Voyager is one of the gene therapy companies I have been looking at. I was not confident in good results and held off on a position. From a brief look the results look promising. My doubts centered around the delivery method and Vector (AAV2) used. One clever thing they were aiming to do was deliver to neurons that receive signal (not ones that make dopamine) which don’t die.
I also wasn't too optimistic on QURE's PD program which was attempting to improve on an earlier study by improving the delivery in a similar fashion as VYGR which also was developed by the Voyager co-founder (Bankiewicz) but a different gene is delivered in this program.