Collaboration partners, Neurocrine Biosciences (NBIX -0.79%) and Voyager Therapeutics (VYGR 1.60%) announced data from an early stage clinical trial with Parkinson's disease patients and NBIb-1817, an experimental gene therapy. Three years after a single administration, 14 out of 15 patients are still reporting motor function improvements.

At the moment, NBIb-1817 is in the middle of a phase 2 study that was put on hold in April due to the COVID-19 pandemic. If allowed to restart, the phase 2 RESTORE-1 trial will randomize patients to receive NBIb-1817 or a placebo, then measure for a change in "On" time without troublesome dyskinesia. 

In the background, a medical professional looks at a DNA double helix model in the foreground.

Image source: Getty Images.

This potential new treatment option uses a viral vector to deliver a gene encoding an enzyme that helps Parkinson's disease patients convert levodopa into the dopamine they need. 

Administering NBIb-1817 requires magnetic resonance imaging (MRI) to guide a pair of infusions that deliver the therapy directly into the striatum, a structure deep in the center of the brain. Needles through the skull aren't anybody's idea of a good time, but the side effects that come with daily doses of levodopa aren't any fun either.

For patients with severe Parkinson's disease that has a diminishing response to levodopa, the temporary discomfort that comes with NBIb-1817 treatment seems like a trade-off most will be willing to accept. Three years after a single treatment with NBIb-1817, patients were able to reduce their daily levodopa doses from a baseline of 1500.9 milligrams per day to 1061.4 milligrams per day. Despite reducing their levadopa intake, patients receiving three different dosage strengths of NBIb-1817 improved average "On" time by up to 2.23 hours.