Inclusion Criteria:  Male or female, age 18 to 55 years sUA level ≥ 6.8 mg/dL at Screening (hyperuricemia), with or without a diagnosis of gout Not pregnant, not capable of pregnancy, not nursing, and agrees to use an effective method of contraception; males subjects must agree to abstain from sperm donation Normal non-clinically significant abnormalities in vital signs Normal clinical laboratory test results and ECG, which are not considered to be clinically significant  Exclusion Criteria:  Screening eGFR of <60 mL/minute/1.73 m2 History or clinical manifestations of significant metabolic, hematological, pulmonary, cardiovascular, gastrointestinal, neurologic, hepatic, urological, or psychiatric disorders. Presence or history of any other condition (including surgery) known to interfere with the absorption, distribution, metabolism, or excretion of medicines Currently taking any urate-lowering medication within 4 weeks prior to Day 1 (first dosing day) Prior uricase therapy or exposure to recombinant uricase Clinically significant abnormal findings on electrocardiogram (ECG) Positive test result for hepatitis B surface antigen, hepatitis C virus antibody, or human immunodeficiency virus (HIV) antibody Received treatment with or exposure to an Investigational drug or device within 30 days - prior to or during Screening Prior dosing in ALLN-346 clinical study Per Investigator judgment, is not an ideal clinical study candidate