- Additional Data Show the Standard Treatment for Sickle Cell Disease is Widely Under-Prescribed in Some Populations -
ATLANTA, Dec. 8 /PRNewswire-USNewswire/ -- New research to be presented at the 49th Annual Meeting of the American Society of Hematology in Atlanta, GA, will provide important insight into the treatment and management of sickle cell disease and thalassemia, both disorders of the red blood cells. Specifically, data will be presented on advancements in iron chelation therapy, treatments necessary for patients who require multiple blood transfusions because of the risk of excess iron. Researchers will also unveil new findings about brain damage in sickle cell patients, a complication of the disorder that can occur as patients age. Additionally, retrospective and prospective trials among Florida Medicaid populations and patients in Nigeria, an area with the highest global burden of sickle cell disease, will show the need for physician education to address the underutilization of hydroxyurea, which is an efficacious treatment associated with a significant reduction in sickle cell complications, hospitalizations, and transfusion requirements by about 50 percent and in mortality by 40 percent. A press conference revealing this new research will take place Saturday, December 8, from 1:30 p.m. to 2:30 p.m.
"Sickle cell disease, once considered a fatal pediatric condition, is now a chronic adult illness. As physicians, we need to better understand how to treat sickle cell patients from childhood through their adult life," said press conference moderator Marilyn Telen, MD, Division Chief of Hematology, Duke University, Durham, NC. "Further, by understanding how to effectively mitigate the consequences of multiple transfusions, particularly iron overload, we can better serve a broad range of patients who suffer from red blood cell disorders."
-- Hydroxyurea, a highly efficacious treatment for sickle cell patients, is underutilized in a Florida Medicaid population [Abstract #79]
Richard Lottenberg, MD, Division of Hematology/Oncology, University of Florida College of Medicine, Gainesville, FL
This retrospective cohort study aimed to determine adoption and utilization of hydroxyurea therapy in sickle cell disease among 2,301 Florida Medicaid-eligible patients over 16 years of age. It found that the prevalence of hydroxyurea use in this Medicaid population is low. Hydroxyurea adoption was determined by the presence of at least one hydroxyurea pharmacy claim and about 17 percent of the patients had at least one pharmacy claim for hydroxyurea. Hydroxyurea users compared to non-hydroxyurea users were more likely to be males, older than 25, with a history of using slow-release opioid medications, or receiving red cell transfusions. A substantial number of patients that met FDA-approved criteria for hydroxyurea did not receive it. The study also found that early therapy drop-out and low adherence rates were common in patients prescribed hydroxyurea. These findings highlight the need to develop programs to enhance physician adoption and prescribing of hydroxyurea, as well as educational materials to increase patient adherence.
-- First-ever evaluation of hydroxyurea use in Nigerian population shows absolute lack of use by physicians in area with highest incidence of sickle cell disease worldwide [Abstract #80]
Zakari Aliyu, MD, MPH, Center for Sickle Cell Disease, Howard University, Washington, DC
This prospective trial included interviews with 206 adult and pediatric sickle cell patients and 10 hematologists, and reviewed data from more than 1,000 patients, all based in Nigeria, about hydroxyurea utilization. The study found that 100 percent of the Nigerian hematologists surveyed reported discomfort with instituting hydroxyurea as a treatment option for sickle cell disease patients. Barriers to hydroxyurea utilization identified by physicians included safety and toxicity profile (100 percent), patient compliance (100 percent), effective follow-up (100 percent), drug availability (100 percent), affordability (100 percent), and concern for reactivation of latent tuberculosis (50 percent), carcinogenesis (100 percent), and teratogenicity (associated with birth defects) (100 percent).
No patient was currently on hydroxyurea treatment and only 5 percent of the patients interviewed had been informed of or were aware of hydroxyurea. Patient-related barriers to hydroxyurea included lack of awareness (95 percent), cost (100 percent), availability (100 percent), need for frequent follow-up (90 percent), risk of infections (98 percent), and pregnancy restrictions and need for concurrent contraceptive use (98 percent).
The authors concluded that the absolute lack of hydroxyurea utilization in a major health-care center in Nigeria, the country with the highest incidence of sickle cell disease in the world with about 150,000 children born with the disease annually, underscores the need for education of local health-care providers as well as patient counseling and education. In addition, clinical studies designed to assess the safety and efficacy of hydroxyurea in unique African settings is needed to facilitate the introduction and utilization of hydroxyurea in Nigeria and other parts of Africa.
-- Cognitive function impaired among sickle cell patients; transfusion trial needed to assess how to mitigate brain damage, especially as patients age [Abstract #428]
Elliott Vichinsky, MD, Children's Hospital and Research Center, Oakland, CA
Many consider brain dysfunction to be the most important and least-studied problem afflicting the aging sickle cell population. About 25 percent of neurologically intact sickle cell pediatric patients have neuropsychological dysfunction -- a deficit in cognitive ability -- and silent central nervous system (CNS) infarction -- death of tissue within the CNS system, including the brain and spinal cord. In children, age is associated with a decline in neuropsychological dysfunction, suggesting adults are at risk for progressive brain injury.
This trial evaluated 138 adults with sickle cell anemia and 37 control subjects with a series of cognitive tests that assessed verbal and nonverbal intelligence, academic achievement, executive functioning, processing speed, attention, and memory. Tests included the Wechsler Adult Intelligence Scale, the Wechsler Memory Scale, the Woodcock-Johnson Tests of Achievement, the Test of Everyday Attention, and others. MRI scans were also evaluated in 82 patients to evaluate brain atrophy and lesions.
The study found that neuropsychological dysfunction and/or undetected brain injury affect the majority of neurologically intact adults with sickle cell anemia, especially in areas of executive functioning, reading, and math fluency. In the study, 32 percent and 39 percent scored below 86 on the Wechsler Adult Intelligence Scale Performance IQ and Processing Speed Index scores, respectively, compared to 15 percent in national norms; 26 percent and 22 percent of patients scored below 86 on the Wechsler Memory Scale Visual Immediate and Immediate Memory scales, respectively, compared to 15 percent in national norms. Controlling for age, gender, and education, patients and controls differed significantly on the Wechsler Adult Intelligence Scale Processing Speed Index score and the Woodcock-Johnson score including reading, math, and following directions. Sub-tests of the Test of Everyday Attention -- in attention and flexibility of thought -- showed significant decrease in performance with age in sickle cell patients, but not in controls.
In 82 patients with MRIs, 63 percent had an abnormal MRI or neuropsychological dysfunction, 38 percent had atrophy and/or ischemic lesions, and 18 percent had ischemic lesions only. Low Performance IQ and Processing Speed Index were significantly associated with ischemic lesions. Adjusting for age and gender, hippocampal volume (the size of the hippocampus, the part of the brain related to memory) in patients was 541.1 L less than controls and cerebrospinal fluid volume in patients was 16 mL greater than controls. These differences are significant.
The level of hemoglobin (the oxygen-carrying molecule in the blood) was an independent predictor of verbal IQ, Performance IQ, Processing Speed Index, math, and executive function. Patients with lower hemoglobin scores had lower IQ scores, and ischemic lesions alone did not account for the extent of the neuropsychological impairment observed. Hemoglobin levels, age, and hippocampal volume were predictive of the neuropsychological dysfunction, suggesting a link between reduced oxygenation, neuronal loss, and cognitive impairment. These data support the importance of future trials on transfusion and improvement of neuropsychological function.
-- Sequential deferiprone-deferoxamine superior to deferiprone monotherapy, the current "gold standard" in patients with thalassemia major [Abstract #575]
Aurelio Maggio, MD, Hospital 'V. Cervello', Palermo, Italy
This five-year, multicenter, randomized trial evaluated two chelating regimens in 140 patients with thalassemia major, a genetic disorder characterized by the underproduction of hemoglobin, the molecule in red blood cells that carries oxygen to all tissues. Chelating agents remove excess iron from the body, a common problem in red blood cell disorders because of the associated blood transfusions. Excess iron can lead to organ damage and heart failure. This trial evaluated deferiprone monotherapy compared with sequential treatment with deferiprone for four days followed by deferoxamine for three days. While deferiprone is an oral drug, deferoxamine is administered via subcutaneous infusion.
The study found that long-term use of sequential deferiprone-deferoxamine treatment was more effective than the "gold standard" treatment of deferiprone alone, with milder and reversible side effects, such as reversible leukocytopenia (low number of white blood cells) and hypertransaminasemia, which was defined as the increase of serum alanine transaminase levels up to two times in comparison to normal values. In addition, after one year of treatment, the deferiprone-deferoxamine group showed greater efficacy in terms of serum ferritin level reduction than the deferoxiamine-only arm of a previous randomized clinical trial in which a comparable cohort of patients were studied.
-- Deferasirox, an oral iron chelator, works as well as deferoxamine, which requires subcutaneous injection, among sickle cell patients; possible implications for improved patient compliance, reducing risk of organ damage [Abstract #3395]
Elliott Vichinsky, MD, Children's Hospital and Research Center, Oakland, CA
This four-year extension trial among 185 patients with sickle cell disease is a follow-up study to a one-year trial that showed that deferasirox and deferoxamine were equally effective at reducing liver iron concentration. In this four-year extension study, all patients stayed on deferasirox (n=132) or were switched to the therapy (n=53). The trial showed that deferasirox demonstrated dose-dependent efficacy in patients with sickle cell disease, with a manageable tolerability profile and no new adverse events reported over a median of 2.1 years of treatment. Because deferoxamine must be delivered via a subcutaneous injection, patients must typically visit their doctor's office or local clinic. Deferasirox is taken orally and therefore may support improved patient compliance, a key factor in avoiding complications of iron overload, including kidney damage.
In addition to sickle cell disease and thalassemia, press briefings will take place at the annual meeting focusing on leukemias, hematologic malignancies, blood clotting and bleeding disorders, and transplantation. The study authors and press program moderator will be available for interviews after the press program or by telephone. For the complete annual meeting schedule and additional information, please visit http://www.hematology.org/meetings/2007.
The American Society of Hematology (http://www.hematology.org) is the world's largest professional society concerned with the causes and treatment of blood disorders. Its mission is to further the understanding, diagnosis, treatment, and prevention of disorders affecting blood, bone marrow, and the immunologic, hemostatic, and vascular systems, by promoting research, clinical care, education, training, and advocacy in hematology.
|SOURCE American Society of Hematology|
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