Neurocrine Ends Work With Voyager on Gene Therapy on Extended Trial Hold

Neurocrine Biosciences announced that it is stopping its work with Voyager Therapeutics to further develop VY-AADC (NBIb-1817) as a potential one-time gene therapy for Parkinson’s disease.

The therapy, by Voyager and being advanced with Neurocrine’s support, is in a Phase 2 clinical trial (NCT03562494) that has been on hold since April 2020.

The ending of this collaboration is effective on Aug. 2, but will not affect joint work in other disease programs, including that of the gene therapy VY-FXN01 for Friedreich’s ataxia, which was part of the original agreement signed by these companies.

In a press release, Voyager stated that Neurocrine’s decision regarding VY-AADC was due to a re-evaluation and re-prioritization of that company’s current pipeline assets.

Voyager added that it will support Neurocrine’s decision, and assist with any matters related to additional clinical and imaging data requests by regulatory agencies or independent board overseeing the RESTORE-1 trial testing VY-AADC in patients — which the companies put on temporary hold in April 2020 due to COVID-19 safety concerns. 

The U.S. Food and Drug Administration (FDA) also placed its own clinical hold on the trial in December, after the monitoring board asked for a pause in trial dosing due to abnormalities found on MRI brain scans of trial participants.

To lift the FDA hold, Neurocrine must conduct an internal assessment to determine if the MRI abnormalities could be a direct result of treatment, as well as provide a mitigation plan to manage potential therapy side effects. It also needs to provide additional data demonstrating that VY-AADC’s potential benefits still outweigh its risks.

Sponsored by Neurocrine, RESTORE-1 is designed to assess the safety, tolerability, and efficacy of a single dose of VY-AADC in Parkinson’s patients with unpredictable motor fluctuations, who failed to respond adequately to conventional oral medications.

The experimental gene therapy uses a harmless version of an adeno-associated virus to deliver the DDC gene, which encodes an enzyme that can convert levodopa into dopamine, to brain cells. It is administered directly to the brain, with MRI monitoring used to facilitate targeted delivery.

By increasing the levels of dopamine, a brain chemical that plays a key role in movement control and whose levels are diminished in patients with Parkinson’s, VY-AADC is expected to help ease the disease’s motor symptoms.

This therapy is also being tested in two Phase 1b Parkinson’s trials — PD-1101 (NCT01973543), now complete, and PD-1102 (NCT03065192), due to end in December.

Two-year data from PD-1102 showed that a single dose of VY-AADC was well-tolerated and helped to lower the duration of off periods — periods in which standard medications cease to be effective and motor symptoms return — by an average of 3.2 hours each day.

Voyager said is now assessing the financial impact Neurocrine’s decision on the future of its Parkinson’s clinical program. It plans to provide an update soon.