The challenge of gene therapy and DNA delivery

It is 10 years since the first gene therapeutic was administered to patient s. Since that time approximately 3500 patients have been treated and althou gh some evidence of gene transfer has been seen it has generally been inade quate for a meaningful clinical response. The major challenges have been de livery of DNA to the target cells and duration of expression. A variety of gene transfer systems have been evaluated and these are summarized with the ir advantages and disadvantages. Encouraging data have been obtained recent ly by a number of workers and there is some optimism that the enormous pote ntial of gene therapy will be realized in the second decade of its developm ent.