The first study has demonstrated a high degree of overall concordance – 95% – between central immunohistochemistry (IHC) and quantitative RT-PCR using Oncotype DX for determining HER2 status. The study analyzed 755 patients with zero to three positive lymph nodes who were enrolled in Intergroup study E2197, a large adjuvant breast cancer trial evaluating two different chemotherapy regimens.
The second study found a high degree of concordance – 97% – between RT-PCR using Oncotype DX and central laboratory fluorescence in situ hybridization (FISH) assessment of HER2 status. The study was conducted by Genomic Health and collaborators from Kaiser Permanente, the University of California, San Francisco, and PhenoPath.
HER2 measurement was assessed by central FISH and quantitative RT-PCR using Oncotype DX in 568 patients from a large Kaiser Permanente case-control study.
The company expects to further increase the clinical utility of its test by including single gene reporting for quantitative HER2 gene expression in all Oncotype DX reports by the end of 2008.
Steven Shak, chief medical officer of Genomic Health, said: “Based on this research demonstrating the accuracy and reliability of HER2 measurement using RT-PCR, Oncotype DX can provide additional patient-specific information and insight into each patient’s individual tumor biology.”