A multi-center study confirming the prognostic value of Oncotype DX in Japanese breast cancer patients will likely boost Genomic Health's marketing efforts and help drive adoption of the test in the country.
Researchers from the Japan Breast Cancer Research Group presented results at the Kyoto Breast Cancer Consensus Conference earlier this month demonstrating that Oncotype DX had "significant prognostic value" in identifying the risk of cancer recurrence in Japanese women with estrogen receptor-positive early-stage breast cancer. The company said that the results were consistent with clinical studies conducted in the US and Europe.
In this population of Japanese women, the Oncotype DX recurrence score "identified a large proportion of patients with very low risks of distant recurrence," concluded a team of researchers led by Masakazu Toi, director of the Japan Breast Cancer Research Group and a professor in the Department of Surgery at Kyoto University School of Medicine.
Based on these results, lead author Toi said in a statement that "Oncotype DX should be integrated into standard breast cancer treatment planning for patients in Japan."
Even though Japanese regulatory authorities have in the past approved the use of chemotherapy agents that have not been studied specifically in Japanese populations, Genomic Health said it carried out the confirmatory study in an effort to increase doctors' confidence in Oncotype DX.
"While Japanese physicians were quite willing to use Oncotype DX in their patients without specific Japanese data, they said they would be more comfortable if the test was shown to work in Japanese patients," a Genomic Health spokesperson told Pharmacogenomics Reporter this week.
Genomic Health previously said that this year it plans to grow its “presence and investments” for Oncotype DX in Asia, Europe, South America, and Canada [see PGx Reporter 05-14-2008].
The company spokesperson acknowledged that Genomic Health considers Japan to be a "major market" for Oncotype DX, but she did not provide details of the projected market for that region. SRL, the exclusive distributor of Oncotype DX in Japan, has been marketing the diagnostic in the region since 2007.
In the study, conducted by Toi et al., researchers evaluated tumor samples from 200 patients with early-stage, ER-positive, lymph node-negative breast cancer who were treated with tamoxifen, and who had surgery between 1992 and 1998. The tissue samples were then analyzed based on the standard algorithm involving the expression of 21 genes and patients were given a recurrence score. Using this score yielded from the Oncotype DX test, patients were categorized into the low- (less than 18 points), intermediate- (between 18 points and 30 points), or high- risk (more than or equal to 31 points) groups.
Of the Japanese patients participating in the study, 48 percent had a recurrence score less than 18; 20 percent had a recurrence score between 18 and 30; and 33 percent had a recurrence score greater than or equal to 31. Of those with a recurrence score less than 18, 3 percent had disease recurrence at 10 years, while 25 percent of patients with a recurrence store greater than or equal to 31 had disease recurrence at 10 years.
"The distribution of recurrence scores in the Japanese population was similar to that found in previous multi-center studies performed in the US," the study authors state in the abstract. "A large proportion of breast cancer patients in Japan were identified by the recurrence score to have a low likelihood of distant recurrence when treated with tamoxifen alone without chemotherapy." The study did not address prediction of chemotherapy benefit since all patients were only treated with tamoxifen.
The results of this study are not yet published. "The study will be sent for publication but journal and timing are pending," the Genomic Health spokesperson said without elaborating.
Including Japan, Genomic Health is currently receiving samples from more than 40 countries, but has not yet broken out international sales figures for Oncotype DX, noting that sales figures are still "modest" outside the US. However, according to company officials, the strongest adoption rates for Oncotype DX are in those countries where the test has the support of payors.
In Japan, personal medical services are paid through a universal healthcare insurance system, in which self-employed people, students, and those without insurance are covered by their local governments, and corporate employees are covered by their employers.
Meanwhile, the company does not expect to conduct confirmatory trials of this kind for too many other territories, though it is planning such a study for Taiwan. "The great majority of thought leaders outside the US do not seem to require confirmation as [Oncotype DX] has been studied in over 4,000 patients," the Genomic Health spokesperson noted.
Other than Oncotype DX, a variety of gene-based breast cancer tests predict cancer recurrence, including products made by Agendia and Exagen. Agendia's MammaPrint assay, both CE-marked in Europe and cleared by the US Food and Drug administration, is perhaps Genomic Health's main competitor in this market. Exagen filed its eXagenBC test for 510(k) clearance with the FDA in 2007.