Article
Clinical gene therapy trials: Were they ethically justified?
Waren bisher durchgeführte klinische Gentherapiestudien ethisch gerechtfertigt?
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Authors
Published: | April 23, 2004 |
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Outline
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Objective
More than 3500 patients have been enrolled in clinical gene therapy trials in less than a decade. The occurrence of even fatal side effects raises the question if all prerequisites to minimize the patients risk have been fulfilled.
Methods
The "OBA Human Gene Transfer Clinical Trials" and "Journal of Gene Medicine, Clinical Trials" databases were screened for approved clinical gene therapy studies. Based on these results a Medline search looking for published results was performed. Resulting papers were analyzed with regard to preclinical data, study protocol, outcomes and side effects.
Results
36 studies using a gene therapy approach in the treatment of gliomas have been approved so far with published results of 13. The HSV-TK suicide gene therapy paradigm was used in 11 investigations. Only two studies provided gene marking results. More or less no published data are available on vector distribution after local injection in animal tumor models or patients. Rare information is found on transduction efficacy, tropism and transgene expression of the applied vector as well as extracellular distribution and viability of on site produced retroviral particles in human tissue. Nevertheless the complication rate in the published trials was up to 8 fold higher in the treated versus the control group. Having this lack of preclinical data in mind the question has to be addressed if under these circumstances clinical, especially Phase III-, studies with several hundred patients are ethically justified.
Conclusions
To minimize patient´s risk it should be required that all relevant clinical parameters had been tested in animal models. Gene marking studies are essential and should be performed as part of Phase I trials. Results of Phase I and Phase II studies should be carefully analyzed before approval of Phase III trials.