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News from the American Society of Hematology Annual Meeting
This year’s meeting of the American Society of Hematology (ASH), held December 3 to 7, 2010 in Orlando, Florida, featured 13 hours of presentations and 80 pages of abstracts about ITP, plus even more information about other platelet disorders. Some highlights:
- Final Results Reported from 5-year Study of Romiplostim (Nplate)
- Long-term Safety and Efficacy from EXTEND Study of Eltrombopag (Promacta)
- Rituximab Maintenance Treatment: a New Approach
- Insights into Anti-D (Win Rho) Adverse Events
- Drug-induced Thrombocytopenia Antibodies Inhibit Platelet Production
- Increased Microparticles Linked to Thrombosis in ITP
- Studies Reveal New Relationships in Fatigue and ITP
- B-cell Defects Found in ITP Patients
The ASH abstract numbers and titles are listed below the summaries. You can read the abstracts and find other information about the ASH meeting at http://www.hematology.org/Meetings/Annual-Meeting/
After 277 weeks of following up to 292 patients with ITP, with a median time on study of 78 weeks, the results of this long-term study are complete. Almost all of the patients in the study achieved a platelet count greater than 50,000 at least once and more than 50% of people had a platelet count more than 50,000 for 90% of the time.
#68 “Long-Term Efficacy and Safety of Romiplostim Treatment of Adult Patients with Chronic Immune Thrombocytopenia (ITP): Final Report from an Open-Label Extension Study”
See also abstract 3701 “Analysis of Mortality Rates During Romiplostim Clinical Studies of Patients (Pts) with Immune Thrombocytopenia (ITP)”
In this study more than 80% of patients achieved a platelet count of greater than 50,000, independent of other medications or splenectomy status. The most frequent adverse events were headache and upper respiratory problems. However, 5% of patients had a thrombotic event, most frequently deep vein thrombosis, with no association between the event and elevated platelet counts.
#67 “EXTEND Study Update: Safety and Efficacy of Eltrombopag In Adults with Chronic Immune Thrombocytopenia (ITP) From June 2006 to February 2010”
See also abstract 70 “Incidence of Thromboembolic Events Across Eltrombopag Clinical Trials In Chronic Immune Thrombocytopenia (ITP)”
About two-thirds of patients who receive rituximab (Rituxan) for their ITP respond then relapse, but they sometimes achieve another remission with a subsequent dose of rituximab. In this study of 10 patients who relapsed after their first rituximab treatment, 5 with Evan’s syndrome, participants were given the usual 4 weekly doses of rituximab followed by 1 dose of rituximab every 4 months for a total of 6 doses. The study is on-going, but so far the first five people who completed the study are still in remission.
#2523 “Rituximab Maintenance Treatment In Immune Mediated Thrombocytopenia (ITP) Including Evans Syndrome”
In the past a very small percentage of patients treated with anti-D (Win Rho) developed severe depletion of their red blood cells and other complications, including death. Cangene, the company that makes and sells Win Rho, analyzed the medical records of the people who experienced adverse event s after receiving their product and found several conditions that could lead to more severe complications. These are: active viral infections, hematological malignancies, other autoimmune or inflammatory diseases, and people over 65 with other health problems.
#3685 “Potential Identification of High Risk Populations for Acute Hemolytic Reactions Following Rh0 (D) Immune Globulin”
In this study, researchers found that patients with quinine-induced thrombocytopenia had impaired platelet production. Specifically, the megakaryocytes in their bone marrow did not form proplatelets (elongated strands of cytoplasm that turn into platelets) as well as the control subjects. This phenomenon is in addition to the antibody-mediated platelet destruction typically seen in drug-induced thrombocytopenia.
Note: quinine is a common cause of drug-induced thrombocytopenia and is present in some food and drink such as tonic water and bitter melon.
#384 “Proplatelet Production Is Impaired by Drug-Induced Thrombocytopenia Antibodies”
Researchers in Spain measured and tested the clotting potential of microparticles (very small bits cells) in the blood of people with ITP and found that the microparticles in these patients were more prone to form blood clots than the microparticles in the control population. This was also true of those ITP patients who had a splenectomy and were in remission. The clotting potential of microparticles may be helpful in preventing bleeding, but this condition may also make people with ITP more prone to heart attacks, strokes, and clots in their veins than might be expected.
#3707 “Increased Microparticle-Linked Procoagulant Activity In Patients with Primary Immune Thrombocytopenia”
In a quality-of-life study, non-splenectomized patients taking romiplostim (NPlate) completed the same questionnaire every 12 weeks for a year as those receiving other treatments. The results showed the romiplostim patients’ quality-of-life scores improved more than those receiving other treatments, with the exception of fatigue.
In another study, a third of patients with active ITP reporting fatigue experienced day-time sleepiness and 8% felt dizzy upon standing. Patients with other health problems, but without active bleeding, also experienced sleepiness and dizziness associated with fatigue.
#569 “Patient Quality of Life (QOL) In Nonsplenectomized Immune Thrombocytopenia (ITP) Patients Receiving Romiplostim or Medical Standard of Care (SOC)”
#570 “Documentation of Fatigue In Patients with Immune Thrombocytopenic Purpura (ITP) and Its Association with Autonomic Dysfunction”
B-cells are a type of white blood cell that promote the production of antibodies, among other things. In careful examination of the immune system of 4 people with ITP, researchers found that 3 of the 4 subjects had more regulatory B-cells, but the cells didn’t work as well as people without the disease. This variation in B-cells may help explain why some people respond to rituximab (Rituxan), a treatment that suppresses B-cells, and others do not.
#379 “Regulatory B Cell Defects In Patients with Immune Thrombocytopenia (ITP)”
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