The purpose of this study is to evaluate the safety of ALLN-346 in healthy volunteers, in this first in human, single ascending dose study. ALLN-346 is an enzyme that degrades urate in the gastrointestinal tract.

This is a Phase I, randomized, double-blind, placebo-controlled single ascending dose study of orally administered ALLN-346. The study will evaluate the safety and tolerability, inflammation and immunogenicity, pharmacokinetics and pharmacodynamics of ALLN-346 in healthy volunteers. The study consists of a Screening Period, a Treatment Period of 3 days, which includes 1 single day of dosing and 3 days of in-house observation, and a safety Follow-up Period through Day 28 following dosing.

Inclusion Criteria:

• Signed informed consent form
• Incapable of pregnancy, not nursing, and agrees to use an effective method of contraception; males subjects must agree to abstain from sperm donation
• Good general health as determined by medical history and physical examination
• Normal clinical laboratory test results and ECG

Exclusion Criteria:

• Presence or history of any significant cardiovascular, gastrointestinal, hepatic, renal, pulmonary, hematologic, endocrine, immunologic, dermatologic, neurological, psychiatric disease or history of hyperuricemia
• Any other condition (including surgery) known to interfere with the absorption, distribution, metabolism, or excretion of medicines
• Positive screen results for drugs of abuse, alcohol, or cotinine or recent history of drug or alcohol abuse
• Clinically significant abnormal findings on physical examination, vital signs or 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
• Per Investigator judgment, is not an ideal clinical study candidate