Sickle cell drug changes lives

June 27, 2011

A national study of the oral medication hydroxyurea shows it is safe for use in children as young as 9 months and significantly reduces pain and other complications of sickle cell anemia even in very young children. Hydroxyurea is already recommended to prevent complications of this common inherited blood disorder in school-aged children and adults.

One family positively affected by the study is that of Kaelyn Sanabria, 5. She endured multiple sickle cell disease-induced pain crises before being placed on the drug. But since she has had hydroxyurea prescribed to her by physicians in the Pediatric Sickle Cell Program at Children's Medical Center Dallas, she has not had the severe complications commonly associated with the diagnosis.

"Since she has been on hydroxyurea, she's had maybe one pain crisis every six months as opposed to one or two a month when she wasn't on the drug," said Kaelyn's mother, Kim Rachal of Lancaster, Texas. "And, she's had only one blood transfusion in her life."

In people born with sickle cell anemia, the bone marrow produces rigid, sickle-shaped red blood cells. These cells may clump together and block small blood vessels in the body, causing pain, organ damage, stroke and premature death. Sickle cell disease commonly causes painful crises so severe that patients require hospitalization for medications like morphine. Sickle cell also can lead to chest syndrome — a unique complication of pulmonary infarction and infection that only occurs in the disease — and the need for blood transfusions.

National BABY HUG hydroxyurea study at Children's

Kaelyn was part of a national clinical study at Children's, its academic affiliate — UT Southwestern Medical Center — and 13 other academic medical centers across the country that examined if daily use of hydroxyurea could prevent early organ damage in very young children with sickle cell anemia. The study, known as BABY HUG, found that the drug is safe and significantly reduces pain and other complications of the disease in children as young as 9 months. Until the study, researchers were uncertain whether the drug could also help babies. The results of the study, which enrolled patients from October 2003 to September 2007, appear online and in the May 14 issue of the journal The Lancet.

"We've offered hydroxyurea in the Children's Pediatric Sickle Cell Program since 1992 to severely involved patients with frequent or severe complications down to age 3. On the basis of the BABY HUG study's findings, Children's has made a conscious decision to now offer hydroxyurea to all sickle cell patients in the first year of life," said study co-author Dr. Zora Rogers. Dr. Rogers was the local principal investigator for BABY HUG and is national chair of the BABY HUG Follow-Up Study. She is the clinical director of the general hematology and bone marrow failure program in the Children's Center for Cancer and Blood Disorders and a Professor of Pediatrics at UT Southwestern.

"This medication reduces painful crises, the major problem patients with sickle cell disease face, as well as the problems doctors fear, which include chest syndrome," Dr. Rogers said. "The study also showed a trend of reducing organ damage in the spleen, but the study sample was too small to prove organ protection with hydroxyurea."

Study results likely to affect treatment of young children

The study findings likely will affect how all medical professionals worldwide treat very young children with sickle cell disease regardless of the disease severity or clinical symptoms, Dr. Rogers said.

"We found a decrease in clinical events among trial participants who received hydroxyurea," Dr. Rogers said. "Physicians used to offer hydroxyurea as secondary prevention of sickle cell disease crises, but with these findings, it could become the primary preventative measure." She stressed that the drug is only effective as a preventative measure. "This is not a therapy for when a crisis occurs," Dr. Rogers said. "Patients may still experience painful crises, but the events are much less frequent and severe."

Due to his sister's good response to the medication, Kaelyn's 2-year-old brother, Roman Sanabria, is also taking hydroxyurea prescribed to him by the Pediatric Sickle Cell Program at Children's. Since he has been taking the medication he also hasn't had any pain crises, his mom said, and he's yet to need a blood transfusion.

Said Kim of the medication: "I would definitely recommend hydroxyurea for children with sickle cell disease. I've seen that it really works in both children. The difference is they don't get sick as much with pain crises, chest syndrome, and dactylitis, which is swelling of the hands and feet. I see a total difference in their health now as opposed to before they started using the drug."

The Children's Pediatric Sickle Cell Disease Program

Children's sees approximately 60-65 new children every year for the disease, which is detected by state newborn screening, and is the largest sickle cell disease treatment and research center in the region, caring for more than 650 active patients younger than 18. Approximately 100,000 Americans have the disease.
If you are the family of a child with sickle cell disease and wish to learn more about hydroxyurea or the Children's Pediatric Sickle Cell Disease Program, please call 214-456-6102.