DirectHit is based on quantitative immunofluorescencetechnology. According to recent studies, quantitative immunofluorescence (QIF) can be applied to the standardization of protein analysis, resulting in increased sensitivity and reproducibility.[6] It is important to be able to quantitate the expression of predictive factors in breast cancer, because response to therapy is often dependent upon the concentration of particular proteins within the tissue.[7][8]
DirectHit utilizes monoclonal antibodies (mAb) corresponding to each biomarker to stain the tumor tissue samples. Slides are evaluated with a computerized, fluorescencemicroscopy system . Digital images are acquired through a CCCD camera. An algorithm was developed to process and analyze the digital images allowing direct relation between the amount of a specific protein within the cancer cells of the tumor and response to the corresponding drug. Quantitative measurement of up to five signals in a single cell can be obtained.
The DirectHit Panel for Breast Cancer was validated in retrospective clinical trials conducted at The University of MarylandGreenebaum Cancer Center and Harborview Cancer CenterinBaltimore, MD. One key biomarker was selected as a correspondent to each drug, These biomarkers were identified as playing a significant role in cancer processes and as bearing a mechanistic relation to the action of the specified drug. The drug groups used as treatment and their related biomarkers are as follows: Trastuzumab/HER-2/neu,[9][10][11] Antiestrogens/Estrogen Receptor,[12][13][14][15] Taxanes/beta-tubulin III,[16][17][18][19][20][21] 5FU/Thymidylate Synthase.[22][23][24][25]
In these trials DirectHit analysis of estrogen receptor and HER-2/neu displayed a higher predictive accuracy for treatment outcomes with anti estrogen drugs and Trastuzumab than standard methods. In addition DirectHit displayed exceptional predictive accuracy for chemotherapy response (88%). DirectHit also displayed an extreme specificity for predictions of drug resistance (100%).[26]
The cost of the DirectHit Panel for Breast Cancer is $3500. The use of DirectHit could result in significant cost savings because physicians will be able to customize treatment regimens for patients, eliminating ineffective drugs that would have otherwise been prescribed
If a 50% treatment failure rate is assumed for standard chemotherapy, then the use of the DirectHit Test Panel for Breast Cancer could result in potential savings of approximately $466M in drug costs alone for 40,000 late stage cancer patients in the United States. If ancillary costs are also considered, DirectHit testing could result in a total savings of $566M - $666M.
^Cregger,M, Berger, A. Rimm, DL: Immunochemistry and quantitative analysis of protein expression. Arch Pathol Lab Med 2006; 130, 1026-30
^Moeder CB, Gitnane JM, Moulis SP, Rimm DL: Quantitative, fluorescence-based in-situ assessment of protein expression. Methods in Molecular Biology, 3 February 2009; 520:163-175
^Psyrri A, Yu Z, Weinberger PM: Quantitative Determination of nuclear and cytoplasmic epidermal growth factor receptor expression in oropharyngeal squamous cell cancer by using automated quantitative analysis. Clin Cancer Res (2005); 11: 5856-5862
^Piccart M, Lohrisch C, Di Leo A, Larsimont D: The predictive value of HER2 in breast cancer.
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^Emens LA: Trastuzumab: targeted therapy for the management of HER-2/neu-overexpressing metastatic breast cancer. Am J Ther 2005; 12: 243-53?
^Fornier, M., Risio M, Van Poznak C, Seidman A: HER2 testing and correlation with efficacy of trastuzumab therapy. Oncology 2002; 16:1340-1355
^Swain SM, Wilson JW, Mamounas EP, Bryant J, Wickerham DL, Fisher B, Paik S, Wolmark N: Estrogen receptor status of primary breast cancer is predictive of estrogen receptor status of contralateral breast cancer. J. Natl. Cancer Inst 2004; 96:516-523
^Yamashita H, Yando Y, Nishio M, Zhang Z, Hamaguchi M, Mita K, Kobayashi S, Fujii Y, Iwase H: Immunohistochemical evaluation of hormone receptor status for predicting response to endocrine therapy in metastatic breast cancer. Breast Cancer 2006; 13: 74-83
^Sonoo H, Kurebayashi J: Predictive factors for response to endocrine therapy in patients with recurrent breast cancer. Breast Cancer 2000; 7: 297-301
^Chang J, Powles, TJ, Allred, C, Ashley SE, Makris A, Gregory RK, Osborne CK, Dowsett M : Prediction of clinical outcome from primary tamoxifen by expression of biologic markers in breast cancer patients. Clinical Cancer Research 2000; 86: 616-621
^Bernard-Marty C, Treilleux IA: Microtubule-associated parameters as predictive markers of docetaxel activity in advanced breast cancer patients: results of a pilot study. Clin. Breast Cancer 2002; 3:341-345
^Chang JC, Wooten EC, Tsimelzon A, Hilsenbeck SG, Gutierrez MC, Elledge R, Mohsin S, Osborne CK, Chamness GC, Allred DC, O'Connell P: Gene expression profiling for the prediction of therapeutic response to docetaxel in patients with breast cancer. The Lancet 2003; 362: 362-369
^Hasegawa S, Miyoshi Y: Prediction of response to docetaxel by quantitative analysis of Class I and III ß-Tubulin Isotype mRNA expression in human breast cancers. Clin Canc Res 2003, 9: 2992-2997
^Paradiso A, Mangia A, Chiriatti A, Tommasi S, Zito A, Latorre A, Shittuli F, Lorusso V: Biomarkers predictive for clinical efficacy of taxol- based chemotherapy in advanced breast cancer. Ann Oncol 2005; 16 :14 - 19
^Noguchi S: Predictive factors for the response to docetaxel in human breast cancers. Cancer Science 2006; 97: 813-820
^Tommasi S, Mangia A: Cytoskeleton and paclitaxel sensitivity in breast cancer: the role of beta-tubulins. Int J Cancer 2007; 120: 2078-85
^Pestalozzi BC, Peterson HF, Gelber RD, Goldhirsch A, Gusterson BA and Trihia H: Prognostic importance of thymidylate synthase expression in early breast cancer. J Clin Oncol 1997; 15: 1923–31
^Nishimura R, Nagao K, Miyayama, H., Matsuda M, Baba K, Matsoka Y, Yamashita H, Fukuda M, Higuchi A, Satoh A, Mizumoto T, Hamamoto R: Thymidylate synthase levels as a therapeutic and prognostic predictor in breast cancer. Anticancer Res 1999; 19: 5621 – 26
^Hakamada Y, Tsuchida, A, Arima M, Kubouchi T, Tokita H, Ota D, Kaise H, Aoki T, Kusama M, Aoki T: Prognostic predictors in breast cancer patients with preoperative 5- fluorouracil-based chemotherapy. Int J Mol Med 2005; 12: 309-14
^Zhen J, Sun J: Thymidylate synthase predicts for clinical outcome in invasive breast cancer. Histol Histopathol 2005; 20:871-78
^Tkaczuk KH, Tait N. S. Ioffe O, Tan, M, Chumsri S, VanEcho, D A. Sutula, M J. Lesko S,. Deamond S, P. Ts’o; Drug Response Indicator Test (DRIT) as a predictive test for treatment outcomes in advanced breast cancer patients (ABC). Clin Oncol 2009 27:15s
Giltrane GM, Molinaro, A, Cheng, H, Robinson A, Turbin D, Gelmon K, Huntsman D, and Rimm DL. Comparison of Quantitative Immunofluorescence with Conventional Methods for Her-2/neu testing With Respect to Trastuzumab Therapy in Metastatic Breast Cancer. Archives of Pathology and Laboratory Medicine, 2008; 132, 1635–1647.
Bertucci F, Birnbaum D, and Goncalves A. Proteomics of Breast Cancer, Principles and Potential Clinical Applications. Molecular & Cellular Proteomics, 2006; 5, 1772–1786.
