For doctors

What is it?

Fasturtec is a medicine that contains the active substance rasburicase. It is available as a powder and solvent that are made up into a solution for infusion (drip into a vein).

What is it used for?

Fasturtec is used to treat and prevent acute (sudden) hyperuricaemia (increased levels of uric acid in the blood), in order to prevent kidney failure. Fasturtec is used in patients with haematological malignancies (blood cancers) who are at risk of a rapid tumour lysis (breakdown) or shrinkage at the start of chemotherapy (medicines to treat cancer).
The medicine can only be obtained with a prescription.

How is it used?

Fasturtec treatment should be supervised by a doctor who has been trained in the chemotherapy of haematological malignancies. Fasturtec is given before or at the start of chemotherapy. The recommended dose is 0.20 mg per kilogram body weight in both children and adults, given as a daily infusion for up to seven days. The duration of treatment is adjusted depending on the patient’s uricaemia (blood levels of uric acid) and the doctor’s judgment. The infusion should last 30 minutes.

How does it work?

When patients with blood cancers start chemotherapy, they are at risk of developing hyperuricaemia. This is because the chemotherapy destroys the tumour cells, breaking down the genetic material in the cells, and leading to a sharp increase in the levels of uric acid in the blood. The body cannot get rid of too much uric acid, so it can accumulate in the kidneys, causing them to fail (stop working). The active substance in Fasturtec, rasburicase, is an enzyme called urate oxidase, which is able to transform uric acid into another chemical called allantoin. Allantoin can easily be excreted by the kidneys in the urine. The enzyme was originally extracted from a fungus, but in Fasturtec it is produced by a method known as ‘recombinant DNA technology’: it is made by a yeast that has received a gene (DNA) that makes it able to produce urate oxidase.

How has it been studied?

Fasturtec has been studied in four studies involving a total of 372 patients. Two studies were designed to define the best dose to use. Fasturtec was only compared with another treatment (allopurinol, the standard treatment for reducing uric acid levels) in one of the studies, which included 52 patients. In this study, the main measure of effectiveness was the amount of uric acid in the blood, measured over 96 hours.

What benefits has it shown during the studies?

The dose-finding studies showed that, after 48 hours, Fasturtec at a dose of 0.20 mg/kg reduced the uric acid levels to normal in 95% of patients. In the comparative study, Fasturtec was more effective than allopurinol: over the first 96 hours after treatment, patients treated with Fasturtec had a lower average blood level of uric acid than the patients treated with allopurinol (128.1 and 328.5 mg.h/dl, respectively).

What is the risk associated?

The most common side effects with Fasturtec (seen in between 1 and 10 patients in 100) are allergic reactions (mainly rashes and hives) and high fever. Patients should be closely monitored for allergic reactions during treatment. For the full list of all side effects reported with Fasturtec, see the Package Leaflet.
Fasturtec should not be used in patients who are hypersensitive (allergic) to rasburicase or any of the other ingredients. Fasturtec must not be used in patients with a deficiency in (low levels of) glucose-6-phosphate dehydrogenase (G6PD) or other metabolic disorders known to cause haemolytic anaemia (low red blood cell counts caused by the cells being destroyed too soon).

Why has it been approved?

The Committee for Medicinal Products for Human Use (CHMP) decided that Fasturtec’s benefits are greater than its risks for the treatment and prophylaxis of acute hyperuricaemia, in order to prevent acute renal failure, in patients with haematological malignancy with a high tumour burden and at risk of a rapid tumour lysis or shrinkage at initiation of chemotherapy. The Committee recommended that Fasturtec be given marketing authorisation.

Further information

The European Commission granted a marketing authorisation valid throughout the European Union for Fasturtec to sanofi-aventis on 23 February 2001. The marketing authorisation was renewed on 23 February 2006.

Name

Fasturtec1.5 mg/ml powder and solvent for concentrate for
solution for infusion

Composition

After reconstitution, 1 ml of Fasturtec concentrate contains 1.5 mg rasburicase.

Fasturtec is a recombinant urate-oxidase enzyme produced by genetically modified Saccharomyces cerevisiae strain. Rasburicase is a tetrameric protein with identical subunits of a molecular mass of about 34 kDa.

1 mg corresponds to 18.2 EAU*.

*One enzyme activity unit (EAU) corresponds to the enzyme activity that converts 1 µmol of uric acid into allantoin per minute under the operating conditions described: +30 °C ± 1 °C TEA pH 8.9 buffer.

For a full list of excipients, see section 6.1.

Pharmaceutical Form

Powder and solvent for concentrate for solution for infusion.

The powder is an entire or broken white to off white pellet.
The solvent is a colourless and clear liquid.