REduCing Immunogenicity to PegloticasE (RECIPE) Study

Inclusion Criteria: * Men and women \> 18 years of age * Diagnosed with chronic refractory gout\* * Defined as: Persons whose signs and symptoms are inadequately controlled with urate lowering therapy (e.g. xanthine oxidase inhibitors or uricosuric agents) at a medically appropriate dose or for whom these drugs are contraindicated. Exclusion Criteria: * Any serious acute bacterial infection (2 weeks prior to Visit 1), unless treated and completely resolved with antibiotics * Severe chronic or recurrent bacterial infections (such as recurrent pneumonia, chronic bronchiectasis) * Current immunocompromised condition, including current or chronic treatment with immunosuppressive agents * Subjects at risk for tuberculosis. Specifically, subjects with: i) current clinical, radiographic or laboratory evidence of active or latent TB; ii) a history of active TB within the last 3 years even if it was treated; iii) a history of active TB greater than 3 years ago unless there is documentation that the prior anti-TB treatment was appropriate in duration and type * Known Hepatitis B surface antigen-positive or Hepatitis B DNA positive subjects * Known Hepatitis C RNA-positive subjects * Human Immunodeficiency Virus (HIV) infection * G6PD deficiency (tested at Screening Visit 1) * Severe chronic renal impairment (glomerular filtration rate \[GFR\] \<25 mL/min/1.73 m2) or currently on dialysis * Subjects having any transplant surgery requiring maintenance immunosuppressive therapy * Non-compensated congestive heart failure, uncontrolled arrhythmia, treatment for acute coronary syndrome (myocardial infarction or unstable angina), or hospitalization for congestive heart failure within 3 months of screening or uncontrolled blood pressure (\>160/100 mm Hg) at baseline (Screening Visit 1 and Week 0/Baseline visits) * Participants who are pregnant, planning to become pregnant, breastfeeding, or not on an effective form of birth control (defined in Study Protocol section 7.1) * Prior treatment with pegloticase, another recombinant uricase, or concomitant therapy with a polyethylene glycol (PEG)-conjugated drug * Known allergy to pegylated products or history of anaphylactic reaction to a recombinant protein or porcine product * Subjects in whom MMF treatment is contraindicated or considered inappropriate * Recipient of an investigational drug within 4 weeks prior to study drug administration or plans to take an investigational agent during the study * Current liver disease as determined by alanine transaminase ALT or aspartate transaminase (AST) levels \>3 times upper limit of normal * Currently receiving treatment for ongoing cancer, excluding non-melanoma skin cancer * History of malignancy within 5 years other than skin cancer or in situ carcinoma of cervix * Uncontrolled hyperglycemia with a plasma glucose value \>240 mg/dL at screening * Diagnosed osteomyelitis * Individuals with hypoxanthine-guanine phosphoribosyl-transferase (HGPRT) deficiency such as Lesch-Nyhan and Kelley-Seegmiller syndrome * Not good candidate for the study based on opinion of the Investigator (e.g., cognitive impairment) that might create undue risk to the participant or interfere with the participant's ability to comply with the protocol requirements, or to complete the study