The U.S. Food and Drug Administration granted Voyager Therapeutics’ gene therapy candidate VY-AADC regenerative medicine advanced therapy (RMAT) designation for the treatment of therapy-resistant motor fluctuations in Parkinson’s patients.
The RMAT designation, recently created by the FDA, is given to regenerative medicine products intended to treat, modify, reverse, or cure a serious or life-threatening disease or condition, and that have early clinical evidence supporting their effectiveness.
This designation enables early interactions with the FDA to discuss intermediate evidence to support accelerated approval and meet post-approval requirements.
“The RMAT designation was based on our Phase 1b clinical data with VY-AADC and represents an important milestone for the program and recognition of this gene therapy as a potential treatment for Parkinson’s,” Robert Pietrusko, senior vice president of regulatory affairs and quality assurance at Voyager, said in a press release.
Parkinson’s is characterized by the loss of dopamine-producing neurons in the substantia nigra, a brain region key in controlling movement. Neurons in the substantia nigra release dopamine into an area of the brain called putamen, which contains dopamine receptors.
Although effective in the early stages of Parkinson’s, the effectiveness of levodopa — a standard Parkinson’s treatment — gradually decreases with disease progression. As a result, patients experience longer periods of reduced mobility and stiffness, where medication is not effective — called off periods — and shorter episodes where motor symptoms are controlled with medication, or on periods. This is referred to as motor fluctuations.
An enzyme called 1-amino acid decarboxylase (AADC) regulates the generation of dopamine from levodopa. Because AADC levels are reduced in the putamen of Parkinson’s patients, the conversion of oral levodopa to dopamine is limited.
According to Voyager, VY-AADC has the potential to increase the generation of dopamine in a durable manner, and provide clinically meaningful improvements by restoring motor function and improving symptoms.
Voyager’s ongoing Phase 1b clinical trial in Parkinson’s patients showed that a one-time administration of VY-AADC led to robust and sustained improvements in motor function, as well as marked reductions in the use of levodopa and other medications.
The investigational treatment was well-tolerated, and has not caused any serious adverse events to date.
Besides Parkinson’s, Voyager is collaborating with pharmaceutical companies and academic institutions to develop its gene therapy approach for patients with amyotrophic lateral sclerosis (ALS) due to mutations in the SOD1 gene, Huntington’s, Friedreich’s ataxia, Alzheimer’s, and severe, chronic pain.