An orally active iron chelator, deferiprone (Ferriprox), has been approved by the European Commission for treating iron overload in patients with thalassaemia major.
The manufacturer, Apotex, a Canadian company, hopes to launch deferiprone in Europe in January. The company says that the drug is licensed for patients in whom therapy with desferrioxamine injection is contraindicated, or for those who present with serious toxicity from desferrioxamine therapy.
Life-long blood transfusions, which are required every two to four weeks to treat the severe anaemia associated with thalassaemia major, induce iron toxicity in the body. If the iron overload is not treated, hormone complications and liver and heart damage occur.
Up to now, desferrioxamine injection has been the only iron chelator approved for use in thalassaemia. This drug, which is chemically unrelated to deferiprone, must be given four to seven times a week, depending on iron overload, using an infusion pump for eight to 12 hours per night, or by daily intramuscular injections.
Commenting on the approval of deferiprone, Dr Michael Spino (senior vice president, scientific affairs, Apotex) said: "Deferiprone has been thoroughly tested in thalassaemic patients in Europe and North America. The results from clinical studies have demonstrated this drug to be a safe and effective second line therapy." Deferiprone has been approved at doses of 75-100mg/kg/day, in three divided doses. It has been licensed as a second line therapy because agranulocytosis may develop in a small number of patients, says Apotex. Weekly monitoring of neutrophil count is recommended in order to reduce the risk of serious infection.
According to a recent review in Drugs (1999:58;553), although few long term comparative data are available, deferiprone at the recommended dose of 75mg/kg/day appears to be less effective than desferrioxamine.
Deferiprone was first discovered in 1980 in Professor Robert Hider's laboratory at Essex university.
Speaking to The Journal on September 9, Professor Hider, who is now head of the school of health and life sciences and professor of medicinal chemistry at King's College London, said that deferiprone was a "stop gap, oral chelator." Deferiprone was "metabolised very quickly," which was one of the main reasons for its side effects, he said.
"We are currently working with Apotex to develop a new compound," said Professor Hider. Three lead compounds were being worked on which were "much more effective than deferiprone" and the ability to use a lower dose would cause fewer side effects, he said.