Study Demonstrates ViroLogic's eTag System Can Measure Activated VEGF Receptor, Target for Anti-Angiogenic Treatments

Study Demonstrates ViroLogic's eTag System Can Measure Activated
VEGF Receptor, Target for Anti-Angiogenic Treatments
-Abstract #9595- 


ORLANDO, Fla., May 15  /PRNewswire-FirstCall/ -- ViroLogic, Inc., (NASDAQ:VLGC)
announced today the presentation of data demonstrating the ability of the
company's eTag(TM) Assay System to provide a direct measure of activated
Vascular Endothelial Growth Factor (VEGF) receptor type 2 (VEGFR2, also known
as KDR), and its effects on downstream signal transduction pathways in an in
vitro model system.  The presentation took place at the 2005 American Society
of Clinical Oncology (ASCO) Annual Meeting being held this week at the Orange
County Convention Center in Orlando, FL.

Currently, there is no direct method of detecting activated VEGFR2, and an
assay able to measure this, and potentially indicate its contribution to tumor
blood vessel development in individual patients, could aid in the prescription
of anti-angiogenic therapies.  Angiogenesis is the process by which new blood
vessels are generated in the body and are directed to tissues undergoing rapid
growth or in need of additional nutrients.  It is a critical factor in tumor
growth and metastasis because tumor cells divide and grow very rapidly, and
typically secrete angiogenic factors to ensure an adequate blood supply. There
are a number of peptide and protein factors that stimulate angiogenesis and a
key one is VEGF, which acts through the VEGFR2 receptor.  Much effort is being
directed toward blocking VEGF, VEGFR2 and other angiogenic signaling pathways
in different types of cancer with targeted therapeutics such as monoclonal
antibodies like Avastin(R) (bevacizumab), approved for use in colon cancer and
exhibiting clinical activity in studies in lung and breast cancer, as well as
small molecule VEGFR2 kinase inhibitors that are still in development.

"Our data in these cell lysate studies show that the eTag assay gives a direct
measure of the activation of VEGFR2 and the signaling pathway it modulates,"
said Sharat Singh, Ph.D., ViroLogic's Chief Technical Officer, Oncology, and
co-author of the study.  "We are currently utilizing very similar eTag assays
for activated EGFR receptors with human clinical samples. We feel that the
VEGFR2 assay could also be used in this setting, first as a selection tool to
determine whether a VEGF pathway inhibitor, like Avastin, is an appropriate
therapy for a patient, and then potentially to measure modulation of activated
VEGFR2 as a marker for efficacy of certain angiogenesis inhibitors."

"Our work on clinical tumor samples to date with eTag assays has focused on
activated EGFR and HER receptors, which we expect to be the focus of our first
commercial oncology product," said William D. Young, Chairman and CEO of
ViroLogic.  "This early cell lysate work in the VEGF receptor family indicates
the potentially broader reach of our technology, where receptor activation
through protein complex formation is a key feature of the biology."

Researchers at ViroLogic stimulated Human Umbilical Vein Endothelial Cells with
increasing concentrations of VEGF for different periods of time.  The eTag
assays were used to detect VEGFR2 homodimers, VEGFR2 phosphorylation, and
downstream pathway activation in whole cells lysates.  The downstream proteins
assayed in the signal transduction pathway stimulated by VEGF included Erk,
BAD, RSK, and Akt.

The level of VEGFR2 homodimers was found to increase with increasing doses of
VEGF.  Phosphorylation of VEGFR2 was transient, peaking at one minute of VEGF
treatment and falling to background level after five minutes.  One minute
dosing of VEGF showed increasing VEGFR2 phosphorylation with increasing levels
of VEGF.  Downstream pathway proteins Erk, RSK, and BAD were activated with
increasing levels of VEGF.

About the eTag System

ViroLogic's eTag assays enable detailed analysis of protein drug targets and
signaling pathways in cancer cells, including samples that are formalin- fixed,
paraffin-embedded, which is the standard format in most pathology labs. The
assays can provide information on a drug's mechanism of action, selectivity and
potency in a biological setting in pre-clinical research, and enable enrichment
or selection of clinical trial populations later in a drug's development.  In
addition, ViroLogic believes these assays may ultimately be used to help
physicians better determine whether certain therapies are more appropriate for
individual cancer patients, and whether to combine therapies with different
mechanisms or properties.  The first commercially available activated receptor
test panel based on eTag technology, focused on the EGFR/HER receptor family,
is planned to be introduced in 2006.

About ViroLogic

ViroLogic is a biotechnology company advancing individualized medicine by
discovering, developing and marketing innovative products to guide and improve
treatment of serious infectious diseases and cancer.  The Company's products
are designed to help doctors optimize treatment regimens for their patients
that lead to better outcomes and reduced costs.  The Company's technology is
also being used by numerous biopharmaceutical companies to develop new and
improved antiviral therapeutics and vaccines as well as targeted cancer
therapeutics.  More information about the Company and its technology can be
found on its web site at http://www.virologic.com/.

FORWARD-LOOKING STATEMENTS

Certain statements in this press release are forward-looking, including
statements regarding the trend toward individualized medicine and the results
of yet-to-be completed clinical studies related to the effectiveness of our
eTag assays as predictive tools for targeted cancer therapies. These forward-
looking statements are subject to risks and uncertainties and other factors,
which may cause actual results to differ materially from the anticipated
results or other expectations expressed in such forward-looking statements.
These risks and uncertainties include, but are not limited to, risks and
uncertainties relating to the development of future products; the performance
of our products; our ability to successfully conduct clinical studies and the
results obtained from those studies; whether larger confirmatory clinical
studies will confirm the results of initial studies; whether larger studies
involving tumor samples will yield favorable results regarding the predictive
capability of eTag assays for responsiveness to Avastin or other VEGF
inhibitors; our ability to establish reliable, high-volume operations at
commercially reasonable costs; our ability to introduce a product commercially
in 2006; our ability to successfully integrate the operations of ACLARA into
our operations; competition from larger more established diagnostic providers;
actual market acceptance of our products and adoption of our technological
approach and products by pharmaceutical and biotechnology companies; our
estimate of the size of our markets; our estimates of the level of demand for
our products; the timing and ultimate size of pharmaceutical company clinical
trials; whether payors will authorize reimbursement for our products; whether
the FDA or any other agency will seek to regulate ViroLogic's in house clinical
laboratory testing; our ability to comply with FDA regulations in order to
establish and maintain diagnostic kit manufacturing operations; whether we will
encounter problems or delays in establishing and validating eTag assays within
our clinical laboratory; whether we will encounter problems or delays in
automating our processes or expanding our capacity; whether the intellectual
property underlying the Company's technology is adequate; whether we may be
deemed to infringe on the intellectual property of others and whether licenses
to third party technology will be available; whether ViroLogic is able to build
brand loyalty and expand revenues; the potential impact of any payments under
the CVRs on our common stock and capital resources; and whether ViroLogic will
be able to raise sufficient capital when required. For a discussion of other
factors that may cause ViroLogic's actual events to differ from those
projected, please refer to the Company's most recent annual report on Form 10-K
and quarterly reports on Form 10-Q, as well as other subsequent filings with
the Securities and Exchange Commission.  We do not undertake, and specifically
disclaim any obligation, to revise any forward looking statements to reflect
the occurrence of anticipated or unanticipated events or circumstances after
the date of such statements.

eTag is a trademark of ViroLogic, Inc. Avastin(R) is a registered trademark of
Genentech. 

DATASOURCE: ViroLogic, Inc.



CONTACT:  Alfred Merriweather, Vice President and CFO of ViroLogic,

[phone]; or Carolyn Bumgardner Wang of WeissComm Partners,

[phone], , for ViroLogic



Web site:  http://www.virologic.com/ 

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