Hopes, Hypes and Hurdles of Gene Therapy
Expectations of future prospects for gene therapy are high, though successful gene therapy as a routine medical practice is still a long way off. "Fortunately, a vast majority of the scientific community is aware of both the technical and practical limitations of current approaches to gene therapy", said Dr. Inder Verma from the Salk Institute in San Diego/USA in his opening lecture "Gene Therapy - Hopes, Hypes and Hurdles" at the 3rd International Symposium on Gene Therapy in Berlin at the MAX DELBRÜCK CENTER FOR MOLECULAR MEDICINE (MDC) BERLIN BUCH on Friday (April 21st, 1995). However, the intense efforts of basic scientists and clinicians should hasten the transfer of bench science to bedside, Dr. Verma said. Since the first gene therapy trials in 1990 in the USA, over 100 more have been initiated, with most of the trials currently in progress involving treatments for cancer. Dr Verma is a molecular biologist and virologist who heads a special committee of the National Institutes of Health (NIH) that reviews the activities of the Recombinant Advisory Committee (RAC) that evaluates clinical research protocols.
Dr Verma pointed out various difficulties gene therapists face. According to him one of biggest hurdles for gene therapy is the development of more effective systems (vectors) for transferring genes into cells. Some of the most widely studied vector systems are based on socalled retroviruses. However, retroviruses infect only dividing cells, which Dr Verma says, is a serious handicap for in vivo gene delivery. The problem might be overcome by the use of other types of viruses that can infect non-dividing cells, he speculates. To their surprise, gene therapists also encountered the problem that genes transferred via retroviral vectors often fail to be active in the patient. "What is needed now is more basic understanding of the biology of the variety of viruses being used as vectors", stressed Dr. Verma. "Development of alternative delivery systems also need to be vigorously explored." Dr Verma made clear that, in addition to further investigations of vector systems, research should also focus on the body tissues into which genes are being introduced. Despite these difficulties, Dr Verma expressed cautious optimism based on initial results from gene therapy trials on patients with ADA deficiency, a rare, severe immunodeficiency in children.
More than 400 scientists from the United States and various European countries attended the two-day symposium at the MDC. Areas discussed included the development of vector systems for gene delivery and expression, clinical gene therapy trials on familial hypercholesterolemia, cystic fibrosis, and cancer, and the development of models for treatment of genetic diseases, nongenetic diseases and cancer.
The symposium was organised by the research group for gene substitution and cell regulation of the Max Planck Gesellschaft (Max Planck Society) at the MDC together with the MDC itself, for the third time. The first symposium took place in 1993, when gene therapy was still highly controversial in Germany. Today gene therapy is seen by the general public as probably beneficial, according to studies of the Office of Technology Assessment of the German Parliament (Bundestag), and expectations are high that severe diseases can be effectively treated with this approach in the future.
The MDC is one of 16 national research centres in Germany. The MDC, like all other national research centres, obtains most of its funding from the Federal Ministry of Education, Science, Research and Technology in Bonn, with the remaining part coming from the city of Berlin and extramural funding.
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