Intralesional immunotherapy as a strategy to treat melanoma

Intralesional immunotherapy supplements systemic treatments and often achieves higher remission rates as compared to systemic therapy. Its indication is metastatic melanoma with limited tumor burden, particularly in loco-regional metastasis and distant soft tissue metastasis.

This review describes intralesional immunotherapy with talimogene laherparepvec (T-VEC), with velimogene aliplasmid (Allovectin-7) and with intralesional interleukin-2. These therapies function exclusively by activating the immune system. Furthermore, Rose Bengal and electrochemotherapy have been included, as bystander effects have been observed with these treatments.

Objective remissions are achieved in a higher percentage with intralesional immunotherapies, such as intralesional interleukin-2 with up to 69% of complete remissions, as compared to systemic treatment. Therefore, intralesional immunotherapy may act as supplement in the armament against metastatic melanoma. In particular, for patients with multiple cutaneous and subcutaneous metastases (20—≥ 100) and in patients with subcutaneous bulky disease intralesional immunotherapy can improve the disease outcome. The exact role of intralesional immunotherapy in the age of immune checkpoint blockade has still to be determined. A number of clinical trials are on the way in order to better understand synergistic actions of intralesional and systemic immunotherapy.