Results
Adeno‐associated virus, serotype‐2 vector carrying glial cell line‐derived neurotrophic factor was tolerated without clinical or radiographic toxicity. Average putaminal coverage was 26%. UPDRS scores remained stable. Ten of thirteen and 12 of 13 patients had increased [18F]FDOPA Kis at 6 and 18 months postinfusion (increase range: 5–274% and 8–130%; median, 36% and 54%), respectively. Ki differences between baseline and 6‐ and 18‐month follow‐up were statistically significant (P < 0.0002).