A Phase 3, Randomized, Double-Blind, Placebo-Controlled Study to Evaluate the Efficacy and Safety of AG-348 in Not Regularly Transfused Adult Subjects with Pyruvate Kinase Deficiency

INTERVENTION: AG‐348 5 mg, 20 mg or 50 mg BID placebo CONDITION: Pyruvate Kinase Deficiency PRIMARY OUTCOME: The primary endpoint is the hemoglobin responce (HR), defined as a 1.5 g/dL or more increase in Hb concentration from baseline thar is sustained at 2 or more scheduled assessments at Weeks 16, 20, and 24 during the FIxed Dose Period. The individual subject's baseline Hb concentration is defined as the averege of all available Hb concentrations from the central laboratoly for that subject during the Screening Period up to the first dose of treatment. INCLUSION CRITERIA: 1.Have provided signed written informed consent prior to performing any study procedure, including screening procedures. 2.Be aged 18 years or older. 3.Have documented clinical laboratory confirmation of PK deficiency, defined as documented presence of at least 2 mutant alleles in the PKLR gene, of which at least 1 is a missense mutation, as determined per the genotyping performed by the study central genotyping laboratory. 4. Have an Hb concentration less than or equal to 10.0 g/dL regardless of gender (average of at least 2 Hb measurements (separated by a minimum of 7 days) during the Screening Period performed by the study central laboratory). 5. Be considered not regularly transfused, defined as having had no more than 4 transfusion episodes in the 12 month period up to the first day of study treatment and no transfusions in the 3 months prior to the first day of study treatment. 6. Have received at least 0.8 mg oral folic acid daily for at least