A Study to Evaluate the Efficacy and Safety of Mitapivat in Pediatric Participants With Pyruvate Kinase Deficiency (PKD) Who Are Regularly Transfused, Followed by a 5-Year Extension Period

A Phase 3, Multicenter, Randomized, Double-blind, Placebo-Controlled Study to Evaluate the Efficacy and Safety of Mitapivat in Pediatric Subjects With Pyruvate Kinase Deficiency Who Are Regularly Transfused, Followed by a 5-Year Open-label Extension Period