Voyager Encounters Regulatory Bump in Parkinson’s Trial
Voyager Therapeutics can’t seem to catch a break. The company announced on December 22nd that their lead program, gene therapy for Parkinson’s disease, has been put on clinical hold by the FDA, following the appearance of certain MRI abnormalities in some patients in a Phase 2 trial (RESTORE-1). In a series of setbacks, first with its Huntington program and now with Parkinson’s, Voyager is grappling to keep its foothold in the gene therapy market.
Voyager teamed up with Sanofi in 2015 to develop multiple gene therapy programs for central nervous system diseases, including Parkinson’s and Huntington’s disease. However, Sanofi turned away from the deal in 2017 and ditched its rights and options for all the programs it made agreements for with Voyager. Neurocrine at this point saw a window of opportunity in Voyager’s Parkinson program, which was entering Phase 2/3 trial, and swooped into a partner on the lead candidate and three others, which Sanofi had left on the table.
The clinical hold for the RESTORE-1 trial comes after the Data Safety Monitoring Board (DSMB) requested pausing of any dosing in the trial till it reviews additional patient-level data from the trial. The trials are expected to start only after all the necessary reviewing is done in early 2021. Meanwhile, the biotech reported that it is investigating the abnormalities and if they mean any harm to the patients and is working closely with the regulatory agencies and the DSMB to determine the next steps for the RESTORE-1 clinical trial.
Lead Gene Therapy Candidate
Voyager’s treatment NBlb-1817 is an investigational gene therapy for Parkinson’s. This brain disorder results from degeneration of nerve cells, which produce dopamine- a chemical messenger involved in the control of movement. Insufficiency of dopamine in the brain causes tremors involuntary muscles, such as legs, hands, arms, jaw, and impaired balance and coordination. Voyager’s therapy is meant to restore normal levels of dopamine in the brain by injecting gene encoding for the AADC enzyme- a protein responsible for producing dopamine. To get the best effect out of the therapy, it is injected directly into the brain using intraoperative monitoring with MRI-facilitated targeted delivery.
This was certainly not expected for the drug, which showed remarkable efficacy data in the Phase 1b trial. In September, Neurocrine and Voyager presented three-year efficacy data from its Phase 1b trial that demonstrated that a one-time treatment with the investigational gene therapy showed a sustained improvement in motor function as well as a reduction in “Off” time- a time when Parkinson’s symptoms often returned due to failure of the medication to work and increased “On” time- a state with no Parkinson’s symptoms. Additionally, 14 out of 15 patients treated with the drug continued to show an improvement in disease staging after three years.
So far, there are no new therapies approved for Parkinson’s disease besides the dopamine replacement therapies that were developed around 50 years ago. While most patients respond well to such therapies, with long-term treatment, the response of the therapy fluctuates and wears off. For such cases, gene therapy provides an exciting option. Presently, there are 25 trials involving Parkinson’s and gene therapy listed on clinicaltrials.gov. However, only a few have been able to deliver results with much cynicism. Since the efficacy results from these trials take years to come, only time will tell if Voyager’s drug will be successful in treating Parkinson’s.
By Ruchi Jhonsa, Ph.D.
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