Prostate Cancer Diagnosis
Prostate cancer is the most frequent cancer in men, with an estimated 242,000 new cases diagnosed for 2010 in the United States and Canada. The current standard screening method is carried out by measuring the level of prostate specific antigen (PSA) in the blood, combined with a digital rectal examination. An estimated 45 million PSA tests are carried out each year worldwide. However, the sensitivity of the PSA test is being seriously questioned by the scientific community, and its specificity of 27% requires significant improvement. This low specificity results in a high number of false positives, which generate numerous unnecessary and expensive biopsies.
The earlier prostate cancer is detected (i.e. when confined to the prostate gland), the greater are the chances of successful treatment. According to the American Cancer Society, ninety percent of all prostate cancers are found while they are still within the prostate itself or only in nearby areas, and the five-year relative survival rate for these men is nearly 100%. Being diagnosed with prostate cancer may represent a life-altering experience. A clear and in-depth knowledge of the patient’s condition and treatment options should help them make personal and individualized decisions.
PCA3 Test - Summary
“Men with elevated serum prostate-specific antigen (PSA) levels and negative prostate biopsy findings present a dilemma because of the lack of an accurate diagnostic test,” said Leonard S. Marks, MD, clinical associate professor of urology at UCLA and medical director of the Urological Sciences Research Foundation, who was the lead author of a study published in the journal of UROLOGY ® (69: 532-535, 2007). “The results from this research study indicate that the PCA3 assay may be a new tool to assist clinicians in the treatment of these ‘PSA dilemma’ patients.”
In 2000, recognizing the existence of unmet clinical needs for prostate cancer, DiagnoCure acquired from Nijmegen University (The Netherlands) an exclusive worldwide license for all diagnostic and therapeutic applications related to PCA3, a genetic marker highly specific to prostate cancer. DiagnoCure subsequently developed a first diagnostic application, called uPM3™, which enabled the detection of PCA3 RNA expression in prostate cancer cells found in urine.
In 2003, the Company signed a license and collaboration agreement with Gen-Probe Incorporated (NASDAQ: GPRO) for the development and commercialization of a second generation of the PCA3 test on Gen-Probe’s proprietary platform. Since 2005, the performance of Gen-Probe’s PCA3 research test has been validated at internationally respected institutions and presented at numerous American and European scientific meetings. The test, developed in a quantitative format, has a proven analytical sensitivity superior to the original qualitative format of uPM3™.
To date, more than 50 peer-reviewed publications supporting the clinical utility of PCA3 have been released, and others are in the works. In an article published in the British Journal of Urology International (2009; 103:441‐445), which reviewed many PCA3 studies, the authors suggest that PCA3 could be used to increase the confidence in deciding about an initial biopsy as well as a repeat biopsy, and when the biopsy is positive, to assess the aggressiveness of the cancer in order to better weigh the risks and benefits of radical prostatectomy versus active monitoring.
In particular, recent key studies have confirmed the clinical utility of PCA3, which is now moving at the forefront of prostate cancer management.
- In early March 2010, the clinical utility of PCA3 was confirmed in two large worldwide studies, conducted in a subset of about 2,400 patients from GlaxoSmithKline’s REDUCE trial of dutasteride. The studies were presented at the American Society of Clinical Oncology’s Genitourinary Cancers Symposium (ASCO GU) in San Francisco. The results demonstrated that PCA3 can help determine whether men suspected of having prostate cancer should undergo a repeat biopsy and can predict the risk of having an aggressive cancer.
- In April 2010, at the European Association of Urology (EAU) meeting, Pr.Alexandre de la Taille from the urology service of Henri Mondor hospital, Creteil, France, presented the results of a new European study of 516 men. The study suggested that PCA3 could be useful for predicting the outcome of an initial prostate biopsy, thereby reducing prostate biopsies by 40%, while missing only 5% of the high grade cancers on the initial diagnosis. This study represents a significant step forward for PCA3, which up to now, was considered and studied mostly for men undergoing a repeat biopsy.
The PCA3 test is now available through laboratories in the U.S. and Canada using PCA3 analyte specific reagents (ASR) from Gen-Probe as well as in Europe as the CE-marked PROGENSA® PCA3 in vitro assay. In addition the test is being introduced in Japan and Australia through distributors.
Gen-Probe completed in April 2010 a 500-patient clinical trial aimed at securing FDA approval for its PROGENSA® PCA3 test and submitted a PMA in September 2010. PROGENSA® PCA3 was approved by the FDA on February 15, 2012.
Specificity for a cut-off of 4.0ng/ml.
The role of complexed PSA and percent free PSA in prostate cancer detection, Prostate Update, The Canadian Prostate Health Council. S. Tanguay. August 2000, vol. 5, No 1.