Kevin Kalinsky, MD, MS, on the RxPONDER Trial Methods

In the phase 3 RxPONDER trial (NCT01272037), investigators evaluated the use of endocrine therapy versus chemotherapy followed by endocrine therapy in women with hormone receptor (HR)–positive, HER2-negative, lymph node–positive breast cancer with a recurrence score between 0 and 25.

Patients with HR–positive, HER2-negative, lymph node–positive breast cancer have an increased risk of recurrence and are typically treated with chemotherapy. Therefore, to prevent potential overtreatment or undertreatment, the 21-gene Oncotype Dx Recurrence Score is used to identify which patients with these disease characteristics can omit chemotherapy.

Investigators launched the RxPONDER trial, in which 5015 patients with a recurrence score between 0 and 25 were randomized to endocrine therapy alone or chemotherapy followed by endocrine therapy. CancerNetwork® spoke with Kevin Kalinsky, MD, MS, acting associate professor in the Department of Hematology and Medical Oncology at Emory University School of Medicine as well as director of the Glenn Family Breast Center and director of breast medical oncology at Winship Cancer Institute of Emory University, about the trial and its methods.

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We prespecified the analysis to look at whether there was a difference in effect for those patients who are postmenopausal versus pre[menopausal]. And there was a separate landmark study called the TAILORx trial [NCT00310180] for patients who had [lymph] node–negative breast cancer, but the same subtype, hormone receptor–positive and -negative [breast cancer]. And they saw in an exploratory analysis that there was a difference depending upon age. I think that when we look at menopausal status, I’m not sure if we were surprised. I think we’re surprised at how different the populations work.