Phase Ii Trial Of Pembrolizumab In Combination With Nab-Paclitaxel In Patients With Metastatic Her2-Negative Breast Cancer

TPS1124Background: Immunotherapy has shown therapeutic promise in several cancers, including breast cancer. Monotherapy with anti-PD-1/anti-PD-L1 antibodies has demonstrated durable responses in patients with metastatic triple-negative breast cancer (mTNBC) (Nanda et al, JCO 2016) and metastatic estrogen receptor-positive (mER+)/HER2-negative breast cancer (Rugo et al, SABCS 2015). Furthermore, response rates have been increased with combination approaches with chemotherapy (Adams et al, ASCO 2016). Based on these results, we seek to study the anti-tumor efficacy and safety of pembrolizumab (anti-PD-1 antibody) and nab-paclitaxel, the impact of therapy on the tumor microenvironment, and predictive markers of response. Methods: This is an ongoing single-arm open-label multi-cohort phase II study of pembrolizumab and nab-paclitaxel in patients treated with ≤2 prior lines of therapy for metastatic HER2-negative breast cancer (n = 50) (ClinicalTrials.gov: NCT02752685). Thirty patients with mTNBC and 20 patien...