Drug for Iron Overload Passes Major Safety Hurdle

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Drug for Iron Overload Passes Major Safety Hurdle, May Benefit Patients with Thalassemia and Other Blood Disorders

Philadelphia, Pa. -- An oral medication that may be helpful for patients with thalassemia and related blood disorders has fewer adverse effects on white blood cells than previously predicted. The drug, deferiprone, may help patients with thalassemia who do not benefit from the conventional treatment for iron overload, a life-threatening complication of their disease. A research team headed by a physician from The Children's Hospital of Philadelphia announced the results of their multicenter study today in the British Journal of Haematology.

Thalassemia, an inherited disease of the blood in which hemoglobin fails to form properly, may be challenging to treat. Depending on its severity, the disease may require regular blood transfusions starting in early childhood and may cause an enlarged spleen, bone weakness and growth problems. The blood transfusions lead to the most serious complication, life-threatening multiple organ damage caused by accumulation of excessive iron. Therefore, patients with iron overload receive frequent treatments with desferrioxamine, which removes iron from the tissues. However, this drug is difficult to administer, because it must be pumped into the skin or bloodstream for an 8-to-12-hour period every night. Many patients do not comply with the arduous regimen, and others are unable to use it because of adverse reactions.

Therefore, for the past 20 years, researchers have been seeking an effective oral medicine for iron overload. The leading candidate has been deferiprone, but previous studies showed the medicine had a serious side effect called agranulocytosis, a sharp reduction in white blood cells. The current study measured the frequency of that side effect in 187 pediatric and adult patients at four sites, one at The Children's Hospital of Philadelphia and the other three at thalassemia centers in Italy. The patients were unable or unwilling to use desferrioxamine.

Patients in the study received weekly blood tests to monitor deferiprone's effects. Agranulocytosis occurred in only one patient, while nine patients had a milder reduction in white blood cells (neutropenia). "The study showed that toxicity to white blood cells is a rare side effect of deferiprone, and is not frequent enough to disqualify the drug as a potential treatment for iron overload," said Alan R. Cohen, M.D., chief of Hematology at The Children's Hospital of Philadelphia and lead author of the study. "Although much research remains to be done, deferiprone might also be used to treat patients with other hemoglobin disorders, such as sickle cell disease, in which regular blood transfusions are often used."

Dr. Cohen added that since the study began, other possible side effects of deferiprone have been suggested, such as liver toxicity, and that further studies need to address such concerns. Like desferrioxamine, deferiprone is an iron chelator--a chemical that binds to excess iron and removes it from the body. "We are not proposing that deferiprone should replace desferrioxamine as a first-line therapy for iron overload," he said. "But it may become an option for patients who do not respond to desferrioxamine or who have severe adverse reactions to that conventional therapy."

The Children's Hospital of Philadelphia, the nation's first children's hospital, is a leader in patient care, education and research. This 373-bed multispecialty hospital provides comprehensive pediatric services, including home care, to children from before birth through age 19. The hospital is second in the United States among all children's hospitals in total research funding from the National Institutes of Health.

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