Warnings and Precautions:
- Anaphylaxis and infusion reactions have been reported to occur during and after administration of KRYSTEXXA. KRYSTEXXA should be administered in healthcare settings and by healthcare providers prepared to manage anaphylaxis. Patients should be pre-medicated with antihistamines and corticosteroids. Patients should be closely monitored for an appropriate period of time for anaphylaxis after administration of KRYSTEXXA.
- Infusion reactions which occurred in some patients treated with KRYSTEXXA. The risk of an infusion reaction is higher in patients who have lost therapeutic response. Because the risk of infusion reactions is higher in patients who lose therapeutic response to KRYSTEXXA, monitor serum uric acid before each infusion and discontinue treatment if levels rise above 6mg/dL, particularly when two consecutive levels above 6 mg/dL are observed.
- An increase in gout flares was seen in some patients treated with KRYSTEXXA. Gout flare prophylaxis with a non-steroidal anti-inflammatory drug (NSAID) or colchicine is recommended starting at least 1 week before initiation of KRYSTEXXA therapy and lasting at least 6 months, unless medically contraindicated or not tolerated.
KRYSTEXXA has not been formally studied in patients with congestive heart failure, but some patients in clinical trials experienced exacerbation. Exercise caution when using KRYSTEXXA in patients who have congestive heart failure and monitor patients closely following infusion.
Patients receiving re-treatment may be at increased risk for anaphylaxis and infusion reactions and should be monitored carefully.
In addition, the European Summary of Product Characteristics (SmPC) includes two other special warnings and precautions for use.
- If haemolysis and/or methemoglobinemia occur in patients receiving KRYSTEXXA, treatment should be immediately and permanently discontinued and appropriate measures initiated.
- Patients over 100 kg body weight may have higher titers of anti-pegloticase antibodies and infusion-related reactions showed a tendency to occur in a greater proportion of patients in this weight group.