Spark Therapeutics, Inc. is a gene therapy company. The Company focuses on treating orphan diseases. It has a pipeline of product candidates targeting multiple rare blinding conditions, hematologic disorders and neurodegenerative diseases. Its pipeline includes a product candidate targeting choroideremia (CHM), which is in a Phase I/II clinical trial and a product candidate for hemophilia A, which is in a Phase I/II clinical trial. Its product investigational candidate, voretigene neparvovec, is intended to treat a genetic blinding condition or inherited retinal disease (IRD). The programs targeting hematologic disorders include SPK-FIX, for which the lead product candidate, SPK-9001, is in a Phase I/II clinical trial for the treatment of hemophilia B, as well as SPK-FVIII for the treatment of hemophilia A. In its SPK-FVIII program for the treatment of hemophilia A, the Company has initiated a dose-escalating Phase I/II clinical trial for its lead product candidate, SPK-8011.