Top-line results from a study involving Genomic Health's investigational colorectal cancer assay validated the test's prognostic ability to determine the likelihood of disease recurrence, but not its predictive ability to gauge treatment benefit.
Genomic Health this week announced that the landmark QUASAR validation study met its primary endpoint to predict the likelihood of post-operative disease recurrence in patients with stage II colon cancer. However, the test did not meet a second endpoint using a set of genes to predict which patients are likely to benefit with post-operative 5-fluorouracil/leucovorin treatment.
Genomic Health will not provide full results or interpretation of the data until the study is peer-reviewed and published at the upcoming annual meeting of the Association of Clinical Oncology. Following the meeting, which will take place from May 29 to June 2 in Orlando, the company will provide additional details, including its commercialization strategy for the test, company officials said.
As part of the research, the company completed four developmental studies evaluating more than 760 candidate genes in 1,800 patients to elect the gene panel for the assay. The resulting genes, comprising two separate scores — one for disease recurrence and one for treatment response — were then evaluated using more than 1,200 colon cancer tumor specimens from the QUASAR study.
The colon cancer assay, which stands to be the firm's second commercialized test, will be based on Genomic Health's Oncotype DX platform. Since 2004, the company has been marketing a breast cancer test by the same name that gauges both disease recurrence and chemotherapy benefit based on a panel of 21 genes.
"Now that we have this positive result, we will now move foreword with the work required to make the Oncotype DX colon cancer assay available to physicians and patients in early 2010," Genomic Health CEO Kim Popovits told investors during a conference call to announce the results from the validation study.
Ahead of that launch, Genomic Health will need to ensure that its CLIA lab will have the capacity to process the additional samples.
Although Genomic Health markets its Oncotype DX breast cancer test through its CLIA lab, the US Food and Drug Administration has been in discussion with the company about submitting the test for regulatory approval.
Since the Oncotype DX platform issues a recurrence score based on a panel of genes, it will likely be considered a complex test that falls under the FDA's in vitro diagnostic multivariate index assay guidelines.
Although, the agency has yet to make a definitive decision on the regulatory status of the Oncotype DX platform, and the final IVDMIA guidance has been pending for several years, any regulatory changes in this regard before 2010 could torch the company's plans to launch the colorectal cancer assay through the CLIA pathway [see PGx Reporter 04-08-2009].
Popovits acknowledged the possibility that regulatory changes could alter the company's launch plans for the test, but said the launch timelines could not be expedited since "complex" clinical issues still had to be ironed out.
"What's important to us, despite what's happened in the regulatory environment, is that we do the necessary things as we did with the breast cancer assay," Popovits said. "Unlike a traditional diagnostic product, [the colorectal cancer] involves some complicated things regarding our information systems and our commercial strategy around it."
If the FDA issues the final IVDMIA guidance before Genomic Health is ready to launch the colorectal cancer test, "then we feel we'll be in good shape to follow [the IVDMIA] path," Popovits said. However, "we have no information to date to suggest that any path other than CLIA would be the right way to take this through."
The company announced the clinical trial results on April 14 after markets closed. The following afternoon, Genomic Health's shares were down 13 percent to $21.95.