Anaphylaxis

The safety and efficacy of ELITEK have been established only for a single course of treatment [once daily for 5 days (see DOSAGE AND ADMINISTRATION)].

ELITEK may cause severe allergic reactions including anaphylaxis. Signs and symptoms of these reactions include anaphylactic shock, bronchospasm, chest pain, dyspnea, hypotension and/or urticaria. ELITEK administration should be immediately and permanently discontinued in any patient developing clinical evidence of a serious hypersensitivity reaction (see BOXED WARNINGS, Anaphylaxis and ADVERSE REACTIONS, Immunogenicity).

Hemolysis

ELITEK is contraindicated in patients with G6PD deficiency because hydrogen peroxide is one of the major by-products of the conversion of uric acid to allantoin. In clinical studies, two patients developed severe hemolytic reactions [National Cancer Institute Common Toxicity Criteria³ (NCI CTC) grade 3 and 4] within 2-4 days of the start of ELITEK. G6PD deficiency was subsequently identified in one of these patients. ELITEK administration should be immediately and permanently discontinued in any patient developing hemolysis, and appropriate patient monitoring and support measures initiated (e.g., transfusion support). It is recommended that patients at higher risk for G6PD deficiency (e.g., patients of African or Mediterranean ancestry) be screened prior to starting ELITEK therapy (see BOXED WARNINGS, Hemolysis and CONTRAINDICATIONS).

Methemoglobinemia

In clinical studies, methemoglobinemia has been reported in 2 patients receiving ELITEK. Both patients developed serious hypoxemia requiring intervention with the appropriate medical support measures. It is not known whether patients with deficiency of cytochrome b₅ reductase (formerly known as methemoglobin reductase) or of other enzymes with antioxidant activity are at increased risk for methemoglobinemia or hemolytic anemia. ELITEK administration should be immediately and permanently discontinued in any patient identified as having developed methemoglobinemia, and appropriate monitoring and support measures (e.g., transfusion support, methylene-blue administration) implemented (see BOXED WARNINGS, Methemoglobinemia).

General

Patients on ELITEK should receive intravenous hydration according to standard medical practice for the management of plasma uric acid in patients at risk for tumor lysis syndrome.

Carcinogenesis, Mutagenesis, Impairment of Fertility

Long-term studies in animals to evaluate carcinogenic potential have not been performed.

ELITEK was non-genotoxic in the Ames, unscheduled DNA synthesis, chromosome analysis, mouse lymphoma, and micronucleus tests.

ELITEK did not affect reproductive performance or fertility in male or female rats at doses 8-fold higher than the human dose when corrected for differences in body surface area.

Pregnancy Category C

Animal reproduction studies have not been conducted with ELITEK. It is also not known whether ELITEK can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. ELITEK should be given to a pregnant woman only if clearly needed.

Nursing Mothers

It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants, a decision should be made whether to discontinue nursing or to discontinue ELITEK, taking into account the importance of the drug to the mother.

Pediatric Use

The efficacy and safety of ELITEK was studied in 246 pediatric patients ranging in age from 1 month to 17 years. There were an insufficient number of patients in the 0-6 months age group (n=7) to determine whether they respond differently from older children. These patients were pooled into the <2 years of age group (n=24). Children <2 years of age had a higher mean uric acid AUC_{0-96 hr} than those age 2-17 years (150 ± s.e. 16 mg·hr/dL vs. 108 ± s.e. 4 mg·hr/dL, respectively). In addition, the data suggest that children <2 years of age had a lower rate of success at achieving maintenance uric acid concentration by 48 hours [83% (95% CI of 62 to 95) vs. 93% (95% CI of 89 to 95), respectively]. Children <2 years old also experienced more toxicity. The following adverse events were observed more frequently in children less than 2 years of age compared to those age 2-17 years respectively: vomiting (75% vs. 55%), diarrhea (63% vs. 20%), fever (50% vs. 38%), and rash (38% vs. 10%).

Geriatric Use

Five of the 19 adults among the 265 patients enrolled in clinical studies of ELITEK, were age 65 or greater. Therefore, there are insufficient data to determine whether geriatric subjects, or adults in general, respond differently from pediatric subjects.

Bookmark this page: