Genomic Health, Inc.
(Nasdaq: GHDX) today announced the results of several studies looking at
the roles and relationships of genes measured by the company's Oncotype DX
breast cancer assay, including an analysis of more than 10,000
node-negative tumors indicating that all 21 genes impact the assessment of
an individual woman's tumor. This research was presented at the 29th Annual
San Antonio Breast Cancer Symposium.
Oncotype DX measures the expression of 16 cancer-related genes plus 5
reference genes of an individual tumor to generate a "Recurrence Score" to
quantify risk of recurrence and likelihood of response to chemotherapy. To
assess the degree to which components of this multi-gene assay influence
the Recurrence Score, researchers measured expression of the 16 individual
cancer genes relative to reference genes in 10,618 tumor specimens on a
scale of 0 to 15, where a one-unit increment is associated with a twofold
change in expression. Results suggest that every cancer gene used in the
Oncotype DX 21-gene panel impacts the Recurrence Score due to the
potentially large variation in quantitative expression for each gene in
different patients. The study found this result even though expression of
certain genes and gene families; including ER, HER2 and a group of five
genes linked to proliferation, have the largest coefficients used in
calculating the Recurrence Score.
"Our ongoing clinical work is generating an abundance of useful and
important data, as evidenced by the collective findings presented in San
Antonio," said Steven Shak, M.D., chief medical officer of Genomic Health.
"With standardized quantitative measurements now analyzed in 20,000-plus
tumor samples, Genomic Health has the unique opportunity to generate and
share knowledge about the biology of breast cancer, which may lead to the
development of more effective individualized treatment for breast cancer
patients."
Study of 20,000 Samples Finds Heterogeneity in Three Breast Cancer
Subtypes
A second study, conducted in the same cohort of 10,618 tumor samples
plus an additional 9,432 samples analyzed recently for a total of 20,050
samples, used RT-PCR analysis as measured by Oncotype DX to identify the
breast cancer subtypes revealed by a standardized quantitative expression
assay. Three major subtypes of breast cancer were identified: patients with
ER-positive and HER2-negative disease; those with HER2-positive disease;
and those negative for ER, HER2 and the progesterone receptor (PR), or
triple negative breast cancer. These three subtypes have been proposed
previously, but the standardized quantitative Oncotype DX test revealed
that there is significant heterogeneity within each subtype that is likely
to be important for individualizing treatment. These results may help
explain why patients with each subtype respond so differently to treatment,
and underscore the importance of standardized measurement of gene
expression as a clinical tool.
Study of 20,000 Samples Shows Proliferation Genes and Hormone Genes
Provide Independent Assessment
In a third study using the same 20,050 tumor samples, Genomic Health
investigators examined whether genes linked to proliferation were
associated with hormone and growth factor receptors. The hormone receptor
genes, ER and PR, as well as the HER2 growth factor receptor gene, are
well-known markers for disease risk and treatment success; however, the
analysis found that the expression of the proliferation genes was largely
independent of the hormone and growth factor receptor genes. These results
may explain why distinct contributions of multiple genes are required to
characterize the biology and treatment of individual breast cancers.
Kaiser, NSABP Study Finds ER Predictive, PR Prognostic
Separately, Genomic Health, the Pittsburgh-based National Surgical
Adjuvant Breast and Bowel Project (NSABP) and Kaiser Permanente presented
findings from a study that assessed whether PR expression and ER expression
were associated with disease prognosis or were predictive of response to
adjuvant therapy with tamoxifen.
Researchers used Oncotype DX to measure the association between PR and
ER expression and outcomes in more than 1,000 patients from two previously
conducted Kaiser and NSABP studies. In both studies, expression of ER was
associated with how a patient benefits from treatment with tamoxifen, but
was not significantly associated with prognosis in untreated patients,
indicating that it is a predictive factor. In contrast, these findings
showed PR to be a characteristic of disease progression, or prognostic
factor, but not predictive of benefit from tamoxifen. These results
indicate that not all women with estrogen receptor-positive breast cancer
benefit equally from tamoxifen.
"Over the years there have been conflicting reports about the relative
roles of ER and PR as prognostic and/or predictive factors in breast
cancer," said Norman Wolmark, M.D., chairman of the National Surgical
Adjuvant Breast and Bowel Project (NSABP), and the Department of Human
Oncology at Allegheny General Hospital in Pittsburgh, Pennsylvania. "Thanks
to these findings, which suggest very distinct roles, we believe we can
better chart how a woman's disease will progress and whether she's likely
to respond to hormone therapy based on her individual quantitative PR and
ER measurements."
About Oncotype DX
Oncotype DX represents the first diagnostic multi-gene expression test
service commercially available that has clinical evidence validating its
ability to predict the likelihood of breast cancer recurrence, the
likelihood of patient survival within 10 years of diagnosis and the
likelihood of chemotherapy benefit. Oncotype DX has been extensively
evaluated in multiple independent studies involving more than 2,600 breast
cancer patients, including a large validation study published in The New
England Journal of Medicine and a chemotherapy benefit study published in
the Journal of Clinical Oncology. For more information about Oncotype DX,
please visit oncotypedx.
About Genomic Health
Genomic Health, Inc. (Nasdaq: GHDX) is a life science company focused
on the development and commercialization of genomic-based clinical
laboratory services for cancer that allow physicians and patients to make
individualized treatment decisions. In 2004, Genomic Health launched its
first test service, Oncotype DX(TM), which has been shown to predict the
likelihood of breast cancer recurrence and the likelihood of chemotherapy
benefit in early-stage breast cancer patients. The company was founded in
2000 and is located in Redwood City, California. For more information, please visit genomichealth.
Forward Looking Statements
This press release contains forward-looking statements within the
meaning of the Private Securities Litigation Reform Act of 1995, including
statements relating to the conclusions suggested by research results, the
continued usefulness and importance of data generated by ongoing clinical
work, the potential for Genomic Health to develop more effective
individualized treatments for breast cancer patients, the significance of
various clinical outcomes and possible future uses for Oncotype DX, Genomic
Health's expectations regarding additional studies and expansion of the
clinical utility of Oncotype DX, its potential effect on clinical practice
and treatment decisions for patients, and the applicability of clinical
study results to actual outcomes. Forward-looking statements are subject to
risks and uncertainties that could cause actual results to differ
materially. These risks and uncertainties include the risks set forth in
our Quarterly Report on Form 10-Q for the quarter ended September 30, 2006,
which is on file with the Securities and Exchange Commission and is
available on the SEC's website at sec. These forward-looking
statements speak only as of the date hereof. We disclaim any obligation to
update these forward-looking statements.
Genomic Health, Inc.
genomichealth
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