Factor VIII and Factor IX Activity Measurements for Hemophilia Diagnosis and Related Treatments

Using machine learning to predict Hemophilia A severity

Hemophilia A is a rare genetic condition that predominantly affects men and is characterized by a deficiency in Factor VIII clotting (FVIII). This research focuses on the development of a classification model to predict the severity of Hemophilia A, using data from point mutations in the FVIII protein. The study employs a variety of classification models, including RandomForest, XGBoost, and LightGBM, and performs a robust analysis of the data to select the most relevant features. The final model achieved an accuracy of 65.5 %, demonstrating significant performance against a simple gaussian naive bayes model that achieves 51.1 % of accuracy. Although the model cannot yet replace the FVIII measurement test in the blood for diagnostic purposes, the results represent a significant advance in Hemophilia A research. This work provides data analysis that deepens the understanding of the characteristics of the FVIII protein and contributes to the development of models capable of classifying the severity of this condition into its three possible classes: mild, moderate, or severe.

Haemophilia

Haemophilia A and B are congenital X-linked bleeding disorders resulting from deficiencies in clotting factors VIII (haemophilia A) and IX (haemophilia B). Patients with severe deficiency, defined as having less than 1% of normal plasma factor activivity, often have spontaneous bleeding within the first few years of life. Those with moderate and mild deficiencies typically present with post-traumatic or post-surgical bleeding later in life. A high index of suspicion and measurement of factor activity in plasma facilitates early diagnosis. In the 21st century, therapeutic advances and comprehensive care have substantially improved both mortality and morbidity associated with these conditions. Management strategies for haemophilia include on-demand treatment for bleeding episodes and all surgeries and regular treatment (ie, prophylaxis) aimed at reducing bleeds, morbidity, and mortality, thereby enhancing quality of life. Treatment options include factor replacement therapy, non-replacement therapies that increase thrombin generation, and gene therapies that facilitate in vivo clotting factor synthesis. The therapies differ in their use for prophylaxis and on-demand treatment, the mode and frequency of administration, duration of treatment effect, degree of haemostatic protection, and side-effects. Monitoring the effectiveness of these prophylactic therapies involves assessing annual bleeding rates and joint damage. Personalised management strategies, which align treatment with individual goals (eg, playing competitive sports), initiated at diagnosis and maintained throughout the lifespan, are crucial for optimal outcomes. These strategies are facilitated by a multidisciplinary team and supported by clinician-led education for both clinicians and patients.

Quality-of-Life Assessment and Pharmacokinetic Study in Hemophilia A Patients Undergoing Prophylactic Treatment

This study evaluates the health-related quality of life (HRQoL) among patients with hemophilia A currently undergoing prophylactic treatment at the Hemophilia Center of Northern Greece. Using the Haem-A-QoL questionnaire, we assessed various HRQoL dimensions in a cohort of 29 adult male patients, analyzing the impact of age, disease severity, and treatment regimens. The results revealed that younger patients (18-30 years old) exhibited significantly better overall HRQoL scores (total score of 25.36) compared to older age groups (37.81 for the 31-45 group and 43.71 in the 45+ group), particularly in the physical health (29.16 vs. 48.43 vs. 58.57) and mental well-being domains (25 vs. 37.11 vs. 41.07). Interestingly, moderate hemophilia patients reported lower HRQoL (42.31) than those with severe form (34.85), suggesting unique challenges in managing their condition. The 'Sports/Free Time' domain had the highest scores (65.81), indicating significant limitations in physical activities in the everyday lives of affected individuals. However, better outcomes were observed in the mental dimension (36.09), work/study (34.88), family planning (10.68), and relationships aspects (16.67), where our cohort reported very low scores compared to similar studies, indicating a significantly better quality of life in these domains. These findings highlight the importance of personalized psychosocial support and targeted interventions to address the specific needs of hemophilia patients, particularly in enhancing physical activity opportunities and managing the psychological burden of moderate hemophilia. The study contributes valuable insights into the HRQoL of hemophilia patients and underscores the necessity for tailored approaches to improve patient outcomes across all dimensions of life.

Nonsevere Hemophilia: The Need for a Renewed Focus and Improved Outcomes

People with nonsevere hemophilia (PWNSH) are phenotypically more diverse than those with severe hemophilia. Perceptions relating to a "nonsevere" phenotype have contributed to fewer research initiatives, fewer guidelines on optimal management, and a lack of standards for surveillance and clinical assessment for affected individuals. In many cases, episodes of abnormal bleeding could, if investigated, have led to earlier diagnosis. Furthermore, the major recent developments in therapy for hemophilia have largely focused on severe disease and, as a group, PWNSH have not been included in many key clinical trials. Benefiting people with severe disease, innovative replacement therapies have generally targeted factor levels that are above those present in a large proportion of PWNSH. Therapeutic advances can lead to improvement in phenotype for people with severe hemophilia over that currently experienced by many PWNSH. As a result, we are approaching a point where PWNSH may, in many countries, have a higher risk of bleeding and restriction in lifestyle than those with severe disease but with more limited therapeutic options. Given the multiple major advances in treatment for people with hemophilia, it is timely to review the aspects of nonsevere disease, to ensure equity in care and management for all individuals with this condition.

Laboratory Assessment of Factor VIII Inhibitors: When Is It Required? A Perspective Informed by Local Practice

This perspective discusses the critical role of laboratory assessments in assessing factor VIII (FVIII) inhibitors. These are auto- and alloantibodies that can develop against both endogenous and exogenous FVIII, respectively. Assessment for inhibitors represents a key part of the management of both congenital hemophilia A (CHA), an inherited deficiency, and acquired hemophilia A (AHA), an autoimmune condition. Both conditions pose significant bleeding risks, necessitating careful monitoring of FVIII levels and inhibitor presence and level. Laboratory assays, particularly the Bethesda assay, are essential for detecting these inhibitors and assessing their levels. The complexities of FVIII inhibitor kinetics may pose challenges to interpretation of assay results, such that even normal FVIII levels do not always exclude inhibitor presence. Clinical practice guidelines recommend ongoing monitoring of AHA/CHA patients until inhibitors are no longer detectable. Overall, timely laboratory evaluations are essential to optimizing treatment strategies for patients with hemophilia, aiming to improve patient outcomes and quality of life. We summarize our approach to the laboratory assessment of FVIII inhibitors, as reflecting our perspective and as informed by local practice.

Innovative Diagnostic Solutions in Hemostasis

Hemostasis describes the process of blood clotting homeostasis. Hemostasis reflects a balance of procoagulant and anticoagulant mechanisms that aim to prevent both bleeding and thrombosis. If hemostasis is disrupted, and bleeding or thrombosis occur, then laboratory testing may ensue to either diagnose the reason for bleeding or thrombosis, or to manage patients under therapy or treatment for bleeding or thrombosis. A wide range of tests of hemostasis are available to laboratories and to clinicians, from routine coagulation assays to specialized hemostasis assays and platelet function. In the current narrative review, we highlight some of the history of innovative diagnostic solutions, such as the integration of chemiluminescence and flow cytometry in the hemostasis diagnostic armamentarium, as well as providing a glimpse to the possible future of diagnostic hemostasis testing. Future directions include the potential for artificial intelligence in diagnostics, the development of more global test systems that can assess both primary and secondary hemostasis, and several innovations to enable the ongoing evolution of therapies to rebalance hemostasis and requiring precise monitoring. This review underscores the ongoing need for innovation to enhance the diagnostic landscape of hemostasis, ensuring better patient outcomes through more accurate and efficient diagnostic methods.

Detection of hemophilia A genetic variants using third-generation long-read sequencing

BACKGROUND

Hemophilia A (HA) is an X-linked recessive genetic disorder caused by pathogenic variations of the factor VIII -encoding gene, F8 gene. Due to the large size and diverse types of variations in the F8 gene, causative mutations in F8 cannot be simultaneously detected in one step by traditional molecular analysis, and genetic molecular diagnosis and prenatal screening of HA still face significant difficulties and challenges in clinical practice. Therefore, we aimed to develop and validate an efficient, accurate, and time-saving method for the genetic detection of HA.

METHODS

A comprehensive analysis of hemophilia A (CAHEA) method based on long-range PCR and long-read sequencing (LRS) was used to detect F8 gene mutations in 14 clinical HA samples. The LRS results were compared with those of the conventional methods to evaluate the accuracy and sensitivity of the proposed approach.

RESULTS

The CAHEA method successfully identified 14 F8 variants in all probands, including 3 small insertion deletions, 4 single nucleotide variants, and 7 intron 22 inversions in a "one-step" manner, of which 2 small deletions have not been reported previously. Moreover, this method provided an opportunity to analyze the mechanism of rearrangement and the pathogenicity of F8 variants. The LRS results were validated and found to be in 100% agreement with those obtained using the conventional method.

CONCLUSION

Our proposed LRS-based F8 gene detection method is an accurate and reproducible genetic screening and diagnostic method with significant clinical value. It provides efficient, comprehensive, and accurate genetic screening and diagnostic services for individuals at high risk of HA as well as for premarital and prenatal populations.

Genotype-phenotype analyses of Iranian patients with hemophilia B (Leyden -) and hemophilia B (Leyden +): A single-center study

BACKGROUND

There is a high prevalence of inherited bleeding disorders in Iran, such as hemophilia A (HA) and hemophilia B (HB). This study aimed to analyze the molecular and clinical profiles of patients with HB.

METHODS

A single-center study was conducted among patients with severe HB between March 20, 2000, and June 31, 2023. The polymerase chain reaction (PCR) amplification was used for all of the major regions, such as the promoter, the exons, the adjacent intronic regions, and the untranslated regions of the F9 gene. Finally, Sanger sequencing was performed on the PCR products.

RESULTS

A total of 111 HB patients (17 with HB [Leyden +] and 94 with HB [Leyden -]) were enrolled in this study. Among 94 patients with HB (Leyden -), 59 (62.8 %) had missense, 21 (22.3 %) had nonsense, and 8 (8.5 %) had frameshift mutations. Moreover, the most frequent pathogenic variant in HB (Leyden +) was c.-17 A>G in this study.

CONCLUSION

The results of this study confirm that HB is caused by a wide range of molecular defects in Iran. Thus, by knowing the genotypes and phenotypes, we would be able to stratify the patients which is important in terms of their management and outcome.

Anesthetic considerations for joint replacement surgery in hemophilic arthropathy: a comprehensive review

Managing hemophilia in patients undergoing joint replacement surgery requires a comprehensive approach encompassing preoperative assessment, meticulous intraoperative care, and tailored postoperative management. Evaluation of joint integrity, bleeding history, and inhibitor presence guides surgical planning and hemostatic therapy selection to optimize outcomes. During surgery, careful attention to factor replacement, antibiotic prophylaxis, anesthetic techniques, and orthopedic strategies minimizes bleeding risk and enhances surgical success. Postoperatively, effective pain management, continued hemostatic therapy, and individualized rehabilitation programs are vital for facilitating recovery and preventing complications. Close monitoring for potential complications, such as periprosthetic joint infection and recurrent hemarthrosis, allows for prompt intervention when necessary. Overall, a collaborative approach involving hematologists, orthopedic surgeons, anesthesiologists, and rehabilitation specialists ensures comprehensive care tailored to the unique needs of patients with hemophilia undergoing joint replacement surgery, ultimately optimizing outcomes and improving quality of life. This holistic approach addresses the multifaceted challenges posed by hemophilia and joint replacement surgery, providing patients with the best possible chance for successful outcomes and long-term joint function. By integrating specialized expertise from multiple disciplines and implementing evidence-based strategies, healthcare providers can effectively manage hemophilia in the context of joint replacement surgery, mitigating risks and maximizing benefits for patients.

Outcome measures in hemophilia: current and future perspectives

INTRODUCTION

Hemophilia can detrimentally affect patients' quality of life and likelihood of survival. In the evolving landscape of therapies, the therapeutic gain of each treatment must be understood to accurately position it in the therapeutic armamentarium. Accordingly, appropriate outcomes must be measured with appropriate tools.

AREAS COVERED

Our narrative review (PubMed search for 'hemophilia AND outcome' until June 2023), provides a compendium of outcome measures used in hemophilia clinical research. To define each outcome measure's relative value and applicability, several characteristics are critically discussed.

EXPERT OPINION

Bleeding assessment, first annual/annualized bleeding rate, remains central in evaluating the efficacy and safety of hemophilia treatments. As modern therapies improve clinical outcomes toward zero bleeding events, this endpoint may become less sensitive to detect differences between therapeutic approaches. Technological advancements necessitate the adaptation of outcome measures to address infrequent bleeding events, age-related comorbidities, and laboratory parameters with limited comparability after different treatments. Considerable effort has been dedicated to the development of tools that comprehensively assess coagulation, such as thrombin generation assays. Patient-reported outcome measures are gaining importance although limited by their subjectivity. A definitive set of research outcome measures remains elusive. Outcomes may need to be tailored to different therapeutic interventions.

The role of coagulation factors VIII, IX and XI in the prediction and mediation of recurrent thrombotic events in children with non-central venous catheter deep vein thrombosis

BACKGROUND

The role of elevated coagulation factors VIII (FVIII), FIX, FXI for the prediction of recurrent thrombotic events in children after an index non-central venous catheter (non-CVC) related deep vein thrombosis (DVT) remains unclear.

OBJECTIVE

This study investigates the predictive role of FVIII, FIX, and FXI for recurrent thrombosis in children with index non-CVC DVTs, and the mediation effect of FVIII on chronic inflammation and recurrent thrombosis.

METHODS

Children aged 0-18 years diagnosed with an index non-CVC related DVT (1993-2020) were included in this single-center retrospective cohort study. Plasma levels of FVIII, FIX, FXI were measured cross-sectionally ≥30 days after the acute DVT. The association between the continuous variables FVIII, FIX, FXI and thrombosis recurrence was investigated using uni- and multivariable logistic regression, adjusting for age, sex, and chronic inflammation. Mediation analysis assessed the role of FVIII as a mediator between chronic inflammation and recurrent thrombosis. Ethics approval was obtained.

RESULTS

A total of 139 children with an index non-CVC related DVT were included. Thirty-eight (27 %) had a recurrent thrombosis at a median of 237 days (P25-P75 65-657 days) after the index DVT. In uni- and multivariable-analysis, FVIII, FIX or FXI did not predict thrombosis recurrence; However, chronic inflammation was an independent predictor. There was no evidence that FVIII mediated the effect of chronic inflammation on thrombosis recurrence.

CONCLUSION

We found no evidence that elevated FVIII, FIX or FXI predicted thrombosis recurrence, or evidence of a mediating role of FVIII. Underlying chronic inflammation predicted venous recurrent thrombotic events in this cohort.

Clot formation and fibrinolysis assays reveal functional differences among hemostatic agents in hemophilia A plasma

Background

Measuring the activity of hemostatic agents used to treat hemophilia A often requires drug-specific assays. In vitro assays show hemophilic clots have abnormal characteristics, including prolonged clotting time and decreased resistance to fibrinolysis. The ability of certain agents to correct these parameters in vitro is associated with hemostatic efficacy in vivo.

Objectives

To compare effects of established and emerging hemostatic agents on clot formation and fibrinolysis in hemophilia A plasma.

Methods

Pooled and individual hemophilia A platelet-poor plasmas were spiked with replacement (recombinant factor VIII [rFVIII], PEGylated rFVIII, polysialylated rFVIII, and porcine rFVIII) or bypassing (emicizumab, rFVIIa, and activated prothrombin complex concentrate) products. Effects on tissue factor-initiated clot formation and fibrinolysis were measured by turbidity.

Results

Compared to normal pooled plasma, hemophilia-pooled plasma showed reduced clot formation and increased fibrinolysis, and all replacement agents improved these characteristics. rFVIII and PEGylated rFVIII produced similar effects at similar concentrations, whereas polysialylated rFVIII produced slightly higher and porcine rFVIII slightly lower effects at these concentrations. Bypassing agents enhanced clot formation and stability, but patterns differed from replacement agents. The clotting rate showed a concentration-response relationship for all agents. High concentrations of all products produced effects that exceeded the normal range in at least some parameters. Responses of individual donors varied, but all agents improved clot formation and stability in all donors tested.

Conclusion

Clotting and fibrinolysis assays reveal hemostatic effects of replacement and bypassing therapies at clinically relevant concentrations. These assays may help characterize hemostatic agents and optimize dosing.

Emicizumab as a Promising Form of Therapy for Type A Hemophilia - A Review of Current Knowledge from Clinical Trials

Hemophilia is a plasma bleeding disorder characterized by a deficiency of certain blood clotting factors. The most common forms of this disease, i.e., type A and type B, affect approximately 400,000 people worldwide. Without appropriate treatment ensuring the proper coagulation cascade, this disease may lead to serious disability. Minimizing patient discomfort is possible via replacement therapy, consisting of the substitution of a missing coagulation factor via intravenous administration. Frequent medication and the risk related to factor inhibitors are significant disadvantages, necessitating the improvement of current therapies or the development of novel ones. This review examines the humanized bispecific antibody Emicizumab which ensures hemostasis by mimicking the action of the coagulation factor VIII, a deficiency of which causes type A hemophilia. The paper outlines the topic and then summarizes available clinical trials on Emicizumab in type A hemophilia. Several interventional clinical trials have found Emicizumab to be effective in decreasing bleeding episodes and raising patient satisfaction among various hemophilia A populations. Current Emicizumab-related trials are forecast to be completed between 2024 and 2030, and in addition to congenital hemophilia A, the trials cover acquired hemophilia A and patients playing sports. Providing a more comprehensive understanding of Emicizumab may revolutionize the management of hemophilia type A and improve quality of life. Conclusively, Emicizumab is a gentler therapy owing to subcutaneous delivery and fewer injections, which reduces injection-site reactions and makes therapy less burdensome, ultimately decreasing hospital visits and indirect costs.

To Clot or Not to Clot: Is That the Question?

Hemostasis can be defined as a homeostatic process in which the body attempts to minimize loss of blood by balancing out pro- and anti-procoagulant forces [...].