The higher prevalence of missense mutations in hemophilia B compared to hemophilia A could be important in determining a milder clinical phenotype in patients with severe hemophilia B

Introduction. Prophylaxis with factor concentrates reduces bleeding events and improves quality of life for adults and children with severe hemophilia. However, the optimal dosing and infusion frequency is not yet established. Integration of PK data into decision making is gaining support, in particular at the transition between conventional and EHL products. Here we report about 29 PK data of patients affected by hemophilia treated at our centre since childhood. Improved quality of life was our first aim, supposed that decreasing frequency of infusions or increasing the target through factor level allows a more active life without increased risk of bleeding. Patients' characteristics and methods. 18 patients (62%) were ≤ 18 years of age at PK time. 16 were affected by severe hemophilia A, 5 by moderate hemophilia A, 6 by severe hemophilia B and 2 by moderate hemophilia B. At PK time, 28 patients were on prophylaxis and 1 was on demand with recombinant factor IX. Median age at onset of prophylaxis was 9 years (range 3 months-38 years). Genetic assessment was available in 24 patients. Of these, 37.5% and 62.5% were carriers of null and not null mutations respectively. 4 patients were undergone to PK with standard products (1 Octocog alfa, 1 Simoctocog alfa, 1 Octocog alfa-Kovaltry®, 1 Turoctocog alfa) in order to define timing and dosage of successive infusions, while 25 patients switched to EHL factors (15 Efmoroctocog alfa, 2 Ionoctocog alfa, 7 Albutrepenonacog alfa, 1 Eftrenonacog alfa). In 15 patients a population-based PK (popPK) according to WAPPS-Hemo program was also performed. The annualized bleeding rate (ABR) was counted from patient's home bleeding records for one year before PK until now. Results. According to PK data, 21 patients (75%) decreased infusion frequency (100% hemophilia B and 67% hemophilia A patients). The remaining 7 hemophilia A patients maintained the same timing in order to increase the through factor level. Notably, 1 hemophilia B patient switched from on demand treatment to prophylaxis with EHL product due to the more acceptable schedule. 66% of null mutation patients and 73% of not null mutation patients decreased timing. Of 28 patients available at follow-up, 32%, 50% and 18% decreased, increased and maintained the same annual average factor consumption/kg, respectively. All patients had a good adherence after switch. In particular, the on demand patient started a regular prophylaxis with optimal compliance. ABR displayed a reduction with a median of 0 (range 0-5) after PK analysis compared to 1 (range 0-12) before the switch. Full PK vs popPK data obtained using at least two individual PK sampling points were almost similar. Conclusions. Our results remark the necessity of PK study especially in children due to the inter-individual variability independent of genetic assessment. Regarding factor IX, PK allowed us to propose timing even longer than that recommended by prescribing indications resulting in a better personalized prophylaxis. Moreover, our study demonstrates that a full PK analysis is feasible also in children. However, given similar results, popPK could be more feasible in most patients. Regarding consumption, the reduction of only 32% of patients reflects our aim to maintain a high safety profile in an active pediatric population. Nevertheless, the mean annualized consumption was just 0.6-fold increased in the remaining patients. This approach led us to further reduce ABR and in some cases to obtain a persistent no-bleeding status even with a full active life. Disclosures No relevant conflicts of interest to declare.

Download Full-text

F8 gene mutation type and inhibitor development in patients with severe hemophilia A: systematic review and meta-analysis

Blood ◽

10.1182/blood-2011-09-379453 ◽

2012 ◽

Vol 119 (12) ◽

pp. 2922-2934 ◽

Cited By ~ 195

Author(s):

Samantha C. Gouw ◽

H. Marijke van den Berg ◽

Johannes Oldenburg ◽

Jan Astermark ◽

Philip G. de Groot ◽

...

Keyword(s):

Systematic Review ◽

Gene Mutation ◽

Hemophilia A ◽

High Titer ◽

Meta Analysis ◽

Gene Mutations ◽

Secondary Outcome ◽

Missense Mutations ◽

Severe Hemophilia ◽

Inhibitor Development

Abstract This systematic review was designed to provide more precise effect estimates of inhibitor development for the various types of F8 gene mutations in patients with severe hemophilia A. The primary outcome was inhibitor development and the secondary outcome was high-titer-inhibitor development. A systematic literature search was performed to include cohort studies published in peer-reviewed journals with data on inhibitor incidences in the various F8 gene mutation types and a mutation detection rate of at least 80%. Pooled odds ratios (ORs) of inhibitor development for different types of F8 gene mutations were calculated with intron 22 inversion as the reference. Data were included from 30 studies on 5383 patients, including 1029 inhibitor patients. The inhibitor risk in large deletions and nonsense mutations was higher than in intron 22 inversions (pooled OR = 3.6, 95% confidence interval [95% CI], 2.3-5.7 and OR = 1.4, 95% CI, 1.1-1.8, respectively), the risk in intron 1 inversions and splice-site mutations was equal (pooled OR = 0.9; 95% CI, 0.6-1.5 and OR = 1.0; 95% CI, 0.6-1.5), and the risk in small deletions/insertions and missense mutations was lower (pooled OR = 0.5; 95% CI, 0.4-0.6 and OR = 0.3; 95% CI, 0.2-0.4, respectively). The relative risks for developing high titer inhibitors were similar.

Download Full-text

Most Factor VIII B Domain Missense Mutations Are Unlikely to Be Causative Mutations for Hemophilia A: Implications for Factor VIII Genetic Analysis

Blood ◽

10.1182/blood.v112.11.513.513 ◽

2008 ◽

Vol 112 (11) ◽

pp. 513-513

Author(s):

Kyoichi Ogata ◽

Steven W. Pipe

Keyword(s):

Amino Acid ◽

Factor Viii ◽

Hemophilia A ◽

Coagulation Factor ◽

Causative Mutation ◽

Factor V ◽

Missense Mutations ◽

Severe Hemophilia ◽

Single Chain

Abstract Hemophilia A results from the quantitative or qualitative deficiency of coagulation factor VIII (FVIII). FVIII is synthesized as a single-chain polypeptide of approximately 280 kDa with the domain structure A1-A2-B-A3-C1-C2. Whereas the A and C domains exhibit ~40% amino acid identity to each other and to the A and C domains of coagulation factor V, the B domain is not homologous to any known protein and is dispensable for FVIII cofactor activity. Missense mutations in the FVIII B domain have been described in patients with variable phenotypes of hemophilia A. According to the NCBI SNPs (single nucleotide polymorphism) database, 22 SNPs are reported within FVIII, 11 of which occur within the B domain. FVIII B domain variant D1241E has been reported as a missense mutation associated with mild or severe hemophilia A, yet this mutation is also present in the NCBI SNPs database. We hypothesize that D1241E and most other reported B domain missense mutations are not the causative mutation for hemophilia A in these patients but represent SNPs or otherwise non-pathologic mutations. To investigate this, we analyzed 7 B domain missense mutations that were previously found in hemophilia A patients (T751S, V993L, H1047Y, D1241E, T1353A, P1641L and S1669L). Comparative analysis showed that the amino acids at these positions are not conserved in all species and in some cases, the amino acid substitution reported in hemophilia patients is represented in the native sequence in other species. Analysis with PolyPhen Software showed that only H1047Y mutation was considered as “possibly damaging”, while the others were considered as “benign”. To investigate this further, we constructed seven plasmid vectors containing these B domain missense mutations. The synthesis and secretion of FVIII wild-type (WT) and these seven mutants were compared after transient DNA transfection into COS-1 monkey cells in vitro. Analysis of the FVIII clotting activity and antigen levels in the conditioned medium demonstrated that all mutants had FVIII activity and antigen levels similar to FVIII WT. Further, FVIII WT, H1047Y and D1241E mutants were introduced into a FVIII exon 16 knock-out mouse model of hemophilia A by hydrodynamic tailvein injection in vivo. The mouse plasma was analyzed at 24 hrs for activity and antigen expression. Mutants H1047Y and D1241E expressed at 211 mU/mL and 224 mU/mL activity with FVIII antigen levels of 97 ng/mL and 118 ng/mL, respectively, similar to FVIII WT. These results suggested that H1047Y and D1241E mutants did not lead to impairments in secretion or functional activity. We conclude that most missense mutations within the FVIII B domain would be unlikely to lead to severe hemophilia A and that the majority of such missense mutations represent polymorphisms or non-pathologic mutations. Investigators should search for additional potentially causative mutations elsewhere within the FVIII gene when B domain missense mutations are identified.

Download Full-text

The EPIC Study: A Clinical Trial To Assess Whether Early Low Dose Prophylaxis In The Absence Of Immunological Danger Signals Reduces Inhibitor Incidence In Previously Untreated Patients (PUPs) With Hemophilia A

Blood ◽

10.1182/blood.v122.21.576.576 ◽

2013 ◽

Vol 122 (21) ◽

pp. 576-576 ◽

Cited By ~ 4

Author(s):

Guenter Auerswald ◽

Karin Kurnik ◽

Jan Blatny ◽

Armin J Reininger

Keyword(s):

Research Funding ◽

Low Dose ◽

Hemophilia A ◽

Venous Access ◽

Patient Specific ◽

Missense Mutations ◽

Severe Hemophilia ◽

Prophylactic Regimen ◽

Inhibitor Development ◽

Danger Signals

Abstract Background Inhibitor development is a complex, multifactorial immune response involving both patient-specific and treatment-related factors. Of the known risk factors, intensive treatment at an early age has been shown to be significant, and clinical observations have suggested that early prophylaxis (i.e. first exposure to FVIII in the absence of a bleed in the first year of age) may protect patients from inhibitor development by inducing FVIII tolerance. Aim This study aimed to assess prospectively if a once-weekly, low-dose prophylactic regimen started before 1 year of age and before the onset of a severe bleeding phenotype (i.e. joint bleed), together with the minimization of immunological danger signals, could reduce the incidence of inhibitor formation in PUPs with severe and moderately severe hemophilia A to 15% or less. Methods The EPIC study was a Phase 3b, prospective, single arm, historically-controlled, international multicenter study to assess the incidence rate of inhibitor formation in PUPs with severe and moderately severe hemophilia A during the first 50 exposure days (EDs) of treatment with ADVATE starting with a once-weekly, low-dose (ADVATE 25 IU/kg once weekly), prophylactic regimen. If clinically indicated, it was permissible to increase the frequency of dosing to 2 or 3 times per week. In addition, infusions during the first 20 EDs had to be given 3 to 4 days before or after any vaccinations, which had to be given subcutaneously, not intramuscularly; infusions had to be avoided if the subject had high fever (above 38°C [100°F]). Main enrolment criteria were: severe and moderately severe hemophilia A (FVIII ≤2%), age <1 year, ≤3 EDs to any FVIII-containing product used for treatment of minor bleeds or for precautionary infusions following injury, adequate venous access (without need for central venous access device), no life-threatening conditions (intracranial hemorrhage, severe trauma) or requirement for surgery at the time of enrollment, no evidence of inhibitor ≥0.6 BU in Nijmegen-modified Bethesda assay at study start, no hemostatic defect other than hemophilia A, no clinically significant chronic disease other than hemophilia A,. Information about type of FVIII gene defect was obtained in 17 subjects. FVIII inhibitor tests were performed at screening, at study infusion #3, 6, 10, 15, 20, 30, 40, and 50, and at any other time point if an inhibitor was suspected. Positive inhibitor testing had to be confirmed by 2 positive inhibitor tests on samples drawn at least 1 week apart. Results A total of 22 subjects were enrolled in the study. Of 20 subjects who met all entry criteria, 19 received treatment; of these, all had severe hemophilia A (FVIII<1%). At study entry 11 of these 19 patients were never exposed to FVIII before (PUPs), while the remaining 8 patients had been treated with FVIII concentrates before. FVIII gene mutation analysis revealed intron 22 inversions in 8 out of 17 subjects, hemizygous missense mutations resulting in a stop-codon in 2 subjects, frame-shift mutations in 2 subjects, and hemizygous missense mutations in 5 subjects. A total of 8 subjects developed a confirmed inhibitor: 2 of these 8 subjects had only borderline positivity at inhibitor testing (never above 0.6 BU) with absence of any anti-FVIII antibodies (IgG, IgA, IgM and IgG subclasses) as tested by ELISA. Thus incidence of inhibitors >0.6 BU in PUPs were 27%. A total of 67 major protocol deviations (PD) were reported in 15 patients: 44 PDs of these were reported in 10 subjects and were related to the treatment regimen and therefore have contrasted with the protocol intention, which was to minimize immunological danger signals and low dose prophylactic regimen. As a result of the observed inhibitor incidence the study was terminated based on futility analysis, i.e. the probability to achieve the primary end-point of inhibitor rate reduction to ≤15%. Details on inhibitor patients will be presented. Discussion The EPIC study showed no safety issue as confirmed by the Data Safety Monitoring Board. To align treatment decisions in the presence of danger signals (which are not completely avoidable in children around 1 year of age) with a demanding study protocol was found to be challenging. Thus the hypothesis that an early low dose prophylaxis in the absence of immunological danger signals might reduce inhibitor incidence in PUPs with hemophilia A could neither be verified nor disproved within this study. Disclosures: Auerswald: Novo Nordisk: Consultancy, Research Funding; Biotest: Consultancy, Research Funding; CSL-Behring: Consultancy, Research Funding; Bayer: Consultancy, Research Funding; Baxter: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding. Kurnik:Baxter: Consultancy, Research Funding; Bayer: Consultancy, Research Funding; Biotest: Consultancy, Research Funding; CSL-Behring: Consultancy, Research Funding; Novo Nordisk: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding. Blatny:Baxter: speaker fee Other. Reininger:Baxter Innovations GmbH: Employment.

Download Full-text

Real World Use of Extended Half-Life Products and the Impact on Bleeding Events and Joint Health in the United States

Blood ◽

10.1182/blood-2018-99-113956 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 1195-1195 ◽

Cited By ~ 1

Author(s):

Lynn M. Malec ◽

Char M Witmer ◽

Julie Jaffray ◽

Peter A. Kouides ◽

Kristina M. Haley ◽

...

Keyword(s):

Board Of Directors ◽

Real World ◽

Research Funding ◽

Hemophilia A ◽

Advisory Board ◽

Hemophilia B ◽

Severe Hemophilia ◽

Bleeding Events ◽

On Demand ◽

Joint Health

Abstract Background : The hemophilia treatment landscape has evolved substantially in the last several years with the approval of extended half-life (EHL) products which reduce the burden of prophylaxis. Data reported from the American Thrombosis and Hemostasis Network (ATHN) as of June 2017 indicate that 21% of patients with moderate or severe hemophilia A, and 42% of patients with moderate or severe hemophilia B, receive prophylaxis utilizing an EHL. As new treatments become available and are adopted into practice, it is important to recognize the need for evaluation of efficacy, safety, and economic impact of their use outside of the clinical trial setting. We aimed to characterize the real world impact of EHL products by collecting detailed information on bleeding rates, joint health and quality of life amongst patients cared for at ATHN-affiliated Hemophilia Treatment Centers. We hypothesized that use of EHL products were utilized in at least 30% of patients and would lead to decreased ABRs and improved joint health. To date 67 of a planned 135 subjects have been enrolled, constituting this interim analysis. Methods:Subjects were recruited from seven U.S. Hemophilia Treatment Centers. Subjects with severe hemophilia A or B ≤ 30 years of age on prophylaxis or demand therapy were eligible for enrollment. Subjects excluded from study were those with a recent joint bleed (within the last 2 weeks) or those unwilling to complete all elements of the study. Data were collected during a one-time encounter concurrent with an appointment for clinical evaluation, including demographic information, treatment regimen, product type, frequency, location and severity of all bleeds, Hemophilia Joint Health Scores (HJHS), and Quality of life (QoL). Bleeding rates in subjects receiving prophylaxis were compared with those receiving on demand therapy by type treatment, EHL vs standard half-life (SHL), and by hemophilia type. Severity of bleeding events (mild, moderate, or severe) and HJHS were compared by prophylaxis groups. Results: A total of 67 patients were enrolled and eligible for analysis. This included 58 subjects with severe hemophilia A, and 9 subjects with severe hemophilia B. The mean age of the cohort was 15 years (median 12 years, IQR 8 - 21 years). For these patients whose race information was known, 89.1% were Caucasian, 3.3% African-American, 3.3% Asian, and 4.7% were of mixed or 'other' race. Eleven out of 61 (18.0%) subjects with known ethnicity were Hispanic. Among 59 patients whose treatment type were available, the majority were on prophylaxis (n=53; 89.8%) as compared to on demand therapy (n=6; 10.2%). The average annualized bleeding rate (ABR) was 2.8 amongst all individuals. As expected, the ABR was substantially lower in those receiving prophylaxis (ABR=1.0) as compared to on demand therapy (ABR=18.6) (p<0.001). Additionally, HJHS in those receiving prophylaxis was lower (mean HJHS= 3.9), meaning less evidence of joint damage, than in those receiving demand therapy (mean HJHS= 8.8) (p=0.162). For patients with severe hemophilia A, the ABR was lower in those individuals receiving EHL (ABR= 0.5) versus SHL (ABR= 1.5), although this did not reach statistical significance (p=0.136). All subjects with severe hemophilia B enrolled to date receive EHL products (n=9) therefore no comparison of ABR could be made between EHL and SHL products; the ABR in this group was 0.9. In patients with severe hemophilia A, there was a higher HJHS for those receiving EHL (mean HJHS= 7.0) versus those receiving SHL (mean HJHS = 2.1) (p=0.053). For patients with severe hemophilia B, all of whom received EHL, the mean HJHS was lower than in the hemophilia A cohort (mean HJHS=1.2). Conclusions: We report real-world bleeding events and joint health in patients with severe hemophilia A and B utilizing EHL and SHL products across a wide U.S. geographic distribution. As anticipated, there is substantial bleed reduction with prophylaxis versus on demand therapy. In our severe hemophilia A cohort, the ABR for patients receiving EHL products was similar to ABRs reported in clinical trials, suggesting clinical trial data may be reflective of real world use. Patients with severe hemophilia A receiving EHL for prophylaxis had a lower ABR than those receiving SHL, although the early impact is not reflected in the HJHS score. Longer follow-up will be necessary to determine the impact of EHL on HJHS. Disclosures Malec: Bioverativ: Research Funding; Bayer: Consultancy; Bioverativ: Consultancy; Shire: Consultancy. Jaffray:Octapharma: Consultancy; Bayer: Consultancy; CSL Behring: Consultancy, Research Funding. Kouides:UniQure: Other: DSMB; Octapharma: Research Funding. Sidonio:Octapharma: Other: Advisory Board; Genentech: Other: Advisory Board, Research Funding; CSL Behring: Other: Advisory Board; Shire: Other: Advisory Board, Research Funding; Novo Nordisk: Other: Advisory Board; Kedrion: Research Funding; Biomarin: Other: Advisory Board; Grifols: Other: Advisory Board, Research Funding; Bioverativ: Other: Advisory Board, Research Funding; Uniqure: Other: Advisory Board. Abshire:CSL: Consultancy; Shire: Consultancy; Novo Nordisk: Other: DSMB. White:Asklepios: Other: Scientific Advisory Board; Novo Nordisk: Consultancy; Shire: Other: Physician Leadership Group; Bayer: Other: GRAC; Bioverativ: Other: DSMB; Biomarin: Other: DSMB; Invitrox: Other: Scientific Advisory Board; Pfizer: Equity Ownership. Ragni:CSL Behring: Research Funding; Biomarin: Membership on an entity's Board of Directors or advisory committees, Research Funding; SPARK: Consultancy, Research Funding; Shire: Research Funding; Bioverativ: Consultancy, Research Funding; Alnylam: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novo Nordisk: Research Funding; Sangamo: Research Funding; MOGAM: Membership on an entity's Board of Directors or advisory committees.

Download Full-text

Plasma Tissue Factor Pathway Inhibitor (TFPI) Levels in Healthy Subjects and Patients with Hemophilia A and B

Blood ◽

10.1182/blood.v126.23.4672.4672 ◽

2015 ◽

Vol 126 (23) ◽

pp. 4672-4672 ◽

Cited By ~ 1

Author(s):

Jian-Ming Gu ◽

Chandra Patel ◽

Katalin Kauser

Keyword(s):

Tissue Factor ◽

Healthy Subjects ◽

Tissue Factor Pathway Inhibitor ◽

Hemophilia A ◽

Hemophilia B ◽

Severe Hemophilia ◽

Capture Assay ◽

Healthy Donors ◽

Tissue Factor Pathway

Abstract BAY 1093884 is a fully human monoclonal antibody against tissue factor pathway inhibitor (TFPI) developed as a potential bypass agent for patients with hemophilia with or without inhibitors. It restores insufficient thrombin burst, leading to stable clot formation in hemophilic conditions in vitro, and effectively stops bleeding in vivo. TFPI is a potent inhibitor of factor Xa (FXa) and the factor VIIa tissue factor complex in the extrinsic pathway. The majority of TFPI is associated with vascular endothelial cells. The mean plasma TFPI concentration in healthy individuals is ~70 ng/mL (1.6 nM) and about 80% of the circulating TFPI is bound to lipoproteins [Dahm, et al. Blood. 2003;101(11):4387-4392; Broze,et al. Front Biosci. 2012;17:262-280]. Some reports indicate that patients with hemophilia B have lower free TFPI levels than patients with hemophilia A, irrespective of phenotypic severity (Tardy-Poncet, et al. Haemophilia 2011;17:312-313). The objective of this study is to determine the plasma TFPI concentration in healthy donors and patients with hemophilia by a newly developed functional TFPI capture assay and to evaluate this assay with inhibition of TFPI by anti-TFPI neutralizing antibody (BAY 1093884) in vitro. A quantitative enzyme-linked immunosorbent assay using FXa as capture agent was developed and validated to measure TFPI levels in human plasma. The assay shows very good precision, accuracy, and reproducibility and should capture all coagulation-relevant forms of TFPI from plasma. Plasma TFPI was determined in 30 healthy donors (15 males and 15 females) and 30 patients with severe hemophilia (hemophilia A [n=12], hemophilia A with inhibitors [n=9], hemophilia B [n=9]). The plasma TFPI levels (mean ± SD) in healthy individuals, patients with severe hemophilia A without and with inhibitors, and severe hemophilia B were 59.5±18.4 ng/mL, 62.9±14.6 ng/mL, 47.3±4.3 ng/mL, and 68.1±8.8 ng/mL, respectively (Table 1). No statistical differences were found based on sex or race (Hispanic, African American, white) in the healthy population and between patients with hemophilia with and without inhibitors. TFPI levels were also not affected by addition of corn trypsin inhibitor (CTI) in citrate plasma. Furthermore, the concentration that inhibits 50% of TFPI levels (IC50) of anti-TFPI antibody (BAY 1093884) was determined to be 4.76 nM in normal human plasma using this assay. In conclusion,plasma TFPI does not appear to be affected by sex or race in healthy subjects, or the deficiency of factor VIII or IX in patients with hemophilia. The functional TFPI capture assay could potentially be used as a pharmacodynamic marker for monitoring plasma TFPI levels after the administration of anti-TFPI antibody and guide dosing strategies. Table 1. Plasma TFPI Levels in Healthy Subjects and Patients With Severe Hemophilia A and B HealthyHuman Donors(n=30) SevereHem A(n=12) Severe Hem AWith inhibitors(n=9) SevereHem B(n=9) TFPI, ng/mL Mean ± SD 59.5±18.4 62.9±14.6 47.3±4.3 68.1±8.8 Hem=hemophilia; TFPI=tissue factor pathway inhibitor. Disclosures Gu: Bayer HealthCare: Employment. Patel:Bayer HealthCare: Employment. Kauser:Bayer HealthCare LLC: Employment.

Download Full-text

Clinical, Instrumental, Serological and Histological Findings Suggest That Hemophilia B May be Less Severe Than Hemophilia A

Blood ◽

10.1182/blood.v126.23.4682.4682 ◽

2015 ◽

Vol 126 (23) ◽

pp. 4682-4682

Author(s):

Giancarlo Castaman ◽

Daniela Melchiorre ◽

Silvia Linari

Keyword(s):

Synovial Tissue ◽

Hemophilia A ◽

Conflicts Of Interest ◽

Severe Disease ◽

Rank Correlation ◽

Mean Value ◽

Hemophilia B ◽

Severe Hemophilia ◽

Chi Square ◽

Spearman’S Rank Correlation

Abstract Background: Recent evidences suggest that patients with severe hemophilia B (HB) may have a less severe disease compared to severe hemophilia A (HA). Objectives: to investigate clinical, radiological, laboratory and histological differences in the arthropathy of severe HA and HB. Patients/Methods: 70 HA and 35 HB patients with at least one joint bleeding were consecutively enrolled. In all patients were assessed: joint bleedings (<10, 10-50, >50), regimen of treatment (prophylaxis/on demand), WFH, Pettersson and ultrasound (US) scores, serum sRANKL and OPG. Expression of RANK, RANKL and OPG was also evaluated in synovial tissue from 18 HA and 4 HB patients. Chi-square test, T-test, Mann-Whitney and Spearman's rank correlation coefficient were performed. Results: The percentage of patients with either 10-50 or >50 hemarthrosis was greater in HA than in HB (p< 0.001 and p = 0.03, respectively); that with <10 hemarthrosis was higher in HB (p < 0.0001). The mean value of WFH (36.6 vs 20.2;p <0.0001) and US scores (10.9 vs 4.3;p <0.0001) were significantly higher in HA patients. Serum OPG and s RANKL were decreased in HA versus HB (p<0.0001 and p=0.006, respectively) and also in HA patients with>50 hemarthrosis. The expression of OPG was markedly reduced in synovial tissue from HA patients. Conclusions: The reduced number of hemarthrosis, the lower WFH and US scores and higher OPG levels in serum and expression in synovial tissue in HB suggest that HB is a less severe disease than HA. OPG reduction seems to play a pivotal role in the progression of arthropathy in HA. Disclosures No relevant conflicts of interest to declare.

Download Full-text

Response: Comparing joint arthroplasties in severe hemophilia A with severe hemophilia B

Blood ◽

10.1182/blood-2009-09-244566 ◽

2009 ◽

Vol 114 (23) ◽

pp. 4907-4908

Author(s):

Giuseppe Tagariello ◽

Alfonso Iorio ◽

Pier M. Mannucci

Keyword(s):

Hemophilia A ◽

Hemophilia B ◽

Severe Hemophilia ◽

Joint Arthroplasties

Download Full-text

Aminoglycoside suppression of nonsense mutations in severe hemophilia

Blood ◽

10.1182/blood-2005-03-1307 ◽

2005 ◽

Vol 106 (9) ◽

pp. 3043-3048 ◽

Cited By ~ 55

Author(s):

Paula D. James ◽

Sanj Raut ◽

Georges E. Rivard ◽

Man-Chiu Poon ◽

Margaret Warner ◽

...

Keyword(s):

Thrombin Generation ◽

Hemophilia A ◽

Aminoglycoside Antibiotic ◽

Bactericidal Effect ◽

Factor Ix ◽

Hemophilia B ◽

Severe Hemophilia ◽

Toxic Agent ◽

Nonsense Mutations ◽

Therapeutic Mechanism

AbstractAminoglycoside antibiotics exhibit their bactericidal effect by interfering with normal ribosomal activity. In this pilot study, we have evaluated the effect of the aminoglycoside antibiotic gentamicin on the factor VIII (FVIII) and IX levels of severe hemophiliacs with known nonsense mutations. Five patients were enrolled and each patient was given 3 consecutive days of gentamicin at a dose of 7 mg/kg intravenously every 24 hours. Two patients (patient no. 1: hemophilia A, Ser1395Stop; and patient no. 5: hemophilia B, Arg333Stop) showed a decrease in their activated partial thromboplastin time (aPTT), an increase in their FVIII (0.016 IU/mL, 1.6%) or FIX (0.02 IU/mL, 2%) levels, and an increase in thrombin generation. The remaining 3 patients (patient no. 2: hemophilia B, Arg252Stop; patient no. 3: hemophilia A, Arg2116Stop; and patient no. 4: hemophilia A, Arg427Stop) showed no response in the aPTTs or factor levels, but one (patient no. 2: hemophilia B, Arg252Stop) showed an increase in the factor IX antigen level (2%-5.5%) that persisted throughout the period of the study and was concordant with an increase in thrombin generation. Gentamicin is unlikely to be an effective treatment for severe hemophilia due to its potential toxicities and the minimal response documented in this report. This study, however, does provide a proof of principle, suggesting that ribosomal interference with a less toxic agent may be a potential therapeutic mechanism for severe hemophilia patients with nonsense mutations.

Download Full-text

Immune Tolerance Induction in 28 Children with Hemophilia Awith Inhibitors.

Blood ◽

10.1182/blood.v108.11.1046.1046 ◽

2006 ◽

Vol 108 (11) ◽

pp. 1046-1046

Author(s):

Michael U. Callaghan ◽

Indira Warrier ◽

Madhvi Rajpurkar ◽

Jeanne Lusher

Keyword(s):

Immune Tolerance ◽

Hemophilia A ◽

Tolerance Induction ◽

Hemophilia B ◽

Recurrent Infections ◽

Severe Hemophilia ◽

Central Venous ◽

Immune Tolerance Induction ◽

Inhibitor Development ◽

Peak Titer

Abstract Aim: To study the characteristics, treatment, and outcome of patients with hemophilia with inhibitors who have undergone immune tolerance induction (ITI) at the Children’s Hospital of Michigan over the past 14 years. Methods: In compliance with local IRB regulations, patient charts and laboratory databases were reviewed and salient data extracted. 28 boys underwent 29 attempts at immune tolerance induction. Results: Hemophilia A 26 boys with severe hemophilia A with inhibitors underwent 27 trials of ITI. In this cohort of 26 patients the average age at which patients developed an inhibitor was 22 months and the average age at start of ITI was 5 years 4 months (range 2 months to 17 years 5 months). The average number of exposure days prior to inhibitor development was 10 (1–47). The average time between development of an inhibitor and initiation of ITI was 43 months, with no difference between those who successfully completed ITI and those who did not. Six patients had low titer inhibitors (0.8–6.5 BU) and successfully completed ITI using a modified low dose ITI regimen of factor infusions 3–7 times per week. 20 of the patients with high titer inhibitors (6.4–1280 BU) were treated with daily infusions of 50–200 units/kg/d of factor VIII (FVIII) products. For ITI, 4 patients received high purity plasma derived FVIII (PD-FVIII) and 21 received recombinant FVIII (rFVIII) and one received both. In patients who became tolerized to FVIII, the average time to achieve an inhibitor titer of 0 Bethesda Units (BU) was 211 days. In those who were unable to achieve tolerance, the average length of the trial was 263 days. 21 of the ITI trials employed a central venous catheter and in 5 patients ITI was stopped after removal of the line because of recurrent infections. 14 boys received FEIBA, rFVIIa, or porcine FVIII for bleeding episodes during ITI; 8 of them failed ITI and one is still on therapy. Seven trials of ITI were in Caucasian patients (26 %), 17 in African American (AA) (63 %), and 3 in Middle Eastern patients (11 %). 19 patients achieved complete tolerance (73 %), 6 patients failed (23 %), one failed twice, and one patient continues on therapy. All but 2 patients who successfully completed ITI went on prophylaxis with FVIII. All patients who successfully completed ITI have maintained tolerance with a mean follow-up of 101 months (range 7–168). Table I: Hemophilia A Failed ITI Successful ITI *One still ongoing Number of trials* 7 (23 %) 19 (73 %) African Americans 7 (41 %) 10 (59 %) Non-AA 0 10 (100 %) Historical Peak Titer (mean) 345 BU 47 BU Titer at Start of ITI (mean) 62 BU 5 BU Peak Titer on ITI (mean) 168 BU 46 BU Age at inhibitor development (mean) 26 months 12 months ITI with PD-FVIII 1 4 ITI with rFVIII 7 15 Hemophilia B During this time period, 2 boys with severe hemophilia B underwent ITI. Both had severe allergic reactions at the time of inhibitor development; both underwent desensitization successfully but both failed ITI. Both started ITI with plasma derived factor nine at age 15 months. One developed nephrotic syndrome while on ITI. Conclusions: Most patients with Hemophilia A were able to achieve and maintain tolerance (73%). Higher titer inhibitors, hemophilia B, younger age at development of inhibitor, AA race and treatment of bleeds with bypass agents or porcine factor while on ITI were risk factors for ITI failures. Loss of central venous access with recurrent infections was also a common reason for ITI failure.

Download Full-text