Genomic Health Publishes Development, Validation Studies on Oncotype DX Prostate Cancer Dx
Genomic Health has published in European Urology data from three studies involving its 17-gene Oncotype DX prostate cancer test.
The study, entitled "A 17-gene Assay to Predict Prostate Cancer Aggressiveness in the Context of Gleason Grade Heterogeneity, Tumor Multifocality, and Biopsy Undersampling," showed that the 17-gene Oncotype DX prostate score is a significant predictor of disease aggressiveness at the time a man is diagnosed with the disease. Researchers led by Cleveland Clinic’s Eric Klein further reported that Oncotype DX provides more accurate prognostic assessments than clinical and pathological risk factors for prostate cancer patients.
Genomic Health developed its test with researchers from Cleveland Clinic and University of California, San Francisco. Among the studies reported in the paper include two development trials conducted with the Cleveland Clinic – one analyzing close to 450 prostatectomy samples and another analyzing 167 small needle biopsy specimens. These studies enabled Genomic Health to narrow down the panel of genes from 700 candidate markers to 17 genes that address four key biological pathways involved in prostate cancer.
The third clinical validation study, which Genomic Health conducted with UCSF, involved biopsy samples from 395 men who were candidates for active surveillance. The Oncotype DX prostate cancer test was able to determine which patients were at high risk of prostate cancer and held up to be a significant prognostic tool in multivariate analysis against standard clinical measures. Additionally, when the Oncotype DX score was paired with National Comprehensive Cancer Network categories or gold standard CAPRA scores, researchers reported a significant improvement in risk assessments and an increase in the number of patients who would do well with active surveillance.
"In our validation study, Oncotype DX significantly increased the number of patients who can more confidently consider active surveillance,” Peter Carroll, a study investigator from UCSF, said in a statement announcing the publication of the trial results. “Importantly, the [Oncotype DX score] also identified a subset of patients who, despite seemingly low-risk clinical factors, had more aggressive disease, suggesting that they may want to consider immediate treatment and/or additional evaluation."
At the end of last year, Genomic Health and Cleveland Clinic researchers published data in BMC Genomics on the prostate cancer test’s analytical validation. Genomic Health launched its Oncotype DX prostate cancer test in 2013. The test analyzes the expression of 17 genes to gauge prostate cancer aggressiveness, reporting a score from 0 to 100. A lower score indicates that a patient might be able to avoid treatment in favor of continued active surveillance.
During a recent earnings call, Genomic Health officials reported that so far more than 675 physicians have ordered its prostate cancer test and more than half of these doctors have used the test on multiple patients. Genomic Health is touting its test as a tool that doctors can use primarily to identify low risk or intermediate risk patients – the most appropriate candidates for active surveillance.
The company estimates there are 140,000 prostate cancer patients each year in the US who fall in this risk category and are potentially over treated, putting the US market opportunity of the Oncotype DX prostate cancer test at $450 million. The company to date has completed 10 studies on this test.
MDxHealth Publishes Clinical Utility Study on Prostate Cancer Test
Researchers from MDxHealth and other institutions published a clinical utility study involving the ConfirmMDx prostate cancer test in American Health & Drug Benefits. Researchers led by Kirk Wojno from Comprehensive Urology reported that the use of ConfirmMDx reduced repeat biopsies by 10-fold in patients with negative epigenetic test results compared to those treated according to standard histopathological measures.
The study involved 138 patients at five urology practices who had had cancer negative biopsies over a period of 18 months and researchers analyzed these patients using MDxHealth’s test. Based on the results of ConfirmMDx, doctors performed repeat biopsies on six of the 138 men, or on less than 5 percent of patients, who had a negative epigenetic test result. No evidence of prostate cancer was found in the men on who repeat biopsies were performed.
“The data suggest that patients managed using the ConfirmMDx for Prostate Cancer negative results had a low rate of repeat prostate biopsies, Wojno and colleagues concluded. “These results warrant a large, controlled, prospective study to further evaluate the clinical utility of the epigenetic test to lower the unnecessary repeat biopsy rate.”
The ConfirmMDx prostate cancer test uses methylation-specific PCR to determine the epigenetic status of genes associated with prostate cancer – GSTP1, APC, and RASSF1. Earlier, MDxHealth published a validation study, called DOCUMENT, on the prostate cancer diagnostic. The study showed the test to be a significant, independent predictor of the risk of occult cancer compared to standard risk assessment factors and suggested that the test can help physicians decide whether or not to perform a repeat biopsy on a patient.
MDxHealth estimates that 975,000 men in the US receive a negative biopsy result each year, but since 25 percent may still harbor occult cancer, more than 40 percent of these men receive at least one repeat biopsy. Although prostate biopsies are a gold standard diagnostic measure, the procedure is imprecise, only sampling 1 percent of a man’s prostate.
The company is currently focused increasing adoption of its prostate cancer test. In 2013, approximately 7,000 patients were tested, compared to just over 1,000 patients in 2012. Last year, the company also inked 10 coverage agreements with a number of payors for the test
GenomeDx Presents Abstracts on Decipher Prostate Cancer Dx at AUA
GenomeDx Biosciences presented data this week at the American Urological Association’s annual meeting that its Decipher Prostate Cancer Classifier can accurately identify which patients after prostate surgery are at low risk of metastasis and therefore may be spared radiation therapy.
In a second study poster presented at the meeting, the company reported that the genomic test outperformed standard clinical tools in being able to predict treatment failure in patients after prostate surgery.
In the first study, by Magi-Galluzzi, et al., researchers tested with Decipher samples from 183 patients who had been conservatively managed after prostate surgery from 1987 to 2008 at the Cleveland Clinic. “Decipher had an area under the curve of 0.78 for predicting distant metastasis in patients who had not been treated after prostatectomy with adjuvant therapy,” GenomeDx said in a statement. Multivariate analysis showed that Decipher was the “predominant predictor” of distant metastasis. After adjusting for clinical risk factors, the data showed that patients deemed to be high risk by the test were five times more likely to advance to metastatic disease compared to low risk patients.
In the second abstract, by Trabulsi et al., researchers analyzed with Decipher samples from patients in two cohorts treated with radiation after surgery. In the first cohort of 139 men, biochemical recurrence six years after radiation therapy was 21 percent for those with a low Decipher score, 40 percent for those with an intermediate score, and 63 percent for those with a high score. In the second cohort, clinical metastasis six years after radiation treatment was 6.5 percent in low scoring patients, 15 percent in intermediate patients, and 38 percent for high risk patients.
GenomeDx estimated that nine out of 10 men with prostate cancer considered at high risk for metastasis after surgery by standard clinical and pathological measures will not experience progression or die from the disease. However, according to current clinical guidelines all high-risk patients should be offered secondary radiation treatment to reduce their chances of metastasis, the firm noted in a statement reporting on the study results.