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Hereditary factor X (FX) deficiency (FXD) is a rare autosomal recessive bleeding disorder. Plasma-derived FX (pdFX) is a high-purity FX concentrate approved in the United States and Europe for the treatment and prophylaxis of bleeding episodes and for peri-operative management in patients with hereditary FXD (HFXD).To review pharmacokinetic dosing, efficacy, and safety data for pdFX as routine prophylaxis for HFXD.Summary of the published pharmacokinetic and safety data from TEN01, TEN02, TEN05, and real-world publications of pdFX for prophylaxis.Pharmacokinetic modelling data from the phase 3 TEN01 study supported administration of pdFX 25 IU/kg twice weekly for routine prophylaxis in adolescents/adults (aged ≥12 years). Results from nine paediatric patients in the phase 3 TEN02 study and eight adolescents/adults (aged ≥12 years) in the retrospective data-collection TEN05 study, along with real-world evidence, showed that routine prophylaxis with pdFX ≈40 IU/kg twice weekly in patients aged 12 years and pdFX ≈25 IU/kg twice weekly in patients aged ≥12 years was effective in bleeding prevention.pdFX was well tolerated in clinical studies, with no new safety signals identified during routine prophylactic use. Based on current evidence, it is recommended that routine prophylaxis with pdFX be initiated at 25 IU/kg twice weekly in adults/adolescents ≥12 years of age, and at a dosage of 40 IU/kg twice weekly in children 12 years of age. Thereafter, FX levels should be closely monitored, and dosages should be adjusted according to clinical response and to maintain trough levels ≥5 IU/dl.

Haemophilia B (HB) is less well studied than haemophilia A (HA); despite similarities between the two inherited bleeding disorders, important differences remain that require further research.B-Natural is a multi-centre, prospective, observational study of HB, designed to increase understanding of clinical manifestations, treatment, quality-of-life (QoL), inhibitor development, immune tolerance induction (ITI) outcome, renal function and create a biorepository for future investigations.Participants include sibling pairs/groups without a current/history of inhibitors and singletons or siblings with a current/history of inhibitors followed for six months. Demographics, medical, social history and treatment were recorded. A physical examination including joint range of motion (ROM) was performed; QoL was assessed. Samples were collected for F9 gene mutation, HLA typing, non-inhibitory antibodies and renal function testing.Twenty-four centres enrolled 224 individuals from 107 families including 29 with current/history of inhibitors. Of these, 68, 30.4%, had severe (1% FIX level of normal); 114, 50.9%, moderate (1%-5%); and 42, 18.8%, mild (5-40%) disease. At enrolment, 53.1% had 50 + exposure days to exogenous FIX. Comparison of joint scores showed significant (P .05) differences between those with severe (with/without inhibitors), and those with moderate/mild disease. The majority with severe disease, 80.0% with current/history of inhibitors and 64.3% of those without, were treated with prophylaxis.B-Natural provides data supporting an increased understanding of HB and its impact throughout life. The need for optimal disease control to normalize physical and psychosocial outcomes is underscored, and further analyses will contribute to an increased understanding of critical issues in HB.

Preventing factor VIII (FVIII) inhibitors following replacement therapies with FVIII products in patients with hemophilia A remains an unmet medical need. Better understanding of the early events of evolving FVIII inhibitors is essential for risk identification and the design of novel strategies to prevent inhibitor development. The Hemophilia Inhibitor Previously Untreated Patients (PUPs) Study (HIPS; www.clinicaltrials.gov #NCT01652027) is the first prospective cohort study to evaluate comprehensive changes in the immune system during the first 50 exposure days (EDs) to FVIII in patients with severe hemophilia A. HIPS participants were enrolled prior to their first exposure to FVIII or blood products (“true PUPs”) and were evaluated for different immunological and clinical parameters at specified time points during their first 50 EDs to a single source of recombinant FVIII. Longitudinal antibody data resulting from this study indicate that there are 4 subgroups of patients expressing distinct signatures of FVIII-binding antibodies. Subgroup 1 did not develop any detectable FVIII-binding immunoglobulin G (IgG) antibodies. Subgroup 2 developed nonneutralizing, FVIII-binding IgG1 antibodies, but other FVIII-binding IgG subclasses were not observed. Subgroup 3 developed transient FVIII inhibitors associated with FVIII-binding IgG1 antibodies, similar to subgroup 2. Subgroup 4 developed persistent FVIII inhibitors associated with an initial development of high-affinity, FVIII-binding IgG1 antibodies, followed by IgG3 and IgG4 antibodies. Appearance of FVIII-binding IgG3 was always associated with persistent FVIII inhibitors and the subsequent development of FVIII-binding IgG4. Some of the antibody signatures identified in HIPS could serve as candidates for early biomarkers of FVIII inhibitor development.

BACKGROUND Congenital factor X deficiency (FXD) is a rare bleeding disorder that often presents with severe bleeding in the neonatal period. Long-term prophylaxis with infusions of FX-containing products is recommended in patients with FXD and a personal or family history of severe bleeding. A plasma-derived FX concentrate (pdFX) is approved for on-demand and prophylactic therapy in adults and children with FXD. The safety and efficacy of pdFX has been demonstrated in patients

Haemophilia is an inherited bleeding disorder in which the haemostatic defect results from deficiency of coagulation factor VIII (FVIII) in haemophilia A or factor IX (FIX) in haemophilia B. Traditional treatments for haemophilia have largely worked by directly replacing the missing coagulation factor, but face challenges due to the short half-life of FVIII and FIX, the need for frequent intravenous access and development of neutralising antibodies to coagulation factors (inhibitors). Recent advances in haemophilia therapy have worked to eliminate these challenges. Half-life extension of factor concentrates has lengthened the time needed between infusions, enhancing quality of life. Subcutaneous administration of therapeutics utilising alternative mechanisms to overcome inhibitors have expanded the options to prevent bleeding. Finally, initial successes with gene therapy offer a cautious hope for durable cure. In the present review, we will discuss currently available treatments, as well as highlight therapeutics in various stages of clinical development for the treatment of haemophilia A and B. In this review, we present therapies that are currently clinically available and highlight therapeutics that are in various stages of clinical development for the treatment of haemophilia A and B.

The North American Pediatric Aplastic Anemia Consortium (NAPAAC) is a group of pediatric hematologist-oncologists, hematopathologists, and bone marrow transplant physicians from 46 institutions in North America with interest and expertise in aplastic anemia, inherited bone marrow failure syndromes, and myelodysplastic syndromes. The NAPAAC Bone Marrow Failure Diagnosis and Care Guidelines Working Group was established with the charge of harmonizing the approach to the diagnostic workup of aplastic anemia in an effort to standardize best practices in the field. This document outlines the rationale for initial evaluations in pediatric patients presenting with signs and symptoms concerning for severe aplastic anemia.

Mullins, Eric/0000-0002-1544-9068; Chowdary, Pratima/0000-0002-6690-8586 WOS:000543654900001 PubMed ID: 32597029 Introduction Previous studies reported the efficacy and safety profile of extended half-life PEGylated recombinant factor VIII (FVIII) rurioctocog alfa pegol (TAK-660, SHP660, BAX 855) in preventing bleeding in haemophilia A patients. Aim This study evaluated long-term safety and efficacy of rurioctocog alfa pegol for prophylaxis and treatment of bleeding in previously treated children and adults. Methods In this phase 3b, prospective, open-label, multicentre study (NCT01945593), eligible patients

Fifteen patients with moderately severe to severe hemophilia B (factor IX [FIX] activity ≤2%) were treated with fidanacogene elaparvovec at a dose of 5e11 vg/kg as part of a phase 1/2a study. The study was 52 weeks in duration, after which patients were eligible to enroll in the long-term follow-up (LTFU) study of up to 5 years. All 15 patients completed the phase 1/2a study, and 14 patients were subsequently enrolled in the LTFU study. At the time of the data cut (December 2020), 13 patients were enrolled in the LTFU study, with follow-up ranging from >2.5 years to >5 years following vector administration. Over this period of time, fidanacogene elaparvovec remained generally well tolerated. As reported previously, 3 patients were treated with corticosteroids within the first 6 months of the phase 1/2a study. No patients have required treatment or re-treatment with corticosteroids in the LTFU study. There were no serious adverse events (SAEs) in the phase 1/2a study, and 3 patients reported SAEs in the LTFU study, none of which were considered treatment related. No patient developed an inhibitor or had a thrombotic event. No patients have developed hepatic masses or significant elevations in alpha-fetoprotein (AFP). Annual liver ultrasounds revealed only hepatic steatosis in one patient. Mean FIX activity levels by year remain in the mild hemophilia severity range: 22.8%, year 1 (n=15); 25.4%, year 2 (n=14); 22.9%, year 3 (n=14); 24.9%, year 4 (n=9); and 19.8%, year 5 (n=7) when evaluated centrally using the ACTIN/FSL one-stage assay. These levels have been associated with mean annualized bleeding rates ranging from 0-0.9 over the course of follow-up, and no patients have resumed FIX prophylaxis. Four patients have undergone 6 surgical procedures during the LTFU study, 4 elective and 2 emergent. There were no bleeding complications with these procedures, and the 2 emergent procedures (appendectomy and lumbar discectomy) were performed without the need of additional FIX. Overall, this represents the largest cohort of hemophilia B patients with a duration of follow-up up to 5 years following treatment with an adeno-associated virus gene therapy expressing a highly active variant of FIX. Fidanacogene elaparvovec remains generally well tolerated over a period up to 5 years postinfusion. While encouraging, more long-term data in a larger cohort of patients are needed to further characterize the safety and durability of fidanacogene elaparvovec, which is under way in an ongoing phase 3 study. Disclosures Samelson-Jones: Pfizer: Consultancy, Research Funding; Spark: Research Funding. Sullivan: Genentech: Membership on an entity's Board of Directors or advisory committees; Bayer: Membership on an entity's Board of Directors or advisory committees; Pfizer Inc.: Membership on an entity's Board of Directors or advisory committees; Biomarin: Membership on an entity's Board of Directors or advisory committees; Octapharma: Membership on an entity's Board of Directors or advisory committees. Rasko: Imago: Consultancy; Cynata: Honoraria, Speakers Bureau; Gene Technology Technical Advisory Board: Membership on an entity's Board of Directors or advisory committees; NHMRC Mitochondrial Donation Expert Working Committee: Membership on an entity's Board of Directors or advisory committees; Australian Cancer Research: Membership on an entity's Board of Directors or advisory committees; Cure the Future Foundation: Membership on an entity's Board of Directors or advisory committees; FSHD Global Research Foundation: Membership on an entity's Board of Directors or advisory committees; Australian Government: Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Pfizer Inc: Honoraria, Speakers Bureau; Glaxo-Smith-Kline: Honoraria, Speakers Bureau; Spark: Honoraria, Speakers Bureau; Takeda: Honoraria, Speakers Bureau; bluebird bio: Honoraria, Speakers Bureau; Genea: Current equity holder in publicly-traded company; Celgene: Honoraria, Speakers Bureau. Giermasz: BioMarin: Consultancy, Research Funding; Genentech/Roche: Consultancy, Research Funding, Speakers Bureau; Pfizer: Consultancy; Bayer: Consultancy; ATHN: Consultancy; NovoNordisk: Consultancy; UniQure: Consultancy, Research Funding; Sanofi Genzyme: Consultancy; Bioverativ/Sanofi: Consultancy, Research Funding, Speakers Bureau; Sangamo Therapeutics,: Research Funding. George: CSL Behring: Consultancy; Bayer: Consultancy; Avrobio: Other: Data Safety Monitoring Committee . Ducore: Octapharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Shire: Consultancy, Honoraria; Bayer: Consultancy, Honoraria, Speakers Bureau; HEMA Biologics: Consultancy, Honoraria. Teitel: Pfizer: Consultancy, Research Funding; Spark: Research Funding; Bayer: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Novo Nordisk: Consultancy; Octapharma: Consultancy; CSL Behring: Consultancy. McGuinn: Biogen: Research Funding; Roche/Genentech: Research Funding; Shire/Baxalta: Consultancy, Research Funding; Spark: Research Funding. O'Brien: Pfizer Inc.: Current Employment, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Winburn: Pfizer Inc.: Current Employment, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Smith: Pfizer Inc.: Current Employment, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Chhabra: Pfizer Inc.: Current Employment, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Rupon: Pfizer Inc.: Current Employment, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company.

Introduction: Among the most challenging complications of hemophilia A is inhibitor formation. A T-cell dependent B-cell response to exogenous factor VIII (FVIII), inhibitors result in a high burden of disease, with poorly controlled bleeding, twice the hospitalizations, 10-fold the cost, and 3.5-fold the mortality of non-inhibitor patients. Thus, a major goal of hemophilia management is to prevent and eradicate inhibitors. With the availability of novel therapies, including eloctate, a recombinant Fc-fusion protein (rFVIII-Fc) which induces regulatory T cells to promote FVIII tolerance, and emicizumab, a bispecific monoclonal FVIII mimetic, we designed the INHIBIT Clinical Trials Platform (X01HL143024), Fig.1. The platform is composed of two linked randomized phase III trials, the Inhibitor Prevention Trial (NCT04303559), comparing rFVIII-Fc vs emicizumab prophylaxis to prevent inhibitors, and the Inhibitor Eradication Trial (NCT04303572), comparing rFVIII-Fc immune tolerance induction (ITI) plus emicizumab vs rFVIII-Fc ITI alone to eradicate inhibitors. The platform uses adaptive design to incorporate historical data (Bayesian priors) on inhibitor formation to increase power and promote efficient use of rare data. Yet, there is equipoise regarding the optimal approach to inhibitor prevention and eradication, and, as clinical practice is changing, we aimed to test the feasibility of the INHIBIT trial design. Methods: To establish design feasibility, we conducted interviews with 30 hemophilia treatment center (HTC) physicians participating in the INHIBIT trials, to determine prophylaxis and tolerance regimens they prescribe and perceived barriers to the INHIBIT trials design. A 4-question survey was subsequently emailed to these physicians to ascertain the initial prophylaxis regimens they prescribe in previously untreated patients (PUPs) with severe hemophilia A, and the initial immune tolerance induction (ITI) they prescribe in high-responding inhibitor patients with severe hemophilia A; if new inhibitors had been observed during emicizumab prophylaxis, and willingness to participate in post-trial surveillance. Results: In interviews, HTC physicians indicated the issues that influenced choice of prophylaxis/ ITI regimen were patient preference, family history of inhibitors, infusion frequency, IV access, port requirement, and family fatigue. In the absence of clinical trials data in PUPs, there was general agreement that emicizumab prophylaxis, with it simpler subcutaneous (SQ) administration, might delay or potentially prevent inhibitors. Survey findings in Table 1 indicated 75% of physicians prescribe extended half-life (EHL) FVIII in a once-weekly prophylaxis regimen, as planned in the Prevention Trial, despite the persistent 27% inhibitor rate (ALong PUPs Trial, Königs et al, ISTH 2020) and potential risks with port use. There was support for the 1:3 preferential randomization to emicizumab in the Prevention Trial due to the simpler SQ route, despite concern it might delay rather than prevent inhibitor formation, although no inhibitors were reported by physician survey with emicizumab use alone. There was also concern that breakthrough bleeds requiring FVIII during emicizumab prophylaxis, might lead to immune activation and inhibitor formation. There was strong agreement, however, in 29 (97%) of physicians to participate in post-trial surveillance for long-term inhibitor outcomes. FVIII ITI was considered essential to eradicate inhibitors, despite the intensity of the infusion regimen. Notably, 60% prescribe emicizumab with FVIII ITI, as planned in the Eradicate Trial, although the every-other-day infusion was considered a potential barrier to participation. Omitting FVIII ITI was not favored due to the risk of inhibitor anamnesis if FVIII treatment was subsequently required for surgery or acute hemorrhages. Despite these concerns, there was agreement to participate in the trials. Discussion: Physician interviews and surveys confirm there is heterogeneity in current hemophilia clinical practice, specifically in initial prophylaxis regimens and in initial immune tolerance regimens, including agent choice and duration. However, there is physician consensus with the INHIBIT trial aims and with the proposed INHIBIT trial regimens to prevent and eradicate inhibitors. Disclosures Ragni: Bioverativ: Membership on an entity's Board of Directors or advisory committees, Research Funding; Alnylam/Sanofi: 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, Research Funding; ATHN: Research Funding; Sangamo: Research Funding. Seaman:Bayer: Consultancy; Genentech: Consultancy; Spark Therapeutics: Consultancy; Takeda: Consultancy. Acharya:Novonordisk: Membership on an entity's Board of Directors or advisory committees; BPL: Membership on an entity's Board of Directors or advisory committees; Bayer Pharma Inc.: Research Funding. Wheeler:Novo Nordisk: Membership on an entity's Board of Directors or advisory committees; Biomarin: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; UniQure: Membership on an entity's Board of Directors or advisory committees. Tarango:Takeda/Shire: Honoraria, Other; Bayer: Consultancy, Other; Sanofi: Honoraria, Other. Dunn:ATHN: Research Funding; Spire: Honoraria; Medscape: Honoraria; World Federation of Hemophilia USA: Membership on an entity's Board of Directors or advisory committees; Takeda: Research Funding; BioMarin: Research Funding; uniQure: Consultancy; Genentech, Inc.: Consultancy; Nationwide Children's Hospital: Current Employment. Kulkarni:Sanofi/ Bioverativ, Bayer, Biomarin, Shire/Takeda, Novo Nordisk, Freeline: Other: clinical trial research grants ; Bioverativ/Sanofi, BPL, Genentech, Kedrion, Novo Nordisk, Octapharma, Pfizer, Takeda, Catalyst Bioscience Bayer: Membership on an entity's Board of Directors or advisory committees. Ahuja:Genentech: Consultancy, Honoraria; Sanofi Genzyme: Consultancy, Honoraria; XaTek, Inc.: Consultancy, Patents & Royalties, Research Funding. Chitlur:Takeda: Honoraria; Biovertiv: Honoraria; Agios Pharmaceuticals: Research Funding; Pfizer: Honoraria; Novo Nordisk: Consultancy, Honoraria. Pipe:Apcintex, Bayer, BioMarin, Catalyst Biosciences, CSL Behring, HEMA Biologics, Freeline, Novo Nordisk, Pfizer, F. Hoffmann-La Roche Ltd/Genentech, Inc., Sangamo Therapeutics, Sanofi, Takeda, Spark Therapeutics, uniQure: Consultancy; Siemens: Research Funding; Medical and Scientific Advisory Council to the National Hemophilia Foundation; Medical Advisory Board to World Federation of Hemophilia: Membership on an entity's Board of Directors or advisory committees. Malec:Sanofi Genzyme: Consultancy, Research Funding, Speakers Bureau; CSL: Consultancy; Takeda: Consultancy; Bayer: Consultancy; SOBI: Consultancy. Leissinger:Bayer: Consultancy; Kedrion: Consultancy; CSL Behring: Membership on an entity's Board of Directors or advisory committees; Genentech: Consultancy; HEMA Biologics: Consultancy; Takeda: Consultancy; Uniqure: Consultancy; Spark: Consultancy. Carpenter:Hemostasis & Thrombosis Research Society: Membership on an entity's Board of Directors or advisory committees; American Academy of Pediatrics: Other: PREP Heme/Onc editorial board; Kedrion: Honoraria; Novo Nordisk: Honoraria; Genentech, Inc.: Honoraria; American Thrombosis and Hemostasis Network: Membership on an entity's Board of Directors or advisory committees; CSL Behring: Research Funding; Shire: Research Funding. Knoll:NovoNordisk: Membership on an entity's Board of Directors or advisory committees. Wang:Bioverativ Inc: Honoraria; Bayer: Honoraria; CSL Behring: Honoraria; Biomarin: Honoraria; Genentech: Honoraria; Takeda: Honoraria. Young:Genentech/Roche, Grifols, and Takeda: Research Funding; Bayer, CSL Behring, Freeline, UniQure: Consultancy; BioMarin, Freeline, Genentech/Roche, Grifols, Kedrion, Novo Nordisk, Sanofi Genzyme, Spark, Takeda, and UniQure: Honoraria. Thornburg:Genentech: Speakers Bureau; Spark Therapeutics: Consultancy; Bluebird Bio: Consultancy; Ironwood Pharmaceuticals: Consultancy, Other: Data Safety Monitoring Board; American Thrombosis and Hemostasis Network: Research Funding; Sanofi Genzyme: Consultancy, Other: Data Safety Monitoring Board, Research Funding; NovoNordisk: Research Funding; Biomarin: Consultancy, Speakers Bureau; Bayer Pharmaceuticals: Research Funding; National Hemophilia Foundation: Membership on an entity's Board of Directors or advisory committees, Research Funding. Lucas:CRISPR Therapeutics: Membership on an entity's Board of Directors or advisory committees. Hwang:Shire: Honoraria; Takeda: Honoraria.

The prevention of bleeding with adequately sustained levels of clotting factor, after a single therapeutic intervention and without the need for further medical intervention, represents an important goal in the treatment of hemophilia.We infused a single-stranded adeno-associated viral (AAV) vector consisting of a bioengineered capsid, liver-specific promoter and factor IX Padua (factor IX-R338L) transgene at a dose of 5×10No serious adverse events occurred during or after vector infusion. Vector-derived factor IX coagulant activity was sustained in all the participants, with a mean (±SD) steady-state factor IX coagulant activity of 33.7±18.5% (range, 14 to 81). On cumulative follow-up of 492 weeks among all the participants (range of follow-up in individual participants, 28 to 78 weeks), the annualized bleeding rate was significantly reduced (mean rate, 11.1 events per year [range, 0 to 48] before vector administration vs. 0.4 events per year [range, 0 to 4] after administration; P=0.02), as was factor use (mean dose, 2908 IU per kilogram [range, 0 to 8090] before vector administration vs. 49.3 IU per kilogram [range, 0 to 376] after administration; P=0.004). A total of 8 of 10 participants did not use factor, and 9 of 10 did not have bleeds after vector administration. An asymptomatic increase in liver-enzyme levels developed in 2 participants and resolved with short-term prednisone treatment. One participant, who had substantial, advanced arthropathy at baseline, administered factor for bleeding but overall used 91% less factor than before vector infusion.We found sustained therapeutic expression of factor IX coagulant activity after gene transfer in 10 participants with hemophilia who received the same vector dose. Transgene-derived factor IX coagulant activity enabled the termination of baseline prophylaxis and the near elimination of bleeding and factor use. (Funded by Spark Therapeutics and Pfizer; ClinicalTrials.gov number, NCT02484092 .).

INTRODUCTION Radionuclide synovectomy/synoviorthesis (RS) to manage proliferative synovitis in persons with bleeding disorders has been utilized for decades; however, aggregate US results are limited. AIM To determine the prevalence of RS utilization, patient and procedure related demographics and functional outcomes in United States haemophilia treatment centres (HTCs). The ATHNdataset includes US patients with bleeding disorders who have authorized the sharing of their demographic and clinical information for research. METHODS We performed a multi-institutional, observational cohort study utilizing this dataset through 2010. Cases treated with RS procedure were compared to controls within the dataset. Standard template for data collection included patient and procedure related demographics as well as functional outcomes including range of motion (ROM) of the affected joint. Normative age- and sex-matched control ROM was obtained from published data. RESULTS In the ATHNdataset there were 19 539 control-patients and 196 case-patients treated with RS. Patients with severe haemophilia were more likely to have had RS compared to those with mild/moderate haemophilia, although the proportion of RS performed was similar between severe HA and HB. Inhibitory antibodies, HIV and hepatitis C infection were significantly more common in cases. There were 362 RS procedures captured with 94 cases having >1 RS procedures. CONCLUSIONS Right-sided joint procedures were more prevalent than left-sided procedures. Overall, case-patients had worse joint ROM compared to control-patients and published normative values. Geographically, there was regional variation in RS utilization, as the Southeast region had the largest percent of case-patients.

This chapter describes the current understanding of a wide variety of platelet pathology, including thrombocytopenia, thrombocytosis, qualitative platelet disorders, and diagnostic approaches to these problems. Autoimmune and alloimmune neonatal thrombocytopenia, immune thrombocytopenia in the older child, as well as other acquired causes of thrombocytopenia including thrombotic thrombocytopenia purpura (inherited and acquired) are described. Classical therapeutics and new agents like the thrombopoietics are reviewed. The discussion of thrombocytosis includes secondary causes of thrombocytosis and familial and hereditary thrombocytosis. Qualitative platelet disorders including various inherited disorders of platelet function and secondary causes of platelet impairment (e.g., drugs) are described. It also includes a section focused on diagnostic tests for platelet function.

Background: Patients with severe hemophilia A experience substantial morbidity and mortality due to frequent spontaneous and traumatic bleeding episodes, especially in joints. Prophylaxis with standard half-life factor VIII (FVIII) is the standard of care to prevent bleeds. Extended half-life products benefit patients by reducing the number of infusions without impacting the treatment efficacy. Methods: This phase 3b, prospective, open-label, multicenter, continuation study (NCT# 01945593) investigated the safety and efficacy of a PEGylated recombinant FVIII with an extended half-life, rurioctocog alfa pegol (SHP660, BAX 855, ADYNOVATE®, Shire, Lexington, MA, USA), for prophylaxis and treatment of bleeding in patients with severe hemophilia A (FVIII Results: The study began in October 2013 and completed in March 2018. Overall, 216 patients receiving prophylaxis were eligible and included in the safety/full analysis dataset (≥1 dose received). Of these, 215 were male, the mean (SD) age at enrollment was 22.8 (15.7) years, the mean (SD) number of documented previous rurioctocog alfa pegol exposure days was 57.0 (39.6), the total ABR over 3-6 months prior to enrollment in the continuation study (including patients naïve to rurioctocog alfa pegol or receiving on-demand or prophylactic treatment with rurioctocog alfa pegol) was mean (SD) 4.7 (12.6), median (range) 0.0 (0-69). Most patients (206; 95.4%) had participated in a previous rurioctocog alfa pegol study. Overall, 215 patients received ≥1 dose in the FD regimen and 25 received ≥1 dose in the PK regimen. These patients received a mean (SD) of 1.72 (0.29) and 2.11 (0.61) prophylactic infusions per week, respectively, with a mean (SD) dose per infusion of 51.15 (8.11) IU/kg and 52.14 (17.03) IU/kg, respectively. None of the patients developed a confirmed FVIII inhibitor in this study and only 1 treatment-related allergic or hypersensitivity reaction (a nonserious mild AE) was reported. Nonserious AEs assessed by the investigators to be related to treatment occurred in 11/216 (5.1%) patients. Serious AEs (SAEs) occurred in 33 (15.3%) patients; there were no SAEs assessed by the investigators to be related to treatment. Descriptive statistics on spontaneous, joint, and total ABR by prophylactic regimen are shown in the Table. The overall total ABR in all patients was mean (SD) 2.5 (3.1), median (range) 1.6 (0.0-19.5). Overall hemostatic efficacy was rated as good or excellent in 88.5% of all bleeds and 89.4% of all bleeds were treated with 1 or 2 infusions. Conclusions: These results show that in previously treated patients with severe hemophilia A, rurioctocog alfa pegol prophylaxis in FD- and PK-tailored regimens was well tolerated and effective. None of the patients developed FVIII inhibitory antibodies, and a decrease in mean total ABR was reported in these patients compared with baseline. Disclosures Mullins: Shire: Honoraria, Membership on an entity's Board of Directors or advisory committees. Konkle:Genentech: Consultancy; CSL Behring: Consultancy; Gilead: Consultancy; Pfizer: Research Funding; Spark: Consultancy, Research Funding; BioMarin: Consultancy; Bioverativ: Research Funding; Shire: Research Funding; Sangamo: Research Funding. McGuinn:CSL Behring: Consultancy; BioMarin: Consultancy; Bioverativ: Membership on an entity's Board of Directors or advisory committees, Research Funding; Spark: Consultancy, Research Funding; Genentech: Consultancy; Shire: Research Funding; Pfizer: Research Funding. Engl:Shire: Employment, Equity Ownership. Tangada:Shire: Employment, Equity Ownership.

Background and objectives FVIII inhibitors remain the major complication of replacement therapy in hemophilia A. Why some patients develop inhibitors whereas others do not is poorly understood. The Hemophilia Inhibitor PUP Study (HIPS, clinicaltrials.gov NCT01652027), a prospective multicenter observational study, aim to identify early immune biomarkers which predict inhibitor development in previously untreated patients (PUPs) with severe hemophilia A. Such biomarkers would facilitate early risk identification and the initiation of potential immune intervention strategies. Previously we reported time-resolved antibody data for the first 15 patients who completed antibody analysis (Gangadharan 2017). Here we present data from all 25 patients enrolled in HIPS, identifying four distinct patient subgroups based on their unique antibody signatures. We also summarize data for F8 mutations and longitudinal data of circulating immune cells such as FoxP3+ T cells (Tregs), Th17 cells, and granulysin+ cells. Methods FVIII inhibitor testing (Nijmegen method, performed in the central laboratory Medical University of Vienna) and antibody analytics were assessed prior to first exposure, 7-9 days after exposure day (ED) 1 and 5-7 days after EDs 5, 10, 20, 30, 40, and 50. FVIII-specific advanced antibody analytics were performed using methodology described by Whelan 2013 and Hofbauer 2015. FVIII mutational analysis was performed at Bloodworks Northwest, Seattle. Longitudinal epigenetic cell counting in whole blood using quantitative PCR-based methylation assays (www.epiontis.com) was done to monitor changes in peripheral FoxP3+ T cells (Tregs), pro-inflammatory Th17 cells, and granulysin+ cells. Results Our data reveal 4 different subgroups of patients associated with distinct signatures of FVIII-specific antibodies. The first subgroup includes 7 subjects who developed FVIII inhibitors by study criteria (B.U. > 0.6 B.U. x 2 measurements from consecutive study days in central laboratory). All 7 subjects had high-risk F8 gene mutations including large deletions (2), intron 22 inversions (4) and duplications (1). Inhibitors in these patients were associated with the development of high-affinity class-switched FVIII-specific antibodies which were detected prior to the first detection of inhibitors. High-affinity IgG1 was generally observed first, followed by high affinity IgG3 and subsequently high-affinity IgG4. Other isotypes and IgG subclasses of anti-FVIII antibodies were only seen occasionally. The second subgroup includes 2 subjects with low titer inhibitors. One subject, who expressed an intron 22 inversion, had a transient low titer FVIII inhibitor (1.4 BU/ml) which was associated with a high-affinity IgG1 antibody only. The other subject, who expressed a frame shift mutation, developed high affinity IgG1 by ED1. This patient had a low titer inhibitor detected (0.8 BU/ml) at ED20 which remained low (0.5 BU/ml) at study end, ED50. No other IgG subclasses were observed in either patient. The third subgroup includes 7 subjects with non-neutralizing antibodies. These subjects expressed intron 22 inversions (3), missense mutations (3) or an intron 1 inversion (1). Six of these patients developed low-affinity IgG1 antibodies which were observed until study end without the appearance of high-affinity antibodies or any other IgG-subclass. No FVIII inhibitors were detected at any time. The remaining subject initially developed low-affinity IgG1 antibodies and subsequently high-affinity IgG1 which remained until study end. No other IgG subclasses and no FVIII inhibitor were detected. The fourth subgroup includes 7 subject who never developed any FVIII-specific antibodies or FVIII inhibitors. These patients expressed missense mutations (3), an intron 22 inversion (1), a duplication (1), a frameshift mutation (1) or a nonsense mutation (1). Relative proportions of circulating FoxP3+ T cells (Tregs), Th17 cells or granulysin+ cells did not correlate with the development of FVIII inhibitors or FVIII-specific antibodies in individual PUPs. Conclusions Data obtained from the HIPS study identify four distinct patient subgroups based on their specific antibody signatures. Most importantly, high affinity class-switched antibodies preceded clinical inhibitor detection, substantiating their potential role as suitable predictive biomarkers for inhibitor development. Disclosures Gangadharan: Shire: Employment. Reipert:Shire: Employment, Equity Ownership. Berg:Research Institute for Applied Bioanalytics and Drug Development, IMC Fachhochschule Krems /: Research Funding. Scheiflinger:Shire: Employment, Equity Ownership. Blatny:Shire, Pfizer, Roche: Consultancy, Speakers Bureau. Fijnvandraat:CSL Behring, Bayer, Shire: Membership on an entity's Board of Directors or advisory committees, Research Funding. Gruppo:Shire: Honoraria, Membership on an entity's Board of Directors or advisory committees. Male:CSL Behring: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Bayer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Biotest: Speakers Bureau; Novo Nordisk: Speakers Bureau; Octapharma: Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Shire: Speakers Bureau; SOBI: Speakers Bureau. McGuinn:Shire: Research Funding; BioMarin: Consultancy; CSL Behring: Consultancy; Pfizer: Research Funding; Spark: Consultancy, Research Funding; Bioverativ: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Consultancy. Meeks:HEMA Biologics: Other: Advisory Board; Genentech: Other: Advisory Board; Catalyst Biosciences: Other: Advisory Board; CSL Behring: Other: Advisory Board; Bayer: Other: Advisory Board; Bioverativ: Other: Advisory Board; Shire: Other: Advisory Board; Pfizer: Research Funding. Ragni:MOGAM: Membership on an entity's Board of Directors or advisory committees; Shire: Research Funding; Sangamo: Research Funding; SPARK: Consultancy, Research Funding; Novo Nordisk: Research Funding; Biomarin: Membership on an entity's Board of Directors or advisory committees, Research Funding; CSL Behring: Research Funding; Alnylam: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bioverativ: Consultancy, Research Funding. Recht:Shire: Research Funding; Biogen: Research Funding; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees, Research Funding; Kedrion: Membership on an entity's Board of Directors or advisory committees. Santagostino:Bayer, Shire, CSL Behring, Pfizer, Novo Nordisk, Grifols, Kedrion, Sobi, Bioverativ, Octapharma, Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Shapiro:Bayer Healthcare: Other: International Network of Pediatric Hemophilia; Octapharma: Research Funding; Prometic Life Sciences: Consultancy, Research Funding; Daiichi Sankyo: Research Funding; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genetech: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Bio Products Laboratory: Consultancy; Shire: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Sangamo Biosciences: Consultancy; Kedrion Biopharma: Consultancy, Research Funding; Bioverativ, a Sanofi Company: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; OPKO: Research Funding; BioMarin: Research Funding. Staber:NovoNordisk: Consultancy; Bayer: Honoraria; uniQure: Honoraria. Brown:Shire: Research Funding.

Background and objectives The Hemophilia Inhibitor PUP Study (HIPS, clinicaltrials.gov NCT01652027) is a prospective multicenter observational study of PUPs with severe hemophilia A during their first 50 exposure days (EDs) to recombinant Factor VIII (FVIII, Advate TM). The objective is to elucidate immune system changes and identify potential early biomarkers of inhibitor development in PUPs. Previously we reported that the appearance of high-affinity anti-FVIII antibodies preceded clinical diagnosis of FVIII inhibitors in patients (Reipert 2016). Here we present longitudinal antibody data including titers of FVIII-specific IgM, IgG1-4, IgA, apparent affinities of antibodies and titers of FVIII inhibitors for the first 15 patients who completed the antibody analysis of the HIPS study. Moreover, we present longitudinal monitoring data for key circulating immune cells such as FoxP3+ T cells (Tregs), pro-inflammatory Th17 cells, total T cells and granulysin+ NK cells. Methods FVIII inhibitor testing (Nijmegen methodology, performed in the central laboratory Medical College of Vienna) and antibody analytics were done prior to first exposure, 7-9 days after ED 1 and 5-7 days after EDs 5, 10, 20, 30, 40, and 50. FVIII-specific antibody analytics, including specifications of isotypes, IgG subclasses and apparent affinities were done using methodology described by Whelan 2013 and Hofbauer 2015. Circulating immune cells including FoxP3+ T cells (Tregs), pro-inflammatory Th17 cells, total T cells and granulysin+ NK cells were monitored by epigenetic cell counting in whole blood using quantitative PCR-based methylation assays (www.epiontis.com) Results 25 subjects have been enrolled among 15 study sites. Data for 15 subjects who had completed 50 exposure days were available for analysis. Among these 15 subjects, 4 developed FVIII inhibitors by study criteria (> 0.6 B.U. x 2 measurements in central laboratory) at exposure days 6, 10 and 20. All inhibitors were associated with the development of high affinity FVIII-specific antibodies. High-affinity IgG1 antibodies were detected first and subsequently switched to IgG3 and IgG4, switching to IgG2 was observed only in one of the 4 patients. Two of the 4 inhibitor patients initially developed low affinity IgG1 antibodies which were subsequently accompanied by high affinity IgG1 before switching to high-affinity IgG3 and IgG4. One of the 4 inhibitor patients expressed non-neutralizing FVIII-specific IgG1 antibodies prior to first FVIII infusion already and developed a high-titer inhibitor as early as ED6 Six of the 15 patients who had completed 50 exposure days developed non-neutralizing antibodies (detected on at least 2 time points). Five of them expressed low affinity IgG1 which was never accompanied by high affinity IgG1 or by any other IgG subclass. One of the 6 patients initially expressed low affinity IgG1 which was later accompanied by non-neutralizing high affinity IgG1. Switching to other IgG subclasses was not observed. Three patients had no antibodies detected and 2 had non-neutralizing antibodies detected at a single time point only. Levels of circulating FoxP3+ Tregs in the infant patients were in the same range as in healthy adults with some variation between individuals. In contrast, circulating TH17 cells were barely detectable. The levels of granulysin+ NK cells showed substantial variations between patients as well as during longitudinal monitoring in the same patient. Conclusion Antibody data obtained from the first 15 patients who completed 50 exposure days in the HIPS study confirms that FVIII inhibitor development is preceded by the detection of high-affinity FVIII-specific antibodies. High affinity IgG1 antibodies appeared first and subsequently switched to IgG3 and IgG4 which indicates a T-cell dependent pathway in FVIII inhibitor development. Switching to IgG2 was only seen in 1 of the 4 inhibitor patients. In contrast, patients with non-neutralizing antibodies only expressed IgG1 antibodies and never switched to another IgG subclass. 5 of the 6 patients with non-neutralizing antibodies only expressed low affinity IgG1 which might reflect a T-cell independent pathway of antibody development. In summary, our data indicate that comprehensive analysis of FVIII-specific antibodies might provide early biomarkers which indicate evolving FVIII inhibitors. Disclosures Gangadharan: Shire: Employment. Reipert: Shire: Employment. Scheiflinger: Shire: Employment. Bowen: Shire: Research Funding. Fijn van Draat: ZonMW,CSL Behring: Research Funding; Baxalta: Membership on an entity's Board of Directors or advisory committees; Pfizer, Novo Nordisk: Other: Lectures. Gruppo: Shire: Other: Honorarium for participation on physician advisory board. Male: Bayer, Baxalta, Biotest, CSL Behring, Novo Nordisk, Pfizer: Other: Speaker Honoraria and/Travel support. McGuinn: Shire/Baxalta: Consultancy; Shire / Baxalta, Spark, Biogen, Roche/Genetehc: Research Funding. Recht: Baxalta, Novo Nordisk, Biogen, Pfizer: Research Funding; Biogen , Kediron: Consultancy. Ragni: A Anylam,Biomarin,Tecere, Benitec: Honoraria; Alnylam, CSL Behring, Dimensions, Genetech/Roche,Pfizer, Shire, SPARK: Research Funding. Yaish: Baxalta, Bayer and Octapharma, CSL behring: Consultancy, Membership on an entity's Board of Directors or advisory committees; Baxalta: Honoraria, Membership on an entity's Board of Directors or advisory committees. Santagostino: : Bayer, Shire, Pfizer, Novo Nordisk, Kedrion, Roche, Sobi, Bioverativ, CSL Behring, Grifols, Octapharma: Speakers Bureau; Bayer, Shire, Pfizer, Novo Nordisk, Kedrion, Roche, Sobi, Bioverativ: Other: Advisory board. Brown: Shire: Research Funding.

Background: Earlier data demonstrated long-term expression of factor IX (mean FIX:C ~5.1%) following AAV8-mediated gene transfer at 2 x1012 vg/kg in hemophilia B (Nathwani et al., 2014). While the clinical improvement imparted by stable FIX levels is clear, these levels of expression fall short of trough values obtained by long-acting FIX prophylaxis (Santagostino et al. 2016), and of natural history data suggesting that levels of ~12% are required to eliminate spontaneous hemarthroses (den Uijl et al. 2011). Achieving higher levels of FIX:C with dose escalation has not been possible without eliciting a dose-dependent, capsid-specific immune response that may prevent sustained expression and efficacy (Mingozzi et al. 2007, Monahan et al. 2015). We sought to develop a highly efficient vector capsid and expression cassette that could be administered at low doses to achieve hemostatic FIX expression without need for immunosuppression. Methods: The investigational product, SPK-9001, utilizes a bioengineered AAV capsid (Spark100) with liver specific tropism. The prevalence of neutralizing antibodies (NAb) to Spark100 among sampled hemophilia B sera was 40% (Anguela et al. 2015). The expression cassette is a codon-optimized, single-stranded transgene encoding FIX Padua, a naturally occurring variant with a single amino acid substitution (R338L) that confers ~8-fold greater specific activity compared to wild-type FIX (Simioni et al. 2009). Data on bleeding and factor infusions in the year prior to enrollment were retrospectively compiled. Laboratory values, bleeding frequency, FIX consumption, changes in activity and quality-of-life via Haem-A-QoL were prospectively evaluated after vector infusion. Results: We enrolled 9 subjects, of whom 2 failed screening for liver fibrosis and 7 were infused with SPK-9001 at a dose of 5 x1011 vg/kg. Infused subjects were adult males ages 18-52 years with baseline FIX:C 2-34 weeks after vector infusion. Figure 1 outlines subject vector-derived FIX:C for the first 12 weeks. There have been no vector or procedure related adverse events. Steady-state FIX expression is reached by 12 weeks after vector infusion, resulting in a mean FIX:C of 32.3% ±6.5%. To date, no subjects required immunosuppression or demonstrated evidence of a cytotoxic immune response (characterized by loss of FIX activity, elevation of transaminase values >/=1.5-times the upper limit of normal, and positive IFN-gammaELISPOT response to capsid peptides). No subjects developed a FIX inhibitor or demonstrated ELISPOT reactivity to the FIX (R338L) gene product. Subject 3 infused with FIX concentrate for a suspected ankle bleed 2 days after vector infusion. Beyond this, no subjects required factor or experienced any bleeding events. The 4 subjects previously maintained on prophylaxis safely stopped without break-through bleeding. As of today (cumulative 724 days post vector infusion), total factor consumption was reduced by 543,589 IU, tantamount to a cumulative savings of $1,182,298 USD.Six of 7 subjects report increased physical activity and improved quality of life. Conclusion: As of 8/4/2016, we report the highest and most consistent levels of sustained vector-derived FIX:C following FIX gene transfer. Levels of FIX:C achieved by SPK-9001 permitted termination of prophylaxis, prevention of bleeding, and nearly complete cessation of factor use. Despite the heterogeneity in subjects with respect to presence and extent of hemophilic arthropathy, age, and co-morbidities, consistency of transgene expression and clinical outcomes have been observed in all participants studied to date. A vector dose of 5x1011 vg/kg is the lowest dose currently reported in hemophilia gene transfer trials; the absence of any observed CD8+ T cell immune response supports the hypothesis that lowering the dose can reduce or eliminate the risk of a capsid-specific immune response and maximize efficacy. In summary, preliminary data suggest SPK-9001 safely and consistently produces sustained elevation in FIX:C levels sufficient to prevent spontaneous hemarthroses without the need for factor consumption or immunosuppression. Disclosures Ducore: Octapharama: Membership on an entity's Board of Directors or advisory committees; LFB: Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Biogen: Membership on an entity's Board of Directors or advisory committees; CSL Behring: Membership on an entity's Board of Directors or advisory committees; Baxalta (Shire): Membership on an entity's Board of Directors or advisory committees; Bayer: Membership on an entity's Board of Directors or advisory committees. Cuker:Biogen-Idec: Consultancy, Research Funding; T2 Biosystems: Research Funding; Genzyme: Consultancy; Stago: Consultancy; Amgen: Consultancy. McGuinn:Spark: Research Funding; Biogen: Research Funding; Novo Nordisk: Research Funding; Baxalta: Research Funding. Luk:Spark Therapeutics, Inc.: Employment. Wright:Spark Therapeutics, Inc.: Employment, Equity Ownership, Patents & Royalties: SPK-9001. Chen:Spark Therapeutics, Inc.: Employment. Hui:Spark Therapeutics, Inc.: Employment. Wachtel:Spark Therapeutics, Inc.: Employment. Urich:Spark Therapeutics, Inc.: Employment. Takefman:Spark Therapeutics, Inc.: Employment. Couto:Spark Therapeutics, Inc.: Employment. Carr:Pfizer, Inc.: Research Funding. Anguela:Spark Therapeutics, Inc.: Employment, Patents & Royalties: SPK-9001. High:Spark Therapeutics, Inc.: Employment, Equity Ownership, Patents & Royalties: SPK-9001.

Background and Objectives The development of neutralizing antibodies (inhibitors) to factor VIII (FVIII) represents the major complication following replacement therapy with FVIII products in patients with hemophilia A. Why some patients develop FVIII inhibitors while others do not is poorly understood. Identification of early biomarkers which predict inhibitor development in previously untreated patients (PUPs) with hemophilia A will assist in risk identification and possible early intervention strategies. Previous analysis of FVIII-specific antibodies in different cohorts of patients with severe hemophilia A and in healthy individuals indicated distinct spectra of neutralizing and non-neutralizing antibodies (Whelan SFJ et al. Blood 2013). FVIII-specific antibodies found in hemophilia A patients with inhibitors have approximately 100-fold higher apparent affinities than that of antibodies found in patients without inhibitors or in healthy individuals (Hofbauer CJ et al. Blood 2015). In one individual, high affinity FVIII-specific antibodies were detectable prior to the diagnosis of FVIII inhibitors. The Hemophilia Inhibitor PUP Study (HIPS) is a prospective multicenter observational study of PUPs with severe hemophilia A during their first 50 exposure days (EDs) to recombinant FVIII (Advate TM). The objective is to elucidate immune system changes and identify potential early biomarkers of inhibitor development in PUPs. This is the first report of FVIII-specific antibody development in the first 10 subjects who have completed the study. Methods HIPS study procedures have been previously described (Hofbauer CJ et al. 2015; clinicaltrials.gov NCT01652027). FVIII inhibitor testing by Nijmegen methodology performed in a central laboratory (Medical College of Vienna) and FVIII-specific antibody analytics were done prior to first exposure, 7-9 days after exposure day (ED) 1 and 5-7 days after EDs 5, 10, 20, 30, 40, and 50. FVIII-specific antibody analytics, including specifications of isotypes, IgG subclasses and apparent affinities were done using methodology described in Whelan 2013 and Hofbauer 2015. Results: Currently, 24 subjects have been enrolled among 19 study sites. Data for 10 subjects were available for analysis. Among these 10 subjects, 2 developed FVIII inhibitors by study criteria (B.U. > 0.6 B.U. x 2 measurements in central laboratory) by exposure days 6 and 20 (see figure 1). A third subject is expected to meet study criteria for FVIII inhibitor due to multiple high titer measurements reported over time at a local laboratory. All three inhibitor patients revealed antibody class switching from IgG1 to IgG4 and affinity maturation resulting in the generation of high affinity FVIII-specific antibodies. High-affinity FVIII-specific IgG1 antibodies were detectable prior to inhibitor diagnosis in all 3 inhibitor subjects. One subject with a transient FVIII inhibitor showed medium affinity FVIII-specific IgG1 antibodies which persisted until ED50, but never developed high-affinity antibodies. Another subject without a detectable inhibitor developed low titer, low affinity IgG1 antibodies that persisted to ED 50 without the development of high-affinity antibodies. The remaining subjects had no inhibitor and no detectable FVIII-specific antibodies. Conclusions: Interim data from HIPS suggests that FVIII inhibitor development is preceded by the detection of high-affinity FVIII-specific antibodies which undergo class switch from IgG1 and IgG3 to IgG4. The findings confirm affinity maturation of FVIII-specific antibodies which require T-cell dependent antibody responses resulting from germinal center reactions. While low affinity IgG1 antibodies were sometimes seen in subjects without inhibitors, high-affinity antibodies were only seen in subjects who developed inhibitors. Our data indicate that high affinity FVIII-specific antibodies preceded the clinical diagnosis of an inhibitor and may serve as early biomarkers of FVIII inhibitor development facilitating early immune intervention. Figure 1. Kinetic of FVIII-binding antibodies and FVIII inhibitors in patient 0902. High-affinity FVIII-specific IgG1 antibodies were first detected after exposure day 6, FVIII inhibitors were first diagnosed after exposure day 20. Figure 1. Kinetic of FVIII-binding antibodies and FVIII inhibitors in patient 0902. High-affinity FVIII-specific IgG1 antibodies were first detected after exposure day 6, FVIII inhibitors were first diagnosed after exposure day 20. Disclosures Reipert: Shire: Employment, Research Funding. Gangadharan:Shire: Employment, Research Funding. Hofbauer:Shire: Employment. Scheiflinger:Shire: Employment, Research Funding. Bowen:Baxalta: Research Funding. Donnachie:Baxalta: Research Funding; CSL Behring: Research Funding; Bayer Healthcare: Research Funding. Fijvandraat:CSL Behring: Research Funding; Bayer Healthcare: Research Funding; Baxalta: Membership on an entity's Board of Directors or advisory committees. Gruppo:Baxalta: Honoraria, Membership on an entity's Board of Directors or advisory committees. Male:Baxalta: Other: travel support; Novo Nordisk: Other: travel support; Biotest: Other: travel support; Bayer Healthcare: Other: travel support; CSL Behring: Other: travel support; Pfizer: Other: travel support. McGuinn:Baxalta: Research Funding; Novo Nordisk: Research Funding; Spark: Research Funding; Biogen: Research Funding. Meeks:Genentech: Membership on an entity's Board of Directors or advisory committees; Bayer Healthcare: Membership on an entity's Board of Directors or advisory committees; Grifols: Membership on an entity's Board of Directors or advisory committees; Biogen: Membership on an entity's Board of Directors or advisory committees; CSL Behring: Membership on an entity's Board of Directors or advisory committees; Shire: Membership on an entity's Board of Directors or advisory committees. Recht:Novo Nordisk: Consultancy, Research Funding; Baxalta: Research Funding; Biogen Idec: Research Funding; Kedrion: Consultancy. Ragni:Biogen: Research Funding. Yaish:Octapharma: Consultancy; Bayer Healthcare: Consultancy; Baxalta: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Santagostino:Sobi: Consultancy; Biogen Idec: Consultancy; Novo Nordisk: Consultancy; Pfizer: Consultancy; Octapharma: Consultancy; Baxalta: Consultancy; Kedrion: Consultancy; CSL Behring: Consultancy; Bayer: Consultancy; Grifols: Consultancy; Roche: Consultancy. Brown:Baxalta/Shire: Research Funding.

Background Cyclophosphamide-based conditioning regimens and allogeneic hematopoietic stem cell transplantation (AlloHSCT) from matched related donors (MRD) has resulted in the highest survival rates in children and adolescents with acquired severe aplastic anemia (SAA). Time to transplant has consistently been associated with decreased overall survival. Reduced toxicity conditioning and AlloHSCT has been used successfully in other pediatric non-malignant diseases. Procedure We piloted a risk-adapted AlloHSCT approach, using fludarabine and anti-thymocyte globulin based conditioning with high (200 mg/kg) and low (60 mg/kg) dose cyclophosphamide as upfront treatment in newly diagnosed pediatric patients with acquired SAA incorporating alternative donor sources, including cord blood. Average risk for non-engraftment patients with

Fetal and neonatal alloimmune thrombocytopenia is characterized by the presence of transient isolated thrombocytopenia secondary to maternal antibodies against paternally inherited antigens expressed on the fetal platelet. Fetal and neonatal alloimmune thrombocytopenia is the most common cause of severe thrombocytopenia ( in utero and perinatal intracranial hemorrhage with resulting long term neurological disability or death. Prompt investigation of thrombocytopenia is critical for management of the neonate and future pregnancies. Significant improvement in fetal/neonatal outcome has occurred with maternal treatment with intravenous immune globulin.

This chapter will focus on the acquired etiologies of neonatal thrombocytopenia. Neonatal thrombocytopenia occurs in 1–2% of healthy term neonates, but is more common in the neonatal intensive care unit (NICU) where thrombocytopenia occurs in up to one third of all admissions. Thrombocytopenia in the fetus and neonate is defined as platelet count

Background: Eltrombopag (Epag) is an oral thrombopoietin receptor agonist used to increase platelet counts in patients with chronic immune thrombocytopenia (cITP). The maximum licensed Epag dose in cITP patients is 75 mg daily, yet some patients do not respond at this dose. Healthy individuals on escalated doses of eltrombopag (100-200 mg) demonstrated a dose dependent platelet response as did patients with thrombocytopenia secondary to chemotherapy. Doses of 100 mg and 150 mg have been approved for use in patients with hepatitis-C induced thrombocytopenia and aplastic anemia respectively. This is the final report of a double-blind, randomized controlled study to determine if Epag, administered at doses up to 150 mg daily, increases platelet counts in cITP patients who failed to respond to 75 mg. Methods: cITP patients³ 1 year old with platelet counts 3 weeks of 75mg of Epag daily), stratified by splenectomy status, were enrolled. Patients could continue stable doses of concomitant ITP medications. In the randomized blinded phase (Part 1), patients first received 75 mg daily of active Epag and 25 mg of study drug (Epag or placebo, 2:1). Every two weeks, study drug doses were increased in 25 mg increments to a maximum daily dose of 150 mg. After 8 weeks subjects were unblinded. If on active drug, they entered the open label phase (Part 2); if on placebo, they received open label Epag as per the study protocol escalating to a maximum dose of 150 mg. Two patients entered part 2 before 8 weeks because their counts were >100,000/uL in the blinded phase. Data analysis was descriptive. Mann Whitney U test estimated p-values (α Results: As of July 31, 35 patients consented; 26 completed ³8 weeks on study medication. Two patients are in part 1 and 7 dis-enrolled before completing 8 weeks of study drug: 5 failed screening and never received medication; one had bleeding and low counts on placebo; and one had pre-existing reticulin fibrosis 2-3+, discovered after study drug was dispensed but not administered. The most common adverse event (AE) was minor bleeding. Two adults and 2 children developed transaminitis, which was life-threatening in 1 adult on 100mg. The 4 liver AEs occurred between 2 and 20 weeks of Epag dosing with 3/4 subjects on 150 mg daily; 2/4 discontinued Epag. No strokes or thromboembolic events were seen nor did any cataracts develop. Three patients underwent bone marrows: no grade 2-3 fibrosis was seen. Platelet counts for patients on active drug vs placebo separated by week 2 (Figure 1A) and the difference steadily increased until week 8 (p Twenty-six patients entered the long-term open-label study. Three discontinued prior to 24 weeks because of transaminase elevation (1) and no response (2); 7 are not yet at 24 weeks; and 6 were also on other treatments, ie IVIG at increased intervals while on Epag, obscuring their responses. Ten patients were on open label medication for >24 weeks past the 8 weeks in part 1 up to 110 weeks. 72% of the long-term counts in these 10 patients were > 50,000/uL while 40% were > 100,000/uL. Six patients took 150 mg daily for >24 weeks while 4 reduced their doses, though not to Conclusions: The results demonstrate that Eltrombopag at doses of 100-150mg daily can elevate platelet levels in most children and adults with cITP whose platelet counts were 3 weeks. Children responded better to increased doses of Epag than did adults and high dose Epag can be used long term without development of cataracts, strokes or other thromboembolic events although an increased frequency of liver events, 12%, occurred. Although the 150 mg dose can be safely continued for many months, monitoring transaminases is essential. Disclosures Off Label Use: Increased doses of eltrombopag. McGuinn:Baxter: Research Funding; Octapharma: Membership on an entity's Board of Directors or advisory committees. Bussel:Momenta: Membership on an entity's Board of Directors or advisory committees; Genzyme: Research Funding; BiologicTx: Research Funding; Symphogen: Membership on an entity's Board of Directors or advisory committees; Cangene: Research Funding; Amgen: 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; Protalex: Membership on an entity's Board of Directors or advisory committees; 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; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Sysmex: Research Funding; Immunomedics: Research Funding; Shionogi: Membership on an entity's Board of Directors or advisory committees, Research Funding.

PCDH10has been implicated as a tumor suppressor, since epigenetic alterations of this gene have been noted in multiple tumor types. However, to date, studies regarding its role in acute and chronic leukemias are lacking. Here, we have investigated the presence of promoter hypermethylation of two CpG islands of thePCDH10gene by methylation-specific PCR in 215 cases of various subsets of myeloid- and lymphoid-lineage leukemias. We found thatPCDH10promoter hypermethylation was frequent in both B-cell (81.9%) and T-cell (80%) acute lymphoblastic leukemia (ALL), while it was present in low frequency in most subtypes of myeloid leukemias (25.9%) and rare in chronic myeloid leukemia (2.2%).PCDH10expression was downregulated via promoter hypermethylation in primary ALL samples (N!4) and leukemia cell lines (N!11). The transcriptional repression caused byPCDH10methylation could be restored by pharmacologic inhibition of DNA methyltransferases. ALL cell lines harboring methylation-mediated inactivation ofPCDH10were less sensitive to commonly used leukemia-specific drugs suggesting thatPCDH10methylation might serve as a biomarker of chemotherapy response. Our results demonstrate thatPCDH10is a target of epigenetic silencing in ALL, a phenomenon that may impact lymphoid-lineage leukemogenesis, serve as an indicator of drug resistance and may also have potential implications for targeted epigenetic therapy. V C 2011 Wiley Periodicals, Inc.

Introduction The thrombopoietin (TPO) mimetic agents romiplostim and eltrombopag are used to stimulate platelet production and increase platelet counts in chronic immune thrombocytopenia (ITP) in adults. While two large, randomized trials investigating dosing, safety, and efficacy were ongoing in children, but not near completion, we conducted a retrospective IRB-approved analysis of 33 pediatric (≤21 years) chronic ITP patients from two centers treated with TPO agents off-study. Patients Patients initiated TPO therapy prior to 21 years of age (19 months to 19 years, median 14 years) after an average of 3.6 ITP therapies; 21 patients received romiplostim [11 at Children's Hospital of Orange County (CHOC), 10 at Weill Cornell Medical Center (WCMC)] and 12 eltrombopag [all at WCMC]. Median starting age was 11.5 years for patients on romiplostim and 16.5 years on eltrombopag. Primary response measures were: platelet counts ≥ 50 x 109 per liter or ≥20 x 109 per liter above baseline for 2 consecutive weeks and 50% of platelet counts ≥ 50 x 109 per liter. Duration of treatment and bone marrows with myelofibrosis (MF) consensus grade are shown in Figure 1. Results 27/33 (82%) patients responded to TPO agents; 18/21 to romiplostim and 9/12 to eltrombopag. Ten patients responded to ROMIPLOSTIM as a single agent; 8 romiplostim responders received concurrent medications including: mycophenolate mofetil (MMF), azathioprine (AZA), rituximab, and cyclosporine (CSA). One of two splenectomized patients was able to wean off TPO therapy with adequate counts. Two additional patients successfully discontinued TPO therapy and continued on MMF alone. Two patients (1 CSA, 1 AZA) successfully discontinued TPO therapy and then weaned off concurrent therapy. Eighteen of 21 patients had platelet counts ≥ 50 x 109 per liter or ≥20 x 109 per liter above baseline for 2 consecutive weeks and 18 had 50% of platelet counts ≥ 50 x 109 per liter (table). In this study, duration of successful romiplostim use outside of randomized clinical trials ranged from 6-44 months (11/18 ongoing). 3 patients did not respond and 2/3 went on to have therapeutic splenectomies. 1 patient with Evans syndrome had a transient 1 year response before relapsing. 5 responders to romiplostim had previously received eltrombopag with lesser or no effect. Nine of 12 patients responded to ELTROMBOPAG with platelet counts ≥ 50 x 109 per liter or ≥20 x 109 per liter above baseline for 2 consecutive weeks and 8/12 had 50% of platelet counts ≥ 50 x 109 per liter. One patient had been splenectomized; 7 responded to eltrombopag alone. 2 patients had concurrent therapy with prednisone and IV Anti-D and 1/2 was able to discontinue concurrent prednisone. One patient successfully discontinued eltrombopag with adequate counts for > 1 year. 5 patients attempted unsuccessfully to discontinue therapy. One responder, a previous romiplostim responder, switched to eltrombopag. No other patients were treated with TPO agents prior to starting eltrombopag. Duration of successful eltrombopag use outside of randomized clinical trials ranged from 23-53 months (7/12 are ongoing). Three patients did not respond to eltrombopag; 1/3 was HIV positive. One patient experienced a provoked DVT at site of ankle fracture while using eltrombopag. No other patients on either therapy experienced serious drug-related adverse events. Among 24 bone marrows (both agents; 21 reflecting off study use), only MF grades 0 -1 were seen. 10/24 marrows were performed after greater than 2 years of therapy. Conclusion Retrospective analysis of off-study use of eltrombopag and romiplostim in children shows that these TPO agents effectively increase platelet counts in more than 3/4 of children with chronic ITP, a result consistent with adult TPO use. Despite small sample size, the long-term duration of successful use (6-53 months) without tachyphylaxis supports efficacy. Re safety, the one DVT appeared to be precipitated by a fracture and there were no MF2/3 bone marrows in the 24 samples. In those patients who do not respond to one TPO agent, it may be beneficial to switch to the other form. Disclosures: Nugent: Bayer: Honoraria; CSL Behring: Honoraria; Novo Nordisk: Honoraria. Bussel: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; Cangene: Research Funding; GlaxoSmithKline: Equity Ownership, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Amgen: Equity Ownership, 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.

Background Eltrombopag is an oral thrombopoietin receptor agonist which increases platelet counts in immune thrombocytopenia (ITP) patients by increasing proliferation of megakaryocyte (Mk) precursors and Mk. Maximal approved eltrombopag dosage in chronic ITP patients is 75mg daily, yet some patients do not respond at this dose. In a prior 6-week study, a numerically higher proportion of patients responded at 75mg vs. 50mg. Data of the pharmacokinetics, safety and tolerability of eltrombopag in healthy volunteers at an escalated dosage (100-200mg) showed a dose dependent platelet response. Doses > 75mg have been used in other settings without additional toxicity, including Aplastic Anemia and Chronic Hepatitis C associated thrombocytopenia. Taken in conjunction, a higher eltrombopag dose may be effective in treating ITP in non-responders without increased toxicity. The following double blind, randomized controlled study is in progress to determine if eltrombopag administered at up to 150mg daily increases platelet counts and lessens bleeding symptoms in ITP patients who failed to respond to 75 mg. Methods Non-responders (patients ≥ 12 years old with platelet counts50,000 μL AND an overall increase from baseline >20,000 μL not attributable to rescue therapy in the 8 weeks from initiating dose escalation. Subjects are considered partial responders (PR) if they have 2 consecutive platelet counts of >50,000 μL OR an overall increase from baseline >20,000 μL not attributable to rescue therapy by 8 weeks (figure). Monitoring includes baseline cataract exams with additional eye exams at 6 and 18 months, bleeding evaluations every 2 weeks (Part 1) and bone marrow biopsy after 1 year (Part 2). Results 13 patients (2 adolescents and 11 adults) have been enrolled in the study. Of the 5 adult patients who completed ≥ 8 weeks on active medication, 3 achieved either CR (1) or PR (2). The 2 PRs had an increase from baseline to highest count ranging from 23-47,000 μL. 2/3 responders achieved higher platelet counts in the open label extension phase suggesting a longer term slow onset effect of eltrombopag. One PR decreased her daily prednisone dose from 30 mg to 10 mg, with platelet count fluctuations attributed to dietary guideline non-adherence. As of August 8, 6 patients are in Part 1, 4 patients are in Part 2, and 3 have been removed from the study (one patient had elevated transaminases in Part 2, week 12; one patient had pre-existing reticulin fibrosis 2-3+ without clinical symptoms. This pre-study bone marrow result was not available at randomization, but the patient was withdrawn prior to any study drug administration. She had previously received treatment with two other TPO agents; the third patient withdrew secondary to increased bleeding symptoms while on the placebo arm). Other adverse events related to eltrombopag have been mild or moderate. Rescue therapies include intravenous immunoglobulin (IVIG) and prednisone. Most patients have had pre-treatment or recent bone marrows biopsies with a follow up biopsy planned after one year of treatment at 150mg. Conclusions To date, the results demonstrate moderate responses to eltrombopag at increased doses to 150mg daily in the 3 responding patients who have been treated the longest. One subject achieved a CR and two a PR. Three subjects were removed for toxicity but in one it was for marrow findings that antedated study enrollment and another for bleeding while receiving placebo therapy. Interim analysis will be performed after 20 enrolled patients and younger patients might enter the study following completion of ongoing eltrombopag studies in pediatric patients with chronic ITP. Disclosures: Bussel: 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; Sysmex: Research Funding; Eisai: Membership on an entity’s Board of Directors or advisory committees, Research Funding; Immunomedics: Research Funding; IgG of America: Research Funding; Genzyme: Research Funding; Cangene: Research Funding; GlaxoSmithKline: Equity Ownership, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Amgen: Equity Ownership, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Symphogen: Membership on an entity’s Board of Directors or advisory committees.

The Umbilical Cord Blood Collection Program (UCBCP), administered by UC Davis Health System, is a new statewide public program designed to capture the genetic diversity of Californians through collection of cord blood units (CBUs) for unrelated transplantation. This program is funded with revenue from California state birth certificate fees. The vision for the implementation of the mission by UCBCP is to expand access to cord blood stem cells by targeting current inventory deficiencies to provide greater probabilities that people of any race or ethnicity will find an appropriately matched CBU in the National Cord Blood Inventory (NCBI). In support of these goals, the UCBCP plans to promote targeted education programs for health professionals and to utilize best practices for cord blood collections. Through this process UCBCP will facilitate the provision of high quality CBUs for transplantation, as well as promote research and development of effective treatments utilizing cord blood stem cells by making the CBUs collected that do not meet the criteria for banking available to researchers. Much progress has been made toward developing a sustainable cord blood collection program for the state over the first year. The UCBCP leadership team has been developed andwe have identified cord blood banks through an RFP bidding process that will be partnered with hospitals in various parts of the state. The UCBCP is in varying stages of contract negotiations with three of the public banks who responded to the RFP. To date negotiations are in place for California collections in Southern California to occur at five Scripps hospitals, funded in part by the UCBCP; and by collections set to begin at 13 Kaiser Hospitals, also with support from the UCBCP. In the Central Valley, a collection site is being developed in Fresno, at the Community Regional Medical Center. In the Bay area the UCBCP is in negotiations with several hospitals, including California Pacific Medical Center and Alta Bates. In the Sacramento area, the UCBCP has commitments from 2 hospitals and are seeking the same from two additional birthing centers. At UCDHS, we have received IRB approval for the program, and have now initiated cord blood collections for purposes of collector training and process validation.

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.