Phase 2 Study of Intralesional PV-10 in Refractory Metastatic Melanoma

This international, multicenter, single-arm trial assessed efficacy and safety of intralesional rose bengal (PV-10) in 80 patients with refractory cutaneous or subcutaneous metastatic melanoma. Sixty-two stage III and 18 stage IV melanoma patients with disease refractory to a median of six prior interventions received intralesional PV-10 into up to 20 cutaneous and subcutaneous lesions up to four times over a 16-week period and were followed for 52 weeks. Objectives were to determine best overall response rate in injected target lesions and uninjected bystander lesions, assess durability of response, and characterize adverse events. For target lesions, the best overall response rate was 51 %, and the complete response rate was 26 %. Median time to response was 1.9 months, and median duration of response was 4.0 months, with 8 % of patients having no evidence of disease after 52 weeks. Response was dependent on untreated disease burden, with complete response achieved in 50 % of patients receiving PV-10 to all of their disease. Response of target lesions correlated with bystander lesion regression and the occurrence of locoregional blistering. Adverse events were predominantly mild to moderate and locoregional to the treatment site, with no treatment-associated grade 4 or 5 adverse events. Intralesional PV-10 yielded durable local control with high rates of complete response. Toxicity was confined predominantly to the injection site. Cutaneous bystander tumor regression is consistent with an immunologic response secondary to ablation. This intralesional approach for local disease control could be complementary to current and investigational treatments for melanoma.