Bleeding Manifestations and Management of Children with Persistent and Chronic Immune Thrombocytopenia (ITP): Data From the Intercontinental Cooperative ITP Study Group.

Abstract Abstract 1315 Poster Board I-339 ITP during childhood is generally characterized by acute onset of thrombocytopenia and bleeding in an otherwise well child. While the platelet count has traditionally been viewed as a marker of disease severity, additional patient characteristics such as bleeding severity have not been well defined. The Intercontinental Cooperative ITP Study Group (ICIS) Registry II was designed to characterize the location, frequency, timing, and severity of bleeding in children with ITP (Blood, 2008;112: 4003-8). We report here data from Registry II with a focus on bleeding symptoms reported at 6 and 12 months. Patients enrolled on Registry II had research visits at diagnosis, and 28 days, 6 months, 12 months, and 24 months following diagnosis. Bleeding manifestations were retrospectively recorded at 6 and 12 months capturing all sites of bleeding (e.g skin, epistaxis, and gastrointestinal) since the last research visit. Of the 1318 children enrolled at diagnosis, 891 were evaluated at 6 months and 718 at 12 months. Mean platelet counts were 198 × 109/l (s.d. 130) and 195 × 109/l (s.d.122) at 6 and 12 months respectively. At 6 months 29% (261/891) of patients still had a platelet count <100 × 109/l; of these 45% (118/261) were <30 × 109/l. At 12 months these values were 28% (203/718) and 40% (82/203) respectively. Number of bleeding sites reported since the last research visit at 6 months and 12 months are outlined in Table 1. There were no reports of intracranial hemorrhage (ICH) or fatal hemorrhage. The most common bleeding site reported at both 6 and 12 months was skin, followed by epistaxis. 4 children with a platelet count <30 × 109/l at both 6 and 12 months were reported as having undergone splenectomy. Red cell transfusions were infrequent (3 reported) and administered only in children with bleeding from ≥ 3 sites. The percentage of patients with a platelet count <30 × 109/l who received platelet count enhancing therapy (including platelet transfusions) is outlined in Table 2. Table 1 Number of bleeding sites reported since last research visit at 6 and 12 months 6 month visit 12 month visit Number of sites Platelet count <100 × 109/l (n= 261) Platelet count <30 × 109/l (n= 118) Platelet count <100 × 109/l (n= 203) Platelet count <30 × 109/l (n= 82) None 60 (23%) 10 (9%) 74 (36%) 16 (19%) 1 110 (42%) 44 (37%) 82 (40%) 33 (40%) 2 61 (23%) 39 (33%) 32 (16%) 21 (26%) 33 30 (12%) 25 (21%) 15 (7%) 12 (15%) Table 2 Patients with platelet count <30 × 109/l reported as having received platelet count enhancing therapy Number of bleeding sites reported between research visits Treatment reported between 28 days and 6 months (n = 118) Treatment reported between 6 and 12 months (n = 82) None 1/10 (10%) 4/16 (8%) 1 29/44 (66%) 19/33 (58%) 32 58/64 (91%) 26/33 (78%) In summary, approximately 30% of children with ITP enrolled on ICIS Registry II remain thrombocytopenic 6 and 12 months later, many still having a platelet count <30 × 109/l, a threshold value sometimes used to determine drug treatment and enrollment in prospective intervention studies. This cut-off may be appropriate since bleeding was more common when the platelet count was <30 × 109/l. However, even below this threshold life-threatening hemorrhage was uncommon, few patients required packed red blood cell transfusions, and approximately half the patients reported no more than one site of bleeding. Treatment was infrequently used in patients in this group if they had no bleeding, and platelet enhancing therapy was often employed if more bleeding sites were involved. These data suggest a trend towards reserving treatment for patients with more severe bleeding manifestations rather than because of a specific platelet count. Disclosures Buchanan: AMG 531: Research Funding. Bolton-Maggs:Baxter: Travel support to meetings; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; United Kingdom Immune Thrombocytopenic Pupura Support Association: Research Funding; Glaxo Smith Kline: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Blanchette:AMG 531: Membership on an entity's Board of Directors or advisory committees. Kuehne:F. Hoffman-La Roche Ltd: Research Funding; Amgen: Research Funding.

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Rate of Prolonged Response after Stopping Thrombopoietin-Receptor Agonists Treatment in Primary Immune Thrombocytopenia (ITP): Results from a Nationwide Prospective Multicenter Interventional Study (STOPAGO)

Blood ◽

10.1182/blood-2021-152767 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 583-583

Author(s):

Matthieu Mahevas ◽

Stephanie Guillet ◽

Jean-Francois Viallard ◽

Delphine Gobert ◽

Marion Malphettes ◽

...

Keyword(s):

Platelet Count ◽

Board Of Directors ◽

Research Funding ◽

Complete Response ◽

Severe Bleeding ◽

Bleeding Events ◽

Advisory Committees ◽

Overall Response ◽

Thrombopoietin Receptor ◽

Prolonged Response

Abstract Background: Thrombopoietin receptor agonists(TPO-RAs) have been thought to play only a supporting role in ITP management. Several retrospective studies and a recent prospective study have reported unexpected cases of durable remission after TPO-RAs discontinuation in adult ITP in up to 30%. However, newly diagnosed ITP cases for which spontaneous remission may occur have been included in most of these studies. Thus, the main purpose of this study was to determine the proportion of patients with either persistent or chronic phase and no recent exposure to any potentially curative therapy (i.e., splenectomy or rituximab) achieving long-term remission off-treatment at 24 and 52 months after at least 3 months of TPO-RAs exposure with a complete response (CR). Patients/methods: We conducted a nationwide prospective multicenter interventional study (NCT03119974). Inclusion criteria were: 1) Patients aged > 18 years, with persistent or chronic primary ITP, 2) A stable CR defined by a platelet count > 100 x 10 9/L for more than 2 months on TPO-RA therapy, 3) Treatment with TPO-RA for at least 3 months. Main exclusion criteria were: 1) Anticoagulation or anti-platelet treatment, 2) Previous failure of TPO-RA discontinuation, 3) Concomitant treatment with corticosteroids ± intravenous immunoglobulin 4) Rituximab or splenectomy within the 2 months preceding or after TPO-RA initiation. After inclusion, the decrease and wean of either eltrombopag or romiplostim was initiated according to a standardized protocol (respectively tapering of 25 mg every 2 weeks or tapering of 1 ug/kg every week). In any case TPO-RAs had to be stopped at week 10. In case of relapse after TPO-RA discontinuation, the decision to start a new therapy was left at every investigator discretion. The primary endpoint was the proportion of patients achieving an overall response (CR + R) at week 24 (6 months) after TPO-RAs discontinuation. Secondary outcomes were overall response rate over the study period (W52), bleeding events, and to identify predictive factors, for overall prolonged response (W24 and W52). Results: Forty-nine patients (30 females, 61%), with persistent (n=2) or chronic (n=47, 96%) chronic ITP, with a median age of 58.5 years IQR (41 to 73) fulfilling the eligibility criteria were included over 2 year-period in 22 centers from the French reference network for adult' ITP. Forty patients received eltrombopag and 9 romiplostim at the time of inclusion. One patient was excluded since she was diagnosed pregnant one day after inclusion. In intention to treat 27/48 (56.2%; 95% CI, 29.5 to 58.8) patients achieved the primary-endpoint and maintained an overall response at week 24 after TPO-RAS discontinuation with a complete response for 15/27 (55%). During the full follow-up period of 52 weeks after TPO-RAs discontinuation, overall response was observed in 25/48 (52.1%; 95% CI, 37.2 to 66.2) patients (Figure 1). Bleeding events occurred in 13/21 (61.9%) and 15/23 (65.2%) patients relapsing respectively at 24 and 52 months with a median platelet count of 31´10 9/L(26 to 39) and 31 ´10 9/L(23 to 39). No severe bleeding episode (French bleeding score > 8) occurred. Median time of relapse after tapering initiation was 8 weeks. Among 21 patients with a relapse (<30 x 10 9/L) before week 24, 13 patients were re-challenged with the same TPO-RA with a CR achieved with a median time of 2 weeks (2-4). In univariate analysis, age, ITP duration, TPO-RA duration before discontinuation, platelet count at inclusion and TPO-RAs drug class were not predictive of sustained response. Conclusion: These results showed an unexpectedly high rate of sustained off-treatment remission after TPO-RAs discontinuation in chronic ITP among patients who initially achieve a stable CR. When they occur, relapses are mainly observed within the first weeks after discontinuation, very rarely afterwards and with no severe bleeding. While no predictive factor of lasting remission has been yet identified, our study strongly supports a progressive tapering of the dose of TPO-RAs in patients achieving a stable CR on treatment. Figure 1: Relapse at 52 weeks after TPO-RAs discontinuation Figure 1 Figure 1. Disclosures Mahevas: GSK: Research Funding; Amgen: Honoraria. Viallard: Novartis: Consultancy; Grifols: Consultancy; LFB: Consultancy; Amgen: Consultancy. Moulis: Amgen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Argenx: Membership on an entity's Board of Directors or advisory committees; Grifols: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sobi: Membership on an entity's Board of Directors or advisory committees. Terriou: Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Michel: Novartis: Consultancy; Amgen: Consultancy; UCB: Honoraria; Argenx: Honoraria; Rigel: Honoraria; Alexion: Honoraria. Godeau: Sobi: Consultancy; Novartis: Consultancy; Amgen: Consultancy; Grifols: Consultancy.

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Assessing the Safety of Various VWF Regimens in Patients with Clinically Severe VWD: A Natural History Study

Blood ◽

10.1182/blood-2019-128318 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 1132-1132

Author(s):

Robert F. Sidonio ◽

Angela C. Weyand ◽

Dunlei Cheng ◽

Crystal Watson

Keyword(s):

Board Of Directors ◽

Study Design ◽

Real World ◽

Research Funding ◽

Laboratory Data ◽

Severe Bleeding ◽

Advisory Committees ◽

On Demand ◽

Type 3 ◽

Von Willebrand

Background: Von Willebrand disease (VWD) is the most common inherited bleeding disorder in humans affecting up to 1% of the population, while symptomatic prevalence is likely closer to 0.1%. A deficiency of von Willebrand factor (VWF) can be quantitative (type 1 or type 3) or qualitative (type 2) and lead to a bleeding diathesis of variable intensity roughly correlating with functional activity. Diagnosis can be challenging due to variable penetrance and large influence of multiple pre-analytic variables and a wide testing coefficient of variation. Treatment for VWD is focused on replacement of defective or deficient VWF with a plasma-derived or recombinant VWF-containing product, release and elevation of endogenous stores of VWF with Desmopressin (DDAVP), or prevention of premature fibrinolysis with an antifibrinolytic, such as aminocaproic acid. Although there is relative consensus on the management of mild VWD, there is scarce literature about the optimal treatment of patients with severe disease, especially in regard to factor replacement. Real World evidence for the use of primary (prior to significant bleeding) or secondary (following development of significant bleeding) prophylaxis is lacking with the majority of studies relying heavily on retrospective data. Additionally, ongoing VWD prophylaxis studies typically only allow participants to enroll if they previously have not been on prophylaxis, limiting our ability to learn about this growing population of patients. Study Design and Methods: Approximately 1,900 VWD patients were identified in the ATHNdataset with a VWF:Ag or VWF:RCo of ≤ 30%, with ~170 of these on prophylaxis. This group, in addition to those VWD patients with clinically significant bleeding and ≤ 40% of normal VWF:Ag or VWF:RCo, provide a potential unmet opportunity to examine prophylaxis and treatment patterns. Furthermore, a standardized laboratory assessment (including a standardized diagnostic battery, genetic evaluation of VWF gene, and inhibitor testing) will provide significant enrichment of the ATHNdataset by fully characterizing patients that are highly likely to utilize factor concentrates. Inclusion criteria are patients with severe VWD defined as type 3 VWD, or VWF:RCo, VWF:GP1bM or VWF:Ag≤ 30%, patients with clinically severe VWD as defined by VWF:Rco, VWF:GP1bM or VWF:Ag ≤ 40% with severe bleeding phenotype requiring recurrent use of factor concentrates, and co-enrollment in the ATHNdataset. Patients with platelet-type or acquired VWD are excluded. The primary objective is to assess the safety of various VWF regimens for different indications (on-demand, surgery, and prophylaxis) in adult and pediatric patients with clinically severe VWD. Safety is measured by the number of reported events as defined by the European Haemophilia Safety Surveillance (EUHASS) program. Secondary objectives are to enrich and analyze data from clinically severe congenital VWD patients by collecting laboratory data; to establish sub-studies for patients who are treated with VWF products on demand or who have started on or switched to a particular VWF containing product; to evaluate the use of factor replacement as prophylaxis in a cohort of severe VWD participants over 6 month time periods; to describe bleeding events, changes in overall bleeding, and annualized bleed rate as measured by the International Society on Thrombosis and Haemostasis (ISTH) Bleeding Assessment Tool (BAT) and if applicable the Pictorial Bleed Assessment Chart (PBAC); and to describe real-world effectiveness of VWD treatment as measured by health care utilization and quality of life measures (PROMIS® and V-WIQ questionnaires). Descriptive statistics will be calculated to analyze the primary and secondary outcomes. For each categorical variable, its frequency and percentage will be reported. In terms of a continuous measurement, its mean, median, standard deviation, interquartile range, minimum, and maximum values will be disclosed. The study will attempt to enroll a target number of at least 50 participants who are receiving VONVENDI but will not mandate the use of VONVENDI. More study design details are outlined in Table 1. Disclosures Sidonio: Genetech: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda-Shire: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bioverativ: Membership on an entity's Board of Directors or advisory committees, Research Funding; Octapharma: Membership on an entity's Board of Directors or advisory committees, Research Funding; Grifols: Membership on an entity's Board of Directors or advisory committees, Research Funding; Biomarin: Membership on an entity's Board of Directors or advisory committees; Uniqure: Membership on an entity's Board of Directors or advisory committees; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees; Kedrion: Research Funding.

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Severe Bleeding Events in Hemophilia Α Patients Receiving Emicizumab Prophylaxis

Blood ◽

10.1182/blood-2019-126659 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 1126-1126

Author(s):

Karen L. Zimowski ◽

Glaivy M. Batsuli ◽

Paulette Bryant ◽

Jenny McDaniel ◽

Kelly Tickle ◽

...

Keyword(s):

Board Of Directors ◽

Research Funding ◽

Hemophilia A ◽

Severe Bleeding ◽

Severe Hemophilia ◽

Bleeding Events ◽

Advisory Committees ◽

Acute Bleeding ◽

Fviii Activity ◽

Bleeding Episodes

Introduction : Emicizumab is a novel humanized bispecific antibody that mimics the function of activated coagulation factor VIII (fVIII). It has significantly changed the management of patients with hemophilia A and inhibitors by achieving baseline hemostatic control. Based on the HAVEN studies, emicizumab markedly reduces annualized bleeding rates and is FDA-approved for prophylaxis in hemophilia A patients of all ages, regardless of inhibitor status. In the HAVEN2 interim analysis, only 3/57 pediatric patients receiving emicizumab prophylaxis required treatment for an acute bleeding event after a 9-week median observation time. We report 3 patients with severe hemophilia A and a history of inhibitors receiving emicizumab prophylaxis with severe or refractory bleeding episodes to highlight the importance of vigilance and surveillance of children with severe hemophilia A on emicizumab. Methods: This retrospective analysis includes patients between 0-21 years of age with severe hemophilia A (fVIII activity < 1%) receiving emicizumab prophylaxis and admitted for the management of an acute bleeding episode following emicizumab's FDA approval in November 2017. Patients were followed at the Pediatric Hemophilia Treatment Center at the Hemophilia of Georgia Center for Bleeding & Clotting Disorders of Emory and the St. Jude Affiliate Clinic at Novant Health Hemby Children's Hospital. Data collected included demographics, past medical history including inhibitor status, bleeding history, and treatment modalities, and details regarding the presentation, management, and outcome of acute severe bleeding events. Due to the nature of the study, descriptive statistics were primarily used for data analysis. Results: Three patients with severe hemophilia A receiving emicizumab prophylaxis were admitted for the management of 4 severe bleeding episodes. All patients had a history of a fVIII inhibitor. Three of the 4 bleeding episodes were trauma-induced while 1 occurred spontaneously. For the traumatic episodes, all patients presented with worsening symptoms approximately 1 week following the inciting event. All patients had a normal aPTT at the time of presentation, ruling out a significant anti-drug antibody (emicizumab level not available). A patient with a low-titer inhibitor developed an epidural hematoma following a trampoline injury and was treated with continuous infusion of recombinant factor VIII (rfVIII), adjusting the rate to achieve chromogenic fVIII activity of 100% for 14 days. Following 14 days, he was started on rfVIII 50 IU/kg Q12 hours with a goal fVIII activity of 50%. His rfVIII dosing interval was gradually weaned to every other day while in inpatient rehabilitation. As outlined in Table 1, the remaining 3 bleeding events were initially managed with recombinant activated factor VII (rfVIIa) dosed at 80-90 mcg/kg/dose with escalating frequency for an average of 8 days. However, due to lack of improvement, treatment was changed to low-dose activated prothrombin complex concentrates (aPCC; 10-15 IU/kg/dose Q12-24 hours for an average of 7 days). In all 3 of these events, the hematomas improved after treatment with aPCC. No patient experienced thrombotic microangiopathy, thrombosis, or had evidence of DIC while receiving these treatment regimens. Discussion/Conclusion: Pharmacokinetic analysis of emicizumab suggests that following the standard 4-week loading phase, trough plasma emicizumab concentrations obtained prior to a 1.5 mg/kg once weekly maintenance dose correlates with at least 10-15 IU/dL equivalent fVIII activity. This degree of thrombin generation should be sufficient to prevent severe spontaneous bleeding episodes in most patients. However it does not preclude significant trauma-induced bleeding or spontaneous bleeding in inhibitor patients. Based on our cases, providers should maintain a high index of suspicion for acute bleeding in patients receiving emicizumab prophylaxis. Serious bleeding events, although rare, may have a more insidious onset in patients receiving emicizumab. Furthermore, despite the baseline hemostasis achieved with emicizumab, acute bleeding events may still require aggressive therapy. Our cases suggest that low-dose aPCC or continuous infusion fVIII may be feasible options for treating acute bleeding events in patients with hemophilia A and inhibitors receiving emicizumab prophylaxis. Disclosures Zimowski: Pfizer: Research Funding; National Hemophilia Foundation: Other: Medical Loan Reimbursement, Research Funding. Batsuli:Octapharma: Membership on an entity's Board of Directors or advisory committees; Bayer: Membership on an entity's Board of Directors or advisory committees; Genetech: Membership on an entity's Board of Directors or advisory committees. Bryant:Novo Nordisk: Other: PI on Novo Nordisk sponsored Studies. McDaniel:Genentech: Membership on an entity's Board of Directors or advisory committees. Tickle:National Hemophilia Foundation: Research Funding. Meeks:Bayer: Membership on an entity's Board of Directors or advisory committees; Genentech: Membership on an entity's Board of Directors or advisory committees; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees; Bioverativ: Membership on an entity's Board of Directors or advisory committees; Takeda-Shire: Membership on an entity's Board of Directors or advisory committees; HEMA Biologics: Membership on an entity's Board of Directors or advisory committees. Sidonio:Genetech: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda-Shire: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bioverativ: Membership on an entity's Board of Directors or advisory committees, Research Funding; Octapharma: Membership on an entity's Board of Directors or advisory committees, Research Funding; Grifols: Membership on an entity's Board of Directors or advisory committees, Research Funding; Biomarin: Membership on an entity's Board of Directors or advisory committees; Uniqure: Membership on an entity's Board of Directors or advisory committees; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees; Kedrion: Research Funding.

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Plerixafor (Mozobil ®)Plus G-CSF Is Effective in Mobilizing Hematopoietic Stem Cells in Patients with Concurrent Thrombocytopenia Undergoing Autologous Hematopoietic Stem Cell Transplantation.

Blood ◽

10.1182/blood.v114.22.3229.3229 ◽

2009 ◽

Vol 114 (22) ◽

pp. 3229-3229 ◽

Cited By ~ 1

Author(s):

Ivana N Micallef ◽

Eric Jacobsen ◽

Paul Shaughnessy ◽

Sachin Marulkar ◽

Purvi Mody ◽

...

Keyword(s):

Stem Cell ◽

Platelet Count ◽

Board Of Directors ◽

Research Funding ◽

Advisory Committees ◽

Hematopoietic Stem ◽

Platelet Counts ◽

Cd34 Cells ◽

Low Platelet Count ◽

Equity Ownership

Abstract Abstract 3229 Poster Board III-166 Introduction Low platelet count prior to mobilization is a significant predictive factor for mobilization failure in patients with non-Hodgkin's lymphoma (NHL) or Hodgkin's disease (HD) undergoing autologous hematopoietic stem cell (HSC) transplantation (auto-HSCT; Hosing C, et al, Am J Hematol. 2009). The purpose of this study is to assess the efficacy of HSC mobilization with plerixafor plus G-CSF in patients with concomitant thrombocytopenia undergoing auto-HSCT. Methods Patients who had failed successful HSC collection with any mobilization regimen were remobilized with plerixafor plus G-CSF as part of a compassionate use program (CUP). Mobilization failure was defined as the inability to collect 2 ×106 CD34+ cells/kg or inability to achieve a peripheral blood count of ≥10 CD34+ cells/μl without having undergone apheresis. As part of the CUP, G-CSF (10μg/kg) was administered subcutaneously (SC) every morning for 4 days. Plerixafor (0.24 mg/kg SC) was administered in the evening on Day 4, approximately 11 hours prior to the initiation of apheresis the following day. On Day 5, G-CSF was administered and apheresis was initiated. Plerixafor, G-CSF and apheresis were repeated daily until patients collected the minimum of 2 × 106 CD34+ cells/kg for auto-HSCT. Patients in the CUP with available data on pre-mobilization platelet counts were included in this analysis. While patients with a platelet count <85 × 109/L were excluded from the CUP, some patients received waivers and were included in this analysis. Efficacy of remobilization with plerixafor + G-CSF was evaluated in patients with platelet counts ≤ 100 × 109/L or ≤ 150 × 109/L. Results Of the 833 patients in the plerixafor CUP database, pre-mobilization platelet counts were available for 219 patients (NHL=115, MM=66, HD=20 and other=18.). Of these, 92 patients (NHL=49, MM=25, HD=8 and other=10) had pre-mobilization platelet counts ≤ 150 × 109/L; the median platelet count was 115 × 109/L (range, 50-150). The median age was 60 years (range 20-76) and 60.4% of the patients were male. Fifty-nine patients (64.1%) collected ≥2 × 109 CD34+ cells/kg and 13 patients (14.1%) achieved ≥5 × 106 CD34+ cells/kg. The median CD34+ cell yield was 2.56 × 106 CD34+ cells/kg. The proportion of patients proceeding to transplant was 68.5%. The median time to neutrophil and platelet engraftment was 12 days and 22 days, respectively. Similar results were obtained when efficacy of plerixafor + G-CSF was evaluated in 29 patients with platelet counts ≤ 100 × 109/L (NHL=12, MM=10, HD=3 and other=4). The median platelet count in these patients was 83 × 109/L (range, 50-100). The median age was 59 years (range 23-73) and 60.4% of the patients were male. The minimal and optimal cell dose was achieved in 19(65.5%) and 3(10.3%) patients, respectively. The median CD34+ cell yield was 2.92 × 106 CD34+ cells/kg. The proportion of patients proceeding to transplant was 62.1%. The median time to neutrophil and platelet engraftment was 12 days and 23 days, respectively. Conclusions For patients mobilized with G-CSF alone or chemotherapy ±G-CSF, a low platelet count prior to mobilization is a significant predictor of mobilization failure. These data demonstrate that in patients with thrombocytopenia who have failed prior mobilization attempts, remobilization with plerixafor plus G-CSF allows ∼65% of the patients to collect the minimal cell dose to proceed to transplantation. Thus, in patients predicted or proven to be poor mobilizers, addition of plerixafor may increase stem cell yields. Future studies should investigate the efficacy of plerixafor + G-CSF in front line mobilization in patients with low platelet counts prior to mobilization. Disclosures Micallef: Genzyme Corporation: Membership on an entity's Board of Directors or advisory committees, Research Funding. Jacobsen:Genzyme Corporation: Research Funding. Shaughnessy:Genzyme Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Marulkar:Genzyme Corporation: Employment, Equity Ownership. Mody:Genzyme Corporation: Employment, Equity Ownership. van Rhee:Genzyme Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.

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Evaluation of Bleeding-Related Episodes in Patients with Chronic Immune Thrombocytopenia (ITP) Treated with Romiplostim in Two Phase 3 Placebo-Controlled Clinical Trials.

Blood ◽

10.1182/blood.v114.22.891.891 ◽

2009 ◽

Vol 114 (22) ◽

pp. 891-891 ◽

Cited By ~ 1

Author(s):

Ilene Ceil Weitz ◽

Miguel A Sanz ◽

David H. Henry ◽

Martin Schipperus ◽

Bertrand Godeau ◽

...

Keyword(s):

Platelet Count ◽

Board Of Directors ◽

Research Funding ◽

Rescue Medication ◽

Bleeding Event ◽

Bleeding Events ◽

Phase 3 ◽

Advisory Committees ◽

Platelet Counts ◽

Chronic Itp

Abstract Abstract 891 Background: Chronic Immune thrombocytopenia (ITP) is characterized by low platelet counts and increased risk of bleeding. Rescue medications used to treat or prevent bleeding produce transient increases in platelet counts but may be associated with additional toxicities and costs. Romiplostim, approved for the treatment of adult chronic ITP, is a TPO mimetic peptibody protein that increases platelet production. Previously published data from phase 3 romiplostim trials showed that despite the increased use of rescue medication in the placebo arm, patient (pt) incidence of bleeding was reduced in the romiplostim arm vs placebo arm: 15% vs 34% (p = 0.02) for bleeding of grade ≥2 severity and 7% vs 12% (p=0.36) for grade ≥3 severity. Objective: To evaluate the effects of romiplostim treatment on bleeding outcomes in the phase 3 placebo controlled studies in chronic ITP pts with and without previous splenectomy. Bleeding events were captured as adverse events making it difficult to identify a single event reported multiple times versus persistent or recurrent bleeding. Further, we have developed a composite endpoint, termed bleeding-related episodes (BREs), which combines bleeding events and rescue medication administration to account for use of rescue medications to prevent bleeding. Methods: Adults with chronic ITP and a mean baseline platelet count <30 × 109/L were eligible. The previously published studies were conducted separately in splenectomized and nonsplenectomized populations. Pts were randomized (2:1) to receive romiplostim or placebo by subcutaneous injection once weekly for 24 weeks, with dose adjustments to maintain platelet counts between 50-200 × 109/L. Rescue medications were permitted to treat or prevent bleeding and included immunoglobulins, platelet transfusions, corticosteroids, or an increase in dose or frequency of a concurrent ITP medication. A BRE was defined as an actual bleeding event and/or the use of rescue medication. To collapse related events into episodes, events (bleeding events and/or the use of rescue medication) that occurred concurrently or within 3 days of each other were considered a single BRE. Bleeding events beginning 7 or more days after the start of the initial bleeding event were considered a new BRE. To account for differences in time spent on-study, rates of BRE per 100 pt-weeks were calculated. Results: A total of 125 pts (41 placebo, 84 romiplostim) were enrolled in the two studies. Baseline characteristics were well-balanced between the placebo and romiplostim-treated groups. During the treatment period, the rate of BREs was lower in the romiplostim group than in the placebo group, and results were consistent between splenectomized and nonsplenectomized pts (Table). Across both studies, the rate of BREs was reduced by 55% in pts receiving romiplostim compared to those receiving placebo (95% CI, 41% to 65%). BREs were more frequent at platelet counts <50 × 109/L (Table). BREs associated with hospitalizations were less common among romiplostim- than placebo-treated pts, and occurred at platelet counts <50 × 109/L in 10 of 11 cases. Corticosteroids (58 romiplostim, 38 placebo) and immunoglobulins (30 romiplostim, 73 placebo), were the most commonly used rescue medications and the rate of BREs including immunoglobulins was reduced by 88% in pts receiving romiplostim compared to placebo. Conclusions: In adults with chronic ITP, romiplostim was associated with a significant reduction in BREs compared to placebo. There was a marked reduction in BREs requiring immunoglobulins in the romiplostim arm compared to the placebo arm. Results were comparable in splenectomized and nonsplenectomized populations. The platelet count for a BRE starting ≥1 day after a platelet count measurement was calculated from the 2 proximal weekly measurements. Disclosures: Weitz: Amgen Inc.: Speakers Bureau. Sanz:Amgen Inc.: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Henry:Amgen Inc.: Research Funding, Speakers Bureau; Orthobiotech: Research Funding, Speakers Bureau; Watson Pharma: Research Funding, Speakers Bureau. Schipperus:Amgen Inc.: Membership on an entity's Board of Directors or advisory committees. Godeau:Amgen Inc.: Consultancy, Research Funding; Laboratoire Français de Fractionnement et de Biotechnologies (LFB): Consultancy; Roche: Research Funding. Gleeson:Amgen Inc.: Consultancy, Research Funding. Danese:Amgen Inc.: Consultancy, Research Funding. Deuson:Amgen Inc.: Employment, Equity Ownership.

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The Population-Based ‘real world’ of Low Risk Myelodysplastic Syndromes; Second Interim Analysis of the European LeukemiaNet MDS Registry at 800 Registered New Patients

Blood ◽

10.1182/blood.v116.21.1867.1867 ◽

2010 ◽

Vol 116 (21) ◽

pp. 1867-1867

Author(s):

David Bowen ◽

Alex Smith ◽

Jackie Droste ◽

Pierre Fenaux ◽

Argyris Symeonidis ◽

...

Keyword(s):

Bone Marrow ◽

Platelet Count ◽

Creatinine Clearance ◽

Board Of Directors ◽

Neutrophil Count ◽

Real World ◽

Research Funding ◽

Population Based ◽

Low Risk ◽

Advisory Committees

Abstract Abstract 1867 Background: The European LeukemiaNet MDS Registry programme is the largest and most comprehensive prospective population-based registry of ‘low-risk’ MDS patients followed from diagnosis. Objective: The primary objective of this study is to describe the demographics and the disease-management of newly diagnosed MDS patients within IPSS low and intermediate-1 categories. Methods: The project recruits patients from 107 sites in 11 countries, ranging from 2–25 sites per country and including a high proportion of non-University centres in small cities. Consecutive eligible adult patients are registered within 3 months of diagnosis. Local diagnosis is accepted and a large dataset is collected including laboratory data, clinical information (including co-morbidity and concomitant medication) plus health utility (EQ-5D). Data are entered via a web portal and are source verified by study monitoring visits to sites. Results: As of July 2010, 828 patients are registered; data are presented for the first 800 patients. Recruitment is highest from France (n=237) then UK (104), Greece (99), Spain (92), and Sweden (73). Median age is 74.2 yrs (range 18.7–95.3) and from the four largest recruiting countries is 74.6–77.1 yrs. Sixty one percent of patients are male. Twenty patients are non-Caucasian (n=763). Body mass index is overweight (WHO definition) in 43.4% pts and obese in 18.3%, comparable to WHO data for the general adult population (http://apps.who.int/bmi/index.jsp). RCMD is the largest WHO subgroup (34%), followed by RARS (19%), RA (18.4%), RAEB-1 (12.5%), del5q (5.4%), MDS-U (3.5%) and RAEB-2 (0.5%). All WHO subgroups have male predominance except del5q with a striking female excess (79%). IPSS score (n=743) is 0 (52.3%), 0.5 (33.2%), and 1 (14.4%). 84.5% patients have IPSS ‘good’ cytogenetics. 19% patients have 0 cytopenias, 53% 1 cytopenia, 20% 2 cytopenias and 8% 3 cytopenias. WPSS category (with transfusion dependence assessed at time of registration, n=727) is Very Low (35.5%), Low (39.5%), Intermediate (21%), High (4%). Bone marrow features: mean no. of dysplastic lineages = 1.9, bone marrow ring sideroblasts percent = 0 (60% pts), <15 (11.5%), ≥15<50 (19.2%), ≥50 (9.6%). Median haemoglobin (Hb) concentration at presentation is 10.1 g/dl; 36% values were < 10 g/dl and 10% < 8 g/dl. Hb decreased with age (categorical variable Hb. <13>11.5, <11.5>10, <10; Χ2 test, P<.0001). Mean neutrophil count was 2.8 × 109/l with 27% values <1.5 × 109/l, 16% < 1 × 109/l, and 5% < 0.5 × 109/l. Median platelet count was 184 × 109/l; 5% patients had values < 50 × 109/l and 3% < 20 × 109/l. Platelet count and neutrophil count did not change with age. Median serum erythropoietin (EPO) concentration (n=418) was 49 IU/l, 81% values were <200 IU/l and 7% > 500 IU/l. Mean creatinine clearance was 71 mls/min with a marked reduction with age (P<.0001). Baseline serum EPO correlated with Hb. (r=.37, P<.0001), creatinine clearance (r=.22, P<.0001) and age (r=.1, P<.0001). The relationship between creatinine clearance, baseline EPO and response to EPO therapy will be explored. Discussion: This registry records data from the ‘real world’, namely what the hematopathologists in 100 sites diagnose locally as low-risk MDS and will as such be managed as MDS. Median age is consistent with other population-based data (US Medicare, Yorkshire Haematological Malignancy Research Network [www.hmrn.org]). In comparison with registries from specialist MDS centres, median age is higher and a lower proportion have del(5q) WHO subtype. Conclusion: The ELN registry clearly maps the diagnosis and management of low-risk MDS in routine clinical practice in hospitals large and small, specialist and non-specialist and is a unique resource. Acknowledgments: The Steering Committee (SC) acknowledges the commitment and enthusiasm from all 107 sites contributing high quality data to the project. The SC is also grateful for the funding commitment of Novartis Oncology Europe through the University of Nijmegen. Disclosures: Bowen: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AMGEN: Honoraria; Celgene: Honoraria, Research Funding; Chugai: Honoraria, Research Funding. Fenaux:Celgene: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Janssen Cilag: Honoraria, Research Funding; ROCHE: Honoraria, Research Funding; AMGEN: Honoraria, Research Funding; GSK: Honoraria, Research Funding; Merck: Honoraria, Research Funding; Cephalon: Honoraria, Research Funding. Hellstrom-Lindberg:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding.

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Rituximab Plus Three Cycles of Dexamethasone In the Treatment of Immune Thrombocytopenia (ITP): a Pilot Study.

Blood ◽

10.1182/blood.v116.21.3697.3697 ◽

2010 ◽

Vol 116 (21) ◽

pp. 3697-3697

Author(s):

Rebecca Elstrom ◽

Soo Y. Lee ◽

James B. Bussel

Keyword(s):

Platelet Count ◽

Pilot Study ◽

Board Of Directors ◽

Initial Treatment ◽

Research Funding ◽

Advisory Committees ◽

Equity Ownership ◽

Almost All

Abstract Abstract 3697 Introduction: Rituximab has been a useful treatment for patients with ITP; many hundreds of patients have been treated. 30–40% of patients will achieve a complete remission (CR: platelet count >150 × 109/l) with initial treatment and, of this group, the CR will last at least a year in almost all patients. However, emerging data suggests that at least 40% of these patients in CR will relapse between 1 and 3 years from initial treatment suggesting that long-term “cures” only occur in 20% of the initial patients. Therefore it would be desirable if CR's could be achieved in more patients and especially if these would be durable in more than 20%. One approach would be to use rituximab maintenance, however it results in suppression of B-cells for more than 2 years. Dexamethasone has also been used to achieve “cure” in ITP especially in adults at or near diagnosis. Cheng's study suggested that approximately 50% of patients would achieve a long-term response with only one 4-day cycle of high dose (40 mg/day) dexamethasone (N Engl J Med, 2003). A follow up study from GIMEMA suggested that 3–4 cycles of dexamethasone would be better than 1 cycle (Blood, 2007). Finally, Zaja's study suggested that rituximab plus one cycle of dexamethasone was superior to dexamethasone alone with a > 50% CR rate at 6 months (Blood, 2010). Therefore, we elected to perform a pilot study to explore the combination of rituximab with three cycles of dexamethasone at 14 day intervals. Methods: Patients with ITP with platelet counts < 30,000 off therapy and in need of treatment were enrolled. The standard dose (4 infusions of 375mg/m2) rituximab was given on days 1, 8, 15 and 22 and dexamethasone 40 mg (adjusted for size) on days 1–4, 15–18, and 29–32. Results: Fourteen patients between the ages of 4 and 53 years with ITP were treated with rituximab and dexamethasone (R&D) (Table 1). All had received previous steroid therapy as well as other treatments. The median platelet count was 40,000 at initiation of rituximab (range 7,000-230,000); several patients with low counts started with dexamethasone prior to initiating Rituximab to sustain their counts during initial treatment. Patients received rituximab weekly for between 2 and 4 doses and dexamethasone for either 2 or 3 courses at intervals between 1 and 8 weeks (median 2 week intervals). A summary of the results is shown in table 2 demonstrating short-lived platelet increases in response to dexamethasone in almost all patients. With short follow up, there were 7 CR's, 3 PR's and 4 NR's. If this was divided by duration of ITP prior to R&D, there were 4 CR's and 1 NR for ≤ 12 months and 3 CR, 3 PR, and 3 NR for > 12 months. More of the children who were treated had chronic disease than did adults explaining their apparently poorer response. Observed toxicities included hyperglycemia, grade 1 and 2 liver function abnormalities, weight gain, and 1 episode of colitis requiring hospitalization. Three patients opted to skip the third cycle of dexamethasone. Conclusion: A regimen of rituximab + 2–3 courses of dexamethasone is active in patients with pretreated ITP with appreciable but usually manageable toxicity. It appears to yield superior results if administered to patients within one year of diagnosis. This combination merits further exploration in a prospective clinical trial. Disclosures: Bussel: Portola: Consultancy; Amgen: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Research Funding; GlaxoSmithKline: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Research Funding; Ligand: Membership on an entity's Board of Directors or advisory committees, Research Funding; Shionogi: Membership on an entity's Board of Directors or advisory committees, Research Funding; Eisai, Inc.: Membership on an entity's Board of Directors or advisory committees; Cangene: Research Funding; Genzyme: Research Funding.

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Final Results from an International, Multi-Center, Single-Arm Study Evaluating the Safety and Efficacy of Romiplostim in Adults with Primary Immune Thrombocytopenia (ITP),

Blood ◽

10.1182/blood.v118.21.3279.3279 ◽

2011 ◽

Vol 118 (21) ◽

pp. 3279-3279 ◽

Cited By ~ 6

Author(s):

Ann Janssens ◽

Michael D. Tarantino ◽

Robert Bird ◽

Maria Gabriella Mazzucconi ◽

Ralph Vincent V. Boccia ◽

...

Keyword(s):

Bone Marrow ◽

Platelet Count ◽

Board Of Directors ◽

Research Funding ◽

Platelet Response ◽

Employment Equity ◽

Advisory Committees ◽

Platelet Production ◽

Platelet Counts ◽

Equity Ownership

Abstract Abstract 3279 Background: ITP is an autoimmune disorder characterized by increased platelet destruction and suboptimal platelet production. Romiplostim stimulates platelet production via the TPO-receptor, and is recommended for second- and third-line treatment of chronic ITP in adults. We report final data from a large prospective study of romiplostim in adults with ITP of varying duration and severity. Methods: Eligibility criteria were broad: patients ≥18 years of age, who had received prior ITP therapies (final protocol amendment: ≥1, previous amendments: ≥3), with low platelet counts (final amendment: ≤ 30 × 109/L, previous amendments: ≤ 10, ≤ 20 × 109/L) or experiencing uncontrolled bleeding. The only excluded comorbidities were: hematological malignancy, myeloproliferative neoplasms, MDS and bone marrow stem cell disorder. Romiplostim was initiated at 1 (final amendment) or 3 (previous amendments) μg/kg/week, with dose adjustments allowed to maintain platelet counts ≥50 × 109/L. Patients could continue on study until they had access to commercially available romiplostim. Rescue medications were allowed at any time; concurrent ITP therapies could be reduced when platelet counts were > 50 × 109/L. Primary endpoint was incidence of adverse events (AEs) and antibody formation. Secondary endpoint was platelet response, defined as either (1) doubling of baseline count and ≥ 50 × 109/L or (2) ≥20 × 109/L increase from baseline. Results: A total of 407 patients received romiplostim, 60% of whom were female. Median (Q1, Q3) time since ITP diagnosis was 4.25 (1.20, 11.40) years (maximum 57.1 years), with 51% of patients splenectomised and 39% receiving baseline concurrent ITP therapies. Seventy-one percent of patients completed the study, with requirement for alternative therapy and withdrawn consent the most common reasons for discontinuation (5% each). Median (Q1, Q3) on-study treatment duration was 44.29 (20.43, 65.86) weeks (maximum 201 weeks), with a total of 20,201 subject-weeks on study. Incidence and type of AEs were consistent with previous studies. The most common serious treatment-related AEs were cerebrovascular accident, headache, bone marrow reticulin fibrosis (with no evidence of positive trichrome staining for collagen and no evidence suggesting primary idiopathic myelofibrosis), nausea, deep vein thrombosis, hemorrhage and pulmonary embolism, with each reported in 2 of 407 (0.5%) patients. All other serious treatment-related AEs were each reported in one patient. Eighteen patients died; 3 deaths (hemolysis, intestinal ischaema, aplastic anemia) were considered treatment-related. No neutralizing antibodies to romiplostim or TPO were reported. Approximately 90% of patients achieved each of the platelet response definitions, regardless of splenectomy status. Overall, median (Q1, Q3) time to response was 2 (1, 4) weeks for response definition 1, and 1 (1, 3) week for response definition 2. Median (Q1, Q3) baseline platelet count was 14 (8, 21) × 109/L. After 1 week of treatment median (Q1, Q3) platelet count had increased to 42 (18, 101) × 109/L. From week 8 onwards, and excluding counts within 8 weeks of rescue medication use, median platelet counts were consistently above 100 × 109/L (range 101.0–269.5 × 109/L). Median (Q1, Q3) average weekly romiplostim dose was 3.62 (1.99, 6.08) μg/kg. Summary/conclusions: This is the largest prospective study in adult ITP reported to date. The data reported here are similar to those reported for previous romiplostim studies, with romiplostim able to safely induce a rapid platelet response in adult ITP patients with low platelet counts or bleeding symptoms. Romiplostim is an important, well-tolerated, treatment option for adult ITP patients, which significantly increases and maintains platelet counts. Adverse Event Subject Incidence Platelet Response Disclosures: Janssens: Amgen: Consultancy; Roche: Speakers Bureau; GSK: Membership on an entity's Board of Directors or advisory committees. Tarantino:Cangene corporation: Research Funding; Baxter: Research Funding; Talecris: Honoraria, Speakers Bureau; Up-to-date: Patents & Royalties; The Bleeding and Clotting Disorders Institute: Board Member. Bird:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; GSK: Membership on an entity's Board of Directors or advisory committees. Boccia:Amgen: Equity Ownership, Honoraria, Speakers Bureau. Lopez-Fernandez:Amgen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Kozak:Amgen: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Steurer:Amgen: Honoraria. Dillingham:Amgen Limited: Employment, Equity Ownership. Lizambri:Amgen: Employment, Equity Ownership.

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Sports Participation in Children with ITP: A Case for Liberalization?

Blood ◽

10.1182/blood.v120.21.3339.3339 ◽

2012 ◽

Vol 120 (21) ◽

pp. 3339-3339 ◽

Cited By ~ 1

Author(s):

Sophie Brigstocke ◽

Catherine E. McGuinn ◽

James B Bussel

Keyword(s):

Platelet Count ◽

Board Of Directors ◽

Research Funding ◽

Sports Participation ◽

Contact Sport ◽

Advisory Committees ◽

Contact Sports ◽

Platelet Counts ◽

Risk Of Injury ◽

Frequency Of Sports Participation

Abstract Abstract 3339 Background: Children with ITP are at risk for bleeding. ITP is one of many conditions for which the American Academy of Pediatrics advises a pre-sports participation evaluation to assess the risk of injury (Rice 2008). However, restrictions in sports participation might deny the many evidence-based benefits of such physical activity usually accessible for US school-aged youth, thereby presenting significant health and quality of life issues. Aims: To better assess the frequency of sports participation and sports-related injury outcomes relative to contact level by gathering data via questionnaire from a convenience sample of children with persistent and chronic ITP. Methods: Fourteen different types of sports activities were included in this IRB-approved questionnaire and were classified as contact, limited contact, or non-contact as determined by the American Academy of Pediatrics Council on Sports Medicine and Fitness (Rice 2008). Questions were aimed at the frequency of sports participation, types of sports played, sports-related injuries (including bleeding), medical care required for injuries, and comfort regarding continued participation in a sport after sustaining an injury. For each sport not played, questions assessed reasons for the subject's decision to refrain from participation. Patients were categorized according to their platelet levels: counts ≤ 50, 50–150, >150; counts ≤ or >50; counts ≤ or >30 (×109/L). Proportions of data involving 2 groups were compared in a contingency table using Fisher's exact test with trends ≤ 0.01 and significance ≤ 0.025. Results: Twelve subjects (19%) did not participate in any sports. Thirty-six (56%), including patients across all platelet counts, participated in at least one contact sport. There was no statistically significant association (p > 0.1) between the subject's platelet count and the contact level of sport chosen to play. However, a significant association was found between higher frequency of sports participation and higher platelet count (analyzed by groups ≤ or >50 and counts ≤ or >30 (×109/L)) when the highest frequency of participation in any sport (regardless of contact level) was assessed (p < 0.025). When only the sport with the highest contact rating was considered, patients with higher counts played their highest contact sport more frequently than did those patients with lower counts. In particular, subjects with counts ≤ 30 ×109/L played their highest contact sport less frequently, eg more commonly < 1x/month, compared to subjects with platelet counts > 30 ×109/L who played more commonly > 1x/month (p=0.025) [figure]. Twenty injuries were recorded across 10 different sports and 17 patients, but no serious bleeding injuries were reported. There was a statistically significant association (p = 0.002) between higher contact levels and greater incidence of injury. However, there was no statistically significant association (p > 0.1) between estimated platelet count at time of injury and the contact level of sport. As recorded by the patients and/or the patients' parents, 26% of general concerns came from physicians, 53% from parents and 21% from patients themselves. Data collected on the participants' personal concerns showed that higher platelet counts were associated with fewer personal concerns being expressed (p < 0.025). However, when each personal concern was analyzed there were no statistically significant trends or associations (p > 0.1) found between any specific concern and platelet count. Across all contact and limited-contact sports, the most frequently expressed concern was that the sport was too dangerous. The most frequently expressed concern for non-contact sports was that the patient was too tired to play. Conclusions: There was a significant association between higher frequency of sports participation, but not higher contact level, with higher platelet counts. Higher incidences of injury were associated with higher contact levels, but not with lower platelet counts, suggesting that children with ITP can participate in non-contact sports and many contact and limited-contact sports with low risk of injury. Therefore, we believe that sports participation for children with ITP is generally too restricted and greater encouragement for children to be athletic in the sport of their choice is warranted. Disclosures: Bussel: Sysmex: Research Funding; Shionogi: Membership on an entity's Board of Directors or advisory committees, Research Funding; Eisai: Membership on an entity's Board of Directors or advisory committees, Research Funding; Ligand: Membership on an entity's Board of Directors or advisory committees, Research Funding; Immunomedics: Research Funding; IgG of America: Research Funding; Genzyme: Research Funding; GlaxoSmithKline: Family owns GSK stock, Family owns GSK stock Other, Membership on an entity's Board of Directors or advisory committees, Research Funding; Cangene: Research Funding; Amgen: Family owns Amgen stock Other, Membership on an entity's Board of Directors or advisory committees, Research Funding; Portola: Consultancy.

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The Influence Of KIR Haplotype In ITP Incidence, Treatment Response and Bleeding Symptoms

Blood ◽

10.1182/blood.v122.21.2316.2316 ◽

2013 ◽

Vol 122 (21) ◽

pp. 2316-2316

Author(s):

Bethan Psaila ◽

Nayla Boulad ◽

Emily Leven ◽

Naznin Haq ◽

Christina Soo Lee ◽

...

Keyword(s):

Platelet Count ◽

B Cells ◽

Nk Cells ◽

Board Of Directors ◽

Research Funding ◽

Nk Cell ◽

Advisory Committees ◽

Kir Genes ◽

Number Of Patients

Abstract The pathogenesis of immune thrombocytopenia (ITP) is multifactorial, with both cellular and humoural immune dysfunction. The role of NK cells has not been well defined in ITP but in other diseases NK cells have a role in rejecting “foreign” eg transplanted organ or tumor, and also acting against self as occurs in autoimmunity. NK cell activity is orchestrated by the balance of activating vs. inhibitory signalling, in particular via the killer cell immunoglobulin-like receptor (KIR) family of receptors. Significant variation exists in KIR allelic subtype and copy number for the KIR between individuals, and associations have been made with certain haplotypes and a number of autoimmune disorders including rheumatoid arthritis, scleroderma and diabetes. Previous reports have demonstrated a reduction in natural killer (NK) cell number and function in ITP and expression of inhibitory KIR genes is increased in patients in remission vs. active ITP. Methods To explore whether a particular KIR haplotype might predispose to ITP, and also affect response to ITP treatment, we performed KIR genotyping using the Invitrogen SSP kit on 92 patients attending a haematology centre in New York and compared the results to data from 213 controls taken from the USA Eastern Database. Genomic DNA was typed for the inhibitory KIR genes KIR2DL1, KIR2DL2, KIR2DL5A (alleles 001 and 002), KIR2DL5B (alleles 002-004, 06, and 007), KIR3DL1, KIR3DL3; the activating KIR genes KIR2DS1, KIR2DS2, KIR2DS3, KIR2DS4, KIR2DS5, KIR3DS1; the framework genes KIR2DL3, KIR2DL4, KIR3DL2, KIR3DP1; and the pseudogene KIR2DP1. The patients with ITP had been or were receiving treatment with IVIG (n=64), corticosteroids (72) and rituximab (37). Bleeding symptoms were recorded. Response to treatment was defined as complete - platelet count increase to > 100 x 109/mL; partial - platelet count increase to > 50 x 109/mL; or no response. For the purpose of analysis, PRs and CRs were combined. A comprehensive database allowed a logistic regression, assessing both responses to treatments, platelet counts, neutrophil counts, CRP, lymphocyte subsets and bleeding symptoms. Results The expression of two inhibitory KIR genes, 2DL1 and 3DL1, was significantly lower in the patients with ITP as compared to controls (87% 2DL1 and 87% 3DL1 compared to 99% in controls - P < 0.02). Response to rituximab was strongly related to KIR haplotype expression. 2DL1 expression was higher among nonresponders to Rituximab (100% of non responders compared to 82% of responders), whereas 2DL3 expression was significantly lower (79% compared to 90%) (P < 0.05, Figure 1B). Separately, patients with the 2DS3 allele, an activatory KIR, were 5.5 times more likely to have experienced significant bleeding. Conclusions Although these findings are preliminary and require further investigation, these data suggest that increased cytotoxic autoimmunity due to reduced KIR inhibition may be associated with the development of ITP and possibly contribute importantly to the pathogenesis. Anti-CD20 targeting therapy directed at B cells was strongly influenced by 2 different KIRs (1 upregulated and one down-regulated) emphasizing the potential role of NK cells in elimination of tissue-based (nodal) B cells. Finally a more pronounced clinical phenotype with a markedly higher incidence of severe bleeding associated with an increased activatory KIR expression demonstrates the role of NK cells in bleeding presumably via their effects on either endothelial cells or platelet function. These exciting findings will be pursued for confirmation in a larger number of patients. Disclosures: Bussel: Amgen: Family owns stock Other, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Cangene: Research Funding; Genzyme: Research Funding; GlaxoSmithKline: Family owns stock, Family owns stock Other, Membership on an entity’s Board of Directors or advisory committees, Research Funding; IgG of America: Research Funding; Immunomedics: Research Funding; Ligand: Membership on an entity’s Board of Directors or advisory committees, Research Funding; Eisai: Membership on an entity’s Board of Directors or advisory committees, Research Funding; Shionogi: Membership on an entity’s Board of Directors or advisory committees, Research Funding; Sysmex: Research Funding; Symphogen: Membership on an entity’s Board of Directors or advisory committees.

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