09 Dec RxPONDER Study Results Demonstrate that the Oncotype DX® Test Can Now Spare Chemotherapy Use
– First results from the independent SWOG Cancer Research Network-led Phase III study to be presented at the 2020 San Antonio Breast Cancer Symposium
– RxPONDER results from over 5,000 women likely to transform the treatment of node-positive breast cancer, as the TAILORx study did in node-negative disease
MADISON, Wis., Dec. 9, 2020 /PRNewswire/ — Exact Sciences Corp. (NASDAQ: EXAS) today announced that data from the Rx for Positive Node, Endocrine Responsive Breast Cancer, or RxPONDER, trial successfully defined the benefit of chemotherapy in early-stage, node-positive breast cancer patients with Oncotype DX Breast Recurrence Score® results of 0 to 25. First results from the study, led by the independent SWOG Cancer Research Network, and sponsored by the National Cancer Institute (NCI), identified the majority of women with 1-3 positive nodes who received no benefit from chemotherapy. The data will be presented on December 10 at the 2020 San Antonio Breast Cancer Symposium (SABCS).
RxPONDER showed a different effect of chemotherapy based on Recurrence Score® results for postmenopausal and premenopausal women. Postmenopausal women with Recurrence Score results 0-25 were not observed to show benefit from chemotherapy and may avoid the associated side effects of the treatment. Importantly, no chemotherapy benefit was observed regardless of the number of affected nodes, tumor grade, or size. Two-thirds of the women in the trial were postmenopausal.
The first results also demonstrated, after a median of five years of follow-up, that premenopausal women with Recurrence Score results 0-25 were observed to have a statistically significant chemotherapy benefit, with an average improvement in distant recurrence rates at 5 years of 3%.
Approximately 85% of women with node- positive disease have Recurrence Score results of 0 to 25. Postmenopausal and premenopausal women with Recurrence Score results 26-100 were not included in the study because investigators reviewed prior studies and determined that this patient group had chemotherapy benefit. The SWOG investigators intend to publish the detailed RxPONDER results in a peer-reviewed publication.
“Every day in clinics around the world, physicians wrestle with the question of how to best treat women with this common form of breast cancer,” said study lead author Kevin Kalinsky, MD, a long-time SWOG investigator and director of the Glenn Family Breast Center at the Winship Cancer Institute of Emory University. “These results are practice changing and demonstrate that the great majority of postmenopausal women can be spared unnecessary chemotherapy and receive only hormone therapy. This should bring more clarity to physicians and some relief for patients.”