MammaPrint Identifies New Subset Of Breast Cancer Patients

Ruzanna Harutyunyan's picture

Dr. Michael Knauer from the Netherlands Cancer Institute today announced data uncovering a substantial group of traditionally miscategorized low risk HER2+ patients. Agendia's highly accurate breast cancer tumor recurrence test, MammaPrint, was used to differentiate between patients at high and low risk for recurrence.

HER2+ patients are commonly identified as high risk, yet MammaPrint was able to identify a low risk subgroup of HER2+ patients, who subsequently experienced a 10 year disease-free survival of close to 90 percent even in the absence of (neo)adjuvant trastuzumab (Herceptin) and chemotherapy. Additionally, in a subgroup of highly endocrine responsive HER2/NEU positive patients, MammaPrint low risk patients had no relapse.

The results were presented by Dr. Michael Knauer during the 2008 San Antonio Breast Cancer Symposium (SABCS). In the study population of 169 HER2+ patients MammaPrint classified 16 percent of patients as having a good prognosis signature with a 10-year distant disease-free survival (DDFS) of 89 percent, compared to 84 percent of patients classified as having a poor prognosis signature with a DDFS of 64 percent.


MammaPrint's robustness is underscored by the 70 gene panel unique to the test and a resulting gene profile that covers all molecular pathways associated with breast cancer. HER2/NEU-overexpression is observed in 15-20 percent of invasive breast cancers and is widely considered to be a negative prognostic factor. As a result, current treatment guidelines classify all HER2-positive breast cancer patients at high risk of relapse, and recommend trastuzumab and chemotherapy.

MammaPrint accurately identified a subgroup of patients with a good clinical outcome in HER2+ early breast cancer. These patients will be further studied in the ongoing MINDACT-trial (Microarray for Node-negative and 1-3 positive node Disease may Avoid ChemoTherapy) to determine the prospects of withholding chemotherapy and/or trastuzumab in HER2+, MammaPrint low risk patients.

About MammaPrint

MammaPrint is the first 'in vitro diagnostic multivariate index assay' (IVDMIA) cleared by the U.S. Food and Drug Administration (FDA). FDA clearance requires clinical and analytical validation and reporting systems to ensure patient safety issues are addressed. Highly accurate, MammaPrint identifies patients with early metastasis--those patients who are likely to develop metastases within five years following surgery. Several authoritative studies have shown that chemotherapy particularly reduces early metastasis risk. In planning treatment, the MammaPrint test result provides a doctor with a clear rationale to assess the benefit of adjuvant chemotherapy in addition to other clinical information and pathology tests.

All MammaPrint tests are conducted in Agendia's CLIA-certified service laboratory. All other breast cancer recurrence assays currently marketed have not been subject to the rigorous FDA clearance process.



The genetic analysis of MammaPrint predicts which women will have a greater chance of breast cancer recurrence, information that could save many patients from unnecessary chemotherapy. This test looks at the expression of 70 genes linked to breast cancer with an accuracy level of 96.7% as determined by a study published in the New England Journal of Medicine. The correlations of this are vastly superior to those obtained with standard prognostic markers. The 70 genes in a woman's tumor analyzed by MammaPrint predict the 10-year survival of the patient at a significance level over three times greater than existing methods. Existing methods can't distinguish the patients with a high risk for recurrence from those with low risk with camparable accuracy. These new gene expression profiling tests enable the oncologist and breast cancer surgeon to more accurately determine who should be treated and who should not be treated with chemotherapy, but they have been mostly or totally ineffective at identifying clinical responders to various therapies. The molecular MammaPrint laboratory test is a tool for the oncologist. The oncologist should take advantage of all the tools available to him/her to evaluate a patient. And since studies show that only 25-30% of patients do respond to chemotherapy that is available to them (and even less for "targeted" drugs), there should be due consideration to looking at the advantage of molecular and cellular assay tests. The combination of these tests can enhance the ability to distinguish between "low" risk and "high" risk patients. Patients in the "low" risk group can be spared the unnecessary toxicity, particularly associated with ineffective treatment, while those in the "high" risk group, who would benefit from chemotherapy can be pre-tested to see what treatments have the best opportunity of being successful, and offers a better chance of tumor response resulting in progression-free and overall survival. Every breast cancer patient should have their own unique evaluation based on consultation of pathogenic profiles and drug sensitivity testing data. Research and application of these tests are being encouraged by growing patient demands, scientific advances and medical ethics. These tests are not a luxury but an absolute necessity, and a powerful strategy that cannot be overlooked. Sources: N Engl J Med 347:1999-2009, 2002 J Intern Med 264:275-287, September 2008