Status and potential of gene therapy in clinical medicine - Assessment of an emerging health technology through systematic survey of clinical gene therapy protocols and published results

Objective: Somatic gene therapy is a new method in the rapidly expanding field of molecular medicine. Due to recent encouraging results and the promising prospect for some disease groups, Norwegian health authorities wanted to assess somatic therapy with evidence-based standards for strategic use. This article presents the results of this assessment, discussed in the context of the policy-making process in Norway, including ethical and legislational considerations. Methods: Clinical gene therapy protocols, ongoing or completed with published results, where available, were identified through a systematic survey of descriptive protocols and publications. Preclinical literature was also reviewed. Results: Gene therapy is dominated by preclinical and clinical research. Most of the gene therapy protocols identified are in early phases (phases I and II) with only a few patients in each study. Of the protocols included in the assessment, only three phase III studies are represented. Except for the use of soluble antisense oligonucleotides against cytomegalovirus eye infection, gene therapy is presently not an established treatment modality. Promising results have been observed in treatment of cancer and cardiovascular diseases and, most recently, in inherited severe combined immunodeficiency and hemophilia. Several interesting principles addressing a large panel of conditions are currently being developed and tested. Conclusions: Gene therapy is developing into an important medical concept that needs to be included within the Norwegian healthcare system. It is recommended that the Norwegian Ministry of Health and Social Affairs fund a national program to boost infrastructure in selected scientific groups both in preclinical and clinical research. The national procedures regulating approval of gene therapy trials should be made more efficient while at the same time allowing for proper control and ethical considerations. It is emphasized that gene therapy trials should be carefully monitored for side effects.