Background: The use of genetically modified autologous tumor cells appears to be a promising approach for cancer therapy. A phase I/II trial was undertaken to define the feasibility, safety and antitumor effects of the autologous vaccine prepared by transferring tag7/PGRP-S gene into malignant melanoma and renal cell carcinoma cells.
Patients and methods: Twenty-one patients (17 with disseminated malignant melanoma and four with metastatic renal cell carcinoma) were enrolled in this study. Cytoreduction was performed in all cases prior to therapy. Autologous tumor cells were transfected with the tag7/PGRP-S gene, irradiated and injected intradermally every 3 weeks.
Results: Vaccinations were well tolerated by all patients, without clinically significant signs of toxicity. Delayed-type hypersensitivity was observed in 48% of cases. Antitumor immune response was observed in 95% of patients. There were no complete or partial responses; however, a minor response was achieved in one patient with renal cell carcinoma. The stabilization of neoplastic disease was observed in eight patients (seven with malignant melanoma and one with renal cell carcinoma). Median time to tumor progression was 3 months.
Conclusions: The approach suggested here appears to be well tolerated and produces a number of durable clinical effects. Further studies are required to determine whether promising effects on immune activation will result in an actual clinical benefit for patients with malignant melanoma and renal cell carcinoma.