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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 anti-cancer therapy expected to result in tumor lysis and subsequent elevation of plasma uric acid. ELITEK is indicated only for a single course of treatment.

Managing Elevated Uric Acid Associated with TLS

• Managing Tumor Lysis Syndrome
• Treating Acute Tumor Lysis Syndrome
• Managing Elevated Uric Acid

Managing Tumor Lysis Syndrome

Management of patients with TLS requires a multifaceted approach, and measures should be started 24 to 48 hours before initiating chemotherapy^7,32.

The clinical signs and laboratory indications of TLS should be evaluated prior to starting treatment in order to identify at-risk patients.²² While individual patient management may vary, the cornerstones of current treatment of malignancy-associated TLS include*^4,8,22:

• Hydration
• Diuresis
• Uric acid reduction

Current research suggests that ELITEK (rasburicase) may provide an effective management of elevated uric acid associated with TLS.³³

Important Safety Information for ELITEK (rasburicase)

The following serious adverse reactions occurred with a difference in incidence of greater than or equal to 2% in patients receiving ELITEK compared to patients receiving oral allopurinol in randomized studies (Study 1 and Study 4): pulmonary hemorrhage, respiratory failure, supraventricular arrhythmias, ischemic coronary artery disorders, and abdominal and gastrointestinal infections.

Tumor Lysis Syndrome Management*^7,29,30

*While alkalinization has historically been used to treat elevated uric acid leading to TLS, the advent of agents such as ELITEK (rasburicase) has led researches to suggest a new paradigm in the prevention and management of this disorder.³³ Urine alkalinization has been associated with precipitation of calcium phosphate in the renal tubules, leading to acute renal failure as well as the development of hypocalcemia.^7,22 The benefit of alkalinization has not been unequivocally established for the management of tumor lysis syndrome (TLS).

Treating Acute Tumor Lysis Syndrome

It is important to identify concomitant therapies that may contribute to metabolic abnormalities in patients with tumor lysis syndrome (TLS), such as:

• Oral and IV electrolyte and/or dietary supplements
• Thiazide and potassium-sparing diuretics⁷
• Aspirin
• Probenecid
• ACE inhibitors (associated with increased potassium)
• Nephrotoxic agents (eg, aminoglycosides)
• Radiographic contrast media³⁴

Patients who develop tumor lysis syndrome (TLS) are usually hospitalized so they can be closely monitored. In addition to IV fluid administration, specific therapies may be necessary to reduce uric acid, potassium, and phosphate levels; increase calcium levels; and increase urine flow. The type of treatment used depends on the severity of symptoms and the urgency of the patient's condition. Careful and frequent cardiac monitoring also may be necessary for patients with tumor lysis syndrome (TLS).^7,30

Dialysis may be necessary in the case of severe renal impairment or acute renal failure or to quickly correct metabolic abnormalities. In most cases, patients respond well and normal kidney function is restored. ^8,35 In order to avoid TLS - related elevated uric acid, clinicians should consider assertive prophylactic measures, such as ELITEK (rasburicase), especially in patients at risk for development of TLS.

Elitek Indication

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 anti-cancer therapy expected to result in tumor lysis and subsequent elevation of plasma uric acid. ELITEK is indicated for only a single course of treatment.

Managing Elevated Uric Acid

Once uric acid is produced, uricolytic agents, such as ELITEK (rasburicase), can reduce the amount of circulating uric acid. Uricolytic agents are enzymes (eg, urate oxidase) that catalyze uric acid in the bloodstream to allantoin, a product that is more easily filtered by the kidneys. Urate oxidase is a naturally occurring enzyme found in most species (but not in humans).^1,2,34 Recombinant urate oxidase (ELITEK[rasburicase]) was isolated as a cDNA clone.^2,17,18

ELITEK (rasburicase) is the first recombinant uricolytic agent approved in the U.S.^1,23

ELITEK (rasburicase) catabolizes existing uric acid into allantoin^1,23,24

• Allantoin is 5-10 times more soluble than uric acid^23,24
• With ELITEK, normal uric acid levels are achieved 4 hours after the 1st dose^1,23

Another option for managing uric acid is allopurinol, a xanthine analog, which reduces the formation of new uric acid and has no effect on existing uric acid.³

Important Safety Information for ELITEK (rasburicase)

Among the 347 (265 pediatric; 82 adult) patients for whom all adverse reactions regardless of severity were assessed in Studies 1, 2 and 3, as well as an uncontrolled safety trial, the most frequently observed adverse reactions (incidence ≥10%) were vomiting (50%), fever (46%), nausea (27%), headache (26%), abdominal pain (20%), constipation (20%), diarrhea (20%), mucositis (15%), and rash (13%).

Effect of ELITEK (rasburicase) on Purine Catabolism¹

Anaphylaxis: ELITEK can cause severe hypersensitivity reactions including anaphylaxis. Immediately and permanently discontinue ELITEK in patients who experience a serious hypersensitivity reaction.

Hemolysis: Do not administer ELITEK to patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Immediately and permanently discontinue ELITEK in patients developing hemolysis. Screen patients at higher risk for G6PD deficiency (e.g., patients of African or Mediterranean ancestry) prior to starting ELITEK.

Methemoglobinemia: ELITEK can result in methemoglobinemia in some patients. Immediately and permanently discontinue ELITEK in patients developing methemoglobinemia.

Interference with Uric Acid Measurements: ELITEK enzymatically degrades uric acid in blood samples left at room temperature. Collect blood samples in pre-chilled tubes containing heparin and immediately immerse and maintain sample in an ice water bath. Assay plasma samples within 4 hours of collection.