Immune Tolerance Induction Using Rfviiifc (Eloctate)

Abstract Introduction: Inhibitor formation affects approximately 30% of individuals with severe hemophilia A. The eradication of inhibitors using immune tolerance induction (ITI) remains the mainstay of therapy, although typically requires daily high-dose factor VIII via a port for up to a year. Extended half-life recombinant factor VIII Fc fusion protein (rFVIIIFc, Eloctate¨) has a half-life extension 1.5-fold longer than standard recombinant FVIII (rFVIII), reducing treatment frequency, and also induces regulatory T cell response to FVIII in animal models. We hypothesized that rFVIIIFc would provide more effective ITI, specifically shortening ITI, than rFVIII. We describe ITI with rFVIIIFc in three patients with severe hemophilia A. Methods: Immune tolerance induction was initiated with rFVIIIFc (Eloctate) in three children with severe hemophilia A and an anti-FVIII inhibitor. Dosing was per MD discretion with family agreement, and performed by central venous access device or intravenous infusion via heplock. Follow-up was scheduled every 6-8 weeks, with planned determination of FVIII half-life once the anti-FVIII fell to <0.6 B.U. Tolerance was a priori defined as achieving anti-FVIII <0.6 B.U. and half-life, t½ >6 hours. FVIII half-life was determined by one-stage FVIII:C assay on citrate samples drawn pre- and 10 minutes, 1, 2, 4, and 6 hours post-infusion of a single dose of rFVIIIFc. Once a t½ >6 hours was documented, incremental reduction to 50 IU/kg every other day or three times weekly, once there was evidence of maintenance of inhibitor neutralization and a >6 hour FVIII:C half-life. Results: Immune tolerance induction was initiated with rFVIIIFc at a dose of 100-200 IU/kg rFVIIIFc via central venous access device every other day or three times weekly per MD discretion in three children with severe hemophilia A and in anti-FVIII inhibitor > 5 B.U. (Table 1). Two patients had F8 genetic testing. In two patients, Pt 1 and Pt 3, this was the initial ITI course, and in the third child (Pt 2) this was salvage ITI after failing to achieve tolerance due to noncompliance with daily rFVIII ITI taper regimen. In two rFVIIIFc ITI was begun when anti-FVIII was < 10 B.U. Historic peak titers were 16-422 B.U. The time to anti-FVIII tolerance was 4-12 weeks Discussion: Immune tolerance induction was successful in three children with inhibitors using rFVIIIFc, including a child previously failing rFVIII ITI. The time to anti-FVIII=0 was 4-12 weeks, significantly shorter than with current rFVIII ITI. There were no adverse effects. These data indicate that rFVIIIFc safely and effectively induced immune tolerance to FVIII in children with inhibitors. Whether ITI may be accomplished more rapidly with rFVIIIFc, and the optimal dose for ITI will require prospective studies. A prospective observational study of rFVIIIFc ITI pre- and post-ITI T cell responses in children with hemophilia and inhibitors, the H emophilia I nhibitor R esponse to E loctate (HIRE) Study, is underway. Table 1. Immune Tolerance Induction with rFVIIIFc in Hemophilia A Inhibitor Patients Patient (Pt) Hemophilia Severity F8 Gene Mutation Age at Anti-FVIII Detection Peak Anti-FVIII Titer Initial ITI Dose Time toAnti-FVIII = 0 Current Anti-FVIII 1 <0.01 IU/ml Intron 22 inversion 13 months 32 B.U. 200 IU/kg QOD 12 weeks 0 B.U. 2 < 0.01 IU/ml Exon 18 nonsense variant 9 months 422 B.U. 200 IU/kg 3x/week 4 weeks 0 B.U. 3 <0.01 IU/ml Not available 10 years 16 B.U. 100 IU/kg QOD 11 weeks 0 B.U. Disclosures Malec: Baxter: Research Funding; Biogen: Research Funding. Ragni:Pfizer: Research Funding; Tacere Benitec: Membership on an entity's Board of Directors or advisory committees; Baxalta: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol Myers Squibb: Research Funding; Dimension: Research Funding; Vascular Medicine Institute: Research Funding; Shire: Membership on an entity's Board of Directors or advisory committees, Research Funding; CSL Behring: Research Funding; SPARK: Research Funding; Biomarin: Research Funding; Genentech Roche: Research Funding; Bayer: Research Funding; Biogen: Research Funding; Alnylam: Research Funding. Journeycake:CSL, Baxalta, NovoNordisk: Consultancy; ATHN: Research Funding; Biogen: Speakers Bureau; ATHN: Membership on an entity's Board of Directors or advisory committees.

Download Full-text

Natural History Of Inhibitor Recurrence Following Successful Immune Tolerance Induction

Blood ◽

10.1182/blood.v122.21.1106.1106 ◽

2013 ◽

Vol 122 (21) ◽

pp. 1106-1106 ◽

Cited By ~ 2

Author(s):

Ana G. Antun ◽

Paul Monahan ◽

Marilyn J. Manco-Johnson ◽

Michael Callaghan ◽

Guy Young ◽

...

Keyword(s):

Board Of Directors ◽

Immune Tolerance ◽

Half Life ◽

Research Funding ◽

Tolerance Induction ◽

Advisory Committees ◽

Immune Tolerance Induction ◽

Baxter Healthcare ◽

Inhibitor Titer

Abstract Introduction The formation of Factor VIII (FVIII) inhibitory antibodies is a major complication of hemophilia A. Currently immune tolerance induction (ITI) is successful in up to 70% of patients. Outside of the International Immune Tolerance Registry, where 6 of 128 patients had a recurrent inhibitor between 1 and 6 years, little is known about the probability of inhibitor recurrence following successful ITI. Objective To determine the probability of inhibitor recurrence and the influence of adherence to post-ITI prophylaxis on inhibitor recurrence following successful ITI. Methods All persons with hemophilia A (FVIII level < 50%) who completed ITI (defined as inhibitor titer <0.6 BU/ml) between 1/1/1998 and 8/15/2010 at 12 U.S. Hemophilia Treatment Centers were identified. Demographic and clinical characteristics were obtained through review of subject medical records and included age at start of ITI, race, ethnicity, hemophilia severity, peak inhibitor titer prior to the start of ITI and ITI regimen. For those subjects where tolerance was confirmed with measurement of FVIII half-life > 6 hours and/or FVIII recovery > 66% in addition to inhibitor titer < 0.6 BU/ml, information was also collected on post-ITI prophylaxis regimen, adherence to post-ITI prophylaxis, and the presence of a recurrent inhibitor titer (≥ 0.6 BU/ml) or last inhibitor titer prior to 8/15/2011. Adherence during the 6 months prior to inhibitor recurrence or last inhibitor titer was determined by review of pharmacy and infusion logs compared with prescribed treatment regimen. Follow-up time started when the subject was considered tolerized (normalized half-life or recovery if half-life not performed) and ended at the time of inhibitor recurrence or the last recorded inhibitor titer. Estimates of the probability of remaining inhibitor-free at 1, 3 and 5 years were calculated with the Kaplan-Meier method. The association between adherence (completing >80% of prescribed infusions vs. < 80% of prescribed infusions) and inhibitor recurrence was assessed using the chi-square test. Results Eighty-three male subjects were enrolled. The median age at start of ITI was 3.3 years (range: 0.08 - 39). The majority of the subjects were white (73%) and non-Hispanic (73.5%). Seventy-one (85.6%) had severe hemophilia. The median peak inhibitor titer was 8.5 BU/ml (range: 0.6 - 950). Four subjects (5%) had a prior unsuccessful course of ITI. FVIII alone was used in 85% of subjects. Sixty-seven (80.7%) met criteria for tolerance and 64 had follow-up data available, with a median follow up time of 3.4 years (range: 0.08-12.4). Forty-four subjects (68.7%) remained tolerant without a recurrent inhibitor titer after a median 4.7 years (range: 0.25-12.4) of follow-up. Twenty subjects (31.3%) had at least one inhibitor titer ≥ 0.6 BU/ml after a median of 1.6 years (range 0.08-5.7). The probability of recurrent inhibitor at 1 year is 0.15 (95% CI: [0.05, 0.20]); at 3 years is 0.30 (95% CI: [0.2, 0.4]) and 5 years is 0.35 (95% CI: [0.2, 0.5]) (Figure 1). Four subjects discontinued post-ITI prophylaxis anywhere from 6 months to greater than 6 years after tolerance was achieved, of whom 2 (50%) developed a recurrent inhibitor. Of those that remained on post-ITI prophylaxis, 41 subjects (64.1%) were adherent (took >80% of prescribed infusions) to their post-ITI prophylaxis regimen, of whom 13 (31.7%) developed a recurrent inhibitor. Twenty-three (35.9%) who were non-adherent (took <80% of the prescribed infusions) of which 7 (30.4%) subjects developed a recurrent inhibitor; no statistically significant association was found between adherence and inhibitor-free status (p=0.92). Conclusion ITI is currently the most effective treatment to eradicate FVIII inhibitors, however 5 years after completion, 30-35% of patients will have at least one inhibitor titer ≥ 0.6 BU/ml. A recurrent inhibitor is unlikely after 5 years. Adherence to post-ITI prophylaxis does not appear to be a major driver of inhibitor recurrence. It is imperative to elucidate the factors that influence the durability of successful ITI to improve quality of life and cost of treatment in these patients. Disclosures: Monahan: Baxter: Consultancy, Honoraria, Research Funding, travel support, travel support Other; Bayer: Honoraria, Membership on an entity’s Board of Directors or advisory committees; Novo Nordisk: Consultancy, Honoraria, Research Funding; Pfizer: Honoraria; Prolor Biotech: Research Funding; Asklepios: Consultancy, Research Funding, travel support Other. Manco-Johnson:Eisai: Research Funding; Novo Nordisk: Membership on an entity’s Board of Directors or advisory committees; Biogen Idec: Membership on an entity’s Board of Directors or advisory committees; Baxter BioScience: Membership on an entity’s Board of Directors or advisory committees; CSL Behring: Membership on an entity’s Board of Directors or advisory committees, Research Funding; Bayer HealthCare: Membership on an entity’s Board of Directors or advisory committees, Research Funding. Carpenter:Novo Nordisk: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding; CSL Behring: Honoraria, Research Funding; Grifols: Honoraria, Research Funding. Kruse-Jarres:Bayer HealthCare: Consultancy; Biogen IDEC: Consultancy; Grifols: Consultancy; Kedrion: Consultancy; Novo Nordisk: Consultancy; Baxter Healthcare: Consultancy. Ragni:Novo Nordisk: Research Funding; Merck: Research Funding; CSL Behring: Research Funding; Bayer: Research Funding; Baxter: Research Funding; Tacere Benitec: Consultancy; Smith Kline Glaxo: Consultancy, Research Funding; Bristol Myers Squibb: Consultancy, Research Funding; Biogen Idec: Membership on an entity’s Board of Directors or advisory committees, Research Funding; Pfizer: Research Funding. Kempton:Novo Nordisk: Research Funding; Baxter Healthcare: Membership on an entity’s Board of Directors or advisory committees.

Download Full-text

Durability of ITI Utilizing Rfviiifc

Blood ◽

10.1182/blood.v128.22.3793.3793 ◽

2016 ◽

Vol 128 (22) ◽

pp. 3793-3793

Author(s):

Margaret V. Ragni ◽

Lynn M. Malec ◽

Janna M. Journeycake

Keyword(s):

Immune Tolerance ◽

Half Life ◽

Research Funding ◽

Hemophilia A ◽

Tolerance Induction ◽

Severe Hemophilia ◽

Immune Tolerance Induction ◽

Viii Inhibitor ◽

Inhibitor Titer

Introduction: The eradication of inhibitors using immune tolerance induction (ITI) remains the mainstay of therapy in patients with severe hemophilia A who develop inhibitors. The long-acting recombinant factor VIII Fc fusion protein, rFVIIIFc (Eloctate™), which is safe and effective in the prevention and treatment of bleeding events, may promote tolerance to FVIII as shown in preclinical animal models and an inhibitor prone child, as Fc suppresses immunoregulatory Tcells to proteins to which Fc is attached. We therefore previously hypothesized rFVIIIFc would provide effective ITI, specifically shortening and simplifying ITI, and have previously described successful inhibitor eradication in three patients. Long-term follow-up data after successful ITI in patients with severe hemophilia remains limited. In the International Immune Tolerance Induction study, at 1-year follow-up, 6 of 66 subjects who had achieved tolerance demonstrated evidence of relapse at a median of 9.5 months. Of these 6 subjects, 1 had a measurable inhibitor titer and 5 had reduced FVIII recovery. We aim to provide follow-up data on our cohort of patients who had successful inhibitor eradication utilizing rFVIIIFc for ITI. Methods: Immune tolerance induction was initiated in three patients with severe hemophilia A and anti-VIII >5 B.U., in two as initial ITI (Pt. 1, 3), and one as salvage (Pt. 2) after failing to achieve ITI with standard rFVIII due to poor compliance. Follow-up was scheduled every 6-8 weeks, with planned determination of FVIII half-life once the anti-FVIII fell to <0.6 B.U. Tolerance was a priori defined as achieving anti-FVIII <0.6 B.U., FVIII recovery of at least 60%, and half-life (t½) >6 hours. Once a t½ >6 hours was documented, incremental reduction to rFVIIIFc occurred. Patients continued to be followed by their local HTC as per standard of care. Results: ITI was initiated with rFVIIIFc at a dose of 100-200 IU/kg rFVIIIFc every other day or three times weekly per MD discretion. The time to initial anti-FVIII <0.6 B.U. was 4-12 weeks. Patient 1 and 2 were able to achieve tolerance, with a FVIII recovery of at least 60%, and half-life (t½) >6 hours, at weeks 18 and 17, respectively, after initiation of ITI. Patient 3 has improved but is not yet fully tolerized, as evidenced by 57% recovery and a t½ of approximately 7 hours. Anti-VIII inhibitor titers remain negative at 15, 16 and 15 months, from the initiation of ITI in patients 1, 2, and 3 respectively. Patients 1 and 2 have been able to decrease their post ITI prophylaxis dosing regimen to 80 IU/kg and 65 IU/kg three times a week while maintaining a FVIII trough of >1%. No patients were maintained on bypassing prophylaxis during ITI and no patients have experienced hemarthroses or other major bleeding event since the initiation of ITI. Discussion: Immune tolerance induction was successful in three children with inhibitors using rFVIIIFc, including a child previously failing rFVIII ITI. The time to anti-FVIII=0 was 4-12 weeks, significantly shorter than with current rFVIII ITI. At a mean duration of follow up of 15.3 months, all patients achieved an anti-VIII inhibitor titer of 0 B.U. Repeat pharmacokinetics studies will be available at planned subsequent follow-up visit. To date, these data indicate that rFVIIIFc safely and effectively induced immune tolerance to FVIII in three children with inhibitors, and has provided durable and continuing immune tolerance to FVIII. Whether rFVIIIFc ITI will be successful and durable in a larger cohort of children with severe hemophilia A will require prospective studies. A prospective observational study of rFVIIIFc ITI pre- and post-ITI T cell responses in children with hemophilia and inhibitors, the Hemophilia Inhibitor Response to Eloctate (HIRE) Study, has begun recruitment. Disclosures Ragni: SPARK: Research Funding; Shire: Consultancy; Novo Nordisk: Research Funding; Genentech: Research Funding; CSL Behring: Research Funding; Biomarin: Consultancy; Biogen: Consultancy, Research Funding; Baxalta: Research Funding; Alnylam Pharmaceuticals: Consultancy, Research Funding; Tacere Benitec: Consultancy; Vascular Medicine Institute: Research Funding; OPKO: Research Funding. Malec:Vascular Medicine Institute: Research Funding; Biogen: Research Funding; Baxalta: Research Funding; Biogen: Consultancy. Journeycake:CSL: Consultancy; Biogen: Consultancy; Baxalta/Shire: Consultancy.

Download Full-text

Target Joint Bleeding in Pediatric Patients with Hemophilia Α Receiving Twice Weekly Prophylaxis with a Pegylated Full-Length Recombinant Factor VIII with Extended Half-Life

Blood ◽

10.1182/blood.v128.22.3778.3778 ◽

2016 ◽

Vol 128 (22) ◽

pp. 3778-3778

Author(s):

Amy L. Dunn ◽

Alexis A. Thompson ◽

Werner Engl ◽

Marlies Sharkhawy ◽

Brigitt E. Abbuehl

Keyword(s):

Factor Viii ◽

Board Of Directors ◽

Half Life ◽

Research Funding ◽

Pediatric Patients ◽

Hemophilia A ◽

Point Estimate ◽

Severe Hemophilia ◽

Advisory Committees ◽

The Mean

Abstract Introduction: Patients with hemophilia A are at risk for acute bleeding which may affect muscles and other soft tissues but characteristically involves joints. Prophylaxis with factor VIII (FVIII) is the optimal treatment to prevent bleeding into joints and, when begun at a young age, may prevent arthropathy. BAX 8551, a polyethylene glycol (peg)ylated, full-length, recombinant FVIII built on ADVATE2, demonstrated extended half-life, efficacy, and safety for prophylaxis and treatment of bleeding in patients with severe hemophilia A. Methods: A phase 3, prospective, uncontrolled, multicenter study was performed in pediatric patients with severe hemophilia A without history of inhibitors. To be eligible, patients aged <6 years had to have ≥50, those aged 6 to <12 years ≥150 previous exposure days (EDs) to FVIII. Patients received twice weekly infusions of 50 ±10 IU/kg of BAX 855 over a period of 6 months or ≥50 EDs. The prevalence of target joints, defined as a single joint with ≥3 spontaneous bleeding episodes in any consecutive 6-month period, was assessed at baseline. Annualized rates of target joint bleeds and the course of target joints were evaluated by age (<6 and 6 to <12 years). The study was performed in accordance with the principles of the Declaration of Helsinki of the World Medical Association. Results:Sixty-six patients were treated with a mean (SD) BAX 855 dose of 51.1 (5.5) IU/kg at a mean (SD) frequency of 1.8 (0.2) infusions/week. Fourteen of 66 patients (21.2%), 3/32 (9.4%) in the younger and 11/34 (32.4%) in the older cohort, had a total of 23 target joints at screening. The number of target joint bleeds decreased during a mean (SD) of 48.5 (7.7; median: 49.0) prophylactic EDs/patient. Five of 66 (7.6%) patients had at least 1 target joint bleed, 1/32 (3.1%) in the younger and 4/34 (11.8%) in the older cohort. The point estimate for the mean (95% CI) annualized rate of target joint bleeds was 0 (0 - infinity; median: 0) compared to an annualized rate of all joint bleeds of 1.1 (0.6 - 1.9; median: 0) and an annualized rate of all bleeds of 3.0 (2.2 - 4.2; median: 2.0) (Table 1). The point estimate for the mean (95% CI) annualized bleeding rate (ABR) in 52 patients without target joints was 2.9 (2.0 - 4.2; median: 2.0) and was similar in 14 patients with target joints at screening at 3.5 (1.9 - 6.6; median: 2.1). In the younger cohort, the ABR was lower in patients with than those without target joints. However, the number of patients <6 years with target joints (N = 3) was too small to draw any conclusions (Table 1). During BAX 855 prophylaxis, no new target joints developed in any patient. Ten of 14 patients had at least 1 target joint revert to a non-target joint. In 8 of these 10 patients, 4 with 1 and 4 with 2 target joints, all target joints resolved. Conclusions:These results suggest that twice weekly infusion of BAX 855 is effective in the prevention of bleeding into target joints and may revert target to non-target joints in pediatric patients with severe hemophilia A. 1BAX 855 (Baxalta US Inc., now part of Shire) is licensed in the US and Japan under the trade name ADYNOVATE. 2ADVATE is a trade mark of Baxalta US Inc., now part of Shire. Disclosures Dunn: NovoNordisk: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Kedrion: Research Funding; Pfizer: Research Funding; CSL Behring: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Biogen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Baxalta (now part of Shire): Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Octapharma: Research Funding. Thompson:Eli Lily: Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Research Funding; bluebird bio: Consultancy, Research Funding; ApoPharma: Consultancy, Membership on an entity's Board of Directors or advisory committees; Mast: Research Funding; Amgen: Research Funding; Baxalta (now part of Shire): Research Funding. Engl:Shire: Employment, Equity Ownership. Sharkhawy:Baxalta (now part of Shire): Employment. Abbuehl:Baxalta (now part of Shire): Employment.

Download Full-text

BIVV001: The First Investigational Factor VIII Therapy to Break Through the VWF Ceiling in Hemophilia A, with Potential for Extended Protection for One Week or Longer

Blood ◽

10.1182/blood-2018-99-113575 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 636-636 ◽

Cited By ~ 7

Author(s):

Barbara A Konkle ◽

Amy Shapiro ◽

Doris Quon ◽

Janice Staber ◽

Takashi Suzuki ◽

...

Keyword(s):

Single Dose ◽

Board Of Directors ◽

Half Life ◽

Research Funding ◽

Low Dose ◽

Hemophilia A ◽

High Dose ◽

Severe Hemophilia ◽

Advisory Committees ◽

Dose Cohort

Abstract Introduction: The standard of care for patients with severe hemophilia A is prophylactic factor VIII (FVIII) replacement. Conventional recombinant FVIII products are efficacious but require frequent administration because of their short half-life, which reflects the dependence of FVIII on von Willebrand factor (VWF). Recombinant FVIII Fc fusion protein (rFVIIIFc) provides an extended dosing interval, as well as joint protection and improved quality of life (Oldenburg et al, Haemophilia, 2018; Wang et al, Blood, 2016), with a well-characterized safety profile. While rFVIIIFc reduces the required administration frequency, longer prophylactic dosing intervals that also offer maximum overall protection are still an unmet need for patients with severe hemophilia A. Increasing the half-life of rFVIII is ultimately dependent upon decoupling FVIII and endogenous VWF. BIVV001 (rFVIII-VWF-XTEN) is a novel investigational rFVIII therapy with single-chain FVIII, the Fc domain of human immunoglobulin G1, 2 XTEN polypeptides, and the FVIII-binding D′D3 domain of VWF, designed to circulate in plasma independently of VWF, thereby breaking the VWF half-life ceiling. Here, we present the low-dose cohort results of EXTEN-A, a Phase 1/2a study assessing the safety and tolerability of a single dose of BIVV001, and the pharmacokinetic (PK) characteristics of a single dose of BIVV001 compared with rFVIII. Methods: EXTEN-A (NCT03205163) is an open-label, dose-escalation, multicenter study. Previously treated adult males with severe hemophilia A (<1 IU/dL [<1%] endogenous FVIII activity) with ≥150 exposure days to FVIII products were included. Patients were assigned to either the low-dose cohort (25 IU/kg of rFVIII and 25 IU/kg of BIVV001; n≥6) or the high-dose cohort (65 IU/kg of rFVIII and 65 IU/kg of BIVV001; n≥8). Escalation from the low-dose cohort, and enrolment of patients to the high-dose cohort was undertaken after assessment of available data from the low-dose cohort. After a screening and washout period of up to 28 days, patients received a single dose (25 or 65 IU/kg) of rFVIII. After a 3- to 4-day washout period, patients received a single dose of BIVV001 at the same dose level as rFVIII. Blood samples for PK analysis were collected for 3 days after dosing of rFVIII and up to 14 days after dosing of BIVV001. Inhibitor testing was performed 14 and 28 days following BIVV001 administration. Adverse events, clinical abnormalities in laboratory tests (including inhibitor development), and PK parameters were assessed. An interim analysis is planned, including the first 2 patients of the high-dose cohort. Results: Out of 7 patients enrolled in the low-dose cohort (25 IU/kg), 6 patients were dosed with BIVV001. Patients in this group were primarily white, with 1 patient of Asian descent, and 1 of Hispanic/Latino ethnicity. Patient ages ranged from 19 to 60 years. Low-dose BIVV001 was well tolerated and no inhibitors were detected through 28 days after BIVV001 dosing. Low-dose BIVV001 demonstrated an extended half-life of 37.6 hours, compared with a 12.1-hour half-life for rFVIII. Average FVIII activity post-infusion of BIVV001 was 12.2% at 5 days and 5.3% at 7 days. At least 8 patients will be enrolled in the high-dose cohort (65 IU/kg); preliminary data for the first 2 patients will be reported. Conclusions: BIVV001 was well tolerated in 6 patients with severe hemophilia A who were treated with a single low dose (25 IU/kg). No patient developed an inhibitor to FVIII. Low-dose cohort data demonstrated a breakthrough in the half-life of rFVIII therapy, with BIVV001 providing sustained FVIII levels that could potentially allow for more optimal, extended protection for patients. Disclosures Konkle: Genentech: Consultancy; Spark: Consultancy, Research Funding; Pfizer: Research Funding; Gilead: Consultancy; CSL Behring: Consultancy; Bioverativ: Research Funding; BioMarin: Consultancy; Sangamo: Research Funding; Shire: Research Funding. Shapiro:Shire: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; BioMarin: Research Funding; Prometic Life Sciences: Consultancy, Research Funding; Bioverativ, a Sanofi Company: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sangamo Biosciences: Consultancy; Genetech: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Bayer Healthcare: Other: International Network of Pediatric Hemophilia; OPKO: Research Funding; Octapharma: Research Funding; Kedrion Biopharma: Consultancy, Research Funding; Bio Products Laboratory: Consultancy; Daiichi Sankyo: Research Funding; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees, Research Funding. Quon:Bioverativ, a Sanofi Company: Speakers Bureau; Octapharma: Consultancy; Genetech: Consultancy, Speakers Bureau; Bayer: Consultancy; NovoNordisk: Consultancy, Speakers Bureau; Shire: Speakers Bureau. Staber:uniQure: Honoraria; NovoNordisk: Consultancy; Bayer: Honoraria. Suzuki:Chugai Pharmaceutical Co., Ltd: Research Funding, Speakers Bureau. Poloskey:Bioverativ: Employment. Rice:Bioverativ: Employment. Katragadda:Bioverativ: Employment. Rudin:Bioverativ: Employment, Equity Ownership. Fruebis:Bioverativ: Employment, Other: Clinical Development.

Download Full-text

The Atlanta Protocol: Immune Tolerance Induction in Pediatric Patients with Hemophilia a and Inhibitors on Emicizumab

Blood ◽

10.1182/blood-2018-99-114249 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 634-634 ◽

Cited By ~ 2

Author(s):

Glaivy M. Batsuli ◽

Karen L. Zimowski ◽

Kelly Tickle ◽

Shannon L. Meeks ◽

Robert F. Sidonio

Keyword(s):

Clinical Evaluation ◽

Immune Tolerance ◽

Half Life ◽

Research Funding ◽

Pediatric Patients ◽

Hemophilia A ◽

Tolerance Induction ◽

Advisory Board ◽

Third Generation ◽

Immune Tolerance Induction

Abstract Introduction: The formation of neutralizing anti-factor VIII (fVIII) antibodies, called inhibitors, is a challenging complication in hemophilia A care. While novel non-factor therapies significantly reduce bleeding symptoms in patients with hemophilia A and inhibitors, the absence of fVIII tolerance remains unchanged. Additionally, there are concerns regarding the hemostatic efficacy and safety of bypassing agents necessary for the management of breakthrough bleeds in patients with inhibitors on these novel therapies. Immune tolerance induction (ITI) remains the primary method for eradicating inhibitors and restoring the hemostatic response to fVIII. Here we report on the response to ITI in pediatric patients following initiation of the bispecific humanized monoclonal antibody Emicizumab. Methods: Patients between the ages of 1 - 11 years old with hemophilia A and an active inhibitor (≥0.6 Bethesda Units (BU)/mL) treated at the Emory Pediatric Hemophilia Treatment Center were included in this analysis. In general, ITI was initiated after four weekly loading doses of Emicizumab with standard or extended half-life recombinant (rfVIII) or plasma-derived (pdfVIII) fVIII at 100 units/kg three times per week. Factor choice was determined by the fVIII product used for the ITI attempt prior to initiation of Emicizumab or a standard half-life third generation rfVIII product if no prior ITI attempts. FVIII pharmacokinetics during ITI including the estimated fVIII half-life, fVIII incremental recovery of expected, and inhibitor titers were measured with chromogenic-based assays using bovine reagents. Bleeding symptoms and treatment regimens for bleeds/procedures were also monitored. Results: Eight patients are currently receiving ITI according to this Atlanta Protocol. Details regarding this cohort are outlined in Table 1. Three of the 8 patients required central venous access for ITI fVIII infusions. These eight patients have historical peak inhibitor titers, defined as the highest inhibitor titer prior to this ITI regimen, ranging from 2.0 - 198 BU/mL. Four patients have just recently started ITI. The other 4 patients (patients 1, 2, 4, and 5) have been treated with Emicizumab and ITI for a median duration of 15 weeks (range 13-18 weeks). Two of the 4 patients are on ITI with a standard half-life third generation rfVIII product, 1 is on a standard half-life third generation B domain deleted (BDD) rfVIII product, and 1 is on an extended half-life (EHL) rfVIII-Fc fusion product. Their last measured inhibitor titers after initiation of ITI range from 0.3 - 3.7 chromogenic BU (CBU). All inhibitor titers declined with the start of ITI, and none of the 4 patients experienced an amnestic response (Figure 1). The fVIII incremental recovery improved in 3 of the 4 patients from a median of 30% of expected (range 17-69%) prior to Emicizumab with ITI to 85% of expected (range 67-85%) at the last clinical evaluation. The 1 patient remaining has an fVIII incremental recovery <10% of expected at the last clinical evaluation. Only one patient has required treatment with a single dose of recombinant activated factor VII (rfVIIa) for a right knee hemarthrosis during ITI without complication. There were 3 additional mild bleeding symptoms in 2 patients that did not require intervention including 1 trauma-induced forehead hematoma that self-resolved and 2 episodes self-resolving epistaxis lasting <5 minutes. Two of the 4 patients reported no bleeding symptoms. There were no episodes of thrombosis or thrombotic microangiopathy. Conclusions: This is the first report detailing the Atlanta Protocol for ITI in hemophilia A patients with inhibitors receiving Emicizumab prophylaxis. Although early, these results suggest that ITI can be safely administered in these patients and is able to achieve continued improvement in clinical indicators of tolerance. Disclosures Batsuli: Bayer: Other: Advisory Board; Genentech: Other: Advisory Board; Octapharma: Other: Advisory Board. Zimowski:National Hemophilia Association/Shire: Other: Funding for clinical fellowship in Hemostasis/Thrombosis. Meeks:Bioverativ: Other: Advisory Board; Bayer: Other: Advisory Board; CSL Behring: Other: Advisory Board; Catalyst Biosciences: Other: Advisory Board; Genentech: Other: Advisory Board; HEMA Biologics: Other: Advisory Board; Shire: Other: Advisory Board; Pfizer: Research Funding. Sidonio:Genentech: Other: Advisory Board, Research Funding; Bioverativ: Other: Advisory Board, Research Funding; Biomarin: Other: Advisory Board; Novo Nordisk: Other: Advisory Board; Octapharma: Other: Advisory Board; Grifols: Other: Advisory Board, Research Funding; Uniqure: Other: Advisory Board; CSL Behring: Other: Advisory Board; Shire: Other: Advisory Board, Research Funding; Kedrion: Research Funding.

Download Full-text

Low-Dose Immune Tolerance Induction for Hemophilia a Children with Poor-Risk High-Titer Inhibitors

Blood ◽

10.1182/blood-2019-132021 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 1122-1122

Author(s):

Zekun Li ◽

Zhenping Chen ◽

Xiaoling Cheng ◽

Xinyi Wu ◽

Li Gang ◽

...

Keyword(s):

Success Rate ◽

Board Of Directors ◽

Immune Tolerance ◽

Low Dose ◽

Hemophilia A ◽

Tolerance Induction ◽

Advisory Committees ◽

Immune Tolerance Induction ◽

Inhibitor Titer

Background: Low-dose immune tolerance induction (ITI) +/- immunosuppression as a practical ITI strategy in China showed a relatively satisfactory success rate and economic advantages in pilot study. However, the outcome still needs to be verified by larger cohort. Aim: To report the efficacy of this low-dose ITI +/- immunosuppression strategy in hemophilia A children ≥ 10 BU. Methods: This was a single center, prospective study in 53 hemophilia A subjects from Sep 2016 to Apr 2019. All subjects having ≥ 10 BU receiving ~50IU/kg FVIII every other day using domestic intermediate purity pdFVIII/VWF products, either alone or in combination with rituximab and prednisone judging by inhibitors and ITI response. Results: Finally, 46 subjects received this strategy at a median of 3.2 (IQR, 2.3-6.5) years old, their pre-ITI inhibitor titer was median 30.0 (range, 10.1-416) BU. Analysis at median 15.1 (range 3.0-34.4) months follow-up, success (inhibitor <0.6BU) was achieved in 32 (69.6%) subjects, partial success (inhibitor <5BU but >0.6BU) in 11 (23.9%) subjects, and failure in 5 (10.9%) subjects. Between subjects administered ITI-alone and ITI- immunosuppression, no significant difference was observed in time to success (median 8.5; IQR 6.7-11.7 vs 10.2; IQR 5.1-25.1, P=0.164). The mean monthly bleeding rate on ITI was 0.49 which declined 59.3% compared with pre-ITI period. Subjects administered ITI-immunosuppression (0.54 ± 0.46) was higher than ITI-alone (0.42 ± 0.69) although with no significantly difference (P=0.089). Seven (21.9%) subjects experienced inhibitor recurrence, 4 subjects treated with ITI-alone, 3 with ITI-immunosuppression. Recurrence occurred at a median of 4.8 (range, 2.8-10.8) months after successful ITI with inhibitor titer transiently rising to median 0.7 (range, 0.7-1.5) BU. Conclusion: This low-dose ITI +/- immunosuppression therapy in subjects with pre-ITI inhibitor ≥ 10 BU showed a success rate similar to other high/intermediate-dose regimen for the whole inhibitor patients. The subjects treated with ITI-immunosuppression did not showed higher recurrence at present, while a longer time follow-up is still needed. Disclosures Poon: Roche: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bioverativ/Sanofi: Consultancy, Membership on an entity's Board of Directors or advisory committees; World Federation of Hemophilia: Other: Not-for-profit organization affiliation: volunteer ; Novo Nordisk: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participation in sponsored research; CSL-Behring: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Grant Funding; Bayer: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Grant Funding; Takeda/Shire: Consultancy, Membership on an entity's Board of Directors or advisory committees; Octapharma: Consultancy, Membership on an entity's Board of Directors or advisory committees.

Download Full-text

Breakthrough Bleeding in Hemophilia a Patients on Prophylaxis

Blood ◽

10.1182/blood.v128.22.2581.2581 ◽

2016 ◽

Vol 128 (22) ◽

pp. 2581-2581 ◽

Cited By ~ 2

Author(s):

Beth Boulden Warren ◽

Taylor Blades ◽

Natalie L Smith ◽

Michael Wang ◽

Marilyn J. Manco-Johnson

Keyword(s):

Factor Viii ◽

Board Of Directors ◽

Research Funding ◽

Hemophilia A ◽

Tolerance Induction ◽

Severe Hemophilia ◽

Advisory Committees ◽

Breakthrough Bleeding ◽

University Of Colorado ◽

The University

Abstract Background: Patients with severe hemophilia A (factor VIII (FVIII)<1%), as well as many patients with moderate hemophilia A (FVIII 1-5%), are treated intravenously with FVIII prophylaxis to prevent bleeding. However, breakthrough bleeding occurs in many patients. Methods: To better understand breakthrough bleeding, we evaluated the effect of hemophilia severity, prophylaxis adherence, and replacement FVIII utilization on bleeding rates in patients with hemophilia A on prophylaxis. Data on hemophilia severity and bleeding rates were collected from subjects with hemophilia A, ages 2-30 years, treated at the University of Colorado for hemophilia A, using the University of Colorado Clinical Research Bleeding Disorders Database (UCBDD). Adherence and FVIII utilization data were collected from a subset of subjects with hemophilia A on prophylaxis without active inhibitors who participated in the Centers for Disease Control/American Thrombosis and Hemostasis Network Community Counts (CDCCC) registry between December 2013 and June 2016, which surveyed participants about their estimated percentage of missed prophylaxis doses. The CDCCC registry was also used to corroborate bleeding rates. The effect of hemophilia severity and missed prophylaxis doses (percentage of prescribed doses) on bleeding rates were analyzed using logistic regression, with bleeding rates dichotomized as high or low relative to study population median bleeding rates. The relationship between weekly factor utilization and annualized bleeding rates was evaluated using Pearson's correlation. Results: Of 89 patients with severe hemophilia A in the UCBDD, 86.5% of patients were on continuous prophylaxis, with an additional 7.9% on immune tolerance induction. The 5.6% of patients with severe hemophilia on episodic treatment had been encouraged to use prophylaxis but had declined. Of 37 patients with moderate hemophilia A, 48.7% were on continuous prophylaxis. Sixty-nine subjects on prophylaxis had data in the UCBDD and the CDCCC registry collected during the defined time period. Bleeding rates are shown in Table 1. Prophylaxis doses in this population had an interquartile range of 74.3 to 120 units/kg/week (mean 96.9 units/kg/week), dosed 2-7 times per week depending on activities and historic bleeding patterns. Eighty-two percent of patients rated their percentage of missed prophylaxis doses at <10%, 11.6% rated their missed doses at 10-20%, 2.9% rated their missed doses at 21-50%, and 2.9% rated missed doses at >50%. There was not a statistically significant relationship between any bleeding rate and percentage of missed doses, hemophilia severity, or factor utilization, as shown graphically in figures 1 and 2. Conclusion: Although prophylaxis usage and adherence were excellent, breakthrough bleeding was common, with breakthrough joint bleeding occurring in 36% of subjects, and was not related to FVIII dose per week. Prospective studies are needed to better determine individually tailored prophylaxis regimen using dose, product class, and timing with activities, in order to achieve more effective prophylaxis. Table 1 Bleeding Rates on Continuous Prophylaxis. No intracranial or gastrointestinal hemorrhages were recorded in this population. Table 1. Bleeding Rates on Continuous Prophylaxis. No intracranial or gastrointestinal hemorrhages were recorded in this population. Figure 1 Relationship between Bleeding Rates, Hemophilia Severity and Adherence Figure 1. Relationship between Bleeding Rates, Hemophilia Severity and Adherence Figure 2 No correlation was found between bleeding rates and factor VIII utilization as measured in units per kg per week. Figure 2. No correlation was found between bleeding rates and factor VIII utilization as measured in units per kg per week. Disclosures Warren: HTRS/Novo Nordisk: Research Funding; Bayer Hemophilia Awards Program: Research Funding. Wang:Biogen: Membership on an entity's Board of Directors or advisory committees; CSL Behring: Membership on an entity's Board of Directors or advisory committees; Baxalta: Membership on an entity's Board of Directors or advisory committees; HEMA Biologics: Membership on an entity's Board of Directors or advisory committees; LFB: Membership on an entity's Board of Directors or advisory committees; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees. Manco-Johnson:Baxalta: Honoraria; NovoNordisk: Honoraria; BiogenIdec: Honoraria; Bayer: Honoraria, Research Funding; CSL Behring: Honoraria.

Download Full-text

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.

Download Full-text

Treatment of Haemophilia a (HA) Patients with Inhibitors: Immune Tolerance Induction with a Single Factor VIII/Von Willebrand Factor Concentrate in an Observational Immune Tolerance Induction Study (ObsITI)

Blood ◽

10.1182/blood-2018-99-114408 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 2482-2482

Author(s):

C. Escuriola Ettingshausen ◽

Erik Berntorp ◽

Yesim Dargaud ◽

Zeynep Gutowski ◽

Claude Negrier ◽

...

Keyword(s):

Board Of Directors ◽

Von Willebrand Factor ◽

Immune Tolerance ◽

Research Funding ◽

Tolerance Induction ◽

Advisory Committees ◽

Immune Tolerance Induction ◽

Inhibitor Titre ◽

Von Willebrand ◽

Willebrand Factor

Abstract Introduction and objectives: Development of neutralising inhibitors against factor VIII (FVIII) is one of the most serious and costly complications in the treatment of HA. An ongoing international, open-label, uncontrolled, multicentre observational study, ObsITI (ClinicalTrials.gov. NCT 02207894) started in 2005 to assess immune tolerance induction (ITI), the standard of care in patients with inhibitors. The study evaluates patient- and therapy-related variables on ITI course, outcome and morbidity in HA patients with inhibitors. ObsITI satellite studies additionally look at other factors related to tolerisation. Methods and Materials: As of February 2018, 193 patients from 20 countries undergoing ITI have been recruited in ObsITI. 152 patients completed the study and 41 are ongoing. A subgroup of more than 80 prospective patients were treated exclusively during the complete ITI course with a single plasma-derived (pd) FVIII concentrate that contains von Willebrand factor (VWF) in a VWF/FVIII ratio of 0.4 (Octapharma AG). According to the recommended Bonn protocol, low responders at ITI start received 50-100 IU FVIII kg-1 daily, or every other day; high responders received 100 IU FVIII kg-1 every 12 hours. Results: In this ongoing study, the majority of patients treated with the pdFVIII/VWF product achieved a negative inhibitor titre. ITI outcome was significantly correlated with the bleeding rate during ITI, the peak titre during ITI, the inhibitor titre at start of ITI >10 BU, and the number of poor prognosis factors. Conclusion: Treatment with this particular pdFVIII/VWF concentrate, mainly according to the Bonn protocol, resulted in a high ITI success rate in HA patients with inhibitors and corroborates previously published success rates (77.1% complete/partial success in 48 inhibitor patients undergoing ITI with the same product). Disclosures Escuriola Ettingshausen: SOBI: Honoraria, Research Funding; Shire: Honoraria, Research Funding; Biotest: Honoraria, Research Funding; Octapharma: Honoraria, Research Funding; CSL Behring: Honoraria, Research Funding; Novo Nordisk: Honoraria; Roche: Honoraria; Grifols: Honoraria; Pfizer: Honoraria; LFB: Honoraria. Berntorp:Octapharma: Consultancy; CSL Behring: Consultancy; Shire: Consultancy, Other: honoraria for lecturing . Negrier:Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Octapharma: Honoraria, Research Funding; CSL Behring: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Alnylam: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; LFB: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sobi/Bioverativ: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novo Nordisk: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Baxalta/Shire: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: Honoraria, Research Funding. Pavlova:Novo Nordisk: Honoraria; Octapharma: Honoraria. Oldenburg:Chugai: Honoraria, Membership on an entity's Board of Directors or advisory committees; Grifols: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Biogen Idec: Honoraria, Membership on an entity's Board of Directors or advisory committees; Shire: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Octapharma: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novo Nordisk: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; CSL Behring: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Biotest: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Swedish Orphan Biovitrum: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.

Download Full-text

Lack of Inhibitor Development in the American Thrombosis and Hemostasis Network (ATHN)-2 Factor Switching Study: Preliminary Report of Primary Outcome

Blood ◽

10.1182/blood-2019-128612 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 1114-1114

Author(s):

Robert F. Sidonio ◽

Dunlei Cheng ◽

Christine Guelcher ◽

Janna M. Journeycake ◽

Susan U Lattimore ◽

...

Keyword(s):

Factor Viii ◽

Board Of Directors ◽

Half Life ◽

Research Funding ◽

Primary Outcome ◽

Hemophilia A ◽

Advisory Board ◽

Severe Hemophilia ◽

Advisory Committees ◽

Inhibitor Development

Introduction: With many standard half-life (SHL) and extended half-life (EHL) recombinant factor VIII and factor IX products licensed in the US over the last 6 years, it is likely that previously treated patients (PTPs) will consider switching to a new EHL FVIII or FIX product. Although past product switching surveillance suggests no increased inhibitor development risk, there is the need for a real-world data on the incidence of inhibitor development following switching from SHL to EHL rFVIII or rFIX in PTPs with hemophilia A and B. Methods: A longitudinal, observational study of participants with Hemophilia A or B who switched to a rFVIII or rFIX concentrate licensed after Jan 1, 2013. The study included retrospective (switched within 50 exposure days (EDs) and prospective arms. Participants were recruited from ATHN-affiliated Hemophilia Treatment Centers (HTCs). The primary outcome measure was the development of a new inhibitor (i.e. neutralizing antibodies to factor VIII or IX) a 1 year or during the 50 EDs following the product switch. Plasma samples were collected at baseline, 10 EDs and 50 EDs. Inclusion criteria include moderate or severe hemophilia A/B currently on a plasma-derived or recombinant FVIII or FIX concentrate with planned or recent switch to an EHL FVIII or FIX concentrate approved after Jan 1, 2013. Participants with an active inhibitor at time of enrollment or undergoing ITI or switched to a non-factor product were excluded. Results: 303 hemophilia participants from 27 treatment centers were enrolled from 2015 to June 2019. The median age at enrollment was 17 years (IQR 10-32 years). 300 of 303 participants were male, Caucasian (72.6%) and had private insurance (44.9%). 74.3% were FVIII deficient and 25.7% were FIX deficient. Most had severe hemophilia A or B, 82.3% (n=237) and 12.8% (n=37) had a prior history of inhibitor but were negative at the time of enrollment. Prior to the switching, 92.1% (n=197) and 7.9% (n=17) of hemophilia A participants took standard rFVIII or pdFVIII respectively, while 87.8% (n=65) and 12.2% (n=9) of hemophilia B participants took standard rFIX or pdFIX, respectively. The three most frequent switching reasons were extended half-life consideration (n=192; 66.7%), a desire for a longer acting version (n=55; 19.1%) and less than expected clinical response to the current product (n=15; 5.2%). Among 214 participants with hemophilia A, 182 (85.0%) switched to FVIII EHL products while 23 (10.7%) switched to new SHL FVIII. For nine patients (4.2%) switching product information was not available. 72 out of 74 (97.3%) participants with hemophilia B that switched products, switched to an EHL rFIX. Eleven hemophilia participants (six A and five B) entered a second cycle of switching after the completion of the first switching cycle. Following that, four switched to FVIII EHL products, two to new SHL rFVIII and five to rFIX EHL products. A total of 193 (63.7%; 148 FVIII, 45 FIX) participants completed the clinical trial while 36 (11.9%; 26 FVIII, 10 FIX) did not complete the trial and 74 (24.4%) are ongoing in the trial. None of 303 (0%) enrolled participants developed an inhibitor, the primary outcome for this study, through data updated 6/2019. Variability was noted in per-site enrollment. The median enrollment per Hemophilia Treatment Center (HTC) was 10, the IQR was 7-16 with a range of 1-31. The types of factors associated with patients switches are summarized in the figure. Conclusion: No new inhibitors were noted among 303 moderate/severe hemophilia A/B PTPs without active inhibitors at entry, who switched factor VIII or IX products over 50 exposure days or 12 months. This result provides real-world evidence of the rarity of inhibitor development after a product switch in PTPs. The study also achieved a key logistical objective: to demonstrate feasibility of a prospective observational study across ATHN sites. Figure Legend: Factor types to which ATHN-2 patients switched during the study. Disclosures Sidonio: Grifols: Membership on an entity's Board of Directors or advisory committees, Research Funding; Uniqure: Membership on an entity's Board of Directors or advisory committees; Kedrion: Research Funding; Takeda-Shire: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bioverativ: Membership on an entity's Board of Directors or advisory committees, Research Funding; Octapharma: Membership on an entity's Board of Directors or advisory committees, Research Funding; Biomarin: Membership on an entity's Board of Directors or advisory committees; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees; Genetech: Membership on an entity's Board of Directors or advisory committees, Research Funding. Guelcher:Takeda: Other: Advisory Board; Genetech: Other: Advisory Board; NovoNordisk: Other: Advisory Board; Octapharma: Other: Advisory Board. Takemoto:genentech: Membership on an entity's Board of Directors or advisory committees; novartis: Other: DSMB membership. Tarantino:Novo Nordisk: Consultancy, Honoraria, Research Funding, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Michael Tarantino, MD SC: Other: President, Owner- Private Practice ; Magellan Healthcare: Consultancy; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Clinical Trial PI, Speakers Bureau; Roche: Consultancy; Grifols: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Bleeding and Clotting Disorders Institute: Employment; Genentech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Honoraria, Other: Grant Reviewer , Research Funding; Octapharma: Consultancy, Speakers Bureau. Neufeld:Octapharma, Agios, Acceleron, Grifols, Pfizer, CSL Behring, Shire Pharmaceuticals (Baxalta), Novo Nordisk, ApoPharma, Genentech, Novartis, Bayer Healthcare: Consultancy; Octapharma, Shire Pharmaceuticals (Baxalta), Novo Nordisk, Celgene, NHLBI/NIH: Research Funding; Octapharma: Other: study investigator, NuProtect study (Octapharma-sponsored).

Download Full-text