Hans Wildiers, MD, PhD, University Hospitals Leuven, KU Leuven, Leuven, Belgium, gives an update on the final results of the randomized placebo-controlled Phase IIb AIPAC trial (NCT02614833) assessing the safety and efficacy of eftilagimod alpha (IMP321) plus paclitaxel in patients with hormone receptor (HR)+/HER2- metastatic endocrine-resistant breast cancer (BC). Whilst there were no statistically significant improvements in progression-free survival (PFS) or in overall survival (OS) for patients treated with eftilagimod alpha, subgroup analyses revealed that patients younger than 65 years old and patients with low baseline monocyte counts had a significantly higher OS with eftilagimod alpha. In addition, it was found that eftilagimod alpha effectively increased the number of cytotoxic lymphocytes. These results need to be confirmed in a randomized Phase III trial. This interview took place during the 36th Society for Immunotherapy of Cancer (SITC) Annual Meeting in Washington, D.C.