Press release content from Globe Newswire. The AP news staff was not involved in its creation. Spark Therapeutics Announces Preliminary Data from Phase 1/2 Clinical Trial of SPK-8016 in ... Spark Therapeutics, Inc.February 5, 2021 GMT Preliminary data from four participants who received investigational SPK-8016 at a dose of 5X10 11 vg/kg and have no history of FVIII inhibitors show no serious adverse events and stable and durable factor VIII (FVIII) expression at greater than 52 weeks Data show 98-percent reduction in annualized infusion rate (AIR) and 85-percent reduction in annualized bleed rate (ABR) after a follow up of between 15 and 18 months or 5.5 total patient years