Agendia said this week that it has licensed exclusive rights to a genetic profile predicting resistance to tamoxifen from Erasmus MC University Medical Center in Rotterdam, the Netherlands.
Agendia said it plans to offer testing with the profile as part of its MammaPrint breast-cancer prognosis test.
The company hopes clinicians will use the assay to test breast cancer patient tumor samples to determine whether tamoxifen is likely to prove to be an effective treatment, Rene Bernards, Agendia's CSO, told Pharmacogenomics Reporter. The assay could help direct patients toward treatments that might be more effective, such as the new aromatase inhibitors, he said.
Agendia will validate the tamoxifen profile in collaboration with the Netherlands Cancer Institute.
After validation, Agendia hopes to transfer the microarray-based test to a chip containing the 80 or so genes in the test, Bernards said. The company plans to offer the test first in the European Union, and it will discuss with the US Food and Drug Administration how best to provide it in the United States, he said.
None of the genes in the profile is known to be mechanistically related to a pathway of tamoxifen resistance, said Bernards. The genes were instead chosen due to a statistical correlation with resistance during Agendia's testing.
One potential downside of the test in the United States is that it relies on fresh, frozen tissue rather than formalin-fixed paraffin-embedded tissue, which is the most common technique for tissue storage on this side of the Atlantic. Tissue storage in the Netherlands generally depends on fresh-frozen tissue.
The profile is a new twist on what has been a growing emphasis on guiding breast cancer adjuvant therapy with tamoxifen using genomic information. In December, researchers with the Pharmacogenomics Research Network published results in the Journal of Clinical Oncology showing that adding CYP450 testing to current protocols may help clinicians guide treatment with the former AstraZeneca drug, which is now generic. Earlier research by the same group in the Jan. 5, 2005 issue of the Journal of the National Cancer Institute found lower plasma levels of tamoxifen and its metabolites in patients having certain CYP450 2D6 alleles.
In an October meeting, the US Food and Drug Administration will consider relabeling tamoxifen to reflect the utility of patient genomic profiles in guiding treatment with the drug, an anonymous source told Pharmacogenomics Reporter last month. An FDA spokesperson said the agency does not discuss meetings before they have been publicly announced, and a spokesperson for AstraZeneca, the manufacturer of the original, non-generic tamoxifen, said the company had no information about relabeling.