Rasburicase

Elitek is indicated for the initial management of plasma uric acid levels in pediatric and adult patients with leukemia, lymphoma, and solid tumor malignancies who are receiving anticancer therapy expected to result in tumor lysis and subsequent elevation of plasma uric acid. Elitek is a recombinant urate-oxidase indicated for initial management of plasma uric acid levels in pediatric and adult patients with leukemia, lymphoma, and solid tumor malignancies who are receiving anticancer therapy expected to result in tumor lysis and subsequent elevation of plasma uric acid. Limitations of use: Elitek is indicated only for a single course of treatment.

In humans, uric acid is the final step in the catabolic pathway of purines. Rasburicase catalyzes enzymatic oxidation of poorly soluble uric acid into an inactive and more soluble metabolite (allantoin).

Administer at 0.2 mg/kg as an intravenous infusion over 30 minutes daily for up to 5 days. Do not administer as an intravenous bolus. Dosage The recommended dose of Elitek is 0.2 mg/kg as a 30-minute intravenous infusion daily for up to 5 days. Dosing beyond 5 days or administration of more than one course is not recommended. Reconstitution Procedure Elitek must be reconstituted with the diluent provided in the carton. Reconstitute the 1.5 mg vial of Elitek with 1 mL of diluent. Reconstitute the 7.5 mg vial of Elitek with 5 mL of diluent. Mix by swirling gently. Do not shake or vortex. Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Discard solution if particulate matter is visible or product is discolored.

Elitek is contraindicated in patients with a history of anaphylaxis or severe hypersensitivity to rasburicase or in patients with development of hemolytic reactions or methemoglobinemia with rasburicase. Elitek is contraindicated in individuals deficient in glucose-6-phosphate dehydrogenase (G6PD). History of the following reactions to rasburicase: anaphylaxis, severe hypersensitivity, hemolysis, methemoglobinemia. Glucose-6-phosphate dehydrogenase (G6PD) deficiency.

Boxed warning: Hypersensitivity Reactions: Elitek can cause serious and fatal hypersensitivity reactions including anaphylaxis. Immediately and permanently discontinue Elitek if a serious hypersensitivity reaction occurs. Hemolysis: Do not administer Elitek to patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Immediately and permanently discontinue Elitek if hemolysis occurs. Hypersensitivity Reactions Elitek can cause serious and fatal hypersensitivity reactions including anaphylaxis. In clinical studies, anaphylaxis was reported in <1% patients receiving Elitek. This can occur at any time during treatment including the first dose. Signs and symptoms of these reactions include bronchospasm, chest pain and tightness, dyspnea, hypoxia, hypotension, shock, and urticaria.

The following clinically significant adverse reactions are discussed in greater detail in other sections of the prescribing information: Anaphylaxis Hemolysis Methemoglobinemia Most common adverse reactions (incidence ≥20%), when used concomitantly with anticancer therapy are vomiting, nausea, fever, peripheral edema, anxiety, headache, abdominal pain, constipation, diarrhea, hypophosphatemia, pharyngolaryngeal pain, and increased alanine aminotransferase.

Laboratory Test Interference At room temperature, Elitek causes enzymatic degradation of the uric acid in blood/plasma/serum samples potentially resulting in spuriously low plasma uric acid assay readings. The following special sample handling procedure must be followed to avoid ex vivo uric acid degradation. Uric acid must be analyzed in plasma. Blood must be collected into prechilled tubes containing heparin anticoagulant. Immediately immerse plasma samples for uric acid measurement in an ice water bath. Plasma samples must be prepared by centrifugation in a precooled centrifuge (4°C). Finally, the plasma must be maintained in an ice water bath and analyzed for uric acid within four hours of collection.

Do not freeze. The lyophilized drug product and the diluent for reconstitution should be stored at 2°C-8°C (36°F-46°F). Protect from light.