Gene Therapy, Results

Voyager Therapeutics adds proof its gene therapy for Parkinson’s can work, shares soar

Voyager Therapeutics $VYGR says it’s turned an important corner in its development of a gene therapy that can play a major role in rescuing Parkinson’s patients from the inevitable decline associated with their response to levodopa.

The Cambridge, MA-based biotech has fleshed out its early-stage proof-of-concept data on VY-AADC01, offering new data that demonstrate a heightened efficacy for two higher doses of the gene therapy. Executives at Voyager tell me that they’re heartened to see a dose-dependent response in a key biomarker on their therapy’s impact, with improvements in hourly “on” times, a drop in “off” times and better quality of living scores from the 15 patients divided into three therapeutic cohorts.

A low dose of the gene therapy paled in comparison to the two other cohorts in the study, which did not include a placebo group.

Voyager joined a crowd of biotechs in the winners circle on Wall Street this morning, with its shares – up about 10% yesterday – adding an 36% spike Wednesday.

Voyager CEO Steven Paul

“Cohort 2 continues to look great,” Voyager CEO Steve Paul tells me. “We need to wait to get Cohort 3 to 12 months to choose the dose for the pivotal trial.”

But it’s coming. And with it, Voyager is mapping plans to execute a trial that can be used to seek an accelerated approval.

There are all sorts of caveats that apply to this data, aside from the lack of a placebo arm. The numbers of patients involved in this latest update, which follows the first round of positive results from the early trial, remains small. A pivotal will be much more demanding. And Voyager researchers — who earlier recorded a blood clot case in the study — still has to prove that the process can be done completely safely.

But now there’s more solid data to underscore that Voyager’s approach has promise, a rare event in Parkinson’s, one of the toughest diseases in biotech. And they say that a move to insert the gene therapy through the back of the head appears safe and easier to complete.

The gene therapy is designed to complete a simple task. Parkinson’s patients typically respond well to levodopa to provide the dopamine patients need following the death of neurons in the brain. But their response declines, requiring ever higher doses of levodopa with ever diminishing returns. Voyager’s gene therapy introduces an enzyme that converts levodopa to dopamine, and this study underscores that patients were able to get a better effect with lower dosing — a major accomplishment.

“What we’re doing is putting the gene for that enzyme in neurons that are still alive and healthy, artificially allowing the brain region to continue making dopamine,” says Paul, a longtime Eli Lilly vet before he jumped into biotech.

Those dead neurons, adds Paul, aren’t coming back to life. Voyager looks at this as a restorative strategy, which in primates has proved effective 15 years out.

The plan now is to launch a potentially pivotal trial with 40-42 patients in the first half of next year, pointing to a possible BLA if regulators sign off.

Paul says Voyager is right on track during a key transition point for his company, one of a wave of gene therapy biotechs that gained the spotlight in recent years. As Dimension’s problems with hemophilia B proved, along with its recent sale to Regenrx, not all these companies will make it through. But Voyager is still very much in the game.


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