Gene therapy is the introduction of new genetic material to damaged genes or cancer cells. The goal of gene therapy is to replace damaged cells with healthy ones, or to make cancer cells more sensitive to the effects of the immune system, immunotherapy, and chemotherapy.

Clinical trials for melanoma are investigating the following approaches in gene therapy:

• Cytokines are proteins that stimulate the activity of immune cells. In one avenue of research, a patient's melanoma cells are removed and a gene is inserted that causes melanoma cells to make cytokines. The altered melanoma cells are then injected back into the patient, with the expectation that they will trigger an immune response.
• Gene-based immunotherapy introduces antigen genes into tumor cells in order to stimulate an immune response. Allovectin-7 is a gene-based drug that contains the antigen gene HLA-B7. When injected directly into melanoma tumors, this antigen may alert the immune system to the presence of tumor cells and trigger a local and systemic immune response against them. Preliminary results in patients with metastatic melanoma were promising. 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.
• Antisense drug therapy involves the use of antisense, the part of DNA responsible for turning off the function of a gene. Augmerosen (G-418) is an antisense drug that turns off the function of the gene BCL-2, which is found at high levels in most melanoma cells and is associated with resistance to chemotherapy. Research suggests that it may act as a shield against anticancer drugs. Preliminary studies using a combination of augmerosen and the chemotherapy drug dacarbazine caused some metastatic melanoma tumors to shrink, even in patients whose cancers had not responded to chemotherapy alone.¹
• Recombinant DNA technology – the ability to take apart and recombine a cell's genetic information – is being investigated for use in melanoma vaccines. See Vaccine Therapy for more information.

For more information on these types of investigations, see Clinical Trials.