MeiraGTx Planning to Launch New Trial of AAV-GAD in Parkinson’s Patients

MeiraGTx is preparing to launch a new clinical trial of AAV-GAD, its investigational gene therapy for Parkinson’s disease.

The company stated it is planning to file an investigational new drug (IND) application to obtain authorization to initiate the new trial testing the therapy in patients with Parkinson’s later this year or the beginning of 2021.

AAV-GAD is an experimental gene therapy that uses a harmless adeno-associated virus (AAV) to deliver a copy of the glutamic acid decarboxylase (GAD) gene to neurons in the subthalamic nucleus (STN), a brain region involved in movement control and is affected in Parkinson’s disease.

The gene provides instructions to make GAD, an enzyme that is required for the production of gamma-aminobutyric acid (GABA), the the main inhibitory neurotransmitter in the brain that is responsible for preventing excessive neuronal activity. (Neurotransmitters are small molecules that nerve cells use to communicate with each other.)

By increasing the production of GABA in neurons of the STN, AAV-GAD is thought to normalize the neural circuits responsible for controlling body movements, alleviating motor symptoms of Parkinson’s.

Unlike other forms of therapy that can cause complications due to their widespread effects on the brain, AAV-GAD acts only in neurons located in the STN, making it a potentially safer therapeutic option for patients.

Results from previous Phase 1 (NCT00195143) and Phase 2 (NCT00643890) clinical trials have shown that administration of the AAV-GAD gene therapy directly into the STN region resulted in significant motor improvements in Parkinson’s patients, and were maintained for at least a year.

The company also announced it has already initiated the process of manufacturing cGMP (current good manufacturing practices)-grade materials needed for the creation of the different components of AAV-GAD.

This will be facilitated by the launch of a second cGMP facility dedicated to the creation of viral vectors that should become fully operational in 2021. Its first cGMP facility, focused on plasmid production, should be fully operational by the end of this year. (Plasmids are small circular DNA molecules frequently used in genetic engineering to drive the activity of certain genes of interest.)

MeiraGTx is not anticipating the COVID-19 pandemic will have a significant impact on manufacturing procedures, or on current or future clinical trials. The company also added that is working with its development partners and clinical sites to ensure trials carry on as planned, without compromising the safety of patients, healthcare professionals, and employees.

“Our teams in the UK, U.S. and Netherlands are working tirelessly to minimize the disruption caused by the global COVID-19 pandemic and continue our mission of improving the lives of people with serious diseases,” Alexandria Forbes, PhD, president and CEO of MeiraGTx, said in a press release.