Single-center phase 1 trial of intratumoral dendritic cells before chemotherapy in HER2-positive breast cancer

Current chemotherapy regimens for patients with early-stage HER2-positive breast cancer are associated with considerable morbidity. A phase 1 trial at Moffitt Cancer Center (Tampa, FL) evaluated alteration of the tumor microenvironment with intratumoral administration of conventional type 1 dendritic cells (cDC1) in combination with trastuzumab and pertuzumab before paclitaxel and surgery for these patients. The trial of 12 patients found that the therapy was safe, with minimal adverse events reported following 6 weekly injections with 2 dose levels of cDC1. The higher dose was associated with enhanced immune effector recruitment and dramatic tumor regression before the initiation of chemotherapy. The authors conclude that intratumoral administration of cDC1 and trastuzumab-pertuzumab before neoadjuvant chemotherapy was well tolerated with manageable adverse effects and resulted in regression of tumors in patients with early-stage HER2-positive breast cancer.