Patient Dies in Gene Therapy Experiment

The death of a patient enrolled in the clinical trial of an experimental gene therapy treatment has spurred the U.S. Food and Drug Administration (FDA) to halt the trial and begin safety reviews of 28 other gene therapy trials around the country.

According to an FDA press release issued Thursday, the Seattle-based Targeted Genetics Corporation, which conducted the trial, informed the FDA of the death on July 24.

The trial was designed to test the effectiveness of a new treatment for active inflammatory arthritis, which involves a vector -- a particle derived from a virus and used to deliver replacement genes into targeted cells.

Government regulators are still unclear as to what exactly caused the patient's death.

"Targeted Genetics notified FDA earlier that a patient in its trial experienced a serious adverse event," the FDA statement reads. "Even though the cause of the illness wasn't known, and is still uncertain, the agency immediately placed the trial on clinical hold -- meaning no further product can be administered and no new patients can be enrolled."

According to a statement issued by the company on Thursday, the other subjects who were already enrolled in the study will continue to be followed and monitored.

Since the trial began in October 2005, 127 subjects received an initial dose of either the active drug or a placebo, 74 subjects out of the total 127 received a second dose of the active drug, and of those 74 subjects, 55 received two doses of the active drug, the statement reads.

According to the FDA statement, none of the other subjects are reported to have experienced similar complications, and the patient's illness was related in time to the receipt of a second injection of the product.