In the past five years, two types of therapy have dramatically changed the landscape of treatment for advanced melanoma. Targeted therapies for patients with the defective BRAF gene and “checkpoint blockade” immunotherapies have produced long-term remissions in many melanoma patients and are now being tried against several other types of cancer. Unfortunately, in the majority of patients, the disease eventually progresses or recurs, while other patients have limited partial responses and some do not respond. Yet others have serious adverse reactions and must stop the therapy.
Thus, we still need therapies to use in lieu of, or in conjunction with, these revolutionary systemic therapies. One of the most promising new approaches is intralesional therapy. In this issue of The Melanoma Letter, Dr. Sanjiv Agarwala reviews the intralesional therapies, including the recently FDA-approved T-VEC and several promising experimental strategies.
In patients with inoperable melanoma tumors, injections of T-VEC and other intralesional therapies directly into tumors have had notable success in eliminating or shrinking the injected tumors, and in some patients have also eliminated or shrunk uninjected nearby (“bystander”) lesions. This has spurred hope of developing intralesional strategies with broader systemic effects. These therapies might one day play an extremely important role in combination with the systemic therapies.
Dr. Agarwala explores the most exciting of the intralesional strategies, including T-VEC, electroporated interleukin-12, CAVATAK (CVA21) and PV-10 (rose Bengal). He offers an excellent overview of the promise and remaining challenges in this field.