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EXPERIMENTAL MEDICINE
Gene-Therapy Researchers
Probe Patients Death
Scientists have acknowledgedsome lapses
in protocol during their recent gene-therapy experiment at Penn in which
an 18-year-old man died, but they dont believe those deviations
were responsible for his death.
During a three-day
meeting called by the Recombinant DNA Advisory Committee (RAC) of the
National Institutes of Health last month (as the Gazette was going
to press), researchers from Penn and the Food and Drug Administration
presented divergent preliminary findings from their separate investigations
into the death of Jesse Gelsinger. Gelsinger died on Sept. 17, four days
after he was injected with a genetically modified cold virus designed
to deliver a potentially corrective gene to his liver ["Gazetteer,"
Nov/Dec].
The meeting was
held to review the safety of the Penn trial and to discuss an NIH proposal
that would require scientists to disclose within 15 days any deaths or
"serious adverse events" that occur in gene-therapy trials. While the
team at Penn was commended by a member of the RAC for its prompt disclosure
of Gelsingers death, FDA officials argued that Gelsinger, who suffered
from a genetic liver disorder, was too sick at the time of his treatment
to have participated in the study. In addition, the agency said it was
not informed of a change in the studys patient-consent form that
prevented participants from learning about the deaths of four monkeys
that had received similar treatment, albeit at higher dosage levels. It
also charged that the research teamled by Dr. James M. Wilson, the
John Herr Musser Professor and Chair of Molecular and Cellular Engineering
who serves as director of the Institute for Human Gene Therapyfailed
to halt the trial and promptly notify the agency by phone or fax when
two previous patients had serious reactions to the treatment. Wilson,
however, stated in a press conference that "months" before Gelsingers
therapy, his team provided the FDA with "comprehensive data," in writing,
about the liver-toxicity levels of all patients. And in a letter to the
Washington Post, he argued that the "informed-consent document
signed by Jesse Gelsinger and all participants in the OTC trial accurately
reflected risks, including death."
Wilson and the
other two researchersDr. Steven Raper, associate professor of surgery,
and Dr. Mark Batshaw of the Childrens National Medical Center in
Washingtonnoted that the ammonia level in Gelsingers blood
(an indication of liver function) fell within the parameters of the trial
protocol at the time of his enrollment. Although the level was slightly
elevated just before he was treated, they believed it could be managed
through intravenous medicines.
The scientists
apologized to the FDA and the advisory committee for diverging from some
of the regulations established for the experiment, which began in April
1997, but in the words of Wilson: "At no time during or prior to this
trial did we in any way expect to see what we saw in Jesse Gelsinger."
According to a statement released by Penns Health System, "A review
of extensive animal studies performed prior to the launch of the clinical
trial and the experiences of the previous 17 participants in the trial
revealed no information that would have predicted the events that led
to Mr. Gelsingers death."
Like the other
study participants, Gelsinger, of Tucson, Ariz., was born with ornithine
transcarbamylase (OTC) deficiency, a condition that prevents the liver
from properly processing the nitrogen in food proteins. The research team
was trying to develop a way to deliver genes directly into the liver cells
to manufacture the missing chemical.
Gelsingers
death was triggered by "an unusual and deadly immune-system response"
to the experimental drug used in the trial, according to the preliminary
findings of the Penn investigators. First Gelsinger developed a fever,
"followed by an injury to the liver," according to a statement released
by the Health System; his blood also clotted abnormally. Those conditions
subsided within 48 hours, and Health System officials stated that he "appeared
to be improving." But on the third day, Adult Respiratory Distress Syndrome
set in as his lungs and other organs failed; he died of oxygen deprivation
and other factors the following day after being taken off life-support.
The Health System
noted that the researchers "remain committed to fully evaluating all potential
leads" and sharing what they learn "in order to prevent another such occurrence."
Among the possible leads discovered during his autopsy was an abnormality
in his bone marrow, which may have predated his treatment.
In his letter to
the Post, Wilson said: "We have been pained and truly humbled"
by Gelsingers "unexpected and tragic death," and vowed that as they
continue their investigation, "we are sustained by the knowledge that
our motives and actions have been consistent with the ideal of advancing
our understanding of this devastating disease so that an effective treatment
may be developed."
Paul Gelsinger,
Jesses father, blamed the FDA for not overseeing the trial more
carefully, but remained supportive of the research team at Penn. "They
have told me everything" about the experiment, he said. "I want them to
continue their work. Thats what Jesse would want."
Dr. Arthur Caplan,
director of Penns Center for Bioethics and Trustee Professor of
Bioethics in Molecular and Cellular Engineering, argued that whats
needed is "not just better federal oversight but more [university-level]
review of subjects in this research and in highrisk research across
the board," because most problems can be better detected at the local
level.
The recent media
scrutiny of human gene therapy is ironic, Caplan added. "A year or so
ago, The New York Times magazine ran a story about this mom who
couldnt get her kid into a gene-therapy trial at Yale because of
the bureaucracy. The same magazine ran a story a year later [about Gelsingers
death], asking, Why are we going so fast with this gene therapy?
We cant make public policy by headline with respect to gene therapy.
Weve got to be in there for the long haul." 
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Gazette Last modified 12/20/99
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