(ReutersHealth)

Jun 20 - A world expert on prion diseases said on Wednesday his team is working with GlaxoSmithKline to develop a drug to treat Creutzfeldt-Jakob disease. Professor John Collinge, of St. Mary's Hospital, London, said "very promising" results had been achieved in the test tube. "We think it is possible over the next 5 years that we might be able to introduce something that blocks prion replication," he told a news conference at the World Congress of Neurology. He said 150,000 potential drugs had been screened as part of a research programme to find one or more drugs capable of treating the incurable fatal brain disorder that is believed to be caused by exposure to bovine spongiform encephalopathy (BSE) agents in the food chain. Prof. Collinge said: "The strategy we are following is to try and find small molecules which bind selectively to the normal form of the protein and prevent it being turned into the rogue form of the protein. What we do is screen huge chemical libraries." "Our therapeutic target is to stop the process of replication," he explained. "It turns out that the brain is not good at getting rid of prions.

What is going on in these diseases is that the rogue prion is being produced more rapidly than the brain can get rid of [it]." "But if you stop replication, it turns out that the brain an get rid of these prions quite rapidly. It could get rid of half of them in a matter of a few hours. It could probably, over the course of several days, clear the brain. That is certainly what we have seen in experimental studies." "So the hope — the dream — is that if you block prion replication effectively using these pharmaceuticals, the brain may be able to clear the remaining materials over a period of the next days or weeks." Prof. Collinge stressed, however, that a diagnostic test must also be developed to identify infected persons before the rogue prion proteins cause irreparable damage to the brain.