International medical experts were today gathering in Belfast to study the "small but significant" progress made by a teenage CJD victim who is undergoing radical treatment.

Scientists and neurologists from as far away as Japan have travelled to Northern Ireland for the special case conference on Jonathan Simms.

The 19-year-old is the first person to have pentosan polysulphate (PPS), which is commonly used to treat cystitis, injected into his brain in an attempt to slow the damage caused by variant Creutzfeldt-Jakob Disease (vCJD).

His father Don organised today's event to demonstrate how Jonathan had responded to the experimental treatment.

He said: "This young man has lived a year longer than predicted, and 10 months over the average life expectancy of variant CJD victims. We have witnessed small but significant changes in his condition since going on to this treatment."

Jonathan, a promising international schoolboy footballer, was struck down by the human form of Bovine Spongiform Encephalopathy (BSE) two years ago.

However, it was only after his family won legal battles at the high courts in London and Belfast last December that health bosses agreed to let infusions of PPS be administered.

Eight months into the treatment, Mr Simms cautioned against labelling the drug a new Penicillin, but admitted that the family was hoping for the best.

Among the experts attending the conference is Professor Katsumi Doh-ura, a Japanese scientist who has conducted the most recent animal studies on PPS.

Dr Stephen Dealler, a microbiologist at Lancaster Hospital, and Dr Nikolai Rainov, a consultant neurosurgeon at the Walton Centre in Liverpool, who have been closely involved with the family from the start, were also due to take part.

Dr Craig Heath, from the Edinburgh CJD Surveillance Unit, and Dr Mark McClean, the Simms' GP in Belfast, have also pledged to attend.

Mr Simms added: "It is all about reporting on Jonathan's progress on PPS. What we hope to do is enable those who had doubts about this medicine and its safety to have a chance to address all the questions through these experts.

"We also want to aid other families who wish to go down the same route without having to jump the hurdles we had to."