title: Unilateral intraputaminal glial cell line-derived neurotrophic factor in patients with Parkinson disease: response to 1 year each of treatment and withdrawal.
abstract: OBJECTIVE
  Glial cell line-derived neurotrophic factor (GDNF) infused unilaterally into the putamen for 6 months was previously shown to improve motor functions and quality of life measures significantly in 10 patients with Parkinson disease (PD) in a Phase I trial. In this study the authors report the safety and efficacy of continuous treatment for 1 year or more. After the trial was halted by the sponsor, the patients were monitored for an additional year to evaluate the effects of drug withdrawal.
  
  
  METHODS
  During the extended study, patients received unilateral intraputaminal infusion of 30 mg/day GDNF at a basal infusion rate supplemented with pulsed boluses every 6 hours at a convection-enhanced delivery rate to increase tissue penetration of the protein. When the study was stopped, the delivery system was reprogrammed to deliver sterile saline at the basal infusion rate of 2 ml/hour. The Unified PD Rating Scale (UPDRS) total scores after 1 year of therapy were improved by 42 and 38%, respectively, in the "off" and "on" states. Motor UPDRS scores were also improved: 45 and 39% in the off and on conditions, respectively. Benefits from treatment were lost by 9 to 12 months after GDNF infusion was halted. At that time, the patients had returned to their baseline UPDRS scores and required higher levels of conventional antiparkinsonian drugs to treat symptoms. After 11 months of treatment, the delivery system had to be removed in one patient because of the risk of infection. In seven patients antibodies to GDNF developed, with no evidence of clinical sequelae. There was also no evidence of GDNF-induced cerebellar toxicity, as evaluated using magnetic resonance imaging analysis and clinical testing.
  
  
  CONCLUSIONS
  Unilateral administration of GDNF results in significant, sustained bilateral benefits. These improvements are lost within 9 months after drug withdrawal. Safety concerns with GDNF therapy can be closely monitored and managed.
authors.affiliation: Department of Anatomy and Neurobiology, the Morris K. Udall Parkinson's Disease Research Center of Excellence, and the Magnetic Resonance Imaging and Spectroscopy Center, University of Kentucky, Lexington, Kentucky 40536-0284, USA. jslevin@uky.edu
authors.forename: John T
authors.initials: JT
authors.lastname: Slevin
authors.forename: Don M
authors.initials: DM
authors.lastname: Gash
authors.forename: Charles D
authors.initials: CD
authors.lastname: Smith
authors.forename: Greg A
authors.initials: GA
authors.lastname: Gerhardt
authors.forename: Richard
authors.initials: R
authors.lastname: Kryscio
authors.forename: Himachandra
authors.initials: H
authors.lastname: Chebrolu
authors.forename: Ashley
authors.initials: A
authors.lastname: Walton
authors.forename: Renee
authors.initials: R
authors.lastname: Wagner
authors.forename: A Byron
authors.initials: AB
authors.lastname: Young
mesh_terms: D000368:Aged; D000978:Antiparkinson Agents / Q000627:therapeutic use; D017321:Clinical Trials, Phase I as Topic; D004334:Drug Administration Schedule; D005260:Female; D051100:Glial Cell Line-Derived Neurotrophic Factor / Q000008:administration & dosage* / Q000009:adverse effects / Q000627:therapeutic use; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000187:drug effects; D010300:Parkinson Disease / Q000188:drug therapy* / Q000503:physiopathology; D011699:Putamen / Q000187:drug effects*; D012720:Severity of Illness Index; D016896:Treatment Outcome
chemical_list: D000978:Antiparkinson Agents; D051100:Glial Cell Line-Derived Neurotrophic Factor; D007980:Levodopa