Technology evaluation: Allovectin-7, Vical

Allovectin-7 is a gene transfer product consisting of the human leukocyte antigen HLA-B7 gene co-expressed with the β₂-microglobulin gene. Allovectin-7 is being developed as an immunotherapy approach for a variety of malignancies, with special focus on melanoma, and head and neck cancer. Efficacy results in the phase II setting appear to be promising; an 11% systemic response rate among the intent-to-treat population and 15% response rate in the evaluable population was observed in patients with refractory metastatic melanoma with disease limited to skin, lymph nodes and lung. Stable disease was seen in 19.2% of the intent-to-treat population and 25.9% of the evaluable population in the same group of patients. Treatments has been extremely well tolerated with the most common side effects including mild-to-moderate injection site reactions and flu-like symptons, all of which resolved rapidly and decreased in incidence after the first injection. Current evaluation of the drug includes higher Allovectin-7 doses and injection of multiple tumors in metastatic melonoma patients. A phase III trial comparing Allovectin-7 plus dacarbazine versus dacarbazine in untreated patients with metastatic melanoma has been completed, and preliminary results are soon to be reported. Phase I/II data also indicate promising activity of Allovectin-7 in patients with advanced refractory head and neck squamous cell carcinoma, with 10% of 60 patients achieving partial response and 23% stable disease after one cycle of treatment. Trials of Allovectin-7 as an adjuvant treatment in earlier stages of disease evolution are planned.