Report from SCMR: MR travels a long way to test blood disease treatment

February 6, 2006

In a laborious clinical trial that involved hauling a mobile MR scanner over land and sea to the Mediterranean island of Sardinia, British researchers used T2* imaging to confirm the value of a new drug treatment for Β-thalassemia, a genetic blood disorder.

In a laborious clinical trial that involved hauling a mobile MR scanner over land and sea to the Mediterranean island of Sardinia, British researchers used T2* imaging to confirm the value of a new drug treatment for Β-thalassemia, a genetic blood disorder.

Although rare among northern Europeans, Β-thalassemia affects 60,000 births annually worldwide. It is common in some Asian and Mediterranean populations. About 7% of Sardinians carry the Β-thalassemia gene.

The condition results in abnormal hemoglobin and anemia and dictates lifelong treatment with blood transfusions that can lead to myocardial iron loading, dilated cardiomyopathy, and death.

Administration of the drug deferoxamine, the preferred treatment against iron loading, is cumbersome, requiring subcutaneous infusion for 12 hours up to seven days per week. Even with treatment, two-thirds of patients have myocardial iron loading.

In the U.K., only half of all Β-thalassemia patients live longer than age 35, said Dr. Mark A. Tanner, a researcher in the cardiac MR unit of Royal Brompton Hospital in London. Tanner and colleagues, including Royal Brompton CMR director Dr. Dudley Pennell, determined with the help of cardiac MRI that combination therapy involving deferoxamine and deferiprone, another iron chelator, is a better option.

Their research took a mobile 1.5T Siemens scanner for three round trips from London over the English Channel, French and Italian Alps, and the Tyrrhenian Sea to Cagliari, Sardinia. Working with the hematology department of the University of Cagliari, the researchers randomized 65 Β-thalassemia patients into two groups: One received deferoxamine and deferiprone, the other deferoxamine and a placebo. T2* cine imaging was performed before the start of the trial and after six and 12 months.

Tanner presented final results in January at the Society for Cardiovascular Magnetic Resonance meeting in Miami. He found a 40% increase in T2* values representing a statistically significant drop in myocardial iron among patients who received the combined deferoxamine/deferiprone treatment for 12 months. With the help of T2* MRI measurement, similar improvements in iron loading were also seen in the liver. T2* increases in the placebo-treated group were much smaller.

The results suggest that combined deferoxamine/deferiprone therapy will reduce the likelihood of cardiac iron loading and the threat of lethal complications, according to Tanner.

"I would suggest that combined therapy should be considered in all patients who fail to achieve adequate iron load status on deferoximine alone," he said.

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