Advances in the treatment of inherited coagulation disorders

50 Years of Pediatric Hemostasis: Knowledge, Diagnosis, and Treatment

Studies from the past 50 years have contributed to the expanding knowledge regarding developmental hemostasis. This is a dynamic process that begins in the fetal phase and is characterized by physiological variations in platelet counts and function, and concentrations of most coagulation factors and the native coagulation inhibitors in early life, as compared with adulthood. The developmental hemostasis studies since the 1980 to 1990s established the laboratory reference values for coagulation factors. It was only a decade or two later, that thromboelastography (TEG) or (rotational thromboelastometry [ROTEM]) as well as thrombin generation studies, provided special pediatric reference values along with the ability to evaluate clot formation and lysis. In addition, global whole blood-based clotting assays provided point of care guidance for proper transfusion support to children hospitalized in intensive care units or undergoing surgery. Although uncommon, thrombosis in children and neonates is gaining increasing recognition, typically as a secondary complication in sick children. Bleeding in children, and particularly intracerebral hemorrhage in newborns, still represent a therapeutic challenge. Notably, our review will outline the advancements in understanding developmental hemostasis and its manifestations, with respect to the pathophysiology of thrombosis and bleeding complications in young children. The changes of transfusion policy and approach to thrombophilia testing during the last decade will be mentioned. Subsequently, a brief summary of the data on anticoagulant treatments in pediatric patients will be presented. Finally, we will point out the 10 most cited articles in the field of pediatric and neonatal hemostasis.

A multianalytical approach to investigate the effect of nanofiltration on plasma-derived factor IX clinical lots

Plasma-derived proteins are a subset of relevant biotherapeutics also known as "well-characterized biologicals". They are enriched from plasma through several steps of physical and biochemical methodologies, reaching the regulatory accepted standards of safety, levels of impurities, activity and lot-to-lot consistency. Final products accepted for commercialization are submitted to tight analytical, functional and safety controls by a number of different approaches that fulfill the requirements of sensitivity and reliability. We report here the use of a multianalytical approach for the comparative evaluation of different lots of Factor IX isolated from plasma preparations and submitted or not to a step of nanofiltration. The approach include, among the other, proteomic techniques based on both MALDI-TOF and LC-MS Orbitrap mass spectrometry, circular dichroism for structural characterization, chromatographic and electrophoretic techniques, ELISA and functional assays based on clotting activity and binding to known anticoagulants. Comparative data obtained on two sets of nanofiltered and non-nanofiltered lots with different final activity show that the products have substantially overlapping profiles in terms of activity, contaminants, structural properties and protein content, suggesting that the proposed multianalytical approach is robust enough to be used for the routine validation of clinical lots.

Treatment of musculo-skeletal pain in haemophilia

Musculo-skeletal pain treatment is inadequate in many haemophilic patients. Analgesics are used only by 36% of adult patients. FVIII/FIX intravenous infusion is mainly used to lessen pain, followed in frequency by usage of NSAIDS (primarily COX-2 inhibitors). In about 30% of patients, pain continues after infusion of F VIII/IX. In acute haemarthroses pain treatment must continue until total disappearance (checked by ultrasonography) and include haematologic treatment, short-term rest of the involved joint, cryotherapy, joint aspiration and analgesic medication (paracetamol in mild pain, metamizole for more intense pain, and in a few precise patients, soft opioids such as codeine or tramadol). In the circumstance of intolerable pain we should use morphine hydrochloride either by continual infusion or a patient-controlled analgesia (PCA) pump, determined by the age, mental condition and grade of observance of the patient. Epidural blocks utilizing bupivacaine and fentanyl may be very efficacious as well. Three main strategies to alleviate chronic musculo-skeletal pain secondary to haemophilic arthropathy (joint degeneration) exist: pharmacologic management, physical medicine and rehabilitation, and intra-articular injections. As for pharmacologic management, NSAIDs (ibuprofen, diclofenac, celecoxib, robecoxib) are better than paracetamol. The advantages of tramadol or tramadol/paracetamol and non-tramadol opioids are scanty. With respect to physical medicine and rehabilitation, there is insufficient confirmation that a brace has supplementary favourable effect compared with isolated pharmacologic management. Land-based curative exercise and watery exercise have at the minimum a tiny short-run benefit. Curative ultrasound can be helpful (poor quality of evidence). The efficacy of transcutaneous electrostimulation (TENS) for pain mitigation has not been proved. Electrical stimulation treatment can procure notable ameliorations. With respect to intra-articular injections, viscosupplementation appears to be a useful method for pain alleviation in the short-run (months). The short-run (weeks) advantage of intra-articular corticosteroids in the treatment of joint pain has been shown.

A cross-sectional study of complementary and alternative medicine use in patients with coagulation disorders in Southern Iran

OBJECTIVE

Complementary and alternative medicine (CAM) use has an increasing trend around the world. Despite the wild application of CAM in patients with coagulation disorders, its efficacy is still questioned by many studies. The aim of this study was to determine the frequency and types of CAM usage, and the factors affecting CAM use among patients with bleeding disorders.

METHODS

This cross-sectional study investigated the usage of CAM with a standard validated questionnaire in coagulopathic patients who were referred to Dastgheib Hospital, an educational therapeutic center affiliated to the Shiraz University of Medical Sciences in Shiraz, Southern Iran.

RESULTS

Between December 2015 and May 2016, 75 patients were included in this survey. Severe hemophilia A and rare bleeding disorders were the most frequent among our participants. Overall, nearly half of the studied population (49.3%) used at least one CAM product or practices. The most common products were multivitamin (29.3%), followed by folic acid (21.3%) and chamomile (12%). 32% of the patients resorted to faith healing. The main reasons of using CAM were reported to be increased general health, correction of anemia and thrombocytopenia and control of bleeding tendency.

CONCLUSION

CAM is being used frequently in patients with coagulation disorders like many other chronic illnesses all around the world. Due to emerging concern regarding the safety and possible interaction with the conventional medicine, it is necessary to develop basic data about the hematologic effects of these methods in order to use them more safely.

Predictors of quality of life among adolescents and young adults with a bleeding disorder

BACKGROUND

Health-related quality of life (HRQoL) in adolescents and young adults with bleeding disorders is under-researched. We aimed to describe factors related to HRQoL in adolescents and young adults with hemophilia A or B or von Willebrand disease.

METHODS

A convenience sample of volunteers aged 13 to 25 years with hemophilia or von Willebrand disease completed a cross-sectional survey that assessed Physical (PCS) and Mental (MCS) Component Summary scores on the SF-36 questionnaire. Quantile regression models were used to assess factors associated with HRQoL.

RESULTS

Of 108 respondents, 79, 7, and 14% had hemophilia A, hemophilia B, and von Willebrand disease, respectively. Most had severe disease (71%), had never developed an inhibitor (65%), and were treated prophylactically (68%). Half of patients were aged 13 to 17 years and most were white (80%) and non-Hispanic (89%). Chronic pain was reported as moderate to severe by 31% of respondents. Median PCS and MCS were 81.3 and 75.5, respectively. Quantile regression showed that the median PCS for women (61% with von Willebrand disease) was 13.1 (95% CI: 2.4, 23.8; p = 0.02) points lower than men. Ever developing an inhibitor (vs never) was associated with a 13.1-point (95% CI: 4.7, 21.5; p < 0.01) PCS reduction. MCS was 10.0 points (95% CI: 0.7, 19.3; p = 0.04) higher for prophylactic infusers versus those using on-demand treatment. Compared with patients with no to mild chronic pain, those with moderate to severe chronic pain had 25.5-point (95% CI: 17.2, 33.8; p < 0.001) and 10.0-point (95% CI: 0.8, 19.2; p = 0.03) reductions in median PCS and MCS, respectively.

CONCLUSIONS

Efforts should be made to prevent and manage chronic pain, which was strongly related to physical and mental HRQoL, in adolescents and young adults with hemophilia and von Willebrand disease. Previous research suggests that better clotting factor adherence may be associated with less chronic pain.

Intracranial Hemorrhage as the First Manifestation of Severe Congenital Factor X Deficiency in a 20-Month-Old Male: Case Report and Review of the Literature

Factor X deficiency (FXD) is a rare bleeding disorder, which can result in severe bleeding symptoms such as intracranial hemorrhage (ICH). The most common bleeding symptoms are epistaxis and gum bleeding. ICH is reported in 9-26% of all patients with FXD, mostly during the first month of life. Here, we present a rare case of a male presenting with ICH at the age of 20 months as the first manifestation of FXD. Secondary prophylaxis with factor X substitution once weekly prevented further bleeding.

Engineering trypsin for inhibitor resistance

The development of effective protease therapeutics requires that the proteases be more resistant to naturally occurring inhibitors while maintaining catalytic activity. A key step in developing inhibitor resistance is the identification of key residues in protease-inhibitor interaction. Given that majority of the protease therapeutics currently in use are trypsin-fold, trypsin itself serves as an ideal model for studying protease-inhibitor interaction. To test the importance of several trypsin-inhibitor interactions on the prime-side binding interface, we created four trypsin single variants Y39A, Y39F, K60A, and K60V and report biochemical sensitivity against bovine pancreatic trypsin inhibitor (BPTI) and M84R ecotin. All variants retained catalytic activity against small, commercially available peptide substrates [kcat /KM  = (1.2 ± 0.3) × 10(7) M(-1 ) s(-1) . Compared with wild-type, the K60A and K60V variants showed increased sensitivity to BPTI but less sensitivity to ecotin. The Y39A variant was less sensitive to BPTI and ecotin while the Y39F variant was more sensitive to both. The relative binding free energies between BPTI complexes with WT, Y39F, and Y39A were calculated based on 3.5 µs combined explicit solvent molecular dynamics simulations. The BPTI:Y39F complex resulted in the lowest binding energy, while BPTI:Y39A resulted in the highest. Simulations of Y39F revealed increased conformational rearrangement of F39, which allowed formation of a new hydrogen bond between BPTI R17 and H40 of the variant. All together, these data suggest that positions 39 and 60 are key for inhibitor binding to trypsin, and likely more trypsin-fold proteases.

A missense variant in CST3 exerts a recessive effect on susceptibility to age-related macular degeneration resembling its association with Alzheimer's disease

Age-related macular degeneration (AMD) and Alzheimer's disease (AD) are degenerative, multifactorial diseases involving age-related accumulation of extracellular deposits linked to dysregulation of protein homeostasis. Here, we strengthen the evidence that an nsSNP (p.Ala25Thr) in the cysteine proteinase inhibitor cystatin C gene CST3, previously confirmed by meta-analysis to be associated with AD, is associated with exudative AMD. To our knowledge, this is the first report highlighting a genetic variant that increases the risk of developing both AD and AMD. Furthermore, we demonstrate that the risk associated with the mutant allele follows a recessive model for both diseases. We perform an AMD-CST3 case-control study genotyping 350 exudative AMD Caucasian individuals. Bringing together our data with the previously reported AMD-CST3 association study, the evidence of a recessive effect on AMD risk is strengthened (OR = 1.89, P = 0.005). This effect closely resembles the AD-CST3 recessive effect (OR = 1.73, P = 0.005) previously established by meta-analysis. This resemblance is substantiated by the high correlation between CST3 genotype and effect size across the two diseases (R(2) = 0.978). A recessive effect is in line with the known function of cystatin C, a potent enzyme inhibitor. Its potency means that, in heterozygous individuals, a single functional allele is sufficient to maintain its inhibitory function; only homozygous individuals will lack this form of proteolytic regulation. Our findings support the hypothesis that recessively acting variants account for some of the missing heritability of multifactorial diseases. Replacement therapy represents a translational opportunity for individuals homozygous for the mutant allele.

Industrial production of clotting factors: Challenges of expression, and choice of host cells

The development of recombinant forms of blood coagulation factors as safer alternatives to plasma derived factors marked a major advance in the treatment of common coagulation disorders. These are complex proteins, mostly enzymes or co-enzymes, involving multiple post-translational modifications, and therefore are difficult to express. This article reviews the nature of the expression challenges for the industrial production of these factors, vis-à-vis the translational and post-translational bottlenecks, as well as the choice of host cell lines for high-fidelity production. For achieving high productivities of vitamin K dependent proteins, which include factors II (prothrombin), VII, IX and X, and protein C, host cell limitation of γ-glutamyl carboxylation is a major bottleneck. Despite progress in addressing this, involvement of yet unidentified protein(s) impedes a complete cell engineering solution. Human factor VIII expresses at very low levels due to limitations at several steps in the protein secretion pathway. Protein and cell engineering, vector improvement and alternate host cells promise improvement in the productivity. Production of Von Willebrand factor is constrained by its large size, complex structure, and the need for extensive glycosylation and disulfide-bonded oligomerization. All the licensed therapeutic factors are produced in CHO, BHK or HEK293 cells. While HEK293 is a recent adoption, BHK cells appear to be disfavored.

Novel products for haemostasis

The primary major issue in haemophilia treatment remains the development of inhibitors. Recently two novel bypassing products have been developed. First, a humanized bispecific antibody against FIXa and FX, termed hBS23, was produced utilizing these two molecules placed into a spatially appropriate position to mimic FVIIIa, and recently this mimetic activity and the pharmacokinetics of the original antibody were improved by engineering the charge properties of the variable region within the immunoglobulin. Using the new antibody, termed ACE910, a phase 1 study in 64 Japanese and Caucasian healthy adults was performed and data from this trial suggested that the product had medically acceptable safety and tolerability profiles. The other new bypassing agent is named MC710, and consists of a mixture of plasma-derived FVIIa and FX. Preclinical studies using in vitro and in vivo haemophilia B inhibitor monkey models indicated that the haemostatic effects of FVIIa and FX were enhanced by simultaneous administration. Results from phase I and II clinical studies suggested that MC710 had equal or greater pharmacokinetic (PK), pharmacodynamic (PD), efficacy and safety profiles than conventional bypassing agents in the treatment of joint bleeding in haemophilia patients with inhibitors. Another significant current issue in this context is the increased medical cost of conventional treatment due to the higher consumption of concentrates. Biosimilar products may offer advantages in these circumstances and may offer a less expensive alternative. Regulatory issues, however, together with acceptability of biosimilar materials and reimbursement policies as well as supply and demand incentives remain to be considered. Rare bleeding disorders (RBDs) have attracted less attention from the pharmaceutical industry than haemophilia or von Willebrand disease due to the limited number of patients involved. Many cases of this type have been treated, therefore, using fresh frozen plasma (FFP) or prothrombin complex concentrates (PCCs) which carry serious risks of infections, allergic reactions and fluid overload. Several specific plasma-derived or recombinant products including fibrinogen, FVIIa, FXI and FXIII have now become available, however, and a phase III clinical study of recombinant FXIIIa has recently been completed demonstrating safety and efficacy of substances of this nature.

Coping in adult patients with severe haemophilia

An adequate use of coping strategies could help patients to deal with disease-related stress. The study aim was to explore coping behaviour in adult patients with severe haemophilia and its possible determinants. Coping was assessed through three basic dimensions (task-oriented, emotion-oriented and avoidance coping), using the short version of the Coping Inventory for Stressful Situations (CISS-21). Patients' scores were compared with Dutch working men (N = 374), according to three categories: low use (<P25 of normal), average use (P25-P75) and high use (>P75). Determinants were measured using questionnaires on activities (Haemophilia Activities List), participation (Impact on Participation and Autonomy Questionnaire), physical functioning [physical component of the Dutch Arthritis Impact Measurement Scales-2 (D-AIMS2)] and socio-psychological health (psychological component of the D-AIMS2). In total, 86 adults with severe haemophilia (FVIII/IX<1%) were included. The median age was 38 years (range: 18-68) with 85% affected with haemophilia A and 75% using prophylaxis. Patients with haemophilia used task-oriented coping as frequently as the control group (P = 0.13); but used significantly less emotion-oriented coping (57% vs. 25%, P < 0.05) and avoidance coping (P < 0.05). Emotion-oriented coping showed a strong correlation with socio-psychological health (r = 0.67) and weak correlations with participation (r = 0.32) and social interaction (r = 0.29). Other associations of coping strategies with patient characteristics of health status could not be demonstrated. Overall, patients predominantly used the task-oriented approach to deal with their disease; the use of this strategy was comparable to the control group. Having a poor psychological health, less social interaction and/or less participation in daily life was associated with an increased use of emotion-oriented coping.