Wide-ranging experiments have shown the therapeutic potential as well as the risks of gene therapy. The second memorandum, which has just been presented by the DFG Senate Commission on Genetic Research, makes it clear that gene therapy already shows signs of success in certain areas, such as severe hereditary immunodeficiency diseases, while in other areas there is still considerable need for research. Moreover, the clinical application of gene therapy requires careful risk/benefit assessment, although in this respect it does not differ substantially from other therapeutic approaches.
Gene therapy is defined as the introduction of genes into tissues or cells via gene transfer, with the purpose of deriving a therapeutic or preventative benefit from the function of these genes. Gene transfer is achieved using a vector ? a kind of vehicle that carries the gene. Somatic gene transfer only targets body cells (somatic cells). Introducing genes into the germline is illegal in Germany. The first well-documented gene therapy studies were launched in the early 1990s. By 2005 it was estimated that more than 1,100 gene therapy studies had been conducted worldwide, one-third of them in Europe, and a significant number in Germany. The DFG is currently funding a Priority Programme for research groups, some of which are international leaders in their field, that examine the entry and persistence of gene therapy vectors in target cells.
In spite of continued great difficulties with technical implementation, initial successes in somatic gene therapy are on the horizon, for example in treating adenosine deam inase deficiency and chronic granulomatous disease. There are also initial indicators that point to the efficacy of gene therapy in treating chronic lymphatic leukaemia and haemophilia B. But successes in clinical testing come with their share of setbacks, such as the currently slight margin of therapeutic effectiveness over unwanted side effects. This underscores the necessity to carefully assess risks and benefits and also shows that there is still a dire need for more research on gene therapy. Basic research should be conducted in direct collaboration across disciplines, using animal models and clinical studies. An acute need for research exists, especially regarding the development of efficient and safe vectors for gene transfer.