Phase 2 trial of oncolytic T-VEC virotherapy plus neoadjuvant chemotherapy for nonmetastatic triple-negative breast cancer

Talimogene laherparepvec (T-VEC) is an oncolytic virus hypothesized to enhance triple-negative breast cancer (TNBC) response to neoadjuvant chemotherapy (NAC). A phase 2 trial at Moffitt Cancer Center evaluated T-VEC plus NAC for stage 2-3 TNBC. The patients received five intratumoral T-VEC injections with paclitaxel followed by doxorubicin and cyclophosphamide and surgery. Common T-VEC toxicities were fevers, chills, headache, fatigue, and injection site pain. NAC toxicities were as expected. Among 37 patients, four thromboembolic events occurred. The primary end point of the trial was met with an estimated RCB0 rate of 45.9% and RCB0-1 descriptive rate of 65%. The 2-year disease-free rate is 89% with no recurrences in RCB0-1 patients. Immune activation during treatment correlated with response. The authors conclude that T-VEC plus NAC in TNBC may increase RCB0-1 rates.