Risk Factors for High-Titer Inhibitor Development in Children with Hemophilia A: Results of a Cohort Study

Among the discussed risk factors for high-titre inhibitor (HRI) development in patients with hemophilia A (HA) are high dose FVIII replacement therapy and use of recombinant FVIII concentrates (rFVIII). The aim of this study was to evaluate the aforementioned risk factors for HRI development in children with hemophilia A ≤2%. About 288 ascertained PUPs (Israel and Germany) were followed after initial HA diagnosis over 200 exposure days. Inhibitor-free survival, hazard ratios (HR), and 95% confidence intervals (CIs) were calculated. Adjustment was performed for factor VIII concentrates, median single dose over the first three months of treatment, first FVIII administration before the age of three months, presence of risk HA gene mutations, “intensive treatment moments” and “year of birth” (proxy for different treatment periods). HRI occurred in 71/288 children (24.7%). In multivariate analysis adjusted for “year of birth”, underlying risk gene mutations (HR/CI: 2.37/1.40–3.99), FVIII dose, measured per one IU increase per kgbw (HR/CI: 1.05/1.04–1.07), and first FVIII administration before the age of three months showed a significant impact on HR development. The risk of HRI development was similar for recombinant or plasmatic FVIII products. Children at risk should be treated with carefully calculated lower dose regimens, adapted to individual bleeding situations.

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Rurioctocog Alfa Pegol Use in Immune Tolerance Induction: Interim Results from an Open-Label Multicenter Clinical Trial in Previously Untreated Patients with Severe Hemophilia a

Blood ◽

10.1182/blood-2021-146143 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 3185-3185

Author(s):

Robert F. Sidonio ◽

Alexis A. Thompson ◽

Flora Peyvandi ◽

Canan Albayrak ◽

Seoh Leng Yeoh ◽

...

Keyword(s):

Research Funding ◽

Hemophilia A ◽

High Titer ◽

Tolerance Induction ◽

High Dose ◽

Severe Hemophilia ◽

Publicly Traded ◽

Open Label ◽

Fviii Inhibitor ◽

Recombinant Fviii

Abstract Background The development of inhibitors to exogenous factor VIII (FVIII) is a serious treatment complication in patients with hemophilia A. Immune tolerance induction (ITI) is the only proven method for the eradication of FVIII inhibitors. This prospective, multicenter, open-label, phase 3 study (NCT02615691) is being conducted to determine the safety, immunogenicity, and efficacy of the extended half-life (EHL) recombinant FVIII rurioctocog alfa pegol (Adynovate ®; Baxalta US Inc., a Takeda company, Lexington, MA, USA) in previously untreated patients (PUPs) with severe hemophilia A. The data presented here aims to evaluate the efficacy and safety of ITI therapy with rurioctocog alfa pegol in patients who developed FVIII inhibitors. Methods Eligible patients were ˂6 years of age with severe hemophilia A (FVIII <1%) and <3 exposure days (ED) to rurioctocog alfa pegol, octocog alfa, or plasma transfusion at any time prior to screening. Patients with detectable FVIII inhibitory antibodies at screening or a history of FVIII inhibitors prior to screening (≥0.6 Bethesda units [BU]) were excluded from the study. Patients received intravenous rurioctocog alfa pegol as prophylaxis (25-50 IU/kg, up to 80 IU/kg ≥1 × weekly) and/or on-demand therapy (10-50 IU/kg, up to 80 IU/kg depending on bleed severity). Patients who developed a high-titer FVIII inhibitor (>5.0 BU) or low-titer FVIII inhibitor (≥0.6 BU to ≤ 5.0 BU) plus poorly controlled bleeding despite increased FVIII doses and/or bypassing agents, were eligible for ITI therapy. Dosing for ITI therapy ranged between 50 IU/kg 3 × weekly (low dose) and 100-200 IU/kg daily (high dose) at investigator discretion. This protocol-specified interim analysis was conducted after 50 patients had completed ≥50 EDs without developing confirmed inhibitors to rurioctocog alfa pegol or had developed a confirmed FVIII inhibitor at any time. The data cut-off was 30 August 2019. The primary endpoint of this study was the success rate of ITI with rurioctocog alfa pegol. Success was defined as an inhibitor titer persistently <0.6 BU, FVIII incremental recovery (IR) ≥66% of baseline following 84- to 96-hour wash-out, and FVIII half-life ≥6 hours (dependent on protocol version). Secondary endpoints included the rates of partial success and failure of ITI, and annualized bleeding rate (ABR) during ITI. The number and percentage of patients reporting adverse events (AEs) and serious AEs (SAEs) were recorded for patients treated with ITI. Informed consent and ethics approval were obtained. Results As of the data cut-off, 59 (73.8%) of 80 enrolled patients had received ≥1 dose of rurioctocog alfa pegol; 18 patients did not meet the eligibility criteria (screen failures) and 4 discontinued prior to treatment. 10 patients developed an inhibitor to rurioctocog alfa pegol (high titer: n=5; low titer: n=5), of these, 6 patients were enrolled to receive ITI and only 5 of these (83.3%) actually received ≥1 dose of rurioctocog alfa pegol for the treatment of FVIII inhibitors (low dose: n=3; high dose: n=2). Of these 5 patients, 1 completed high-dose ITI therapy and this was successful (based on negative inhibitor titer and IR ≥66% of baseline). The remaining 4 patients were continuing in the study at the time of the data cut-off. Of the 5 patients who received ≥1 dose of ITI, 4 (80.0%) had a total of 17 AEs, 3 (60.0%) experienced 8 SAEs, and 1 experienced a treatment-related SAE of FVIII inhibition. It is important to note that the onset date of FVIII inhibitor development in this patient occurred prior to initiation of ITI. One patient experienced 2 catheter-related AEs, both of which resolved, and no patients experienced thrombotic AEs, study procedure-related AEs, or AEs leading to discontinuation of treatment. Discussion This is the first prospective study of the EHL recombinant FVIII rurioctocog alfa pegol for the treatment of PUPs with severe hemophilia A. These preliminary results demonstrate that rurioctocog alfa pegol has a safety profile consistent with previous studies. In addition, these interim data suggest that using a high-dose regimen for ITI therapy is potentially efficacious in PUPs who have developed FVIII inhibitors, although only 1 patient had completed ITI at the time of this interim analysis. Disclosures Sidonio: Pfizer: Consultancy; Octapharma: Consultancy, Research Funding; Catalyst: Consultancy; Novo Nordisk: Consultancy; Bayer: Consultancy; Guardian Therapeutics: Consultancy; Genentech: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Biomarin: Consultancy. Thompson: Global Blood Therapeutics: Current equity holder in publicly-traded company; CRISPR Therapeutics: Research Funding; Vertex: Research Funding; Editas: Research Funding; Graphite Bio: Research Funding; Novartis: Research Funding; Agios: Consultancy; Beam: Consultancy; Celgene/BMS: Consultancy, Research Funding; Biomarin: Research Funding; Baxalta: Research Funding; bluebird bio, Inc.: Consultancy, Research Funding. Peyvandi: Bioverativ: Honoraria; Sanofi: Consultancy, Honoraria; Sobi: Consultancy, Honoraria; Spark: Honoraria; Takeda: Honoraria; Roche: Honoraria; Grifols: Honoraria. Yeoh: Grifols: Honoraria; Roche: Honoraria; Pfizer: Honoraria; Takeda: Honoraria. Lam: Takeda: Consultancy, Honoraria; Roche: Honoraria; Bayer: Honoraria; Pfizer: Consultancy, Honoraria. Maggiore: IQVIA: Current Employment. Engl: Takeda: Current equity holder in publicly-traded company; Baxalta Innovations GmbH, a Takeda company: Current Employment. Allen: Takeda: Current equity holder in publicly-traded company; Takeda Development Center Americas, Inc.: Current Employment. Tangada: Takeda Development Center Americas, Inc: Current Employment; Takeda: Current equity holder in publicly-traded company.

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Efficacy of rFVIIIFc for First-Time Immune Tolerance Induction (ITI) Therapy: Final Results from the Global, Prospective VerITI-8 Study

Blood ◽

10.1182/blood-2021-155156 ◽

2021 ◽

Vol 138 (Supplement 2) ◽

pp. LBA-5-LBA-5

Author(s):

Lynn Malec ◽

An Van Damme ◽

Anthony Chan ◽

Mariya Spasova ◽

Nisha Jain ◽

...

Keyword(s):

Half Life ◽

Stock Options ◽

Research Funding ◽

Hemophilia A ◽

High Titer ◽

High Dose ◽

Severe Hemophilia ◽

First Time ◽

Inhibitor Titer ◽

Privately Held

Abstract Introduction: Inhibitor development is a major complication of factor VIII (FVIII) replacement therapy, affecting approximately 30% of people with severe hemophilia A (Peyvandi et al Lancet 2016). Inhibitor eradication is the standard of care to restore responsiveness to FVIII; however, ITI regimens often require frequent high-dose factor injections over a long period (DiMichele et al Haemophilia 2007; Carcao et al Haemophilia 2021). Median (interquartile range [IQR]) time (months) to negative titer in the International ITI Study with high-dose FVIII was 4.6 (2.8-13.8) (n=31); negative titer to normal recovery was 6.9 (3.5-12.0) (n=23); and normal recovery to tolerance was 10.6 (6.3-20.5) (n=22) (Hay and DiMichele Blood 2012). Recombinant factor VIII Fc fusion protein (rFVIIIFc) is an extended half-life (EHL) FVIII that showed potential benefits for ITI in retrospective clinical data and case reports (Malec et al Haemophilia 2016; Groomes et al Pediatr Blood Cancer 2016; Carcao et al Haemophilia 2021). VerITI-8 (NCT03093480) is the first prospective study of rFVIIIFc in first-time ITI and follows on from the reITIrate (NCT03103542) study of rFVIIIFc for rescue ITI (Königs et al Res Pract Thromb Haemost, ISTH 2021). Aim: Describe outcomes in the verITI-8 study of first-time ITI with rFVIIIFc over 48 weeks in subjects with severe hemophilia A and high-titer inhibitors. Methods: VerITI-8 is a prospective, single-arm, open-label, multicenter study exploring efficacy of rFVIIIFc for first-time ITI in people with severe hemophilia A with high-titer inhibitors. Initial screening was followed by an ITI period in which all subjects received rFVIIIFc 200 IU/kg/day until tolerization or 48 weeks had elapsed (Figure). This was followed by tapered dose reduction to standard prophylaxis and follow-up. Key inclusion criteria included males with severe hemophilia A, high-titer inhibitors (historical peak ≥5 Bethesda units [BU]/mL), and prior treatment with any plasma-derived or recombinant standard half-life or EHL FVIII. Key exclusion criteria included coagulation disorder(s) other than hemophilia A and previous ITI. The primary endpoint was time to tolerization (successful ITI) with rFVIIIFc defined by inhibitor titer <0.6 BU/mL, incremental recovery (IR) ≥66% of expected IR (IR ≥1.32 IU/dL per IU/kg) (both at 2 consecutive visits), and t ½ ≥7 hours (h) within 48 weeks. Secondary endpoints included number of subjects achieving ITI success, annualized bleed rates (ABR), and adverse events (AEs). Results: Sixteen subjects were enrolled and received ≥1 rFVIIIFc dose. Median (range) age at baseline was 2.1 (0.8-16.0) years, and historical peak inhibitor titer was 22.4 (6.2-256.0) BU/mL (Table). Twelve (75%), 11 (69%), and 10 (63%) subjects, respectively, achieved a negative inhibitor titer, an IR >66%, and a t½ ≥7 h (ie, tolerance) within 48 weeks. Median (IQR) times in weeks to achieve these markers of success were 7.4 (2.2-17.8), 6.8 (5.4-22.4), and 11.7 (9.8-26.2) (ie, 2.7 [2.3-6.0] months to tolerance), respectively. One subject achieved partial success (negative inhibitor titer and IR ≥66%), and 5 subjects failed ITI, of which 2 had high inhibitors throughout, 2 experienced an increase in inhibitor levels, and 1 recorded a negative inhibitor titer at 282 days. Most bleeds occurred in the ITI period when median (IQR) ABRs (n=13) were 3.8 (0-10.1) overall, 0 (0-2.6) for spontaneous, 1 (0-4) for traumatic, and 0 (0-3.1) for joint. During tapering, median (IQR) ABRs (n=10) were overall, 0 (0-2.4); spontaneous, 0 (0-0); traumatic, 0 (0-1.3); and joint, 0 (0-0). All 16 subjects experienced ≥1 treatment-emergent AE (TEAE), the most frequent of which was pyrexia in 7 subjects (44%). One subject reported ≥1 related TEAE (injection site pain). Nine subjects (56%) experienced ≥1 treatment-emergent serious AE (TESAE). TESAEs occurring in ≥2 subjects included vascular device infection, contusion, and hemarthrosis. No treatment-related TESAEs, discontinuations due to AEs, or deaths were reported. Conclusions: rFVIIIFc is the first EHL FVIII with prospective data for first-time ITI in patients with severe hemophilia A with historical high-titer inhibitors. Evaluated within a 48-week timeframe, rFVIIIFc offered rapid time to tolerization (median 11.7 weeks; 2.7 months) with durable responses in almost two-thirds of subjects and was well tolerated. Optimizing ITI to eradicate inhibitors remains a priority. Figure 1 Figure 1. Disclosures Malec: CSL Behring: Consultancy; Genentech: Consultancy; HEMA Biologics: Consultancy; Pfizer: Consultancy; Sanofi: Consultancy, Research Funding; Takeda: Consultancy; Bioverativ: Consultancy, Research Funding, Speakers Bureau; Shire: Consultancy; Bayer: Consultancy. Van Damme: Pfizer: Consultancy; Shire: Consultancy; Bayer: Consultancy. Chan: Bioverativ: Consultancy. Jain: Sanofi: Ended employment in the past 24 months; Takeda: Current Employment, Current holder of stock options in a privately-held company. Sensinger: Sanofi: Current Employment, Current holder of stock options in a privately-held company. Dumont: Sanofi: Current Employment, Current holder of stock options in a privately-held company. Lethagen: Sobi: Current Employment, Current holder of stock options in a privately-held company. Carcao: Bayer, Bioverativ/Sanofi, CSL Behring, Novo Nordisk, Octapharma, Pfizer, Roche, and Shire/Takeda: Research Funding; Bayer, Bioverativ/Sanofi, CSL Behring, Grifols, LFB, Novo Nordisk, Pfizer, Roche, and Shire/Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees. Peyvandi: Roche: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Sobi: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Ablynx, Grifols, Kedrion, Novo Nordisk, Roche, Shire, and Sobi: Other: Personal Fees. OffLabel Disclosure: adheres to routine clinical practice

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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.

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A Subset of High Titer Acquired Hemophilia Patients May Benefit from Treatment with High Dose Factor VIII.

Blood ◽

10.1182/blood.v114.22.3476.3476 ◽

2009 ◽

Vol 114 (22) ◽

pp. 3476-3476

Author(s):

Shannon Meeks ◽

John F Healey ◽

Ernest T Parker ◽

Pete Lollar

Keyword(s):

Factor Viii ◽

Hemophilia A ◽

High Titer ◽

High Dose ◽

Type I ◽

C2 Domain ◽

Type Ii ◽

Acquired Hemophilia ◽

Proteolytic Activation

Abstract Abstract 3476 Poster Board III-413 Approximately 30% of patients with severe hemophilia A will develop inhibitory antibodies (Abs) to factor VIII (fVIII inhibitors). The immune response to fVIII currently is the most significant complication in the management of patients with hemophilia A. In addition, autoimmune Abs to fVIII can develop in non-hemophiliacs, producing acquired hemophilia A, which frequently produces life- or limb-threatening bleeding. Patients with autoimmune hemophilia often have Abs with type II kinetics in which there is incomplete inactivation of fVIII at saturating concentrations of inhibitor. We have characterized the antibody response to the C2 domain of human fVIII in a murine hemophilia model and described 5 structural groups of Abs. Groups A, AB, and B are classical anti-C2 Abs that block fVIII and fVIIIa binding to phospholipid. Groups BC and C consist of non-classical anti-C2 Abs that inhibit the proteolytic activation of fVIII but do not block the binding of fVIII to phospholipid. Subsequently, we identified classical and non-classical anti-C2 Abs in human fVIII inhibitor plasmas. Most murine non-classical Abs have inhibitor titers greater than 10,000 Bethesda units/mg IgG. In a murine in vivo bleeding model, both type I classical C2 Abs, type II non-classical C2 Abs, and a type I anti-A2 Ab produced similar amounts of blood loss that were significantly greater than control mice injected with 180 U/kg of fVIII alone. Increasing the dose of fVIII to 360 U/kg overcame the bleeding diathesis produced by the type II MAbs, but not the type I Abs. These results were consistent with the in vitro Bethesda assay in which a type I anti-A2 Ab, 4A4, completely inhibited both 1 U/mL and 3 U/mL fVIII, while there was 40% residual activity at saturating concentrations of a type II anti-C2 Ab, 2-77, at either concentration of fVIII. To determine if similar in vitro characteristics exist in patients with acquired hemophilia, plasmas from 3 patients with high titer type II inhibitors were studied. All 3 plasmas primarily had C2 domain epitope specificity that included non-classical Abs. Plasma A7 additionally had detectable anti-A2 activity. Recovery of fVIII activity after a 2 h incubation at 37 °C at nominal added concentrations of 1 mL and 3 U/mL fVIII was compared (Table 1). At 3 U/mL added fVIII, recovery of activity in plasmas A4 and A5 was 1.1 U/mL and 0.51 U/mL, respectively, despite the presence of inhibitor titers of 18 and 11 Bethesda units (BU) per mL. The presence of anti-A2 Abs, which typically have type I kinetics, may have contributed to the overall lower recovery of activity in plasma A7. These results suggest that treatment with high-dose fVIII rather than bypassing agents may be warranted in patients with an inhibitor response dominated by non-classical anti-C2 Abs. Table 1 Patient Plasma Inhibitor Titer (BU/mL) Recovered Activity at 1U/mL FVIII (U/mL) Recovered Activity at 3 U/mL FVIII (U/mL) A4 18 0.31 1.1 A5 11 0.18 0.51 A7 62 0.07 0.12 Disclosures: No relevant conflicts of interest to declare.

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Biological considerations of plasma-derived and recombinant factor VIII immunogenicity

Blood ◽

10.1182/blood-2016-11-750885 ◽

2017 ◽

Vol 129 (24) ◽

pp. 3147-3154 ◽

Cited By ~ 20

Author(s):

Jesse Lai ◽

Christine Hough ◽

Julie Tarrant ◽

David Lillicrap

Keyword(s):

Risk Factors ◽

Factor Viii ◽

Environmental Variables ◽

Neutralizing Antibodies ◽

Genetic Factors ◽

Hemophilia A ◽

Clinical Care ◽

Epidemiologic Studies ◽

Inhibitor Development ◽

Recombinant Fviii

Abstract In hemophilia A, the most severe complication of factor VIII (FVIII) replacement therapy involves the formation of FVIII neutralizing antibodies, also known as inhibitors, in 25% to 30% of patients. This adverse event is associated with a significant increase in morbidity and economic burden, thus highlighting the need to identify methods to limit FVIII immunogenicity. Inhibitor development is regulated by a complex balance of genetic factors, such as FVIII genotype, and environmental variables, such as coexistent inflammation. One of the hypothesized risk factors of inhibitor development is the source of the FVIII concentrate, which could be either recombinant or plasma derived. Differential immunogenicity of these concentrates has been documented in several recent epidemiologic studies, thus generating significant debate within the hemophilia treatment community. To date, these discussions have been unable to reach a consensus regarding how these outcomes might be integrated into enhancing clinical care. Moreover, the biological mechanistic explanations for the observed differences are poorly understood. In this article, we complement the existing epidemiologic investigations with an overview of the range of possible biochemical and immunologic mechanisms that may contribute to the different immune outcomes observed with plasma-derived and recombinant FVIII products.

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French Previously Untreated Patients with Severe Hemophilia A after Exposure to Recombinant Factor VIII : Incidence of Inhibitor and Evaluation of Immune Tolerance

Thrombosis and Haemostasis ◽

10.1055/s-0037-1615358 ◽

1998 ◽

Vol 80 (11) ◽

pp. 779-783 ◽

Cited By ~ 60

Author(s):

Y. Laurian ◽

E. P. Satre ◽

A. Borel Derlon ◽

H. Chambost ◽

P. Moreau ◽

...

Keyword(s):

Factor Viii ◽

Immune Tolerance ◽

Hemophilia A ◽

High Titer ◽

Recombinant Factor Viii ◽

High Dose ◽

Severe Hemophilia ◽

Inhibitor Development ◽

Intron 22 Inversion ◽

Median Period

SummaryFifty French previously untreated patients with severe hemophilia A (factor VIII <1%), treated with only one brand of recombinant factor VIII (rFVIII), were evaluated for inhibitor development, assessment of risk factors and outcome of immune tolerance regimen. The median period on study was 32 months (range 9-74) since the first injection of rFVIII. Fourteen patients (28%) developed an inhibitor, four of whom (8%) with a high titer (≥10 BU). All inhibitor patients but one continued to receive rFVIII either for on-demand treatment or for immune tolerance regimen (ITR). Among these patients, inhibitor was transient in 2 (4%), became undetectable in 6 and was still present in 6. The prevalence of inhibitor was 12%. Presence of intron 22 inversion was found to be a risk factor for inhibitor development. Immune tolerance was difficult to achieve in our series despite a follow-up period of 16 to 30 months: immune tolerance was complete in only one out of the 3 patients undergoing low dose ITR and in one out of the 5 patients with high dose ITR.

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Meta-Analysis on Incidence of Inhibitors in 1,945 Previously Untreated Patients Treated with Recombinant Factor VIII Products: Is There a Difference?

Blood ◽

10.1182/blood.v126.23.289.289 ◽

2015 ◽

Vol 126 (23) ◽

pp. 289-289 ◽

Cited By ~ 2

Author(s):

Lorenzo G. Mantovani ◽

Matteo Rota ◽

Paolo Cortesi ◽

Katharina Steinitz ◽

Armin Reininger ◽

...

Keyword(s):

Risk Factors ◽

Potential Risk ◽

Outcome Measure ◽

High Titer ◽

Meta Analysis ◽

Significant Heterogeneity ◽

Hazard Ratios ◽

Potential Risk Factors ◽

The Relationship ◽

Antihemophilic Factor

Abstract Introduction. Recent large cohort studies have shown data on inhibitor incidence in previously untreated patients (PUPs) with hemophilia A treated with recombinant factor VIII concentrates (rFVIII), which disputed previous reports or clinical trials. Aim of this meta-analysis was to assess the risk of inhibitor development in this patient population in order to clarify the relationship between the rFVIII product used and the development of FVIII inhibitors. Methods. We carried out a systematic literature search in electronic databases (Medline through PubMed, EMBASE) for studies published from 1 January 1988 to 31 January 2015. We aimed to identify clinical studies (both prospective and retrospective) investigating the relationship between rFVIII product used and the development of FVIII inhibitors in PUPs and minimally treated patients (MTPs), with less than 5 previous exposure days, with severe (FVIII<1%) and moderate (FVIII1-5%) hemophilia. We conducted the systematic review in accordance with the MOOSE (Meta-analysis of Observational Studies in Epidemiology) guidelines. The primary outcome measure of this meta-analysis was the development of clinically relevant inhibitory antibodies, while the secondary outcome measure was the development of a high-titer inhibitor, which was defined as a peak titer of at least 5 Bethesda units per millimeter (BU/mL) up to the 75th exposure day. We computed pooled meta-analytic estimates according to the rFVIII product used by using the inverse-variance method, assuming a fixed, or a random-effects model if significant between-studies heterogeneity was present. Heterogeneity was measured using Cochrane Q statistics and Higgins I-squared statistics, i.e. the ratio of true heterogeneity between studies compared to the total observed variation. Results. We identified 717 papers through database searches (538 from PubMed; 181 from EMBASE), of which 662 papers were excluded for the following reasons: duplicates (n=49); title and/or abstract not relevant for the endpoint of this study (n=231); review articles (n=131); letter to the editor (n=33); case-reports (n=98); animal studies (n=40); and others (n=80). Fifty-five (55) full-text papers were retrieved for detailed evaluation, plus eight additional papers identified through review of reference lists of the retrieved articles. Of these, 47 articles were excluded after full-text evaluation (incompleteness of data, multiple publications on the same cohort); sixteen (16) studies were included in the final meta-analysis. The pooled estimate of all inhibitors (571 inhibitors out of 1,945 PUPs/MTPs), including high titer (>5 BU/mL) and low titer (≤ 5 BU/mL), in the overall population considered was 0.27 (95% CI: 0.23-0.31) with significant heterogeneity (I-squared: 68.9%, p<0.01). Considering only inhibitors in PUPs with severe hemophilia (353 inhibitors out of 1,223 PUPs), the pooled estimate of all inhibitors was 0.27 (95% CI: 0.23-0.32) with significant heterogeneity (I-squared: 64.9%, p<0.01). The heterogeneity observed was due to differences of inhibitor incidence among studies for the same product used. Pooled inhibitor incidence estimates among products used ranged from 0.23 to 0.42 with overlapping confidence intervals, in the absence of heterogeneity (p=0.28). Similar patterns were observed in subpopulations of patients with high titer inhibitors or low titer inhibitors. Only few studies reported inhibitor hazard ratios with the different products used, adjusted to slightly different potential risk factors (Gouw et al, 2007, Gouw et al, 2013, Calvez et al, 2014, Collins et al, 2014). Meta-analysis of these studies showed PUPs/MTPs treated with Antihemophilic Factor (Recombinant) (Advate, Baxalta US Inc., Westlake Village, CA 91362) had a pooled inhibitor hazard ratio estimate of 0.63 (95% CI 0.48-0.83) as compared to Antihemophilic Factor (Recombinant) (Kogenate FS, Bayer HealthCare LLC, Whippany, NJ 07981). The pool estimates of other products used and tested were not significantly different. Conclusions. The incidence of inhibitors in PUPs/MTPs included in this meta-analysis was 27%. Although significant heterogeneity among studies was observed, no significant differences among products were found. Differences between products used were found only by considering hazard ratios in which potential risk factors were considered. Disclosures Mantovani: Baxalta Innovation GmbH: Consultancy. Rota:Baxalta Innovations GmbH: Consultancy. Cortesi:Baxalta Innovations GmbH: Consultancy. Steinitz:Baxalta Innovations GmbH: Employment. Reininger:Baxalta Innovations GmbH: Employment. Gringeri:Baxalta Innovations GmbH: Employment.

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Risk Factors for the Development of High-Titer Inhibitors in 260 Children with Severe Hemophilia a Born Between 1990 and 2009: The Remain Study

Blood ◽

10.1182/blood.v128.22.3774.3774 ◽

2016 ◽

Vol 128 (22) ◽

pp. 3774-3774

Author(s):

Maria Elisa Mancuso ◽

Kathelijn Fischer ◽

Elena Santagostino ◽

Johannes Oldenburg ◽

Helen Platokouki ◽

...

Keyword(s):

Family History ◽

Board Of Directors ◽

Research Funding ◽

Hemophilia A ◽

High Titer ◽

High Dose ◽

Severe Hemophilia ◽

Advisory Committees ◽

History Of

Abstract The development of anti-FVIII antibodies (i.e., inhibitors) is the major side effect of severe hemophilia A treatment. Inhibitors mainly develop in children during the first 50 exposure days and are classified in low-and high-titer (i.e., peak titer < or > 5 UB/ml). High-titer inhibitors have the major clinical impact. At diagnosis however, the real nature of the antibody is not clear in all patients, since some low-titer inhibitors may progress to high-titer. The determinants of the evolution from low- to high-titer inhibitors are still unclear and the aim of the present study was to investigate potential risk factors associated with the progression from low- to high-titer inhibitors. This study is a follow-up study of the PedNet Registry and includes 260 children with severe hemophilia A and clinically relevant inhibitors, born between 1990 and 2009 and consecutively recruited from 31 hemophilia centers in 16 countries. Clinical and laboratory data were collected from the date of first positive inhibitor test and covered a minimum of 3-years follow-up. Factors potentially associated with progression from low- to high-titer inhibitor development were analyzed using univariate and multivariate logistic regression. F8 mutation type was known in 247 patients (95%), including 202 (82%) null mutations (i.e., large deletions, nonsense mutations and inversions). Positive family history of inhibitors was present in 37 of 99 (37%) with positive family history of hemophilia. At diagnosis 49% (n=127) had low-titer inhibitors, however, upon FVIII re-exposure, 50% of low-titer inhibitors progressed to high-titer and only 25% of patients (n=69) had persistent low-titer inhibitors. Within the first 3 years of follow-up, immune tolerance induction (ITI) was equally implemented in around 80% of low-and high-titer patients but it was started later in children with high-titers (median time to ITI start 4.5 vs 0.3 months; p<0.001) in whom daily regimens and high-dose FVIII were more frequently adopted (89, 67% vs 41, 50% and 98, 74% vs 35, 43%; p=0.01 and <0.001, respectively). Overall high-titer inhibitor development was associated with null F8 mutations (OR 2.8, 95%CI 1.4-5.5) and family history of inhibitors (OR 3.9, 95%CI 1.2-12.6). The progression from low- to high-titer inhibitors during follow up, was associated with the use of high-dose ITI regimens (i.e., >100 IU/kg/day) with an OR of 3.9 (95%CI 1.5-10.0), independent from the effects of F8 mutation type (adjusted OR 3.6, 95%CI 1.4-9.8) and family history of inhibitors (adjusted OR 6.7, 95%CI 1.1-42.6). No difference was found by comparing the use of daily versus non-daily ITI. In conclusion, in a cohort of 260 children with severe hemophilia A and inhibitors, 49% presented with low-titers at diagnosis and 46% of them progressed to high-titers during follow-up. Progression to high-titer inhibitors was associated with the use of high-dose ITI. These results suggest that intensive ITI should be avoided as initial strategy in low-titer inhibitor patients. Disclosures Mancuso: Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sobi/Biogen Idec: Consultancy, Speakers Bureau; Novo Nordisk: Consultancy, Speakers Bureau; CSL Behring: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Baxalta: Consultancy, Speakers Bureau; Bayer Healthcare: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kedrion: Consultancy. Fischer:Wyeth/Pfizer: Research Funding; Biogen: Consultancy; NovoNordisk: Consultancy, Research Funding, Speakers Bureau; Pfizer: Consultancy, Speakers Bureau; Biotest Octapharma: Speakers Bureau; CSL Behring: Speakers Bureau; Baxter: Consultancy, Research Funding, Speakers Bureau; Freeline: Consultancy; Bayer: Consultancy, Research Funding, Speakers Bureau. Santagostino:Octapharma: Consultancy; Novo Nordisk: Consultancy; Kedrion: Consultancy; Sobi: Consultancy; Biogen Idec: Consultancy; Roche: Consultancy; Grifols: Consultancy; Pfizer: Consultancy; Baxalta: Consultancy; CSL Behring: Consultancy; Bayer: Consultancy. Escuriola:Baxalta, now part of Shire: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Investigator Clinical Studies, Research Funding; Bayer: Consultancy, Honoraria, Research Funding; Biotest: Consultancy, Honoraria, Research Funding; CSL Behring: Consultancy, Honoraria, Research Funding; Grifols: Consultancy, Honoraria, Research Funding; Octapharma: Consultancy, Honoraria, Research Funding; NovoNordisk: Consultancy, Honoraria, Research Funding. Liesner:BPL: Consultancy, Honoraria, Research Funding; Bayer: Consultancy, Honoraria, Speakers Bureau; Cangene: Research Funding; CSL Behring: Consultancy, Honoraria, Research Funding; Baxalta Innovations GmbH, now a part of Shire: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; SOBI: Consultancy, Honoraria, Research Funding, Speakers Bureau; Octapharma: Consultancy, Honoraria, Research Funding, Speakers Bureau; Biogen: Consultancy, Honoraria, Research Funding; Grifols: Consultancy, Honoraria. Nolan:Sobi: Research Funding; Biogen: Research Funding.

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What is the role of an extended half-life product in immune tolerance induction in a patient with severe hemophilia A and high-titer inhibitors?

Hematology ◽

10.1182/asheducation-2016.1.648 ◽

2016 ◽

Vol 2016 (1) ◽

pp. 648-649 ◽

Cited By ~ 1

Author(s):

Maissaa Janbain ◽

Steven Pipe

Keyword(s):

Immune Tolerance ◽

Half Life ◽

Hemophilia A ◽

High Titer ◽

Tolerance Induction ◽

High Dose ◽

Severe Hemophilia ◽

Immune Tolerance Induction ◽

History Of

Abstract A 10-year-old boy presents with a history of severe hemophilia A and high-titer inhibitor that had failed high-dose immune tolerance induction (ITI) with a recombinant factor VIII (rFVIII) product and a plasma-derived FVIII product. You are asked by his mother whether he should be tried on ITI with an extended half-life product, in particular, consideration of a rFVIIIFc concentrate.

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Efficacy and safety of simoctocog alfa (Nuwiq®) in patients with severe hemophilia A: a review of clinical trial data from the GENA program

Therapeutic Advances in Hematology ◽

10.1177/2040620719858471 ◽

2019 ◽

Vol 10 ◽

pp. 204062071985847 ◽

Cited By ~ 2

Author(s):

Toshko Lissitchkov ◽

Anna Klukowska ◽

John Pasi ◽

Craig M. Kessler ◽

Robert Klamroth ◽

...

Keyword(s):

Hemophilia A ◽

High Titer ◽

Clinical Trial Data ◽

Severe Hemophilia ◽

Efficacy And Safety ◽

Previously Treated Patients ◽

Previously Treated ◽

Recombinant Fviii ◽

Actual Incidence ◽

Human Specific

Simoctocog alfa (human-cl rhFVIII, Nuwiq®) is a 4th generation recombinant FVIII (rFVIII), without chemical modification or fusion with any other protein/fragment. Nuwiq® is produced in a human embryonic kidney cell line (HEK293F), which ensures human-specific post-translational protein processing. Nuwiq® was evaluated in seven prospective clinical studies in 201 adult and pediatric previously treated patients (PTPs) with severe hemophilia A. The NuProtect study in 110 previously untreated patients (PUPs) is ongoing. The mean half-life of Nuwiq® was 15.1–17.1 h in PTP studies with adults and adolescents, and 12.5 h in children aged 2–12 years. Clinical trials in PTPs demonstrated the efficacy and safety of Nuwiq® in the prevention and treatment of bleeds and as surgical prophylaxis. In the NuPreviq study of pharmacokinetic (PK)-guided personalized prophylaxis in 66 adult PTPs, 83% of patients had no spontaneous bleeds during 6 months of personalized prophylaxis and 57% were treated ⩽2 per week. No FVIII inhibitors were detected in PTPs after treatment with 43,267 injections and >80 million IU of Nuwiq®. Interim data for 66 PUPs with ⩾20 exposure days to Nuwiq® in NuProtect demonstrated a low cumulative high-titer inhibitor rate of 12.8% [actual incidence 12.1% (8/66)] and convincing efficacy and safety.

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