ALBERT

Description: Abstract 1515 Poster Board I-538 BACKGROUND Acute chest syndrome (ACS) is a common cause of morbidity and mortality for individuals with sickle cell disease (SCD). The treatment of ACS is mainly supportive. Prior studies have shown that intravenous pulse-dose corticosteroids, such as dexamethasone, can decrease the duration and morbidity of ACS. However, such treatment may also precipitate ‘rebound‘ episodes of vaso-occlusive pain in some individuals that might negate the overall benefit of corticosteroids. Tapered corticosteroid therapy might decrease the rebound effect while maintaining therapeutic benefit. Therefore, we designed a prospective study to begin to test this hypothesis and to assess biomarkers that might clarify the therapeutic and toxic mechanisms of corticosteroids in SCD, predict outcome, and guide therapy. METHODS We conducted a multi-center, placebo-controlled pilot study to test the feasibility and safety of high-dose oral dexamethasone followed by a taper for ACS. Children and adults with SCD and ACS of any severity were randomized to dexamethasone (0.3 mg/kg q12h x 2, 0.3 mg/kg q24h x 2, 0.2 mg/kg q24h x 2, 0.1 mg/kg q24h x2, then stop) or placebo to start within 24 hours of diagnosis. All subjects received standard, protocol-directed supportive care for ACS. We defined the duration of ACS using a novel, objective tool that assessed rate and effort of breathing, oxygen saturation in room air, thoracic pain, and use of supplemental oxygen and ventilatory support. The primary outcomes were the duration of ACS and the duration of hospitalization for ACS. We also measured a panel of biomarkers before, during and after therapy. Inflammatory biomarkers included high sensitivity C-reactive protein and secretory phospholipase A2 (sPLA2). White cell and endothelial activation markers included sVCAM-1, sICAM-1, vWF:Ag and vWF:RCoF, sE-selectin, sP-selectin, sL-selectin, nitric oxide metabolites (NO), and whole blood tissue factor. We used generalized linear mixed models controlling for age to test for differences between treatment groups. RESULTS We enrolled 12 subjects (9 children, 3 adults; mean age 17.3 years, range 5 - 45) with homozygous sickle cell anemia at 4 centers and randomized 11 (1 drop-out) to either dexamethasone (N=5) or placebo (N=6). The objective ACS assessment tool was completed on all subjects without difficulty. In this pilot study, dexamethasone reduced the duration of hospitalization (41.5 vs 62.3 hrs; P=0.024), but not the duration of ACS (log of duration 2.4 vs 3.5 hrs; P=0.127), supplemental oxygen (17.5 vs 41.2 hrs; P=0.876), hypoxemia (13.8 vs 34.3 hrs; P=0.770), or total opioid usage in morphine equivalents (54.4 vs 68.8 mg; P=0.885). There were no statistically significant differences in adverse events between arms. However, 3 patients treated with dexamethasone had a painful event in the 2 weeks after hospital discharge (1 required re-hospitalization), compared to 1 patient in the placebo group (0 re-hospitalizations). No marked leukocytosis occurred in either treatment group, but the leukocyte count at 1-week follow-up had decreased less from baseline in the dexamethasone group compared to placebo (-17.7 vs -37.6%; P=0.028). The baseline sPLA2 concentration was 3 100 ng/mL in 4/5 and 4/6 patients in the dexamethasone and placebo arms. The white cell activation marker, sL-selectin was significantly decreased at 1-week follow-up in the dexamethasone group compared to placebo (573.8 ng/mL vs 742.8; change from baseline -121.2 vs 57.2; P

Description: Controversy exists regarding management of children newly diagnosed with immune thrombocytopenic purpura (ITP). Drug treatment is usually administered to prevent severe hemorrhage, although the definition and frequency of severe bleeding are poorly characterized. Accordingly, the Intercontinental Childhood ITP Study Group (ICIS) conducted a prospective registry defining severe hemorrhage at diagnosis and during the following 28 days in children with ITP. Of 1106 ITP patients enrolled, 863 were eligible and evaluable for bleeding severity assessment at diagnosis and during the subsequent 4 weeks. Twenty-five children (2.9%) had severe bleeding at diagnosis. Among 505 patients with a platelet count less than or equal to 20 000/mm3 and no or mild bleeding at diagnosis, 3 (0.6%), had new severe hemorrhagic events during the ensuing 28 days. Subsequent development of severe hemorrhage was unrelated to initial management (P = .82). These results show that severe bleeding is uncommon at diagnosis in children with ITP and rare during the next 4 weeks irrespective of treatment given. We conclude that it would be difficult to design an adequately powered therapeutic trial aimed at demonstrating prevention of severe bleeding during the first 4 weeks after diagnosis. This finding suggests that future studies of ITP management should emphasize other outcomes.

Description: We hypothesized that the silent cerebral infarcts (SCI), which affect up to 40% of children with sickle cell disease (SCD), could occur in the setting of acute anemic events. In a prospective observational study of children with and without SCD hospitalized for an illness associated with acute anemia, we identified acute silent cerebral ischemic events (ASCIE) in 4 (18.2%) of 22 with SCD and in 2 (6.7%) of 30 without SCD, using diffusion-weighted magnetic resonance imaging. Children with ASCIE had lower hemoglobin concentration than those without (median 3.1 vs 4.4 g/dL, P = .003). The unique temporal features of stroke on diffusion-weighted magnetic resonance imaging permit estimation of incidence rates for ASCIE of 421 (95% confidence interval, 155-920) per 100 patient-years during acute anemic events for all patients. For children with SCD, the estimated incidence was 663 (95% confidence interval, 182-1707) which is much higher than previously reported. Acute anemic events are common in children with SCD and prevalence could partially account for the high SCI. Some ASCIE (1 of 4 in our study) may be reversible. Alterations in management may be warranted for children with severe anemia to identify unrecognized ischemic brain injury that may have permanent neurocognitive sequelae.

Description: Abstract 1066 Fetal hemoglobin (Hb F) induction (anti-switching therapy) is an effective therapeutic strategy in sickle cell disease (SCD), both for reducing acute complications such as painful episodes and acute chest syndrome, and decreasing hospitalizations and transfusion requirements. Long term use of the only approved anti-switching agent, hydroxyurea (HU) has also been shown to improve survival. Despite this, HU is still not widely prescribed, ∼30% of patients are non-responders, and there are concerns regarding long term use of this cytotoxic agent. There is, therefore, a clear need for alternative anti-switching agents with different mechanism(s) of action, that are not cytotoxic, and that could be used either alone, or in combination with HU to enhance Hb F response. HQK-1001, an orally bioavailable short-chain fatty acid, was shown to promote Hb F synthesis and prolong erythroid survival and proliferation in transgenic mice and non-human primate models. In a Phase 1/2, dose-escalation, placebo-controlled study in 24 patients with SCD, HQK-1001 given at 10, 20, and 30 mg/kg/day for 12 weeks was well tolerated, showed dose-proportional pharmacokinetics (PK), and resulted in dose-dependent increase in Hb F (A Kutlar et al, Blood 2010; 116: Abstract 943). This randomized open-label Phase 2 study is being conducted to evaluate the safety, PK, and effect on Hb F of HQK-1001 administered at a higher dose and for a longer duration than previously studied. Patients with SCD age 12 years and greater were randomized to receive HQK-1001 at 30 or 40 mg/kg daily for 26 weeks. Enrollment at the 50 mg/kg dose level was opened after the Safety Monitoring Committee conducted a planned interim safety data review of the first 12 patients treated for 4 weeks. HQK-1001 is administered as 900 mg tablets, and daily oral iron supplementation is given to patients with plasma ferritin levels less than 700 ng/mL. A minimum of 14 patients stratified 1-to-1 by HU use at baseline will be enrolled at each dose level. Between 25 April 2011 and 5 August 2011, 39 patients have been enrolled and received HQK-1001 at 30 mg/kg (n = 14), 40 mg/kg (n = 14), and 50 mg/kg (n = 11). Patients were enrolled in North America (n = 18), Lebanon (n = 15) and Egypt (n = 6). Median age was 22 years (range, 12–47) and 7 (18%) were less than 18 years old. There were 20 (51%) males and 19 (49%) females. Patients had either Hb-SS (n = 34) or Hb-Sβ0 (n = 5), and 25 (64%) were on HU at baseline and continued HU while on study. Four patients have discontinued HQK-1001 per protocol following a transfusion to treat a SCD complication. One patient discontinued HQK-1001 due to pancreatitis. This patient was found to have a stone in the common bile duct and subsequently died postoperatively from multiorgan failure. The most common adverse events considered by the investigator as possibly drug-related were nausea in 10 patients (26%), abdominal/epigastric pain, vomiting, and headache in 5 (13%) each, and somnolence and dizziness in 3 (8%) each. Drug-related adverse events were graded as mild or moderate except for 1 case each of pancreatitis and gastritis graded as severe. No myelosuppression was observed. Assessment of HQK-1001 effect on Hb F and hemoglobin (Hb) is limited due to short follow-up. In 19 patients in which baseline and Week 4 data are available, the mean value at baseline for Hb was 8.9 g/dL (range, 7.4–11.4) and for Hb F was 1.11 g/dL (range, 0.15–3.33). Eight patients had data available both for Weeks 4 and 8. On Week 8, total Hb increased from baseline by a mean of 0.3 g/dL (range, −0.7 to 1.2) and Hb F increased by a mean of 0.14 g/dL (range, −0.19 to 0.42). The figure reports individual changes in Hb F from baseline to Weeks 4 (dark bars) and Week 8 (light bars), with “X” denoting the 4 patients on HU, and shows an increase in Hb F in 7 of 8 patients for that period. Enrollment is expected to be completed in August 2011 and updated results will be available at the meeting. In conclusion, the safety profile of HQK-1001 is consistent with results reported in prior studies and shows no overlapping toxicity with HU. Hb F is apparently increased in 7 of 8 patients with data available at Week 8, and this increase is seen both in patients receiving HU or not. Longer follow-up is needed to fully assess the safety of HQK-1001 and the extent of its effect on Hb F, total Hb, and SCD-related events. Disclosures: Aiello: HemaQuest Pharmaceuticals: Employment. Johnson:HemaQuest Pharmaceuticals: Employment. White:HemaQuest Pharmaceuticals: Consultancy. Ghalie:HemaQuest Pharmaceuticals: Employment.

Description: The relapse rate in childhood acute lymphoblastic leukemia (ALL) is approximately 30% but few reinduction regimens have investigated the intensive use of polyethylene glycol Escherichia coliasparaginase (PEG-Asp). Therefore, we assessed the pharmocokinetics and efficacy of PEG-Asp in this setting. Children with B-precursor ALL, in first marrow and/or extramedullary relapse were eligible. Reinduction included doxorubicin on day 1, prednisone for 28 days, vincristine weekly for 4 weeks, and PEG-Asp either weekly or biweekly by randomization. Asparaginase levels and antibody to both E coli asparaginase and PEG-asp were measured weekly just before each PEG-asp dose. Overall, 129 of 144 patients (pts) (90%) achieved a complete remission (CR). There was a highly significant difference in CR rates between weekly (69 of 71; 97%) and biweekly (60 of 73; 82%) PEG-Asp dosing (P = .003). Grade 3 or 4 infectious toxicity was common (50%), but only 4 pts died of sepsis during induction. Other toxicities were infrequent and hypersensitivity was rare (6 of 144; 4%). Low asparaginase levels were associated with high antibody titers to either native (P = .024) or PEG asp (P = .0013). The CR rate was significantly associated with higher levels of asparaginase (P = .012). Patients with ALL in first relapse receiving weekly PEG-Asp had a higher rate of second remission compared with biweekly dosing. Low levels of asparaginase were associated with high antibody titers. Increased asparaginase levels may correlate with an improved CR rate. The use of intensive PEG-Asp should be explored further in the treatment of ALL.

Description: The optimal management of prolonged priapism for patients with sickle cell anemia (SCA) has not been established. We prospectively studied in an outpatient setting the efficacy and safety of a procedure that employs aspiration of blood from the corpora cavernosa and irrigation with a dilute epinephrine solution under local anesthesia to relieve priapism in young patients with SCA. If hydration and analgesics failed to produce detumescence or if priapism had lasted 〉4 hours, the protocol was activated in the emergency room or clinic. Fifteen patients with homozygous SCA (Hb SS) were treated on 39 occasions; 10 patients were treated once, 1 patient twice, 2 patients 3 times, 1 patient 6 times, and 1 patient 15 times. Median age of patients at first treatment was 14.3 years (range, 3.9-18.3 years). The procedure was successful in producing immediate detumescence on 37 of 39 occasions (95% efficacy, 95% confidence intervals (CI): 81%-99%). No serious immediate or long-term side effects were observed. None of the patients who demonstrated detumescence required hospitalization. The 2 patients whose priapism persisted after aspiration and irrigation presented with episodes lasting 〉24 hours. All evaluable patients whose priapism resolved after aspiration and irrigation self-reported normal erectile function at a median of 40 months (range, 3-58 months) after the last procedure. Thus, aspiration of the corpora cavernosa followed by irrigation with dilute epinephrine is effective in producing immediate and sustained detumescence and should be the initial therapy employed for patients with SCA and prolonged priapism. (Blood, 2000; 95:78-82)

Description: Introduction: Childhood immune thrombocytopenic purpura (ITP) is a bleeding disorder caused by destruction of platelets with a very small risk of a life threatening bleeding. ICIS Registry I was initiated in 1997 to obtain worldwide prospective data on the natural history of ITP in children. The first analyses of ICIS data showed that 25–47% of the children developed chronic ITP (defined as a platelet count 〈 150 × 109/l 6 months after diagnosis) depending on age. Previous studies in small numbers of patients suggested that intravenous immunoglobulin (IVIG) treatment at diagnosis might reduce the risk of chronic ITP. Therefore, the ICIS Registry I (with data on 〉2000 patients) was used to examine prognostic factors related to chronic ITP. Results: Of the 2605 children with newly diagnosed ITP, between 3 months and 16 years of age, in 1984 the platelet count 6 months after diagnosis was known; 630 (32%) had a platelet count

Description: The Cooperative Study of Sickle Cell Disease reported that dactylitis, severe anemia, and leukocytosis in very young children with sickle cell disease (SCD) increased the risk of later adverse outcomes, including death, stroke, frequent pain, and recurrent acute chest syndrome. This model has not been validated in other cohorts. We evaluated its performance in the Dallas Newborn Cohort, a newborn inception cohort of children with SCD. We studied 168 children (55% male, 97% sickle cell anemia) with a mean follow-up of 7.1 years who provided 1188 patient-years of observation. Of the 23 (13.7%) subjects who experienced adverse events, 2 (1.2%) died, 14 (8.3%) had a stroke, 4 (2.4%) had frequent pain, and 3 (1.8%) had recurrent acute chest syndrome. No relationship existed between early clinical predictors and later adverse outcomes, with the possible exception of leukocyte count. Most subjects who experienced adverse events were predicted to be at low risk for those events. No subject who was predicted to be at high risk actually experienced an adverse outcome. The sensitivity of the model did not rise above 20% until specificity fell below 60%. We suggest that this model not be used as a criterion to initiate early interventions for SCD.

Description: Romiplostim, a thrombopoietin-mimetic peptibody, increases and maintains platelet counts in adults with immune thrombocytopenia (ITP). In this first study of a thrombopoietic agent in children, patients with ITP of ≥ 6 months' duration were stratified by age 1:2:2 (12 months-〈 3 years; 3-〈 12 years; 12-〈 18 years). Children received subcutaneous injections of romiplostim (n = 17) or placebo (n = 5) weekly for 12 weeks, with dose adjustments to maintain platelet counts between 50 × 109/L and 250 × 109/L. A platelet count ≥ 50 × 109/L for 2 consecutive weeks was achieved by 15/17 (88%) patients in the romiplostim group and no patients in the placebo group (P = .0008). Platelet counts ≥ 50 × 109/L were maintained for a median of 7 (range, 0-11) weeks in romiplostim patients and 0 (0-0) weeks in placebo patients (P = .0019). The median weekly dose of romiplostim at 12 weeks was 5 μg/kg. Fourteen responders received romiplostim for 4 additional weeks for assessment of pharmacokinetics. No patients discontinued the study. There were no treatment-related, serious adverse events. The most commonly reported adverse events in children, as in adults, were headache and epistaxis. In this short-term study, romiplostim increased platelet counts in 88% of children with ITP and was well-tolerated and apparently safe. The trial was registered with http://www.clinicaltrials.gov as NCT00515203.