Data from Study of Potential Gene Therapy for Blindness Presented Today

Mathew Shanley

At AAO 2017, the 121st Annual Meeting of the American Academy of Ophthamology, this morning, new research was presented exhibiting that a new gene therapy called voretigene neparvovec could treat patients who have lost their sight to Leber congenital amaurosis (LCA).

The data comes from a Phase 2/3 study sponsored by Spark and conducted by collaborators from both the Children’s Hospital of Philadelphia and University of Iowa.

LCA is an inherited retinal degenerative disease that begins in infancy and slowly progresses to complete blindness. Several other eye-related abnormalities occur in patients with the disease, including roving eye movements, deep-set eyes, and sensitivity to bright light. It’s not uncommon for patients with LCA to also experience issues throughout their central nervous systems.

Approximately 1 in 80,000 individuals are affected by LCA, and it can be the result of 1 of 19 different gene mutations.

There aren’t currently any regulated therapies for the condition, however, voretigene neparvovec is under review of the U.S. Food and Drug Administration (FDA) and could be approved by the end of 2017. In July, a biologics license application was submitted to the FDA with Priority Review. The drug would be marketed by Spark Therapeutics as Luxturna.

Opthamologist Stephen R. Russell, M.D. of the University of Iowa and Albert Maguire, M.D. of the Children’s Hospital of Philadelphia are the lead researchers on the trial that treated 29 patients. 93% (n=27) of the patients treated exhibited significant and meaningful improvements to their vision, enough that they could navigate a maze in low to moderate light. Further, the treated patients displayed improvement in light sensitivity and peripheral vision; 2 common shortfalls experienced by these patients.

Subjects of the study were ages 3 years and older, and received a vector in both eyes via subretinal injections during surgeries on separate days.

The gene therapy vector is generated from an adeno-associated virus (AAV) called AAV2-hRPE65v2. The study followed the treated patients for one year with the primary outcome measure being mobility testing, and secondary outcome measures including additional visual and retinal function tests. Supplementary secondary outcome measures were evaluated after 2 years post-treatment and included ophthalmic exams, physical exams, immunology studies, clinical labs, and adverse event (AE) recording.

On October 12, a key advisory panel including 16 experts in the field and comprised by the FDA unanimously recommended approval of the treatment. The next day, Rare Disease Report spoke with Stephen M. Rose, Ph.D., Chief Research Officer for the Foundation Fighting Blindness, who presented as the FDA’s Advisory Committee meeting. Rose noted that “clinicians recognize the impact and effect it can have on patients’ lives.”

The Prescription Drug User Fee Act (PDUFA) date for the drug is January 12, 2018.

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