MeiraGTx is looking to march its Parkinson’s disease treatment forward into phase 3 after the gene therapy improved motor ability and quality of life in a small midphase trial.
A total of 14 patients were given a one-time infusion of either a high or low dose of the therapy, dubbed AAV-GAD, or a sham treatment into their subthalamic nucleus, a brain region that plays a pivotal role in motor control. AAV-GAD delivers a gene that codes for the enzyme that makes the neurotransmitter GABA, which is implicated in the characteristic motor dysfunction of Parkinson’s.
All the patients had idiopathic Parkinson’s, meaning the cause of their disease is unknown, and had a yearlong history of responsiveness to levodopa, a biological precursor to the neurotransmitter dopamine.
At Week 26, the high-dose group had improved by an average of 18 points on the motor function section of the Unified Parkinson's Disease Rating Scale, MeiraGTx said in an Oct. 15 release. There was no statistically significant improvement in the low dose or sham treatment arms.
In a 39-question survey of quality of life called the Parkinson’s Disease Questionnaire, low-dose patients improved by an average of 6 points from baseline at 26 weeks, while high-dose patients improved by 8 points.
“We have now treated a total of 58 patients in this development program in three independent multicenter clinical studies and have seen no [serious adverse events] related to AAV-GAD treatment,” MeiraGTx President and CEO Alexandria Forbes, Ph.D., said in the release. Even with small patient numbers, she said, “AAV-GAD treatment results in significant and clinically meaningful changes in key efficacy endpoints in Parkinson’s disease.”
Dopamine replacement therapy with levodopa is a common treatment for Parkinson’s, but the drug can lose effectiveness over time as the disease continues to progress. AAV-GAD is meant to reprogram brain circuits with a one-time treatment to correct the effects of low dopamine.
“These data demonstrate the impact of using highly targeted local delivery of gene-based therapy to correct the aberrant circuitry that results from the depletion of dopamine in the brain of idiopathic Parkinson’s patients,” Forbes added in the release.
The company is now discussing with regulators in the U.S., Europe and Japan about initiating a phase 3 trial, Forbes said. Patients who completed the phase 2 study also have the option to enroll in a longer-term follow up.
MeiraGTx has already seen some Big Pharma interest, with Sanofi investing $30 million in the New York-based biotech last year for a first look at the company's new data from its range of programs in immunology, inflammation, central nervous disorders and metabolic diseases. At around the same time, MeiraGTx presented preclinical findings showing that its gene therapy for amyotrophic lateral sclerosis prevented the loss of motor neurons in rat and mouse models of the disease.
MeiraGTx wholly owns its own manufacturing facilities in London and Shannon, Ireland, and has an internally developed end-to-end manufacturing process.