A deal focused on gene therapies to treat severe neurodegenerative conditions saw Neurocrine Biosciences pay Voyager Therapeutics $165 million up front for their adeno-associated virus (AAV) vector platform. In the collaboration Neurocrine will fund the clinical development of four of Voyager’s neurology gene therapy programs: VY-AADC for Parkinson’s disease, VY-FXN01 for Friedreich’s ataxia, and two further programs to be determined. The deal, announced on January 29, could be worth up to $1.7 billion for Voyager in potential milestone payments.

Voyager’s vector is VY-AADC, an AAV-2 vector carrying a therapeutic gene under the control of a cytomegalovirus promoter. In the case of Parkinson’s disease, the therapeutic gene encodes the aromatic l-amino acid decarboxylase (AADC), the enzyme that converts l-DOPA to dopamine. Standard treatment with oral levodopa aims to correct neurotransmitter levels to control parkinsonian symptoms, but its beneficial effects wane over time because the death of AADC-expressing neurons in the substantia nigra reduces the amount of dopamine.

The platform designed by Voyager could correct AADC levels by delivering the AADC gene directly into the putamen by intracranial injection. On the basis of phase 1 data demonstrating safety and improvements in motor function over two years following treatment, VY-AADC was granted Regenerative Medicine Advanced Therapy status by the US Food and Drug Administration in June 2018, and the phase 2 RESTORE-1 trial was initiated in December 2018.

Friedreich’s ataxia is a rare genetic disease caused by a mutation in the frataxin gene FXN that results in decreased expression of the FXN protein, causing progressive muscle weakness, sensory loss and cardiomyopathy. In a preclinical model, Voyager’s VY-FXN0, an AAV-based vector carrying the FXN gene, prevented disease progression for up to a year after one intravenous administration.