Phase II study of direct intralesional gene transfer of allovectin-7, an HLA-B7/beta2-microglobulin DNA-liposome complex, in patients with metastatic melanoma.

Cutaneous melanoma is one of the most rapidly increasing cancers in the United States. Because of the lack of effective treatment options and toxicities of most chemotherapeutic and radiation regimes, immunotherapies such as vaccination therapy represent an attractive approach for patients with advanced melanoma. The purpose of this study was to evaluate the response rate, time to progression, and survival of patients with metastatic melanoma treated by direct intratumoral injection with Allovectin-7 (a plasmid DNA encoding the genes HLA-B7 and beta2-microglobulin complexed with a cationic lipid mixture, DMRIE/DOPE. Fifty-two patients with metastatic melanoma were enrolled in this Phase II study. Therapy consisted of six intratumoral injections of 10 microg of Allovectin-7 over a 9-week period. Treatment was well tolerated. Treatment-related adverse events were mild to moderate, the most frequent of which were ecchymosis, pruritus (and/or discomfort at the injection site), and pneumothoraces. Regression of the injected lesion was observed in 18% of patients, including one complete response, three partial responses, and five minor responses. An overall response rate of 4% (two partial responses) was documented, and nine patients (18%) maintained stable disease for at least 11 weeks. Six patients remained alive 25.1 to 39.4 months from their first injection, including two patients with local (injected tumor) responses and one patient with an overall disease partial response. This study demonstrates that intratumoral administration of Allovectin-7 in metastatic melanoma is safe and can produce both responses in injected lesions and in overall disease. Clinical trials optimizing patient selection and combining Allovectin-7 with other modalities of therapy are currently ongoing in an effort to improve response rates.