Studies Highlight the Ability of VeraTag™ Assays to Identify
Sub-Populations Within “HER2 Positive” Patient Groups
Monogram Biosciences, Inc. (Nasdaq:MGRM) today announced results from
three separate studies at the American Society for Clinical Oncology
(ASCO) meeting in Orlando on the use of HERmark® and the VeraTag™
technology to identify distinct sub-populations of patient with
HER-positive disease. Monogram’s unique measures of HER family protein
levels resulted in improved correlations with the response to
trastuzumab and with the histopathologic characteristics of breast
cancer, as compared to conventional tests.
“Even when tumors are defined as ‘HER2-positive’, clinical responses to
HER2-target therapies are varied, but it hasn’t been clear what accounts
for the observed differences in outcome,” said Michael Bates, M.D.
Monogram Vice President of Clinical Research. “Taken together, our
studies demonstrate the promise of the VeraTag technology to further
differentiate those tumors likely to respond to HER2-targeted therapies
and aid in the development of personalized treatment strategies for
patients with breast cancer.”
The three studies presented at ASCO are:
Quantitative measure of HER3 total protein (H3T) and association with
clinical outcomes in HER2 positive metastatic breast cancer patients
treated with trastuzumab (abstract #1021):
Study results showed for the first time that adding a quantitative
measure of HER3 protein level results in improved stratification of
outcomes in patients treated with trastuzumab. Researchers analyzed 81
formalin-fixed tissue embedded tumor samples and sub-divided the
patients into HER2 normal and HER2-overexpressing subgroups. The median
time to progression (TTP) in the HER2 normal group was 4.1 months
whereas the HER2 overexpression patient group has a TTP of 11.1 months
(p=0.0002). In this HER2 overexpressing group, high HER3 expression
predicted shorter median TTP (6.1 months) compared with low HER3
expression where the median TTP was 13.1 months (p=0.002). The
presentation also described enhancements to the performance of the HER3
total protein measure by increasing the sensitivity of the test down to
1,000 receptors per cell and the dynamic range of the assay by 30 fold.
Identification of a sub-population of metastatic breast cancer
patients with very high HER2 expression levels and possible resistance
to trastuzumab (abstract #1059):
Recent findings demonstrate that a precise and quantitative measure of
HER2 protein levels allows for the identification of multiple
sub-populations of HER2 positive patients that exhibit different
clinical outcomes on trastuzumab. Using the HERmark breast cancer assay,
a quantitative measure of HER2 total protein expression was assessed in
primary breast tumor specimens from 99 women treated with trastuzumab
for their metastatic disease who were also tested for HER2 by FISH.
Using sub-population treatment effect pattern plot (STEPP) analysis, a
progression free survival (PFS) rate was generated at 12 months after
treatment with trastuzumab.
