Endothelial specific isoform of type XVIII collagen (COL-18N): A marker of vascular integrity in haemophilic arthropathy.

BACKGROUND: Haemophilic arthropathy (HA) is a major complication in haemophilia. Collagens IV, XV and XVIII are responsible for maintaining the integrity of the vessel wall in the joint. Following joint remodelling and damage, the short isoform of collagen type XVIII (COL-18N) is degraded, releasing measurable fragments. Our goal was to quantify the specific isoform COL-18N in haemophilia A patients and to assess its relation to the clinical and radiological data as well as haemophilia joint health score (HJHS), functional independence score for haemophilia (FISH), and haemophilia quality of life (Haemo-Qol). METHODS: This cross-sectional study included 50 haemophilia A patients recruited from the Paediatric Haematology and Oncology unit, Ain Shams University, Cairo, Egypt. Quantification of COL-18N was done by ELISA. Assessment of joint state clinically using FISH and HJH scores and radiologically by X-rays and ultrasound. RESULTS: Haemophilia A patients had significantly higher median COL-18N levels compared to the control group. Inhibitor positive and negative haemophilia A patients as well as those on non-steroidal anti-inflammatory drug and those not had comparable COL-18N levels. Patients with ≥2 target joints had significantly higher COL-18N level compared to those with one or those without target joints. There were significant positive correlations between COL-18N level and the total HJHS, Haemo-Qol, the HEAD-US score and annual bleeding rate. CONCLUSION: Our results demonstrated a high level of COL-18N in haemophilia A patients and argued its benefit as a potential marker for monitoring the development of haemophilic arthropathy and tailoring the optimal treatment to prevent further joint damage.

The potential role of emicizumab prophylaxis in severe von Willebrand disease.

BACKGROUND: Severe von Willebrand disease (VWD) may be associated with chronic joint damage and may require prophylactic therapy. Emicizumab is a humanized bispecific antibody, which mimics the function of coagulation factor VIII (FVIII), and it has been approved for prophylaxis in hemophilia A. METHODS: This is the first study assessing the potential future role of emicizumab as an alternative prophylactic treatment in patients with severe VWD, based upon a thrombin generation (TG) ex vivo analysis. We report 51 weeks of successful off label emicizumab prophylaxis in a child with severe VWD and recurrent hemarthroses and progressive arthropathy despite adherence to previous prophylaxis with replacement therapy. RESULTS AND CONCLUSIONS: Our work demonstrated that ex vivo spiking with emicizumab increased TG in plasma from patients with type 3 VWD. Similar TG results were observed in our treated patient, whose therapy was well tolerated without any adverse events. Both in vitro and ex vivo TG data support sufficient hemostasis without exceeding the range seen in healthy volunteers. Further collaborative studies on the efficacy and safety of emicizumab prophylaxis in severe VWD is warranted.

Biochemical marker research in hemophilic arthropathy: A systematic review.

Hemophilic arthropathy (HA) causes major morbidity. Breakthrough therapies reduce the bleeding frequency tremendously, but well-defined joint outcome assessments with a focus on early changes and subclinical damage are lacking. Biomarkers reflecting joint tissue turnover/inflammation might be useful to predict invalidating arthropathy. This systematic review summarized and categorized publications on blood/urinary biomarkers in HA to provide leads for implementation. A PubMed/EMBASE search was performed on September 9, 2019. All publications were assessed and allocated to one or several BIPED-categories, based on the utility of biomarkers. Of the initial 1307 publications found, 27 were eligible for inclusion. The majority (81%, n = 32/42) was cross-sectional in design, including relatively small numbers of patients (median 44, interquartile range 35-78). Fourteen percent (n = 6/42) investigated dynamic changes around a bleeding or treatment. Only two studies investigated the prognostic value of biomarkers. Most promising biomarkers were serum Coll2-1, COL-18N, COMP, C1,2C, C2M, CS846, MIF, plasma sVCAM-1 and urinary CTX-II. Comparing performances and pooling data was not possible due to heterogeneity. Currently, biomarker research in HA is still in an explorative stage and not yet sufficient for translation into daily practice. Clearly, larger homogeneous longitudinal studies in well-defined populations should be performed for further development.

Decreased Bleeding Rates in Patients with Hemophilia A Switching from Standard-Half-Life FVIII to BAY 94-9027 Prophylaxis.

BAY 94-9027 (damoctocog alfa pegol, Jivi) is an extended-half-life recombinant factor VIII (rFVIII) shown to be well-tolerated and efficacious in bleeding prevention in previously treated patients with severe hemophilia A. During the PROTECT VIII study, prophylaxis patients received BAY 94-9027 at intervals determined based on their bleeding phenotype, observed during a 10-week run-in treatment period with twice-weekly dosing. Those with ≤ 1 spontaneous joint or muscle bleed were randomized to either 45 to 60 IU/kg every 5 days or 60 IU/kg every 7 days; patients could increase dosing frequency to every 5 days or twice weekly in the case of bleeds. Those enrolled after the randomization arms were full, and those with ≥ 2 bleeds in the run-in period, received 30 to 40 IU/kg twice weekly. Patients completing the main study could receive open-label BAY 94-9027 in the extension phase. Dosing regimen, total, and joint annualized bleeding rates were analyzed over three periods: prestudy, main study, and extension. A total of 80 patients who were on prophylaxis treatment prior to and during the study and had prior bleed data available were evaluated in this post hoc analysis of PROTECT VIII. Most patients (> 80%) required fewer infusions with BAY 94-9027 prophylaxis versus their previous standard-half-life (SHL) rFVIII product. Lower bleeding and joint bleeding rates were observed over time from the prestudy to the extension study period in all treatment regimens. Compared with SHL FVIII, BAY 94-9027 prophylaxis allows patients to reduce infusion frequency with maintained or improved protection from bleeds.

The Progression of Hemophilic Arthropathy: The Role of Biomarkers.

BACKGROUND: Hemophilia A and B are X-linked congenital bleeding disorders characterized by recurrent hemarthroses leading to specific changes in the synovium and cartilage, which finally result in the destruction of the joint: this process is called hemophilic arthropathy (HA). This review highlights the most prominent molecular biomarkers found in the literature to discuss their potential use in the clinical practice to monitor bleeding, to assess the progression of the HA and the effectiveness of treatments. METHODS: A review of the literature was performed on PubMed and Embase, from 3 to 7 August 2020. Study selection and data extraction were achieved independently by two authors and the following inclusion criteria were determined a priori: English language, available full text and articles published in peer-reviewed journal. In addition, further articles were identified by checking the bibliography of relevant articles and searching for the studies cited in all the articles examined. RESULTS: Eligible studies obtained at the end of the search and screen process were seventy-three (73). CONCLUSIONS: Despite the surge of interest in the clinical use of biomarkers, current literature underlines the lack of their standardization and their potential use in the clinical practice preserving the role of physical examination and imaging in early diagnosis.

Modeling to Predict Factor VIII Levels Associated with Zero Bleeds in Patients with Severe Hemophilia A Initiated on Tertiary Prophylaxis.

BACKGROUND: Factor VIII (FVIII) trough levels > 1 IU/dL in patients with severe hemophilia A receiving regular prophylaxis may optimize bleed protection. OBJECTIVES: In this post hoc analysis of patients receiving tertiary prophylaxis for approximately 1 year, the relationship between estimated FVIII levels and reported bleeds was investigated to predict the potential for zero bleeds. METHODS: Sixty-three patients (median [range] age, 28 [7-59] years) with severe hemophilia A (229 bleeds) were included. FVIII levels at time of each bleed were estimated from single-dose individual pharmacokinetics. The highest estimated FVIII level at which patients experienced a bleed was considered the "potentially effective trough level" for that bleed type. Kaplan-Meier estimates of proportions of patients with no bleeds above certain estimated FVIII levels were determined. Those not experiencing a bleed in the trial were assumed to have a bleed at 0 IU/dL (pragmatic approach) or at their median trough level (conservative approach). RESULTS: Kaplan-Meier estimates based on pragmatic approach predicted zero all bleeds, joint bleeds, and spontaneous joint bleeds in 1 year in 40, 43, and 63% of patients, respectively, when the potentially effective trough FVIII level was set at 1 IU/dL. Between 1 and 10 IU/dL, every 1 IU/dL rise in estimated FVIII level was associated with an additional 2% of patients having zero all bleeds. CONCLUSION: This post hoc analysis confirms benefits with trough levels of approximately 1 to 3 IU/dL in most patients starting tertiary prophylaxis; prophylaxis with higher trough levels may help patients to achieve zero bleeds.

Serological biomarkers in hemophilic arthropathy: Can they be used to monitor bleeding and ongoing progression of blood-induced joint disease in patients with hemophilia?

In patients with hemophilia, levels of uCTX-II and sCS846 increase 5 days after joint hemorrhage with respect to the initial value. In other words, in patients with established hemophilic arthropathy, the aforesaid biomarkers of joint tissue damage augment shortly after the first joint hemorrhage. In patients with hemophilia treated on demand, a correlation has been found between magnetic resonance imaging scores and the CS846 biomarker. Patients with hemophilia having more than one joint with advanced arthropathy have shown high levels of circulating soluble vascular cell adhesion molecule-1 (sVCAM-1). In addition, sVCAM-1 levels in these patients are associated with the severity of hemophilic arthropathy. In patients with hemophilia, cartilage degradation is increased by 25% compared with controls, as measured by some biomarkers (C2M, CTX-II and COMP). Levels of the cartilage degradation enzyme, ADAMTS5, are 10% lower in patients with hemophilia. Bone formation (PINP) is 25% lower in patients with hemophilia, whereas bone resorption (CTXI) is 30% greater. Acute inflammation (hsCRP) is 50% greater, whereas chronic inflammation (CRPM) is 25% lower. The hsCRP/CRPM ratio is 60% higher in patients with hemophilia than in controls. A panel of biomarkers that combines C2M, CRPM and ADAMTS5 can distinguish patients with hemophilia from controls with 85.3% accuracy. No strong correlation between biomarkers and the radiological and physical examination of the joint has been found.

Factor VIII replacement is still the standard of care in haemophilia A.

Prophylactic factor VIII (FVIII) has dramatically improved haemophilia A treatment, preventing joint bleeding and halting the deterioration of joint status. FVIII products with an extended plasma half-life further improve patients' quality of life and increase therapeutic adherence. New licensed classes of non-replacement products include prophylactic emicizumab, which is administered subcutaneously up to every 4 weeks. However, this drug is not suitable for acute bleeding episodes or management of major surgery, and long-term data on the impact of emicizumab on joint health, FVIII inhibitor development and thrombotic risk are awaited. Prophylaxis with FVIII replacement remains the standard of care in haemophilia A, with the aim of achieving a level of haemostasis control that allows patients to meet their lifestyle goals.

Impact of Adopting Population Pharmacokinetics for Tailoring Prophylaxis in Haemophilia A Patients: A Historically Controlled Observational Study.

BACKGROUND: Performing individual pharmacokinetics (PK) studies in clinical practice can be simplified by adopting population PK-based profiling on limited post-infusion samples. The objective of this study was to assess the impact of population PK in tailoring prophylaxis in patients with haemophilia A. PATIENTS AND METHODS: Individual weekly treatment plans were developed considering predicted plasma factor activity levels and patients' lifestyle. Patients were trained using a visual traffic-light scheme to help modulate their level of physical activity with respect to factor infusions timing. Annualized joint bleeding rate (ABJR), haemophilia-specific quality of life questionnaire for adults (Haemo-QoL-A) and factor utilization were measured for 12 months before and after tailoring, compared within patients and analysed separately for those previously on prophylaxis (P), situational prophylaxis (SP) or on-demand (OD). RESULTS: Sixteen patients previously on P, 10 on SP and 10 on OD were enrolled in the study. The median (lower, upper quartile) ABJR changed from 2.0 (0, 4.0) to 0 (0, 1.6) for P (p = 0.003), from 2.0 (2.0, 13.6) to 3.0 (1.4, 7.2) for SP (p = 0.183) and from 16.0 (13.0, 25.0) to 2.3 (0, 5.0) for OD (p = 0.003). The Haemo-QoL-A total score improved for 58% of P, 50% of SP and 29% of OD patients. Factor utilization (IU/kg/patient/year) increased by 2,400 (121; 2,586) for P, 1,052 (308; 1,578) for SP and 2,086 (1,498; 2,576) for OD. One of 138 measurements demonstrated a factor activity level below the critical threshold of 0.03 IU/mL while the predicted level was above the threshold. CONCLUSION: Implementing tailored prophylaxis using a Bayesian forecasting approach in a routine clinical practice setting may improve haemophilia clinical outcomes.

Serum Sclerostin Level and Bone Mineral Density in Pediatric Hemophilic Arthropathy.

OBJECTIVE: To assess serum sclerostin levels in relation to severity of arthropathy and bone mineral density (BMD) in children with hemophilic arthropathy. METHODS: This cross-sectional study included 40 male children suffering from Hemophilia A, and 10 matched healthy controls. Assessment of factor VIII deficiency degree, frequency of bleeding, type of treatment, body mass index (BMI), disease severity using the Hemophilia Joint Health Score (HJHS) and lumbar spine (LS) Z score for bone mineral density (BMD) using dual-energy X-ray absorbiometry was done. Serum sclerostin levels were measured for all patients and controls. RESULTS: Significant difference of serum sclerostin levels between the patient and control groups with Mean ± SD (0.09 ± 0.07 ng/ml) and (0.04 ± 0.01 ng/ml) (P value = 0.028) respectively was found. Significant positive correlations between serum sclerostin levels and the patients' age, and HJHS (P value <0.05) were found, while it had negative correlation with DEXA Z score, not reaching a significant value. LS-BMD-Z score levels ranged from (-4.5 to 1.2), with 15 patients with low BMD Z score (less than -2) representing 37.5% of total patients. CONCLUSIONS: Serum sclerostin levels are elevated in hemophilic children denoting bone metabolism affection and correlates with increased age, and HJHS. Increased levels of serum sclerostin may identify hemophilic patients at high risk for developing osteoporosis.

Inherited Bleeding Disorders-Experience of a Not-for-Profit Organization in Pakistan.

Patient registry is a powerful tool for planning health care and setting groundwork for research. This survey reports a detailed registry of inherited bleeding disorders (IBD) and their management at a not-for-profit organization in a developing country to form the basis for planning development and research. We reviewed medical records of patients with IBD from 8 hemophilia treatment centers of Fatimid Foundation located in various cities. Information collected included sociodemographic data, diagnostic tests, severity of hemophilia A and B, number of bleeding episodes per year, site and frequency of hemarthrosis, and seropositivity for viral diseases. We analyzed 1497 patients from November 1, 2015, to April 30, 2016. There were 1296 (87%) males and 201 (13%) females with a mean age of 24.5 (11) years (range, 6 months to 65 years). Hemophilia A constituted the bulk of IBD (848, 57%) followed by von Willebrand disease (172, 11%), hemophilia B (144, 10%), platelet function defect (106, 7%), and rare bleeding disorders (70, 5%). Mucocutaneous bleeding (1144, 76%) and hemarthrosis (1035 patients, 69%) were the main complications. There were 1026 (69%) patients who received only blood components for treatment of any bleeding episode while the remaining 464 (31%) were on combination therapy (blood components and factor concentrate). Seroreactivity for hepatitis C was frequent (28%), while hepatitis B (1%) and human immunodeficiency virus (0.01%) were less commonly seen. This study was an important step toward a patient registry in a hemophilia treatment center in Pakistan. Hemophilia A is the most common bleeding disorder and hepatitis C is the most frequent treatment-related complication.

Acute Haemarthrosis in the Haemophilia A Rat Generates a Local and Systemic Proinflammatory Response.

Background Replacement therapy with coagulation factor VIII (FVIII) concurrent with bleeds (on-demand) in haemophilia A (HA) patients has been hypothesized to increase the risk for antidrug antibodies (inhibitors). A danger signal environment, characterized by tissue damage and inflammation at the site of a bleed, is thought to contribute to the anti-FVIII response. The nature of this inflammatory reaction is, however, not fully known, and new insights will be valuable for both managing inhibitors and understanding arthropathy development. Objective To characterize the inflammatory response, locally and systemically, during the first 24 hours following a joint bleed in the HA rat. Methods HA rats received a needle-induced knee joint bleed (n = 83) or a sham procedure (n = 41). Blood samples were collected at selected time points from 0 to 24 hours post injury/sham. Synovial fluid, intra-articular knee tissue and popliteal lymph nodes were collected at 24 hours. Cytokine/chemokine concentrations and gene expression were measured. Results Gene expression analysis revealed a rapid inflammatory response in the injured knees, accompanied by significantly increased levels of specific gene products in the synovial fluid; IL-1ß, TNFα, KC/GRO, IL-6, Eotaxin, MCP-1, MCP-3, MIP-1α, MIP-2, RANTES, A2M and AGP. Plasma analysis demonstrated significantly increased systemic levels of KC/GRO and IL-6 in injured rats already after 5 to 6 hours. Conclusion A rapid proinflammatory response, locally and systemically, characteristic of innate immunity, was demonstrated. Results reveal a more comprehensive inflammatory picture than previously shown, with resemblance to human haemophilic arthropathy, and with unique correlation between gene expression level, synovial concentration and plasma concentration in individual rats.

Safety and efficacy of a glycoPEGylated rFVIII (turoctocog alpha pegol, N8-GP) in paediatric patients with severe haemophilia A.

Turoctocog alfa pegol (N8-GP, Novo Nordisk, Bagsværd, Denmark), an extended half-life glycoPEGylated recombinant factor VIII (rFVIII), is being developed for prophylaxis and treatment of bleeds in haemophilia A patients. pathfinder™5 is a multinational, open-label, single-arm trial to assess safety, efficacy and pharmacokinetics of N8-GP in paediatric (<12 years), previously treated patients. Boys with severe haemophilia A (<1 % FVIII), no history of inhibitors and previously treated with FVIII products (>50 exposure days [ED] for patients aged 0-5 years [younger cohort]; >150 ED for patients aged 6-11 years [older cohort]) were included. For prophylaxis, N8-GP was dosed at 50-75 IU/kg twice weekly; bleeds were treated with 20-75 IU/kg. Half-life was estimated for the patients' previous FVIII product and for N8-GP. Sixty-eight patients received N8-GP; none developed inhibitors and no other concerns were identified. Median annualised bleeding rate was 1.95 (1.94 and 1.97 in the younger and older cohorts, respectively). Twenty-nine patients (42.6 %; 15 younger and 14 older children, respectively) did not report any bleeding while on N8-GP prophylaxis; 39 patients (57.4 %; 19 younger and 20 older children, respectively) reported 70 bleeds (all mild/moderate). N8-GP treatment was successful for 78.6 % of bleeds in all patients, 80.0 % in younger and 77.5 % in older patients. Most bleeds (80.0 %) were treated with ≤2 injections. Half-life ratio between N8-GP and the patients' previous FVIII product was 1.85. N8-GP was well tolerated and provided effective prophylaxis and treatment of bleeds in paediatric patients with severe haemophilia A.

A fusion protein of interleukin-4 and interleukin-10 protects against blood-induced cartilage damage in vitro and in vivo.

Essentials Targeted treatment for hemophilic arthropathy, still causing significant morbidity, is lacking. This study evaluates the efficacy of a fusion of protein of interleukin(IL)-4 and IL-10. In vitro the fusion protein prevents blood-induced cartilage damage in a dose-dependent manner. In hemophilic mice, the IL4-10 fusion protein ameliorates cartilage damage upon joint bleeding. SUMMARY: Background Joint damage still causes significant morbidity in hemophilia. It results from synovial inflammation and direct cartilage-degenerating properties of blood components. Interleukin (IL)-4 and IL-10 have been shown to protect cartilage from blood-induced damage. Recently an IL4-10 fusion protein has been developed to combine the function of IL-4 and IL-10 and increase their bioavailability. Objectives In this study we evaluate whether this IL4-10 fusion protein protects against blood-induced joint damage. Methods In vitro, human cartilage explants were exposed to whole blood and simultaneously to a broad concentration range of the IL4-10 fusion protein. Effects on cartilage matrix turnover were compared with the individual cytokines. Moreover, the influence of the fusion protein and its individual components on IL-1ß and IL-6 production was investigated. In hemophilia A mice, the effect of intra-articular treatment on synovitis and cartilage damage resulting from joint bleeding was evaluated by histochemistry. Results In vitro, the fusion protein prevented blood-induced cartilage damage in a dose-dependent manner, with equal effectiveness to the combination of the separate cytokines. In whole blood cultures 10 ng mL-1 fusion protein completely blocked the production of IL-1ß and IL-6 by monocytes/macrophages. In hemophilic mice, intra-articular injection of IL-4 and IL-10 did not influence synovitis or cartilage degeneration. In contrast, equimolar amounts of the fusion protein attenuated cartilage damage upon repeated joint bleeding, although synovial inflammation was hardly affected. Conclusions Overall, this study shows that the IL4-10 fusion protein prevents blood-induced cartilage damage in vitro and ameliorates cartilage degeneration upon joint bleeding in hemophilic mice.

In silico evaluation of limited blood sampling strategies for individualized recombinant factor IX prophylaxis in hemophilia B patients.

Essentials Individual pharmacokinetic (PK) parameters can be obtained by limited sampling strategies (LSSs). Following 100 IU kg-1 rFIX, LSSs with 1 to 3 samples were evaluated in 5000 simulated subjects. For all LSSs, estimated individual PK parameters showed acceptable bias and precision. One sample between 10 min-3 h and two between 48 h-56 h showed best predictive performance. SUMMARY: Background Patients with severe hemophilia B regularly administer prophylactic intravenous doses of clotting factor IX concentrate to maintain a trough level of at least 0.01 IU mL-1 in order to prevent joint bleeds. Assessment of individual pharmacokinetic (PK) parameters allows individualization of the recombinant factor IX (rFIX) dose. Aim To evaluate the predictive performance of limited sampling strategies (LSSs) with one to three samples to estimate individual PK parameters of rFIX. Methods Monte Carlo simulations were performed to obtain 5000 concentration-time profiles by the use of population PK parameters for rFIX from literature. Eleven LSSs were developed with one, two or three samples taken within an 80-h interval following administration of 100 IU kg-1 rFIX. Clearance (CL), half-life (t1/2 ), time to 1% and steady-state distribution volume (Vss ) were estimated for each simulated individual by the use of Bayesian analysis. Results For each LSS, average bias was small for CL (range - 1.5% to 1.4%), t1/2 (range - 4.5% to - 0.7%), time to 1% (range - 2.9% to 0%), and Vss (range - 3.7% to 0.3%). Imprecision for these parameters ranged from 6.4% to 11.9%, from 10.3% to 15.6%, from 7.3% to 10.9%, and from 9% to 20.1%, respectively. The best predictive performance was achieved with one sample taken between 10 min and 3 h and two samples taken between 48 h and 56 h after administration of rFIX. Conclusions This study demonstrates that limited sampling strategies, used for individualized dosing of rFIX in hemophilia B patients, can be developed and evaluated by in silico simulation.

Joint assessment in von Willebrand disease. Validation of the Haemophilia Joint Health score and Haemophilia Activities List.

Assessment of clinical outcome after joint bleeding is essential to identify joint damage and optimise treatment, to prevent disability. However, disease-specific tools to assess the musculoskeletal status in patients with von Willebrand disease (VWD) are lacking. We aimed to determine validity and reliability of the Haemophilia Joint Health Score (HJHS) and Haemophilia Activities List (HAL) in patients with Von Willebrand disease (VWD). Ninety-six patients with VWD were included (mean age 46 years) of whom 27 had more than five documented joint bleeds. The HJHS was performed in all patients and all patients completed the HAL and Impact on Participation and Autonomy (IPA) questionnaires. Health-related quality of life (SF36) results were obtained from the prior 'Willebrand in the Netherlands' study. Joint X-rays of knees, elbows and ankles were scored according to Pettersson (PS). Internal consistency of the HJHS (Cronbach's α (α)=0.75) and HAL (α=0.89) were good. Inter-observer agreement of the HJHS was good (ICC 0.84; Limits of Agreement ± 10.3). The HJHS showed acceptable correlation with the X-ray PS (Spearman's r (rs)>0.60 all joints) and HAL (rs=0.71). The HAL also showed acceptable correlation with the SF36 physical functioning (rs=0.65) and IPA (rs=0.69). Hypothesis testing showed adequate discriminative power of both instruments: in patients with a history of >5 versus ≤ 5 joint bleeds (median HJHS 10 vs 2 (p<0.01); median HAL 77 vs 98 (p<0.01)), independent from age. In conclusion, both the HJHS and HAL are feasible to assess clinical outcome after joint bleeds in VWD.

Serological biomarkers detect active joint destruction and inflammation in patients with haemophilic arthropathy.

INTRODUCTION: Progressive arthropathy caused by recurrent joint bleeds is a severe complication in haemophilia. AIM: We investigated whether biomarkers of cartilage and bone degradation, and inflammation were altered in haemophilia patients and whether these biomarkers could identify haemophilia patients with arthropathy. METHODS: Serum from 35 haemophilia patients with varying degrees of arthropathy and 43 age- and gender-matched control subjects were analysed. Biomarkers of cartilage degradation (C2M, COMP, CTX-II, ADAMTS5), cartilage formation (PRO-C2), bone formation (PINP), bone resorption (CTX-I) and inflammation (hsCRP, CRPM) were measured by ELISA. Arthropathy was assessed by radiological evaluation (Pettersson score) and physical examination (Gilbert score). RESULTS: In patients with haemophilia, cartilage degradation, measured by C2M, CTX-II and COMP, was increased by 25% (P < 0.05) compared with control subjects. Levels of the cartilage degradation enzyme, ADAMTS5, were 10% lower in haemophilia patients (P < 0.05). Bone formation (PINP) was reduced by 25% (P < 0.05) in haemophilia patients, whereas bone resorption (CTX-I) was increased by 30% (P < 0.001). Acute inflammation (hsCRP) was increased by 50% (P < 0.01), whereas chronic inflammation (CRPM) was decreased by 25% (P < 0.0001). The hsCRP/CRPM ratio was 60% higher (P < 0.001) in haemophilia patients relative to control subjects. A biomarker panel combining C2M, CRPM, and ADAMTS5 could distinguish haemophilia patients from control subjects with 85.3% accuracy (P < 0.0001). We found no strong correlation between biomarkers and radiological and physical examination of the joint. CONCLUSION: Biomarkers detect increased cartilage and bone degradation, and altered inflammatory activity in haemophilia patients with arthropathy. These biomarkers could potentially be used to identify patients with progressing joint disease.

Subchondral haematoma.

Haemophilic arthropathy is a complex multifactorial disorder that poses significant challenges to both the treating haematologist and arthroplasty surgeon. Its pathogenesis is incompletely understood. Recent literature has concentrated on the toxic effects of iron and the characteristic inflammatory synovitis. Discussion of the role of subchondral bleeding in joint damage has been neglected. A case of haemophilic arthropathy with extensive evidence of subchondral bleeding and related osteochondral destruction is presented. RESULT: The relevance of this mechanical pathway in the future management of haemophilic arthropathy is discussed with reference to recent literature. CONCLUSION: Clinicians should consider its importance when deciding whether to manage patients expectantly or with prophylactic factor replacement.

Factor VIII Activity and Inhibitor Assays in the Diagnosis and Treatment of Hemophilia A.

The treatment of a patient with a factor VIII (FVIII) deficiency can be complicated. The mainstay of therapy is factor replacement. Replacement therapy can be given prophylactically, with the goal of decreasing hemarthroses and spontaneous hemorrhage, or on-demand for the bleeding patient. Intra- and interindividual variability in a patient's response to treatment has been well documented by the differences in observed half-lives of infused product. Although weight-based dosing nomograms are most often used, personalized therapies are coming into use to ease the burden of therapy and cost. The most significant complication of treatment is the formation of inhibitors to FVIII. The role of the laboratory is to provide results for FVIII activity that accurately reflects a patient's baseline level and response to treatment. However, factor activity assays have many components that can contribute to result variability. These include the methodology and reagent components used to measure the FVIII activity, the reference standard employed, algorithm used to interpret the dilutions, and the replacement factor being measured. An understanding of assay variables and their impact will assist in providing accurate factor activity results and appropriate patient care.

Changing Paradigm of Hemophilia Management: Extended Half-Life Factor Concentrates and Gene Therapy.

Management of hemophilia has evolved significantly in the last century-from recognition of the causative mechanism in the 1950s to commercially available clotting factor concentrates in the 1960s. Availability of lyophilized concentrates in the 1970s set the stage for home-based therapy, followed by introduction of virally attenuated plasma-derived, and then recombinant factor concentrates in the 1980s and 1990s, respectively. The subsequent years saw a paradigm shift in treatment goals from on-demand therapy to prophylactic factor replacement starting at an early age, to prevent hemarthrosis becoming the standard of care for patients with severe hemophilia. In the developed world, the increasing use of home-based prophylactic regimens has significantly improved the quality of life, and life expectancy of patients with severe hemophilia. Seminal developments in the past 5 years, including the commercial availability of extended half-life factor concentrates and the publication of successful results of gene therapy for patients with hemophilia B, promise to further revolutionize hemophilia care over the next few decades. In this review, we summarize the evolution of management for hemophilia, with a focus on extended half-life factor concentrates and gene therapy.