Sanofi drops Voyager’s phase 2/3 Parkinson’s gene therapy

Sanofi has walked away from the Parkinson’s gene therapy covered by its $845 million alliance with Voyager Therapeutics. The decision gives Voyager the full global rights to VY-AADC but leaves it without a partner as it gears up for a pivotal global phase 2/3 clinical trial. 

Voyager framed Sanofi’s decision as a result of the Big Pharma’s desire to own the U.S. rights to the gene therapy. The 2015 deal gave Sanofi an option to pick up the ex-U.S. rights to the Parkinson’s asset. At the time, Sanofi was happy enough to put up $100 million and commit to $745 million in milestones for that option and rights to other programs. But, in Voyager’s telling of the story, Sanofi’s attitude has shifted over the past two years.

That shift led to discussions about sharing U.S. rights, but Voyager was unwilling to loosen its grasp on the territory.

“We were not interested in sharing U.S. rights to the program,” Voyager CEO Steven Paul, M.D., said on a conference call with investors to discuss the news. “We see tremendous value .... in retaining rights to our Parkinson’s disease program in the U.S.” 

If, as Voyager says, Sanofi’s decision was motivated by the U.S. rights, rather than doubts about the program, it raises the question of what has changed since it struck the original deal. One possibility is that the failure of uniQure’s Glybera and slow start of GlaxoSmithKline’s Strimvelis in Europe have put Sanofi off the prospect of commercializing the Parkinson’s gene therapy in the region. 

Glybera and Strimvelis were always destined to be niche products, though. Voyager is pitching its candidate at a much bigger market, namely the estimated 10,000 Parkinson’s patients a year that undergo deep-brain stimulation (DBS). Europe played a central role in the rise of DBS and remains a major market. Japan, with its aging population, is another place where VY-AADC may succeed.

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Paul talked up the prospects of VY-AADC in those ex-U.S. territories to investors but acknowledged Europe poses specific challenges.  

“There are considerably more pricing pressures in Europe than there are in the U.S.,” Paul said. 

The task of navigating those pricing pressures may ultimately fall on a new, as-yet-unidentified partner. Voyager is confident it can sell the gene therapy itself in the U.S. and use it as a launchpad for its evolution into a commercial-stage organization. But Paul sounds open to offloading regional rights if a deal comes along that allows Voyager to retain the control it has prioritized.

“It is critical that we lead and manage clinical development ourselves,” Paul said 

On that front, Voyager is now working to keep the development program on track. While accepting Sanofi’s involvement could have helped the ex-U.S. part of the phase 2/3 trial, Paul said Voyager is in good shape going into the study. 

The small volumes of study drug needed for the direct-to-brain administration of the gene therapy allowed Voyager to keep control of manufacturing even before the split from Sanofi. And Paul sees no other aspects of Sanofi’s exit stopping Voyager from starting dosing in the phase 2/3 in the first half of next year. 

Shares in Voyager fell as much as 19% in the wake of the news, before stabilizing down 10% as the biotech’s damage-mitigation efforts kicked in.