A phase 2 study of high-dose Allovectin-7 in patients with advanced metastatic melanoma.

Allovectin-7, a bicistronic plasmid encoding human leukocyte antigen-B7 and beta-2 microglobulin formulated with a cationic lipid system, is an immunotherapeutic agent designed to express allogeneic major histocompatibility complex class I antigen upon intralesional administration. A phase 2 dose-escalation study (VCL-1005-208) was conducted to evaluate the safety and efficacy of Allovectin-7 in patients with metastatic melanoma. Eligible patients had stage III or IV metastatic melanoma recurrent or unresponsive to prior therapy, an Eastern Cooperative Oncology Group performance status 0 or 1, and adequate organ function. Patients with brain or visceral (except lung) metastases, abnormal lactate dehydrogenase, or any lesion greater than 100 cm were excluded. Patients received six weekly intralesional injections followed by 3 weeks of observation and evaluation. Overall response was assessed using Response Evaluation Criteria in Solid Tumors guidelines. Patients with stable or responding disease were eligible to receive additional cycles of Allovectin-7. All 133 patients were evaluated for safety and 127 patients (2 mg, high dose) were evaluated for efficacy. Fifteen patients (11.8%, 95% confidence interval: 6.2-17.4) achieved an objective response with median duration of response of 13.8 months (95% confidence interval: 8.5, not estimable). A histological examination of tissue from two responding patients who had their lesions resected has shown no evidence of melanoma. Median time-to-progression in this study was 1.6 months. In conclusion, these results indicate that high-dose Allovectin-7 seems to be an active, well-tolerated treatment for selected stage III/IV metastatic melanoma patients with injectable cutaneous, subcutaneous, or nodal lesions.