TAILORx: New data on cohort with recurrence score 26-100 shows 93% cancer-free rate at 5 years

A new analysis from TAILORx, the largest ever breast cancer treatment trial, is published today in JAMA Oncology. It reveals the clinical outcomes with chemotherapy in a subset of 1,389 women with a high Recurrence Score (RS) of 26-100. The outcomes are similar to the B20 trial (Paik et al, JCO, 2006). The new data shows that the estimated rate of freedom from recurrence of breast cancer at a distant site was 93% at five years, an outcome much better than expected with endocrine therapy alone. The results are also being featured as late-breaking information at the European Society for Medical Oncology (ESMO) 2019 Congress in Barcelona.

This finding adds to the limited data on outcomes of patients with a high RS of 26-100, treated with taxane and/or anthracycline-containing chemotherapy regimens plus hormone therapy. It adds to the evidence base supporting the use of the Recurrence Score, a 21-tumor gene expression assay, to guide the use of adjuvant chemotherapy in early breast cancer.

TAILORx was designed and conducted by the ECOG-ACRIN Cancer Research Group with primary funding from the National Cancer Institute, part of the National Institutes of Health.

“The initial results of TAILORx gave clinicians high-quality data to inform personalized treatment recommendations for women,” said lead author Joseph A. Sparano, M.D., associate director for clinical research at the Albert Einstein Cancer Center and Montefiore Health System in New York, and vice chair of the ECOG-ACRIN Cancer Research Group. “This new analysis provides the largest data set on outcomes in patients with early breast cancer and high Recurrence Score results. It confirms the importance of using the test to identify the minority of patients who will receive a significant benefit from adding adjuvant chemotherapy to endocrine therapy.”

Between 2006 and 2010, the TAILORx trial enrolled 10,273 women with hormone-sensitive, HER2-negative, axillary node-negative breast cancer at 1,182 sites in the United States, Australia, Canada, Ireland, New Zealand, and Peru. Patients’ tumors were analyzed using the 21-tumor gene expression test and assigned a risk score (on a scale of 0-100) for cancer recurrence.

This analysis pertains to the women in TAILORx who had a score in the high-risk range (26 and above). These women were assigned to receive chemotherapy and hormone therapy, following surgery. High-risk women were given the option to voluntarily join a prospective registry. Sufficient baseline and follow up information was available on 80% of these women (1,389 of 1,737) for inclusion in this analysis. There was a high adherence to chemotherapy assignment (94%).

Physicians were able to select one of several commonly used chemotherapy regimens. The majority of the patients (84%) received taxane and/or anthracycline-containing chemotherapy regimens. The most common regimens were docetaxel/cyclophosphamide (42%), anthracycline without taxane (24%), and anthracycline and taxane (18%). No chemotherapy was administered in 6% (non-adherence) and cyclophosphamide/methotrexate/5-fluoruracil (CMF) was administered in 4%.

Clinical outcomes in TAILORx with chemotherapy and a high RS of 26-100 ranged by type of chemotherapy. Distant recurrence-free interval (DRFI) rates ranged from 92-96% at five years in patients treated with taxane and/or anthracycline therapy. The regimen containing cyclophosphamide, methotrexate and 5-fluoruracil (CMF) had a DRFI rate of 89%.

The expected rates in TAILORx were based on the treatment effect of chemotherapy observed in B20: 79% at five years and 65% at nine years.

The genomic assay used in the trial was the Oncotype DX Breast Recurrence Score(r) test from Genomic Health, Inc., Redwood City, California.

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The ECOG-ACRIN Cancer Research Group (ECOG-ACRIN) is a membership-based scientific organization that designs and conducts cancer research involving adults who have or are at risk of developing cancer. ECOG-ACRIN comprises nearly 1100 member institutions in the United States and around the world. Approximately 12,000 physicians, translational scientists, and associated research professionals from the member institutions are involved in Group research, which is organized into three scientific programs: Cancer Control and Outcomes, Therapeutic Studies, and Biomarker Sciences. ECOG-ACRIN is supported primarily through National Cancer Institute research grant funding, but also receives funding from private sector organizations through philanthropy and collaborations. Its headquarters are in Philadelphia, Pa. For more information, visit http://www.ecog-acrin.org, follow us on Twitter @eaonc, Facebook, and LinkedIn, or call 215.789.3631.

The groundbreaking Trial Assigning Individualized Options for Treatment (Rx), or TAILORx trial, showed that chemotherapy may be avoided in about 70% of women with hormone-receptor-positive, HER2-negative, node-negative breast cancer. This included women older than 50 and with a RS of 11-25 (45%), at any age with a recurrence score of 0-10 (16%), or 50 years old or younger with a recurrence score of 11-15 (8%). The findings suggested that chemotherapy may be considered for the remaining 30% of women with hormone receptor-positive, HER2-negative, node-negative breast cancer: any age with a RS of 26-100 (17%), or 50 years old or younger with a RS of 16-25 (14 percent). The data, released in June 2018 at the American Society of Clinical Oncology annual meeting in Chicago, and published concurrently in the New England Journal of Medicine, helps inform treatment decisions for many women with early-stage breast cancer.

The study was supported in part by the Breast Cancer Research Foundation, Komen Foundation, and the Breast Cancer Research Stamp. The stamp funding provided more than $5 million to the trial. Since 1998, when the charity stamp was authorized by Congress and first issued by the United States Postal Service, more than $86 million has been raised for breast cancer research. The net proceeds from sales of the stamp are transferred to NIH and the Medical Research Program of the Department of Defense to fund breast cancer research.