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Abstract Background Unfractionated heparin (UFH) is primarily monitored using activated partial thromboplastin time (APTT). However, the recent introduction of anti-activated factor X (anti-Xa) activity testing has provided a direct evaluation of Xa inhibition by anticoagulants. This study aimed to investigate discrepancies between APTT and anti-Xa activity during UFH monitoring in critically ill patients and explore their underlying causes. Methods This study analyzed 271 pairs of laboratory test results from blood samples of 99 critically ill patients receiving continuous intravenous UFH. Theoretical APTT values were calculated using fitted curve equations from spiked sample measurements with anti-Xa activity. Samples were categorized into three groups based on the measurement of the APTT/theoretical APTT ratio: the lower group ( 120%). Results The overall concordance rate between APTT and anti-Xa activity was 45%, with a 55% discrepancy rate. The lower group frequently showed apparent heparin overdoses, while coagulation factor activities in the lower and upper groups were higher and lower, respectively, than those in the concordant group. Particularly, the lower group exhibited higher factor VIII activity levels than the upper and concordant groups. Conclusions Discrepancies between APTT and anti-Xa activity were frequently observed, influenced by changes in coagulation factors activity levels. The lower and upper groups were classified as pseudo-heparin-resistant and coagulopathy types, respectively. Accurate monitoring of heparin in critically ill patients is crucial, especially in cases of pseudo-heparin resistance, where APTT values may wrongly indicate inadequate heparin dosing despite sufficient anti-Xa activity. Understanding these discrepancies is important for managing heparin therapy in critically ill patients. Trial registration: Not applicable.

Prophylactic treatment with emicizumab has become an important and effective bleeding prevention for people with hemophilia A (PwHA). Perioperative management of PwHA using emicizumab prophylaxis is still challenging due to a lack of experience. Medical records of perioperative management and outcomes were reviewed, and data were collected for adult PwHA receiving emicizumab and undergoing surgical procedures between August 2019 and July 2022 at the University Medical Center Ljubljana. Twelve surgical procedures were performed in eight PwHA (one with FVIII inhibitors) while on emicizumab prophylaxis. Three minor procedures included cataract surgery, cystoscopic lithotripsy, and percutaneous coronary intervention. Nine major surgeries included four osteosyntheses, necrectomy of chronic osteomyelitis with new ankle arthrodesis, two below-knee amputations, total knee replacement, and placement of ventriculostomy after a spontaneous intraventricular hemorrhage. No major bleeds, thrombotic events or deaths, or new inhibitors appeared. Our real-world experience demonstrates that minor and major surgeries can be performed safely in PwHA on emicizumab prophylaxis. Additional data are needed to optimize dosing/duration of additional hemostatic agents in diverse invasive procedures and complex clinical situations.

Abstract Background Fluorogenic thrombin generation (TG) is a global hemostasis assay that provides an overall representation of hemostasis potential. However, the accurate detection of thrombin activity in plasma may be affected by artifacts inherent to the assay-associated fluorogenic substrate. The significance of the fluorogenic artifacts or their corrections has not been studied in hemophilia treatment applications. Methods We sought to investigate TG in hemophilia plasma samples under typical and worst-case fluorogenic artifact conditions and assess the performance of artifact correction algorithms. Severe hemophilic plasma with or without added Factor VIII (FVIII) was evaluated using commercially available and in-house TG reagents, instruments, and software packages. The inner filter effect (IFE) was induced by spiking elevated amounts of fluorophore 7-amino-4-methylcoumarin (AMC) into plasma prior to the TG experiment. Substrate consumption was modeled by adding decreasing amounts of Z-Gly-Gly-Arg-AMC (ZGGR-AMC) to plasma or performing TG in antithrombin deficient plasma. Results All algorithms corrected the AMC-induced IFE and antithrombin-deficiency induced substrate consumption up to a certain level of either artifact (edge of failure) upon which TG results were not returned or overestimated. TG values in FVIII deficient (FVIII-DP) or supplemented plasma were affected similarly. Normalization of FVIII-DP resulted in a more accurate correction of substrate artifacts than algorithmic methods. Conclusions Correction algorithms may be effective in situations of moderate fluorogenic substrate artifacts inherent to highly procoagulant samples, but correction may not be required under typical conditions for hemophilia treatment studies if TG parameters can be normalized to a reference plasma sample.

Developing mouse models of hemophilia A has been shown to facilitate in vivo studies to explore the probablemechanism(s) underlying the disease and to examine the efficiency of the relevant potential therapeutics. This studyaimed to knockout (KO) the coagulation factor viii (fviii) gene in NMRI mice, using CRISPR/Cas9 (D10A/nickase) system,to generate a mouse model of hemophilia A. Two single guide RNAs (sgRNAs), designed from two distinct regions onNMRI mouse FVIII (mFVIII) exon 3, were designed and inserted in the pX335 vector, expressing both sgRNAs andnickase. The recombinant construct was delivered into mouse zygotes and implanted into the pseudopregnant femalemice’s uterus. Mutant mice were identified by genotyping, genomic sequencing, and mFVIII activity assessment. Twoseparate lines of hemophilia A were obtained through interbreeding the offspring of the female mice receiving potentialCRISPR-Cas9-edited zygotes. Genomic DNA analysis revealed disruptions of the mfviii gene reading frame througha 22-bp deletion and a 23-bp insertion in two separate founder mice. The founder mice showed all the clinical signsof hemophilia A including; excessive bleeding after injuries, and spontaneous bleeding in joints and other organs.Coagulation test data showed that mFVIII coagulation activity was significantly diminished in the mFVIII knockout(FVIIIKO) mice compared to normal mice. The CRISPR/nickase system was successfully applied to generate mouselines with the knockout fviii gene. The two novel FVIIIKO mice demonstrated all clinical symptoms of hemophilia A, whichcould be successfully inherited. Therefore, both of the developed FVIIIKO mouse lines are eligible for being consideredas proper mouse models of hemophilia A for in vivo therapeutic studies.

In this article, we have demonstrated the feasibility of generating an active form of recombinant blood coagulation factor VIII using an E. coli bacterial expression system as a potential treatment for hemophilia type A. Factor VIII (FVIII), an essential blood coagulation protein, is a key component of the fluid phase blood coagulation system. So far, all available recombinant FVIII formulations have been produced using eukaryotic expression systems. Mammalian cells can produce catalytically active proteins with all the necessary posttranslational modifications. However, cultivating such cells is time-consuming and highly expensive, and the amount of the obtained product is usually low. In contrast to eukaryotic cells, bacterial culture is inexpensive and allows the acquisition of large quantities of recombinant proteins in a short time. With this study, we aimed to obtain recombinant blood coagulation factor VIII using the E. coli bacterial expression system, a method not previously explored for this purpose. Our research encompasses the synthesis of blood coagulation factor VIII and its expression in a prokaryotic system. To achieve this, we constructed a prokaryotic expression vector containing a synthetic factor VIII gene, which was then used for the transformation of an E. coli bacterial strain. The protein expression was confirmed by mass spectrometry, and we assessed the stability of the gene construct while determining the optimal growth conditions. The production of blood coagulation factor VIII by the E. coli bacterial strain was carried out on a quarter-technical scale. We established the conditions for isolation, denaturation, and renaturation of the protein, and subsequently confirmed the activity of FVIII.

Hemophilia A is usually a congenital bleeding disorder, which manifest in males due to its X linked recessive pattern of inheritance. It commonly presents with bruises, uncontrolled bleeding post minor trauma or post circumcision, knee swelling etc. Acquired hemophilia is a rare condition and could be associated with autoimmune diseases. We discuss this rare condition of acquired hemophilia in a female patient who presented with common manifestations but in unlikely host.

Background: Venous thromboembolic events have been reported in persons with hemophilia A who received emicizumab and activated prothrombin complex concentrate (APCC) concomitantly, but the relevant mechanism(s) remains unclear. We speculated that activated protein C (APC) and antithrombin (AT) resistance might be associated with these adverse events. Objectives: To investigate APC and AT resistance in factor (F)VIII–deficient (FVIIIdef) plasma in the presence of emicizumab and APCC. Methods: In pooled normal plasma or FVIIIdef plasma samples mixed with emicizumab (50 μg/mL) and FVIII-bypassing agents, including recombinant FVIIa (2.2 μg/mL), APCC (1.3 IU/mL), or plasma-derived FVIIa/FX (1.5 μg/mL), the suppression effect of AT (0-2.4 μM) and APC (0-16 nM) was assessed by tissue factor–triggered thrombin generation assay. The APC effects in FVIIIdef plasma with the copresence of emicizumab, FII (1.3 μM), and/or FIXa (280 pM) were also examined. Results: The AT resistance in emicizumab and each bypassing agent was not observed. Moreover, APC dose-dependent suppression effect was observed in pooled normal plasma or FVIIIdef plasma mixed with emicizumab and recombinant FVIIa or plasma-derived FVIIa/FX. However, APC-catalyzed inactivation had little effect on thrombin generation assay potential in FVIIIdef plasma spiked with emicizumab and APCC. The addition of FIXa to emicizumab in FVIIIdef plasma could lead to partial APC resistance. Furthermore, FVIIIdef plasma spiked with emicizumab, FIXa, and FII was markedly resistant to APC-mediated inactivation. Conclusion: FII and FIXa in APCCs were key clotting factors for APC resistance in FVIIIdef plasma supplemented with emicizumab and APCCs. The APC resistance in persons with hemophilia A receiving emicizumab and APCC may contribute to venous thromboembolic events.

Background Recombinant von Willebrand factor (rVWF, vonicog alfa, Takeda Pharmaceuticals USA) is indicated in adults diagnosed with von Willebrand disease (VWD). In this study, the exposure–response (ER) relationship between VWF activity (VWF:RCo) or factor VIII activity (FVIII:C) and spontaneous bleeding events (BEs) was evaluated in adults with severe VWD receiving rVWF prophylaxis for up to 1 year.

Introduction: Recombinant porcine FVIII (rpFVIII) (Obizur, Susoctcog‐alfa, Takeda, Japan) is licensed for the treatment of bleeding in acquired Haemophilia A (AHA). The summary of product characteristics state that monitoring should be by one stage assay (OSA) rather than chromogenic assay (CSA). CSA have been shown to underestimate activity when rpFVIII is added to plasma in vitro. Methods: Samples from three AHA patients (n = 21) (pre‐ and post rpFVIII) were assessed using FVIII:C assays; OSA methods: Actin, Actin FS, Actin FSL and Pathromtin SL performed on CS5100i (Sysmex, Kobe, Japan); APTT‐SP, SynthASil and SynthAFax performed on ACL TOP (Werfen, Barcelona, Spain). CSA methods on CS5100i: Siemens Chromogenic Assay, Biophen FVIII:C, Technochrom FVIII:C; on ACL TOP: Rox Factor VIII, Coamatic Factor VIII and CRYOcheck Factor VIII. Results: OSA and CSA varied according to reagent used median OSA 61 IU/dL (range 41.5–81 IU/dL (ANOVA p < 0.0001)) median CSA 46.5 IU/dL (range of method specific medians 36.5–84 IU/dL (ANOVA p < 0.0001)). Amongst OSA, Actin FS was associated with the highest FVIII:C, APTT‐SP was associated with the lowest. Variation in CSA results by different methods was also seen with highest FVIII:C levels obtained using the Technochrom FVIII:C and the lowest levels obtained with Siemens Assay. Conclusion: The relationship between OSA and CSA was not consistent between method or patient. Previously there has been reports of underestimation by CSA in in vitro spiked samples. Investigation into concentration of phospholipids in the APTT reagents may explain some of these variations. [ABSTRACT FROM AUTHOR]

Purpose: To report a rare case of acute renal vein thrombosis (RVT) that was treated with endovascular thrombectomy and lysis, and discuss potential etiology and indications for catheter-directed management. Case report: A 21-year-old female athlete presented with sudden pain in her left flank and vomiting. A 3-phase computed tomography (CT) angiogram identified total occlusion of the left renal vein with no excretion from the swollen tender left kidney. Catheter-directed thrombolysis and thrombectomy were initiated 24 hours after onset of symptoms. Complete resolution of the RVT with normalized renal function was achieved. Post-operative Doppler ultrasound scan confirmed normal renal resistance and flow in the renal vein. The patient was discharged on Apixaban and remains well at 6 months. Combined hormonal contraception via an intra-vaginal ring and raised Factor VIII activity were the only identified risk factors. Conclusion: Acute complete RVT with impaired kidney function is rare. Combined hormonal contraception and increased Factor VIII activity were potential risk factors. Endovascular thrombectomy and lysis restored renal perfusion and function, and can be used effectively in the management of fit patients with acutely compromised kidney function from total renal vein obstruction. [ABSTRACT FROM AUTHOR]

Introduction: With recent approval of the first two gene therapies for haemophilia A and B, educational materials about AAV‐based gene therapy are needed by the haemophilia community for a better understanding of this novel therapeutic approach and helping healthcare providers and patients making personalized choices amongst an increasing array of therapeutic options. Aim: To provide a comprehensive summary of the whole process of AAV‐based gene therapy from basic principles to clinical implementation through an illustrated review. Methods: The authors, with expertise in and knowledge about gene therapy for haemophilia A and B, reviewed relevant articles from PubMed database and translated them into illustrations. Results: The review is divided into eight illustrated sections providing an overview of gene therapy for haemophilia A and B from haemophilia basics and current treatment landscape, principles of the AAV‐based liver‐directed gene therapy, through exploring the efficacy and safety results of published phase III clinical trials, current and future challenges, to implementation in clinical practice, including the hub and spoke models and the patient journey. Conclusion: This illustrated review educates healthcare professionals on AAV‐based gene therapy for haemophilia A and B enabling them to further educate their peers and their patients. [ABSTRACT FROM AUTHOR]

Introduction: Regular, prophylactic intravenous (i.v.) FVIII can be challenging for some patients with haemophilia A. Subcutaneous (s.c.) FVIII administration could provide an alternative treatment option with greater convenience and without the complications associated with venous access. Aim: To assess the safety, pharmacokinetics (PK), bioavailability and efficacy of s.c. OCTA101, a recombinant FVIII with a recombinant von Willebrand factor fragment dimer. Methods: This was a single‐centre, prospective, open‐label, phase I/II study (NCT04046848). Previously treated male patients (≥18 years) with severe haemophilia A were eligible for the study. The primary objective of the study was to assess the safety (including immunogenicity) of OCTA101. Secondary objectives included assessments of PK, bioavailability, and the efficacy of prophylaxis. Results: Thirty patients were treated with OCTA101. FVIII inhibitors developed in five (16.7%) patients during daily prophylaxis with 40–60 IU/kg (three cases) and 12.5 IU/kg (two cases) OCTA101. The trial was therefore terminated. OCTA101 had a 2.5‐fold longer terminal half‐life compared with i.v. rFVIII, and bioavailability was 16.6%. Efficacy data at study termination indicated that daily prophylaxis with 40–60 IU/kg OCTA101 was efficacious in the absence of FVIII inhibitors. Conclusions: Despite promising PK and efficacy results, the trial was terminated due to the incidence of FVIII inhibitors. The occurrence of inhibitors at two dose levels suggests that their development may be related to the subcutaneous route of administration. [ABSTRACT FROM AUTHOR]

Introduction: Patients with hemophilia A treated with coagulation Factor VIII (FVIII) products are at risk for developing anti‐FVIII antibodies. The ABIRISK Consortium aimed to provide knowledge on the formation and detection of anti‐drug antibodies against biopharmaceutical products, including FVIII. Accordingly, standardized and validated assays for the detection of binding (total) and neutralizing antibodies are needed. Aim: Two‐center validation of an ELISA for the detection of total FVIII‐binding IgG‐antibodies and Nijmegen‐Bethesda assays for the quantification of FVIII‐neutralizing antibodies according to consensus validation guidelines. Methods: Validation of assays at both sites was done according to published recommendations and included preanalytics, the determination of key assay parameters, including cut‐points, assay sensitivity, precision, and FVIII interference. Results: The validated assays reproducibly detected FVIII‐binding and ‐neutralizing antibodies with comparable performance in both laboratories. Floating screening cut‐points were established for both assays. Determined mass‐based sensitivity of both assays (all values ≤66 ng/mL) complied with the minimum sensitivity for the detection of anti‐drug antibodies as recommended by the FDA (<100 ng/mL). Intra‐ and inter‐assay coefficients of variation did not exceed 25%. Assay validation further revealed that pre‐analytical heat treatment led to potentially false‐positive ELISA results, while up to 0.15 IU/mL, residual FVIII showed no significant impact. Overall, good agreement of results was found for patient samples analyzed at both study sites. Conclusion: Comprehensive validation of different anti‐FVIII‐antibody assays in two laboratories gave novel insights into the impact of pre‐analytical sample treatment as well as the comparability of test results generated by the use of methodically different assays. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Introduction: Several well‐established clinical laboratory methods are available to measure von Willebrand factor (VWF) in plasma samples, but few data are available on their use for analysing recombinant VWF (rVWF). Aim: To evaluate how clinical diagnostic laboratories analyse rVWF and plasma‐derived VWF (pdVWF) spiked in vitro into VWF‐deficient plasma using quantitative protein and functional assays of VWF. Methods: Human VWF‐deficient plasma samples were spiked with rVWF (vonicog alfa; Takeda) or pdVWF/factor VIII (pdVWF/FVIII; antihemophilic factor/VWF complex [human], CSL Behring), each at final concentrations of 1.0, 0.6, 0.2, 0.1 IU/mL VWF:ristocetin cofactor activity (VWF:RCo) according to labelled VWF activity. The ISTH SSC secondary coagulation standard was used as a control. Participating laboratories received three sets of these blinded aliquots. Mean results per assay were compared with the expected potency based on the labelled VWF:RCo activity. Results: Among 39 laboratories, the most commonly established assay was VWF:RCo; 22 laboratories reported data from 2214 tests. Despite a trend to lower values, VWF:RCo activities for rVWF were in agreement with target concentrations (71%–109%), whereas VWF:platelet glycoprotein Ib (VWF:GpIb) and VWF collagen‐binding activity (VWF:CB) assays gave high recoveries (up to 132% and 127%, respectively). In contrast, pdVWF/FVIII was substantially underestimated by VWF:GpIb and VWF:CB assays (56%–86% recoveries), whereas the VWF:RCo assay gave recoveries of 47%–112% for pdVWF/FVIII. Conclusion: The results of VWF assays used in clinical laboratories differ between rVWF and pdVWF, particularly for VWF:GpIb and VWF:CB assays. These differences may arise from the higher multimeric structure of rVWF compared to pdVWF. [ABSTRACT FROM AUTHOR]

Introduction: The genetic variant responsible for haemophilia A (HA) significantly impacts endogenous coagulant factor VIII (FVIII:C) level, thus impacting DDAVP responsiveness. Blood group (BG) also impacts FVIII:C levels, but this is difficult to evaluate in a genetically heterogeneous population. Canada has a large cohort of mild‐moderate HA due to a single point variant: c.6104T>C, p.Val2035Ala—the Twillingate variant. Aim: To evaluate the impact of BG on endogenous FVIII:C levels and DDAVP responsiveness in a single genotype of mild‐moderate HA. Methods: This was a retrospective, single‐centre study. BG and FVIII:C levels were obtained for males with the Twillingate variant. One‐hour absolute and fold increases in FVIII:C post‐DDAVP were calculated. T‐tests and Mann–Whitney U tests were used to compare FVIII:C levels and DDAVP challenge variables between individuals according to BGs (O vs. non‐O). Results: Twenty males were included. There were significant differences between BGs (O vs. non‐O) in their lowest FVIII:C level at age <12 years (medians: 0.05 vs. 0.08 IU/mL; P =.05). Fifteen subjects underwent DDAVP challenges. Mean 1‐h FVIII:C were 0.29 (O BG) versus 0.41 IU/mL (non‐O BG); P =.04. There were no significant differences between BGs (O vs. non‐O) in mean absolute FVIII:C increase (0.20 vs. 0.27 IU/mL; P =.10) and FVIII:C fold increase (3.3‐fold vs. 3.8‐fold; P =.51). Conclusion: In HA subjects with an identical genotype, BG significantly impacts baseline FVIII:C levels and FVIII:C levels post‐DDAVP, but does not impact absolute and fold increases in FVIII:C with DDAVP. [ABSTRACT FROM AUTHOR]

Key Clinical Message: Acquired hemophilia A (AHA) can present as life‐threatening bleeding during the postpartum period. Prompt treatment allows patients with AHA to achieve complete remission and have normal subsequent pregnancies. Acquired hemophilia A (AHA) is a rare bleeding disorder caused by the production of autoantibodies against factor VIII (FVIII). AHA can present with severe bleeding, especially in postpartum patient. We report a 38‐year‐old woman who presented in an emergency department with severe postpartum hemorrhage 2 weeks after cesarean section. Her investigation showed an isolated prolongation of partial thromboplastin time (PTT), low factor VIII assay and a factor VIII inhibitor test, resulting in abnormal Bethesda units which consistent with AHA. This case report highlights the importance of early diagnosis and treatment of AHA. With timely and appropriate management, most patients can achieve a good outcome. [ABSTRACT FROM AUTHOR]

Background: Prophylaxis with a von Willebrand factor (VWF) concentrate is recommended in von Willebrand disease (VWD) patients with a history of frequent and severe bleeds. Despite nosebleeds being a frequent manifestation of VWD, few studies have investigated the efficacy of factor prophylaxis in preventing nosebleeds in patients with severe VWD. Methods: This post-hoc analysis of a prospective, 12-month, phase 3 study assessed the efficacy of wilate in the prevention of nosebleeds in 33 patients aged ≥6 years with severe type 1, type 2 or type 3 VWD. All patients previously participated in a 6-month prospective study of on-demand treatment with any VWF concentrate. Prophylactic efficacy was assessed by comparing total and spontaneous annualized bleeding rates for nosebleeds (TABR and SABR, respectively) during prophylaxis with rates during on-demand treatment. Results: The mean TABR and SABR for nosebleeds were reduced by 76% and 81% respectively during prophylaxis versus on-demand treatment (2.7 vs 11.0 and 2.1 vs 10.9). During the second 6 months of prophylaxis, mean TABR was 49% lower and mean SABR 57% lower versus the first 6 months. The percentage of patients with zero nosebleeds was 19% during 6 months of on-demand treatment, 55% during the first 6 months of prophylaxis, and 68% during the second 6 months of prophylaxis. The efficacy of wilate in the treatment of breakthrough nosebleeds was rated excellent in 99% of cases. Conclusion: This post-hoc analysis demonstrated the efficacy of wilate prophylaxis in the prevention and treatment of nosebleeds in children and adults with severe VWD. [ABSTRACT FROM AUTHOR]

Prophylaxis is the gold standard for the management of hemophilia A patients. It has been shown that prophylaxis regulated with pharmacokinetic (PK) data reduces frequency of bleeding and cost of treatment. To determine the best prophylaxis regimen, PK dosing tools using the Bayesian method have been developed. We aimed to compare two PK dosing tools. Blood samples were drawn before, 4, 24, and 48 h after FVIII infusions from patients with severe hemophilia A and inhibitor negative. FVIII levels were measured by PTT-based one-stage assay method. PK parameters obtained using WAPPS and myPKFiT, which are web-accessible PK dosing tools using Bayesian algorithm, and daily prophylaxis dose estimated by the programs were compared. Forty-two hemophilia A patients [median age 13 years (IQR 8.9–16.4)] included in the study. There was no difference between the daily dose of FVIII given for prophylaxis and the dose recommended by the myPKFiT for the 1% trough level; whereas, a significant difference was found with the WAPPS. The half-lives of FVIII did not differ between the two dosing tools; however, significant differences were found in the estimated dose, clearances, and times to 1% trough level. There was no significant difference between PK data of patients who received Advate® and those who received non-Advate® factor concentrates. Choice of PK dosing tool can affect recommended FVIII dose. However, target trough levels should be individualized according to bleeding phenotype and daily activity of patient. [ABSTRACT FROM AUTHOR]

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Background: Von Willebrand factor (VWF) and factor VIII (FVIII) complex play a pivotal role in hemostasis. A deficiency or defect of VWF causes von Willebrand disease (VWD). Recombinant (r)VWF product has proved to be effective for hemostatic treatment of VWD, but limited information is available on their role in moderating thrombus formation under flow condition. We aimed to assess thrombus formation in the presence of rVWF combined with rFVIII or pegylated-extended half-life rFVIII (peg-EHL-rFVIII) in VWD whole blood under high shear flow. Methods: Perfusion chamber experiments under high shear (2,500 s− 1) combined with immunostaining were performed using patient's whole blood with type 1 VWD, mixed with rVWF (Vonvendi®; 1.6 IU/mL), rFVIII or peg-EHL-rFVIII (Advate® or Adynovate®; 1.0 IU/mL), or both. Similar experiments were also conducted with clinical medical devices (T-TAS®). Results: The addition of rFVIII did not augment thrombus formation assessed by surface coverage (SC) and thrombus height (TH), whereas rVWF enhanced these parameters (SC 19.1 ± 1.1% vs. 30.1 ± 4.1%, TH 2.2 ± 0.14 μm vs. 3.6 ± 0.40 μm, respectively). The co-presence of rVWF/rFVIII was comparable to plasma-derived VWF/FVIII (Confact®, VWF:FVIII ratio = 1.6:1.0) for increasing thrombogenicity in SC (32.5 ± 4.3% vs. 38.7 ± 5.5%) and in TH (5.0 ± 0.60 μm vs. 5.5 ± 0.64 μm), respectively. The pre-incubation time with rVWF and rFVIII appeared to have a little effect on the size of thrombus. Peg-EHL-rFVIII mediated thrombus formation to similar extent as rFVIII in the co-presence of rVWF. Similar results were obtained even with T-TAS. Immunostaining demonstrated that rFVIII and peg-EHL-rFVIII were similarly co-localized with rVWF in formed thrombi, indicating that pegylation did not interfere with molecular complexes. Conclusion: The effects of high-level rVWF and peg-EHL-rFVIII on thrombus formation were comparable to conventional therapeutic products in a patient's whole blood with VWD under high shear flow. [ABSTRACT FROM AUTHOR]

To report the long-term prophylaxis management of a child with type 3 von Willebrand disease by switching to Wilate (Octapharma AG), a plasma-derived, double virus-inactivated concentrate of freeze-dried of a 1 to 1 ratio of active Von Willebrand Factor and Factor VIII (pdVWF:pdFVIII) recently marketed as Eqwilate in France. This is a case report of 12.6-year-old boy with congenital Type 3 VWD who had a history of frequent bleeds. Prophylaxis started at the age of 38 months with FVIII-poor pdVWF concentrate (Wilfactin, LFB) and FVIII (Wilstart, LFB). Pharmacokinetics and thrombin generation assay were performed. Annualized bleeding rate was derived from the bleeding episodes documented in the medical record during a 24-month period before and after starting pdVWF:pdFVIII concentrate. Both product injections promptly raised the endogenous thrombin potential (ETP). However, the maximal concentration of formed thrombin was higher following pdVWF:pdFVIII injection. Due to a high bleeds frequency and better results regarding FVIII levels and thrombin generation, the prophylaxis regimen was changed to the same dose and frequency of pdVWF:pdFVIII concentrate (42 IU/kg per day, three times a week). During the last 24 months, annualized total, trauma, and spontaneous bleeding rates were 7.5, 4.5, and 3, respectively. These rates decreased to 2, 1.5, and 0.5 respectively during the next two years. The mother reported a marked improvement in the quality of life of his son and hers. Switch to pdVWF:pdFVIII concentrate for long-term prophylaxis in a young type 3 VWD patient was safe and effective in reducing bleeds. [ABSTRACT FROM AUTHOR]

As the most commonly used coagulation factor VIII (FVIII) concentrate in China, the individualized dosing prediction model of Kovaltry (BAY81–8973) is not fully investigated in pediatric patients. The prophylaxis tailored by population pharmacokinetic (PopPK) model can optimize dosing regimens. This study aimed to develop PopPK models of BAY 81–8973 in pediatric patients, identify quantitative relationships of blood type (as a substitution for von Willebrand factor) on FVIII clearance and provide model-informed precision dosing (MIPD) procedures. Pediatric patients with severe hemophilia A were enrolled and PK tests were conducted. The blood samples were collected at six time point. One-stage-based activated partial thromboplastin time was used for FVIII activity. Basic demographics and key covariates (blood type and von Willebrand factor antigen) were collected. A nonlinear mixed-effect modeling (NONMEM) approach was employed to establish PopPK model. Simulations were performed to evaluate current dosing regimens and present MIPD strategies. A total of 30 pediatric patients were included in the analysis. In the final model, Fat-free mass calculated from weight, age, and height was included as a size descriptor which affect FVIII apparent volume of distribution and clearance. Both von Willebrand factor antigen (VWF:Ag) and blood type accounted for the interindividual variability of FVIII clearance, but only one can retain in the final model. Therefore, two PopPK models based on VWF:Ag or blood type were developed. When the VWF:Ag value is doubled, the FVIII clearance is reduced by 35 %. Compared with blood type non-O, the clearance in pediatric patients with blood type O increased by 25.9 %. Weight-based dosing without regard to age and blood type resulted in large differences in FVIII trough activity. Patient demographics, dosing information, sparse blood samples and PopPK model together with Bayesian estimate constituted the MIPD workflow. Using it, the individual parameters and optimized dosing regimen could be achieved. This is the first predictive model designed to predict individualized dosing of BAY 81–8973 in pediatric patients with Hemophilia A. These results are useful in the PK-guided prophylaxis among pediatric patients and hold great potential to improve their long-term clinical outcomes. [Display omitted] • Two population PK models of FVIII concentrate BAY 81-8973 in pediatric patients were developed for the first time. • Both von Willebrand factor antigen (VWF:Ag) and blood type accounted for the interindividual variability of FVIII clearance. • VWF:Ag can explain 5.8% of interindividual variability in clearance more than blood type. • Blood type can act as a substitute for VWF:Ag and the CL with blood type O increased by 25.9% compared with blood type non-O. • The models hold great potential to improve long-term clinical outcomes by predicting individualized dosing of FVIII. [ABSTRACT FROM AUTHOR]

Prophylactic treatment with emicizumab has become an important and effective bleeding prevention for people with hemophilia A (PwHA). Perioperative management of PwHA using emicizumab prophylaxis is still challenging due to a lack of experience. Medical records of perioperative management and outcomes were reviewed, and data were collected for adult PwHA receiving emicizumab and undergoing surgical procedures between August 2019 and July 2022 at the University Medical Center Ljubljana. Twelve surgical procedures were performed in eight PwHA (one with FVIII inhibitors) while on emicizumab prophylaxis. Three minor procedures included cataract surgery, cystoscopic lithotripsy, and percutaneous coronary intervention. Nine major surgeries included four osteosyntheses, necrectomy of chronic osteomyelitis with new ankle arthrodesis, two below-knee amputations, total knee replacement, and placement of ventriculostomy after a spontaneous intraventricular hemorrhage. No major bleeds, thrombotic events or deaths, or new inhibitors appeared. Our real-world experience demonstrates that minor and major surgeries can be performed safely in PwHA on emicizumab prophylaxis. Additional data are needed to optimize dosing/duration of additional hemostatic agents in diverse invasive procedures and complex clinical situations. [ABSTRACT FROM AUTHOR]

This paper presents a portable point-of-care testing (POCT) device to conduct simultaneous and on-site tests of ABO and Rh(D) forward blood typing and hemophilia diagnosis using only a small amount of human whole blood sample. The POCT device consisted of a spinning module, a measuring circuit, an interdigitated electrode (IDE) for hemophilia diagnosis, and three disposable microfluidic chips for bioassays with anti-A, anti-B, and anti-D, respectively, and measurement of the concentration of factor VIII. Agglutination will occur if red blood cells (RBCs) are exposed to the corresponding antibody. To evaluate the degree of RBC agglutination, a linear sweep voltage, ranging from − 0.5 to + 0.5 V, was applied to the electrodes of the microfluidic chip and the resulting current was measured. For different levels of agglutination, the measured I–V curves were explicitly discriminated, providing five clinical levels from non-agglutination (level 0) to strong agglutination (level 4). The quantitative norm obtained from cubic fitting function of each I–V curve served as the criterion to represent this agglutination level. The ABO blood type was determined by both agglutination levels of the blood sample reacting with anti-A and anti-B. The degree of agglutination with anti-D gave the Rh(D) type. Moreover, the concentration of factor VIII was detected for the determination of hemophilia. Without requiring expensive equipment, this POCT device is especially suitable for usage in emergency or natural disasters to provide quantitative testing in rescue and relief operations. [ABSTRACT FROM AUTHOR]

Emicizumab prophylaxis dramatically reduces bleeding events in patients with hemophilia A (PwHA) with or without factor VIII (FVIII) inhibitors. However, long-term dynamic changes in FVIII inhibitor titers during emicizumab prophylaxis remain to be investigated. We conducted a retrospective follow-up study of FVIII inhibitor titers after initiation of emicizumab prophylaxis in 25 PwHA carrying current or historical FVIII inhibitors. Nineteen PwHA had FVIII inhibitors at initiation of emicizumab prophylaxis (age: median 22 [range 4–60] years and inhibitor titer: 30 [1.0–1450] BU/mL). In 17 of the 19 patients, the inhibitor titers markedly decreased to a median of 1.2 (< 0.6–58) BU/mL at a median follow-up of 71 (38–111) months. In two patients, titers were slightly elevated after initiation of emicizumab but decreased in the long term. The remaining six patients had negative inhibitor status (< 0.6 BU/mL) when switched to emicizumab from FVIII prophylaxis. Five patients maintained negative titers. One patient had inhibitor recurrence, with a peak titer of 1.6 BU/mL that decreased to 0.9 BU/mL. In most cases, FVIII inhibitor titers can be expected to decrease spontaneously during emicizumab prophylaxis, but regular follow-up is necessary to manage breakthrough bleeds. [ABSTRACT FROM AUTHOR]

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Objective To investigate the possible molecular pathogenesis of a child with hemophilia A accompanied by coagulation factor Ⅺ reduction by testing coagulation-related indicators and genotyping in the child and his family. Methods Peripheral blood from the patient and his parents for detection of coagulation factors Ⅷ, Ⅸ, Ⅺ, Ⅻ, VWF∶Ag, lupus anticoagulants and F VIII, F XI inhibitors were collected. All exons and flanking sequences of the genes encoding FⅧ and FⅪ were sequenced and bioinformatically analyzed. Results The child had low FⅧ and FⅪ activity and no parental abnormalities were observed. The sequencing results showed that there was a c. 1834(exon12) C>T heterozygous mutation in the FⅧ gene and a c. 1817 (exon15) G>A heterozygous mutation in the FⅪ gene, which was de novo. Bioinformatics analysis shows that the FⅪ mutation changes the original protein structure and increases the number of carboxyl groups. Conclusion For patients with prolonged APTT, in addition to excluding factors that interfere with APTT testing, all coagulation factors related to APTT should be tested to clarify the diagnosis.

ObjectiveTo test the hypothesis that factor eight inhibitor bypassing activity (FEIBA) can be used to control bleeding following left ventricular assist device (LVAD) implantation without increasing the 14-day composite thrombotic outcome of pump thrombus, ischemic cerebrovascular accidents, pulmonary embolism, and deep venous thrombosis.DesignRetrospective cohort study.SettingAcademic hospital.ParticipantsThree hundred nineteen consecutive patients who underwent LVAD implantation (December 1, 2009 to December 30, 2018).InterventionFEIBA administered to control perioperative hemorrhage.Measurements and main resultsThe 82 patients (25.7%) in the FEIBA cohort had more risk factors for perioperative hemorrhage, such as lower preoperative platelet count (169 ± 66 v 194 ± 68 × 103/mL, p = 0.004), prior cardiac surgery (36.6% v 21.9%, p = 0.008), and longer cardiopulmonary bypass (CPB) time (100.3 v 75.2 minutes, p = 0.001) than the 237 controls. After 16.6 units (95% CI: 14.3-18.9) of blood products were given, 992 units (95% CI: 821-1163) of FEIBA were required to control bleeding in the FEIBA cohort. Compared to the controls, there were no differences in the 14-day composite thrombotic outcome (11.0% v 7.6%, p = 0.343) or mortality rate (3.7% v 1.3%, p = 0.179). Multivariate logistical regression identified preoperative international normalized ratio (odds ratio [OR]: 1.30, 95% CI: 1.04-1.62) and CPB time (OR: 1.11, 95% CI: 1.02-1.20) as risk factors for 14-day thrombotic events, but FEIBA usage was not associated with an increased risk.ConclusionsIn this retrospective cohort study, the use of FEIBA (∼1,000 units, ∼13 units/kg) to control perioperative hemorrhage following LVAD implantation was not associated with increases in mortality or composite thrombotic outcome.

Abstract Background Haemophilia A carries a substantial healthcare burden, affecting health-related quality of life (HRQoL). The Cost of Haemophilia in Men: a Socioeconomic Survey II (CHESS II), a retrospective real-world study, characterised the burden of haemophilia and its impact on HRQoL and work productivity. The current analysis explored the impact of bleeding events on HRQoL and work productivity in Europe. This analysis focused on data collected from males aged 18 to 64 years with haemophilia A without inhibitors who were receiving replacement factor products or a monoclonal antibody and were not participating in a clinical trial at the time of study recruitment. Descriptive statistics were analysed using scores from EuroQoL’s EQ-5D-5L index and EQ-VAS analogue scale and the Work Productivity and Activity Index Specific Health Problem (WPAI:SHP) percentage scores stratified by the number of annual bleeding events (ABs) 0, 1, 2, 3–4, or ≥ 5. Results Of 918 males with haemophilia A in CHESS II, 318 met inclusion criteria and had data available for HRQoL measures; mean age (SD) was 33.8 (12.1) years and 96% were White. Mean (SD) ABs of 2.7 (2.9) occurred over the preceding 12 months: 20% had 3 or 4 ABs; 17% had ≥ 5 ABs. Mean EQ-5D-5L index scores for patients with 0, 1, 2, 3–4, or ≥ 5 ABs were 0.92, 0.76, 0.76, 0.71, and 0.56, respectively. Mean (SD) EQ-VAS scores were 86.9 (13.6), with 0 ABs versus 69.5 (19.1) for 3 or 4 ABs and 61.2 (17.2) for ≥ 5 ABs. Mean percentage of overall work productivity loss on the WPAI:SHP questionnaire ranged from 9.70 to 0 ABs to 47.65 for ≥ 5 ABs. Conclusions In this European sample of adult men with haemophilia A, HRQoL and work productivity scores were lower among those reporting more AB events. Bleeding burden appears to affect HRQoL and productivity; however, this cross-sectional analysis limits the ability to draw firm conclusions on causality.

Objective: Hemophilia A is an X-linked recessive bleeding disorder caused by a deficiency of plasma coagulation factor VIII (FVIII), and it accounts for about 80%-85% of all cases of hemophilia. Plasma-derived therapies or recombinant FVIII concentrates are used to prevent and treat the bleeding symptoms along with FVIIImimicking antibodies. Recently, the European Medicines Agency granted conditional marketing approval for the first gene therapy for hemophilia A. The aim of this study was to determine the effectiveness of coagulation in correcting FVIII deficiency with FVIII-secreting transgenic mesenchymal stem cells (MSCs). Materials and Methods: A lentiviral vector encoding a B domaindeleted FVIII cDNA sequence with CD45R0 truncated (CD45R0t) surface marker was designed to develop a transgenic FVIII-expressing primary cell line by transducing MSCs. The efficacy and functionality of the FVIII secreted from the MSCs was assessed with anti-FVIII ELISA, CD45R0t flow cytometry, FVIII western blot, and mixing test analysis in vitro. Results: The findings of this study showed that the transgenic MSCs maintained persistent FVIII secretion. There was no significant difference in FVIII secretion over time, suggesting stable FVIII expression from the MSCs. The functionality of the FVIII protein secreted in the MSC supernatant was demonstrated by applying a mixing test in coagulation analysis. In the mixing test analysis, FVIIIdeficient human plasma products were mixed with either a saline control or FVIII-secreted MSC supernatant. The mean FVIII level of the saline control group was 0.41±0.03 IU/dL, whereas the mean level was 25.41±33.38 IU/dL in the FVIII-secreting MSC supernatant mixed group (p

Abstract Background Hemophilia A (HA) is an X-linked monogenic disorder caused by deficiency of the factor VIII (FVIII) gene in the intrinsic coagulation cascade. The current protein replacement therapy (PRT) of HA has many limitations including short term effectiveness, high cost, and life-time treatment requirement. Gene therapy has become a promising treatment for HA. Orthotopic functional FVIII biosynthesis is critical to its coagulation activities. Methods To investigate targeted FVIII expression, we developed a series of advanced lentiviral vectors (LVs) carrying either a universal promoter (EF1α) or a variety of tissue-specific promoters, including endothelial-specific (VEC), endothelial and epithelial-specific (KDR), and megakaryocyte-specific (Gp and ITGA) promoters. Results To examine tissue specificity, the expression of a B-domain deleted human F8 (F8BDD) gene was tested in human endothelial and megakaryocytic cell lines. Functional assays demonstrated FVIII activities of LV-VEC-F8BDD and LV-ITGA-F8BDD in the therapeutic range in transduced endothelial and megakaryocytic cells, respectively. In F8 knockout mice (F8 KO mice, F8 null mice), intravenous (iv) injection of LVs illustrated different degrees of phenotypic correction as well as anti-FVIII immune response for the different vectors. The iv delivery of LV-VEC-F8BDD and LV-Gp-F8BDD achieved 80% and 15% therapeutic FVIII activities over 180 days, respectively. Different from the other LV constructs, the LV-VEC-F8BDD displayed a low FVIII inhibitory response in the treated F8 null mice. Conclusions The LV-VEC-F8BDD exhibited high LV packaging and delivery efficiencies, with endothelial specificity and low immunogenicity in the F8 null mice, thus has a great potential for clinical applications.

Alexander Bauer,1 Sofia Friberg-Hietala,2 Giovanni Smania,2 Martin Wolfsegger1 1Statistical and Quantitative Sciences, Baxalta Innovations GmbH, a Takeda Company, Vienna, Austria; 2Pharmetheus AB, Uppsala, SwedenCorrespondence: Alexander Bauer, Baxalta Innovations GmbH, a Takeda company, Donau-City-Straße 7, Vienna, A-1220, Austria, Tel +43 1 201002472997, Email alexander.bauer@takeda.comBackground: Recombinant von Willebrand factor (rVWF, vonicog alfa, Vonvendi/Veyvondi, Takeda Pharmaceuticals USA, Lexington, MA) and several plasma-derived VWF/factor VIII (pdVWF/FVIII) concentrates are available for treating bleeding episodes in patients with von Willebrand disease (VWD).Purpose: To develop population pharmacokinetic (PK)/pharmacodynamic (PD) models that describe VWF:ristocetin cofactor (VWF:RCo) activity and its relationship with FVIII activity (FVIII:C) over time following intravenous administration of either rVWF or a pdVWF/FVIII concentrate (VWF:RCo/FVIII:C 2.4:1) in patients with VWD; to use the final PK/PD models for an in silico comparison of rVWF and pdVWF/FVIII.Methods: The population PK model for rVWF was based on data from four clinical studies in which rVWF was administered to adult patients with VWD type 1, 2 or 3 (phase 1: NCT00816660; phase 3: NCT01410227 and NCT02283268) or severe hemophilia A (phase 1: EudraCT 2011– 004314-42). The PK and PK/PD models for pdVWF/FVIII were based on data from the phase 1 study (NCT00816660) in patients with type 3 VWD who received either rVWF plus recombinant FVIII (rFVIII, octocog alfa, ADVATE®, Takeda Pharmaceuticals USA, Lexington, MA, USA) or pdVWF/FVIII.Results: There was a marked difference in clearance following rVWF administration compared with pdVWF/FVIII in type 3 VWD, leading to a ~1.75 longer mean residence time (ie, persistence of VWF:RCo activity in the body) and half-life for rVWF versus pdVWF/FVIII. Simulations showed that following repeated administration of rVWF (50 IU/kg), a FVIII:C activity of > 40 IU/dL can be maintained for the full 72 h dosing interval.Conclusion: The slower elimination of VWF:RCo following rVWF administration results in a prolonged effect on FVIII turnover compared with pdVWF/FVIII administration.Keywords: factor VIII, pharmacodynamics, pharmacokinetics, plasma-derived, recombinant, von Willebrand factor

BACKGROUND: Standard of care for bleed prevention in patients with severe congenital hemophilia A is continuous prophylaxis with factor VIII (FVIII), typically administered intravenously 2-3 times per week in the home setting. Nonfactor prophylaxis and gene therapy are emerging novel prophylaxis strategies for hemophilia A, and it is important to compare their health economics with that of FVIII prophylaxis. Current data on resource utilization and costs in the adult hemophilia A prophylaxis population are limited, and a structured approach to analyze annual costs in these patients using administrative claims data has not been previously reported. OBJECTIVE: To assess health care resource utilization and costs of continuous FVIII prophylaxis in commercially insured adults with hemophilia A without inhibitors. METHODS: Administrative claims records from beneficiaries covered by major selfinsured companies in the United States from January 1999 through March 2017 (OptumHealth Care Solutions) were queried, and records for adult patients (aged 18-64 years) diagnosed with hemophilia A who received FVIII were extracted. Three criteria were defined to distinguish patients most likely to be managed with continuous FVIII prophylaxis from those on episodic treatment based on the frequency and timing of FVIII claims over a 12-month period of continuous enrollment: (1) having ≥ 4 FVIII claims, (2) having ≥ 6 FVIII claims, or (3) having no gaps > 60 days between FVIII claims. Patients with evidence of bypassing agent use were excluded. Health care resource utilization and costs were assessed for all patients with any FVIII use and for patients defined as being managed with continuous FVIII prophylaxis based on each criterion. RESULTS: The analysis included 189 patients with a diagnosis code for hemophilia A (ICD 9-CM code 286.0; ICD-10-CM code D66) from January 1999 through March 2017 who had at least 12 months of continuous enrollment and at least 1 noninpatient/nonemergency department claim for FVIII concentrate (any type) during their last 12 months of continuous enrollment (overall cohort). Within the overall cohort, 118, 94, and 61 patients met the criteria for FVIII prophylaxis based on the first, second, and third definitions, respectively. Per patient mean (SD) total health care costs for the overall cohort was $287,055 (306,933). For patients meeting criteria 1 through 3, per patient costs ranged from $407,752 (321,036) to $551,645 (302,841). FVIII concentrate accounted for over 90% of costs, with mean (SD) annual FVIII costs of $264,777 (292,423) in the overall cohort and $384,197 (303,826), $433,029 (313,711), and $531,098 (297,142) among patients meeting the respective definitions for prophylaxis. CONCLUSIONS: This analysis highlights the substantial economic burden associated with managing adults with hemophilia A on FVIII prophylaxis, where per patient mean total annual health care costs ranged from $407,752 to $551,645. Over 90% of such costs were attributable to FVIII concentrate dispensed. DISCLOSURES: This study was funded by BioMarin Pharmaceutical, which was involved in protocol development, analysis plan development, data interpretation, manuscript preparation, and publication decisions. All authors contributed to protocol development, analysis plan development, data interpretation, and manuscript development. All authors maintained control over the final content. Sammon, Solari, Kim, and Hinds are employees and shareholders of BioMarin Pharmaceutical. Cook, Sheikh, and Chawla are employees of Analysis Group, a consulting company that was contracted by BioMarin Pharmaceutical to conduct this study and develop the manuscript. Croteau has received professional fees from BioMarin Pharmaceutical, Bayer, CSL Behring, Genentech, and Pfizer. Thornberg has received professional fees from BioMarin Pharmaceutical, Genentech, Novo Nordisk, Sanofi, and Spark Therapeutics, as well as research funding from Novo Nordisk and Sanofi.

ObjectiveTo compare the efficacy of fresh frozen plasma (FFP) with cryopoor plasma (CPP) to treat vitamin K-dependent factor deficiency in a canine in vitro setting.DesignIn vitro laboratory study.SettingUniversity veterinary medical teaching hospital.AnimalsSeven units of FFP and 6 units of CPP from unique canine donors from the university veterinary blood bank.InterventionsCanine FFP was adsorbed by oral barium sulfate suspension to mimic vitamin K-dependent coagulopathy. A sequential mixing study was completed by adding FPP or CPP to the adsorbed plasma. Measurements of prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen, and factor activities of factors II, VII, and IX (FII, FVII, and FIX) were compared between the 2 treatment groups.Measurements and main resultsWhen comparing the sequential addition of CPP or FPP to adsorbed plasma, the following had no statistical significance: PT (P = 0.94), aPTT (P = 0.66), FII (P = 0.05), and FIX (P = 0.90). There was a dose-dependent decrease with PT and aPTT and a dose-dependent increase with FII and FIX. In contrast, after the addition of either CPP or FFP, there was a significant difference between the treatment groups for the concentration of fibrinogen (P = 0.005) and activity of FVII (P = 0.044), with FFP resulting in a greater concentration of fibrinogen and CPP resulting in a greater concentration of FVII. Measurements of factor X (FX) were initially included in the study but were later excluded because FX appeared to be continually adsorbed even after the addition of CPP or FFP.ConclusionsCPP partially corrected the coagulation times and concentration of vitamin K-dependent coagulation factors to the same degree as FFP. CPP, generally less expensive than FFP, may provide an alternative treatment option for vitamin K-dependent coagulopathies, although in vivo testing is needed.

Up to 30 % of COVID-infected patients may develop post-acute sequelae of COVID-19 (PASC), also known as Long COVID (LC), a syndrome characterized by a variety of debilitating symptoms lasting for more than 3 months after the acute infection. While the pathophysiological mechanisms behind PASC/LC are not completely understood, growing evidence suggests that an important component of this syndrome may be related to persistent microvascular inflammation causing clumping/clotting of red blood cells and platelets and thrombotic complications. We retrospectively evaluated the plasma levels of von Willebrand factor (VWF), Factor VIII and D-dimer in 10 gynecologic patients (60 % with an endometrial or ovarian cancer diagnosis) affected by PASC/LC vs 5 control patients (60 % harboring endometrial or ovarian tumors). We found elevated VWF and Factor VIII levels in all 10 PASC/LC patients (means of 254 % and 229 %, respectively) vs none of the 5 randomly selected cancer control patients (means of 108 % and 95 %, respectively), p = 0.0046 and p