ALBUQUERQUE, N.M., Dec. 13 /PRNewswire/ -- An initial validation study
presented by Exagen Diagnostics at the San Antonio Breast Cancer Symposium
suggests it may soon be possible to distinguish good prognosis from poor
prognosis in any newly diagnosed breast cancer patient based on DNA changes in
the patient's tumor. Those patients identified as having a very good
prognosis may do well without chemotherapy or hormonal therapy after their
tumors have been removed.
In a retrospective study of 308 patients conducted with the University of
New Mexico Cancer Research and Treatment Center at the Health Sciences Center,
Exagen Diagnostics, an emerging leader in the rapid identification and
productization of practical, genomic markers for prognostic testing, reported
the discovery of two, 3-gene sets of markers that were prognostic in testing
archived specimens from hormone receptor (HR)-positive and hormone
receptor-negative patients, respectively. These two sets of markers form a
panel for use in testing tumor tissue from breast cancer patients, providing a
same- or next-day result.
In independent test sets, each of the 3-gene markers accurately identified
91 percent of HR-negative and HR-positive specimens from patients that did not
experience recurrence of disease. In patients that were also node negative,
the negative predictive value was 100 percent (e.g., 100 percent of patients
identified by these tests had a good prognosis clinically).
The study population consisted of white and Hispanic patients with
invasive ductal carcinoma that were diagnosed between 1986 and 1999 at the
University of New Mexico Health Sciences Center. A minimum of four years of
follow-up clinical information was available for each of the patients, with an
average follow-up of 8.9 years. Poor prognosis was clinically defined as
development of recurrence, as evidenced by either distant metastasis or death
from breast cancer. Good prognosis was clinically defined as the absence of
recurrence (or death from breast cancer) as of the last date of follow-up.
"With this approach, we are seeking to define a new standard of care by
becoming the first company to offer a prognostic panel of tests that examines
the patient's tumor tissue to detect changes in DNA copy number in any
patient. This is a more practical method than currently available tests using
RNA," said Waneta Tuttle, Ph.D., Exagen CEO.
"Today, we are treating almost any woman as though her cancer is
aggressive, which puts patients who don't actually need treatment at risk for
side-effects of therapy that is not necessary," explains Ian Rabinowitz, M.D.,
the primary UNM clinician involved in Exagen's initial study. "For early
stage breast cancer there are about 70 to 80 percent of patients who are
cancer-free and don't actually require therapy after they receive a
lumpectomy. At this point in time, we have no way of identifying which
patients fall into that category. So, the advantage of a technology such as
Exagen's prognostic tests, once it is further validated, is that we can better
identify patients that have a very good prognosis and potentially don't
actually require therapy," he said.
The study was conducted using a proprietary "pattern of genomic
amplification" FISH (e.g., fluorescent in situ hybridization) test or PGA
FISH(TM). Due to the small number of markers in each reagent set, Exagen is
uniquely able to implement these tests with PGA FISH technology, making them
readily usable by any FISH-testing laboratory. Exagen's discovery technology
is based on a mathematical approach that enables the company to examine
25,000 genes with no "preference" for one gene over another to define the
best, small combination of genes for a specific testing purpose.
About Exagen Diagnostics, Inc.
As an emerging leader in prognostic testing, Exagen Diagnostics is
uniquely able to define small sets of genomic markers that are more accurate
than other approaches, whether for breast cancer, infectious disease or other
indications. Exagen's proprietary discovery and implementation technologies
enable the rapid identification and productization of optimized DNA or RNA
genomic marker sets for prognostic or predictive testing, either for
diagnostic testing by reference laboratories or for pharmaceutical R&D
purposes. For more information, visit www.exagendiagnostics.com.
SOURCE Exagen Diagnostics, Inc.