The father of a Belfast teenager who is suffering from variant CJD has said he is very stable and no longer considered to be terminally ill.
Jonathan's condition is now considered stable
Don Simms first realised his son Jonathan, now 19, was unwell in May 2001.
Jonathan, who was a talented youth footballer, was being a little clumsy and had problems balancing - classic early signs of the prions that cause vCJD to damage the brain.
Doctors first thought he had multiple sclerosis. But Jonathan's illness was later confirmed as vCJD. He was given just months to live.
After a court battle, the family finally won permission for him to be given the experimental drug pentosan polysulphate in January 2003. It had not previously been tested on human beings.
Almost two years later, the family is happy with the results.
"Jonathan is, from the family's point of view, very stable," Mr Simms told BBC Radio Ulster.
"We held a meeting in September of those responsible for his care in the community, because we had to bring in outside services to allow us to sleep," he explained.
"One of the agencies, the hospice, has been long gone because he was not fitting their criteria. The other agency, Marie Curie, deals with patients in the last six or eight weeks. They are now pulling out in January.
"The general consensus is that Jonathan Simms is no longer terminally ill - he is no longer in the last days or weeks of life - we hope they are right."
Mr Simms said the decision to give their son the drug was a "calculated risk based on 20 years of science".
Jonathan requires intensive care
"The feared side effects that it would cause bleeds in the brain, hydrocephalus, fits etc have not happened," he said.
"There was a 100% certainty that Jonathan would not be here today without some form of treatment."
Mr Simms said the use of the drug was still uncharted waters but pointed to new studies being carried out in Japan, France and America.
"We took a chance, we jumped into a safety net, it was a calculated risk because we looked at many compounds, not just pentosan. We were not that desperate to grasp at straws," he added.
"If we had been shown and, it is still the case, that pentosan was causing Jonathan severe pain and stress we would have to take him off that compound, we would have to kiss him and let him go."