Spark Therapeutics Offers Update on Database Lock for SPK-RPE65 Phase 3 Trial, Expected Release of Top-Line Data in Oct.

Spark Therapeutics, Inc. ONCE today announced database lock for the Phase 3 clinical trial of its lead program, SPK-RPE65, for the treatment of RPE65-mediated inherited retinal dystrophies. The datasets have been transferred to the company's independent external statistical consultants, who have initiated the analysis of the data. Spark anticipates that it will provide top-line results in October. "Locking the database marks an important step toward the completion of our Phase 3 trial and puts us in a position to share top-line results in October," said Jeffrey D. Marrazzo, Co-founder and Chief Executive Officer of Spark. In addition, Spark reported the following modifications to its final SAP: Designation of pupillary light reflex as an exploratory endpoint and the analysis of the mobility test change score for an assigned first eye as a secondary endpoint, resulting in three secondary endpoints – full-field light sensitivity threshold testing, the first eye mobility test change score, and visual acuity – which will be tested hierarchically in that order; and Adjustment to the intent-to-treat (ITT) population (n=31), which will be the main efficacy analysis population, as well as addition of a modified ITT population (n=29) and clarification of a per-protocol population (n=28), both of which will be used as sensitivity efficacy analysis groups. "The modifications we have made to our final SAP will help create a more robust dataset by increasing the overall amount of information derived from the Phase 3 trial, now including certain pre-specified sensitivity analyses," continued Mr. Marrazzo. "As we prepare to receive the data and present top-line results, we remain confident in the trial and believe the steps we have disclosed today will produce an improved data package to support future regulatory filings." Spark management will provide an update on the SPK-RPE65 program, including a review of the final Phase 3 SAP, during a conference call scheduled for tomorrow, September 10, 2015, at 8:30 am ET (details below). Conference Call Details The conference call can be accessed by dialing (855) 851-4526 (domestic) or +1 (720) 634-2901 (international) and entering passcode 33689474. To access a live audio webcast, please visit the "Investors" section at www.sparktx.com. A replay of the call will be available for one week following the call and can be accessed by dialing (855) 859-2056 (domestic) or +1 (404) 537-3406 (international) and entering passcode 33689474 or by visiting our website.