Robb Mohr couldn't bring himself to watch her die and he spent his wife's last hours talking with her helpless and puzzled doctors. One vowed to get to the bottom of the illness, and there were several clues to go on.

The most unusual was this: Jolee Mohr got sick the day after her right knee was injected with trillions of genetically engineered viruses in a voluntary experiment to find out if gene therapy might be a safe way to ease the pain of rheumatoid arthritis. She was dead three weeks later.

The sponsor of this nationwide experiment, Targeted Genetics Corp. of Seattle, has halted the work and 127 patients are being evaluated, according to a company spokeswoman. No other problems have been reported, and the company believes patients were adequately informed of the treatment's risks.

U.S. health officials are investigating Mohr's death, and the case is expected to be discussed Monday by advisers to the National Institutes of Health during a meeting in Bethesda, Maryland. There's a lot at stake, including answers for Robb Mohr, and the interests of Targeted Genetics. But there are also questions about how medical studies are done and how much study volunteers are told of the risks.

"To me, it's an avoidable death," Mohr said during an interview at his home amid the cornfields of central Illinois. "And you're going to have to really show me a lot of stuff to convince me that it wasn't."

There have been more than 800 gene therapy studies involving 5,000 U.S. patients since the NIH approved the nation's first human gene transfer study in 1989. Yet there are no approved therapies despite 17 years of research, and the only major success - a cure for the rare inherited immune disorder known as "bubble boy disease" - came with a high cost: leukemia linked in 2003 to the virus that delivered the treatment.

Still, the 1999 death of Arizona teenager Jesse Gelsinger is the only reported fatality that has been definitively linked with a U.S. gene therapy study, an NIH spokesman said. And Dr. Theodore Friedmann, who once headed the NIH committee that oversees gene therapy experiments, said developments in medicine often come with problems, even death.

Even if gene therapy is found to be the cause of Jolee Mohr's death, Friedmann said, the method remains promising.

"There's no question that this event is tragic for the family and the woman involved," he said. "It does simply point to the fact that we have a lot more to learn."

When Dr. Robert Trapp of the Arthritis Center in Springfield told Jolee Mohr about the gene therapy study, she had lived with rheumatoid arthritis for 14 years, her husband said. She kept the pain, stiffness and swelling in her joints under control with medication, and rarely missed time at her data entry job for the Illinois secretary of state.

The study used a genetically engineered virus that can infect cells without causing human disease. In simple terms, the virus is used as a vehicle to carry a new gene into the body. Targeted Genetics hopes the gene will help the body make a protein that would ease arthritis pain.

To enroll in the study, every patient had to have some form of inflammatory arthritis. Jolee Mohr had faith in Trapp, her doctor for seven years, her husband said.

"You trust your physician. He's your doctor. You trust him like you do your minister," Robb Mohr said.

Bioethicists talk of a "therapeutic misconception" ”” a belief among patients in early-stage research that they will get better. Jolee Mohr thought the experimental treatment might relieve the chronic pain in her right knee, her husband said, though this stage of the study was simply to find out if the treatment was safe.

Jolee Mohr signed a 15-page consent form Feb. 12.

The form mentioned some scary possibilities. It said that the genetically altered viruses in the study ”” called tgAAC94 - "could spread to other parts of your body. The risks of this are not known at this time."

Altered viruses can "damage the DNA in the cells of your body by inserting itself into your genes," it went on. "If this happens, it could put you at risk for developing cancer."

And on page 9, it said unknown side effects could result in "pain, discomfort, disability or, in rare circumstances, death."

Mohr was randomly assigned to get the highest dosing level. By all accounts everything was fine after the first shot, in February. But she got sick the day after her second injection, on July 2, vomiting and running a fever.

"She got the injection on the second, we were in the emergency room on the seventh, she was admitted on the 12th," Robb Mohr said. He pointed on a calendar to July 18, the date of his wife's 200-mile (320 kilometers) ambulance ride from a Springfield hospital to Chicago; July 23, when he agreed to a "do not resuscitate" order and, finally, July 24, the date she died.

Trapp, who did not respond to several requests for an interview, enrolled "seven or eight" patients in the gene therapy study, according to his attorney, David Drake. He described Trapp's enrollment procedures only as "standard," and he declined to comment on how much money Trapp's clinic received from Targeted Genetics, fees meant to reimburse costs.

Trapp, 59, has not faced state disciplinary action and his license is active. In 2002, he settled out of court with a patient who sued him for negligence after she developed eye problems known to be a side effect of an arthritis drug he had prescribed.

The investigation into Mohr's death could have steep consequences for Targeted Genetics. The company, which employs 70, has no products on the market and several years ago cut workers and several of its programs.

"A very exciting lead product with the possibility to meet significant unmet need could be jeopardized," said CEO H. Stewart Parker when asked what was at stake for the company.

She said the company believes the study was conducted with the "highest level" of responsibility and that it followed federal guidelines.

Targeted Genetics believes Mohr might have died of a fungal infection that could be blamed on anti-arthritis drugs she was taking, Parker said. She noted that key tests have not yet been done that could link Mohr's death to the gene therapy study; a spokesman at University of Chicago, which is handling the tests, said they are under way but that several are needed to determine the cause of death.

Mohr's family asked the university to lead the investigation into her death, but the FDA is also investigating, spokeswoman Karen Riley said.

The NIH began developing guidelines on gene therapy in the mid-1970s and formed the Recombinant DNA Advisory Committee to review studies, procedures and safety.

Mohr's death tops the agenda for the committee's regularly scheduled quarterly meeting Monday in Bethesda, Maryland. University of Chicago doctors will present autopsy results, though the cause of death and what role the gene therapy might have played are not expected to be ready by then.

Robb Mohr will be there.

"I think it's great that there's companies out there wanting to help people, but I also think there's companies out there that are trying to make millions of dollars on people before they can truly understand what's going on," he said.

Two days before she fell ill, the family went boating. The last family snapshot of Jolee was taken on the boat by their daughter, Toree, and Jolee beams at the young photographer.

"My wife has never looked so beautiful," Mohr said.

"She had nothing to gain from this study," he said. "Why would a 36-year-old mother of a 5-year-old that's going to kindergarten want to participate in something just to see how safe it is on her body? Nothing adds up."

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AP Medical Writer Lindsey Tanner reported from Chicago.

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On the Net:
NIH: http://www.nih.gov and http://bioethics.od.nih.gov
Clinical trials: http://www.clinicaltrials.gov