Voyager Therapeutics Announces Updates from Phase 1b Trial of VY-AADC01 for Advanced Parkinson’s Disease

Voyager Therapeutics, Inc. (NASDAQ:VYGR), a clinical-stage gene therapy company developing life-changing treatments for severe diseases of the central nervous system (CNS), today announced updates regarding the Phase 1b trial of VY-AADC01 for patients with advanced Parkinson’s disease.“The clinical trial of VY-AADC01 is progressing well with all five patients in Cohort 3 successfully completing treatment,” said Bernard Ravina, M.D., M.S., vice president of clinical development at Voyager Therapeutics.  “The neurosurgeons are clearly gaining experience administering VY-AADC01 as evident by the increase in surgical coverage of the putamen achieved in Cohort 3 of 42% compared to 34% in Cohort 2 with similar infusion volumes.  Cohort 1 achieved 21% coverage with a lower infusion volume.  We are very encouraged by the increased surgical coverage of the putamen with VY-AADCO1 due to its high correlation with increased AADC enzyme activity.  The consistency of coverage between patients and the overall favorable safety profile observed in this trial are equally encouraging.”
Increased Coverage of the Putamen Observed in Cohort 3; Six-Month Efficacy Results Expected Mid-2017
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.Figure 1: Coverage of the Putamen with VY-AADC01 is available at https://www.globenewswire.com/NewsRoom/AttachmentNg/5b657736-4f0d-4188-a295-b23eaee252f9
Correlation Data from Cohorts 1 and 2
Interim positive results from the Phase 1b trial from Cohorts 1 and 2 reported in early December 2016 demonstrated that VY-AADC01 dose-dependently improved measures of motor function and enhanced response to levodopa at six and twelve months and that administration of VY-AADC01 was well-tolerated (Figure 2).  Since then, the Company has further analyzed the relationship between surgical coverage of the putamen with VY-AADC01 and enzyme activity of aromatic L-amino acid decarboxylase (AADC) that is responsible for converting levodopa to dopamine in the putamen using [¹⁸F] fluorodopa (or F-Dopa) positron emission tomography (PET).  The results demonstrate that surgical coverage of the putamen was highly correlated with change in AADC enzyme activity measured by F-Dopa PET (r=0.81, p<0.05). Figure 2.  Interim Phase 1b Results Strengthen Clinical Hypothesis