Study: NCT03994731

Intervention type: BIOLOGICAL
Group type: EXPERIMENTAL
Intervention: Pegloticase
Description: IV pegloticase 8 mg Q2W

Intervention type: BIOLOGICAL
Group type: PLACEBO_COMPARATOR
Intervention: Pegloticase
Description: IV pegloticase 8 mg Q2W

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: methotrexate
Description: Oral MTX 15 mg weekly

Intervention type: DRUG
Group type: PLACEBO_COMPARATOR
Intervention: methotrexate
Description: Oral MTX 15 mg weekly

Intervention type: DRUG
Group type: PLACEBO_COMPARATOR
Intervention: placebo
Description: Oral placebo for MTX

Intervention type: DIETARY_SUPPLEMENT
Group type: EXPERIMENTAL
Intervention: folic acid
Description: Folic acid 1 mg orally every day beginning at Week -6 until prior to the Week 52 Visit.

Intervention type: DIETARY_SUPPLEMENT
Group type: PLACEBO_COMPARATOR
Intervention: folic acid
Description: Folic acid 1 mg orally every day beginning at Week -6 until prior to the Week 52 Visit.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: gout flare prophylaxis regimen
Description: Prior to beginning the Pegloticase + IMM Period, participants must have been taking at least 1 protocol-standard gout flare prophylaxis regimen (i.e. colchicine and/or nonsteroidal anti-inflammatory drugs and/or low-dose prednisone ≤ 10 mg/day) for ≥ 1 week before the first dose of pegloticase and to continue flare prophylaxis per American College of Rheumatology guidelines \[Khanna D et al. 2012\] for the greater of 1) 6 months, 2) 3 months after achieving target serum urate (sUA \< 6 mg/dL) for participants with no tophi detected on physical exam, or 3) 6 months after achieving target serum urate (sUA \< 5 mg/dL) for participants with one or more tophi detected on initial physical exam that then resolved.

Intervention type: DRUG
Group type: PLACEBO_COMPARATOR
Intervention: gout flare prophylaxis regimen
Description: Prior to beginning the Pegloticase + IMM Period, participants must have been taking at least 1 protocol-standard gout flare prophylaxis regimen (i.e. colchicine and/or nonsteroidal anti-inflammatory drugs and/or low-dose prednisone ≤ 10 mg/day) for ≥ 1 week before the first dose of pegloticase and to continue flare prophylaxis per American College of Rheumatology guidelines \[Khanna D et al. 2012\] for the greater of 1) 6 months, 2) 3 months after achieving target serum urate (sUA \< 6 mg/dL) for participants with no tophi detected on physical exam, or 3) 6 months after achieving target serum urate (sUA \< 5 mg/dL) for participants with one or more tophi detected on initial physical exam that then resolved.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: fexofenadine
Description: For IR prophylaxis, fexofenadine (180 mg orally) taken the day before each infusion and on the morning of each infusion.

Intervention type: DRUG
Group type: PLACEBO_COMPARATOR
Intervention: fexofenadine
Description: For IR prophylaxis, fexofenadine (180 mg orally) taken the day before each infusion and on the morning of each infusion.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: acetaminophen
Description: For IR prophylaxis, acetaminophen (1000 mg orally) taken the morning of each infusion.

Intervention type: DRUG
Group type: PLACEBO_COMPARATOR
Intervention: acetaminophen
Description: For IR prophylaxis, acetaminophen (1000 mg orally) taken the morning of each infusion.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: methylprednisolone
Description: For IR prophylaxis, methylprednisolone (125 mg IV) given over an infusion duration between 10 - 30 minutes, immediately prior to each infusion.