A neoadjuvant, phase II trial demonstrates efficacy and tolerability of Talimogene laherparepvec in cutaneous basal cell carcinoma (NeoBCC trial)

Cutaneous basal cell carcinoma (BCC) is the most common cancer worldwide. We present a single arm, phase II neoadjuvant trial with the oncolytic virus Talimogene laherparepvec (T-VEC) in 18 patients with difficult-to-resect basal cell carcinomas. Six cycles of T-VEC were applied intralesionally. The primary endpoint of the study, defined as the proportion of patients, who after six cycles of T-VEC (13 weeks) at the time point of surgery, become resectable with primary wound closure without the need for plastic reconstructive surgery like skin flaps or skin grafts, was already achieved after stage I (9/18 patients; 50.0%), thus the study was discontinued for early success. The objective response rate was 55.6% and the complete pathological response rate was 33.3%. Only mild adverse events occurred. The 6-months RFS and OS rates were 100%. T-VEC led to a significant increase of cytotoxic T cells, B cells and myeloid cells, and a decrease of Tregs within the tumor microenvironment. We observed a potent induction of T cell receptor clones of antitumoral and antiviral origin, as well as a strong humoral immune response. Together, neoadjuvant T-VEC represents a viable treatment option for patients with difficult-to-resect BCCs (EudraCT Number 2018-002165-19).