Rasburicase like other proteins, has the potential to induce allergic responses in humans. Clinical experience with Fasturtec demonstrates that patients should be closely monitored for the onset of allergic-type undesirable effects, especially severe hypersensitivity reactions including anaphylaxis (see Adverse Reactions). If such cases, treatment should immediately and permanently be discontinued and appropriate therapy initiated.
Caution should be used in patients with a history of atopic allergies.
At present, there is insufficient data available on patients being re-treated to recommend multiple-treatment courses. Anti-rasburicase antibodies have been detected in treated patients and healthy volunteers administered rasburicase.
Methaemoglobinaemia has been reported in patients receiving Fasturtec. Fasturtec should immediately and permanently be discontinued in patients having developed methaemoglobinaemia and appropriate measures initiated (see Adverse Reactions).
Haemodialysis has been reported in patients receiving Fasturtec. In such cases, treatment should immediately and permanently be discontinued and appropriate measure initiated (see Adverse Reactions).
Administration of Fasturtec reduces the uric acid levels to below normal levels and by this mechanism reduces the chance of development of renal failure due to precipitation of uric acid crystals in renal tubules as a consequence of hyperuricaemia. Tumour lysis can also result in hyperphosphataemia, hyperkalaemia and hypocalcaemia. Fasturtec is not directly effective in the treatment of these abnormalities. Therefore, patients must be monitored closely.
Fasturtec has not been investigated in patients with hyperuricaemia in the context of myeloproliferative disorders.
To ensure accurate measurement of uric acid plasma level during treatment with Fasturtec, a strict sample handling procedure must be followed (see Intructions on Use/Handling and Disposal under Cautions for Usage).
Effects on the Ability to Drive or Operate Machinery: No studies on the effect on the ability to drive and use machines have been performed.
Impairment of Fertility: There are no data regarding the effect of rasburicase on fertility.
Use in pregnancy: There are no data from the use of rasburicase in pregnant women. Results from animal studies could not be interpreted due to the presence of endogenous urate oxidase in standard animal models. Because teratogenic effects of rasburicase cannot be ruled out, Fasturtec should only be used during pregnancy if strictly necessary. Fasturtec is not recommended in women of childbearing potential not using contraception.
Use in lactation: It is unknown whether rasburicase is excreted in human milk. As a protein, the dose for the infant is expected to be very low. During treatment with Fasturtec, the advantage of breastfeeding should be weighed against the potential risk for the infant.