NEW YORK – MeiraGTx on Tuesday said it plans to advance a gene therapy candidate it's developing for Parkinson's disease, AAV-GAD, into a Phase III trial based on positive data from a clinical bridging study.
MeiraGTx's share price rose on the news, opening at $5.85 per share on Tuesday after closing at $4.64 per share on Monday. Shares opened at $5.33 on Wednesday.
New York-based MeiraGTx said the primary study objectives of safety and tolerability were met in the randomized, sham-controlled clinical trial, known as MGT-GAD-025. Within the clinical trial, 14 patients with idiopathic Parkinson's disease and a history of levodopa responsiveness for at least a year received either a sham procedure or one of two doses of the gene therapy.
AAV-GAD, which is infused bilaterally into the subthalamic nucleus, is designed to treat Parkinson's by addressing the dysfunction of circuits that control movement observed in patients with the neurodegenerative disease. The gene therapy aims to "reprogram" these brain circuits by delivering a functional copy of the GAD gene to the brain and enabling production of GABA, a neurotransmitter that can help to normalize circuit function.
Investigators observed improvements from baseline on efficacy endpoints 26 weeks after treatment, including an average improvement of 18 points on Part 3 of the Movement Disorder Society-Unified Parkinson's Disease Rating Scale, which evaluates motor function, in the high-dose group. The scale ranges from zero to 132, with higher scores being more severe.
Patients in the high- and low-dose groups both experienced improvements on the Parkinson's Disease Questionnaire, which comprises a score running from zero to 100 that measures quality of life, with lower scores representing better health. In the high-dose group, patients' scores on average improved by eight points from baseline, and the low-dose group improved by six points.
There were no serious adverse events related to the gene therapy treatment, MeiraGTx said.
"The significant, substantial, and clinically meaningful changes observed in this small, sham-controlled study provide us with a clear path forward in our clinical development strategy and underpin our discussions with regulators in the US, Europe, and Japan," MeiraGTx President and CEO Alexandria Forbes said in a statement.