Gene Therapy Volunteer

Although Celsinger had the mild form of OTC deficiency, he volunteered for a University of Pennsylvania trial to test the safety and efficacy of increasing doses of an OTC vector because he wanted to help severely affected newborns. He died four days after the vector was injected into a blood vessel in his liver. An autopsy showed that he died of a severe inflammatory response to the adenoviral vector, which led to a blood reaction that caused most of his organs to shut down. 

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Clinical trials, also known as clinical studies, test potential treatments in human volunteers to see whether they should be approved for wider use in the general population. A treatment could be a drug, medical device, or biologic, such as a vaccine, blood product, or gene therapy. Potential treatments, however, must be studied in laboratory animals first to determine potential toxicity before they can be tried in people. Treatments having acceptable safety profiles and showing the most promise are then moved into clinical trials. 

In an attempt to treat ornithine transcarbamoylase deficiency (a disorder of nitrogen metabolism) using adenoviral vectors, a volunteer died of a severe immune response to the vector. This unfortunate result has led to a reevaluation of the safety of viral vectors for gene therapy. 

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