A
tiny pill may have helped solve one big problem with chronic blood transfusions.
Despite best efforts to make the nation’s blood supply safe, physicians worry about infections and other problems in children who receive regular blood transfusions.
“We have done two studies now involving transfusions, and fortunately, we have not had any serious consequences in the short term: no infections, no serious complications,” said Dr. Robert J. Adams, MCG neurologist and stroke specialist.
The main consequence they have seen is iron overload, which left untreated can seriously damage the heart, liver and other organs.
“If you give one unit of blood, you are giving 250 milligrams of iron,” said Dr. Abdullah Kutlar, hematologist/oncologist and director of MCG’s Sickle Cell Center. “Considering the fact that in many cases you do this repeatedly, you are adding a significant amount of iron.”
The body doesn’t have a mechanism to excrete iron. A healthy person typically won’t absorb too much, so iron supplements, for example, generally aren’t a problem. But patients regularly exposed to large amounts of excess iron can begin to retain more.
The cumulative effect can be significant for sickle cell patients and even worse for people with thalassemia, a condition characterized by dangerously low hemoglobin levels, necessitating transfusions every few weeks, said Dr. Kutlar.
Until
very recently, the only treatment for iron overload was a five-night-per-week
infusion of the drug desferoxamine under the skin. Desferoxamine binds to iron,
changing it into a soluble form that can be excreted by the body. “It’s an
effective drug, but compliance has been notoriously poor for obvious reasons,”
said Dr. Kutlar. “Children don’t want to take it; even adults don’t like the
regimen.”
In November, the Food and Drug Administration approved a drug that works the same way but comes in a tablet taken daily dissolved in liquid. MCG participated in phase-two clinical trials of the new chelating agent, deferasirox, for transfusion-related iron overload and last summer began a phase-three trial. But before that trial was complete, the FDA approved its use for transfusion-related iron overload in patients age 2 and older.
“This takes care of one of the most significant side effects of long-term transfusion,” Dr. Kutlar said.
But that’s not the end of the story. One of many goals is to further define who gets ongoing transfusions to further reduce the potential for problems such as transfusion-related infections no pill can fix.
Dr. Kutlar is looking at genetic variations in Dr. Adams’ study participants for some answers.
“If you had a way to tease out who will revert to low risk and stay there vs. those who will require longer transfusions, that would be a great day,” he said.
Toni Baker