Gene therapy will help the treatment of parkinsonism
Gene therapy will restore the effectiveness of Parkinson's disease treatment
Oleg Lischuk, N+1
In the next phase of clinical trials of gene therapy for Parkinson's disease, patients will be injected with a triple dose of the drug VY-AADC01, delivered directly to the brain. To do this, the developer of Voyager Therapeutics has started recruiting a cohort of 20 volunteers, writes MIT Technology Review (Manufacturing Dopamine in the Brain with Gene Therapy).
Parkinson's disease is the second most common neurodegenerative disease (after Alzheimer's disease), which affects up to 10 million people on Earth. It is manifested by tremor, stiffness of movements and other disorders. Their development is associated with the death of dopamine–producing neurons in the striatum and the tire - the brain structures responsible for movement. The main drug for the treatment of Parkinson's disease is levodopa, a dopamine precursor that penetrates the brain. Over time, the effectiveness of this drug decreases, as the production of aromatic L-amino acid decarboxylase (DKA), an enzyme that synthesizes dopamine from levodopa, decreases in the brain.
Voyager Therapeutics has developed a gene therapy drug VY-AADC01, which is a neutralized virus that delivers the DCAA gene to neurons and restores the production of the enzyme. It is injected directly to the midbrain of patients once under the control of MRI.
Drawing from the website ir.voyagertherapeutics.com – VM
Previous clinical trials on a small group of patients confirmed the possibility of delivering a functioning enzyme gene to the brain, but the effectiveness of treatment was insufficient.
During the current phase 1b trials (in which the safety of various doses of the drug is being studied), researchers inject increasing amounts of genetic material into groups of patients. The first two cohorts of participants received 750 billion and 1.5 trillion vector genomes, respectively. The third cohort, whose recruitment has begun now, will be injected with 4.5 trillion genomes each. If the tolerance is good, the dose will be doubled for the fourth cohort.
The activity of DKA in the brain of patients is measured by the metabolism of levodopa labeled with fluoride-18, which is recorded by a PET scanner. The clinical effects of therapy are evaluated by the required dose of levodopa and improvement of motor functions of patients. Voyager Therapeutics staff expect to receive preliminary test results by the end of 2016, however, according to them, improvement has already occurred in several patients. Special hopes are pinned on high doses of the gene drug.
In addition to treating Parkinson's disease, Voyager Therapeutics is developing gene therapy for amyotrophic lateral sclerosis, Huntington's disease, spinal muscular atrophy, Alzheimer's disease, Friedreich's ataxia and pain syndrome. These drugs are still undergoing preclinical trials.
Currently, clinical trials of gene therapy for Parkinson's disease are also being conducted by the US National Institutes of Health (NIH) and the European company Oxford BioMedica. The former inject the growth factor gene into patients in order to repair damaged neurons, and the latter tries to restore the production of dopamine by three key enzymes of its synthesis. According to the Alliance for Regenerative Medicine, cited by MIT Technology Review, neurology now ranks fourth in the number of gene therapy trials conducted after oncology, cardiology and infectious diseases.
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26.08.2016