NEW YORK (GenomeWeb) – About a year after launching a new version of its Decipher test for prostate cancer biopsy samples, GenomeDx is seeing encouraging adoption rates, the company said this week after publishing a new study supporting the prognostic power of its test.
Though he did not provide details on the firm's test volume, GenomeDx CEO Doug Dolginow said in an interview this week that while the company is up against competitors in the biopsy space, it is confident that the market is far from saturated, not only for biopsy-based testing, but also in the postsurgical space, where it also offers an assay.
"We've estimated that there are … over 120 different clinical decisions you have to make in managing prostate cancer," he said. "If you look across the biopsy and post-op tissue removed currently, only 6 to 7 percent is genomically assessed by any method," he said.
"We believe that prostate is not much different than breast, where more like 100 percent of samples are tested with some sort of genomic [assay], so over the next five years or so, there is going to be much more extensive assessment of prostate tissue for all patients that have it removed," he added.
The company's study, which appeared online last week in Prostate Cancer and Prostatic Diseases, is the first to show that the company's biopsy assay can predict development of metastasis after men receive standard radiation and androgen deprivation therapy (ADT).
"This is a very complicated decision point for men — when they have a biopsy and it comes back intermediate or high risk," Dolginow said.
The biopsy version of Decipher is intended to divide patients into high- versus low-risk categories. Low-risk patients may be suitable candidates for active surveillance, or may have excellent outcomes when treated with local therapy alone, the company explained.
High-risk patients may benefit from intensification with multimodal therapy.
In the study published last week, academic collaborators at Dana-Farber/Brigham and Women’s Cancer Center, Harvard Medical School, and the Univesity of California, San Francisco showed with researchers from GenomeDx that Decipher Biopsy can accurately identify men who are at an elevated risk of metastatic progression after first-line radiation and hormonal treatment.
Radiation and ADT are a standard first-line treatment for patients diagnosed with intermediate- and high-risk prostate cancer, Dolginow said.
Although this therapy is curative for many men, there remain others whose cancer will at some point go on to progress. Picking these men out has become an attractive target for diagnostic development efforts by several companies, because it offers the opportunity to guide practice so that men at a low risk can avoid unnecessary treatment, while those at a high risk can receive intensified therapy or other interventions that might reduce their mortality.
The analysis included a cohort of 100 men with intermediate- and high-risk prostate cancer who received radiation treatment plus a median of six months of ADT between 2001 and 2013, and who had prostate biopsy samples available from the Dana-Farber/Brigham and Women’s Cancer Center.
Investigators analyzed samples using Decipher Biopsy, alongside standard clinical risk assessment using tools like the National Comprehensive Cancer Network (NCCN) and Cancer of the Prostate Risk Assessment (CAPRA) categorizations.
When the team looked at the clinical versus genomic risk assessments, they found that Decipher Biopsy outperformed clinical variables.
The test accurately predicted the five-year and 10-year risk of distant metastasis with c-indices of 0.76 and 0.78, respectively, the authors reported.
Elai Davicioni, GenomeDx's president and chief scientific officer, said that a particularly important aspect of the findings speaks to the potential of genomic tests like Decipher to help identify men who might need more treatment than standard regimes provide.
In the 26 percent of the study cohort that Decipher testing deemed high-risk (a score greater than 60), 20 percent metastasized within five years.
"From a patient standpoint, if you are in the high genomic risk group, standard of care in this population would be radiation and a short course of hormones. But our results suggest that that may be insufficient. These are people that we are undertreating," he said.
"A lot of attention has been paid to overtreatment of prostate cancer, but it's still the No. 1 killer of men from a cancer perspective in the US and other developed countries. With changes in the amount of screening being done, and as men live longer, there are documented increased rates of metastasis, so it's just not true anymore that men are not going to die of metastasis, as we used to say," Davicioni said.
"There are going to be more men that are actually undertreated, especially in the Medicare population," he added. "So, if you can intensify treatment up front based on elevated risk, you can potentially avoid this instead of trying to salvage patients after the fact."
Before it launched the biopsy version of Decipher, GenomeDx had already been offering a Decipher test designed to predict risk based on an analysis of tissue from men whose prostates had been surgically removed.
With the newer biopsy test, the firm put itself in competition with two other major diagnostic developers, Genomic Health and Myriad Genetics.
So far, the field has yet to see a head-to-head comparison of any of these tests, and as such, clinicians lack a sense of which may be the best to use.
According to Dolginow, GenomeDx welcomes such a comparison, but isn't spearheading any head-to-head studies itself.
Guidelines released by the National Comprehensive Cancer Network include specific mentions of Myriad's Prolaris and Genomic Health's Oncotype DX for biopsies, and Decipher for post-prostatectomy samples, but not yet for the biopsy version of GenomeDx's test.
National Medicare benefit administration contractor Palmetto GBA issued a positive local coverage decision for Decipher in the post-op space in early 2015. It also finalized local coverage determinations for Myriad's Prolaris and for Oncotype DX Prostate.
Most recently, at the end of December, Palmetto released a draft LCDÂ proposing to extend coverage for Prolaris to patients at intermediate risk for prostate cancer in addition to low-risk individuals.
According to GenomeDx, Decipher Biopsy is intended for use in patients who present with the full range of clinical results — from very low through high risk — but Palmetto has not yet released a draft or final LCD for the biopsy version of the test.
Although Dolginow expressed confidence about the uptake of Decipher, some physicians may remain skeptical about whether the added value of genomic tests over other clinical measures merits their price tag. Â
For example, despite studies published by GenomeDx and its competitors highlighting how frequently or substantially the tests change physician decision making, Urological Research Foundation director William Catalona said last year that in his personal experience, it was still a rare case where information from a molecular test changes what he would have recommended to a patient anyway.
Evidence such as the kind included in GenomeDx's more recent study should help change that, Dolginow argued.
"At baseline, if you look at what clinicians typically use for clinical risk assessment, it's primarily Gleason score with things like age and PSA and general health playing a role, too," he said.
"But 50 percent of the time, Gleason changes if a patient goes from biopsy to prostatectomy, and it varies not only from physician to physician but even with the same physician [doing multiple assessments]," he added.
"Based on our results, the genomic predictor is significantly more prognostic — and potentially predictive — than the clinical parameters traditionally have been, and that's not surprising, considering the data we have showing genomic targets we are using in Decipher are independent of clinical parameters," he said..
According to Dolginow, GenomeDx has a "significant market share."
"Less than 10 percent [of patients with tissue available] are evaluated right now, so we are in a growing market for everyone, and we feel like our current adoption is faster than the overall market growth," he added.
While the company has not yet provided any details about how much testing it is doing in the biopsy space compared to the post-prostatectomy setting, Dolginow said that the market for biopsy is much larger – about five times bigger in the US, with approximately 200,000 men a year being diagnosed.