Genomic Health, Inc. (Nasdaq: GHDX) today announced the presentation of two studies at the American Society of Clinical Oncology® (ASCO®) Genitourinary (GU) Cancer Symposium, including complete results from its prostate cancer gene identification study, which identified 295 genes strongly associated with clinical recurrence following radical prostatectomy with great consistency across multiple tumor samples examined in each patient. Additionally, the company announced that a separate analysis from the gene identification study, which will be presented at the United States & Canadian Academy of Pathology (USCAP) 2011 meeting, suggests that prostate cancer gene expression adds prognostic information beyond clinical and pathological criteria. All of the analyses apply the same reverse transcriptase-polymerase chain reaction (RT-PCR) technology used in Genomic Health's Oncotype DX® breast and colon cancer tests.
"Based on these additional analyses presented by Cleveland Clinic researchers at ASCO-GU and USCAP we expect that, once validated in a well designed clinical trial, individualized gene expression will be incorporated into clinical practice along with traditional measures to aid physicians and patients in making critical treatment decisions regarding active surveillance and immediate prostatectomy or radiation therapy, or the need for adjuvant therapy after initial treatment,” said Steven Shak, chief medical officer at Genomic Health. "Answering these important questions will require multiple clinical studies with reproducible evidence including the ability to work with very small amounts of biopsy tissue, areas where we believe Genomic Health has established unique expertise over the past decade through our successful work across multiple cancers. We look forward to finalizing analytical methods this year to support a clinical validation study in prostate cancer next year.”
Complete Results from Prostate Gene Identification Study
"The consistency observed in this study across multiple tumor samples examined in each patient as well as consistency across multiple clinically important endpoints, including clinical recurrence, upstaging or upgrading, biochemical recurrence and prostate cancer specific survival, is very encouraging," said Eric Klein, M.D., Chairman of the Glickman Urological and Kidney Institute at Cleveland Clinic. "Results from these analyses suggest that gene expression profiling in prostate cancer may be useful in deciding on treatment verses active surveillance, or the need for adjuvant therapy after prostatectomy."
Researchers analyzed RNA from 431 prostate cancers among patients treated with radical prostatectomy (RP) at Cleveland Clinic between 1987 and 2004. Of the 732 cancer-related and six reference genes assessed, 295 were significantly predictive (unadjusted p<0.05) of clinical recurrence-free interval (cRFI) using Cox PH regression. The number of genes predicting clinical recurrence was well in excess of that expected by chance alone. In addition, because prostate cancer often shows heterogeneity when viewed by microscopic examination, researchers tested two samples of prostate cancer in each patient. New data showed a highly consistent relationship of gene expression to clinical recurrence in both the primary, or most common, and the highest Gleason pattern samples. These results indicate that there is an underlying biology that can be revealed with quantitative RT-PCR that overcomes the apparent heterogeneity that is visible by microscopic examination. The study, "Use of quantitative gene expression in primary and highest Gleason pattern cancers to identify genes associated with clinical recurrence after radical prostatectomy " (Klein et al, Abstract #39), will be presented in a poster session on Thursday, February 17.
Additionally, since prior studies from other groups have had mixed results, researchers conducted a separate analysis on the RNA to determine if an association exists between prostate cancer DNA alterations that have been recently discovered (gene rearrangements called TMPRSS2-ERG fusions) and adverse clinical outcomes. Results from this study indicated that there is no association of expression of TMPRSS2-ERG fusions or ERG expression with aggressiveness of prostate cancer after radical prostatectomy. Specifically, researchers did not find an association of TMPRSS2-ERG gene rearrangements or ERG expression with clinical recurrence, PSA recurrence, or PCA-specific survival in either primary or highest Gleason pattern tumor samples. The study, "Use of TMPRSS2-ERG gene rearrangement and quantitative ERG expression to predict clinical recurrence after radical prostatectomy" (Klein et al, Abstract #36), will be presented in a poster session on Thursday, February 17.
Quantitative Gene Expression Using RT-PCR Adds Prognostic Information Beyond Clinical and Pathological Criteria
A separate analysis utilizing the same RNA as the studies presented at ASCO-GU will be presented at the USCAP 2011 meeting in San Antonio, Texas and suggests that prostate cancer gene expression adds prognostic information beyond clinical and pathological criteria such as prostate-specific antigen (PSA), The American Urological Association (AUA) criteria and Cancer of the Prostate Risk Assessment (CAPRA) Score. The analysis showed that many genes were significantly (unadj. p<0.05) associated with clinical recurrence, PSA recurrence, and PCSS (295, 235, and 203 genes respectively). Additionally, many genes remained significantly associated with each of the outcomes in multivariate analyses adjusting for pathologic T-stage, tumor specimen Gleason pattern (GP), Gleason score (GS), AUA group and CAPRA score. For the strongest 20 genes, the magnitude of association was diminished by less than 20 percent after adjustment for stage, GP, AUA, and CAPRA, and less than 50 percent after adjustment for GS. The study, "Prostate Cancer Gene Expression Adds Prognostic Information beyond Clinical and Pathological Criteria Such as Stage, Gleason Score, PSA, AUA Criteria, and CAPRA Score " (Falzarano et al, Abstract #803), will be presented in an oral session on Monday, February 28 at 1:45 p.m. CT.
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