An experimental gene therapy treatment did not cause a patient's death earlier this year, according to a federal advisory committee. The National Institutes of Health's Recombinant DNA Advisory Committee announced the findings this morning (Dec. 3) and made recommendations to alter the design of the study, which was cleared by the US Food and Drug Administration to resume last week.

Building upon preliminary findings, which The Scientist reported in September, the RAC presented additional data fingering a systemic fungal infection and massive retroperitoneal hemorrhage as the primary causes of 36-year-old Jolee Mohr's death in July.

RAC chairman Howard Federoff suggested that the trial should boost hematological monitoring of patients and said that the treatment should not be administered to patients who show physiological signs of infection prior to treatment, or those who have histories of opportunistic infection. Federoff also said that informed consent forms in this study should be revised to mention Mohr's death and to discuss the importance of autopsy should an adverse event occur again.

Mohr died on July 24th, three weeks after she had received her second dose of an experimental treatment for rheumatoid arthritis. The treatment was delivered via an adeno-associated viral vector, and was part of a phase I/II clinical trial conducted by Seattle-based drug company Targeted Genetics.

A RAC team, consisting of NIH scientists, representatives from Targeted Genetics and researchers from FDA and the University of Chicago (where Mohr was taken just prior to her death), has been investigating Mohr's death since July.

In today's meeting, RAC executive secretary Jacqueline Corrigan-Curay presented additional data gleaned from autopsy, hematological, and PCR analysis that point to histoplasmosis, an aggressive fungal infection, and a large abdominal hemorrhage that resulted in organ failure as the main causes of Mohr's death.

Corrigan-Curay said that tests could not identify significant quantities of the experimental vector, the therapeutic gene, or the transgene product outside the site of Mohr's injection (her right knee). This suggests that the gene therapy was not involved in the organ failure that ultimately killed Mohr. Though investigators deemed it unlikely, the RAC investigation could not rule out that Mohr's death was due to an immune response her body mounted against the treatment.

Federoff said that more data should be collected, especially relating to Mohr's use of immunosuppressant arthritis drugs at the time of the experimental treatment. "The potential role of immunosuppressant in altering the risks to subjects enrolled in gene transfer trials needs to be carefully considered," he said.

Federoff also revisited a questioned raised by Mohr's widower, Robb Mohr, during September's RAC meeting. At that meeting, Federoff said, Mohr asked if his wife would have died had she not been involved in the Targeted Genetics trial. "Despite every effort that was conceivable," Federoff said, "we are still missing key pieces of information" about the state of Mohr's immune system preceding her death and its reaction to the experimental gene transfer treatment.

"At this point in time," he said, "we can't answer his question."