Excitement is running high over the results of a preliminary clinical trial of a new treatment for Parkinson's disease. Under headlines such as “Drug gave me back my life” (BBC News Online, UK, 31 March 2003), the media have been hailing intrastriatal infusions of glial-derived neurotrophic factor (GDNF) as “the most exciting advance in the treatment of Parkinson's disease that has come about in many years” (Michael Zigmond, quoted in The Globe and Mail, Canada, 30 March 2003).

The study described five patients who received GDNF infusions. According to the Globe and Mail, the trial “surprised scientists when all five patients showed measurable improvement.” One of the authors, Clive Svendsen of the University of Wisconsin-Madison, said that the treatment “eliminated the periods of immobility ... and reduced or stopped the involuntary movements common to the disease.”

Neurosurgeon Steven Gill from Frenchay Hospital in Bristol, UK, led the clinical trial. “We are seeing this as a pretty major step,” he told BBC News Online. “It needs to be refined, but we have a chance to reverse the progress of Parkinson's.”

However, the New Scientist (UK, 31 March 2003) sounded a note of caution, pointing out that “more comprehensive studies are needed to determine the drug's efficacy.” In the New Scientist, Peter Heywood from Frenchay Hospital, who was also involved in the trial, stressed that this was a small study with no control group, so “there is a vast opportunity for a placebo effect.”