Voyager's Huntington gene therapy faces FDA hold thanks to manufacturing issues

Voyager Therapeutics can’t catch a break—at least, it looks that way for its Huntington disease program. The gene therapy has run into an FDA hold, one year after Sanofi’s Genzyme unit pulled out of a collaboration on that program.

The FDA placed the IND for the program, VY-HTT01, on a clinical hold due to issues with chemistry, manufacturing and controls, the company said in a statement Monday.

“The company expects to receive specific feedback from the FDA on these matters within 30 days and plans to work closely with the agency resolve them and promptly begin the clinical evaluation of VY-HTT01,” Voyager added.

Voyager teamed up with Sanofi in 2015 on multiple gene therapy programs for central nervous system disorders, including Parkinson’s disease and Friedreich’s ataxia as well as Huntington disease. Voyager would take care of R&D activities, working with Sanofi “in a highly collaborative way,” to get the programs through proof of concept.

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At that point, the French pharma could license the programs, with Voyager holding onto the U.S. rights for the Parkinson’s and Friedreich’s ataxia assets and sharing the U.S. profits with Sanofi on the Huntington candidate. Voyager picked up $100 million upfront, with up to $745 million promised in development and sales milestones.

It was not to be.

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Sanofi walked away from the rights to the Parkinson’s program in October 2017, when it was poised to enter phase 2/3. And in June 2019, the French pharma ditched its options for the Friedreich’s ataxia and Huntington programs, too, amending the partnership to get its hands on adeno-associated virus capsids for use in up to two of its own gene therapies for non-CNS indications.

By that time, Voyager had found a new partner for some of those programs. In January 2019, Neurocrine ponied up $165 million upfront for the rights to four gene therapy programs, including those in Parkinson's and ataxia.

Once phase 2 data are in for the Parkinson's program, Voyager could choose to split profits and costs 50-50 with Neurocrine or cede the global rights in return for milestones and royalties. That point will come at the end of phase 1 for the ataxia asset, with Voyager deciding between sharing profits and costs 60-40 or handing over the U.S. rights to Neurocrine.