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09-15-2006, 04:33 PM
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In Remembrance
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Here is an example of how misleading a research article can be. This turns out to be an old study. But it was just submitted and published and if you didn't know to question it - it sounds like they are still researching GDNF using the Amgen catheter. It also took us back to square one as we started out saying they used the wrong pump but have since come to believe that actually all pumps worked.
This caused distress among participants who still have this pump in, who know it worked, and it was in reality perhaps something a grad student needed to get published or something. Not saying it is but you get the idea. YEXNR-09292;No.ofpages:9;4C: ARTICLEINPRESS + model Experimental Neurology xx (2006) xxx –xxx www.elsevier.com/locate/yexnr Point source concentration of GDNF may explain failure of phase II clinical trial Michael F. Salvatore 1,YiAi 1, Brent Fischer, Amanda M. Zhang, Richard C. Grondin, Zhiming Zhang, Greg A. Gerhardt, Don M. Gash . Department of Anatomy and Neurobiology and The Morris K. Udall Parkinson’s Disease Research Center of Excellence, University of Kentucky, Lexington, KY 40536, USA Received 23 May 2006; revised 3 July 2006; accepted 17 July 2006 Abstract Significant differences have been reported in results from three clinical trials evaluating intraputamenal infusion of glial cell line-derived neurotrophic factor (GDNF) for the treatment of Parkinson's disease. To determine if problems in drug bioavailability could have contributed to the discrepancies between studies, we have analyzed the distribution of intraputamenally infused GDNF in the rhesus monkey brain using the delivery system and infusion protocol followed in a phase 2 clinical trial that failed to achieve its primary endpoint. I125-GDNF was unilaterally infused into the putamen of three adult rhesus monkeys for 7 days. Three age-and sex-matched animals received vehicle infusions following identical procedures. GDNF levels in the brain, peripheral organs, blood and CSF were quantified and mapped by GDNF immunocytochemistry, GDNF ELISAs and I125 measurements. Infused GDNF was found to be unevenly concentrated around the catheter, with tissue levels dropping exponentially with increasing distance from the point source of the single opening in the catheter tip. The volume of distribution of GDNF around the catheter, as determined by immunocytochemistry, varied over four-fold between animals ranging from 87 to 369 mm3. The concentration of GDNF around the catheter tip and limited diffusion into surrounding brain parenchyma support the hypothesis that drug bioavailability was limited to a small portion (2–9%) of the human putamen in the clinical trial using this catheter and infusion protocol. © 2006 Published by Elsevier Inc. Keywords: GDNF; Putamen; Nonhuman primates; Clinical trial; Drug delivery; Tissue levels paula |
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Ok I tried -back to business
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