Overview of gene therapy clinical progress including cancer treatment with gene-modified T cells.

It is now twenty years since the first legal gene transfer studies were approved, and there has been considerable disappointment in the slow rate of progress that followed the initial studies. Gradually, however, as the limitations of available vectors are acknowledged and overcome, and with advances in our understanding of the molecular and cell biology of genetic diseases and of cancer, unequivocal successes are now being reported. In this paper we describe the remaining major roadblocks to successful gene therapy and outline approaches to overcome them. We also illustrate how genetically modified immune system cells are already being used for the effective treatment of hematological and other malignancies, and how these approaches are being modified so that they can be effective in treating a broader range of malignancies.