First-in-human Gene Therapy Study of AAVhu37 Capsid Vector Technology in Severe Hemophilia A

Background: Gene therapy for hemophilia A has the potential to reduce the treatment burden for care-providers and patients, by eliminating the need for regular factor VIII (FVIII) prophylaxis through the long-term expression of endogenous FVIII at levels sufficient to provide bleed protection. BAY 2599023 (AAVhu37FVIII) is a non-replicating adeno-associated virus (AAV) vector, based on the AAV serotype hu37, which contains a single-stranded DNA genome encoding a B-domain deleted FVIII, under the control of a liver-specific promotor/enhancer combination optimized for transgenic expression. The AAVhu37 capsid is a member of the hepatotropic Clade E family and has been selected based on nonclinical studies demonstrating efficient liver-directed FVIII gene transfer, favorable biodistribution as well as durable FVIII expression. BAY 2599023 is the first clinical-stage AAV gene therapy vector based on the AAVhu37 serotype. This analysis reports safety and FVIII activity following a single intravenous infusion of BAY 2599023 in the first-dose cohort of a phase I/II open-label, first time in human dose-finding study (NCT03588299) of previously treated, severe hemophilia A patients. Patients/Methods: Two participants were enrolled sequentially; each received a single infusion of AAVhu37 (0.5 x 1013 GC/kg). Patients were males ≥18 years with no history of FVIII inhibitor development, no detectable immunity to the AAVhu37 capsid, and >150 exposure days to FVIII products. Primary endpoints were adverse events (AEs), serious AEs and AEs/SAEs of special interest (S/AESI); the secondary endpoint was change in FVIII activity from baseline. Informed patient consent, and ethics committee approval at each local site, were obtained. Results: Following more than 15 weeks of safety observation, no SAEs, AEs related to study drug, nor S/AESI were reported. Liver enzymes (alanine aminotransferase and aspartate aminotransferase) remained <1.5 of baseline. Corticosteroids were not used in either patient. Clear evidence of FVIII expression was observed in both patients with stable values of ~5% and ~17% in the first and second patient, respectively. An early read-out also indicated hemostatic efficacy in both; the first patient had successfully halted prophylaxis for 6 weeks, while the second one, treated on-demand with 99 bleeds recorded in the 12 months prior to gene transfer, has been bleed free for over 5.5 months to date. Conclusions: BAY 2599023 was previously shown in non-clinical studies to have a good safety profile, with the potential to achieve endogenous expression of FVIII at therapeutic levels, over an extended period of time. In this first-in-human clinical study with BAY 2599023, two patients have been treated with BAY 2599023 at the starting dose of 0.5 x 1013 GC/kg and no safety concerns have been reported to date. Measurable expression of endogenous FVIII and an early read-out of hemostatic efficacy have been demonstrated in both patients. Overall, data generated from this first dose cohort demonstrate that successful translation from pre-clinical to clinical development and proof-of-mechanism for BAY 2599023 was achieved. Disclosures Pipe: HEMA Biologics: Consultancy; Shire: Consultancy; Roche/Genentech: Consultancy; Sanofi: Consultancy; Freeline: Consultancy; Apcintex: Consultancy; Novo Nordisk: Consultancy; Catalyst Bioscience: Consultancy; CSL Behring: Consultancy; Bayer: Consultancy; uniQure: Consultancy; BioMarin: Consultancy; Pfizer: Consultancy; Spark Therapeutics: Consultancy. Becka:Bayer: Employment. Detering:Bayer: Employment. Vanevski:Bayer: Employment. Lissitchkov:Octapharma: Equity Ownership, Research Funding; Bayer: Consultancy, Equity Ownership, Honoraria, Other: Principal investigator for clinical trials, Research Funding; Sobi: Consultancy, Equity Ownership, Honoraria; Sanofi: Equity Ownership, Research Funding; Roche: Consultancy, Equity Ownership, Honoraria, Speakers Bureau; Shire: Consultancy, Equity Ownership, Honoraria, Speakers Bureau. OffLabel Disclosure: Gene therapy for haemophilia treatment.

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Updated Follow-up of the Alta Study, a Phase 1/2 Study of Giroctocogene Fitelparvovec (SB-525) Gene Therapy in Adults with Severe Hemophilia a

Blood ◽

10.1182/blood-2020-137648 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 12-12

Author(s):

Andrew D. Leavitt ◽

Barbara A. Konkle ◽

Kimo Stine ◽

Nathan Visweshwar ◽

Thomas J. Harrington ◽

...

Keyword(s):

Gene Therapy ◽

Stock Options ◽

Research Funding ◽

Hemophilia A ◽

Phase 1 ◽

Severe Hemophilia ◽

Bleeding Events ◽

Dose Cohort ◽

Fviii Activity

Introduction: Hemophilia A is a rare bleeding disorder caused by pathogenic variants in the F8 gene, resulting in insufficient factor VIII (FVIII) activity. Adeno-associated virus (AAV)-mediated gene transfer enables the delivery of a modified functional F8 gene to hepatocytes that subsequently synthesize FVIII at levels that may prevent bleeding events in the absence of exogenous FVIII. Updated results and follow-up from the Alta study, an ongoing gene therapy study in patients with severe hemophilia A, are presented. Methods: The Alta study is a phase 1/2 dose-ranging, single-dose study of giroctocogene fitelparvovec (also known as SB-525 and PF-07055480), a recombinant AAV serotype 6 (rAAV6) vector encoding a modified F8 gene. Adults aged ≥18 years with severe hemophilia A were eligible for inclusion. Giroctocogene fitelparvovec was infused into patients in 4 cohorts of 2 patients each across 4 ascending doses (9e11, 2e12, 1e13, and 3e13 vg/kg). The 3e13 vg/kg dose cohort was expanded with 3 additional patients. Key end points included safety, circulating FVIII activity, use of FVIII replacement therapy, and frequency of bleeding events. Presented data are from the ongoing Alta study (NCT#03061201; data cutoff date, 26 May 2020; database not locked; data reflect those at time of data cutoff, have not undergone standard quality checks, and may be subject to change). Results: Eleven male patients participated in the study (mean [SD] age, 30.3 [7.8] years; white, 81.8%). As of the cutoff date, patients have been followed for 35 to 144 weeks; one patient in the 1e13 vg/kg cohort discontinued from the study. Overall, the most commonly reported adverse events (AEs; n) included increased alanine aminotransferase (ALT; 8 [72.7%]), increased aspartate aminotransferase (AST; 5 [45.5%]), upper respiratory tract infection (4 [36.4%]), and pyrexia (4 [36.4%]). Treatment-related serious AEs were reported in 1 patient (in the 3e13 vg/kg cohort) who experienced hypotension and fever ≈6 hours after giroctocogene fitelparvovec infusion; the events fully resolved with treatment and did not delay post-infusion discharge. In the 3 lower-dose cohorts, no ALT elevation requiring more than 7 days of corticosteroid treatment was observed. Of the 5 patients in the 3e13 vg/kg cohort, 4 had elevations in ALT that were managed with a tapering course of corticosteroids (ranging from 10-134 days) without loss of clinically relevant FVIII activity through 40 weeks, as evidenced by a lack of bleeding events before and after treatment with corticosteroids. Increases in FVIII activity from baseline were generally dose-dependent. Patients in the 3e13 vg/kg cohort achieved a mean normal-range of FVIII activity within 5 weeks post-infusion, with mean FVIII activity maintained through week 40, which is the last time point with data for all 5 patients in this cohort (Table). Following the initial prophylactic period of up to ≈3 weeks after giroctocogene fitelparvovec administration, no bleeding events occurred in any patient treated in the 3e13 vg/kg cohort. Use of FVIII replacement therapy ≥3 weeks after giroctocogene fitelparvovec administration was reported in 5/6 patients in the lower-dose cohorts (range: 9-115 infusions); none of the patients in the 3e13 vg/kg cohort required FVIII replacement beyond initial use of prophylactic factor for up to ≈3 weeks (prophylactic coverage stopped 3 weeks and 2 days after giroctocogene fitelparvovec administration in 1 patient in the 3e13 vg/kg cohort). Conclusions: To date, a single infusion of giroctocogene fitelparvovec gene therapy in patients with severe hemophilia A resulted in dose-dependent and sustained increases in FVIII levels without administration of exogenous FVIII, bleeding episodes or sustained adverse events in the highest-dose cohort (3e13 vg/kg). Additionally, patients treated in the highest-dose cohort achieved a mean FVIII activity in the normal range within 5 weeks, which was maintained through week 40. Data on all patients with more than 1 year of follow-up will also be presented. The study is ongoing, and these interim results support further development of giroctocogene fitelparvovec for the treatment of patients with severe hemophilia A. Disclosures Leavitt: BioMarin: Membership on an entity's Board of Directors or advisory committees. Konkle:Sanofi: Consultancy, Research Funding; Takeda: Research Funding; Uniquire: Research Funding; CSL Behring: Consultancy; BioMarin: Consultancy; Baxalta: Research Funding; Spark: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Sigilon: Consultancy, Research Funding; Roche: Consultancy. Stine:Biomarin: Consultancy; Applied Stem Cell Therapeutics: Consultancy. Visweshwar:Biogen Idec: Membership on an entity's Board of Directors or advisory committees. Giermasz:uniQure: Consultancy, Research Funding; Sangamo Therapeutics: Research Funding; Bioverativ/Sanofi: Consultancy, Research Funding, Speakers Bureau; BioMarin: Consultancy, Research Funding, Speakers Bureau; Genentech/Roche: Consultancy, Research Funding, Speakers Bureau. Arkin:Pfizer: Current Employment, Current equity holder in publicly-traded company, Other: own stock/options in the company. Fang:Pfizer Inc.: Current Employment, Other: own stock/options in the company. Plonski:Pfizer Inc.: Current Employment, Other: own stock/options in the company. Smith:Pfizer Inc.: Current Employment, Other: own stock/options in the company. Tseng:Pfizer Inc.: Current Employment, Other: own stock/options in the company. Di Russo:Pfizer Inc.: Current Employment, Other: own stock/options in the company. Cockroft:Sangamo Therapeutics: Current Employment, Other: Shareholder of Sangamo Therapeutics. Rupon:Pfizer Inc.: Current Employment, Other: own stock/options in the company. Rouy:Sangamo Therapeutics: Current Employment, Other: Shareholder of Sangamo Therapeutics.

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Updated Follow-up of the Alta Study, a Phase 1/2, Open Label, Adaptive, Dose-Ranging Study to Assess the Safety and Tolerability of SB-525 Gene Therapy in Adult Patients with Severe Hemophilia A

Blood ◽

10.1182/blood-2019-122143 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 2060-2060 ◽

Cited By ~ 1

Author(s):

Barbara A. Konkle ◽

Kimo Stine ◽

Nathan Visweshwar ◽

Thomas J. Harrington ◽

Andrew D. Leavitt ◽

...

Keyword(s):

Gene Therapy ◽

Hemophilia A ◽

High Dose ◽

Severe Hemophilia ◽

Bleeding Events ◽

Employment Equity ◽

Dose Cohort ◽

Fviii Activity ◽

Equity Ownership

Introduction: Hemophilia A is a rare blood disorder caused by an F8 variant resulting in insufficient Factor VIII (FVIII) activity. Updated results and follow-up of an ongoing gene therapy study in patients with severe hemophilia A are presented. Methods: The Alta study is a dose-ranging, single-dose study of SB-525 gene therapy, a recombinant adeno-associated virus (rAAV6) vector encoding an F8 gene. SB-525 was injected into 11 patients in 4 cohorts of 2 patients each across 4 ascending doses (9e11, 2e12, 1e13 and 3e13 vg/kg) with expansion of the high dose cohort by 3 additional patients. Endpoints included: safety events, changes in circulating FVIII activity, FVIII antigen, FVIII usage, and frequency and severity of bleeding. Results: In the third cohort (1e13 vg/kg), a single infusion of SB-525 resulted in stable and clinically relevant increases in FVIII activity. Patients in the fourth cohort (high dose, 3e13 vg/kg) achieved FVIII levels within the normal range (Table 1), with no bleeding events reported up to 24 weeks post-injection. Patients treated at 3e13 vg/kg did not require FVIII replacement therapy following the initial prophylactic period of up to approximately 3 weeks post-SB-525 administration. No bleeding events were observed in any of the patients treated at the 3e13 vg/kg dose. One patient had a treatment-related serious adverse event of hypotension and fever, with symptoms of headache and tachycardia, which occurred ~6 hours after completion of the vector infusion and resolved with treatment within 24 hours. In the three first cohorts, no ALT elevation requiring more than 7 days of corticosteroid treatment was observed. Of the 5 patients treated to date in the high dose cohort, 3 followed for at least 8 weeks showed transient and mild (grade 1) ALT elevations. All responded to corticosteroids within one week. At the time of abstract submission, all patients were off corticosteroids. FVIII antigen was assessed by ELISA, and preliminary results from the high dose cohort showed a good correlation by chromogenic assay between the specific activity of SB-525 derived FVIII and Xyntha, a recombinant B-domain deleted protein control. Dosing in the fourth cohort is ongoing, and additional analyses of the trial data including FVIII levels, bleeding rate and factor usage will be presented as available. Four- to 11-month follow-up data on all patients in the fourth dose cohort will also be presented. Conclusions: To date, treatment with a single infusion of SB-525 gene therapy resulted in dose-dependent and sustained increases in FVIII levels, with a substantial decrease in FVIII usage, and no bleeding episodes recorded in the highest dose cohort. Patients treated in the highest dose cohort achieved FVIII activity in the normal range. No ALT elevations persisting longer than 7 days were observed in the first three dose cohorts. The study is ongoing, and the results support further development of SB-525 for the treatment of severe Hemophilia A. Disclosures Giermasz: uniQure: Consultancy, Other: Research; Sangamo: Other: Research; Bioverativ/Sanofi: Consultancy, Speakers Bureau; BioMarin: Consultancy, Other: Research; Genentech/Roche: Consultancy, Other: Research, Speakers Bureau. Arkin:Pfizer: Employment, Equity Ownership. Di Russo:Pfizer: Employment, Equity Ownership. Snyder:Sangamo Therapeutics: Employment. Woolfson:Sangamo Therapeutics: Employment, Equity Ownership. Rouy:Sangamo Therapeutics: Employment, Equity Ownership.

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Phase 1 Repeat Dosing with BIVV001: The First Investigational Factor VIII Product to Break through the Von Willebrand Factor-Imposed Half-Life Ceiling

Blood ◽

10.1182/blood-2019-122211 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 625-625 ◽

Cited By ~ 2

Author(s):

Toshko Lissitchkov ◽

Kara Rice ◽

Suresh Katragadda ◽

Annemieke Willemze ◽

Craig Benson ◽

...

Keyword(s):

Half Life ◽

Research Funding ◽

Hemophilia A ◽

Phase 1 ◽

Geometric Mean ◽

Activity Levels ◽

Severe Hemophilia ◽

Fviii Activity ◽

Equity Ownership ◽

Von Willebrand

Introduction The use of factor VIII (FVIII) replacement products enables comprehensive management (prophylaxis, acute bleed control, and perioperative hemostasis) of patients with severe hemophilia A. Prophylaxis with standard half-life FVIII replacement therapies requires frequent administration, and low FVIII activity levels between infusions lead to an increased risk of bleeds. FVIII replacement products that achieve optimal bleed protection with once-weekly dosing intervals remain an unmet need for people living with severe hemophilia A. BIVV001 (rFVIIIFc-VWF-XTEN) is a novel FVIII therapy composed of single-chain FVIII, the Fc domain of human immunoglobulin G1, the FVIII-binding D′D3 domain of von Willebrand factor (VWF), and 2 XTEN polypeptides. BIVV001 is designed to be a next-generation FVIII therapy that circulates independently of endogenous VWF, thereby breaking the VWF-imposed half-life ceiling. Single-dose BIVV001 was well tolerated and provided sustained FVIII activity in a first-in-human trial (Konkle et al, Blood, 2018). Here, we report final data for an open-label Phase 1 trial to assess the safety, tolerability, and pharmacokinetics (PK) of repeat dosing with BIVV001 in subjects with severe hemophilia A (<1 IU/dL [<1%] endogenous FVIII) (EudraCT No: 2018-001535-51). Methods Eligible subjects were 18-65 years of age, had severe hemophilia A, and ≥150 exposure days to prior FVIII products. After screening and washout, subjects received 4 once-weekly doses of BIVV001 (Days 1, 8, 15, and 22) at either 50 IU/kg (Cohort 1) or 65 IU/kg (Cohort 2). The safety observation period extended for 28 days after the last dose of BIVV001. Primary endpoints were the occurrence of adverse events and clinically significant abnormalities in laboratory tests, including inhibitor development. Secondary endpoints were PK parameters derived from FVIII activity evaluated using a one-stage activated partial thromboplastin time clotting assay. PK blood samples were collected immediately before BIVV001 infusion on Days 1, 8, 15, and 22 and at multiple times after dosing on Days 1 and 22. Results All subjects enrolled in Cohort 1 (n=10) and Cohort 2 (n=14) completed the study. Mean (range) age of subjects was 35 (25-55) years for Cohort 1 and 41 (24-58) years for Cohort 2. BIVV001 was well tolerated. No inhibitor development to FVIII was detected, and there were no events of hypersensitivity or anaphylaxis reported. Baseline-corrected PK data were available for 9 subjects in Cohort 1 and all subjects in Cohort 2. Consistent with the single-dose study, the geometric mean (range) half-life for 50 IU/kg and 65 IU/kg BIVV001 was 41.3 (34.2-50.1) hours and 37.3 (28.9-43.8) hours, respectively. After 4 weekly doses of BIVV001 (Day 22), geometric mean (range) area under the activity-time curve from hour 0 over the dosing interval (AUC0-tau) and maximum concentration at steady state (Cmaxss) of BIVV001 were 8290 (5810-10,300) hr × IU/dL and 131 (96-191) IU/dL for Cohort 1 and 11,200 (7040-15,800) hr × IU/dL and 171 (118-211) IU/dL for Cohort 2, respectively. Mean (standard deviation) FVIII activity immediately prior to the final dose of BIVV001 (Ctrough) was 9.9 (2.8) IU/dL in Cohort 1 and 11.7 (5.5) IU/dL in Cohort 2. The mean (range) Day 22-Day 1 accumulation index was 1.07 (1.03-1.11) for Cohort 1 and 1.05 (1.02-1.08) for Cohort 2. At 5 and 7 days after the final BIVV001 infusion, mean steady-state FVIII activity was 22% and 10% for Cohort 1 and 27% and 12% for Cohort 2, respectively (Figure). Geometric mean (range) incremental recovery after the first dose of BIVV001 was 2.3 (1.6-2.8) IU/dL per IU/kg for Cohort 1 and 2.4 (1.6-3.3) IU/dL per IU/kg for Cohort 2. Conclusions Four weekly infusions of 50 IU/kg or 65 IU/kg BIVV001 were well tolerated with no identified safety concerns. FVIII activity levels were sustained and nonaccumulating between doses. By breaking through the VWF-imposed half-life ceiling, BIVV001 prophylaxis may lead to more optimal, extended protection against bleeds for patients with severe hemophilia A than standard FVIII therapies. These results support the continued development of BIVV001 in a Phase 3 clinical trial program. Disclosures Lissitchkov: Roche: Consultancy, Equity Ownership, Honoraria, Speakers Bureau; Sanofi: Equity Ownership, Research Funding; Bayer: Consultancy, Equity Ownership, Honoraria, Other: Principal investigator for clinical trials, Research Funding; Sobi: Consultancy, Equity Ownership, Honoraria; Shire: Consultancy, Equity Ownership, Honoraria, Speakers Bureau; Octapharma: Equity Ownership, Research Funding. Rice:Sanofi: Employment. Katragadda:Sanofi: Employment. Willemze:Sanofi: Employment. Benson:Sanofi: Employment. Knobe:Sanofi: Employment.

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Severe Bleeding Events in Hemophilia Α Patients Receiving Emicizumab Prophylaxis

Blood ◽

10.1182/blood-2019-126659 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 1126-1126

Author(s):

Karen L. Zimowski ◽

Glaivy M. Batsuli ◽

Paulette Bryant ◽

Jenny McDaniel ◽

Kelly Tickle ◽

...

Keyword(s):

Board Of Directors ◽

Research Funding ◽

Hemophilia A ◽

Severe Bleeding ◽

Severe Hemophilia ◽

Bleeding Events ◽

Advisory Committees ◽

Acute Bleeding ◽

Fviii Activity ◽

Bleeding Episodes

Introduction : Emicizumab is a novel humanized bispecific antibody that mimics the function of activated coagulation factor VIII (fVIII). It has significantly changed the management of patients with hemophilia A and inhibitors by achieving baseline hemostatic control. Based on the HAVEN studies, emicizumab markedly reduces annualized bleeding rates and is FDA-approved for prophylaxis in hemophilia A patients of all ages, regardless of inhibitor status. In the HAVEN2 interim analysis, only 3/57 pediatric patients receiving emicizumab prophylaxis required treatment for an acute bleeding event after a 9-week median observation time. We report 3 patients with severe hemophilia A and a history of inhibitors receiving emicizumab prophylaxis with severe or refractory bleeding episodes to highlight the importance of vigilance and surveillance of children with severe hemophilia A on emicizumab. Methods: This retrospective analysis includes patients between 0-21 years of age with severe hemophilia A (fVIII activity < 1%) receiving emicizumab prophylaxis and admitted for the management of an acute bleeding episode following emicizumab's FDA approval in November 2017. Patients were followed at the Pediatric Hemophilia Treatment Center at the Hemophilia of Georgia Center for Bleeding & Clotting Disorders of Emory and the St. Jude Affiliate Clinic at Novant Health Hemby Children's Hospital. Data collected included demographics, past medical history including inhibitor status, bleeding history, and treatment modalities, and details regarding the presentation, management, and outcome of acute severe bleeding events. Due to the nature of the study, descriptive statistics were primarily used for data analysis. Results: Three patients with severe hemophilia A receiving emicizumab prophylaxis were admitted for the management of 4 severe bleeding episodes. All patients had a history of a fVIII inhibitor. Three of the 4 bleeding episodes were trauma-induced while 1 occurred spontaneously. For the traumatic episodes, all patients presented with worsening symptoms approximately 1 week following the inciting event. All patients had a normal aPTT at the time of presentation, ruling out a significant anti-drug antibody (emicizumab level not available). A patient with a low-titer inhibitor developed an epidural hematoma following a trampoline injury and was treated with continuous infusion of recombinant factor VIII (rfVIII), adjusting the rate to achieve chromogenic fVIII activity of 100% for 14 days. Following 14 days, he was started on rfVIII 50 IU/kg Q12 hours with a goal fVIII activity of 50%. His rfVIII dosing interval was gradually weaned to every other day while in inpatient rehabilitation. As outlined in Table 1, the remaining 3 bleeding events were initially managed with recombinant activated factor VII (rfVIIa) dosed at 80-90 mcg/kg/dose with escalating frequency for an average of 8 days. However, due to lack of improvement, treatment was changed to low-dose activated prothrombin complex concentrates (aPCC; 10-15 IU/kg/dose Q12-24 hours for an average of 7 days). In all 3 of these events, the hematomas improved after treatment with aPCC. No patient experienced thrombotic microangiopathy, thrombosis, or had evidence of DIC while receiving these treatment regimens. Discussion/Conclusion: Pharmacokinetic analysis of emicizumab suggests that following the standard 4-week loading phase, trough plasma emicizumab concentrations obtained prior to a 1.5 mg/kg once weekly maintenance dose correlates with at least 10-15 IU/dL equivalent fVIII activity. This degree of thrombin generation should be sufficient to prevent severe spontaneous bleeding episodes in most patients. However it does not preclude significant trauma-induced bleeding or spontaneous bleeding in inhibitor patients. Based on our cases, providers should maintain a high index of suspicion for acute bleeding in patients receiving emicizumab prophylaxis. Serious bleeding events, although rare, may have a more insidious onset in patients receiving emicizumab. Furthermore, despite the baseline hemostasis achieved with emicizumab, acute bleeding events may still require aggressive therapy. Our cases suggest that low-dose aPCC or continuous infusion fVIII may be feasible options for treating acute bleeding events in patients with hemophilia A and inhibitors receiving emicizumab prophylaxis. Disclosures Zimowski: Pfizer: Research Funding; National Hemophilia Foundation: Other: Medical Loan Reimbursement, Research Funding. Batsuli:Octapharma: Membership on an entity's Board of Directors or advisory committees; Bayer: Membership on an entity's Board of Directors or advisory committees; Genetech: Membership on an entity's Board of Directors or advisory committees. Bryant:Novo Nordisk: Other: PI on Novo Nordisk sponsored Studies. McDaniel:Genentech: Membership on an entity's Board of Directors or advisory committees. Tickle:National Hemophilia Foundation: Research Funding. Meeks:Bayer: Membership on an entity's Board of Directors or advisory committees; Genentech: Membership on an entity's Board of Directors or advisory committees; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees; Bioverativ: Membership on an entity's Board of Directors or advisory committees; Takeda-Shire: Membership on an entity's Board of Directors or advisory committees; HEMA Biologics: Membership on an entity's Board of Directors or advisory committees. Sidonio:Genetech: Membership on an entity's Board of Directors or advisory committees, 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; Grifols: 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; Uniqure: Membership on an entity's Board of Directors or advisory committees; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees; Kedrion: Research Funding.

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Improving Lentiviral Transduction Efficiency with Microfluidic Systems

Blood ◽

10.1182/blood.v126.23.4415.4415 ◽

2015 ◽

Vol 126 (23) ◽

pp. 4415-4415 ◽

Cited By ~ 4

Author(s):

Reginald Tran ◽

David R Myers ◽

Jordan E Shields ◽

Byungwook Ahn ◽

Yongzhi Qiu ◽

...

Keyword(s):

Gene Therapy ◽

Flow Cytometry ◽

Gene Transfer ◽

Hemophilia A ◽

Ex Vivo ◽

Transduction Efficiency ◽

Bottom Surface ◽

Gfp Expression ◽

Cell Numbers ◽

Equity Ownership

Abstract Background: Recent clinical trials have demonstrated the efficacy and safety of gene therapy utilizing HIV-derived lentiviral vectors (LVs) for blood disorders. However, the LV requirements and clinical ex vivo cell transduction protocols used in these studies exposes the limitations of the technology and beckons the need for improved LV manufacturing and clinical transduction efficiency. Many methods have been devised to enhance efficiency, although none have circumvented the exorbitant amounts of virus required to achieve therapeutic HSC transduction. Furthermore, prolonged ex vivo cell culture is necessary to achieve sufficient transduction despite exposure to toxic byproducts of LV production. To that end, we developed a novel, scalable microfluidic for clinical LV transduction that leverages mass transfer principles to significantly reduce the amount of LV required to achieve therapeutic levels of gene transfer and transduction time by more efficiently exposing cells to virus. Results: Jurkats were transduced with a GFP-encoding clinical LV in microfluidics with surface areas (SAs) comparable to the bottom surface of 96 and 6-well plates. Microfluidic transductions were compared to well plate transductions with matched SA, cell numbers, viral particles, and incubation times. After LV incubation, cells were removed from the microfluidics and well plates, spun down, re-suspended with fresh media, and cultured for at least 72 hours at 37°C and 5% CO2. Cells were assessed for GFP expression with flow cytometry. Preliminary mouse studies utilized Sca+ cells isolated from CD45.1 donor mice via positive selection. The cells were transduced in the scaled up microfluidic with a bioengineered coagulation factor VIII (fVIII) transgene encoding LV and transplanted into host hemophilia A mice after myeloablative conditioning. Two weeks post-transplantation, blood samples were taken from the recipient animals and assayed for donor cell engraftment by flow cytometry and plasma fVIII activity by chromogenic assay. The high SA:volume ratio of the microfluidic enhances transduction by physically bringing cells and virus into closer proximity and enabling high concentrations of virus to be used without increasing the amount of virus set by the minimum volume requirements of LV transduction platforms (Fig. 1A). The polystyrene bottom of the microfluidic allows for Retronectin coating that immobilizes non-adherent cells on the bottom surface. LV can then be perfused at low concentrations to maintain a constant supply of fresh virus to the cells, increase convective mixing, and to minimize cell exposure to the toxic byproducts of LV production (Fig. 1B). These microfluidics have been scaled up to accommodate 106 cells, with potential to scale up to 107-108 cells (Fig. 1C). Cells transduced in the microfluidics showed 2-6 fold increases in GFP expression over well plates utilizing the same amount of cells, virus, and incubation times (Fig. 2A). The kinetics of LV transduction in the microfluidics also are faster, as seen by the steeper transduction curve. Five hours of incubation in the microfluidic yielded comparable transduction to 24 hours in the 6-well plate (Fig. 2B). Improvements in transduction also were observed by perfusing virus despite using lower virus concentrations (Fig. 2C). Finally, hemophilia A mice transplanted with donor CD45.1 Sca+ cells transduced in the microfluidic have engrafted (Fig. 3A) and produce fVIII (Fig. 3B) after two weeks with similar profiles to control cells transduced in a 6-well plate despite using half the amount of virus and shorter incubation times. Conclusions and ongoing efforts: We describe a novel microfluidic that significantly reduces the amount of virus and ex vivo processing time required for therapeutic levels of transduction in clinical gene therapy. This device is versatile in its compatibility with current transduction strategies such as Retronectin and polybrene in addition to offering new approaches to boosting gene transfer efficiency. Furthermore, we have shown that the device has clinical potential by successfully scaling up cell numbers and transplanting mice with microfluidic transduced cells, of which there is an ongoing effort to monitor fVIII production and determine virus copy number. Future work will involve optimization with transduction-enhancing compounds, further scaling, and continued in vivo experiments. Disclosures Spencer: Expression Therapeutics: Equity Ownership. Doering:Bayer Healthcare: Consultancy, Honoraria, Research Funding; Expression Therapeutics: Equity Ownership.

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Longitudinal Analysis of Long-Term Safety and Efficacy of Recombinant Factor VIII Fc Fusion Protein (rFVIIFc) in Adults/Adolescents with Severe Hemophilia a

Blood ◽

10.1182/blood.v128.22.1413.1413 ◽

2016 ◽

Vol 128 (22) ◽

pp. 1413-1413

Author(s):

Barbara Konkle ◽

K John Pasi ◽

David J Perry ◽

Johnny Mahlangu ◽

Savita Rangarajan ◽

...

Keyword(s):

Treatment Group ◽

Board Of Directors ◽

Research Funding ◽

Hemophilia A ◽

Severe Hemophilia ◽

Employment Equity ◽

Advisory Committees ◽

Equity Ownership ◽

Dosing Intervals

Abstract Background: Prophylactic replacement of coagulation factor VIII (FVIII) is the standard of care for patients with hemophilia A; however, prophylaxis with conventional FVIII products usually requires frequent intravenous injections (3-4 times/week). The safety, efficacy, and prolonged half-life of rFVIIIFc in previously treated adults and adolescents (≥12 y) with severe hemophilia A were demonstrated in the phase 3 A-LONG study (NCT01181128, completed) and ASPIRE extension study (NCT01454739, ongoing). Here, we report cumulative long-term data on the safety and efficacy of rFVIIIFc in study participants as of the second interim data cut (8 Dec 2014). Methods: This longitudinal analysis includes cumulative data from A-LONG and ASPIRE (as of the second interim data cut 8 Dec 2014) for subjects treated with ≥1 dose of rFVIIIFc. A-LONG evaluated 2 prophylaxis regimens-individualized (IP): 25 IU/kg on Day 1 and 50 IU/kg on Day 4 to start, then 25-65 IU/kg every 3-5 days, to target a 1-3 IU/dL FVIII trough level, and weekly (WP): 65 IU/kg dosed once weekly-as well as episodic (on-demand) treatment (ET). Subjects completing A-LONG and meeting enrollment criteria for ASPIRE could participate in the IP, WP, or ET groups, or, if optimal dosing could not be achieved with IP or WP, in an additional modified prophylaxis (MP) group. Subjects could change treatment groups at any point during ASPIRE. Efficacy analyses were performed using data summarized according to the treatment group in which each subject participated, for the time period they were in that treatment group; thus, subjects may be included in the analysis of more than one group. Outcomes evaluated included: incidence of inhibitors (neutralizing antibody value ≥0.6 BU/mL identified and confirmed on 2 separate samples drawn approximately 2-4 weeks apart and performed by the central laboratory as measured by the Nijmegen-modified Bethesda assay), adverse events (AEs), annualized bleeding rate (ABR), treatment of acute bleeds, and prophylactic consumption and dosing interval compared to pre-A-LONG (prestudy). Results: Of 164 subjects dosed with rFVIIIFc during A-LONG, 153 completed the study and 150 enrolled in ASPIRE; at the time of this second interim data cut, 97 subjects were ongoing in ASPIRE, 40 subjects had completed the study, and 13 subjects withdrew. Cumulatively, subjects had 38,662 rFVIIIFc exposure days (EDs), inclusive of surgery. As of this second interim data cut (8 Dec 2014), no inhibitors were observed; the type and incidence of adverse events (AEs) observed were typical of previous hemophilia A populations studied. There were no reports of anaphylaxis or serious hypersensitivity events, and no serious vascular thrombotic events. Median ABRs for subjects on IP and WP (MP was not an option during A-LONG) were lower with rFVIIIFc compared with prestudy FVIII for subjects on prestudy prophylaxis or ET (Figure). In the IP group, the median (interquartile range [IQR]) spontaneous ABRs in Years 1, 2, and 3 on-study were 0.0 (0.0, 2.0), 0.0 (0.0, 1.0), and 0.0 (0.0, 1.0), respectively. In the WP treatment group, the median (IQR) spontaneous ABRs in Years 1, 2, and 3 on-study were 1.0 (0.5, 3.0), 0.5 (0.0, 2.1), and 0.0 (0.0, 1.0), respectively. Overall, 88.5% and 97.0% of bleeding episodes were controlled with 1 or ≤2 intervenous injections, respectively. Among subjects treated with FVIII prophylaxis prestudy (n = 79), 86% were dosed at least 3 times/week prestudy. Compared with prestudy dosing intervals, dosing intervals with rFVIIIFc were extended in 96.2% of subjects, were shortened in 2.5% of subjects, and were unchanged in 1.3% of subjects. The median (IQR) total weekly prophylactic consumption was comparable (prestudy FVIII: 78.0 [60.0, 102.0] IU/kg; on-study rFVIIIFc: 75.0 [70.0, 113.8] IU/kg). Conclusions: Longitudinal data from patients with severe hemophilia A treated with rFVIIIFc in A-LONG and ASPIRE confirm long-term safety, with no inhibitors observed in any subject. Low median ABRs were maintained, and rFVIIIFc demonstrated efficacy in the prevention and treatment of bleeding episodes. Prophylactic dosing intervals were extended, without an increase in median prophylactic factor consumption. This research was funded by Biogen and Sobi. Biogen and Sobi reviewed and provided feedback on the abstract. The authors had full editorial control of the abstract and provided their final approval of all content. Disclosures Pasi: Biogen: Consultancy, Honoraria; Genzyme: Consultancy, Honoraria; SOBI: Honoraria, Membership on an entity's Board of Directors or advisory committees; Octapharma: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria. Perry:Novo Nordisk: Consultancy, Membership on an entity's Board of Directors or advisory committees; Biogen: Consultancy, Honoraria. Mahlangu:Bayer: Research Funding, Speakers Bureau; CSL: Consultancy, Research Funding, Speakers Bureau; Biotest: Speakers Bureau; Biogen: Consultancy, Research Funding, Speakers Bureau; Novo Nordisk: Consultancy, Research Funding, Speakers Bureau; Amgen: Speakers Bureau; Roche: Consultancy, Research Funding; Baxalta: Consultancy. Rangarajan:Baxter: Research Funding; Baxalta, now part of Shire: Other: Investigator Clinical Studies, Research Funding; Biogen: Consultancy; Biotest: Research Funding; Grifols: Consultancy, Research Funding; Pfizer: Research Funding; Novo Nordisk: Research Funding. Brown:Baxter: Consultancy; Biogen: Consultancy; Novo Nordisk: Consultancy. Hanabusa:Novo Nordisk: Honoraria, Membership on an entity's Board of Directors or advisory committees; Baxalta: Honoraria, Membership on an entity's Board of Directors or advisory committees; KaketsuKen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria; Bayer: Honoraria; Biogen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Pabinger:Biotest: Honoraria, Membership on an entity's Board of Directors or advisory committees; CSL Behring: 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. Cristiano:Biogen: Employment, Equity Ownership. Tsao:Biogen: Employment, Equity Ownership. Winding:Sobi: Employment. Glazebrook:Biogen: Employment, Equity Ownership. Lethagen:Sobi: Employment. Jackson:Biogen: Consultancy, Research Funding; Pfizer: Research Funding; Bayer: Research Funding; Baxalta/Shire: Research Funding; Novo Nordisk: Research Funding; Baxter: Consultancy, Research Funding.

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Long-Term Safety and Efficacy of rFVIIIFc in Adults and Adolescents with Severe Hemophilia A: A Longitudinal Analysis of A-LONG and ASPIRE

Blood ◽

10.1182/blood.v126.23.1087.1087 ◽

2015 ◽

Vol 126 (23) ◽

pp. 1087-1087 ◽

Cited By ~ 3

Author(s):

K John Pasi ◽

David J Perry ◽

Johnny Mahlangu ◽

Barbara A Konkle ◽

Savita Rangarajan ◽

...

Keyword(s):

Treatment Group ◽

Board Of Directors ◽

Research Funding ◽

Hemophilia A ◽

Severe Hemophilia ◽

Employment Equity ◽

Advisory Committees ◽

Treatment Groups ◽

Equity Ownership

Abstract Background: Prophylactic replacement of coagulation factor VIII (FVIII) is the standard of care for patients with hemophilia A; however, prophylactic treatment with conventional FVIII products usually requires frequent intravenous infusions (3-4 times/week). Recombinant FVIII Fc fusion protein (rFVIIIFc), which is produced in a human cell line, binds the neonatal Fc receptor and utilizes the natural IgG recycling pathway to prolong the half-life of FVIII. The safety, efficacy and prolonged half-life of rFVIIIFc in adults and adolescents with severe hemophilia A were demonstrated in the phase 3 A-LONG study (NCT01027377, completed) and ASPIRE extension study (NCT01454739, ongoing). Here, we report cumulative long-term data on the safety and efficacy of rFVIIIFc in participants in these studies. Methods: This longitudinal analysis includes cumulative data from A-LONG and ASPIRE (as of the interim data cut, 6 January 2014) for subjects treated with ≥1 dose of rFVIIIFc (n=164). A-LONG evaluated 2 prophylaxis regimens-individualized (IP): 25 IU/kg on day 1 and 50 IU/kg on day 4 to start, then 25-65 IU/kg every 3-5 days, to target a 1-3 IU/dL FVIII trough level, and weekly (WP): 65 IU/kg dosed once weekly-as well as episodic (on-demand) treatment. Subjects completing A-LONG and meeting enrollment criteria for ASPIRE could participate in the IP, WP, or episodic treatment groups, or, if optimal dosing could not be achieved with IP or WP, in an additional modified prophylaxis (MP) treatment group. Subjects could change treatment groups at any point during ASPIRE. For efficacy analyses, data were summarized according to the treatment group in which each subject participated, for the time period they were in that treatment group; thus, subjects may be included in the analysis of more than one treatment group. Outcomes evaluated included: incidence of inhibitors (neutralizing antibody value ≥0.6 BU/mL as measured by the Nijmegen-modified Bethesda assay at a central laboratory, confirmed upon retesting within 2 to 4 weeks), adverse events (AEs), annualized bleeding rate (ABR), treatment of acute bleeds, and prophylactic dose and dosing interval. Results: Of the 164 subjects dosed with rFVIIIFc during A-LONG, 153 completed the study and 150 enrolled in ASPIRE. At the time of the interim data cut, 140 subjects were ongoing in ASPIRE. Cumulatively, subjects had a median (IQR) of 25.5 (24.6, 26.7) months of rFVIIIFc treatment, and a median (IQR) of 183.0 (120.5, 232.5) rFVIIIFc exposure days (EDs). No inhibitors were reported. The estimated inhibitor incidence rate (95% CI) was 0.0% (0.0, 2.2) overall (N=164), and 0.0% (0.0, 2.7) in subjects with ≥100 rFVIIIFc EDs (n=136). The type and incidence of AEs observed were consistent with those expected for the general hemophilia population. 84.8% of subjects reported ≥1 AE on study, with the majority assessed by the investigator as mild and unrelated to rFVIIIFc treatment. 17.7% of subjects experienced at least 1 SAE; none were assessed by the investigator as related to rFVIIIFc. There were no reports of anaphylaxis or serious hypersensitivity events, and no serious vascular thrombotic events. Median ABRs for subjects on IP and WP (MP was not an option during A-LONG) were generally lower with rFVIIIFc treatment compared with prestudy FVIII (Figure). In the IP treatment group, the year 1 and year 2 median spontaneous ABRs were 0.0. Overall, 89.1% of bleeding episodes were controlled with 1 infusion; 97.3% with 1 or 2 infusions. Among subjects treated with FVIII prophylaxis prior to entering A-LONG (n=79), 86% were dosed at least 3 times/week. With rFVIIIFc, 96% of these subjects extended their dosing interval compared with their prestudy product, while the median (IQR) total weekly prophylactic dose was comparable (prestudy FVIII: 78.0 [60.0, 102.0] IU/kg; on-study rFVIIIFc: 75.0 [70.0, 113.2] IU/kg). Conclusions: Longitudinal data from patients with severe hemophilia A treated with rFVIIIFc in A-LONG and ASPIRE demonstrate long-term safety, with no inhibitors observed in any subjects, and efficacy in the prevention and treatment of bleeding. Low median ABRs were maintained with extended prophylactic dosing intervals, without an increase in median prophylactic factor consumption. Figure 1. Figure 1. Disclosures Pasi: Biogen, Octapharma, Genzyme, and Pfizer: Consultancy, Honoraria; Octapharma: Research Funding. Perry:Novo Nordisk: Consultancy, Membership on an entity's Board of Directors or advisory committees; Biogen: Consultancy, Honoraria. Mahlangu:Roche: Research Funding; Biotest: Speakers Bureau; Bayer, CSL, Novo Nordisk, and Biogen: Research Funding, Speakers Bureau; Amgen: Speakers Bureau. Konkle:Baxalta: Consultancy, Research Funding; Biogen: Consultancy, Research Funding; CSL Behring: Consultancy, Other: IDMC chair; Pfizer: Other: IDMC member; Octapharma: Research Funding; Novo Nordisk: Consultancy. Rangarajan:Grifols, Pfizer, and Baxter: Research Funding; Grifols: Honoraria; Sobi: Membership on an entity's Board of Directors or advisory committees; LFB: Other: Conference support. Brown:Biogen, Novo Nordisk, Baxter, and Pfizer: Other: Sponsorship to meeting. Hanabusa:Novo Nordisk, Baxalta, Bayer, Pfizer, Biogen, and KaketsuKen: Honoraria; Novo Nordisk, Baxalta, KaketsuKen, and Biogen: Membership on an entity's Board of Directors or advisory committees. Jackson:Biogen: Honoraria, Speakers Bureau; Baxalta: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Bayer: Membership on an entity's Board of Directors or advisory committees; Novo Nordisk: Membership on an entity's Board of Directors or advisory committees. Cristiano:Biogen: Employment, Equity Ownership. Dong:Biogen: Employment, Equity Ownership. Tsao:Biogen: Employment, Equity Ownership. Pierce:Biogen: Equity Ownership, Other: Former employee. Allen:Biogen: Employment, Equity Ownership.

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Sustained Phenotypic Correction of Murine Hemophilia A with Pre-Existing Anti-FVIII Immunity Using Lentivirus-Mediated Platelet-Specific FVIII Gene Transfer.

Blood ◽

10.1182/blood.v114.22.29.29 ◽

2009 ◽

Vol 114 (22) ◽

pp. 29-29 ◽

Cited By ~ 1

Author(s):

Qizhen Shi ◽

Erin L. Kuether ◽

Brian C. Cooley ◽

Scot A. Fahs ◽

Jocelyn A. Schroeder ◽

...

Keyword(s):

Stem Cells ◽

Gene Therapy ◽

Bone Marrow ◽

Gene Transfer ◽

Real Time Pcr ◽

Hemophilia A ◽

Hematopoietic Stem ◽

Fviii Activity ◽

Inhibitory Antibodies ◽

Tail Clip

Abstract Abstract 29 The development of inhibitory antibodies to exogenous factor VIII (FVIII) is considered a severe and important complication of FVIII infusion in hemophilia A patients. Gene therapy of hemophilia A with inhibitors is especially challenging because functional FVIII activity may be inactivated by circulating inhibitory antibodies if transgene protein is constitutively secreted into the blood circulation. Our previous studies have demonstrated that syngeneic transplantation of hematopoietic stem cells from 2bF8 transgenic mice that express platelet-specific FVIII can efficiently restore hemostasis to hemophilic mice with pre-existing inhibitory antibodies. In the current study, we assessed whether lentivirus-mediated 2bF8 gene transfer could efficiently introduce 2bF8 transgene expression and ameliorate the hemorrhagic phenotype in hemophilic mice with pre-existing immunity. To mimic the clinical situation of an autologous transplant in an inhibitor patient, both donor and recipient FVIIInull mice were immunized with recombinant human B-domain deleted FVIII to induce inhibitory antibody development. Platelet-derived FVIII expression in FVIIInull mice was introduced by 2bF8 lentiviral-mediated bone marrow (BM) transduction and syngeneic transplantation. Following BM reconstitution, mice were analyzed by PCR, quantitative real-time PCR, platelet lysate FVIII activity assay, and inhibitor assay. Phenotypic correction was assessed by tail clip survival test and electrolytic-induced thrombus formation. Expression of the 2bF8 product was detected in all recipients that received 2bF8 lentivirus transduced BM cells, indicating viable engraftment of BM genetically modified with the 2bF8 lentivirus transfer vector. Functional platelet-FVIII activity levels in the transduced mice with pre-existing immunity ranged from 0.36 to 6.18 mU/108 platelets (mean 1.56 ± 1.76 mU/108 platelets, n = 10), which was not significantly different from the levels obtained from a parallel non-inhibitor model (1.46 ± 0.87 mU/108 platelets, n = 4). Real-time PCR demonstrated that there was an average of 0.17 ± 0.05 LV DNA copies per cell in peripheral white blood cells from transduced mice. FVIII inhibiter titer gradually declined with the time, indicating that transduced platelet FVIII is well protected from exposure to the immune system, avoiding activation of a memory response. The tail clip survival test showed that 90% of mice survived tail clip challenge. The electrolytic injury model demonstrated that hemostasis was improved in recipients that received 2bF8 lentivirus-transduced BM cells. Furthermore, BM transferred from the primary transplant recipients into immunized FVIIInull secondary recipients demonstrated sustained platelet-FVIII expression, resulting in the correction of the hemophilia A phenotype with pre-existing immunity. This shows that gene transfer has occurred within long-term repopulating hematopoietic stem cells even in the presence of inhibitory antibodies. These results demonstrate that lentivirus-mediated bone marrow transduction/transplantation can provide sustained improvement of hemostasis in hemophilic mice with pre-existing immunity, indicating that this approach may be a promising strategy for gene therapy of hemophilia A with inhibitory antibodies in humans. Disclosures: Montgomery: GTI Diagnostics: Consultancy; Baxter: Consultancy; AstraZeneca: Consultancy; Bayer: Research Funding; CSL Behring: Membership on an entity's Board of Directors or advisory committees.

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Dosing Long-Lasting Recombinant Factor VIII Fc Fusion Protein: Experience In The A-LONG Study

Blood ◽

10.1182/blood.v122.21.3598.3598 ◽

2013 ◽

Vol 122 (21) ◽

pp. 3598-3598 ◽

Cited By ~ 1

Author(s):

Amy Shapiro ◽

Margaret V. Ragni ◽

Roshni Kulkarni ◽

Sarah Kulke ◽

James Potts ◽

...

Keyword(s):

Board Of Directors ◽

Research Funding ◽

Hemophilia A ◽

Dose Interval ◽

Severe Hemophilia ◽

Prophylactic Regimen ◽

Advisory Committees ◽

Population Pk ◽

Dosing Regimens ◽

Equity Ownership

Abstract Introduction Prophylaxis with factor VIII (FVIII) in patients with severe hemophilia A requires frequent intravenous injections (3–4 per week), impacting compliance and outcomes. A long-lasting recombinant FVIII Fc fusion protein (rFVIIIFc) was developed to reduce the frequency of injections. The pharmacokinetics (PK), safety, and efficacy of rFVIIIFc were evaluated in the phase 3 A-LONG study and the primary results were reported recently (Mahlangu J, J Thromb Haemost 2013). To illustrate differences in dosing regimens and clinical outcomes with rFVIIIFc and currently available FVIII products, we compared the prestudy and on-study dose, dose interval, and bleeding rates for subjects in A-LONG who reported receiving a prophylactic regimen with any FVIII product prior to study entry. We also used population PK models to estimate trough FVIII levels on various dosing regimens of rFVIIIFc and rFVIII (Advate®). Methods Previously treated male patients who were ≥12 years old with severe hemophilia A were enrolled in A-LONG and assigned to 1 of 3 treatment arms: Arm 1, individualized prophylaxis with PK-driven dose and dose interval adjustments (25–65 IU/kg every 3–5 days); Arm 2, once weekly prophylaxis (65 IU/kg); and Arm 3, episodic treatment (10–50 IU/kg) for bleeding episodes. A 2-compartmental population PK model of rFVIIIFc was developed based on activity-time profiles in 180 severe hemophilia A subjects aged 12-65 years old (16 from a phase 1/2a study and 164 from A-LONG collected over ≤ 52 weeks of treatment). A 2-compartment population PK model of Advate® was developed based on the single-dose PK profiles from 16 subjects in the phase 1/2a study and 30 subjects in the sequential PK subgroup in A-LONG. The population PK estimates for Advate® and rFVIIIFc from A-LONG were used for dosing simulations. We identified Arm 1 subjects who reported use of a prophylactic regimen at least 2 times a week with any FVIII product prior to study entry and compared their dosing regimens and bleeding rate in the 12 months prior to study with their rFVIIIFc dosing regimens and annualized bleed rate (ABR) on study. Only subjects on study for ≥ 6 months were included. The median ABR, dose, and dose interval during the last 3 months on study were analyzed. Results Of 165 total patients, 118 were in Arm 1, of whom 80 received a prophylactic regimen at least 2 times a week prestudy and were in the study for ≥ 6 months. Subjects were grouped by prestudy dosing interval. The table below provides prestudy and on study dose, dose interval, and bleeding rates for these groups. The majority of patients (65/80) reported a dosing interval of 3 times a week, with the most common dose of 25 IU/kg FVIII, and a median of 5.5 bleeding events 12 months prior to study entry. At the end of the study, these same patients were receiving ∼40 IU/kg rFVIIIFc twice a week (every 3.5 days) with a median ABR of 0. Population PK simulation indicated that 76.1% of patients treated with 40 IU/kg of rFVIIIFc twice a week would maintain FVIII levels above 1% at all times. In contrast, population PK simulation indicated that 42.3% of patients treated with 25 IU/kg of Advate® 3 times a week would maintain FVIII levels above 1% at all times. Overall, rFVIIIFc was well tolerated and no inhibitor development was detected during the A-LONG study. Conclusion The results from this descriptive analysis of dose, dose interval, and bleeding rates for subjects with severe hemophilia A who were on prophylaxis suggest that switching from current FVIII products to a rFVIIIFc regimen may allow for less frequent dosing to maintain FVIII activity >1%. Disclosures: Shapiro: Baxter: Consultancy, Global steering committees Other, Membership on an entity’s Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novo Nordisk: Consultancy, Membership on an entity’s Board of Directors or advisory committees, Research Funding, Speakers Bureau; Bayer: Global steering committees, Global steering committees Other, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Inspiration: Consultancy, Membership on an entity’s Board of Directors or advisory committees, Research Funding; CSL Behring: Research Funding; Biogen Idec: Research Funding. Ragni:Biogen Idec: Membership on an entity’s Board of Directors or advisory committees, Research Funding; Bristol Myers Squibb: Consultancy, Research Funding; Smith Kline Glaxo: Consultancy, Research Funding; Tacere Benitec: Consultancy; Baxter: Research Funding; Bayer: Research Funding; CSL Behring: Research Funding; Merck: Research Funding; Novo Nordisk: Research Funding; Pfizer: Research Funding. Kulkarni:Biogen Idec, Novo Nordisk, Baxter : Membership on an entity’s Board of Directors or advisory committees. Kulke:Biogen Idec: Employment. Potts:Biogen Idec: Employment. Neelakantan:Biogen Idec: Employment. Nestorov:Biogen Idec: Employment. Dumont:Biogen Idec: Employment; Biogen Idec: Equity Ownership. Jiang:Biogen Idec: Employment; Biogen Idec: Equity Ownership. Brennan:Biogen Idec: Employment; Biogen Idec: Equity Ownership. Pierce:Biogen Idec: Employment, Equity Ownership.

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Fitusiran, an Investigational RNAi Therapeutic Targeting Antithrombin for the Treatment of Hemophilia: Updated Results from a Phase 1 and Phase 1/2 Extension Study in Patients with Inhibitors

Blood ◽

10.1182/blood.v128.22.1397.1397 ◽

2016 ◽

Vol 128 (22) ◽

pp. 1397-1397 ◽

Cited By ~ 9

Author(s):

K John Pasi ◽

Pencho Georgiev ◽

Tim Mant ◽

Toshko Lissitchkov ◽

Michael Desmond Creagh ◽

...

Keyword(s):

Board Of Directors ◽

Research Funding ◽

Thrombin Generation ◽

Hemophilia A ◽

Phase 1 ◽

Extension Study ◽

Severe Hemophilia ◽

Employment Equity ◽

Advisory Committees ◽

Equity Ownership

Abstract Background: Development of inhibitory antibodies, also known as "inhibitors," to replacement factor is considered the most serious unmet need in hemophilia and occurs in up to 30% of persons with severe hemophilia A, and 3-5% of persons with severe hemophilia B. Once inhibitors are present in high titer, treatment or prevention of bleeding can become more difficult due to the decreased responsiveness to factor concentrates, requiring bypassing agents (BPA) for bleed management. Current BPAs have a short half-life and are sub-optimally effective. Fitusiran is a subcutaneously (SC) administered investigational RNA interference (RNAi) therapeutic targeting the endogenous anticoagulant antithrombin (AT) as a means to improve thrombin generation and promote hemostasis in patients with hemophilia. Preliminary data from an ongoing Phase 1, multi-center, study showed that fitusiran was generally well tolerated in patients with hemophilia A or B with and without inhibitors and that administration of once-monthly SC doses of fitusiran led to dose-dependent AT lowering, thrombin generation increase, and decrease in bleeding frequency (Pasi KJ, et al. Haemophilia 2016, 22[Suppl 4]). Here we report the updated safety, pharmacodynamic (PD) effect, and clinical activity of fitusiran in patients with hemophilia with inhibitors as well as long term data from the Phase 1/2 extension study. Methods: We are conducting a multi-center Phase 1, four part (Part A: healthy volunteers; Parts B and C: patients with moderate to severe hemophilia A or B; Part D: patients with hemophilia A or B with inhibitors) study (NCT02035605) followed by a multi-center Phase 1/2 extension study (NCT02554773). Primary endpoints include safety and tolerability; secondary endpoints include AT activity, thrombin generation and exploratory evaluation of bleed pattern. In Part D, patients with inhibitors received once-monthly SC fixed doses of 50 or 80mg fitusiran. After receiving 3 monthly doses in the Phase 1 study, all patients were eligible to continue monthly dosing in the Phase 1/2 extension study. Utilization of BPA for breakthrough bleed management was permissible in these patients. Results: Part D of the Phase 1 study included 12 hemophilia A or B patients with inhibitors in 2 dosing cohorts (50mg SC, qM dosing cohort, n=6; 80mg SC, qM dosing cohort, n=6). Within the 50mg dosing cohort there were five patients with severe hemophilia A with inhibitors and one patient with severe hemophilia B with inhibitors; mean age: 33 ± 7 years; mean weight: 73 ± 17kg. Previously reported safety data from the 50mg dosing cohort demonstrated fitusiran was generally well tolerated in hemophilia A or B patients with inhibitors and that there were no serious adverse events related to study drug and no thromboembolic events. Monthly administration of fitusiran at the 50mg dose led to a mean maximal AT lowering of 81 ± 2% and mean maximal thrombin generation increase of 368 ± 113%. A preliminary, post-hoc analysis suggested a 49-100% reduction in bleeding frequency at the lower dose of 50mg during initial follow-up in the Phase 1 study. As of July 2016, the 80mg dose cohort has been fully enrolled and includes 6 patients with hemophilia A with inhibitors; mean age: 39 ± 15 years; mean weight: 75 ± 19kg, and 5 of the 6 patients in the initial 50mg cohort have transitioned to the Phase 1/2 extension study. Follow-up in the Phase 1, 80mg cohort and Phase 1/2 extension study is ongoing. Updated safety, tolerability and clinical activity from the Phase 1 and Phase 1/2 extension studies among all 12 patients with inhibitors will be presented. Conclusions: Emerging clinical data suggest that targeting AT is generally safe and could be a promising approach for promoting hemostasis in patients with hemophilia with inhibitors. Furthermore, the potential for low volume SC administration, monthly dosing, and applicability to patients with hemophilia A and B with and without inhibitors make fitusiran a potentially encouraging investigational therapy. Disclosures Pasi: Biogen: Consultancy, Honoraria; Octapharma: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria; Genzyme: Consultancy, Honoraria; SOBI: Honoraria, Membership on an entity's Board of Directors or advisory committees. Georgiev:Alnylam Pharmaceuticals: Consultancy. Chowdary:Bayer: Honoraria; Baxalta: 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, Research Funding; Sobi: Honoraria; Biogen: Honoraria, Membership on an entity's Board of Directors or advisory committees; CSL Behring: 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. Ragni:Novo Nordisk: Research Funding; Biomarin: Consultancy; Biogen: Consultancy, Research Funding; Alnylam Pharmaceuticals: Consultancy, Research Funding; Genentech: Research Funding; SPARK: Research Funding; Baxalta: Research Funding; CSL Behring: Research Funding; Shire: Consultancy; Vascular Medicine Institute: Research Funding; Tacere Benitec: Consultancy; OPKO: Research Funding. Soh:Alnylam Pharmaceuticals: Employment, Equity Ownership. Akinc:Alnylam Pharmaceuticals: Employment, Equity Ownership. Partisano:Alnylam: Employment, Equity Ownership. Sorenson:Alnylam Pharmaceuticals: Employment, Equity Ownership.

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