Dr Gluz on the Rationale for the WSG-TP-II Trial in HR+/HER2+ Early Breast Cancer

Oleg Gluz, MD, chief physician, Breast Center Niederrhein; West German Study Group, discusses the rationale for launching the phase 2 WSG-TP-II trial (NCT03272477) of neoadjuvant endocrine therapy plus trastuzumab (Herceptin) and pertuzumab (Perjeta) in patients with hormone receptor (HR)–positive, HER2-positive early breast cancer.

The rationale for conducting the WSG-TP-II trial stemmed from the desire to explore treatment de-escalation strategies for patients with early-stage, hormone receptor-positive, HER2-positive breast cancer, Gluz begins. Traditionally, these patients receive standard neoadjuvant or adjuvant chemotherapy in combination with trastuzumab and pertuzumab for 18 to 24 weeks. However, given the potential adverse effects and burden of chemotherapy, the study, initiated in 2016, evaluated the possibility of safely reducing or eliminating one component of the standard treatment regimen, he reports. The trial compared 2 de-escalated treatment approaches to determine the safest regimen for patients with early-stage breast cancer without compromising efficacy, Gluz notes.

The WSG-TP-II trial was conducted in Germany and randomly assigned patients into 2 arms, he continues. One group (n = 100) received 12 weeks of neoadjuvant endocrine therapy combined with trastuzumab and pertuzumab, andthe second group (n = 107) received 12 weeks of paclitaxel alongside trastuzumab and pertuzumab. Following surgery, patients received 1 year of standard adjuvant endocrine therapy plus trastuzumab and paclitaxel with or without chemotherapy. The study protocol strongly recommended omitting adjuvant chemotherapy for those who achieved a pathological complete response (pCR) after 12 weeks of neoadjuvant treatment, he explains. Patients who did not achieve pCR in the neoadjuvant setting were recommended to receive adjuvant chemotherapy.

This trial demonstrated that 12 weeks of de-escalated neoadjuvant therapy with endocrine therapy or paclitaxel in combination with 1 year of trastuzumab plus pertuzumab is a safe regimen for chemotherapy de-escalation in this population.

Disclosures: Dr Gluz reports receiving honoraria for lectures and/or consulting and travel from Agendia, Amgen, AstraZeneca, Daiichi Sankyo, Eisai, Exact Sciences, Gilead, Lilly, MSD, Molecular Health, Novartis, Pierre Fabre, Pfizer, Roche, and Seagen.