ALBERT

Description: Abstract 1269 Introduction. Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired hematopoietic disorder characterized by the clonal expansion of a PIG-A mutated stem cell and consequent defective synthesis of glycosil phosphatidyl-inositol-anchored proteins, complement-mediated hemolysis, increased incidence of thrombosis, bone marrow failure. PNH and acquired aplastic anemia (AA) are closely related and a reciprocal progression is possible. A relative resistance of the PNH stem cell to the immune-mediated damage can explain the PNH clonal expansion in AA. High resolution flow cytometry analysis (FCA) has revealed a high incidence of minor PNH clones in adult AA patients at diagnosis, predictive for some Authors of a favourable response to the immunosuppressive therapy (IST) (Maciejevki et al, 2001; Ishiyama et al, 2003; Sugimori et al, 2006). “Pure” PNH is a very rare disease in children. Only a few studies have so far evaluated longitudinally PNH clones in pediatric AA patients. Materials and Methods. Ninety AA patients diagnosed in 8 AIEOP (Italian Association of Pediatric Hematology-Oncology) Centers (age at diagnosis 1–20 years, median =10.8, 51 severe AA, 30 very severe AA, 9 non severe AA) were studied: forty-one since diagnosis, 25 during IST, 20 off therapy and 4 selected cases after hematopoietic stem cell transplantation (HSCT). Among the patients followed since diagnosis, 8 received an HLA matched sibling donor HSCT as first line therapy, whereas the other 33 patients were treated with IST according to EBMT protocols (anti-lymphocyte globulin/anti-thymocyte, ciclosporin ± granulocyte colony stimulating factor). The study started in 1998. Peripheral blood PNH cells were detected by lack of CD59 expression on granulocytes by a two-color FCA for CD59 (clone p282-FITC Becton-Dickinson) and CD11b (clone D12-PE Becton-Dickinson); at least 105 cells were analyzed, for a total of 1104 tests. The presence of a population CD11b+/CD59- 〉 0.15% was defined as abnormal; the cut off value was established in 1998 by evaluating 87 normal controls (PNH clones: median = 0.001%, mean+2SD=0.10%). Since 2009 FCA results were confirmed by more sensitive techniques with three or six-color sequential gating analysis for CD45/33/66b or CD45/33/15/24/14/FLAER. Results. A PNH+ clone was observed in 15 patients (36.6%) at diagnosis (clone size 0.17–10.4%), in 10 patients (40%) during IST (clone size 0.16–12.6%) and in 8 patients (40%) off-therapy (clone size 0.16–4.0%). The presence of a PNH+ clone at diagnosis did not predict a favourable response to IST, both in ALG and ATG-treated patients. In 33 patients (16 at diagnosis, 9 in IST, 8 off therapy), the presence of the PNH clone was sporadic or intermittent, whereas in 13 patients (9 at diagnosis, 3 in IST, 1 off therapy) the clone persisted for more than 3 following controls (follow up 6–60 months). Among the 26 PNH- patients at diagnosis, in 10 a PNH clone (clone size 0.16–1.7%) appeared later during IST. Among the 25 patients studied during IST, in one patient PNH clone appearance was associated with the tapering of cyclosporine (figure 1), in two with the relapse when off therapy. In one out of 4 patients treated with HSCT, a PNH clone appeared at time of relapse and disappeared after starting IST with cyclosporine (figure 2). A mild hemolysis was observed in the only 2 patients with a major PNH clone (clone size 12.6 and 10.4% respectively). No thrombotic events were reported. Conclusions. We have observed a significant incidence of minor PNH clones in pediatric AA at diagnosis, as reported in adults. Whereas previous studies in adults correlated the presence of pre-treatment minor PNH clones with a favourable response to IST, we do not confirm those observations both in the present multi-centre as in our previous single-centre study (Timeus et al, 2010), in agreement with Yoshida et al (2008) and Scheinberg et al (2010). The appearance of a PNH clone in a PNH- patient at diagnosis is described as uncommon (Sugimori et al, 2009), however in our series this was observed in 38% of previously PNH- patients. In AA the presence of PNH clones seems related to complex interactions between stem cells, immune-mediated damage and immunosuppressive therapy. A periodic screening for PNH clones in patients with AA is recommended, permitting modulation in IST, early identification of major PNH clones and prompt diagnosis of a frank PNH. Disclosures: Timeus: Alexion Pharma Italy s.r.l.: Research Funding. Dufour:Pfizer: Consultancy.

Description: Background: Immune Thrombocytopenia (ITP) is one of the most common conditions encoutered by the pediatric hematologist. Current first-line therapy includes: observation without drug therapy, corticosteroids and intravenous immune globulin. A minority of patients are refractory to first-line approaches. Second-line treatment options are: immunosuppressive agents and thrombopoietin receptor agonists (TPO-RA). Eltrombopag and Romiplostin are TPO-RA licensed for clinical use. Eltrombopag is, actually, the only TPO-RA approved in Italy (since two years ago) for children, over one year old, with a chronic and/or refractory ITP. Real life data of Eltrombopag are limited. Methods: We performed an Italian multicenter retrospective survey to study the clinical on-label use of TPO-RA, focus on Eltrombopag, in pediatric ITP. Our aims were, primarily, to bring out the prevalence of the use in clinical practice and secondarily to collect data on efficacy and toxicity. Results: We enrolled 69 pediatric ITP subjects from 15 Italian treatment centers (TC). 4 patients received Romiplostin as TPO-RA and were excluded by the analysis. 36/65 patients weer female (55%). Median age at ITP diagnosis: 6 years + 6 months (min 1 y + 2 m; max 16 y + 7 m). Median age at first Eltrombopag assumption: 11 years + 5 months (min 2 y + 0 m; max 17 y + 8 m). Accounting in 344 the total number of chronic ITP subjects treated by TC in the same observation period (July 2016-June 2018), we observed an Eltrombopag clinical use prevalence of 0.19 (95% CI 0.15 to 0.26). We underlined a "no response" to Eltrombopag (platelet count persistently less than 30000 per microliter) in 16/65 (25%); a "partial response" (platelet count between 30000 and 100000 per microliter) in 14/65 (21%) and a "complete response" (platelet count persistently up than 100000 per microliter) in 35/65 (54%). The overall response (partial or complete) was described in 49/65 (75%) children. During the follow up was seen in 16/49 (33%) subjects with initial response a platelet rise that waned to no response. There was no evidence of significant adverse events (clinicians are obliged, to monthly surveillance, by Italian drug agency for hypertransaminasemia and peripheral smear cell abnormalities). Conclusions: Our results demonstrate that Eltrombopag is a therapeutic option quite considered by Italian clinicians. Moreover, according with the percentages of clinical trials, Eltrombopag is safe and effective to rise platelet count. Further studies need to emphasize how factors favor a complete response and to know the incidence of long-term adverse effects. A prospective study designed and driven by Italian Association of Pediatric Hematology Oncology (AIEOP) Coagulation Disorders Working Group is, already, in progress. Disclosures No relevant conflicts of interest to declare.

Description: Autoimmune hemolytic anemia (AIHA) is an uncommon disease of childhood caused by the premature destruction of erythrocytes by autoantibodies. In this rare disease both diagnostic criteria and therapeutic approaches are not well standardized. The Red Cell Working Group of the Pediatric Italian Hematogy and Oncology Association (AIEOP) developed specific recommendations to help Physicians for AIHA management. The document is available on the AIEOP website since November 1st 2013. The Italian Pediatric AIHA Group began an observational, retrospective and prospective study in order to monitor the management of children with AIHA diagnosed from 2010 to 2018, and to assess whether the availability of AIEOP recommendations had an impact on the clinical management of such patients in AIEOP Centers. We collected a national cohort of 159 children with AIHA from 21 AIEOP Centers; 48 patients were diagnosed before November 2013 and 111 patients after that date. Gender was 56% males and 44% females; median age at diagnosis was 47 months, with 11.9% under 12 months of age; 8.2% of children were born prematurely and 3.9% showed congenital malformations. 23.2 % of patients had a familiar history of immunological, hematological or oncological diseases. The median hemoglobin level at diagnosis was 6.1 gr/dL. Table 1 reports the distribution of our cases, according to the different type of autoantibodies. The comparison between the retrospective and prospective study did not reveal significative differences in clinical and biological presentation. The cold IgM forms were mainly post infective (38.4%) or primary forms (53.8%), only one patient had a secondary form due to a primitive immunodeficiency. These patients did not develop other diseases during follow up (median follow up: 28,6 months). The preliminary results of treatment and follow up of the 146 patients with warm antibody AIHA revealed the following: The treatment with conventional dose of steroids (median dose 2 mg/Kg, range 0.7- 3.5 mg/Kg) was started in 94.4% of patients, in 53% of cases on the same day of diagnosis. A high number of children used additional treatment: red blood cell transfusions (51.4%), high dose Prednisolone (59.7%), high dose i.v. Immunoglobulin (49.7%) and Plasma Exchange (1.4%). 9.5% of patients, with poor responsive disease, needed alternative drugs during the first four weeks of therapy. Response criteria were so defined: a complete response was defined as the achievement of an Hb concentration greater than or equal to the lower normal limit for age with no signs of haemolysis, i.e. normal reticulocyte count and bilirubine concentration. A partial response was defined as an increase of Hb 〉2 g/dL without the Hb concentration reaching a normal value for the patient age and no response as an increase of Hb〈 2 g/dL and/or dependence on transfusion. A complete response was reached by 62.5%, 79.3%, 85.1% at 3, 4, 6 weeks respectively. 14.9% of patients had either a partial response or a resistant disease at 6 weeks. IgG/IgG+C3d positivity was a negative prognostic factor, as compared to positivity to C3d only, with the need of a second line treatment (prevalently Mabthera or Mycophenolate Mofetil) in 31.7% vs 0, respectively (p 0.009). Currently 6.1% of the patients were lost to follow up, 1.3% died, 55,8% are in Complete Response without events and 21.9% of the patients are still on treatment . At the last follow up, in the whole "cohort" of warm AIHA, 58% have a Primary form, 15.7% an isolated post infective form and 27.7% a Secondary form (56% Evans Syndrome). The management of the patients diagnosed after November 2013 was mostly in agreement with our recommendations, whose comprehensive therapeutic algorithm is reported in table 2, with prolonged steroid tapering in order to extend the treatment for at least 6 months. The most important difference between the retrospective and prospective study was the duration of first line treatment: 6 months or more, for steroid dependence, in 71.6% of patients in the prospective study versus 52.3% of the retrospective (p 0.031) and, more importantly, the percentage of relapsed patients: 8.3% in the prospective study versus 29.8% of the retrospective (p 0.001), these data need a longer follow up (median follow up: 24 months in the prospective study versus 63 in the retrospective) Disclosures Colombatti: Global Blood Therapeutics: Consultancy; Novartis: Consultancy; AddMedica: Consultancy.

Description: Background and objective. In a previous study we showed encouraging outcome in severe aplastic anemia (SAA) patients treated with anti-lymphocyte globulin (ALG), cyclosporin (CyA) and G-CSF 5mg/Kg/day (Blood2000; 95: 1931–4.). However failure to respond, delayed responses, partial responses, relapses and early deaths remain signifcant problems. The aim of the present study was to test whether an increased dose of G-CSF (10 mg/Kg/day) would reduce these complications. Design and methods. This is a multicenter prospective trial in 77 SAA patients treated with horse ALG (15 mg/kg/day day1–5) and CyA (5 mg/kg/day day 1–180). Patients were randomized to receive G-CSF 5 mg/Kg/day (n=38, group A) or 10 mg/Kg/day (n=39, group B) from day +1 to day +30. All patients then received G-CSF 5 mg/Kg/day from day +31 to day +90. Primary end point was response at day +120. Secondary end points were early deaths , blood counts at day +120, and survival. Results. At day +120 responses were classified as absent, partial, complete in 12, 22, 4 patients in group A and in 23, 7, 9 patients in group B (p=0.001). At last follow up these figures were respectively 9,12,17 vs 19,2,18 (p=0.004). Thirteen patients (5 in group A and 8 in group B) died before day 120 (p=0.3). Median peripheral blood counts an day 120 were comparable in the two groups: Hb 10.5 vs 9.5 gr% (p=0.6), Neutrophils 2.4 vs 1.9x10^9/l (p=0.4) and platelets 42 vs 36 x10^9/l (p=0.3). The actuarial survival at 4 years is 72% in group A vs 67% in group B (p=0.3). An additional finding of this study is a strong age effect, with an actuarial 4 year survival of 81% in patients aged 0–20 , 80% in patients aged 21–40 and 34% in patients over 40 (p=0.0002). This correlated with the inability of older patients to increase their white blood cell (WBC) counts above 5x10^9/L, during G-CSF treatment. In a multivariate COX analysis patient age and highest WBC counts during G-CSF, were both significant predictors of survival. Interpretation and conclusions. Increasing the dose of G-CSF does not appear to reduce early deaths, does not improve peripheral blood counts nor survival, and may reduce the response rate in patients with SAA receiving ALG and CyA. Older age and failure to improve WBC are negative predictors of survival.

Description: Abstract 4195 Directed family cord blood (DCB) storage provides hemopoietic stem cell source for transplantation (HSCT) for families with an existing or a potentially future recipient with HSCT curable disease (D). The National CB Banks Network in Italy (ITCBN) has a leading role in providing public DCB service for high-risk families, in compliance to GITMO directives for eligibility criteria (HSCT curable D: malignant MD, non MD, inherited ID). To provide best cost-effective practices recommendations it is important to report on DCB procedures and HSCT rate (HSCT-R) among public Banks. By 12.12.2008 almost 1800 DCB units were stored in 18 Italian Banks and 104 (9%) issued for HSCT. The present survey aims at summarizing the over 15 yrs DCB experience among 5 ITCBN Banks active since 1997 (range 1990-1997), and including 670 DCB units. Results Preliminary analysis reports a 94% overall compliance to eligibility criteria directives, and overall HSCT- R for an alive sibling of 12% (63/522); the 63 HSCT were 97% matched, for curing ID in 84% and with 72 % overall survival outcome. Different policies among Banks were compared (Bank vs others: 1) eligibility criteria distribution : Bank PV06 DCB for MD

Description: Background: Thrombophilia in children is characterized by hypercoagulability and increased frequency of thrombotic events (Young G, et al. Circulation. 2008;118:1373-1378; Kenet G, et al. Circulation. 2010;121:1838-1847). Recently, phase IIb/III clinical trials in children with venous thromboembolism (VTE) have reported the non-inferiority of dabigatran etexilate (DE) versus standard of care (SOC) for the treatment of acute VTE (Albisetti M, et al. ISTH 2019, Abstract OC 57.3), and a favorable safety profile for DE in secondary VTE prevention in children with persistent VTE risk factor(s) (Brandão LR, et al. Blood. 2020;135:491-504). Aims: To perform a subgroup analysis evaluating the efficacy and safety of DE for the treatment and secondary prophylaxis of VTE in children with thrombophilia in the phase IIb/III DE clinical trials. Methods: In the open-label, phase IIb/III DIVERSITY trial (NCT01895777), children aged from birth to 〈 18 years (yrs) with an objectively confirmed VTE diagnosis (by imaging studies) initially treated with unfractionated heparin or low-molecular-weight heparin were randomized (2:1) to receive up to 3 months of DE or SOC. Primary composite efficacy endpoint: complete thrombus resolution and freedom from VTE recurrence, or VTE-related death. Safety endpoints included bleeding events (BEs). The open-label, phase III, secondary VTE prevention trial (NCT02197416) treated children aged from 〉 3 months to 〈 18 yrs with DE for up to 12 months or less, if the identified VTE clinical risk factor resolved. Eligible children had an objectively confirmed diagnosis of VTE treated with SOC for ≥ 3 months, or had completed DE or SOC treatment in DIVERSITY and had an unresolved clinical VTE risk factor requiring further anticoagulation. Primary endpoints included VTE recurrence and BEs. Thrombophilia status was confirmed according to the definitions used by the local experts. Results: In DIVERSITY, 23.2% of children had thrombophilia; demographics were comparable to the overall population, although they were slightly older (mean [standard deviation] age 13.2 [4.9] vs 11.1 [6.1] years in the overall population; p = 0.005). In children with thrombophilia, DE was found to be non-inferior to SOC for the primary endpoint (similar to the overall population), and more children treated with DE achieved the composite primary endpoint than with SOC (SOC 21.7% vs DE 35.9%; Mantel-Hänszel-weighted difference in rates for SOC minus DE [90% CI] −0.14 [−0.32 to 0.05]; p for non-inferiority = 0.0014), similar to the overall population (Table). Regardless of treatment, VTE recurrence appeared higher in children with thrombophilia than in the overall population, with numerically fewer VTE recurrences reported by children with thrombophilia treated with DE (7.7%) versus SOC (21.7%), although this was not significantly lower (p = 0.13). Numerical differences in residual thrombotic burden between SOC vs DE seen in the overall population appeared to be amplified in children with thrombophilia. Numerically fewer children with thrombophilia treated with DE reported thrombus progression (SOC 13.0% vs DE 5.1%) or stabilization (21.7% vs 10.3%), while more reported partial (34.8% vs 43.6%) or complete thrombus resolution (21.7% vs 35.9%). In the thrombophilia subgroup, BEs appeared to be lower in children treated with DE (SOC 26.1% vs DE 17.9%), while in the overall population BEs with SOC and DE were comparable. In the secondary VTE prevention trial, children with thrombophilia were also slightly older versus the overall population (mean [standard deviation] age 14.1 [3.6] vs 12.8 [4.6] yrs; p = 0.006). In this larger subgroup of children, rates of recurrent VTE at 12 months appeared to be higher in the thrombophilia group (2.8%) compared to the overall population (1.4%) (Table), with BEs largely comparable (27.4% and 22.5%, respectively). Conclusions: Unsurprisingly, numerically more children with thrombophilia appeared to report VTE recurrence, and in DIVERSITY thrombus progression/stabilization also seemed higher compared with the overall population. Compared with the overall populations, these subgroup analyses showed consistent results for DE in children with acute VTE and thrombophilia in the DIVERSITY trial, along with a favorable safety profile of DE for secondary VTE prevention. Disclosures Brandao: Boehringer Ingelheim: Other: Member of a paediatric expert working group. Tartakovsky:Boehringer Ingelheim: Current Employment. Albisetti:Boehringer Ingelheim: Other: Member of a paediatric expert working group; Daiichi Sankyo: Membership on an entity's Board of Directors or advisory committees. Bomgaars:Boehringer Ingelheim: Other: Member of a paediatric expert working group. Chalmers:CSL Behring: Honoraria; Shire/Takeda: Honoraria; Boehringer Ingelheim: Other: Member of a paediatric expert working group; Grifols: Honoraria; Roche: Honoraria; Sobi: Honoraria; Bristol-Myers Squibb: Honoraria. Mitchell:Boehringer Ingelheim: Other: Member of a paediatric expert working group. Luciani:Boehringer Ingelheim: Other: Member of a paediatric expert working group. Lvova:Boehringer Ingelheim: Honoraria. Simetzberger:Boehringer Ingelheim: Current Employment. Sun:Boehringer Ingelheim: Current Employment. Gergei:Boehringer Ingelheim: Current Employment. Brueckmann:Boehringer Ingelheim: Current Employment. Halton:Boehringer Ingelheim: Other: Member of a paediatric expert working group. OffLabel Disclosure: dabigatran etexilate in paediatric VTE

Description: Introduction Asplenic patients are at high risk of potentially fatal invasive infections, such as sepsis, meningitis, and pneumonia. It has been shown that infection from influenza viruses can precede or increase the risk of bacterial infection and of serious complications of the underlying disease. International and national guidelines recommend annual influenza vaccination in asplenic subjects. Following the Covid-19 pandemic, the major government and medical-scientific institutions in the US and in Europe have been planning how to contain infection during the 2020-2021 influenza season. Extending influenza vaccination is the safest and most effective way to reduce the circulation of influenza virus and to promote the correct diagnosis and management of suspected cases of SARS-CoV-2. Influenza vaccination also reduces complications associated with the underlying disease and visits to Emergency Units. Our study aims to evaluate influenza vaccination in a large population of asplenic patients and explore the main causes for non-vaccination to identify critical areas for improvement in the vaccination programme in these at-risk patients for the 2020-2021 influenza season. Methods The Italian Network of Asplenia (INA) is made up of 88 doctors working in 50 clinical centers in 27 cities and 16 of the 20 regions of Italy. It aims to build a large, prospective cohort of asplenic patients throughout Italy through which to study the interaction between asplenia and its associated underlying conditions, collecting precise, accurate data also in cases of rarer diseases. The study also aims to improve the quality of healthcare for this at-risk population. The number of patients enrolled in the Network who had had at least one dose of influenza vaccine at the time of diagnosis of asplenia was retrieved from the INA database. All participating centers were asked to answer a questionnaire to report the main obstacles for influenza vaccination. Results At 1st August 2020, 1,670 patients had been enrolled in the INA (783 females; 887 males). All underlying causes of asplenia are shown in Table 1. Only 466 (28%) patients had had at least one influenza vaccination, while 1,204 (72%) had never been vaccinated since diagnosis of asplenia. Thirty-five (70%) of the 50 centers answered the questionnaire. Main causes of non-vaccination were physicians' ambivalence concerning vaccination and patients' inadequate awareness or logistical problems. Conclusions These data show very low seasonal influenza vaccination cover even though asplenic patients are considered at-risk of complications associated with infection from influenza viruses. Since the 2020-2021 influenza season could see influenza viruses in circulation with SARS-CoV-2, influenza vaccination must be expanded as widely as possible, in particular to subjects of all ages at high risk. These results reveal important areas of concern in the management of asplenic patients and the need to improve the quality of information to physicians and patients alike. The INA co-ordinating center will launch a campaign to provide information and organize ad hoc meetings to widen influenza vaccination coverage in asplenic patients and reduce the pressure on the national health service during the next influenza season. Disclosures Forni: Novartis: Membership on an entity's Board of Directors or advisory committees. Colombatti:Addmedica: Membership on an entity's Board of Directors or advisory committees; Global Blood Therapeutics: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees. Giona:Sanofi Genzyme: Research Funding, Speakers Bureau; Takeda: Speakers Bureau; Novartis: Research Funding. Ferrero:Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; EUSA Pharma: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Research Funding, Speakers Bureau; Servier: Speakers Bureau. Perrotta:Novartis: Consultancy, Research Funding, Speakers Bureau. Casale:Novartis: Membership on an entity's Board of Directors or advisory committees.