The primary objective is to choose a dose for further investigation by assessing the effect of up to 2 dose levels of pegloticase administered IV Q4 weeks, co-administered with weekly doses of oral MTX, as measured by the sustained normalization of serum uric acid (sUA) to < 6 mg/dL for at least 80% of the time during Month 6 and the duration of sUA to < 6 mg/dL over 24 week treatment period in adult participants with chronic gout refractory to conventional therapy.
This trial is to assess efficacy, safety, blood levels and bodily effects of up to 2 dose levels of intravenous (IV) pegloticase (KRYSTEXXA) infusions at every 4 week intervals (Q4 Weeks) for up to 6 months (Day 1 to 24 weeks with an optional 24 - 48 weeks treatment duration) when given in combination with weekly oral doses of methotrexate (MTX). The goal is to identify an appropriate dose to be administered every 4 weeks to be used for future clinical trials for patients with chronic gout that does not adequately respond to conventional therapy.