"The availability of KRYSTEXXA has brought hope to refractory chronic gout patients who have not responded to conventional therapies and is the first and only FDA approved treatment for RCG," said John H. Johnson, Chief Executive Officer and President of Savient Pharmaceuticals. "We are proud to have results from the Phase III clinical program published in a prestigious peer-reviewed journal, which further demonstrates that KRYSTEXXA represents an important advancement in the treatment of this severe and debilitating disease."
The most commonly reported adverse events, occurring in at least five percent of KRYSTEXXA-treated patients, were gout flare, infusion reaction, nausea, contusion or ecchymosis, nasopharyngitis, constipation, chest pain, anaphylaxis and vomiting. During the first three months of treatment, the incidence of gout flares was higher in patients treated with KRYSTEXXA every two weeks compared to placebo; however, with continued treatment during months four through six, reductions in gout flares were observed in the proportion of patients with gout flare in the KRYSTEXXA every two-week versus placebo-treated groups.
Infusion-related reactions (IRs) occurred in 26 percent, 42 percent and five percent of the every two-week, every four-week and placebo-treated study groups, respectively. Resolution of all IRs began within minutes of slowing or discontinuing the infusion and/or initiating supportive treatment, and all IRs resolved completely.
In a retrospective analysis of IRs, five patients experienced anaphylaxis, including two patients each in the KRYSTEXXA every two-week and every four-week cohorts, and one additional patient assigned every two-week treatment who experienced anaphylaxis during the first infusion. All signs and symptoms resolved completely in these five patients, and three of these patients continued participating in the studies and receiving treatment with KRYSTEXXA.As previously reported, seven deaths occurred between randomization and database closure in the KRYSTEXXA clinical development program; however, none were believed to be drug related. Four deaths occurred in the treatment group and three occurred in the placebo group. Of the four deaths in the treatment groups, two were attributed to cardiac events and occurred in patients with four or more cardiovascular risk factors at baseline. Of the two non-cardiovascular related deaths, one was attributed to renal failure after the patient's voluntary withdrawal from renal dialysis, and the other was attributed to methicillin-resistant Staphylococcus aureus sepsis. ABOUT THE KRYSTEXXA® PIVOTAL STUDIES The two replicate, randomized, six-month, double-blind, placebo-controlled KRYSTEXXA® Phase III trials were conducted in centers in the United States (U.S.), Canada and Mexico between June 2006 and October 2007 and evaluated 212 patients with severe gout, allopurinol intolerance/refractoriness, and serum uric acid concentration > 8.0 mg/dL. Patients were randomly assigned to receive 12 two-week intravenous infusions containing either KRYSTEXXA 8 mg at each infusion every two-weeks or KRYSTEXXA alternating with placebo at successive infusions (every four-week treatment group) or placebo (every two-week placebo group). ABOUT KRYSTEXXA® KRYSTEXXA® (pegloticase) is a PEGylated uric acid specific enzyme for administration by intravenous infusion for the treatment of refractory chronic gout (RCG) in adult patients. KRYSTEXXA became commercially available in the U.S. by prescription on December 1, 2010, and is the only U.S. Food and Drug Administration approved product specifically indicated for the treatment of RCG. KRYSTEXXA is not recommended for the treatment of asymptomatic hyperuricemia. For more information about KRYSTEXXA, please visit: http://www.krystexxa.com/. IMPORTANT SAFETY INFORMATION ABOUT TREATMENT WITH KRYSTEXXA ® KRYSTEXXA is not indicated for the treatment of asymptomatic hyperuricemia. Patients who are at risk of having a condition known as G6PD deficiency should be screened by their physician prior to starting therapy with KRYSTEXXA.