Dr. Rimawi on Neoadjuvant Estrogen Deprivation Therapy in HER2+ Breast Cancer

Mothaffar F. Rimawi, MD, associate professor and medical director at the Lester and Sue Smith Breast Center at the Dan L. Duncan Comprehensive Cancer Center at Baylor College of Medicine, discusses the findings of the NSABP B-52 trial, which explored the addition of neoadjuvant estrogen deprivation therapy to docetaxel and carboplatin plus the HER2 inhibitors trastuzumab (Herceptin) and pertuzumab (Perjeta) as treatment for patients with HER2-positive breast cancer.

In the study, which randomized 315 patients, it was found that the addition of estrogen deprivation therapy did not add to the toxicities with the chemotherapy regimen plus HER2-targeted therapy, Rimawi explains. These side effects already include gastrointestinal toxicity, anemia, and possible febrile neutropenia.

Regarding safety, the control arm had a pathological complete response (pCR) rate of 41%, while the addition of estrogen deprivation therapy led to a pCR rate of 46%. This was not found to be a statistically significant difference, he adds. There was a favorable improvement in the experimental arm, none of which were significant.

These findings demonstrate that the addition of estrogen deprivation therapy is safe, but it is not antagonistic. Therefore, this study did not meet its primary endpoint.