult-to-diagnose primary cancers," was authored by Drs. John Hornberger, Mahul Amin, Gauri Varadhachary, W. David Henner and J. Scott Nystrom (Poster Board #A104; General Poster Session Saturday, January 22).

An important step for a novel test is assessing its clinical utility and real-world effect on diagnosis and patient management. The study collected data from 66 participating physicians who have ordered the Pathwork Tissue of Origin Test for 111 patients with difficult-to-diagnose primary cancers. A detailed survey interview was conducted using both a web-based questionnaire and a confirmatory telephone interview with the physicians, including questions regarding their working diagnoses, diagnostic procedures ordered and treatment recommendations prior to and after Tissue of Origin Test results.

Study results indicated that most patients had undergone extensive evaluation including multiple imaging tests and average of 10 immunohistochemistry tests prior to gene expression analysis. After receiving the Tissue of Origin Test results, determination of the primary diagnosis site was changed in 54% of patients and a change in any aspect of cancer-specific management resulted for 68% of patients. Two-thirds of physicians agreed that the test results were clinically useful in their care of their patients.

Requiring very small amounts of FFPE tumor tissue, the Tissue of Origin Test measures the gene expression levels in more than 2,000 genes and compares the gene expression pattern of the specimen to that of 15 tissues in the test database, to indicate the most likely match.

A large validation and reproducibility study published in this month's Journal of Molecular Diagnostics (JMD) showed that the Tissue of Origin Test can assist in accurately and reliably identifying the origin of metastatic or poorly differentiated tumors using FFPE tissue, which is the most common clinical specimen type used in testing of cancer tumors.

The Pathwork Tissue of Origin Test is the only FDA-cleared molecular diagnostic test for tissue of origin and the most rigorously validated test of its kind. The test is available through the Pathwork Diagnostics Laboratory.