Debate Over Gene Therapy

Researchers at the University of Pennsylvania are investigating the recent death of an 18-year Arizona man who participated in a gene therapy experiment.

This death is the first directly linked with the field of gene therapy that seeks to cure people by giving them new genes.

Jesse Gelsinger was one of 18 participants in the experiment who suffered from a rare metabolic disease. He fell ill twenty-four hours after receiving a dose of medication during the study and died four days later.

Doctors have been experimenting for nine years with gene therapy, trying to cure an array of diseases. Volunteers in this experiment were given genetically engineered viruses to reverse the potentially deadly inflammation that results from their enzyme deficiency, reports CBS News Health Contributer Dr. Bernadine Healy on CBS This Morning.

Jesse suffered from ornithine transcarbamylase deficiency (OTC), a disease that impairs the body's ability to process proteins. The disorder often leads to coma and death in infancy. Gelsinger, who was first diagnosed with OTC at age 2, had coped with the disease through a regimen of medications and a low-protein diet.

"Patients who have this enzyme deficiency are very susceptible to any kind of inflammation," said Dr. Healy. "When you have an infection, you break down proteins, like proteins in your muscles and this can cause this brain injury and brain coma and actually damage, if not death."

"The first 24 hours looked pretty similar to other patients," said Dr. Mark Batshaw, one of the pioneers of OTC research. "After 24 hours, though, he just went rapidly downhill."

Jesse became comatose, his face swelled, his body was jaundiced and his oxygen intake dipped to dangerously low levels. Soon his entire body was swelling, inside and out.

"The doctor said our son was brain dead," Jesse's father, Paul Gelsinger said. "He was symptomatic maybe three times in his life and now we had a vegetable. He didn't have a mind."

Critics will likely blame his death on gene therapy itself, emphasizing need for a slower transition from conducting experiments on lab animals to humans.

"This death will certainly fuel the debate about how fast and how far gene therapy has come," said Jeffrey Kahn, director of the Center for Bioethics at the University of Minnesota Kahn. "But that's a general question we need to ask, and do ask, about all kinds (of medical research). These questions are not unique to gene therapy."

Researchers are still unsure if the dosage or type of virus used caused him to fall ill. The hardest task is identifying the type of genes to be copied and then delivering the new virus into the body, said Dr. Wilson.

The experiment has been halted until researchers can determine the exact nature of his death.

"This kid was as happy as can be," Paul Gelsinger, told The Arizona Daily Star. "He was saying, 'Dad they might be able to come up with a cure.' He wanted to do it and I encouraged him. I was really proud of this kid."

"I don't know why this happened," Batshaw said. "We view him as a hero. He was one of those rare people who tried to help others. In the history of research, these things happen."

Federal officials were expected to send letters this week to more than 100 scientists across the country conducting human research with similar viruses, asking them to report any evidence of trouble.