In December, we highlighted the results of a phase 1 clinical trial for Parkinson’s disease being run by a company called Voyager Therapeutics (Click here for that post). In that post we also explained that the company is attempting to take a gene therapy product (VY-AADC01) to the clinic.
VY-AADC01 is a virus that is injected into a particular part of the brain (called the putamen), where it infects cells in that area and causes them to produce a lot of a particular protein, called Aromatic L-amino acid decarboxylase (or AADC). AADC is required for turning L-dopa (one of the primary treatments for Parkinson’s disease) into dopamine – which helps to ease the motor features of the condition.
Today, while most people were focused on President Trump’s inauguration, Voyager Therapeutics provided an update on their ongoing trials. Specifically, the company reported an increase in viral infection coverage of the putamen was achieved by VY-AADC01 in their third group (‘cohort’) of subjects. They infected 42% of the putamen compared to 34% in group 2 and 21% in group 1.
In the press release, the company stated:
“The five patients enrolled in Cohort 3 received similar infusion volumes of VY-AADC01 compared to Cohort 2 (up to 900 µL per putamen), but three-fold higher vector genome concentrations, representing up to a three-fold higher total dose of up to 4.5×1012 vector genomes (vg) of VY-AADC01 compared to patients in Cohort 2 (1.5 × 1012 vg). Patients enrolled in Cohort 3 were similar in baseline characteristics to Cohort 1 and 2. The use of real-time, intra-operative MRI-guided delivery allowed the surgical teams to visualize the delivery of VY-AADC01 and continue to achieve greater average coverage of the putamen in Cohort 3 (42%) compared to Cohort 2 (34%) with similar infusion volumes and Cohort 1 (21%) with a lower infusion volume (Figure 1). The surgical procedure was successfully completed in all five patients. Infusions of VY-AADC01 have been well-tolerated with no vector-related serious adverse events (SAEs) or surgical complications in Cohort 3, and all five patients were discharged from the hospital within two days following surgery. The Phase 1b trial remains on track to deliver six-month safety, motor function, and biomarker data from Cohort 3, as well as longer-term safety and motor function data from Cohorts 1 and 2, in mid-2017.”
This update demonstrates that the company is proceeding with increased concentrations of their virus, resulting in a wider area of the putamen being infected and producing AADC. Whether this increased area of AADC producing cells results in significant improvements to motor features of Parkinson’s disease, we shall hopefully begin to find out later this year.
As always, watch this space.
The Science of Parkinson's 
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