This article was featured in today's paper. It says that a drug used in the treatment of Type 2 diabetes is being tried on early stage Parkinson's patients. It appears that research has shown that it appears to slow down the loss of brain cells that produce dopamine. This drug also affects levels of immune cells in the brain, which may protect against inflammation and oxidisation damage, both implicated in Parkinsons.
As this drug is already in use, if the trials prove positive, let's hope it is available to Parkinsons patients before too long.