Search

INTRODUCTION Guidelines of the World Federation of Hemophilia support the provision of equitable, optimal care for people with hemophilia (PWH). However, limited research exists examining the lived experiences of PWH or the barriers to care they may encounter. The primary objective of this exploratory study was to describe the experiences of men with hemophilia in Canada. METHODS We conducted a qualitative descriptive study using a semistructured interview guide and analyzed transcribed interviews using inductive thematic content analysis. Inclusion criteria were: age ≥18 years, English-speaking, and confirmed diagnosis of inherited hemophilia A or B. RESULTS A total of 11 participants were interviewed. Median age was 39 years old (29-73 years old), and diagnoses included severe hemophilia A (n = 5), mild hemophilia A (n = 2), and severe hemophilia B (n = 4). Three primary themes arose: (1) impact on identity and daily life; (2) dynamic changes in treatment; and (3) barriers to care and identified needs. Major subthemes included chronic pain and activity limitation, psychosocial burden, and symptom normalization. Multidisciplinary care, coordinated surgical care, improved emergency care, and clear care plans were identified as ongoing needs. DISCUSSION Men with hemophilia described significant symptom burden and areas of ongoing need. Collaborative efforts between hematologists, emergency room physicians, and surgeons to establish hospital-specific testing, treatment and referral guidelines, and regular hemophilia treatment center audits may help address these care gaps, providing more person-centered, equitable care. Future work is required to implement these strategies and monitor their effects.

Amy D Shapiro,1 Alejandro Fernandez,2 Jerome Teitel,3 Jaco Botha,2 Kate Khair4 1Indiana Hemophilia & Thrombosis Center, Indianapolis, IN, USA; 2Takeda Pharmaceutical International AG, Zürich, Switzerland; 3St. Michael’s Hospital, University of Toronto, Toronto, ON, Canada; 4Centre for Outcomes and Experience Research in Children’s Health Illness and Disability (ORCHID), Great Ormond Street Hospital, London, UKCorrespondence: Jaco BothaTakeda Pharmaceutical International AG, Thurgauerstrasse 130, Glattpark-Opfikon, Zürich, 8152, SwitzerlandTel +41 79 961 8561Email jaco.botha@takeda.comIntroduction: Neutralizing antibodies to coagulation factor VIII (FVIII) remain a major complication associated with FVIII replacement therapy.Aim: To assess safety and efficacy of immune tolerance induction (ITI) therapy with ADVATE® (antihemophilic factor [recombinant] [rAHF]) in patients who participated in the Prospective ADVATE Immune Tolerance Induction Registry (PAIR) study.Methods: The PAIR study was an international, multicenter, open-label, prospective, observational study in patients with hemophilia A and inhibitors, prescribed rAHF ITI therapy in clinical practice. The primary endpoint was adverse event (AE) reporting; the secondary endpoints included incidence of central venous access device-related complications and success rates of ITI therapy. Maintenance of immune tolerance was monitored for 12 months post-ITI therapy.Results: Of 44 patients, 36 completed ITI therapy, including 31 completing the 12-month follow-up. Most patients received rAHF 90– 130 IU/kg/day (59.1%) and a mean of 6.0 doses/week; the median duration of rAHF ITI therapy during the PAIR study was 600 days. Overall, 284 AEs were reported; 56 AEs were serious, of which none were considered rAHF-related. Of 228 nonserious AEs, 14 (in six patients) were deemed rAHF-related: increase of FVIII inhibitors titer due to anamnestic response, nausea, catheter site pain, pyrexia, urticaria, upper respiratory tract infection, arthralgia, and hemarthrosis. None were severe or led to ITI discontinuation. Eighteen patients experienced ≥ 1 central venous access device-related complication, and 21 of 36 completers achieved a negative inhibitor titer. The Kaplan–Meier estimate of success for achievement of first negative titer at 18 months of ITI therapy was 68.3% (95% confidence interval 51.8– 83.6%) among completers. Of patients with partial or complete success post-ITI, 87% (20/23) maintained immune tolerance at 12-month follow-up.Conclusion: Data suggest that rAHF ITI therapy in the PAIR study was effective, with no unexpected safety signals reported.Keywords: hemophilia A, immune tolerance, post-marketing product surveillance, therapeutics, adverse effects

Background The efficacy and safety of wilate (human von Willebrand factor/coagulation factor VIII) in patients with von Willebrand disease (VWD) has been demonstrated in clinical trials. Here, we present real-world data on the use of wilate for the routine care of patients with VWD. Objectives The objectives of this observational, prospective, phase 4 study were to evaluate the safety, tolerability, and effectiveness of wilate in on-demand treatment of bleeding episodes (BEs), long-term prophylaxis, and surgical prophylaxis among patients with any type of VWD. Methods Patients were enrolled at 31 study centers in 11 countries and followed for up to 2 years. Safety endpoints included adverse drug reactions (ADRs) and drug tolerability. Effectiveness was assessed using annualized bleeding rates (ABRs) during prophylaxis and predefined criteria for the treatment of BEs and surgical prophylaxis. Results A total of 111 patients (76 [68%] female) including 41 (37%) children were treated with wilate. Twenty-five patients received prophylaxis, 29 on-demand treatment, and 62 surgical prophylaxis. Tolerability was rated by patients as “excellent” for 96.2% of 6,497 infusions. No unexpected ADRs or thrombotic events were reported. Median ABR during prophylaxis was 1.9. Effectiveness was assessed as “excellent” or “good” by patients and investigators for 100% of BEs treated on-demand, 98% (patient rating) and 99% (investigator rating) of breakthrough BEs, and 99% of surgical procedures (investigator rating). Conclusion wilate was safe, well tolerated, and effective for the prevention and treatment of bleeding in pediatric and adult VWD patients in a real-world setting.

Background The use of pharmacokinetic (PK) studies to help design personalized prophylaxis regimens for factor VIII (FVIII) concentrate in individuals with hemophilia A has been recognized for many years but only became practical for routine clinical use with the availability of web‐accessible population PK applications based on Bayesian analysis. Objective To compare PK variables using population PK studies done on 2 extended half‐life recombinant FVIII concentrates in 23 individuals with hemophilia A after switching from one product to the other. Methods We retrospectively analyzed PK parameters derived from the Web‐Accessible Population Pharmacokinetic Service‐Hemophilia (WAPPS‐HEMO) application on 23 individuals with severe or moderately severe hemophilia A who were required to switch from recombinant FVIII Fc (Eloctate; Biogen, Cambridge, MA, USA) to recombinant antihemophilic factor PEGylated (Adynovate; Takeda Pharmaceutical Company, Osaka, Japan) between 2016 and 2017. Results There were minor PK differences between Eloctate and Adynovate, but some parameters did reach statistical significance, namely in vivo recovery (mean, 2.73 IU/dL per IU/kg vs 2.41 IU/dL per IU/kg), clearance (mean, 0.163 mL/h vs 0.194 mL/h), and volume of distribution at steady state (mean, 42.5 ml/kg vs 49.8 mL/kg). Smaller nonsignificant trends toward higher values for Adynovate were seen in terminal half‐life, area under the curve, and predicted times to 5% and 1% residual FVIII after infusion. Conclusion Population PK analysis revealed differences between the two extended half‐life FVIII concentrates, reaching significance for in vivo recovery, clearance, and volume of distribution.

Background Patients with type 1 von Willebrand disease (VWD) undergo a desmopressin (DDAVP) responsiveness challenge at diagnosis to assess whether DDAVP reverses their coagulation deficits. Current practice assumes DDAVP responsiveness remains constant over the lifetime. In patients with type 1 VWD, VWF‐related parameters increase with age. This study explores whether DDAVP responsiveness also differs with age in this population. Methods We conducted a retrospective chart review of 106 patients enrolled at our center since 1990. Our primary outcome was DDAVP responsiveness at 1 hour after DDAVP challenge. Locally weighted scatterplot smoothing fit and Spearman correlation coefficients were used to study the relationship between age and DDAVP responsiveness. For female participants, we used the Kruskal‐Wallis test to compare absolute and relative changes in DDAVP responsiveness at various ages. Results We had 79 patients (56 female) with type 1 VWD with at least 1 DDAVP challenge. In women with type 1 VWD, the absolute change in DDAVP responsiveness did not vary significantly with age (VWF:antigen [Ag], −0.08, P = .56; VWF:ristocetin cofactor [RCo], −0.16, P = .26; low‐molecular‐weight component of factor VIII [FVIII:C], −0.01, P = .93), nor did the relative change in DDAVP responsiveness (VWF:Ag, −0.03, P = .86; VWF:RCo, −0.25, P = .09; FVIII:C, −0.14, P = .34). The data plot suggested a relationship. Conclusion In women with type 1 VWD, DDAVP responsiveness may vary over the life cycle. Our exploratory findings are limited by our retrospective data, cross‐sectional design, and small sample. Future studies should investigate the relationship between age and DDAVP responsiveness prospectively to evaluate whether there is clinical utility in rechallenging postpubertal female patients with type 1 VWD.

Acquired hemophilia A (AHA), a rare bleeding disorder caused by neutralizing autoantibodies against coagulation factor VIII (FVIII), occurs in both men and women without a previous history of bleeding. Patients typically present with an isolated prolonged activated partial thromboplastin time due to FVIII deficiency. Neutralizing antibodies (inhibitors) are detected using the Nijmegen-modified Bethesda assay. Approximately 10% of patients do not present with bleeding and, therefore, a prolonged activated partial thromboplastin time should never be ignored prior to invasive procedures. Control of acute bleeding and prevention of injuries that may provoke bleeding are top priorities in patients with AHA. We recommend treatment with bypassing agents, including recombinant activated factor VII, activated prothrombin complex concentrate, or recombinant porcine FVIII in bleeding patients. Autoantibody eradication can be achieved with immunosuppressive therapy, including corticosteroids, cyclophosphamide and rituximab, or combinations thereof. The median time to remission is 5 weeks, with considerable interindividual variation. FVIII activity at presentation, inhibitor titer and autoantibody isotype are prognostic markers for remission and survival. Comparative clinical studies to support treatment recommendations for AHA do not exist; therefore, we provide practical consensus guidance based on recent registry findings and the authors’ clinical experience in treating patients with AHA.

The management of a patient with hemophilia undergoing cardiovascular surgery relies on accurate coagulation test results. Both unfractionated heparin (UFH) and protamine sulfate used during cardiac surgery can interfere with factor and inhibitor assays. Here we describe the effects of UFH and protamine sulfate on routine coagulation, factor activity, and inhibitor assays. Pooled normal plasma (PNP) with UFH, PNP with protamine sulfate, PNP with both protamine sulfate and UFH were tested for the activated partial thromboplastin time (aPTT), prothrombin time (PT), thrombin time (TT), UFH anti-Xa, one-stage factor VIII (FVIII) activity, one-stage factor IX (FIX) activity, and Bethesda inhibitor assays for FVIII and FIX. UFH had a dose-dependent effect with TT, aPTT, and PT. On Bethesda inhibitor testing, FIX inhibition was detected at 1 U/ml UFH and 3 U/ml UFH for FVIII. Increasing protamine sulfate concentration in PNP prolonged the PT and aPTT in a dose-dependent manner, decreased FVIII and FIX activity and did not affect TT or UFH anti-Xa. At protamine sulfate doses of at least 200 μg/ml there was weak FVIII and FIX inhibition detected. At lower ratios of protamine sulfate to UFH (0.6 : 1-0.8 : 1), the aPTT decreased, suggesting reversal of UFH. However, at protamine sulfate to UFH ratios of 1.0 : 1 and higher, aPTT prolongation was observed. Inhibition of FVIII and FIX was detected at low ratios of protamine sulfate to UFH (below 0.4 : 1) and disappeared at higher ratios. UFH and protamine sulfate, alone or in combination, impact factor activity and inhibitor testing for both FVIII and FIX. Hence, factor activity and inhibitor assay results should be interpreted with caution when UFH or protamine sulfate are present.

Background Acquired haemophilia (AH) is a rare bleeding disorder with significant morbidity and mortality. Most patients initially present to physicians without experience of the disease, delaying diagnosis and potentially worsening outcomes. Existing guidance in AH is limited to clinical opinion of few experts and does not address monitoring bleeds in specific anatomical locations. Aim Derive consensus from a large sample of experts around the world in monitoring bleeding patients with AH. Methods Using the Delphi methodology, a structured survey, designed to derive consensus on how to monitor bleeding patients with AH, was developed by a steering committee for completion by a group of haematologists with an interest in AH. Consensus was defined as ≥75% agreement with a given survey statement. After three rounds of survey refinement, a final list of consensus statements was compiled. Results Thirty-six global specialists in AH participated. The participants spanned 20 countries and had treated a median of 12.0 (range, 1-50) patients with AH within the preceding 5 years. Consensus was achieved in all items after three survey rounds. In addition to statements on general management of bleeding patients, consensus statements in the following areas were presented: urinary tract, gastrointestinal tract, muscles, skin, joints, nose, pharynx, mouth, intracranial and postpartum. Conclusions Here, we present consensus statements derived from a broad sample of global specialists to address monitoring of location-specific bleeds and evaluating efficacy of bleeding treatment in patients with AH. These statements could be applied in practice by treating physicians and validated by individual population surveys.

Introduction Women with inherited bleeding disorders experience excessive bleeding that may impair their quality of life, making early diagnosis and treatment critical. However, the experiences of these women regarding access to care has been minimally described. The primary objective of this study was to evaluate and describe barriers to care for women with bleeding disorders. This study was a continuation of our previous work describing the lived experiences of these women. Methods We undertook a qualitative descriptive study. Inclusion criteria for study enrollment were the following: age ≥ 18 years, English-speaking, and confirmed diagnosis of an inherited bleeding disorder. Women were recruited across Canada by treating healthcare providers and members of the Canadian Hemophilia Society. Telephone interviews were conducted using a semi-structured interview style, transcribed verbatim, and analyzed using descriptive thematic analysis. Results A total of 15 participants were interviewed. Median age was 31 years (range 24-70 years). Four primary themes surrounding barriers to care emerged: 1. Lack of healthcare provider awareness of bleeding disorders, 2. Healthcare provider dismissal of symptoms, 3. Limited access to specialized care and treatment plans, and 4. Need for self-education and advocacy. Discussion We found that women with inherited bleeding disorders experience tension with the healthcare system, feeling unheard and poorly understood. Based on our findings, we identified key knowledge and care gaps that could be addressed with awareness and educational initiatives: patient education on vaginal blood loss, updated medical curricula, clear referral guidelines, and tele-health initiatives for patients residing far from hemophilia treatment centres.

The treatment of bleeding in hemophilia A patients with persistent inhibitory antibodies to factor VIII is problematic. The current standard hemostatic agents for inhibitor patients are recombinant activated factor VII (rFVIIa) and activated prothrombin complex concentrate (APCC). These "inhibitor bypassing agents" are less reliably effective than are replacement therapies for patients without inhibitors, and there are no validated laboratory assays to monitor their efficacy. Furthermore, only single rFVIIa and APCC products are available worldwide, and their use can be complicated, albeit rarely, by thrombotic events. For all these reasons, new approaches to treat bleeding in inhibitor patients are eagerly awaited. These new approaches include replacement therapy with porcine factor VIII concentrate (currently approved for use in acquired hemophilia patients), bispecific antibodies to simulate the biologic function of factor VIII (already in use in some jurisdictions), pegylated forms of activated factor VII, and strategies targeting the natural anticoagulants TFPI and antithrombin, which create a hypercoagulable phenotype to counterbalance the hypocoagulability imposed by hemophilia.

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 Standard prophylaxis has been shown to be an effective treatment for severe haemophilia A. According to pharmacokinetic principles, daily factor infusions of smaller doses can maintain similar trough factor VIII (FVIII) levels, and perhaps the same protection as standard prophylaxis. Aim This multicentre study examined the feasibility of daily prophylaxis for youth and young adults with severe haemophilia A in Montreal and Toronto. Methods Bleeding rates, joint status, quality of life and physical activity were monitored for 14 patients during this study. At baseline, subjects continued their regular treatment regimen and switched to daily prophylaxis after 4 months; nine had begun daily prophylaxis before enrolment. Additional visits occurred at 8 and 12 months which included a physical examination, inhibitor testing, HJHS and FISH assessments, the CHO-KLAT/Haemo-QoL-A and PDPAR. Treatment satisfaction was assessed using the Treatment Satisfaction Questionnaire for Medication ver.II and perceived difficulty questions at the end of study. Results and conclusions There were no significant changes in quality of life except for concerns with the demanding daily infusion schedule. The number of bleeds did not statistically differ from the initial 4 months of the study to the last 8 months. Monthly bleeding rates from the year prior to the study and during the intervention phase were not statistically different. It was also found that daily prophylaxis used 24% less FVIII compared to standard prophylaxis. Taking all of this into account, we have found that providing daily prophylaxis is feasible and that it is feasible to prospectively study daily prophylaxis in youth and young adults.

Background: Acquired hemophilia A (AHA) is a rare disorder with high morbidity and mortality that results from the development of autoantibodies against factor VIII (FVIII). To manage acute bleeding, recombinant porcine FVIII (rpFVIII) can be administered intravenously as a bolus dose of 50IU/kg to 200IU/kg depending on bleeding severity and the level of baseline cross-reacting anti-porcine FVIII inhibitors(Kruse-Jarres et al., 2017). Here we describe the efficacy of rpFVIII used as a continuous infusion (CI) and compare total product utilization to bolus infusions (BI). Methods: Retrospective chart review was conducted on patients with AHA who met the International Society on Thrombosis and Hemostasis criteria for major bleeding and who received rpFVIII at our institution from 2015 to 2020(Kaatz, Ahmad, Spyropoulos, & Schulman, 2015). Efficacy was defined as clinical bleeding control and achievement of adequate FVIII levels. Data were collected through electronic patient records and analyzed using simple descriptive (mean ± standard deviation (SD)) and inferential statistics (T-Test, alpha=0.05). Institutional Research Ethics Board approval was obtained. Results: During the study period, 13 patients received rpFVIII (CI n=3, BI n=10). The mean age of patients receiving CI and BI was 75.3 years (SD 2.5) and 72.0 years (SD 14.5) respectively. All patients who received rpFVIII as a CI received a bolus dose ranging between 102.6IU/kg-200.8IU/kg prior to initiation of the CI. CI rates between 3.4IU/kg/hr-11.5IU/kg/hr were administered. Two of the patients receiving rpFVIII as a CI had their infusion rates adjusted according to their clinical symptoms and FVIII levels. One patient had the rpFVIII CI stopped due to an increase in anti-rpFVIII antibodies which interfered with hemostatic efficacy. Thirty-three percent of CI patients and 60% of BI patients required a red blood cell (RBC) transfusion after starting rpFVIII. Sixty-six percent of CI patients and 20% of BI patients had worsening of bleeding after initiation of rpFVIII. Lastly, rpFVIII usage in the CI group (170.4 ± 25.9 IU/kg/day) was not significantly different compared to the BI group (120.9 ± 64.4 IU/kg/day) when accounting for the duration of admission and weight of the patients (P>0.05). No thromboembolic events occurred in either group while receiving rpFVIII. Conclusions: Our study shows that the total amount of rpFVIII administered to patients as a CI is not significantly different to those receiving BI. The CI group required less RBC transfusions but reported more exacerbation of bleeding. Thus, the efficacy of rpFVIII given as a CI requires further evaluation in future prospective studies. Disclosures Sholzberg: NovoNordisk: Honoraria, Other: Scientific Advisory Board; Novartis: Honoraria, Other: Scientific Advisory Board; Takeda: Honoraria, Other: Scientific Advisory Board, Research Funding; Octapharma: Honoraria, Other: Scientific Advisory Board, Research Funding; Amgen: Honoraria, Other: Scientific Advisory Board, Research Funding. OffLabel Disclosure: Antihemophilic Factor (Recombinant), Porcine Sequence (OBIZUR) is a purified protein produced by recombinant DNA that is a B-domain deleted recombinant factor VIII, porcine sequence, manufactured in tissue culture in baby hamster kidney (BHK) cells. OBIZUR is indicated for the treatment of bleeding episodes in patients with Acquired Hemophilia A (AHA). OBIZUR is administered as a bolus infusion.

Treatment of hemophilia consists of replacement of the missing coagulation factor, either prophylactically or at the time of injury or bleeding. Because of the high cost of these products, which can present a barrier to care, different procurement strategies have been developed at national and regional levels. The emergence of novel therapeutic agents adds complexity to these strategies. This paper examines the benefits and challenges of these strategies, with primary reference to the Canadian context and a consideration of the concepts of value-based care.

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 .).

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 Since there are many disorders that can present with thrombotic microangiopathy (TMA), establishing a correct diagnosis is important to offer the most appropriate therapy. Case Report A 26-year-old woman was transferred to our hospital with fragmentation hemolytic anemia, thrombocytopenia, and acute kidney failure. History revealed that she was recently diagnosed with adult-onset Still's disease (AOSD) and received intraocular injections of bevacizumab to treat acute retinal artery occlusion. At our hospital, she underwent extensive investigations and was treated with high-dose steroids, hemodialysis, and therapeutic plasma exchange. For recurrent disease, she received a single dose of eculizumab. Results The patient's ADAMTS13 activity was normal and she had evidence of complement activation. Genetic testing identified a benign polymorphism in the C3 gene. Pathophysiology of TMA in AOSD is briefly discussed and an overview of the literature is presented. Conclusion Work-up of a new fragmentation hemolytic anemia and thrombocytopenia should include careful review of past history, including medications, as well as relevant laboratory investigations with aim to establish a correct diagnosis. Occasionally, the correct diagnosis is not the obvious one and there could be multiple contributors to the pathogenesis. Establishing diagnosis is important for counseling patient on disease prognosis and to guide treatment.

Introduction: Despite the manifold symptoms that women with inherited bleeding disorders may experience, no study has specifically sought to understand the lived experiences of these women, nor the barriers to care that they may face. Indeed, the literature on this topic remains sparse. A MEDLINE search assessing literature on access to care for women with inherited bleeding disorders yielded 526 abstracts; of these, only a small subset (N=12) focused on women's health, and less (N=2) made any note of potential barriers to care. Given the lack of data on this subject to date, the objective of this qualitative descriptive study was to understand women's lived experiences with inherited bleeding disorders, and their perceptions around access to care. Methods: A semi-structured qualitative interview guide was developed in conjunction with experienced hematologists (MS and RW), patient advocates from the Canadian Hemophilia Society (CHS; PW and DP), and a qualitative research expert (KD). Inclusion criteria for study enrollment included age ≥ 18 years old, English-speaking, and confirmed diagnosis of an inherited bleeding disorder. Women were recruited across Canada through identification by treating healthcare providers and study members of the CHS. They were then consented for telephone interview by SA. Interviews were transcribed verbatim, and analyzed using descriptive thematic analysis on NVIVO software. A random selection of interviews was coded by 2 team members (SA, KD) to ensure similar data interpretation. Results: Ten interviews with women with bleeding disorders were completed. Ages ranged from 24-70, and diagnoses included hemophilia B carriership (N=2), hemophilia A carriership (N=2), von Willebrand disease (N=2), disorders of platelet function (N=3) and dysfibrinogenemia (N=1). Common themes in the data included diagnostic uncertainty, affected family members, bleeding disorders' effect on life, the importance of treatment plans, experienced barriers, and access to care factors (Table 1). The most common barriers to care noted were healthcare provider dismissal of bleeding symptoms, lack of healthcare provider awareness, geographical barriers, and perceived barriers specific to women. Patients noted the importance of as-needed treatment, treatment for abnormal uterine bleeding, iron supplementation, and the need for family planning. They also highlighted the importance of access to clinic and treatment, and the need for self-advocacy. Discussion: To our knowledge, this is the first study to assess lived experiences and barriers to care for women with inherited bleeding disorders. Our data indicates that women often feel dismissed by healthcare providers, and feel disempowered by not feeling understood or heard. These results may have implications for the ways in which healthcare providers communicate with their patients, particularly in the face of diagnostic uncertainty or predominantly gynecologic-related bleeding symptoms. By better understanding patients' lived experiences, providers may be able to provide more comprehensive, person-centered care. Disclosures Teitel: Novo Nordisk: Consultancy; Octapharma: Consultancy; CSL Behring: Consultancy; Pfizer: Consultancy, Research Funding; Bayer: Consultancy, Research Funding; Shire: Consultancy; BioMarin: Consultancy. Sholzberg:Novartis: Honoraria; Amgen: Honoraria, Research Funding.

Inhibitor antibodies to factor VIII arise in a substantial minority of patients with hemophilia A treated with replacement therapy; factor IX inhibitors in treated hemophilia B patients are considerably less common. As replacement therapy is not feasible in most such patients, hemostasis can generally only be achieved with “inhibitor bypassing agents”, namely (activated) prothrombin complex concentrates and recombinant factor VIIa. These agents are widely used to treat active bleeding in inhibitor patients but they have been used relatively infrequently as prophylactic agents to prevent bleeding and its consequences, mainly progressive joint damage. This is in contrast to hemophilia patients without inhibitors, in whom prophylactic replacement with concentrates of factor VIII or IX has become widely accepted as the optimal strategy to prevent these adverse outcomes. This review addresses the current experience and evidence and the future prospects regarding prophylaxis in inhibitor patients.

ObjectiveRecombinant factor VIIa can decrease postoperative bleeding after cardiac surgery. However, the potential for recombinant factor VIIa to cause early vascular graft occlusion at the site of new vascular anastomoses has not been fully explored. We hypothesized that recombinant factor VIIa would cause a dose-dependent reduction in vascular graft patency in rabbits.MethodsReversed end-to-end interpositional vein grafts were sutured into the carotid artery of heparinized rabbits, and then recombinant factor VIIa (300 μg/kg, 90 μg/kg, or 20 μg/kg intravenously) or placebo was administered (n = 16/group). Graft patency was assessed at 24 hours using a vascular ultrasound probe. Factor VII activity levels were measured using a prothrombin time-based assay. In different rabbits, the patency of venous end-to-side anastomoses and simple carotid arterial repairs was assessed (recombinant factor VIIa, 300 μg/kg vs placebo, n = 8/group). Data were analyzed using Fisher’s exact test, t tests, or analysis of variance.ResultsPhysiologic variables (activated clotting time, hemoglobin, pH, Pao2) and vessel diameter were not different between groups. Vein graft patency was reduced (93.8%, 81.2%, 13.8%, and 6.3%) as factor VII activity levels increased (1.8 ± 0.4, 4.4 ± 2.1, 11.8 ± 4.7, and 23.6 ± 16.9 U/mL, respectively) with increasing doses of recombinant factor VIIa administered (0, 20, 90, and 300 μg/kg, respectively, P

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.

In the Bernard-Soulier syndrome (BSS), the giant platelets are said to have increased phosphatidylserine (PS) surface exposure in the resting state and shortened survival in the circulation. When normal platelets are activated, they undergo many biochemical and morphological changes, some of which are apoptotic. Herein, we investigated apoptotic-like events in BSS platelets upon activation, specifically, PS exposure, microparticle (MP) formation, cell shrinkage, and loss of mitochondrial inner membrane potential (DeltaPsi(m)). Platelets from two unrelated BSS patients were examined in whole blood; agonists used were collagen, thrombin, PAR1- or PAR4-activating peptides (APs), or combinations of collagen with thrombin, and the PAR-APs. Flow cytometry was used to measure PS exposure (annexin A5 binding), platelet-derived MPs (forward scatter; events

BACKGROUND: Patients with congenital coagulation disorders and chronic hepatitis C virus (HCV) infection have multiple risk factors (ie, infection predominantly with genotype-1 HCV, long duration of the disease, HIV coinfection and male sex) for poor response to antiviral therapy. The present study compared induction therapy with interferon-alpha (IFN-α)-2b with standard IFN-α2b therapy. Pegylated IFN was not available at the time that the study was initiated.PATIENTS AND METHODS: A randomized study was performed comparing the efficacy of traditional IFN-α2b therapy (group A –three million units, three times weekly for 24 to 48 weeks) and daily ribavirin (1.0 g to 1.2 g according to weight for 24 to 48 weeks), with induction IFN-α2b therapy (group B – three million units, daily for eight weeks followed by the same dose administered three times a week for a further 16 to 40 weeks) and daily ribavirin (same dose as above) in IFN-naive patients with congenital coagulation disorders and chronic HCV infection.RESULTS: Between 2000 and 2003, 54 HIV-negative patients were recruited and randomly assigned to group A or B (n=27 each). Both groups were comparable in terms of age, sex, ethnicity, body mass index, baseline HCV RNA titre, viral genotype, liver fibrosis stage and type of coagulation disorder. Induction therapy did not significantly alter sustained virological response rates (group A 50%, group B 50%; P=1.0). Multiple logistic regression analysis indicated that induction therapy did not benefit individuals with difficult-to-treat infection (ie, those infected with genotypes 1 and 4, or those with high baseline viral loads).CONCLUSIONS: There was no benefit with induction antiviral therapy for HCV infection in individuals with congenital coagulation disorders.

tion by a member of the Society. The Richard Knill competition was instituted in memory of Dr. Richard Knill, a foremost researcher in anesthesiology and prominent collaborator to the Canadian Journal of Anesthesia (CJA). The Annual Meeting Committee selects the top abstracts submitted for presentation by members of the Society at the Annual Meeting. The authors are invited to present their results at the Richard Knill competition. Presentations are marked by a jury composed of the members of the Editorial Board of the CJA. In 2004, the Richard Knill Award was presented to Dr. David C. Campbell for his work on Patient Controlled Epidural Analgesia during labour.

The demonstrated benefits of home care for haemophilia include improved quality of life, less pain and disability, fewer hospitalizations, and less time lost from work or school. Although reduced mortality has not been demonstrated, the substantial increase in longevity since the early 1980s correlates with the introduction of home treatment and prophylaxis programmes. These programmes must be designed and monitored by haemophilia treatment centres (HTC), which are staffed with professionals with broad and complementary expertise in the disease and its complications. In return, patients and their families must be willing to accept the reciprocal responsibilities that come from administering blood products or their recombinant equivalents at home. Patients with inhibitors to factors VIII or IX pose special challenges, but these complications do not obviate participation in home care programmes. Home care was an essential prerequisite to the introduction of effective prophylactic factor replacement therapy. Prophylaxis offers significant improvements in quality of life, but requires a substantial commitment. The use of implantable venous access devices can eliminate some of the difficulty and discomfort of peripheral venous access in small children, but brings additional risks. The future holds the promise of factor concentrates for home use that have longer half-lives, or can be administered by alternate routes. Knowledge of patient genotypes may allow treatments tailored to avoid complications such as inhibitor development. Gene therapy trials, which are currently ongoing, will ultimately lead to gene-based treatments as a complement to traditional protein-based therapy.

To describe a case of persistent and excessive bleeding following an aortic valve and ascending aorta replacement that was successfully managed with recombinant factor VIIa (rFVIIa). The postulated mechanisms for rFVIIa are discussed.A 75-yr-old female with no preoperative coagulopathy underwent a tissue aortic valve replacement and supracoronary ascending aorta replacement for severe aortic stenosis and an ascending aortic aneurysm. Following surgery, she bled in excess of 200 mL x hr(-1) despite a nearly normal platelet count and nearly normal coagulation parameters. The patient was surgically re-explored twice in seven hours, and despite the presence of near normal in vitro coagulation parameters, the patient continued to bleed. Multiple units of fresh frozen plasma, platelets and cryoprecipitate were administered empirically. We then administered a single 6-mg (107 microg x kg(-1)) iv dose of rFVIIa. Following the administration of rFVIIa, blood loss decreased to a total of 440 mL over the next 12 hr.This case describes the use of rFVIIa for intractable bleeding postcardiovascular surgery in the presence of nearly normal laboratory markers of coagulation. Further controlled laboratory and clinical studies are required to define the role of rFVIIa in patients undergoing cardiovascular surgery.

SummaryThe fibrinolytic system is closely related to several processes that are involved in restenosis. We previously showed that low PAI-1 plasma levels predicted restenosis. Recently, a different fibrinolytic inhibitor, TAFI, has been described. The aims of this study were to evaluate the relationship between pre-procedural plasma levels of TAFI and late angiographic restenosis and the interaction between TAFI and PAI-1. We prospectively studied 159 patients with stable angina who underwent successful elective angioplasty or stenting of de novo native coronary artery lesions. TAFI and PAI-1 antigen levels were measured in plasma samples drawn before the procedure. Follow-up coronary angiography was performed in 92% of patients. There was a significant correlation between pre-procedural TAFI levels and 6-month % diameter stenosis (DS) (r = 0.21; p = 0.013). The overall angiographic restenosis rate (DS>50%) was 31%. Pre-procedural TAFI levels were significantly higher in patients with restenosis (108 ± 33% versus 94±30%, p = 0.011). Restenosis rates for patients in the upper tertile of TAFI levels were 2-fold higher than for those in the lowest tertile (45% versus 22%; p = 0.016). A combination of high TAFI and low PAI-1 levels identified patients at the highest risk of restenosis (53%) compared to 14% in patients with low TAFI and high PAI-1 levels; p = 0.027. In conclusion, pre-procedural plasma TAFI antigen levels identify patients at increased risk for restenosis after PCI.

We thank Dr. Giles[1][1] for her interest and commentary on our article.[2][2] For clarification, Drs. Sholzberg, Teitel and Hicks are hematologists, and Dr. Sholzberg is the medical director of the coagulation laboratory at St. Michael’s Hospital. In addition, Drs. Sholzberg and Teitel co-direct

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.

Patients with known coagulation deficiencies, either congenital or acquired, may bleed spontaneously with trauma or with surgical intervention. In contrast, however, are the unchallenged patients who bleed in a variety of clinical settings that demand rapid diagnosis so that appropriate therapy can be instituted. In the first section Dr. Louis M. Aledort demonstrates a series of vignettes of actual cases who presented with unexpected bleeding or a screening laboratory abnormality prior to a needed surgical intervention. Settings include dental, oral surgical, obstetrical, surgical and gynecological. The differential diagnoses of these cases are discussed. In the second section Dr. David Green also uses vignettes to demonstrate how the laboratory is used to differentiate the various clinical entities. The choice and priority of required tests indicated by the settings, history, site and type of bleeding, and the syllogisms used to define the abnormality are stressed. In the third section, Dr. Jerome Teitel reviews in detail the therapeutic armamentarium available to the clinician and presents algorithms for the management of these bleeding disorders.

Six cell lines have been generated from the human fibrosarcoma HT-1080 by mutagenesis. They were selected on the basis of reduced urokinase (uPA) binding on replicate polyester filters. Single cell clones were then isolated by limited dilution cloning. All cloned cells showed less uPA binding on filters, and as cell monolayers. These cell lines were able to bind only 10 to 65% as much uPA as the wild-type HT-1080 cells. Surface-bound uPA proteolytic activity and surface activation of plasminogen from these cells were also reduced relative to the wild-type. uPA could activate MAP kinases in the wild-type and two of the cell lines with the least uPA-binding, but the amount of the activated forms of the signalling molecules were reduced. Immunoblotting using two different anti-uPA receptor antibodies showed two cross-reacting protein species of ∼ 53 kDa and ∼ 38 kDa. The proportion of the lower Mr band to the higher Mr band was found to be reduced in all the cell lines relative to the wild-type. Chemical cross-linking with single-chain urokinase (scuPA) showed only one high-molecular-weight adduct, with Mr∼90 kDa, in all the cell lines tested. Similarly, cross-linking with the amino terminal fragment of uPA yielded a single ∼70 kDa adduct. These would indicate that only the ∼53 kDa band was responsible for cross-linking reactions. Equilibrium binding experiments showed that only one set of high-affinity binding sites for the wild-type cells. However, the binding of scuPA to two of these cell lines was best fitted to a two-site model, one of which was similar to the high-affinity binding sites of the wild-type, although the number of sites was reduced, while the other was of much lower affinity but was large in number. These results are discussed in relation to changes in the structure of ligand binding machinery in these cells, which affect other cellular functions.

We studied the effects of porcine factor VIII (P-FVIII; Hyate:C) and other coagulation products employed in the management of patients with hemophilia A, on platelet activation in vitro. Exposure of normal resting platelets to P-FVIII resulted in platelet activation, as manifested by increased expression of the platelet surface activation markers CD62, CD63, and activated-GPIIbIIIa, and by activation-induced modulation of expression of normal platelet membrane glycoproteins CD41, CD42, and CD36. In contrast, platelet activation was not observed after exposure of the platelets to human FVIII, FEIBA, recombinant FVIIa, or cryosupernatant plasma. As with thrombin, exposure of platelets to P-FVIII resulted in the generation of platelet microparticles, an effect not seen not with the other products. In contrast to the characteristic reduction in expression in the number of CD42 molecules detected on thrombin-activated platelets, P-FVIII-stimulated platelets showed a small increase in CD42 expression. In contrast to thrombin, P-FVIII did not cause platelet dense granule release. The results indicate that therapeutic P-FVIII activates platelets, likely in ways that are different from the platelet activation seen with thrombin. The observed platelet activation and microparticle generation may provide a "hypercoagulable" mechanism for hemostasis with P-FVIII therapy separate from, and additional to, that due to increased circulating FVIII levels.

SummaryA multicentre retrospective survey was conducted to re-assess the use of porcine factor VIII (HYATE:C), its side effects and the selection of patients for regular or home-therapy. 15,152,000 units of HYATE:C were used by 154 patients. The median inhibitor cross-reactivity to porcine VIIIC of 137 patients was 15%, 27% of patients lacking cross-reactivity. An absent, intermediate or brisk specific antiporcine anamnestic response was observed in 29, 40 and 31% of patients respectively. Seven patients were treated on-demand as home-therapy for a median 6.2, range 1.5-13 years. 23 further patients were treated regularly in hospital for a median of 3, range 2-7 years. This group used 8,319,000 U of porcine VIIIC for 2,000 bleeding episodes.The incidence of transfusion reactions was 0.001%, 0.64% and 2.3%, for domiciliary infusions, infusions in multiply treated inpatients, and unselected in-patient infusions, respectively. The risk of reactions was dose-related. A post-infusion fall in platelet count was common, but usually transient and clinically insignificant. This was also dose-related (r = -0.64, p = 0.002). Marked reductions in platelet count were occasionally seen, usually with intensive replacement therapy. The relative lack of side effects observed amongst patients treated at home is attributable to the low, median 33 U/kg, dose used by this group.A subgroup of inhibitor patients, identifiable by their absent or modest anamnestic response to porcine factor VIII may be treated regularly and safely with this product in small doses, over a period of years.

A 74-year mild hemophiliac with an inhibitor to factor VIII underwent five 2-L plasma immunoadsorption procedures with a Staphylococcal protein A (Prosorba) column over 7 days. Initially, the inhibitor level increased from 56 to 154 BU/mL. Serum immunoglobulins, immune complexes, C3 and C4 fell progressively with each procedure: C3a was increased. Before therapy, the patient had increased cytotoxic T and activated T cells which decreased to the normal range with treatment. The proportion of T inducer cell and CD4:CD3 ratios increased progressively with each treatment. Natural killer cell activity remained unchanged. Unstimulated patient lymphocytes showed high proliferative activity, but after therapy there was markedly reduced response to mitogens. Both patient and normal lymphocytes showed marked increase in thymidine incorporation when incubated with adsorbed plasma (from column outlet), compared to incubation with unadsorbed plasma (column inlet). The patient's serum showed a progressive rise in this “mitogenicity” effect, maximal after the third procedure, then declining to pre-treatment levels after the fifth procedure. After the third immunoadsorption, inhibitor level was 70 BU/mL and he was given prednisone and cyclophosphamide; after the fifth procedure it was 32 BU/mL and 6 months later was undetectable. Although subsequent decrease in the inhibitor may have been due to the plasma immunoadsorption, it is important to note that this treatment may be paradoxically associated with a rise in antibody levels. In addition to antibody changes, Staph. protein A perfusion affected cellular immunity.

We, the 8 coauthors of this letter and the 59 Canadian physicians and scientists who have reviewed and endorsed it, are writing in response to 2 articles in the Mar. 17, 2009, issue of CMAJ : “Gaza’s health care system crippled before — and after” by Christopher Mason and “On the ground in

SummaryAn experimental model incorporating cultured endothelial cells (EC) was used to study the "factor VIII bypassing" activity of prothrombin complex concentrates (PCC), a property exploited in the treatment of hemophiliacs with alloantibodies to factor VIII. Two PCC preparations were ineffective as stimuli of tissue factor expression by EC. However, incubation with a combination of PCC plus endotoxin (lipopolysaccharide, LPS) or tumor necrosis factor (TNF) induced much greater tissue factor expression than was seen in response to either substance alone. PCC expressed an additional direct procoagulant activity at the EC surface, which could not be attributed to either thrombin or factor Xa, and which was diminished by an anti-tissue factor antibody. Therefore factor VIIa, which was detectable in both PCC preparations, likely provided this additional direct procoagulant activity at the EC surface. We also excluded the possibility that coagulation proteases contained in or generated in the presence of PCC are protected from inactivation by AT III. Therefore, PCC can indirectly bypass factor VIII by enhancing induced endothelial tissue factor expression, and also possess direct procoagulant activity, probably mediated by factor VIIa.

All but essential surgery is generally avoided in haemophilia patients with inhibitor antibodies, because of concern about the reliability with which haemostasis can be achieved and maintained in such patients. Orthopaedic surgical procedures which are not required to preserve life fall under this category. As a result, patients with inhibitors may be denied operations, which could greatly enhance their quality of life, and which are routinely offered to other haemophilia patients. While caution is appropriate in recommending surgery in any circumstance, we believe that the threshold for offering validated surgical procedures to patients with inhibitors should be re-evaluated in the light of current surgical and rehabilitative techniques, and the long experience with safe and effective factor VIII inhibitor bypassing agents, namely activated prothrombin complex concentrates and recombinant activated factor FVII. In this article, we review the haematological, surgical and rehabilitative considerations relevant to orthopaedic surgery in haemophilia patients with inhibitors, and provide recommendations for carrying out such procedures.

Two bypassing agents are currently available to circumvent the need for factor FVIII in hemophilia A patients with inhibitors: the activated prothrombin complex FEIBA VH and recombinant activated factor VII (NovoSeven®). Both products are highly effective in controlling bleeding in the presence of inhibitory alloantibodies, yet their hemostatic efficacy can be unpredictable. As the results of the FEIBA NovoSeven® Comparative (FENOC) study illustrate, patients may respond better to one bypassing agent than the other. Furthermore, guidelines from an expert panel reflect that responsiveness to bypassing therapy may change from one bleed to the next in the same patient and even from hour to hour during the course of a single bleeding event. These findings underscore the need to have both bypassing products available to treat bleeding episodes in inhibitor patients, to frequently evaluate the efficacy of hemostasis during the course of a bleeding event, and to switch products early if the response to treatment is unsatisfactory. © 2008 Elsevier Ltd. All rights reserved.

The introduction of new factor concentrates has, at times, resulted in an increase in inhibitor development; hence large systematic surveys of inhibitor development are necessary whenever new products are introduced. This study presents the results of a surveillance study conducted by the Inhibitor Subcommittee of the Association of Hemophilia Clinic Directors of Canada that evaluated inhibitor development in patients with haemophilia A following the switch to a second generation recombinant FVIII product (rFVIII-FS; Kogenate((R)) Bayer). Four hundred and sixty haemophilia A paediatric and adults patients from 17 Canadian Comprehensive Hemophilia Care Centers were enrolled in the study. Of these, 274 patients had evaluable data. Blood samples collected at baseline (prior to the switch to rFVIII-FS), and at 12 and 24 months following conversion were tested for inhibitors by the Nijmegen-modified Bethesda assay. Four subjects had positive inhibitor titres at baseline, with values ranging from 3.3 to 160 BU. Of the 274 patients who had baseline samples collected, 225 had postswitch samples collected at 12 months and 189 subjects had samples collected at 24 months. Only patients with positive baseline inhibitor titres (n = 4) had positive inhibitor titres at either the 12- or 24-month postswitch time points; therefore no de novo inhibitors developed over the 2-year evaluation period in this patient population. The results of this surveillance study suggest that the altered formulation of this recombinant FVIII concentrate was not associated with an increased incidence of inhibitor formation.

The effects of live endothelial cells (EC), paraformaldehyde fixed EC, and EC supernatant were measured on pokeweed mitogen (PWM)-induced T-cell-dependent plaque-forming cell (PFC) generation by peripheral blood mononuclear cell (PBM). At low doses (≤ 2 × 104 cells/culture) live EC helped PFC generation. At higher doses (≥ 10 × 104 cells/culture) the effect of live EC was always marked suppression (< 10% of baseline PFC). In contrast both fixed EC and EC supernatant provided help exclusively over a wide dose range. The EC-helper effect enhanced the sensitivity of PBM to suboptimal PWM doses and also accelerated the rate of PFC generation during culture. EC influences on PFC could not be modified by gamma-interferon induction of surface DR which is known to modify EC accessory cell ability. There was also only minimal helper activity of live EC and fixed EC on the PFC generation by Epstein-Barr virus-induced cultures of purified B cells (which had been depleted of both T cells and monocytes). In contrast, suppression (> 97%) of PFC in isolated B-cell cultures was found even when EC constituted < 1 % of cultured cells. These results imply EC have the potential of providing multiple regulatory signals which modulate in vitro antibody production. EC-derived mechanisms are independent of their accessory cell function and require interaction with non-B cells for help, but suppression may occur directly at the B-cell level. EC are thus not only capable of providing an accessory cell signal which can initiate immune responses, they also may profoundly influence on-going immune processes initiated by other immunocytes.

In this paper, we report an inhibitor antibody to factor XI (FXI) in a woman with severe inherited FXI deficiency, induced by FXI present in an Rh immune globulin preparation. The patient is homozygous for the Glu117Stop mutation, associated with a FXI level of less than 1 U/dL. Unlike all previously described patients with severe FXI deficiency and an inhibitor, the patient had never been exposed to blood products. Following 3 injections of Rh immune globulin during pregnancy, she developed an inhibitor to FXI (8 Bethesda units) that was shown to bind specifically to FXI and inhibit factor IX cleavage by purified FXIa. The administered Rh immune globulin and 2 other similar products were shown to contain FXI. Clinicians should be aware of the potential for immunization of severely FXI-deficient patients by FXI present in Rh immune globulin preparations.

Background: Atypical HUS is a rare disorder caused by uncontrolled activation of the alternative pathway of complement. It presents with thrombotic microangiopathy (TMA), renal insufficiency and in 20% of cases extrarenal manifestations. Most cases of aHUS result from a genetic defect. Methods: We conducted a retrospective chart review of all adult patients with TMA assessed by our apheresis service between January 1, 2010 and December 31, 2013. Complement genetics studies included screening CFI, CFH, CFB, MCP/CD46, CFHR5, C3 and THBD/CD141 genes and were performed at The Hospital for Sick Children, Toronto, Canada. Complement protein and function studies (CH50, AH50, C3d, sC5b-9, C3, factor H, factor I, and anti-CFH antibody) were performed at the University of Heidelberg, Germany. Results: During the study period, 65 patients with TMA were assessed. On clinical and laboratory grounds, 16 patients (25%) were diagnosed with aHUS. 15 patients underwent complement genetics studies and 10/15 (73%) had no disease causing mutations identified. Data on 5 patients with genetic abnormalities are summarized in Table 1. All patients were women, mean age 33 years. 4 patients (80%) had extra-renal manifestations. Mean PLT count nadir during acute episode was 40xE9/L. In most TMA episodes, therapeutic plasma exchange (TPE) resulted in a partial response (normalization/stabilization of thrombocytopenia and/or LD and/or creatinine) (Table 1). Due to limited access to eculizumab, the drug was not consistently used. 3 patients (2, 3 and 5) had low C3 and normal C4, a pattern classically described in aHUS. 4 patients underwent additional complement protein studies during acute episode (Table 2). Abstract 4186. Table 1. Age, sex Mutation TMA episodes Renal manifestations Extrarenalmanifestations Other medical conditions Treatment of TMA episode and outcome 1 20 F polymorphism vs. disease-causing mutation in CFH gene, c.3148A>T (p.Asn1050Tyr) 1st and only episode Peak Cr 104 Retinal hemorrhages, headache, hypertensive emergency, abdominal pain, elevated liver enzymes Dyskeratosis congenita, alloBMT Partial response to TPEResponse to eculizumabDied of sepsis 2 43 F unknown mutation in CFHR5 gene, c.1412G>A (p.Gly471Glu) 1st episode ESRD, dialysisLiving related kidney transplant 8 yrs post 1st episode Cardiomyopathy, mitral regurgitation Crohn's disase Partial response to TPENo renal recovery 2nd episode TMA recurrence in graft, ESRD, dialysis Pulmonary hemorrhage Partial response to TPE, steroids, eculizumab (single dose)No renal recoveryMost recent follow-up: TMA free, on dialysis, awaiting 2nd transplant 3 29 F variant of unknown significance in C3 gene, c.1685C>T (p.Ser562Leu) predicted to be benign 1st and only episode Cr 650, Required hemodialysis Central retinal artery occlusion, abdominal pain, effusions, seizures, hypertensive emergency Adult Onset Still's Disease Partial response to TPEPartial response to Eculizumab (single dose) Most recent follow-up: TMA free, Cr 95 4 33 F disease-causing mutation in CFHR5 gene, c.1135G>C (p.Val379Leu) 1st episode Not available Hypertensive emergency Pulmonary embolus, cardiac arrest Blood pressure control, improved 2nd episode Peak Cr 345 Hypertensive emergency, headache, small bowel ischemia, pancreatitis, effusions Partial response to TPE Most recent follow-up: TMA free, Cr 89 5 42 F disease-causing mutation in CFI gene, c.949C>T (p.Arg317Trp) and variant of unknown significance in C3 gene (c.193A>C p.Lys65Gln) 1st episode Peak Cr 200 Hypertension Hypo-thyroidism Complete response to TPE, steroids 2nd episode Peak Cr 700, dialysis not required Complete response to TPE, steroids 3rd episode Peak Cr unknown, Dialysis required Complete response to TPE, steroids 4th episode Peak Cr 533 Partial response to TPE, steroidsHematologic response to Rituximab, splenectomyTMA free, Cr 175Started on eculizumab 1 year agoMost recent follow-up: TMA free, Cr 117 Table 2. Case Complement protein and function studies 1 No abnormalities 2 Elevated AH50, sC5b-9Low C3, fH 3 Elevated sC5b-9Low C3 4 Elevated AH50 5 Not done Conclusions: 33% of patients diagnosed with aHUS had abnormalities detected on genetic studies. Extrarenal manifestations were common and, in most cases, TPE resulted in only a partial response. Only 3 patients had a classically described pattern of low C3 and normal C4. The utility of extensive complement protein studies requires further study. Disclosures Pavenski: Alexion Pharmaceuticals: Honoraria. Licht:Alexion Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau.

Prior to the introduction of virally inactivated clotting factor concentrates, the majority of individuals with congenital bleeding disorders became infected with the hepatitis C virus. Although liver biopsy is valuable in prognosis and guiding antiviral therapy, there is a reluctance to perform biopsies in this population because of the risk of hemorrhage. The purpose of this study was to evaluate the safety of transjugular liver biopsy, and the usefulness of evaluating liver histology in this patient population. Liver histopathology was assessed by the METAVIR index and compared with corrected sinusoidal pressures, platelet counts, and abdominal ultrasonography. Liver biopsy was performed at seven Canadian centers in 65 patients with hemophilia or von Willebrand's disease. Biopsies were done on an outpatient basis, followed by a 4-hr observation period in hospital. Normal hemostasis was maintained during the peribiopsy period, with follow-up doses of factor concentrate self administered by the patient at home. One patient (1.4%) had significant bleeding leading to readmission and red cell transfusion. Liver histology showed 14 patients (22%) had cirrhosis. Ten patients had elevated corrected sinusoidal pressures; 7 of these (70%) had cirrhosis on biopsy, and the other 3 (30%) likely had cirrhosis although histology showed stage 3 fibrosis. This series represents the largest reported experience of transjugular biopsy in individuals with congenital bleeding disorders. We conclude that this procedure can be safely performed on an outpatient basis. The diagnosis of cirrhosis and/or portal hypertension was made in a substantial proportion of individuals (26%), all of whom had asymptomatic liver disease.