- Eight Studies Presented at Leading Urology Meeting Show that Simple Urine Test for PCA3 Gene May Improve Accuracy of Prostate Cancer Detection, Reduce Unnecessary Biopsies -

- Gen-Probe to Begin Pivotal Clinical Study in Effort to Gain U.S. Regulatory Approval -

SAN DIEGO, April 29 /PRNewswire-FirstCall/ -- Eight studies presented this week at the annual meeting of the American Urological Association (AUA) suggest that Gen-Probe's (Nasdaq: GPRO) investigational test for the highly specific prostate cancer gene PCA3 may help address some of the well-known challenges that urologists face when diagnosing prostate cancer, such as accurately identifying potentially aggressive cancers while minimizing "false positive" results that can lead to overtreatment.

In response to these studies and other promising data from approximately 17 peer-reviewed publications, Gen-Probe has decided to initiate a pivotal clinical study of its investigational PCA3 assay that could lead to regulatory approval by the U.S. Food and Drug Administration (FDA).

"Based on the results of our extensive clinical research studies and our European commercial experience, we believe that our PCA3 assay, when used in conjunction with other tests, can help predict the risk of a positive follow-up biopsy, thereby aiding in the diagnosis of prostate cancer," said Henry L. Nordhoff, Gen-Probe's chairman and chief executive officer. "We are pleased to be moving ahead with a U.S. clinical trial that could lead to improved patient care."

Gen-Probe's clinical study is expected to begin in the third quarter of 2009 and take about a year to complete. The Company anticipates it will involve more than 500 men, all of whom have had a negative prostate biopsy, at 10 or more clinical trial sites.

Scientific studies presented in recent weeks have added to the uncertainties surrounding prostate cancer screening and diagnosis. For example, researchers from the U.S. National Cancer Institute recently published results in the New England Journal of Medicine (NEJM) from a 17-year study that showed that six annual screenings for prostate cancer led to more diagnoses of the disease, but no fewer prostate cancer deaths.

"We need better tools to detect significant prostate cancers earlier, to reduce unnecessary biopsies and overtreatment, and to identify which tumors are most likely to progress," said Gerald L. Andriole, MD, lead author of the NEJM paper and professor and chief of urologic surgery at the Washington University School of Medicine in St. Louis. "Early data on the investigational PCA3 genetic test are promising, and we look forward to additional studies to confirm its clinical utility."

Key AUA Studies

Results from selected PCA3 studies presented at the AUA meeting showed that:
-- PCA3 scores are correlated with the probability of a positive initial prostate biopsy in men with elevated serum PSA levels. In addition, PCA3 scores were higher in men whose prostate tumors had higher Gleason scores, which indicate cancer aggressiveness.(1)
-- PCA3 scores correlated with prostate cancer tumor volume, another measure of cancer aggressiveness, but not with the size of the prostate gland itself. In addition, PCA3 scores were higher in men with pathologically significant cancers than in men with insignificant ones.(2)
-- PCA3 scores increased the accuracy of a nomogram that doctors can use to predict which men have low-grade or low-volume prostate cancers.(3) These men may be candidates for active surveillance rather than aggressive treatment. A nomogram is a two-dimensional diagram or graph that is used to calculate the likelihood of a medical outcome.
-- The PCA3 test was used reliably and consistently in a busy, community-based screening setting.(4)

About PCA3

PCA3 is a gene that is highly over-expressed in more than 90% of prostate tumors, indicating that it may be a useful biomarker for prostate cancer. Studies have shown that because PCA3 is highly specific for prostate cancer, it predicts the results of repeat biopsies more accurately than traditional prostate-specific antigen (PSA) testing.(5)

Gen-Probe's PROGENSA(R) PCA3 assay, which has been CE-marked for sale in the European Union, is the first urine-based molecular diagnostic assay for prostate cancer. The test has not been approved for marketing in the United States.

Gen-Probe acquired exclusive worldwide diagnostic rights to the PCA3 gene from DiagnoCure in November of 2003.

About Gen-Probe

Gen-Probe Incorporated is a global leader in the development, manufacture and marketing of rapid, accurate and cost-effective nucleic acid tests (NATs) that are used primarily to diagnose human diseases and screen donated human blood. Gen-Probe has more than 25 years of NAT expertise, and received the 2004 National Medal of Technology, America's highest honor for technological innovation, for developing NAT assays for blood screening. Gen-Probe is headquartered in San Diego and employs approximately 1,200 people. For more information, go to www.gen-probe.com.

Caution Regarding Forward-Looking Statements

Any statements in this press release about Gen-Probe's expectations, beliefs, plans, objectives, assumptions or future events or performance are not historical facts and are forward-looking statements. These statements are often, but not always, made through the use of words or phrases such as believe, will, expect, anticipate, estimate, intend, plan and would. For example, statements concerning new products, potential regulatory approvals, customer adoption, and results of future R&D studies are all forward-looking statements. Forward-looking statements are not guarantees of performance. They involve known and unknown risks, uncertainties and assumptions that may cause actual results, levels of activity, performance or achievements to differ materially from those expressed or implied by any forward-looking statement. Some of the risks, uncertainties and assumptions that could cause actual results to differ materially from estimates or projections contained in the forward-looking statements include but are not limited to: (i) the risk that subsequent studies of our PCA3 assay may not reflect the results discussed here, (ii) the risk that new products, such as our PCA3 assay, will not be cleared for marketing in other markets in the timeframes we expect, if at all, (iii) the possibility that the market for the sale of our new products, such as our PCA3 test, may not develop as expected, (iv) the risk that we may not be able to compete effectively, (v) the risk that we may not be able to maintain our current corporate collaborations and enter into new corporate collaborations or customer contracts, and (vi) our dependence on third parties for the distribution of some of our products. The foregoing describes some, but not all, of the factors that could affect our ability to achieve results described in any forward-looking statements. For additional information about risks and uncertainties Gen-Probe faces and a discussion of the Company's financial statements and footnotes, see documents filed with the SEC, including the most recent annual report on Form 10-K and all subsequent periodic reports. We assume no obligation and expressly disclaim any duty to update any forward-looking statement to reflect events or circumstances after the date of this news release or to reflect the occurrence of subsequent events.

(1) AUA poster #1816, "Can prostate cancer gene 3 (PCA3) predict initial biopsy outcome?" Alexandre de la Taille, et al.
(2) AUA poster #2127, "Prostate cancer antigen 3 (PCA3) shows significant association to prostate cancer volume but no correlation to total prostate volume or serum Prostate Specific Antigen." Felix K h Chun, et al.
(3) AUA poster #155, "PCA3 score-based nomogram to predict low-volume / low-grade prostate cancer in radical prostatectomy specimens." John Ward, et al.
(4) AUA poster #1814, "Feasibility of the PCA3 urine test in a community- based screening setting." Adrie van Bokhoven, et al.
(5) UROLOGY(R) (69:532-535, 2007).

Contact:
Michael Watts
Vice president, investor relations and
corporate communications
858-410-8673

SOURCE Gen-Probe Incorporated
04/29/2009
CONTACT: Michael Watts, Vice president, investor relations and corporate communications of Gen-Probe, +1-858-410-8673/ /Web Site: http://www.gen-probe.com
(GPRO)