Jolee Mohr, 36, died July 24, 22 days after receiving her second injection of an experimental arthritis drug made of genetically engineered viruses.
Robb Mohr said he believes his wife thought the drug would help her, even though the research was to determine the drug's safety, rather than its effectiveness.
The University of Chicago Medical Center, where Jolee Mohr died, is investigating the cause of death.
"By the time she got to us, she was in liver failure and kidney failure, she was on a ventilator and she was septic" or responding to severe infection, hospital spokesman John Easton said.
The hospital will send tissue samples to multiple labs for testing.
Targeted Genetics Corporation of Seattle has halted the study, and more than 100 patients involved are being evaluated, said company spokeswoman Stacie Byars. The company believes it's too early to speculate on the woman's cause of death, Byars said.
Alan Milstein, a New Jersey attorney who is representing Robb Mohr in a possible civil lawsuit, said Jolee Mohr had mild rheumatoid arthritis and hoped for a cure in the experimental therapy.
"She wasn't going to risk her life for science or medicine or the profits of some company," Milstein said.
Rheumatoid arthritis causes inflammation, pain, and swelling of joints. In time, affected joints typically become damaged.
Arthritis means inflammation of the joints. Rheumatoid arthritis (RA) is a common form of arthritis. About 1 in 50 people develop RA at some stage in their life. It can happen to anyone, and it is not a hereditary disease. It can develop at any age, but most commonly starts in middle adult life (aged 40-60). It is three times more common in women than in men.
The severity can vary from mild to severe. Treatments include medication to ease the pain, and medication to slow down the progression of the disease. Surgery is needed in some cases if a joint becomes badly damaged. But there is no cure for the disease.
Attorney Milstein also represented 18-year-old Jesse Gelsinger, who died in 1999 in his fourth day of a gene therapy experiment at the University of Pennsylvania. Gelsinger had suffered from an inherited disorder that blocks the body from properly processing nitrogen.
The Food and Drug Administration concluded that the gene therapy injection intended to try to cure him instead killed him.
Milstein said he's not sure who's to blame for Jolee Mohr's death, but "we certainly believe the death was connected to the research trial she was in."
The experimental drug uses a virus to try and block a substance that fuels the joint inflammation behind crippling forms of arthritis.
Twenty-eight other gene therapy studies have been reported to the FDA that used, or are using, the same virus, called adeno-associated virus or AAV.
The FDA has said that it was not aware of any serious side effects in any of the AAV studies but that as a precaution, officials are reviewing the ones still actively treating patients.
In addition, the National Institutes of Health's advisory committee on gene therapy will meet in September to discuss the potential scientific implications of Mohr's death.