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Introduction Haemophilia patients with inhibitors often require a bypassing agent (BPA) for bleeding episode management. Eptacog beta (EB) is a new FDA-approved recombinant activated human factor VII BPA for the treatment and control of bleeding in haemophilia A or B patients with inhibitors (≥12 years of age). We describe here the EB safety profile from the three prospective Phase 3 clinical trials performed to date. Aim To assess EB safety, immunogenicity and thrombotic potential in children and adults who received EB for treatment of bleeding and perioperative care. Methods Using a randomized crossover design, 27 subjects in PERSEPT 1 (12-54 years) and 25 subjects in PERSEPT 2 (1-11 years) treated bleeding episodes with 75 or 225 μg/kg EB initially followed by 75 μg/kg dosing at predefined intervals as determined by clinical response. Twelve PERSEPT 3 subjects (2-56 years) received an initial preoperative infusion of 75 μg/kg (minor procedures) or 200 μg/kg EB (major surgeries) with subsequent 75 μg/kg doses administered intraoperatively and post-operatively as indicated. Descriptive statistics were used for data analyses. Results Sixty subjects who received 3388 EB doses in three trials were evaluated. EB was well tolerated, with no allergic, hypersensitivity, anaphylactic or thrombotic events reported and no neutralizing anti-EB antibodies detected. A death occurred during PERSEPT 3 and was determined to be unlikely related to EB treatment by the data monitoring committee. Conclusion Results from all three Phase 3 trials establish an excellent safety profile of EB in haemophilia A or B patients with inhibitors for treatment of bleeding and perioperative use.

Introduction Surgical procedures in persons with haemophilia A or B with inhibitors (PwHABI) require the use of bypassing agents (BPA) and carry a high risk of complications. Historically, only two BPAs have been available; these are reported to have variable responses. Aim To prospectively evaluate the efficacy and safety of a new bypassing agent, human recombinant factor VIIa (eptacog beta) in elective surgical procedures in PwHABI in a phase 3 clinical trial, PERSEPT 3. Methods Subjects were administered 200 µg/kg (major procedures) or 75 µg/kg eptacog beta (minor procedures) immediately prior to the initial surgical incision; subsequent 75 µg/kg doses were administered to achieve postoperative haemostasis and wound healing. Efficacy was assessed on a 4-point haemostatic scale during the intra- and postoperative periods. Anti-drug antibodies, thrombotic events and changes in clinical/laboratory parameters were monitored throughout the perioperative period. Results Twelve subjects underwent six major and six minor procedures. The primary efficacy endpoint success proportion was 100% (95% CI: 47.8%-100%) for minor procedures and 66.7% (95% CI: 22.3%-95.7%) for major procedures; 81.8% (95% CI: 48.2%-97.7%) of the procedures were considered successful using eptacog beta. There was one death due to bleeding from a nonsurgical site; this was assessed as unlikely related to eptacog beta. No thrombotic events or anti-eptacog beta antibodies were reported. Conclusion Two eptacog beta dosing regimens in PwHABI undergoing major and minor surgical procedures were well-tolerated, and the majority of procedures were successful based on surgeon/investigator assessments. Eptacog beta offers clinicians a new potential therapeutic option for procedures in PwHABI.

Background Hemophilia is characterized by a compromised hemostatic response with delayed development of a clot and the formation of clots that are vulnerable to fibrinolysis. We proposed to study, in vitro and in factor VIII knockout mice (FVIII-KO), whether hemostasis is improved with the addition of tranexamic acid (TXA) to low FVIII plasma concentrations. Methods In vitro, blood samples from adults with severe hemophilia-A, spiked to final concentrations of 0-3-10 and 30IU.dL-1 of FVIII, were studied with and without TXA 0.1 mg/mL using thromboelastography in the presence of tPA (ROTEM-tPA), thrombin generation (TG) assay, and scanning electron microscopy. FVIII-KO mice received prophylaxis before trauma, to obtain circulating plasma FVIII at 3 IU.dL-1 or FVIII 3IU.dL-1 + TXA 0.1 mg/mL. After trauma-induced knee joint bleeding, magnetic resonance imaging, histological analysis, and tail clip assay were used to compare hemostastic efficacy of the two prophylactic strategies. Results A dose-dependent improvement of TG was observed with recombinant FVIII (rFVIII) alone (P = .024). As expected, no effect of TXA on TG capacity was observed. Fibrin fiber diameters were significantly decreased with TXA + rFVIII compared to rFVIII, suggesting a stronger fibrin network. Surprisingly, ROTEM-tPA was normalized with TXA alone. In FVIII-KO mice, blood loss after tail clip was lower after prophylaxis with rFVIII + TXA compared to rFVIII, with no statistical significance (P = .15). However, MRI results and histological analysis of knee joints showed that the addition of TXA significantly decreased joint bleeding (P = .022). Conclusion Our results suggest a potential benefit of TXA when used in combination with FVIII in prophylactic settings.

Introduction Eptacog beta [Sevenfact®, coagulation factor VIIa (recombinant)-jncw] (HEMA Biologics and LFB) is a human rFVIIa variant indicated for the treatment and control of bleeding events (BEs) in adults and adolescents with hemophilia A or B with inhibitors. Eptacog beta has not yet been approved for perioperative management; therefore, a phase 3 trial (PERSEPT 3, NCT02548143) was initiated to evaluate the safety and efficacy of eptacog beta for the prevention of excessive bleeding and achievement of hemostasis in persons with hemophilia A or B with inhibitors (PwHABI) undergoing elective surgery or other invasive procedures. Aims To determine the perioperative safety and efficacy of eptacog beta in major and minor elective procedures in PwHABI. Methods PERSEPT 3 was a global, multicenter, single-arm, phase 3 trial that enrolled male PwHABI who required elective minor or major procedures. IRB approval was obtained, and all subjects provided informed consent. Immediately prior to the start of the procedure, subjects undergoing minor invasive procedures were administered an initial dose of 75 µg/kg eptacog beta and those undergoing major invasive procedures were administered an initial dose of 200 µg/kg eptacog beta. Additional eptacog beta (75 µg/kg) was administered during the procedure and post-operatively (Table 1). Hemostatic efficacy was assessed using a 4-point evaluation scale during the procedure, immediately following the procedure, at regular post-operative intervals, and 48 hours following the last dose of eptacog beta (hemostatic evaluations were recorded as excellent, good, moderate and poor). The primary efficacy endpoint was the percentage of good and excellent responses (ie, successes) at 48 (±4) h following the final dose of eptacog beta and was based upon the investigators' integrated assessment; taking into consideration the investigators' intraoperative hemostatic assessment; the number of postoperative bleeding events and interventions, and blood transfusions; and the amount of eptacog beta used. Results Twelve male subjects (age 2-56 years; median 20 years) were enrolled at 8 sites in 5 countries; all subjects had severe hemophilia A with inhibitors. Six minor procedures [circumcision (3) and tooth extraction (3)] and 6 major procedures (left transtibial amputation, hip replacement, orthopedic knee surgery, amputation of the left leg, left knee joint endoprosthesis removal, and left ankle achilloplasty) were evaluated. The primary efficacy endpoint is shown in Table 2: the success proportion was 67% for major procedures and 100% for minor procedures. The intraoperative efficacy of eptacog beta was rated as good or excellent in all 12 procedures (100% success); mean estimated actual intraoperative blood loss was lower than the mean maximum predicted blood loss for a patient without a bleeding disorder undergoing the same procedure. Efficacy 24 hours following procedure completion was rated as good or excellent in all procedures where data were reported (major, 4/4; minor, 6/6). One subject (major procedure) was withdrawn from the study due to an adverse event (postprocedural hematoma); this subject subsequently received aPCC and NSAIDs and experienced blood loss anemia and GI hemorrhage. One subject (minor procedure) withdrew consent. Other nontreatment-related adverse events included postoperative anemia, post-procedural hemorrhage, procedural pain, wound secretion and hemorrhage. No allergic, hypersensitivity, or anaphylactic events were reported; no anti-eptacog beta antibodies were observed; and no thromboembolic events occurred. Conclusions This controlled study demonstrated the efficacy and safety of 2 different dose regimens of eptacog beta in minor and major elective procedures. The intraoperative hemostatic efficacy of eptacog beta was rated as good or excellent in all major and minor procedures, and the success proportion 48h following the final dose (primary efficacy endpoint) was 82% overall. The breadth of procedures examined (ranging from circumcision and tooth extraction to amputation and hip replacement), low mean blood loss, and high intraoperative efficacy suggests that eptacog beta may be successfully utilized in a variety of minor and major procedures. This study provides useful perioperative data for providers who manage congenital hemophilia A or B patients with inhibitors. Disclosures Escobar: National Hemophilia Foundation: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sanofi: Consultancy, Membership on an entity's Board of Directors or advisory committees; Genentech, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novo Nordisk: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees. Quon:Genentech, Inc./F. Hoffmann-La Roche Ltd: Honoraria, Speakers Bureau; Novo Nordisk: Honoraria, Speakers Bureau; Shire/Takeda: Speakers Bureau; Octapharma: Honoraria; Bayer: Honoraria; Biomarin: Honoraria, Speakers Bureau; Orthopaedic Institute for Children: Current Employment; Bioverativ/Sanofi: Honoraria, Speakers Bureau. Leissinger:Bayer: Consultancy; CSL Behring: Membership on an entity's Board of Directors or advisory committees; Genentech: Consultancy; HEMA Biologics: Consultancy; Takeda: Consultancy; Uniqure: Consultancy; Kedrion: Consultancy; Spark: Consultancy. Luck:Orthopaedic Institute for Children: Research Funding; National Hemophilia Foundaton: Honoraria, Speakers Bureau; Board of Trustees, Orthopaedic Institute for Children: Membership on an entity's Board of Directors or advisory committees. Al-Sabbagh:LFB: Current Employment. Bonzo:LFB USA, Inc.: Current Employment; American Statistical Association: Other; International Statistics Institute: Other; International Association for Statistical Computing: Other. Mitchell:HEMA Biologics: Consultancy. Alexander:HEMA Biologics, LLC: Current Employment, Patents & Royalties: No royalties or benefits. Hermans:Bayer: Consultancy, Research Funding, Speakers Bureau; Pfizer: Consultancy, Research Funding, Speakers Bureau; Shire, a Takeda company: Consultancy, Research Funding, Speakers Bureau; Sobi: Consultancy, Research Funding, Speakers Bureau; Biogen: Consultancy, Speakers Bureau; CAF-DCF: Consultancy, Speakers Bureau; CSL Behring: Consultancy, Speakers Bureau; LFB: Consultancy, Speakers Bureau; Novo Nordisk: Consultancy, Speakers Bureau; Roche: Consultancy, Speakers Bureau; Octapharma: Consultancy, Speakers Bureau; Kedrion: Speakers Bureau; EAHAD: Other; WFH: Other. OffLabel Disclosure: SEVENFACT(R) [eptacog beta, coagulation factor VIIa (recombinant)-jncw] is a human rFVIIa variant indicated for the treatment and control of bleeding events (BEs) in adults and adolescents with hemophilia A or B with inhibitors. Eptacog beta is not yet indicated for perioperative management

Inhibitors of factor VIII (FVIII) remain the most challenging complication of FVIII protein replacement therapy in hemophilia A (HA). Understanding the mechanisms that guide FVIII-specific B cell development could help identify therapeutic targets. The B cell-activating factor (BAFF) cytokine family is a key regulator of B cell differentiation in normal homeostasis and immune disorders. Thus, we used patient samples and mouse models to investigate the potential role of BAFF in modulating FVIII inhibitors. BAFF levels were elevated in pediatric and adult HA inhibitor patients and decreased to levels similar to those of noninhibitor controls after successful immune tolerance induction (ITI). Moreover, elevations in BAFF levels were seen in patients who failed to achieve FVIII tolerance with anti-CD20 antibody-mediated B cell depletion. In naive HA mice, prophylactic anti-BAFF antibody therapy prior to FVIII immunization prevented inhibitor formation and this tolerance was maintained despite FVIII exposure after immune reconstitution. In preimmunized HA mice, combination therapy with anti-CD20 and anti-BAFF antibodies dramatically reduced FVIII inhibitors via inhibition of FVIII-specific plasma cells. Our data suggest that BAFF may regulate the generation and maintenance of FVIII inhibitors and/or anti-FVIII B cells. Finally, anti-CD20/anti-BAFF combination therapy may be clinically useful for ITI.

We conducted a prospective serial laboratory cohort study to assess the correlation of factor VIII (FVIII) levels in response to thrombolysis in patients with large vessel occlusion (LVO) and acute ischemic stroke (AIS). Patients with AIS with anterior circulation LVO were eligible for enrollment if treated within 4.5 hours from last seen normal with intravenous tissue plasminogen activator (tPA). Patients (n = 29) had a mean age of 71 years and median National Institute of Health Stroke Scale of 14. Baseline pre-tPA FVIII was not significantly correlated with clot burden score (−0.147, P = .447) or vessel recanalization (−0.133, P = .499). Median FVIII decreased significantly from baseline to 6 hours post-tPA (282% to 161%, P = .002), but delta in FVIII level did not correlate with vessel recanalization (0.013, P = .948). There was no difference between median FVIII level at baseline and 90 days post-AIS. FVIII level decreased significantly after tPA, but baseline FVIII level and early change in FVIII level were not significant predictors of clot burden, vessel recanalization after thrombolysis, or symptomatic hemorrhage.

Background and Rationale Switching from standard-half-life (SHL) to extended-half-life (EHL) recombinant factor VIII (rFVIII) products allows patients to maintain hemostasis with less frequent dosing and improves the treatment burden for people with hemophilia A (PWHA), leading to an overall improvement in quality of life. Currently, the most common approach is to rely on assumptions informed by patient characteristics and clinical history with or without PK analysis. This 'trial and error' approach can lead to suboptimal protection and can cause harmful bleeds, or an excessive use of rFVIII products leading to an economic impact without easing treatment burden. Currently, there is no defined consensus for determining the most therapeutically and economically appropriate prophylaxis (PPX) regimen for PWHA switching from a SHL to EHL product. While the literature contains documented phenotypic and biologic variables with a high predictive potential for determining the optimal regimen for PWHA who may wish to switch to an EHL product, these criteria have not yet been studied prospectively, neither individually nor in combination. The PREDICT study aims to assess a new scoring system based on the best known phenotypic and biologic variables to select the optimal (individualized and most appropriate) regimen, for a favorable outcome when switching from a SHL rFVIII product to the EHL rFVIII product damoctocog alfa pegol. Study Design and Methods PREDICT is a multi-center, prospective, open-label, phase 4 clinical study in the US. It aims to enroll 65-70 previously treated patients including women (≥150 exposure days), aged ≥12 years old with congenital hemophilia A, regardless of disease severity, who have received prior PPX treatment with a SHL rFVIII product for ≥1 year prior to study participation, with no history or current evidence of inhibitors (≥0.6 BU/ml). Key exclusion criteria include patients with any other inherited or acquired bleeding disorder, a platelet count Each patient will receive a score at baseline, which is expected to aid in selecting the most appropriate damoctocog alfa pegol regimen for the individual. The scoring system consists of five, individually weighted phenotypic and biologic variables. In the first 4 weeks of the study, all patients will start treatment with twice weekly (2×W) damoctocog alfa pegol PPX (Figure 1), as per the US product information. Patients with a high-risk total score, will continue with 2×W PPX for the remainder of the study, while patients with a medium risk score will switch to every 5 days (E5D) PPX after the first 4 weeks for the remainder of the study. Patients with a low-risk score will switch to E5D PPX for a further 4 weeks, then switch to a less frequent dosing (e.g., every 7 days). The primary endpoint is the occurrence of favorable outcomes on the score-selected dosing regimen, analyzed by the proportion of patients with a favorable outcome. A favorable outcome is defined as no change of the risk-score-assigned dosing regimen during the study with one of the following: (1) an improved ABR vs prestudy ABR with either decreased or similar frequency of administration versus prestudy frequency, (2) a decreased dosing frequency and similar ABR versus prestudy. Secondary endpoints include the occurrence of patients with 0 and ≤1 spontaneous bleeds, change from baseline in ABRs, change from baseline in frequency of damoctocog alfa pegol administration and patient-reported outcomes. Descriptive statistical analyses will be performed. An interim analysis may be performed for publication purposes. The patient score is expected to predict the most appropriate damoctocog alfa pegol regimen leading to a favorable outcome for at least 70% of the patients enrolled in the study. A post-hoc analysis of the PROTECT VIII study data was done to evaluate the potential of the scoring system. Considering that not all variables were available in the PROTECT VIII study, it was determined that it was feasible to proceed with the study. The proposed patient scoring system is expected to be an effective tool for determining the optimal PPX regimen for PWHA switching from SHL rFVIII products to damoctocog alfa pegol and could potentially improve quality of life. Figure 1 Figure 1. Disclosures Young: Apcintex, BioMarin, Genentech/Roche, Grifols, Novo Nordisk, Pfizer, Rani, Sanofi Genzyme, Spark, Takeda, and UniQure: Consultancy; Genentech/Roche, Grifols, and Takeda: Research Funding. Reding: Bayer, Biomarin (institutional research funding): Research Funding; Bayer, CSL Behring, NovoNordisk, Sanofi Genzyme, Takeda: Honoraria; Bayer, CSL Behring, NovoNordisk, Sanofi Genzyme, Takeda (advisory committees): Membership on an entity's Board of Directors or advisory committees; Bayer, CSL Behring, Sanofi Genzyme, Takeda: Speakers Bureau. Sidonio: Sanofi, Takeda, Octapharma, Bayer, Biomain, Grifols, Kedrion, Genentech. Catalyst, Guardian Therapeutics, Novo Nordisk, Hema Biologics, Uniqure.: Consultancy, Honoraria. Quon: Orthopaedic Institute for Children: Current Employment. Staber: Bayer, CSL Behring, Sanofi, Takeda: Membership on an entity's Board of Directors or advisory committees. Leissinger: Tulane University: Current Employment; BioMarin: Research Funding; Advisory boards: Bayer, Catalyst, CSL Behring, Dova, Enova, Forma, GBT, Genentech, Sanofi, Takeda, UniQure: Honoraria, Membership on an entity's Board of Directors or advisory committees. Charlet: Bayer: Current Employment. Boukerrou: Bayer: Current Employment.

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 use of activated factor VII (FVIIa) for the treatment of bleeding events in haemophilia patients with inhibitors was first reported over 30 years ago. Since then clinical trials, registries, case series, real‐world experience and an understanding of its mechanism of action have transformed what was originally a scientific curiosity into one of the major treatments for inhibitor patients, with innovative therapeutic regimens, dose optimization and individualized care now widely practiced. Given current understanding and use, it might be easy to forget the years of clinical research that led up to this point; in this review, we lay out changes based on broad eras of rFVIIa use. These eras cover the original uncertainty associated with dosing, efficacy and safety; the transformation of care ushered in with its widespread use; and the optimization and individualization of patient care and the importance of specialized support provided by haemophilia treatment centres. Today with the introduction of novel prophylactic agents such as emicizumab, we once again find ourselves dealing with the uncertainties of how best to utilize rFVIIa and newer investigational variants such as marzeptacog alfa and eptacog beta; we hope that the experiences of the past three decades will serve as a guide for this new era of care.

Inhibitors of factor VIII may rarely occur. The resulting hemorrhagic disorder is called acquired hemophilia A. Presentation, epidemiology, laboratory evaluation, and treatment are discussed. The approach to therapy is two-fold; first is to address any current hemorrhagic challenge, and second is to eradicate the presence of the inhibitor. Acquired von Willebrand syndrome may result from any of over 20 causes, each presenting their unique therapeutic approach. Inhibitors have been discovered and described in all the coagulation factors yet are extremely rare.

The slotted plate device by Zhu et al.1,2 was redesigned to allow for the measurement of very low yield stress values that occur with complex biofluids. The newly built apparatus improves the force measurement with a balance of fine resolution and smooths the vertical motion via a lab jack. The slotted plate geometry was optimized to further reduce wall slip as well as pressure drag via computational fluid dynamics (CFD). To improve on the yield stress measurement accuracy, the new design has a large slot area ratio and a large number of slots, as well as sharp front and rear edges. Test results for a few structured fluids, including blood, are compared with yield stress values determined via a TA Instruments AR-2000 rheometer.

Background and Purpose Elevated levels of coagulation factor VIII (FVIII) may persist independent of the acute-phase response; however, this relationship has not been investigated relative to acute ischemic stroke (AIS). We examined the frequency and predictors of persistently elevated FVIII in AIS patients. Methods AIS patients admitted between July 2008 and May 2014 with elevated baseline FVIII levels and repeat FVIII levels drawn for more than 7 days postdischarge were included. The patients were dichotomized by repeat FVIII level for univariate analysis at 150% and 200% activity thresholds. An adjusted model was developed to predict the likelihood of persistently elevated FVIII levels. Results Among 1616 AIS cases, 98 patients with elevated baseline FVIII had repeat FVIII levels. Persistent FVIII elevation was found in more than 75% of patients. At the 150% threshold, the prediction score ranged from 0 to 7 and included black race, female sex, prior stroke, hyperlipidemia, smoking, baseline FVIII > 200%, and baseline von Willebrand factor (vWF) level greater than 200%. At the 200% threshold, the prediction score ranged from 0-5 and included female sex, prior stroke, diabetes mellitus, baseline FVIII level greater 200%, and baseline vWF level greater than 200%. For each 1-point increase in score, the odds of persistent FVIII at both the 150% threshold (odds ratio [OR] = 10.4, 95% confidence interval [CI] 1.63-66.9, P = .0134) and 200% threshold (OR = 10.2, 95% CI 1.82-57.5, P = .0083) increased 10 times. Conclusion Because an elevated FVIII level confers increased stroke risk, our model for anticipating a persistently elevated FVIII level may identify patients at high risk for recurrent stroke. FVIII may be a target for secondary stroke prevention.

Men with hemophilia were initially thought to be protected from cardiovascular disease (CVD), but it is now clear that atherothrombotic events occur. The primary objective of the CVD in Hemophilia study was to determine the prevalence of CVD and CVD risk factors in US older men with moderate and severe hemophilia and to compare findings with those reported in age-comparable men in the Atherosclerosis Risk in Communities (ARIC) cohort. We hypothesized if lower factor levels are protective from CVD, we would see a difference in CVD rates between more severely affected and unaffected men. Beginning in October 2012, 200 patients with moderate or severe hemophilia A or B (factor VIII or IX level ≤ 5%), aged 54 to 73 years, were enrolled at 19 US hemophilia treatment centers. Data were collected from patient interview and medical records. A fasting blood sample and electrocardiogram (ECG) were obtained and assayed and read centrally. CVD was defined as any angina, any myocardial infarction by ECG or physician diagnosis, any self-reported nonhemorrhagic stroke or transient ischemic attack verified by physicians, or any history of coronary bypass graft surgery or coronary artery angioplasty. CVD risk factors were common in the population. Compared with men of similar age in the ARIC cohort, patients with hemophilia had significantly less CVD (15% vs 25.8%; P < .001). However, on an individual patient level, CVD events occur and efforts to prevent cardiovascular events are warranted. Few men were receiving secondary prophylaxis with low-dose aspirin, despite published opinion that it can be used safely in this patient population.

Characteristics of inhibitors identified by prospective screening may differ from those detected clinically. In a prospective study at 17 hemophilia centers with central inhibitor measurement by Nijmegen-Bethesda assay, 23 (2.8%) of 824 hemophilia A patients had new inhibitors detected: nine high-titer inhibitors (HTI: 7 ≥5.0 NBU plus 2 of 2.6 and 3.4 NBU at immune tolerance induction initiation) and 14 low-titer inhibitors (LTI: 0.5–1.9 NBU). HTI occurred at an earlier age (median 2 years, range 1–18, vs. median 11 years, range 2–61, P = 0.016). Both HTI (22%) and LTI (43%) occurred in non-severe patients. All HTI, but only 64% of LTI, were found to be FVIII-specific by chromogenic Bethesda assay or fluorescence immunoassay (FLI), indicating a high rate of false-positive LTI. Repeat specimens confirmed all HTI, 7/9 LTI, and 7/7 FVIII-specific LTI. FLI results were similar between HTI and FVIII-specific LTI; all included IgG1 and IgG4 subclasses. A comparable prospective study conducted from 1975 to 1979 at 13 U.S. centers found 31 (2.4%) new inhibitors among 1,306 patients. In both studies, one-third of inhibitors occurred in non-severe patients and one-quarter after 150 exposure days (ED). Significant differences were seen in the age at which inhibitors occurred (median 16 years in the older study vs. 5 years currently, P = 0.024) and in ED before inhibitor development, 10% in the older study and 43% currently study occurring within 20 ED, suggesting a temporal change in inhibitor development. Prospective screening detects inhibitors in patients of all severities, ages, and ED. Some LTI, however, are false positives.

Inhibitor development poses a significant challenge in the management of hemophilia because once an inhibitor is present, bleeding episodes can no longer be treated with standard clotting factor replacement therapy. Consequently, patients with inhibitors are at increased risk for difficult-to-control bleeding and complications, particularly arthropathy and physical disability. Three clinical trials in patients with inhibitors have demonstrated that prophylaxis with a bypassing agent reduces joint and other types of bleeding and improves health-related quality of life compared with on-demand bypassing therapy. In hemophilia patients without inhibitors, the initiation of prophylaxis with factor (F) VIII or FIX prior to the onset of recurrent hemarthroses can prevent the development of joint disease. Whether this is also true for bypassing agent prophylaxis remains to be determined.

Von Willebrand factor (VWF) contains binding sites for platelets and for vascular collagens to facilitate clot formation at sites of injury. Although previous work has shown that VWF can bind type IV collagen (collagen 4), little characterization of this interaction has been performed. We examined the binding of VWF to collagen 4 in vitro and extended this characterization to a murine model of defective VWF-collagen 4 interactions. The interactions of VWF and collagen 4 were further studied using plasma samples from a large study of both healthy controls and subjects with different types of von Willebrand disease (VWD). Our results show that collagen 4 appears to bind VWF exclusively via the VWF A1 domain, and that specific sequence variations identified through VWF patient samples and through site-directed mutagenesis in the VWF A1 domain can decrease or abrogate this interaction. In addition, VWF-dependent platelet binding to collagen 4 under flow conditions requires an intact VWF A1 domain. We observed that decreased binding to collagen 4 was associated with select VWF A1 domain sequence variations in type 1 and type 2M VWD. This suggests an additional mechanism through which VWF variants may alter hemostasis.

Acquired hemophilia A (AHA) is a rare disease resulting from autoantibodies (inhibitors) against endogenous factor VIII (FVIII) that leads to bleeding, which is often spontaneous and severe. AHA tends to occur in elderly patients with comorbidities and is associated with high mortality risk from underlying comorbidities, bleeding, or treatment complications. Treatment, which consists of hemostatic management and eradication of the inhibitors, can be challenging to manage. Few data are available to guide the management of AHA-related bleeding and eradication of the disease-causing antibodies. Endorsed by the Hemostasis and Thrombosis Research Society of North America, an international panel of experts in AHA analyzed key questions, reviewed the literature, weighed the evidence and formed a consensus to update existing guidelines. AHA is likely underdiagnosed and misdiagnosed in real-world clinical practice. Recommendations for the management of AHA are summarized here based on the available data, integrated with the clinical experience of panel participants.

Introduction: Baseline elevated Factor VIII (FVIII) level is a significant independent predictor of stroke occurrence and severity. We conducted a prospective serial laboratory cohort study to assess the correlation of FVIII levels in response to thrombolysis in patients with large vessel occlusion (LVO) and acute ischemic stroke (AIS). Methods: AIS patients with anterior circulation LVO were enrolled within 4.5 hours from last seen normal. Baseline and serial FVIII levels were obtained to determine whether FVIII serves as a surrogate marker of clot burden and if FVIII levels or changes predict (1) recanalization with intravenous tissue plasminogen activator (IV tPA) or (2) symptomatic intracranial hemorrhage (sICH) following tPA. Linear and logistic regression analyses were used to determine significant predictors. Results: Patients (n=29) had a mean age of 71years, median NIHSS of 15, 62% were of black race and 48% were female. Baseline pre -tPA FVIII was not significantly correlated with clot burden score (-0.15, p=0.45) or vessel recanalization (-0.13, p=0.50). Median FVIII decreased significantly from baseline to 6hrs post-tPA (282% to 161%, p=0.0024), but delta in FVIII level did not correlate with vessel recanalization (0.01, p=0.95). No patient had sICH. There was no difference between median FVIII level at baseline and 90 days post AIS. Interpretation: FVIII level decreased significantly after tPA, but baseline FVIII level and early change in FVIII level were not significant predictors of clot burden, vessel recanalization after treatment with IV tPA, or symptomatic hemorrhage. This trial provided no evidence to support the value of acute FVIII level as a biomarker in AIS due to LVO. The physiology behind the decrease in FVIII level after tPA remains unknown.

The correlation between real-world clinical decisions and adherence to published treatment algorithms for problem bleeding episodes in patients with severe hemophilia and inhibitors and the resultant impact on clinical outcomes were assessed. Nine cases documenting treatment for problem bleeding episodes in patients with severe hemophilia and inhibitors were retrospectively reviewed. Adherence to treatment algorithms was rated on a scale of 1 to 5, 1 being no adherence and 5 being very high adherence. Adherence ratings >3 were assigned to 7 cases in which high adherence was associated with ≤4 days to achieve hemostatic control; hospitalization for ≤7 days was noted in 6 of these cases. In cases rated ≤3 (n = 2), time to hemostatic control ranged from 5 to 8 days and hospitalization duration ranged from 10 to 16 days. These findings suggest that adherence to treatment algorithms may be beneficial in treating problem bleeding events in patients with hemophilia and inhibitors.

Background Patients with congenital Factor XIII (FXIII) deficiency have impaired fibrin stabilization and are at high risk for surgical bleeding. Data regarding the use of FXIII concentrates before and during surgery are lacking. The objective of this study was to report the use of plasma-derived FXIII concentrate (Corifact in the United States; Fibrogammin P in other countries) in patients with congenital FXIII deficiency undergoing surgical procedures. Study Design and Methods FXIII concentrate at preoperative doses ranging from 25 to 40 U/kg was administered to six patients with congenital FXIII deficiency undergoing major or minor surgeries. Results FXIII concentrate was administered immediately before surgery for five surgical cases; three of these patients achieved excellent hemostasis during and after surgery, while two had intraoperative bleeding. In one surgical case, a regular prophylactic dose of FXIII concentrate was administered to the patient 1 week before minor surgery. FXIII concentrate provided rapid replacement of FXIII activity. In all but one of the patients given a dose of FXIII designed to increase FXIII levels more than 50%, there was satisfactory intraoperative and postoperative hemostasis. One patient undergoing aortic valve replacement on cardiopulmonary bypass (CPB) was the exception. Intraoperative bleeding in this patient was associated with lower-than-expected blood levels of FXIII. Conclusion Preoperative plasma-derived FXIII concentrate allowed for sufficient hemostasis in most patients with FXIII deficiencies. Additional doses were necessary to achieve hemostasis in one patient who underwent a CPB procedure.

Adults with bleeding disorders may present to their family physician with minor bleeding symptoms or hematologic laboratory abnormalities discovered during evaluation for surgery or another purpose. Identifying the small proportion of adults who have an underlying bleeding disorder as the cause for such signs or symptoms may be challenging. In cases of asymptomatic hematologic laboratory abnormalities, the particular abnormality should narrow down the potentially affected hemostatic component(s), ideally streamlining subsequent investigation. In patients presenting with bleeding symptoms, a thorough history and physical examination are critical for first identifying bleeding as pathologic, then performing the appropriate diagnostic evaluation after excluding identifiable causes. Knowledge of the pathophysiologic processes contributing to impaired hemostasis in any given bleeding disorder ensures proper treatment and avoids therapies that are unnecessary or even contraindicated. Management is further determined by bleeding phenotype and, for invasive procedures, the anticipated risk for bleeding. Consultation with a hematologist may facilitate proper evaluation and treatment, particularly in adults with rare bleeding disorders or no identifiable cause for bleeding. This article reviews the diagnostic approach to hematologic laboratory abnormalities and abnormal bleeding in adults, as well as basic preventive care and hemostatic management of adults with bleeding disorders.

SummaryThe development of antibodies against infused factor VIII (FVIII) in patients with haemophilia A is a serious complication leading to poorly controlled bleeding and increased morbidity. No treatment has been proven to reduce high titre antibodies in patients who fail immune tolerance induction or are not candidates for it. The Rituximab for the Treatment of Inhibitors in Congenital Hemophilia A (RICH) study was a phase II trial to assess whether rituximab can reduce anamnestic FVIII antibody (inhibitor) titres. Male subjects with severe congenital haemophilia A and an inhibitor titre ≥5 Bethesda Units/ml (BU) following a FVIII challenge infusion received rituximab 375 mg/m2 weekly for weeks 1 through 4. Post-rituximab inhibitor titres were measured monthly from week 6 through week 22 to assess treatment response. Of 16 subjects who received at least one dose of rituximab, three (18.8%) met the criteria for a major response, defined as a fall in inhibitor titre to Trial: “Rituximab for the Treatment of Inhibitors in Congenital Hemophilia A: The RICH Study. Registered as Clinical Trials.gov identifier- NCT00331006.

Optimal management of coronary artery disease (CAD) in patients with von Willebrand disease (VWD) is a rare but challenging clinical scenario given the risk of potential bleeding and the lack of evidence-based guidance. We present a case of a patient with VWD who underwent successful complex

Introduction: Over a three-year period, U.S. men with hemophilia were found to be 50 times more likely to die from renal disease than the general population (SMR 50; 95% CI 26.8-92.8) (Soucie et al., Blood 2000). Despite this finding, data regarding chronic kidney disease (CKD) and its risk factors in patients with hemophilia remain limited. The objective of this study is to determine the prevalence of CKD and CKD risk factors among older men with moderate and severe hemophilia. Methods: This CKD cohort study is an extension of a U.S. national study sponsored by the American Thrombosis and Hemostasis Network (ATHN). The study, entitled ATHN 1: A Cross-Sectional Analysis of Cardiovascular Disease (CVD) in the Hemophilia Population, began enrollment in 10/2012. Inclusion criteria are men with moderate or severe congenital hemophilia A or B (FVIII or IX level ≤ 5%), age 54-73. Men with an additional bleeding disorder (besides liver dysfunction) were excluded. In this extension study, CKD risk factors, historical creatinine levels, and history of renal events were obtained from patient interview and chart review after obtaining informed consent. Glomerular filtration rate (GFR) values were calculated using the CKD-EPI equation and compared to values in the general population using the NHANES dataset (Coresh et al., JAMA 2007). CKD is defined as the presence of either kidney damage or decreased kidney function with GFR < 60 ml/min/1.73 m2 for ≥ 3 months, irrespective of cause. Results: As of 6/30/2018, 134/200 planned subjects have been enrolled and interim analysis on 134 subjects from 18 U.S. hemophilia treatment centers (HTCs) is presented here. The majority were white (119; 88.8%) or African-American (13; 9.7%). Mean age was 64 years (SD: 5; range: 56-77). Most used factor on demand, with only 38.8% (52/134) on prophylaxis, defined as ≥2 doses of FVIII or ≥ 1 dose FIX/week. Four (3.0%) had a current inhibitor. Viral infection was common; 28.4% currently had hepatitis C, and 19.4% HIV. Hypertension (HTN) was reported in 51.5% of subjects, 14.9% diabetes mellitus (DM); and average BMI was 28.2 kg/m2 (36.6% obese). 11.6% (16/134) were found to have CVD (defined as angina, MI, TIA, or ischemic or embolic stroke). Acute kidney injury was common. Fasting blood work showed an abnormally elevated creatinine in 26.9% subjects (mean 1.1 mg/dl, SD 0.4). Mean historical maximum creatinine reported in the cohort was 1.0 (range 0.5-4.8), with mean GFR 67 (range 11-126). 11.4% (13/114) met the definition of CKD. Stages of CKD by GFR in the hemophilia cohort were similar to the NHANES general population (p=0.561). See Table 1 for subject reported history of renal events, and Table 2 for specific diagnoses of renal disease. In our cohort, hemophilia subjects with CKD tended to have a diagnosis of intrinsic kidney disease (60.0% vs 11.6%, p=0.02), and non-significantly tended to have DM (23.1% vs 12.8%), age ≥65 years (21.1% vs 9.4%), and HTN (18.0% vs 9.8%) compared to subjects without CKD. No other significant trends were identified, including no association with CVD, HCV, HIV, BMI, or hematuria. Conclusions: In this interim analysis of an ongoing national prospective cohort study, older men with moderate to severe hemophilia commonly report risk factors for CKD, including HTN (51.5%), DM, viral infection, and potential renal damaging medication use. Only 11.6% had CVD. Urological symptoms were also common, including hematuria and obstructive symptoms with urination. In our cohort, 11.4% met the definition of CKD, defined as the presence of either kidney damage or GFR < 60 ml/min/1.73 m2 for ≥ 3 months. The distribution of GFR values appeared similar to the general population. As with risk factors associated with CKD in the general population, diagnosis of intrinsic kidney disease was significantly associated with CKD in hemophilia subjects, with non-significant trend for increased DM, older age, and HTN compared to subjects without CKD. It is reassuring that the prevalence of CKD does not appear to be increased in men with hemophilia compared to the general population, despite a known and unexplained high incidence of HTN in the hemophilia population. We plan to formally compare the prevalence of CKD and CKD risk factors with similarly aged men in the ARIC database once enrollment is complete, as understanding the risk factors that contribute to CKD is essential to halt its progression. Disclosures Sood: Bayer: Research Funding. Shapiro:BioMarin: Research Funding; Shire: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees, Research Funding; Prometic Life Sciences: Consultancy, Research Funding; Kedrion Biopharma: Consultancy, Research Funding; Sangamo Biosciences: Consultancy; Octapharma: Research Funding; OPKO: Research Funding; Daiichi Sankyo: Research Funding; Bayer Healthcare: Other: International Network of Pediatric Hemophilia; Bio Products Laboratory: Consultancy; Genetech: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Bioverativ, a Sanofi Company: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Kessler:Biomarin: Research Funding; Dimension Advisory boards: Membership on an entity's Board of Directors or advisory committees; DSMB: Membership on an entity's Board of Directors or advisory committees; Sangamo: Research Funding; Novo Nordisk: Honoraria, Research Funding; Octapharma: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Research Funding; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bayer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Key:UniQure BV: Research Funding. Quon:Bioverativ, a Sanofi Company: Speakers Bureau; NovoNordisk: Consultancy, Speakers Bureau; Bayer: Consultancy; Shire: Speakers Bureau; Genetech: Consultancy, Speakers Bureau; Octapharma: Consultancy. Manco-Johnson:Novo Nordisk: Honoraria; CSL Behring: Honoraria; Bayer AG: Honoraria, Research Funding; Biogentek: Honoraria; Baxalta, now part of Shire: Honoraria. Cuker:Kedrion: Membership on an entity's Board of Directors or advisory committees; Genzyme: Consultancy; Spark Therapeutics: Research Funding; Synergy: Consultancy. Ragni:Novo Nordisk: Research Funding; Shire: Research Funding; MOGAM: Membership on an entity's Board of Directors or advisory committees; Sangamo: Research Funding; Alnylam: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sangamo: Research Funding; SPARK: Consultancy, Research Funding; CSL Behring: Research Funding; Biomarin: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bioverativ: Consultancy, Research Funding; SPARK: Consultancy, Research Funding. von Drygalski:UniQure BV, Bayer, Bioverativ/Sanofi, Pfizer, Novo Nordisk, Biomarin, Shire, CSL Behring: Consultancy. Kouides:UniQure: Other: DSMB; Octapharma: Research Funding. Escobar:Bayer, CSL Behring, Genentech, Hemabiologics, Kedrion, Novo Nordisk, Octapharma, Pfizer and Shire: Consultancy; Pfizer: Research Funding. Wang:Daiichi Sankyo: Consultancy, Other: Travel. Konkle:Shire: Research Funding; Genentech: Consultancy; Bioverativ: Research Funding; BioMarin: Consultancy; Pfizer: Research Funding; Gilead: Consultancy; Spark: Consultancy, Research Funding; CSL Behring: Consultancy; Sangamo: Research Funding.

Background: Diagnosis of von Willebrand disease (VWD) is challenging in clinical practice due to variability in laboratory testing and clinical bleeding history. We investigated the prospective diagnosis of VWD in academic hematology clinics across the U.S. and Kingston, ON and report on the final cohort here. Methods: Subjects were enrolled as new consults to their hematologist for evaluation of a bleeding disorder from 11 centers. Laboratory results including VWF antigen (VWF:Ag) and VWF platelet binding activity were determined both locally (VWF ristocetin cofactor activity [VWF:RCo] or VWF:GPIbM) and centrally (VWF:GPIbM) to determine the comparative effectiveness in VWD diagnosis. Some centers defined type 1 VWD with levels Results: A total of 1826 subjects undergoing evaluation for VWD or a suspected bleeding disorder were prospectively enrolled. Median age, demographics, and bleeding score did not differ between the VWD and non VWD groups. Since pediatric subjects comprised a large segment of our cohort, bleeding scores were examined for subjects ≥18 years old and showed no difference with a median of 7 for those with and without VWD (p=NS). Subjects with VWD had no significant difference in VWF:Ag between local and central lab testing. Differences in VWF platelet binding was likely due to most local labs using VWF:RCo vs central lab testing with VWF:GPIbM. The diagnosis of VWD was determined locally. A total of 36% of subjects received a diagnosis of VWD. Of those, 63% received a diagnosis of type 1 VWD, 27% low VWF and 10% other (type 2A, 2B, 2M, 2N, 3 or unclassified). The percent of subjects with VWD was consistent across centers. One subject was diagnosed as type 3 VWD. For type 2 VWD, 4% were 2A, 1% 2B, 2% 2M, and We then separated these subjects into 3 groups by diagnostic testing: 1) type 1 VWD (using criteria of VWF:Ag or activity When both local and central lab results were taken into account and study definitions applied, only 29% of the enrolled subjects had abnormal VWF levels. Of these, 78% had low VWF, 15% type 1, and 7% type 2 VWD. Median bleeding score for both the low VWF and type 1 cohorts was 4 (p=NS). Type 2 subjects with confirmed phenotypic diagnoses had a median bleeding score of 5 (p=NS compared to the type 1 or low VWF cohorts). Discussion: This unique large prospective study of bleeding disorder subjects, designed as an inception cohort, highlights the diagnosis of VWD but presents several clinical challenges: 1) The lack of difference in bleeding scores between VWD and non VWD suggests that bleeding symptoms are common and possibly due to other diagnoses or not necessarily related to VWF levels. 2) The variability in VWD diagnosis with borderline levels is common when local and central lab testing are applied, potentially due to varying use of the VWF:RCo vs VWF:GPIbM to assess platelet binding activity. The comparative effectiveness of methods of diagnosis will be highlighted by followup testing on these subjects. 3) As only 1/3 of subjects merited a VWD or low VWF diagnosis, mild bleeding may be the result of other conditions; platelet defects, vascular disorders, collagen defects, other unidentified mechanisms or potentially non-pathogenic. We hypothesize that the presence of bleeding symptoms increases the likelihood that a diagnosis of VWD will be made, regardless of the level. This cohort will continue to be followed longitudinally which may help elucidate the importance of serial VWF measurement. However, the stability of VWD diagnosis across centers in 1/3 of subjects suggests a broader application. Disclosures Friedman: Shire: Membership on an entity's Board of Directors or advisory committees; CSL Behring: Membership on an entity's Board of Directors or advisory committees. James:Bayer: Research Funding; Shire: Research Funding; CSL Behring: Research Funding. Ragni:CSL Behring: Research Funding; Bioverativ: Consultancy, Research Funding; Shire: Research Funding; Biomarin: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sangamo: Research Funding; MOGAM: Membership on an entity's Board of Directors or advisory committees; Alnylam: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novo Nordisk: Research Funding; SPARK: Consultancy, Research Funding. Rajpurkar:HEMA biologics: Honoraria; Bristol Myers Squibb: Research Funding; Shire: Honoraria; Pfizer: Honoraria, Research Funding; Novonordisk: Honoraria. Shapiro:Shire: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Octapharma: Research Funding; Sangamo Biosciences: Consultancy; Bioverativ, a Sanofi Company: Consultancy, 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; OPKO: Research Funding; Bio Products Laboratory: Consultancy; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees, Research Funding; BioMarin: Research Funding; Daiichi Sankyo: Research Funding; Bayer Healthcare: Other: International Network of Pediatric Hemophilia; Kedrion Biopharma: Consultancy, Research Funding; Prometic Life Sciences: Consultancy, Research Funding. Sidonio:genentech: Membership on an entity's Board of Directors or advisory committees, Research Funding; shire: Membership on an entity's Board of Directors or advisory committees, Research Funding; bioverativ: Membership on an entity's Board of Directors or advisory committees, Research Funding; octapharma: Membership on an entity's Board of Directors or advisory committees; grifols: Membership on an entity's Board of Directors or advisory committees, Research Funding; biomarin: Membership on an entity's Board of Directors or advisory committees; uniqure: Membership on an entity's Board of Directors or advisory committees; csl behring: Membership on an entity's Board of Directors or advisory committees; novo nordisk: Membership on an entity's Board of Directors or advisory committees. Montgomery:BCW: Patents & Royalties: GPIbM assay patent to the BloodCenter of Wisconsin. Abshire:CSL: Consultancy; Shire: Consultancy; Novo Nordisk: Other: DSMB.

Introduction Hemophilia is an X linked disorder characterized by an increased tendency to spontaneous bleeding resulting from profound compromise of the hemostatic response with delayed development of a clot and the formation of clots that are vulnerable to fibrinolysis. Optimization of clot stability by adding TXA to low concentrations of factor concentrates may be a way to improve prophylaxis in patients with severe hemophilia (sH) without substantially increasing the cost or the burden of more frequent infusions. Aims We proposed to study whether hemostasis is improved with the addition of TXA to low FVIII plasma concentrations (equivalent to trough levels in prophylactic setting). We specifically studied in vitro the clot stability in patients with sHA; and in vivo the hemostatic response to trauma-induced joint bleed and tail clip in FVIII knock-out (KO) mice. Methods After obtaining informed consent, blood samples of 12 adults with sHA were spiked in vitro to achieve final concentrations (FC) of 0-3-10 and 30 IU/dL of FVIII, then studied with and without TXA at FC 0.1mg/ml. Whole blood (WB) was assessed with ROTEM performed after addition of tPA in 6 patients. Thrombin generation (TG) was measured in plasma (PL) of 6 other patients. Clots obtained from TG were examined under electron microscopy (EM) to evaluate the quality of fibrin clot structure. Diameters of randomly selected 100 fibrin fibers were measured in each clot. In animal studies, 13 FVIII KO mice were given FVIII to a plasma concentration of 3 IU/dL to mimic trough FVIII levels in prophylactic setting; 7 were also infused with TXA (FC 0.1mg/ml). 10 minutes after infusion, joint bleeding was induced by knee puncture using a standardized protocol. 2 days post trauma, MRI was done and the joint bleed (surface of hyper signal into the joint) was compared between the groups with and w/o TXA. 10 other FVIII KO mice were infused with 3 IU/dL rFVIII, of which 5 were also infused with TXA (FC 0.1mg/ml). 10 minutes after infusion, the extremity of the tail was cut at 2mm, and then immersed in pre-heated water-filled tube at 37°C. Blood was collected during 10 minutes. After lysis of erythrocytes, the amount of hemoglobin in collected blood was measured using spectrophotometry; means of optical density (OD) were compared between the 2 groups. Results A dose dependent improvement of TG was observed after adding FVIII alone (p=0.024). As expected, the addition of TXA had no effect on TG capcity. Fibrin fiber diameters were significantly decreased with TXA+FVIII compared to FVIII alone (results shown in fig1), suggesting a stronger fibrin network, as thin fibrin fibers are characteristic of a robust fibrin mesh. Surprisingly, ROTEM was fully normalized after addition of TXA only, with no exogenous FVIII. In FVIII KO mice, the addition of TXA to 3 IU/dL rFVIII significantly decreased joint bleeding compared to 3 IU/dL rFVIII alone (p=0.022) (fig2).With the tail clip experiment, the addition of TXA to 3 IU/dLFVIII showed a trend toward improved bleeding when compared to 3 IU/dLFVIII alone; with means of OD±SEM 0,31±0,19 and 0,94±0,45 respectively, but did not reach statistical significance (p=0,15) (fig3). Conclusion Our in vitro and in vivo results suggest a potential benefit of TXA when used in combination with FVIII in prophylactic setting. Disclosures No relevant conflicts of interest to declare.

Bleeding disorders, including haemophilia, von Willebrand disease, and platelet function abnormalities pose a substantial, ongoing management challenge. Patients with these disorders not only require treatment during bleeding events but also need effective management strategies to prepare for events ranging from minor dental procedures to major surgery and childbirth. Moreover, women with bleeding disorders often require ongoing treatment to prevent menorrhagia during childbearing years. Desmopressin (DDAVP), a synthetic derivative of the antidiuretic hormone l-arginine vasopressin, has become a well-established tool for the management of patients with bleeding disorders in a variety of clinical settings. However, despite the widespread use of DDAVP, the available clinical evidence on its efficacy and safety in these settings is limited, and there has not been a recent comprehensive review of its role in the clinical management of patients with bleeding disorders. As such, this article provides a review of the mechanism of action and pharmacokinetic properties of DDAVP, followed by a concise summary of the available evidence for its use in the treatment and prevention of bleeding.

PubMedID: 23731246 Patients with haemophilia A and inhibitors are at high risk for severe bleeding, progression of joint disease and deterioration of health-related quality of life (HRQoL). To determine the impact of prophylaxis with an activated prothrombin complex concentrate (aPCC) on HRQoL, HRQoL was assessed using the Short-Form (SF)-36 Health Survey and the EQ-5D questionnaire in subjects ?14 years participating in a prospective, randomized, crossover study comparing 6 months of aPCC prophylaxis with 6 months of on-demand therapy. Eighteen of 19 patients completed the survey or questionnaire before and after the on-demand therapy and prophylaxis periods. A general trend towards improved HRQoL after prophylaxis was observed for the 18 evaluable patients in all SF-36 dimensions except for vitality/energy and physical functioning. After prophylaxis, 'good responders,' defined as patients experiencing ?50% reduction in bleeding, exhibited statistically and clinically significant differences in the physical component score (P = 0.021), role - physical (P = 0.042), bodily pain (P = 0.015), and social functioning (P = 0.036). Similarly, the EQ-5D health profile showed a trend towards improvement after prophylaxis in all evaluable patients. Among the good responders, improvements did not differ from those observed after on-demand treatment. EQ visual analogue scale values were slightly improved following prophylaxis for all evaluable patients and the EQ-5D utility index improved in the good responders only. During prophylaxis, patients missed significantly fewer days from school or work because of bleeding than during on-demand treatment (P = 0.01). In conclusion, by significantly reducing bleeding frequency in good responders, aPCC prophylaxis improved HRQoL compared with on-demand treatment. © 2013 John Wiley & Sons Ltd.

Background rVIII-SingleChain, a novel recombinant factor VIII (rFVIII), has been designed as a B-domain truncated construct with covalently bonded heavy and light chains, aiming to increase binding affinity to von Willebrand factor (VWF). Preclinical studies confirmed greater affinity for VWF, giving improved pharmacokinetic and pharmacodynamic properties compared with full-length rFVIII. Aim To investigate the pharmacokinetics of rVIII-SingleChain and compare them against those of full-length rFVIII. Methods This study enrolled 27 patients with severe haemophilia A in the AFFINITY clinical trial programme. After a 4-day washout period, all patients received a single infusion of 50 IU kg−1 octocog alfa (Advate®); after a ≥4-day postinfusion washout period, they received a single infusion of 50 IU kg−1 rVIII-SingleChain. Blood samples for pharmacokinetic assessments of each product were collected before infusion (predose) and at 0.5, 1, 4, 8, 10, 24, 32, 48 and 72 h postinfusion for both products. Results rVIII-SingleChain had a longer mean half-life (t1/2) (14.5 vs. 13.3 h), lower mean clearance (CL) (2.64 vs. 3.68 mL h−1 kg−1), higher mean residence time (20.4 vs. 17.1 h) and larger mean AUCinf (2090 vs. 1550 IU?h dL−1) than octocog alfa, respectively. The mean AUCinf after rVIII-SingleChain infusion was ~35% larger than after octocog alfa. A similar pattern was observed for AUC0-last. No serious adverse events or inhibitors were reported. Conclusions rVIII-SingleChain has a favourable pharmacokinetic profile compared with octocog alfa and was well tolerated. The prolonged t1/2, larger AUC and reduced CL of rVIII-SingleChain may permit longer dosing intervals, thereby improving patient adherence to prophylactic treatment.

Joint bleeding is the hallmark of severe haemophilia and the major cause of disability in patients with this coagulopathy. Repeated bleeding into the same joint can lead to chronic synovitis and progressive arthropathy. Radiosynovectomy is one option for the treatment of chronic haemophilic synovitis, but concerns about the risks of exposure to ionizing radiation have divided clinicians as to the safety and appropriate use of the procedure. This article presents two differing viewpoints, one from a pair of orthopaedic surgeons who collectively have performed more than 300 radiosynovectomies in patients with haemophilia. They maintain that radiosynovectomy is a simple, effective, safe and low-cost technique children and adults with chronic haemophilic synovitis. The other perspective is from an experienced haemophilia treater who directs a major US haemophilia treatment centre. She believes that unresolved questions about the safety of radiation exposure in children argue against the use of radiosynovectomy in paediatric patients with haemophilia.

Diagnosis and classification of VWD is aided by molecular analysis of the VWF gene. Because VWF polymorphisms have not been fully characterized, we performed VWF laboratory testing and gene sequencing of 184 healthy controls with a negative bleeding history. The controls included 66 (35.9%) African Americans (AAs). We identified 21 new sequence variations, 13 (62%) of which occurred exclusively in AAs and 2 (G967D, T2666M) that were found in 10%-15% of the AA samples, suggesting they are polymorphisms. We identified 14 sequence variations reported previously as VWF mutations, the majority of which were type 1 mutations. These controls had VWF Ag levels within the normal range, suggesting that these sequence variations might not always reduce plasma VWF levels. Eleven mutations were found in AAs, and the frequency of M740I, H817Q, and R2185Q was 15%-18%. Ten AA controls had the 2N mutation H817Q; 1 was homozygous. The average factor VIII level in this group was 99 IU/dL, suggesting that this variation may confer little or no clinical symptoms. This study emphasizes the importance of sequencing healthy controls to understand ethnic-specific sequence variations so that asymptomatic sequence variations are not misidentified as mutations in other ethnic or racial groups.

The primary goal of prophylaxis in patients with severe haemophilia is to convert the phenotype from severe to moderate and to prevent the development of chronic arthropathy. Prior studies have demonstrated that prophylaxis decreases episodes of joint bleeds and chronic arthropathy. Effectiveness depends on prescription of prophylaxis and adherence to the prescribed regimen. The aim of this study was to determine if prescription of prophylaxis for children with haemophilia and perceptions of adherence to prophylaxis have changed since publication of the Joint Outcome Study (JOS). A questionnaire was sent, in electronic and written formats, to health professionals who provide care to children with haemophilia at US haemophilia treatment centres (HTCs). The response rate was 56 of 128 (44%) of the targeted HTCs. There were a few missing data and denominators are provided. All responses agreed with the results of the JOS and 30/55 (55%) reported the JOS increased their prescription of prophylaxis. Nineteen of 56 (34%) physicians or HTC staff reported that they had not prescribed prophylaxis within the last year due to concerns about adherence, and 19/56 (34%) reported they had stopped prophylaxis due to concerns about adherence within the last year. Predicted adherence decreased with increasing age. Prescription of prophylaxis appears to be increasing since publication of the JOS. Strategies to improve adherence may increase the likelihood of physician prescription of prophylaxis and make prophylaxis easier to implement for individual patients, thereby improving the clinical outcome of children and adults with haemophilia.

Few data exist on the impact of age and inhibitor status on activity levels among patients with severe and moderately severe haemophilia A. The aim of this analysis was to assess the impact of age, race/ethnicity and inhibitor status on functional limitations through retrospective analysis of data from the Hemophilia and Thrombosis Research Society (HTRS) Registry. Functional status data from patients with haemophilia A with or without inhibitors who were enrolled in the HTRS Registry between October 1999 and July 2008 were analysed by age, race and ethnicity. Of the 2497 registrants, 1340 had congenital haemophilia A (333 with inhibitors). Functional status was available for 274 subjects with haemophilia A with current inhibitors and 247 subjects without inhibitors who had moderately severe (FVIII levels ≤ 2%). Functional impairment increased with age across five levels of functional status (P < 0.01). Inhibitors were associated with greater functional impairment in two age groups (13-21 years and older than 21 years) [unrestricted activity in 57.8% vs. 63.6% (P = 0.06) and 18.3% vs. 28.6% (P = 0.04), respectively]. Blacks had worse functional status than caucasians across all ages regardless of inhibitor status. Functional status decreases with age, and impairment is greater among patients with inhibitors beginning in adolescence. These results reaffirm the need for early eradication of inhibitors and early treatment of bleeds in inhibitor and non-inhibitor patients. This analysis highlights the benefit of ongoing study of these patients through data collected for the HTRS Registry.

The haemophilia literature increasingly contains reports describing the use of bypassing agent prophylaxis (BAP) in patients with severe haemophilia A and inhibitors. However, it is difficult to interpret and compare the results and draw conclusions about treatment efficacy because of small patient numbers and a lack of standardization among BAP studies. This article presents consensus recommendations for standardizing future BAP clinical trials developed by an international panel of haemophilia opinion leaders.

Patients with bleeding disorders such as hemophilia A, hemophilia B, and von Willebrand disease (VWD) are routinely treated at home, with their care managed in specialized centers. In emergency situations, these patients often present to their local emergency department (ED), where their management can represent a challenge to the emergency physicians and staff who rarely encounter them. Delays in diagnosis and administration of replacement therapy are the factors most commonly identified as predictive of death. Patients and family members are often very well educated in the disease and its management, which can significantly reduce morbidity and mortality. Children with bleeding disorders confer different challenges to the emergency physician and staff: they may present with no obvious signs of trauma or they may present with bruises consistent with non-accidental injury. All possible causes of bruising/bleeding should be investigated, although treatment should be administered promptly. The initial presentation of a bleeding disorder in the pediatric population is often made in the ED. Treatment of hemophilia A and B requires rapid replacement of the deficient clotting factor, with the desired factor level and dosage dependent on the product used and the hemorrhagic situation encountered. In patients with VWD, the main treatments are desmopressin or intravenous infusion of plasma-derived concentrates containing factor VIII and von Willebrand factor. The aim of this review is to outline some of the issues facing emergency physicians and the options available for the treatment of patients with hemophilia A, hemophilia B, and VWD.

L. A. VALENTINO,* M. CARCAO, P. MATHEW, C. A. LEISSINGER,§ E. BERNTORP,– V. BLANCHETTE, C. ESCURIOLA-ETTINGSHAUSEN,** B. EWENSTEIN, N. EWING, A. GRINGERI,§§ W. K. HOOTS–– and C. NEGRIER*** *Departments of Pediatrics and Internal Medicine, Rush University Medical Center, Chicago, IL, USA; Department of Pediatrics, Hospital for Sick Children, Toronto, ON, Canada; Department of Pediatrics, University of New Mexico Health Science Center, Albuquerque, NM, USA; §Louisiana Center for Bleeding and Clotting, Tulane University Medical Center, New Orleans, LA, USA; –Department of Coagulation Disorders, Malmo University Hospital, Malmo, Sweden; **Department of Pediatrics, J. W. Goethe University Hospital, Franklin, Germany; Baxter Bioscience, Westlake Village, CA, USA; Division of Pediatrics, City of Hope National Medical Center, Duarte, CA, USA; §§Bianchi Bonomi Hemophilia and Thrombosis Center, Milan, Italy; ––Department of Pediatrics, University of Texas Medical School, Houston, TX, USA; and ***Hemophilia Center, Hopital Edouart Herriot, Lyon, France

Over-anticoagulation is a common problem with warfarin therapy and can lead to major or life-threatening bleeding. The goal of urgent warfarin reversal is to elevate or replace vitamin K-dependent clotting factors. In the United States, fresh frozen plasma (FFP) is considered the standard of care for warfarin reversal. Prothrombin complex concentrates (PCCs) offer an alternative to FFP for rapidly replacing deficient clotting factors and correcting the international normalized ratio (INR). However, few prospective clinical trials have been conducted to evaluate the effectiveness of these concentrates relative to other treatment modalities. A review of the published literature over the last 30 years found that PCCs offer a rapid and specific method for replacing vitamin K-dependent clotting factors and restoring normal hemostasis in the context of over-coagulation. In those studies in which PCCs were compared with FFP, PCCs were found more effective in shortening the time to INR correction and were associated with a low risk of thrombotic adverse events. Evidence-based treatment guidelines are needed to optimize the use of PCCs for warfarin reversal.

Summary. This is the case of a 28-year-old man with severe congenital haemophilia A, who had a relatively mild bleeding course during early childhood, with limited factor VIII (FVIII) exposure. He was infected with HIV before the age of 7 years, and demonstrated profound immunodeficiency from childhood, with very low CD4+ cell counts for more than a decade. Following initiation of highly active anti-retroviral therapy (HAART) and gradually increasing CD4+ cells, he presented for the first time with a high-titre inhibitor at age 26, despite over 1000 previous FVIII exposures. Subsequently, his inhibitor was successfully eradicated with a standard immune tolerance protocol. It is likely that the effects of chronic HIV infection on T-lymphocyte pathways, and the partial immune reconstitution resulting from HAART, led to this patient’s unusual inhibitor course. Such a case serves to augment knowledge gained in animal studies about the immunobiology of FVIII inhibitors.

Summary. It is known that chronically ill patients adhere to medical treatment plans only 50% of the time [1]. Adherence to treatment with factor infusion therapy in haemophilia patients is essential to stop bleeding. It also prevents both acute and chronic life and limb threatening complications. This study, performed in a well-described haemophilia population, was completed in an effort to understand the critical issue of adherence in patients with haemophilia. A major component of the methodology of this study was the development of a unique scoring system to quantify adherence. Adherence scores in patients on On-Demand treatment strategies were then compared to those on High Intensity treatment strategies. Quality of life (QoL) studies were also performed on the study population to assess the association of treatment regimen and adherence scores to QoL measures. Results of this study demonstrated that adherence to On-Demand therapy was significantly greater than adherence to High Intensity treatment regimens and in children, High Intensity treatment regimens, which included prophylaxis, correlated with better QoL scores in body pain. It is envisioned that the development of an objective scoring system for adherence will prove useful in future studies of adherence as well as in the development of intervention strategies that can overcome barriers to adherence in haemophilia patients.

Effective ways to prevent arthropathy in severe hemophilia are unknown.We randomly assigned young boys with severe hemophilia A to regular infusions of recombinant factor VIII (prophylaxis) or to an enhanced episodic infusion schedule of at least three doses totaling a minimum of 80 IU of factor VIII per kilogram of body weight at the time of a joint hemorrhage. The primary outcome was the incidence of bone or cartilage damage as detected in index joints (ankles, knees, and elbows) by radiography or magnetic resonance imaging (MRI).Sixty-five boys younger than 30 months of age were randomly assigned to prophylaxis (32 boys) or enhanced episodic therapy (33 boys). When the boys reached 6 years of age, 93% of those in the prophylaxis group and 55% of those in the episodic-therapy group were considered to have normal index-joint structure on MRI (P=0.006). The relative risk of MRI-detected joint damage with episodic therapy as compared with prophylaxis was 6.1 (95% confidence interval, 1.5 to 24.4). The mean annual numbers of joint and total hemorrhages were higher at study exit in the episodic-therapy group than in the prophylaxis group (P0.001 for both comparisons). High titers of inhibitors of factor VIII developed in two boys who received prophylaxis; three boys in the episodic-therapy group had a life-threatening hemorrhage. Hospitalizations and infections associated with central-catheter placement did not differ significantly between the two groups.Prophylaxis with recombinant factor VIII can prevent joint damage and decrease the frequency of joint and other hemorrhages in young boys with severe hemophilia A. (ClinicalTrials.gov number, NCT00207597 [ClinicalTrials.gov].).

The presence of inhibitory antibodies to clotting factors complicates the treatment of bleeding in haemophilia patients. For patients with high-titre inhibitors, bypassing agents are essential to haemostatic management. To determine optimal treatment practices, an international panel of physicians convened to develop a systematic treatment approach for problem bleeds (i.e. bleeds that are unresponsive to initial therapy with a single agent within a reasonable amount of time) in haemophilia patients with inhibitors. AIM: The goal of this panel was to develop a consensus algorithm that would aid physicians in considering a variety of treatment approaches to optimize patient care by preventing extensive therapy with inadequate treatments that may lead to suboptimal patient outcomes and unnecessary costs. METHODS: Consensus opinions were analyzed for clinical preferences at different time periods, depending on patient response to treatment. Decision-making points were defined based on the type of bleed: every 8-12 h for the first 24 h, then every 24 h thereafter for limb-threatening bleeds; every 2-4 h for 2-7 days for life-threatening bleeds. RESULTS: The resultant consensus guidelines provide a generalized methodology to guide the treatment of problem bleeds in patients with severe haemophilia A and inhibitors, and emphasize changing treatment at the first sign of an inadequate haemostatic response. The treatment algorithms apply to both paediatric and adult patients, although the differences between the two groups were reviewed. CONCLUSION: These guidelines are focused on optimising the timing of treatment decisions, which may lead to faster responses and improved outcomes.

SummaryBolus infusion (BI) recombinant factor VIIa (rFVIIa) administration is safe and effective in the surgical management of haemophilia patients with inhibitors but has not been compared directly with continuous infusion (CI). We conducted an open-label, randomized, multicenter trial comparing the efficacy and safety of rFVIIa administered by BI or CI for the surgical management of haemophilia A or B patients with inhibitors to FVIII or FIX. Safety was compared with that of a control group of noninhibitor patients receiving FVIII or FIX concentrates for major surgery. All inhibitor subjects received an initial bolus dose of 90 μg/kg rFVIIa and were then randomly assigned to BI (n=12) or CI (n=12). The BI group received 90 μg/kg rFVIIa every two hours (h) during surgery through day 5, then every four hours for days 6–10. The CI group received 50 μg/kg/h rFVIIa through day 5, then 25 mg/kg/h for days 6–10. The control group (n=12) received FVIII or FIX per institutional protocols. Twenty-two major surgeries included orthopedic procedures on the knee (n=13), hip (n=3), and abdominal/pelvis procedures (n=4). One patient with an autoimmune FVIII inhibitor randomized to the BI arm was excluded from efficacy analysis. Haemostatic efficacy of rFVIIa in each group was comparable: effective in 8/11 and 9/12 subjects in the BI and CI arms, respectively, and ineffective in three subjects in each arm. Serious adverse events were related to continued or increased bleeding. In conclusion, haemostatic efficacy and safety of BI and CI of rFVIIa are comparable for the surgical management of haemophilia subjects with inhibitors.

SummaryPerioperative clotting factor replacement is administered to reverse the inherent haemostatic defect in persons with haemophilia (PWH), potentially increasing their risk for developing venous thromboembolism (VTE) postoperatively. It was our objective to determine the prevalence of VTE in PWH undergoing total hip or knee arthroplasty (THA, TKA). Patients with haemophilia A or B who underwent THA or TKA were enrolled in this prospective, multicentre observational cohort study. Lower extremity venous duplex ultrasound was performed prior to surgery and 4–6 weeks after surgery. Eleven centres enrolled 51 subjects, 46 of whom completed the study. Six subjects (13.0 %) were treated with bypass agents perioperatively; the remaining 40 subjects received factor VIII or IX replacement. Intermittent pneumatic compression devices were utilised postoperatively in 23 subjects (50 %), and four subjects (8.7 %) also received low-molecular-weight heparin prophylaxis. One subject (2.2 %) with moderate haemophilia A was diagnosed with symptomatic distal deep-vein thrombosis (DVT) on day 6 following TKA. One subject (2.2 %) with severe haemophilia A was diagnosed with pulmonary embolism on day 9 following bilateral TKA. No subjects had asymptomatic DVT. Eighteen subjects (39.1 %) had major bleeding, and three subjects (6.5 %) experienced minor bleeding. The observed prevalence of ultrasound-detectable, asymptomatic DVT in PWH following TKA or THA in this study was low, but the incidence of symptomatic VTE (4.3 %, 95 % CI, 0.5–14.8 %) appeared similar to the estimated incidence in the general population without thromboprophylaxis.

von Willebrand disease (VWD) is the most common inherited bleeding disorder, and type 1 VWD is the most common VWD variant. Despite its frequency, diagnosis of type 1 VWD remains the subject of debate. In order to study the spectrum of type 1 VWD in the United States, the Zimmerman Program enrolled 482 subjects with a previous diagnosis of type 1 VWD without stringent laboratory diagnostic criteria. von Willebrand factor (VWF) laboratory testing and full-length VWF gene sequencing was performed for all index cases and healthy control subjects in a central laboratory. Bleeding phenotype was characterized using the International Society on Thrombosis and Haemostasis bleeding assessment tool. At study entry, 64% of subjects had VWF antigen (VWF:Ag) or VWF ristocetin cofactor activity below the lower limit of normal, whereas 36% had normal VWF levels. VWF sequence variations were most frequent in subjects with VWF:Ag

Acquired hemophilia A is a rare autoimmune disorder caused by an autoantibody (inhibitor) to factor VIII (FVIII) that interferes with its coagulant function and predisposes to severe, potentially life-threatening hemorrhage. Disease management focuses on controlling bleeding, primarily with the use of bypassing therapy and recombinant porcine FVIII, and permanently eradicating the autoantibody using various immunosuppressants. Treatment challenges include delayed diagnosis, difficulty achieving hemostasis and durable remissions, and complications associated with the use of hemostatic and immunosuppressive therapy in a primarily older patient population.