Last month a gene therapy trial for arthritis, carried out by US company Targeted Genetics, was halted when following the death of 36-year-old participant Jolee Mohr. Although the exact cause of her death is still unknown, the usually mild fungal infection found throughout Mrs Mohr's body suggests that her immune system was severely impaired, a doctor involved in investigating the incident told the Washington Post newspaper.
'We are confident in the safety of our product and platform and look forward to the opportunity to complete the clinical trials, which is the only way to determine the efficacy and safety profile of this or any other drug candidate', said Stewart Parker, president and chief executive officer of Targeted Genetics. 'All of us at Targeted Genetics are deeply saddened by the unexpected death of this patient', he added.
The death of Mrs Mohr who, prior to taking part in the trial had been relatively healthy, is somewhat of a mystery. For many years Mrs Mohr had been taking a conventional arthritis drug - adalimumab (sometimes called Humira) - which suppresses the production of TNF-alpha, a protein involved in arthritis. However, some patients have joints that fail to respond to this drug, say Targeted Genetics. Although adalimumab is known to make patients susceptible to the same fungal infection that Mrs Mohr had, she had never been affected before despite taking the drug for several years. The gene therapy used in the trial aims to deliver a gene which targets the same TNF-alpha protein as adalimumab, and locally suppresses it in the tissue where it is injected. Mrs Mohr's death raises the question of whether the gene therapy instead spread to other tissues in her body.
The actions of Seattle based company Targeted Genetics have been criticised in the Seattle Post-Intelligencer, who have accused them of 'questionable financial dealings', highlighting the fact that the doctor who recruited Mrs Mohr and other patients, and the board responsible for the ethics of the trial, were both financed by the company. Targeted Genetics are scheduled to make a full presentation to the US National Institutes of Health advisory committee on gene therapy on 18 September.
Attorney Alan Milstein, who is representing husband Robb Mohr in a possible civil lawsuit, said that Mrs Mohr believed the experiment would help her. 'She wasn't going to risk her life for science or medicine or the profits of some company', he told the Washington Post, adding: 'She had mild rheumatoid arthritis'. Any link between Jolee Mohr's death and the gene therapy trial she had been participating in would be a huge blow to the field, particularly as it is not the first death to be associated with trials of the treatment. 'Gene therapy holds a great deal of potential', Arthur Nienhius, president of the American Society of Gene Therapy, told the Washington Post.