Gene Therapy Shows Potential for Parkinson’s Disease

Genome sequencing

Parkinson’s disease spells big trouble for the U.S. and its growing population of aging baby boomers. The ailment may affect over 1 million Americans with 50,000 to 60,000 new diagnosed cases per year. An investigator at the Center for Neurosciences at the Feinstein Institute for Medical Research in Manhasset, New York, has found that experimental gene therapy for Parkinson’s diseases appears to work by rewiring key areas of the brain.

Background to Research

A trial was published back in 2011, where patients got injections of a gene encoding the enzyme glutamic acid decarboxylase (GAD) into the subthalamic nuclei (STN) of their brains. The patients that received the therapy experienced improved movement results—the effects of the treatment were sustained for up to a year.

Feinstein Institute for Medical Research investigators analyzed longitudinal FGD PET scans of brain glucose metabolism and discovered a new brain network reports AlzForum. The gene therapy appears to have activated a new brain network—representing a new potential biomarker for clinical trials.

It suggests that the formation of new brain circuitry could mediate positive effects. Dr. David Eidelberg reports that “shutting down the disease-causing pathways between the STN and the brain’s motor regions appeared to encourage alternative pathways to develop instead.”

The Study

Published in Science Translational Medicine, Dr. Eidelberg and team analyzed PET scans obtained from 15 patients who participated in the gene therapy study—as well as 20 placebo controls. Interestingly, the investigators observed that healthy patients didn’t exhibit the new brain circuit therapy—this suggests that the gene therapy may afford Parkinson’s patients form novel, compensatory brain circuits to control movement or a term Eidelberg coin “adaptive rewiring.”

What does this mean for Parkinson’s symptoms? Constant trembling, for example, represents a debilitating Parkinson’s disease symptom. This trembling is caused by STN overstimulation. The experimental gene therapy appears to reduce the activity of the STN hence benefitting patients.

Caution

Osaka University’s Professor Hideki Mochizuki recently quoted for AlzForum that the “clinical outcome should be compared with deep brain stimulation in terms of safety and efficacy before wide-range application could be envisaged.”

UK-based Gene Therapy Biotech Acquires Rights

AlzForum reported that Eidelberg noted that a British gene therapy venture secured the rights to the AAV2 GAD therapy (the intellectual property). At the end of last year, Eidelberg declined to name the company as there was no public announcement.

As it turns out, that company is MeiraGTx, a company that their website declares was built around a team with deep expertise in gene therapy development. In 2018, they announced their interest in the AAV-GAD gene therapy addressing Parkinson’s disease. Under their pipeline description, they identify the asset, AAV-GAD, as in Phase I/2 stage.

Founded in 2015, they are led by Alexandra Forbes, Ph.D., who spent over a decade working for healthcare-focused hedge funds.

In a recent corporate presentation, they introduce AAV-GAD and current status. They report that the novel approach to the treatment of Parkinson’s disease has now gone through two (2) clinical trials, and the results are encouraging with statistically significant improvement in motor functions. Of course, they note the high unmet need of 300,000 Parkinson’s disease patients in America alone that no longer respond adequately to oral medications.

Financials

MeiraGTx fits a classical pre-revenue biotech model—financing R&D and clinical trials with the public offering and follows on financing. With approximately $6.4 million in revenue, they report annual losses at $70 million. Their market capitalization at present is $632 million. They hold about $250 million in cash.

Lead Research/Investigator

Dr. David Eidelberg, Professor & Head, Feinstein Center for Neurosciences, Feinstein Institute for Medical Research

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