WASHINGTON-- Researchers in Houston and Memphis may have accidentally exposed more than two dozen young cancer patients to the virus that causes AIDS in a gene therapy experiment, the *Washington Post *reported on Friday.
The newspaper said the researchers at St. Jude Children's Research Hospital in Memphis and Baylor College of Medicine in Houston knew about the potential problem in December, but did not inform federal regulators until last week.
And only when the problem was about to become public did they start contacting patients and their parents about the possible infections, according to the Post report.
It said researchers and federal officials acknowledged on Thursday that preliminary tests on the gene-based medicine administered to young volunteers suggested the treatment may have been contaminated with HIV-1, the virus that causes AIDS, and HCV, which causes hepatitis C.
Although two tests found evidence of contamination, scientists and government officials emphasized that the scare might prove to be a false alarm, according to the Post report.
The tests that have been performed so far are extremely sensitive and prone to giving "false positive" results on the kinds of samples used. New and more reliable tests are now being conducted by the Food and Drug Administration. In the meantime, the study has been terminated.
The incident follows recent reports about other gene therapy research institutions that have failed to report patient deaths and illnesses properly, raising questions about the fledgling field's ability to protect patients and comply with federal regulations.
In January, the FDA shut down the University of Pennsylvania's gene therapy program after an investigation uncovered multiple serious lapses in patient protections that may have contributed to the death of an 18-year-old volunteer, the first death attributed to gene therapy.
National Institutes of Health officials subsequently revealed that hundreds of deaths and other "adverse events" in gene therapy trials had gone unreported, despite federal rules that require such events to be reported immediately.
The new case also adds to St. Jude's troubles with the National Institutes of Health, which was already investigating the medical center for its handling of patient deaths in a different clinical study and which has had problems with bacterial contamination of some bone marrow preparations.
The Post said scientists involved in the new case described a series of oversights and mistakes dating back to 1995 that led to the current alarm.
The treatment was designed for patients with neuroblastoma, a brain cancer that is the second most common childhood malignancy. It called for a patient's own tumor cells to be removed and enhanced with an immune system gene inserted into the cells by a gene-altered virus. Those cells were then reinjected in an effort to rally the patient's immune system.
Laura Bowman, the study's principal investigator at St. Jude, told the Post she was reviewing the lab's quality control program last fall when she discovered that two volunteers treated a year ago received genetically engineered viruses that had not been properly tested.
In November, she sent some of the lab's gene-altered viruses grown from that "master batch" of cells to an outside laboratory for testing. Twice, those tests showed the presence of DNA from HIV and HCV. When further test results were slow in coming, she said, she decided to contact the FDA last week.
All the volunteers were close to death from recurrences of their cancers, and only a handful of the 20 patients she treated were alive today, Bowman told the paper.
Of six treated at Baylor, four remain alive. All the deaths were from cancer, the researchers said.
Bowman said AIDS testing of surviving patients would probably be recommended only if further tests confirm the contamination. But she and Brenner said that when researchers found out yesterday that The Washington Post had learned of the problem, they decided to contact patient families immediately.
