Roche has entered into a definitive merger agreement to acquire Spark Therapeutics a in a cash transaction valued at approximately $4.3 billion. Spark Therapeutics, based in Philadelphia, PA, discovers, develops and delivers gene therapies for genetic diseases, including blindness, hemophilia, lysosomal storage disorders and neurodegenerative diseases. Spark’s lead clinical asset is SPK-8011, a novel gene therapy for the treatment of hemophilia A, which is expected to start Phase III in 2019....