The Pitfalls of Global Hemostasis Assays in Myeloproliferative Neoplasms and Future Challenges.

Venous and arterial thromboembolism are major complications of myeloproliferative neoplasms (MPNs), comprising polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). Global hemostasis assays, including thrombin generation assay (TGA), rotational thromboelastometry (ROTEM), and thromboelastography (TEG), have been proposed as biomarkers to assess the hypercoagulability and thrombotic risk stratification in MPNs. We performed a systematic literature review on the parameters of TGA, ROTEM, and TEG and their association with thrombotic events and treatment strategies in MPNs. Thirty-two studies (all cross-sectional) were included, which collectively enrolled 1,062 controls and 1,608 MPN patients. Among the 13 studies that reported arterial or venous thrombosis, the overall thrombosis rate was 13.8% with 6 splanchnic thromboses reported. Out of the 27 TGA studies, there was substantial heterogeneity in plasma preparation and trigger reagents employed in laboratory assays. There was a trend toward increased peak height among all MPN cohorts versus controls and higher endogenous thrombin potential (ETP) between ET patients versus controls. There was an overall trend toward lower ETP between PV and PMF patients versus. controls. There were no substantial differences in ETP between JAK2-positive versus JAK2-negative MPNs, prior history versus negative history of thrombotic events, and among different treatment strategies. Of the three ROTEM studies, there was a trend toward higher maximum clot firmness and shorter clot formation times for all MPNs versus controls. The three TEG studies had mixed results. We conclude that the ability of parameters from global hemostasis assays to predict for hypercoagulability events in MPN patients is inconsistent and inconclusive. Further prospective longitudinal studies are needed to validate these biomarker tools so that thrombotic potential could be utilized as a primary endpoint of such studies.

SARS-CoV-2 vaccination and ITP in patients with de novo or preexisting ITP.

Cases of de novo immune thrombocytopenia (ITP), including a fatality, following SARS-CoV-2 vaccination in previously healthy recipients led to studying its impact in preexisting ITP. In this study, 4 data sources were analyzed: the Vaccine Adverse Events Reporting System (VAERS) for cases of de novo ITP; a 10-center retrospective study of adults with preexisting ITP receiving SARS-CoV-2 vaccination; and surveys distributed by the Platelet Disorder Support Association (PDSA) and the United Kingdom (UK) ITP Support Association. Seventy-seven de novo ITP cases were identified in VAERS, presenting with median platelet count of 3 [1-9] ×109/L approximately 1 week postvaccination. Of 28 patients with available data, 26 responded to treatment with corticosteroids and/or intravenous immunoglobulin (IVIG), and/or platelet transfusions. Among 117 patients with preexisting ITP who received a SARS-CoV-2 vaccine, 19 experienced an ITP exacerbation (any of: ≥50% decline in platelet count, nadir platelet count <30 × 109/L with >20% decrease from baseline, and/or use of rescue therapy) following the first dose and 14 of 70 after a second dose. Splenectomized persons and those who received 5 or more prior lines of therapy were at highest risk of ITP exacerbation. Fifteen patients received and responded to rescue treatment. In surveys of both 57 PDSA and 43 UK patients with ITP, prior splenectomy was associated with worsened thrombocytopenia. ITP may worsen in preexisting ITP or be identified de novo post-SARS-CoV2 vaccination; both situations responded well to treatment. Proactive monitoring of patients with known ITP, especially those postsplenectomy and with more refractory disease, is indicated.

A randomized phase 3 trial of interferon-α vs hydroxyurea in polycythemia vera and essential thrombocythemia.

The goal of therapy for patients with essential thrombocythemia (ET) and polycythemia vera (PV) is to reduce thrombotic events by normalizing blood counts. Hydroxyurea (HU) and interferon-α (IFN-α) are the most frequently used cytoreductive options for patients with ET and PV at high risk for vascular complications. Myeloproliferative Disorders Research Consortium 112 was an investigator-initiated, phase 3 trial comparing HU to pegylated IFN-α (PEG) in treatment-naïve, high-risk patients with ET/PV. The primary endpoint was complete response (CR) rate at 12 months. A total of 168 patients were treated for a median of 81.0 weeks. CR for HU was 37% and 35% for PEG (P = .80) at 12 months. At 24 to 36 months, CR was 20% to 17% for HU and 29% to 33% for PEG. PEG led to a greater reduction in JAK2V617F at 24 months, but histopathologic responses were more frequent with HU. Thrombotic events and disease progression were infrequent in both arms, whereas grade 3/4 adverse events were more frequent with PEG (46% vs 28%). At 12 months of treatment, there was no significant difference in CR rates between HU and PEG. This study indicates that PEG and HU are both effective treatments for PV and ET. With longer treatment, PEG was more effective in normalizing blood counts and reducing driver mutation burden, whereas HU produced more histopathologic responses. Despite these differences, both agents did not differ in limiting thrombotic events and disease progression in high-risk patients with ET/PV. This trial was registered at www.clinicaltrials.gov as #NCT01259856.

Association of patient, treatment and disease characteristics with patient-reported outcomes: Results of the ECHO Registry.

INTRODUCTION: Patient-reported outcomes (PROs) in people living with haemophilia A (PLWHA) are often under-reported. Investigating PROs from a single study with a diverse population of PLWHA is valuable, irrespective of FVIII product or regimen. AIM: To report available data from the Expanding Communications on Haemophilia A Outcomes (ECHO) registry investigating the associations of patient, treatment and disease characteristics with PROs and clinical outcomes in PLWHA. METHODS: ECHO (NCT02396862), a prospective, multinational, observational registry, enrolled participants aged ≥16 years with moderate or severe haemophilia A using any product or treatment regimen. Data collection, including a variety of PRO questionnaires, was planned at baseline and annually for ≥2 years. Associations between PRO scores and patient, treatment and disease characteristics were determined by statistical analyses. RESULTS: ECHO was terminated early owing to logistical constraints. Baseline data were available from 269 PLWHA from Europe, the United States and Japan. Most participants received prophylactic treatment (76.2%), with those using extended-half-life products (10.0%) reporting higher treatment satisfaction. Older age and body weight >30 kg/m2 (>BMI) were associated with poorer joint health. Older age was associated with poorer physical functioning and work productivity. Health-related quality of life and pain interference also deteriorated with age and >BMI; >BMI also increased pain severity scores. CONCLUSION: ECHO captured a variety of disease characteristics, treatment patterns, PROs and clinical outcomes obtained in real-world practice with ≤1 year's follow-up. Older age, poorer joint health and >BMI adversely affected multiple aspects of participant well-being.

A novel gene editing lexicon strategy for the haemophilia community: Research plan for development and preliminary results.

INTRODUCTION: Despite the progress in gene editing platforms like CRISPR/Cas9 with the potential to transform the standard of care for haemophilia, the language used to explain and discuss gene editing is not aligned across the haemophilia community. Here, we present the objective and rationale for developing a clear, consistent, and globally aligned gene editing lexicon to address these communication gaps. METHODS: Effectively communicating complex gene editing concepts requires a clear and consistent vocabulary. Through collaboration with a diversity of haemophilia stakeholders, our main goal is to develop an accurate, informative lexicon which avoids overpromising or highly technical terminology. Using an innovative process, representatives from several patient and scientific haemophilia organizations and select biotechnology companies will develop and refine language concepts to be tested with approximately seventy participants across the United States of America, United Kingdom, and Germany. Participants will include lived experience experts (LEEs) and haematologists. The process will be overseen by the Lexicon Steering Committee of global experts from leading scientific and patient organizations in the haemophilia and gene editing fields. RESULTS: Initial feedback provided a robust foundation and rationale for building clear, consistent language around gene editing. This lexicon development framework will allow for increased understanding across the haemophilia community, including the development of valid informed consent and shared decision-making materials. CONCLUSION: Results provide important building blocks for stimuli development and highlight the need for a novel gene editing lexicon. In the next phase, language stimuli will be tested with LEEs and haematologists to better understand audience preferences and help shape the final lexicon.

Risk of myeloproliferative neoplasms among U.S. Veterans from Korean, Vietnam, and Persian Gulf War eras.

The Promise to Address Comprehensive Toxics (PACT) Act expanded U.S. Veterans' health care and benefits for conditions linked to service-connected exposures (e.g., Burn Pits, Agent Orange). However, myeloproliferative neoplasms (MPN) are not recognized as presumptive conditions for Veterans exposed to these toxic substances. This study evaluated the development of MPN among U.S. Veterans from the Korean, Vietnam, and Persian Gulf War eras. This retrospective cohort study included 65 425 Korean War era Veterans; 211 927 Vietnam War era Veterans; and 214 007 Persian Gulf War era Veterans from January 1, 2006, to January 26, 2023. Veterans with MPN, thrombosis, bleeding, and cardiovascular risk factors were identified through ICD-9 and -10 codes. Veterans from the Persian Gulf War era had the highest risk of developing MPN compared with Veterans from the Korean and Vietnam War eras, hazard ratio (HR) 4.92, 95% confidence interval (CI) 4.20-5.75 and HR 2.49, 95% CI 2.20-2.82, both p < .0001, respectively. Vietnam War era Veterans also had a higher risk of MPN development compared with Korean War era Veterans, HR 1.97, 95% CI 1.77-2.21, p < .0001. Persian Gulf War era Veterans were diagnosed with MPN at an earlier age, had higher risks of thrombosis and bleeding, and had lower survival rates compared with Korean War and Vietnam War era Veterans. This study reinforces evidence that environmental and occupational hazards increase the risk of clonal myeloid disorders and related complications, impacting overall survival with MPN. Limitations include the inability to confirm clonality and fully verify deployment and exposure status.

PFA-100 System: A New Method for Assessment of Platelet Dysfunction.

This is a celebratory reprint of a historical paper published in STH in 1998. The original Abstract follows.The PFA-100 system is a platelet function analyzer designed to measure platelet-related primary hemostasis. The instrument uses two disposable cartridges: a collagen/epinephrine (CEPI) and a collagen/ADP (CADP) cartridge. Previous experience has shown that CEPI cartridges detect qualitative platelet defects, including acetylsalicylic acid (ASA)-induced abnormalities, while CADP cartridges detect only thrombocytopathies and not ASA use. In this seven-center trial, 206 healthy subjects and 176 persons with various platelet-related defects, including 127 ASA users, were studied. The platelet function status was determined by a platelet function test panel. Comparisons were made as to how well the defects were identified by the PFA-100 system and by platelet aggregometry. The reference intervals for both cartridges, testing the 206 healthy subjects, were similar to values described in smaller studies in the literature (mean closure time [CT] of 132 seconds for CEPI and 93 seconds for CADP). The use of different lot numbers of cartridges or duplicate versus singleton testing revealed no differences. Compared with the platelet function status, the PFA-100 system had a clinical sensitivity of 94.9% and a specificity of 88.8%. For aggregometry, a sensitivity of 94.3% and a specificity of 88.3% were obtained. These values are based on all 382 specimens. A separate analysis of sensitivity by type of platelet defect, ASA use versus congenital thrombocytopathies, revealed for the PFA-100 system a 94.5% sensitivity in identifying ASA users and a 95.9% sensitivity in identifying the other defects. For aggregometry, the values were 100% for ASA users and 79.6% for congenital defects. Analysis of concordance between the PFA-100 system and aggregometry revealed no difference in clinical sensitivity and specificity between the systems (p > 0.9999). The overall agreement was 87.5%, with a Kappa index of 0.751. The two tests are thus equivalent in their ability to identify normal and abnormal platelet defects. Testing 126 subjects who took 325 mg ASA revealed that the PFA-100 system (CEPI) was able to detect 71.7% of ASA-induced defects with a positive predictive value of 97.8%. The overall clinical accuracy of the system, calculated from the area under the receiver operating characteristic curve, was 0.977. The data suggest that the PFA-100 system is highly accurate in discriminating normal from abnormal platelet function. The ease of operation of the instrument makes it a useful tool to use in screening patients for platelet-related hemostasis defects.

Emicizumab: the hemophilia A game changer.

In hemophilia, the unmet needs regarding adherence to prophylaxis and lack of effective longterm prophylaxis regimens, especially in patients with inhibitors, led to the production of emicizumab, the first non-factor medicine for subcutaneous administration in patients with severe and moderate hemophilia A with or without factor VIII inhibitors. This article describes the research steps behind the development of this game-changer medication, its success for the prophylaxis of bleeding episodes as witnessed by the results of pivotal clinical trial but also by real life use in the frame of a still expanding global market. We shall also discuss potential and actual adverse events and the nuances related to clinical use such as laboratory monitoring, development of neutralizing anti-drug-antibodies, risk of thrombosis/hypercoagulability and use in the management of surgical operations. The potential of using emicizumab to prevent bleeding in other congenital and acquired coagulation disorders will also be sketched.

Bleeding events in people with congenital haemophilia A without factor VIII inhibitors receiving prophylactic factor VIII treatment: A systematic literature review.

BACKGROUND: Evidence on bleeding rates in people with congenital haemophilia A (PwcHA) without inhibitors on factor VIII (FVIII) replacement products is inconsistent. AIM: This systematic literature review assessed bleeding outcomes in PwcHA using FVIII-containing products as prophylactic treatment. METHODS: A search was conducted using the bibliographic databases Medline, Embase and Cochrane Central Register of Controlled Trials on the Ovid platform. The search involved a bibliographic review of clinical trial studies, routine clinical care studies and registries and a search of ClinicalTrials.gov, EU Clinical Trials Register and conference abstracts. RESULTS: The search yielded 5548 citations. A total of 58 publications were included for analysis. In 48 interventional studies, the pooled estimated mean (95% confidence interval [CI]) annualized bleeding rate (ABR), annualized joint bleeding rate (AJBR) and proportion of participants with zero bleeding events were 3.4 (3.0-3.7), 2.0 (1.6-2.5), and 38.5% (33.1-43.9), respectively. In 10 observational studies, the pooled estimated mean (95% CI) ABR, AJBR and proportion of participants with zero bleeding events were 4.8 (4.0-5.5), 2.6 (2.1-3.2), and 21.8% (19.9-47.5), respectively. A large variation in mean effect size for ABR, AJBR and zero bleeding event data across cohorts and cohort types was observed. Funnel plots indicated potential reporting bias for publications incorporating ABR and AJBR data across both interventional and observational studies. CONCLUSION: This meta-analysis shows that PwcHA without inhibitors still have bleeds despite FVIII prophylaxis. Improved standardization on capturing and reporting bleeding outcomes is needed so that effective comparisons between treatments can be made.

Clinical efficacy of simoctocog alfa versus extended half-life recombinant FVIII concentrates in hemophilia A patients undergoing personalized prophylaxis using a matching-adjusted indirect comparison method.

OBJECTIVES: We aimed to indirectly compare the efficacy of personalized prophylaxis with simoctocog alfa (Nuwiq®) versus three extended half-life (EHL) recombinant FVIII (rFVIII) concentrates. METHODS: Treatment effects were compared using matching-adjusted indirect comparisons after matching individual patient-level baseline characteristics for simoctocog alfa (pharmacokinetic [PK]-guided personalized prophylaxis) against published aggregate personalized prophylaxis data for efmoroctocog alfa, damoctocog alfa pegol, and rurioctocog alfa pegol. RESULTS: A higher percentage (p < .001) of patients with zero bleeds was found with simoctocog alfa compared with efmoroctocog alfa (75% vs. 45%), damoctocog alfa pegol (77% vs. 38%), and rurioctocog alfa pegol (target trough level 1%-3%; 78% vs. 42%). Similar efficacy was found comparing simoctocog alfa against rurioctocog alfa pegol 8%-12% (77% vs. 62%). The mean total annualized bleeding rate was lower (p < .001) with simoctocog alfa than damoctocog alfa pegol (1.5 vs. 4.9). Consistent with approved dosing, the mean FVIII weekly dose was higher (p < .001) for simoctocog alfa than efmoroctocog alfa, damoctocog alfa pegol, or rurioctocog alfa pegol 1%-3%, but lower (p < .001) than rurioctocog alfa pegol 8%-12%. CONCLUSIONS: Indirect comparisons demonstrated that PK-guided, personalized prophylaxis with simoctocog alfa can lead to higher zero bleed rates compared with personalized EHL rFVIII concentrate regimens, albeit with higher weekly doses, and a lower percentage of patients treated twice weekly or less.

First-in-human in vivo genome editing via AAV-zinc-finger nucleases for mucopolysaccharidosis I/II and hemophilia B.

Zinc-finger nuclease (ZFN)-based in vivo genome editing is a novel treatment that can potentially provide lifelong protein replacement with single intravenous administration. Three first-in-human open-label ascending single-dose phase 1/2 studies were performed in parallel (starting November 2017) primarily to assess safety and tolerability of ZFN in vivo editing therapy in mucopolysaccharidosis I (MPS I) (n = 3), MPS II (n = 9), and hemophilia B (n = 1). Treatment was well tolerated with no serious treatment-related adverse events. At the 1e13 vg/kg dose, evidence of genome editing was detected through albumin-transgene fusion transcripts in liver for MPS II (n = 2) and MPS I (n = 1) subjects. The MPS I subject also had a transient increase in leukocyte iduronidase activity to the lower normal range. At the 5e13 vg/kg dose, one MPS II subject had a transient increase in plasma iduronate-2-sulfatase approaching normal levels and one MPS I subject approached mid-normal levels of leukocyte iduronidase activity with no evidence of genome editing. The hemophilia B subject was not able to decrease use of factor IX concentrate; genome editing could not be assessed. Overall, ZFN in vivo editing therapy had a favorable safety profile with evidence of targeted genome editing in liver, but no long-term enzyme expression in blood.

Recent advances in understanding spleen tyrosine kinase (SYK) in human biology and disease, with a focus on fostamatinib.

Spleen tyrosine kinase (SYK) is an important regulatory molecule of signal transduction pathways involved in the pathogenesis of autoimmune diseases such as immune thrombocytopenia (ITP), and the SYK-signaling pathway has emerged as a potential target for the treatment of numerous diseases. The aim of this narrative review is to summarize the biological properties of SYK and its involvement in disease pathways, provide an update on SYK inhibitors in the treatment of ITP, and consider other potential applications. Fostamatinib, the only licensed SYK inhibitor to date, produces clinical response in ITP patients, including those who are refractory to other treatments. It appears to reduce the risk of thrombotic events and may therefore be a drug to consider for patients with an increased thrombotic risk. Encouraging results have also been obtained in the treatment of warm autoimmune hemolytic anemia. Several other SYK inhibitors have entered clinical trials for a range of indications, reflecting the ability of these drugs to affect multiple signaling pathways. SYK inhibitors have the potential to target several aspects of COVID-19 pathogenesis including thrombosis, without affecting normal hemostasis, and data from the first study of fostamatinib in COVID-19 are encouraging. It is hoped that ongoing trials in autoimmune indications other than ITP, as well as in hematological malignancies and other disorders, confirm the promise of SYK inhibitors.

Immune thrombocytopenia (ITP) is an autoimmune disease that usually happens when your immune system mistakenly attacks and destroys platelets, which are cells that help blood to clot. Individuals with ITP can experience easy or excessive bruising and bleeding. Scientists have identified that an enzyme called spleen tyrosine kinase (SYK) is involved in numerous biological processes that are associated with the immune system response, inflammation, and some types of cancer in humans. Therefore, it has become a target for new drugs which inhibit the action of SYK. In this review article, the authors provide a summary of the biological properties and actions of SYK and its involvement in various diseases, discuss information about drugs that have been developed as SYK inhibitors for the treatment of ITP, and consider other potential uses for drugs that inhibit SYK. Although several drugs are being developed, the only SYK inhibitor that is currently available for the treatment of ITP is a drug called fostamatinib. In patients with ITP, including those who no longer respond to other treatments, fostamatinib has been shown to improve platelet counts and reduce bleeding events. Researchers are also currently investigating the use of drugs that inhibit SYK, including fostamatinib, for the potential treatment of other diseases associated with inflammation (e.g. rheumatoid arthritis, COVID-19), autoimmunity (e.g. warm autoimmune hemolytic anemia), and blood cancers (e.g. lymphoma, chronic lymphocytic leukemia, and acute myeloid leukemia).

Effect of Anticoagulant Therapy for 6 Weeks vs 3 Months on Recurrence and Bleeding Events in Patients Younger Than 21 Years of Age With Provoked Venous Thromboembolism: The Kids-DOTT Randomized Clinical Trial.

Importance: Among patients younger than 21 years of age, the optimal duration of anticoagulant therapy for venous thromboembolism is unknown. Objective: To test the hypothesis that a 6-week duration of anticoagulant therapy for provoked venous thromboembolism is noninferior to a conventional 3-month therapy duration in patients younger than 21 years of age. Design, Setting, and Participants: Randomized clinical trial involving 417 patients younger than 21 years of age with acute, provoked venous thromboembolism enrolled at 42 centers in 5 countries from 2008-2021. The main exclusions were severe anticoagulant deficiencies or prior venous thromboembolism. Patients without persistent antiphospholipid antibodies and whose thrombi were resolved or not completely occlusive upon repeat imaging at 6 weeks after diagnosis underwent randomization. The final visit for the primary end points occurred in January 2021. Interventions: Total duration for anticoagulant therapy of 6 weeks (n = 207) vs 3 months (n = 210) for provoked venous thromboembolism. Main Outcomes and Measures: The primary efficacy and safety end points were centrally adjudicated symptomatic recurrent venous thromboembolism and clinically relevant bleeding events within 1 year blinded to treatment group. The primary analysis was noninferiority in the per-protocol population. The noninferiority boundary incorporated a bivariate trade-off that included an absolute increase of 0% in symptomatic recurrent venous thromboembolism with an absolute risk reduction of 4% in clinically relevant bleeding events (1 of 3 points on the bivariate noninferiority boundary curve). Results: Among 417 randomized patients, 297 (median age, 8.3 [range, 0.04-20.9] years; 49% female) met criteria for the primary per-protocol population analysis. The Kaplan-Meier estimate for the 1-year cumulative incidence of the primary efficacy outcome was 0.66% (95% CI, 0%-1.95%) in the 6-week anticoagulant therapy group and 0.70% (95% CI, 0%-2.07%) in the 3-month anticoagulant therapy group, and for the primary safety outcome, the incidence was 0.65% (95% CI, 0%-1.91%) and 0.70% (95% CI, 0%-2.06%). Based on absolute risk differences in recurrent venous thromboembolism and clinically relevant bleeding events between groups, noninferiority was demonstrated. Adverse events occurred in 26% of patients in the 6-week anticoagulant therapy group and in 32% of patients in the 3-month anticoagulant therapy group; the most common adverse event was fever (1.9% and 3.4%, respectively). Conclusions and Relevance: Among patients younger than 21 years of age with provoked venous thromboembolism, anticoagulant therapy for 6 weeks compared with 3 months met noninferiority criteria based on the trade-off between recurrent venous thromboembolism risk and bleeding risk. Trial Registration: ClinicalTrials.gov Identifier: NCT00687882.

Pegylated interferon alfa-2a for polycythemia vera or essential thrombocythemia resistant or intolerant to hydroxyurea.

Prior studies have reported high response rates with recombinant interferon-α (rIFN-α) therapy in patients with essential thrombocythemia (ET) and polycythemia vera (PV). To further define the role of rIFN-α, we investigated the outcomes of pegylated-rIFN-α2a (PEG) therapy in ET and PV patients previously treated with hydroxyurea (HU). The Myeloproliferative Disorders Research Consortium (MPD-RC)-111 study was an investigator-initiated, international, multicenter, phase 2 trial evaluating the ability of PEG therapy to induce complete (CR) and partial (PR) hematologic responses in patients with high-risk ET or PV who were either refractory or intolerant to HU. The study included 65 patients with ET and 50 patients with PV. The overall response rates (ORRs; CR/PR) at 12 months were 69.2% (43.1% and 26.2%) in ET patients and 60% (22% and 38%) in PV patients. CR rates were higher in CALR-mutated ET patients (56.5% vs 28.0%; P = .01), compared with those in subjects lacking a CALR mutation. The median absolute reduction in JAK2V617F variant allele fraction was -6% (range, -84% to 47%) in patients achieving a CR vs +4% (range, -18% to 56%) in patients with PR or nonresponse (NR). Therapy was associated with a significant rate of adverse events (AEs); most were manageable, and PEG discontinuation related to AEs occurred in only 13.9% of subjects. We conclude that PEG is an effective therapy for patients with ET or PV who were previously refractory and/or intolerant of HU. This trial was registered at www.clinicaltrials.gov as #NCT01259856.

The role of total ankle replacement in patients with haemophilia and end-stage ankle arthropathy: A review.

Haemophilia is the most common X-linked bleeding disorder, affecting over 1 million individuals throughout the world. Patients are subclassified into mild, moderate and severe disease based on per cent factor activity level. Nearly, all patients with haemophilia develop haemophilic arthropathy (HA) by age 30 and HA is known to have a negative impact on physical health subscores in Haem-A-QOL, a validated quality of life scoring system for patients with haemophilia. Unfortunately, many patients progress to end-stage HA of the ankle, which is characterized by pain, contractures, decreased range of motion and muscle atrophy. Ankle arthrodesis (AAD) has been the standard of care in the definitive surgical management of end-stage HA of the ankle. While AAD is a safe surgical procedure known to improve HA-related pain, it decreases functional mobility and has been associated with secondary hindfoot arthritis as well as subtalar degeneration. In recent years, total ankle replacement (TAR) has emerged as an alternative surgical procedure that strives to improve functional mobility, pain and quality of life in end-stage HA of the ankle. However, the safety, durability, and efficacy of this procedure in these patients are unknown. In this review, we analyse the clinical studies investigating TAR in patients with end-stage HA of the ankle. We also discuss important considerations in the perioperative management of patients with haemophilia and compare the risks and benefits of AAD and TAR for patients with end-stage HA of the ankle.

PERSEPT 3: A phase 3 clinical trial to evaluate the haemostatic efficacy of eptacog beta (recombinant human FVIIa) in perioperative care in subjects with haemophilia A or B with inhibitors.

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.

The safety of activated eptacog beta in the management of bleeding episodes and perioperative haemostasis in adult and paediatric haemophilia patients with inhibitors.

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.

Emicizumab Prophylaxis in Hemophilia A with Inhibitors.

BACKGROUND: Emicizumab (ACE910) bridges activated factor IX and factor X to restore the function of activated factor VIII, which is deficient in persons with hemophilia A. This phase 3, multicenter trial assessed once-weekly subcutaneous emicizumab prophylaxis in persons with hemophilia A with factor VIII inhibitors. METHODS: We enrolled participants who were 12 years of age or older. Those who had previously received episodic treatment with bypassing agents were randomly assigned in a 2:1 ratio to emicizumab prophylaxis (group A) or no prophylaxis (group B). The primary end point was the difference in bleeding rates between group A and group B. Participants who had previously received prophylactic treatment with bypassing agents received emicizumab prophylaxis in group C. RESULTS: A total of 109 male participants with hemophilia A with inhibitors were enrolled. The annualized bleeding rate was 2.9 events (95% confidence interval [CI], 1.7 to 5.0) among participants who were randomly assigned to emicizumab prophylaxis (group A, 35 participants) versus 23.3 events (95% CI, 12.3 to 43.9) among those assigned to no prophylaxis (group B, 18 participants), representing a significant difference of 87% in favor of emicizumab prophylaxis (P<0.001). A total of 22 participants in group A (63%) had zero bleeding events, as compared with 1 participant (6%) in group B. Among 24 participants in group C who had participated in a noninterventional study, emicizumab prophylaxis resulted in a bleeding rate that was significantly lower by 79% than the rate with previous bypassing-agent prophylaxis (P<0.001). Overall, 198 adverse events were reported in 103 participants receiving emicizumab prophylaxis; the most frequent events were injection-site reactions (in 15% of participants). Thrombotic microangiopathy and thrombosis were reported in 2 participants each (in the primary analysis) who had received multiple infusions of activated prothrombin complex concentrate for breakthrough bleeding. No antidrug antibodies were detected. CONCLUSIONS: Emicizumab prophylaxis was associated with a significantly lower rate of bleeding events than no prophylaxis among participants with hemophilia A with inhibitors. (Funded by F. Hoffmann-La Roche and Chugai Pharmaceutical; HAVEN 1 ClinicalTrials.gov number, NCT02622321 .).

Antiphospholipid antibodies and recurrent thrombosis after a first unprovoked venous thromboembolism.

It is uncertain whether antiphospholipid antibodies (APAs) increase the risk of recurrence after a first unprovoked venous thromboembolism (VTE). We tested for anticardiolipin antibodies, anti-ß2 glycoprotein 1 antibodies, and lupus anticoagulant on 2 occasions ∼6 months apart in 307 patients with a first unprovoked VTE who were part of a prospective cohort study. We then determined if APAs were associated with recurrent thrombosis in the 290 patients who stopped anticoagulant therapy in response to negative D-dimer results. Compared with those without an APA, the hazard ratios for recurrent VTE were 1.8 (95% confidence interval [CI], 0.9-3.7; P = .09) in the 25.9% of patients with an APA on ≥1 occasions, 2.7 (95% CI, 1.1-.7; P = .03) in the 9.0% of patients with the same APA on 2 occasions, and 4.5 (95% CI, 1.5-13.0; P = .006) in the 3.8% of patients with 2 or 3 different APA types on either the same or different occasions. There was no association between having an APA and D-dimer levels. We conclude that having the same type of APA on 2 occasions or having >1 type of APA on the same or different occasions is associated with recurrent thrombosis in patients with a first unprovoked VTE who stop anticoagulant therapy in response to negative D-dimer tests. APA and D-dimer levels seem to be independent predictors of recurrence in patients with an unprovoked VTE. This trial was registered at www.clinicaltrials.gov as #NCT00720915.

International recommendations on the diagnosis and treatment of acquired hemophilia A.

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.