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Spark Therapeutics Announces Publication of Positive Follow-Up Data from Phase 1 Trial of Voretigene Neparvovec in The Lancet

Study provides insight into long-term safety and durability of effect of contralateral-eye administration in subjects with childhood-onset blindness caused by RPE65 mutations

PHILADELPHIA, July 01, 2016 (GLOBE NEWSWIRE) -- Spark Therapeutics (NASDAQ:ONCE) announced today the publication in The Lancet of long-term data from a Phase 1 trial of voretigene neparvovec (SPK-RPE65), its most advanced product candidate which has received breakthrough therapy and orphan product designation for the treatment of inherited retinal disease (IRD) caused by mutations in the RPE65 gene.

The publication details safety and efficacy results in 11 subjects that underwent administration of voretigene neparvovec to the contralateral, or second previously uninjected eye. All subjects participated in a prior Phase 1 study in which the worse of the two eyes had been injected with voretigene neparvovec. The publication is the first to report full cohort results of injection of the second eye with an AAV vector, and demonstrated the overall safety of the approach. In addition, the data showed long-term stable and persistent benefit for at least 3 years, with observation ongoing, in retinal and visual function and functional vision after voretigene neparvovec injection.

Please refer to The Lancet’s online publication for additional results from this study.

“We remain encouraged about the durability of benefit shown, underscoring the utility this treatment may have for patients suffering from this debilitating, blinding disorder,” said Jeffrey D. Marrazzo, chief executive officer of Spark.

During the third quarter, Spark plans to present efficacy analyses of both the initial one-year post-administration data from the crossover subjects (n=9) and the two-year follow-up data from the intervention subjects (n=20) in the pivotal Phase 3 trial. In addition, during the fourth quarter, Spark plans to present efficacy analyses on the four-year follow-up data from the relevant cohort of the second Phase 1 trial (n=8). Spark has initiated a rolling submission of the BLA with the FDA on voretigene neparvovec.

About Spark Therapeutics
Spark Therapeutics, a fully-integrated gene therapy company, is seeking to transform the lives of patients with debilitating genetic diseases by developing one-time, life-altering treatments. Spark’s validated gene therapy platform is being applied to a range of clinical and preclinical programs addressing serious genetic diseases, including inherited retinal diseases, liver-associated diseases, such as hemophilia, and neurodegenerative diseases.  Spark’s validated platform has successfully delivered gene therapies with proof-of-concept data in the eye and liver. Spark’s most advanced product candidate, voretigene neparvovec (SPK-RPE65), which has received both breakthrough therapy and orphan product designation, reported positive top-line results from a pivotal Phase 3 clinical trial for the treatment of rare blinding conditions. Spark’s hemophilia franchise has two lead assets: SPK-9001 in a Phase 1/2 trial for hemophilia B and SPK-8011, a preclinical candidate, for hemophilia A.  To learn more, please visit

Spark Cautionary Note on Forward-looking Statements
This release contains "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995, including statements regarding the company's voretigene neparvovec program. Any forward-looking statements are based on management's current expectations of future events and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in, or implied by, such forward-looking statements. These risks and uncertainties include, but are not limited to, the risk that: (i) the data from our Phase 3 clinical trials of voretigene neparvovec may not support a label for the treatment of RPE65-mediated IRDs other than Leber congenital amaurosis (LCA); (ii) the improvements in functional vision and retinal function demonstrated by voretigene neparvovec in our clinical trials may not continue to be sustained over extended periods of time; and (iii) we could experience delays in submitting our regulatory filings of voretigene neparvovec, including our Biologics Licensing Application with FDA and, once submitted, such regulatory filings may not be approved. For a discussion of other risks and uncertainties, and other important factors, any of which could cause our actual results to differ from those contained in the forward-looking statements, see the "Risk Factors" section, as well as discussions of potential risks, uncertainties and other important factors, in our Annual Report on Form 10-K, our Quarterly Reports on Form 10-Q and other filings we make with the Securities and Exchange Commission. All information in this press release is as of the date of the release, and Spark undertakes no duty to update this information unless required by law.


Corporate Contacts:

Stephen W. Webster
Chief Financial Officer
Spark Therapeutics, Inc.Daniel Faga
Chief Business Officer
Spark Therapeutics, Inc.

(855) SPARKTX (1-855-772-7589)

Media Contact:

Ten Bridge CommunicationsDan Quinn
(781) 475-7974

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