Thrombosis and Thrombocytopenia after ChAdOx1 nCoV-19 Vaccination.

We report findings in five patients who presented with venous thrombosis and thrombocytopenia 7 to 10 days after receiving the first dose of the ChAdOx1 nCoV-19 adenoviral vector vaccine against coronavirus disease 2019 (Covid-19). The patients were health care workers who were 32 to 54 years of age. All the patients had high levels of antibodies to platelet factor 4-polyanion complexes; however, they had had no previous exposure to heparin. Because the five cases occurred in a population of more than 130,000 vaccinated persons, we propose that they represent a rare vaccine-related variant of spontaneous heparin-induced thrombocytopenia that we refer to as vaccine-induced immune thrombotic thrombocytopenia.

Health-related quality of life and physical activity in Nordic patients with moderate haemophilia A and B (the MoHem study).

INTRODUCTION: The impact of moderate haemophilia on health-related quality of life (HRQoL) and physical activity (PA) is not well known. In previous studies, persons with factor VIII/factor IX activity (FVIII/FIX:C) below 3 IU/dL were associated with a more severe bleeding phenotype than predicted. AIM: To explore HRQoL and PA in patients with moderate haemophilia A (MHA) and B (MHB). METHODS: A cross-sectional, multicentre study covering patients with MHA and MHB in Sweden, Finland, and Norway. HRQoL was assessed with the EuroQoL 5-Dimensions (EQ-5D) form and PA with the International Physical Activity Questionnaire among participants aged ≥15 years. RESULTS: We report on 104 patients aged 15-84 years from the MoHem study. Overall, EQ-5D utility was .85 (median) (Q1-Q3 0.73-1.0) with corresponding visual analogue scale (VAS) 80 (70-90), which were similar regardless of treatment modality, FVIII/FIX:C, and MHA or MHB. Pain and mobility were most frequently affected dimensions. Utility (r = -.54), VAS (r = -.42), and PA (r = -.32) correlated negatively with arthropathy (HJHS). Only patients aged 41-50 years displayed lower utility (p = .02) and VAS (p < .01) than the Norwegian population norm. Patients on prophylaxis aged 35-54 years reported higher PA than those treated on-demand (p = .01). CONCLUSION: Haemophilic arthropathy had negative impact on HRQoL and PA in Nordic patients with moderate haemophilia. Middle-aged patients captured lower utility and VAS than observed in the general population. Tailored prophylaxis and improved joint health may influence positively on HRQoL and PA also in moderate haemophilia.

Platelet function testing: Current practice among clinical centres in Northern Europe.

INTRODUCTION: Platelet function tests are used to screen and diagnose patients with possible inherited platelet function defects (IPFD). Some acquired platelet dysfunction may be caused by certain drugs or comorbidities, which need to be excluded before testing. AIMS: To identify current practice among centres performing platelet function tests in Northern Europe. METHODS: A total of 14 clinical centres from Sweden (six), Finland (two), Denmark (two), Norway (one), Estonia (two) and Iceland (one) completed the survey questionnaire, the population capture area of about 29.5 million. RESULTS: Six of the 14 (42.8%) centres providing platelet function assessment represent comprehensive treatment centres (EUHANET status). A Bleeding score (BS) or ISTH bleeding assessment tool (ISTH BAT score) is evaluated in 11/14 (78.6%) centres and family history in all. Five/14 centres (35.7%) use structured preanalytical patient instructions, and 10/14 (71.4%) recorded questionnaire on the preassessment of avoidance of any drugs or natural products affecting platelet functions. Preliminary investigations of screening tests of coagulation are performed in 10/14 (71.4%), while in 4/14 (28.6%), the diagnostic work-up of IPFD and von Willebrand disease (VWD) is performed simultaneously. The work-up of IPFD includes peripheral blood smear in 10/14 (71.4%), platelet aggregometry in all, flow cytometry in 10/14 (71.4%) and Platelet Function Analysis (PFA) in 3/11 (28.6%). Molecular genetic diagnosis is available in 7/14 (50%) centres. CONCLUSIONS: The considerable variability in the current practice illustrates the need for harmonization between the Northern European centres according to the international registers (i.e. EUHASS) and IPFD guidelines (ISTH, EHA).

Immune complexes, innate immunity, and NETosis in ChAdOx1 vaccine-induced thrombocytopenia.

AIMS: We recently reported five cases of vaccine-induced immune thrombotic thrombocytopenia (VITT) 7-10 days after receiving the first dose of the ChAdOx1 nCoV-19 adenoviral vector vaccine against corona virus disease 2019 (COVID-19). We aimed to investigate the pathogenic immunological responses operating in these patients. METHODS AND RESULTS: We assessed circulating inflammatory markers by immune assays and immune cell phenotyping by flow cytometry analyses and performed immunoprecipitation with anti-platelet factor (PF)4 antibody in plasma samples followed by mass spectrometry from all five patients. A thrombus was retrieved from the sinus sagittal superior of one patient and analysed by immunohistochemistry and flow cytometry. Precipitated immune complexes revealed multiple innate immune pathway triggers for platelet and leucocyte activation. Plasma contained increased levels of innate immune response cytokines and markers of systemic inflammation, extensive degranulation of neutrophils, and tissue and endothelial damage. Blood analyses showed activation of neutrophils and increased levels of circulating H3Cit, dsDNA, and myeloperoxidase-DNA complex. The thrombus had extensive infiltration of neutrophils, formation of neutrophil extracellular traps (NETs), and IgG deposits. CONCLUSIONS: The results show that anti-PF4/polyanion IgG-mediated thrombus formation in VITT patients is accompanied by a massive innate immune activation and particularly the fulminant activation of neutrophils including NETosis. These results provide novel data on the immune response in this rare adenoviral vector-induced VITT.

Bleeding phenotype of patients with moderate haemophilia A and B assessed by thromboelastometry and thrombin generation.

INTRODUCTION: Predicting the bleeding phenotype is crucial for the management of patients with moderate haemophilia. Global coagulation assays evaluate haemostasis more comprehensively than conventional methods. AIM: To explore global coagulation assays and the bleeding phenotype of patients with moderate haemophilia A (MHA) and B (MHB). METHODS: The MoHem study is a cross-sectional, multicentre study covering Nordic patients with MHA and MHB. Thromboelastometry in whole blood and thrombin generation (TG) in platelet-poor plasma (1, 2.5 and 5 pM tissue factor (TF)) were compared with joint health (Haemophilia Joint Health Score (HJHS)) and treatment modality. RESULTS: We report on 61 patients from Oslo and Helsinki: 24 MHA and 37 MHB. By TG (2.5 pM TF), patients who had been without replacement therapy during the previous 12 months depicted higher endogenous thrombin potential (P = .03). In contrast, those who had low ETP (< median) captured higher HJHS (P = .02). Patients who had undergone orthopaedic surgery generated least thrombin (P = .02). By thromboelastometry, those without the need of factor consumption had short clotting times, and quick times to maximum velocity (< median values) (P = .03). Factor VIII/factor IX activity (FVIII/FIX:C) did not align with the bleeding phenotype, but FIX:C ≤ 3 IU/dL was associated with lower peak thrombin (P = .03). CONCLUSION: TG differentiated patients with moderate haemophilia according to HJHS, annual factor consumption, and whether orthopaedic surgery had been performed. Thromboelastometry differentiated according to factor consumption only. Global coagulation assays may assist predicting the bleeding phenotype in moderate haemophilia.

Haemophilia early arthropathy detection with ultrasound and haemophilia joint health score in the moderate haemophilia (MoHem) study.

INTRODUCTION: Detection of early arthropathy is crucial for the management of haemophilia, but data on moderate haemophilia are limited. Therefore, we evaluated joint health and treatment modalities in Nordic patients with moderate haemophilia A (MHA) and B (MHB). AIM: To explore and compare the Haemophilia Early Arthropathy Detection with Ultrasound (HEAD-US) and Haemophilia Joint Health Score (HJHS) to detect early arthropathy in moderate haemophilia. METHODS: A cross-sectional, multicentre study covering Nordic patients with MHA and MHB. Arthropathy was evaluated by HEAD-US and HJHS 2.1. RESULTS: We assessed 693 joints in 118 patients. HEAD-US scores (medians [interquartile ranges]) were as follows: elbows 0 points (0-0), knees 0 (0-0) and ankles 0 (0-1). Respectively, by HJHS: elbows 0 (0-1), knees 0 (0-1) and ankles 0 (0-1). Cartilage (14%) and bone (13%) were most commonly affected by HEAD-US. Frequent HJHS findings were crepitus on motion in knees (39%), and loss of flexion (23%) and extension (13%) in ankles. HEAD-US correlated strongly with HJHS (elbows r = .70, knees r = .60 and ankles r = .65), but 24% had discordant scores. Joints with HJHS zero points, 5% captured HEAD-US ≥1 point. Moreover, 26% had HJHS findings without HEAD-US pathology. Notably, 31% of knees had crepitus on motion and normal HEAD-US. CONCLUSION: Overall, the joints attained low scores implying good joint health. HEAD-US correlated strongly with HJHS. In 5%, HEAD-US detected subclinical pathology. Crepitus on motion was frequently reported despite normal HEAD-US, thus not necessarily reflecting arthropathy. HEAD-US therefore improves the joint assessment in moderate haemophilia.

Joint health and treatment modalities in Nordic patients with moderate haemophilia A and B - The MoHem study.

INTRODUCTION: The prevalence of arthropathy in moderate haemophilia A (MHA) and B (MHB) is not well known. AIM: We evaluated joint health in Nordic patients in relation to their treatment modality. METHODS: A cross-sectional, multicentre study covering MHA and MHB in Sweden, Finland and Norway. Arthropathy was evaluated by ultrasound (HEAD-US) and Haemophilia Joint Health Score (HJHS). RESULTS: We report on 145 patients: median age 28 years (IQR 13-52) and 61% MHA. Baseline factor VIII/factor IX activity (FVIII/FIX:C) was 2 IU/dL (median) (IQR 2-4): lower for MHB (2 IU/dL, IQR 1-2) than MHA (3 IU/dL, IQR 2-4) (P < .01). Eighty-five per cent of MHA and 73% MHB had a history of haemarthrosis (P = .07). Age at first joint bleed was lower for MHA (5 years [median], IQR 3-7) than MHB (7 years, IQR 5-12) (P = .01). Thirty-eight per cent received prophylaxis, started at median 10 years of age (IQR 4-24). Median joint bleeds and serious other bleeds during the last 12 months were both zero (IQR 0-1). Total HEAD-US captured 0/48 points (median) (IQR 0-2) and HJHS 4/120 points (IQR 1-10) with strong correlation between them (r = .72). FVIII/FIX: C ≤ 3 IU/dL was associated with higher HJHS (P = .04). Fifteen per cent had undergone orthopaedic surgery. CONCLUSION: The current joint health in Nordic moderate haemophilia patients was rather good, but a subgroup had severe arthropathy. FVIII/FIX: C ≤ 3 IU/dL and MHA were associated with a more severe bleeding phenotype. We suggest primary prophylaxis to all patients with FVIII/FIX:C ≤ 3 IU/dL.

A dominant STIM1 mutation causes Stormorken syndrome.

Stormorken syndrome is a rare autosomal-dominant disease with mild bleeding tendency, thrombocytopathy, thrombocytopenia, mild anemia, asplenia, tubular aggregate myopathy, miosis, headache, and ichthyosis. A heterozygous missense mutation in STIM1 exon 7 (c.910C>T; p.Arg304Trp) (NM_003156.3) was found to segregate with the disease in six Stormorken syndrome patients in four families. Upon sensing Ca(2+) depletion in the endoplasmic reticulum lumen, STIM1 undergoes a conformational change enabling it to interact with and open ORAI1, a Ca(2+) release-activated Ca(2+) channel located in the plasma membrane. The STIM1 mutation found in Stormorken syndrome patients is located in the coiled-coil 1 domain, which might play a role in keeping STIM1 inactive. In agreement with a possible gain-of-function mutation in STIM1, blood platelets from patients were in a preactivated state with high exposure of aminophospholipids on the outer surface of the plasma membrane. Resting Ca(2+) levels were elevated in platelets from the patients compared with controls, and store-operated Ca(2+) entry was markedly attenuated, further supporting constitutive activity of STIM1 and ORAI1. Thus, our data are compatible with a near-maximal activation of STIM1 in Stormorken syndrome patients. We conclude that the heterozygous mutation c.910C>T causes the complex phenotype that defines this syndrome.

Report on 4 cases with decreased recovery due to neutralizing antibodies specific for PEGylated recombinant factor VIII.

BACKGROUND: The immunogenicity, safety, and efficacy of recombinant factor VIII (rFVIII) have gained increasing interest after the introduction of extended half-life products with various modifications of the rFVIII molecule, such as covalent attachment of polyethylene glycol (PEG). Anti-PEG antibodies may be associated with a temporary reduction of FVIII recovery, but according to previous studies, they usually disappear after continuous dosing. Anti-PEG antibodies with an inhibitory capacity have never been demonstrated in patients treated with PEGylated rFVIII products. OBJECTIVES: To routinely switch from standard half-life to PEGylated extended half-life rFVIII products in patients with hemophilia A. METHODS: From December 2022 until May 2023, 83 adults with hemophilia A attending Oslo Haemophilia Comprehensive Care Centre received a test dose with a PEGylated rFVIII product to switch treatment. Four patients presented with decreased recovery without the presence of an FVIII inhibitor. Accordingly, we performed a variant inhibitor test utilizing different rFVIII concentrates as a source of FVIII and enzyme-linked immunosorbent assay to search for anti-PEG antibodies. RESULTS: We found inhibitory anti-PEG/anti-PEGylated rFVIII antibodies in 4 patients (5%), both persistent and transient, explaining the impaired recovery. The patients had neutralizing anti-PEG antibodies prior to the first dosing of PEGylated rFVIII. We demonstrated neutralizing antibodies (mainly immunoglobuline G) specific for PEG and all 3 commercially available PEGylated rFVIII products. CONCLUSION: The number of patients with inhibitory anti-PEG antibodies was significant, and the presence of inhibitors against PEGylated rFVIII emphasizes the importance of individual monitoring when switching FVIII concentrates to ensure safety and efficacy of the treatment.

Real-world data in patients with congenital hemophilia and inhibitors: final data from the FEIBA Global Outcome (FEIBA GO) study.

Background: The bypassing agent, activated prothrombin complex concentrate [aPCC, FEIBA (factor VIII inhibitor bypass activity); Baxalta US Inc, a Takeda company, Lexington, MA, USA], is indicated for the treatment of bleeding episodes, perioperative management, and routine prophylaxis in patients with hemophilia A or B with inhibitors. In certain countries, aPCC is also indicated for the treatment of bleeding episodes and perioperative management in patients with acquired hemophilia A. Objectives: To describe long-term, real-world effectiveness, safety, and quality-of-life outcomes for patients with congenital hemophilia A or B and high-responding inhibitors receiving aPCC treatment in routine clinical practice. Design: FEIBA Global Outcome (FEIBA GO; EUPAS6691) was a prospective, observational study. Methods: Investigators determined the treatment regimen and clinical monitoring frequency. The planned patient observation period was 4 years. Data are from the safety analysis set (patients who received ⩾1 aPCC infusion). Results: Overall, 50 patients received either aPCC prophylaxis (n = 37) or on-demand therapy (n = 13) at screening [hemophilia A, n = 49; hemophilia B, n = 1; median (range) age, 16.5 [2-71] years). Mean ±â€„standard deviation overall annualized bleeding rate and annualized joint bleeding rate for patients receiving prophylaxis were 6.82 ± 11.52 and 3.77 ± 5.71, respectively, and for patients receiving on-demand therapy were 10.94 ± 11.27 and 6.94 ± 7.39, respectively. Overall, 177 and 31 adverse events (AEs) were reported in 28 of 40 and 10 of 13 patients receiving prophylaxis or on-demand therapy, respectively. Two serious AEs were considered possibly related to aPCC: acute myocardial infarction due to coronary artery embolism in one patient receiving prophylaxis. No thrombotic microangiopathy was reported. No AEs resulted in death. Conclusion: This study demonstrated the long-term, real-world effectiveness and consistent safety profile of aPCC as on-demand therapy and prophylactic treatment in patients with hemophilia and high-responding inhibitors. Trial registry: FEIBA Global Outcome Study; EUPAS6691 https://www.encepp.eu/encepp/viewResource.htm?id=32774.

Fixed doses of N8-GP prophylaxis maintain moderate-to-mild factor VIII levels in the majority of patients with severe hemophilia A.

BACKGROUND: N8-GP is an extended half-life recombinant factor VIII developed for prophylaxis and treatment of bleeds in patients with hemophilia A. OBJECTIVE: To assess pharmacokinetic (PK) characteristics of N8-GP in previously treated patients with severe hemophilia A, model the time spent at hemophilia thresholds of ≥1 and ≤5 IU/dL (moderate) or >5 IU/dL (mild) FVIII levels during N8-GP prophylaxis, and investigate the relationship between N8-GP half-life and von Willebrand factor (vWF). METHODS: PK assessments were obtained from patients with severe hemophilia A (FVIII < 1 IU/dL) participating in 4 clinical trials: pathfinder 1 (20-60 years); pathfinder 2 (12-17 and ≥18 years); pathfinder 5 (0-11 years), and pathfinder 7 (25-71 years). All PK profiles were assessed after washout and considered single-dose PK profiles. Pre- and postdose FVIII activity at steady state was measured at all visits. RESULTS: From 69 patients, 108 PK profiles of N8-GP 50 IU/kg were assessed. Adults/adolescents received 50 IU/kg every 4 days, achieving mean trough levels of 3.0 IU/dL (95% confidence interval, 2.6-3.5, adults) and 2.7 IU/dL (1.8-4.0, adolescents). Children received 60 IU/kg twice weekly, leading to mean trough levels of 1.2 IU/dL (0.8-1.6, 0- to 5-year-olds) and 2.0 IU/dL (1.5-2.7, 6- to 11-year-olds). PK modeling predicted children dosed every 3 days and adults/adolescents dosed every 3 to 4 days would maintain FVIII levels >5 and >1 IU/dL for >80% and 100% of the time, respectively. N8-GP half-life correlated linearly with von Willebrand factor levels in adults/adolescents, less in children. CONCLUSIONS: Prophylaxis with fixed intervals (Q4D/twice weekly) and fixed weight-based dosing (50/60 IU/kg) ensured >1 IU/dL FVIII trough levels in both adults and children.

Hypercoagulability in patients with haematological neoplasia: no apparent initiation by tissue factor.

Patients with haematological malignancies carry increased risk of venous thrombosis (VT). However, the mechanisms that link these malignancies to activated coagulation have not been fully identified. Since anti-haemostatic agents are studied in clinical trials for their potential to prolong survival in cancer patients, a detailed characterisation of haemostatic markers in cancer subtypes is needed. Hence, in this study, we measured the plasma concentrations and mRNA expression in blood mononuclear cells of haemostatic parameters in 93 patients with haematological neoplasias (acute myeloid leukaemia, chronic lymphatic leukaemia, multiple myeloma, and non-Hodgkin's lymphoma) before start and after completion of cancer therapy. At diagnosis we found activation of coagulation and fibrinolysis, especially in patients with acute myeloid leukaemia. This hypercoagulation was not associated with increased levels of tissue factor (TF) or factor VII (fVII) antigen or mRNA, or levels of activated fVII. In conclusion we found a hypercoagulable state in patients with haematological malignancy that did not seem to be initiated by TF.

The reversal effect of prothrombin complex concentrate (PCC), activated PCC and recombinant activated factor VII in apixaban-treated patients in vitro.

BACKGROUND: The number of patients under treatment with FXa inhibitors is increasing, but there is no concensus on how to reverse their anticoagulant effect in case of a life-threatening bleeding. A specific antidote is not yet commercially available. Prothrombin complex concentrate (PCC), activated PCC (aPCC) and recombinant factor VIIa (rFVIIa) are suggested available reversal agents. OBJECTIVES: To find the most effective reversal agent to apixaban and to determine the optimal dose. PATIENTS/METHODS: PCC, aPCC, and rFVIIa at concentrations imitating 80%, 100%, and 125% of suggested therapeutic doses were added to blood drawn from apixaban-treated patients (n=30). aPCC was also tested in a 50% dose. Samples from healthy subjects (n=40) were used as controls. Thromboelastometry in whole blood (WB) and thrombin generation in platelet-poor plasma (PPP) were measured to assess the reversal effect. RESULTS: aPCC shortened clotting time (CT) in WB, and increased the peak thrombin concentration and velocity index in PPP to a greater extent than PCC and rFVIIa. No significant differences were seen between rFVIIa and aPCC on thrombin generation lag time, or between PCC and aPCC on endogenous thrombin potential (ETP). The 50% dose of aPCC had a slightly inferior effect, but was comparable to the other reversal agents. CONCLUSIONS: In this in vitro study the 80% dose of aPCC (40 IU/kg) reversed the anticoagulant effect of apixaban more effectively than the corresponding dose of rFVIIa and PCC both in WB (CT) and PPP (peak, ETP).

Pharmacodynamics of recombinant activated factor VII and plasma-derived factor VII in a cohort of severe FVII deficient patients.

Recombinant activated factor VII (rFVIIa) and plasma-derived factor VII (pdFVII) are used to prevent bleedings in severe FVII deficient patients, despite their short half-lifes. It is suggested that FVII levels of 15-20 IU/dL are sufficient to maintain hemostasis. We analyzed the pharmacodynamic effects of FVII substitution therapy in the Nijmegen Hemostasis Assay (NHA) that simultaneously measures thrombin and plasmin generation. Ten severe FVII deficient patients were treated with 20 µg/kg rFVIIa or 25 IU/kg pdFVII in a cross-over design. Thrombin generation lag-time (TG-LT) was identified as an effect-response parameter. Pharmacodynamic analysis using a maximum effect model showed 50% reduction of the TG-LT effect at ~2 IU/dL FVII activity for both rFVIIa and pdFVII. The FVII activity to obtain TG-LT comparable to the upper limit of normal range in healthy controls (4 min) was given by the effective concentration (ECnormal), showing sufficient hemostasis at 3-4 IU/dL FVII activity. No association was seen between FVII activity and other thrombin or plasmin generation parameters as measured by NHA. In conclusion, 3-4 IU/dL FVII activity seems sufficient to maintain hemostasis in patients with severe FVII deficiency during prophylaxis. These data may suggest a potential value for measurement of TG-LT in the monitoring of FVII(a) therapy.