Oncolytic HSV TVEC + Taxane/AC Regimen Yields 46% pCR and 87% 5-Year DFS in Stage II-III TNBC

Talimogene laherparepvec (TVEC) is an intratumoral herpes oncolytic virus engineered to secrete GM-CSF and enhance antitumor immunity. In a single-arm Phase 1/2 study (NCT02779855) involving 46 patients with stage II–III triple-negative breast cancer, TVEC was administered every 2–3 weeks during a 12-week course of paclitaxel (a taxane), followed by the AC chemotherapy regimen (doxorubicin/cyclophosphamide). A pathologic complete response (pCR) was achieved in 45.6% of patients (95% CI, 31–61), and an additional 22% had a low residual cancer burden (RCB-1). After a median follow-up of 70 months, DFS and OS rates were 86.9% and 91.3%, respectively. DFS was 95% among patients who achieved pCR, compared to 80% in the non-pCR group. There were six recurrences (all but one in the non-pCR group) and four deaths. No cases of HSV reactivation or autoimmune events were reported.