Gene Therapy Experiments Halted at Tenn. Hospital
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WASHINGTON — Researchers have halted two gene therapy experiments at a hospital in Memphis, Tenn., because of fears that genetically engineered cells being injected into children with cancer might be contaminated with the AIDS and hepatitis viruses.
The self-imposed shutdown at St. Jude Children’s Research Hospital extends beyond a previous federal research suspension there, imposed by the Food and Drug Administration last month. That suspension was triggered by similar concerns about possible contamination of gene therapy infusions, but involved a different experiment with other children. Ultimately, those cells proved to be clean.
Paula Bowman, the doctor overseeing all three St. Jude studies, said Wednesday that the new concerns arose recently during an internal review of her program, which is testing novel treatments for a common childhood cancer called neuroblastoma. The two experiments newly in question call for injections of laboratory-grown neuroblastoma cells that have been genetically engineered to make them more visible to the immune system.
The cells that were given to patients were the offspring of a “master batch” of cancer cells that had been tested for contamination, Bowman said. But she has been unable to confirm that subsequent generations of cells given to patients were also tested as required.
Bowman, who faced criticism last month for not telling federal officials about the previous contamination risk for several months, said that this time she notified the FDA immediately upon discovering the problem last week. “As soon as we figured it out, we called the FDA,” she said.
Forty-two children have already been treated with the engineered cells that are now in question, and some additional children have been treated by a collaborator at Baylor College of Medicine in Texas. Of the 42, Bowman said, 21 are still alive. None is showing indirect evidence of viral infection, such as elevated liver enzyme levels, but none has been directly tested for infection.
Bowman said she was in the process of contacting the children’s parents to inform them of the oversight. She said she hopes to have test results back within two weeks and, if tests show no evidence of contamination, she intends to resume the treatments.
The FDA has said it is investigating the string of errors that led to the first contamination scare, which included several violations of research rules. Agency officials declined to comment on the new problems.
