Dr. Harbeck on Key Results From the WSG ADAPT-TP Trial in HER2+, HR+ Breast Cancer

Nadia Harbeck, MD, PhD, head, Breast Center, chair, Conservative Oncology, Department of Obstetrics and Gynaecology, University of Munich, discusses the key results from the phase 2 WSG ADAPT-TP trial (NCT01779206) in patients with HER2-positive, hormone receptor (HR)–positive early-stage breast cancer.

Presented during the 2021 ESMO Congress, the WSG ADAPT-TP study evaluated the predictive impact of biomarkers after de-escalated neoadjuvant ado-trastuzumab emtansine (Kadcyla) with or without endocrine therapy vs trastuzumab (Herceptin) plus endocrine therapy in this patient population.

The primary end point of the trial was pathologic complete response (pCR), and secondary end points were overall survival and translational research, Harbeck says. RNA expression patterns, PIK3CA mutation status, and molecular subtypes were examined, Harbeck explains.

The results demonstrated that tumor immunogenicity, such as PD-L1 positivity or CD8 positivity, was associated with favorable outcomes and high pCR rates, with the impact on outcome being greater than impact on pCR, Harbeck continues. Additionally, the effect on pCR was superior to that associated with tumor-infiltrating lymphocytes. Therefore, PD-L1 status appears to correlate with response to therapy, Harbeck concludes.