Search

Background: Acquired hemophilia A (AHA) is an autoimmune bleeding disorder caused by neutralizing antibodies against coagulation factor VIII. Immunosuppressive therapy (IST) is standard of care to eradicate autoantibody production and protect from further bleeding but carries a risk of severe infection and mortality in frail patients with AHA. Recently, emicizumab has been studied for its potential to reduce the need for early and aggressive IST., Objectives: To compare outcomes of 2 studies that used either IST (GTH-AH 01/2010; N = 101) or prophylaxis with emicizumab (GTH-AHA-EMI; N = 47) early after diagnosis of AHA., Methods: Baseline characteristics were balanced by propensity score matching. Primary endpoint was the rate of clinically relevant new bleeds during the first 12 weeks; secondary endpoints were adverse events and overall survival., Results: The negative binominal model-based bleeding rate was 68% lower with emicizumab as compared with IST (incident rate ratio, 0.325; 95% CI, 0.182-0.581). No difference was apparent in the overall frequency of infections (emicizumab 21%, IST 29%) during the first 12 weeks, but infections were less often fatal in emicizumab-treated patients (0%) compared with IST-treated patients (11%). Thromboembolic events occurred less often with emicizumab (2%) than with IST (7%). Overall survival after 24 weeks was better with emicizumab (90% vs 76%; hazard ratio, 0.44; 95%, CI, 0.24-0.81)., Conclusion: Using emicizumab instead of IST in the early phase after initial diagnosis of AHA reduced bleeding and fatal infections and improved overall survival., Competing Interests: Declaration of competing interests C.H. reports honoraria for lectures or consultancy from Bayer, BMS, SOBI, Daiichi Sankyo, Roche/Chugai, Pfizer, Sanofi, and Takeda. R.K. reports institutional grants for research and studies from Bayer, CSL Behring, Novo Nordisk, Octapharma, and SOBI, and honoraria for lectures or consultancy from Bayer, Biotest, BioMarin, CSL Behring, Grifols, LFB, Novo Nordisk, Octapharma, Pfizer, Roche/Chugai, Sanofi, SOBI, and Takeda. U.J.S. reports institutional grants for research and studies from Octapharma and honoraria for lectures or consultancy from Bayer, SOBI, CSL Behring, and Pfizer. R.G. reports institutional grants for research and studies from Celgene, Roche, Merck, Takeda, AstraZeneca, Novartis, Amgen, BMS, MSD, Sandoz, Abbvie, Gilead, and Daiichi Sankyo, and honoraria for lectures or consultancy from Celgene, Roche, Merck, Takeda, AstraZeneca, Novartis, Amgen, BMS, MSD, Sandoz, Abbvie, Gilead, Daiichi Sankyo, and Sanofi. P.K. reports institutional grants for research and studies from Ablynx/Sanofi, Novo Nordisk, Roche, and Takeda, and honoraria for lectures or consultancy from Ablynx/Sanofi, Alexion, Biotest, CSL Behring, Novo Nordisk, Roche, Takeda, and Technoclone. J.O. reports institutional grants for research and studies from Bayer, Biotest, CSL Behring, Octapharma, Pfizer, SOBI, and Takeda, and honoraria for lectures or consultancy from Bayer, Biogen Idec, BioMarin, Biotest, CSL Behring, Chugai, Freeline, Grifols, Novo Nordisk, Octapharma, Pfizer, Roche, Sparks, SOBI, and Takeda. W.M. reports institutional grants for research and studies from Bayer, Biotest, CSL Behring, LFB, Novo Nordisk, Octapharma, Pfizer, and Takeda/Shire, and honoraria for lectures or consultancy from Bayer, BioMarin, Biotest, CSL Behring, Chugai, Freeline, LFB, Novo Nordisk, Octapharma, Pfizer, Regeneron, Roche, Sanofi, Takeda/Shire, and uniQure. C.P. reports institutional grants for research and studies from Chugai/Roche, Takeda, Zacros, and LeoPharma, and honoraria for lectures or consultancy from Bayer, BioMarin, Chugai/Roche, CSL Behring, Novo Nordisk, Pfizer, BMS, SOBI, and Takeda. K.T.G. reports honoraria for lectures or consultancy from Takeda, Roche, Grifols, and SOBI. I.P. reports institutional grants for research and studies from Takeda and honoraria for lectures or consultancy from BMS and Novo Nordisk. K.H. reports institutional grants for research and studies from Bayer, CSL Behring, Novo Nordisk, Pfizer, and SOBI, and honoraria for lectures or consultancy from Bayer, Biotest, Chugai, CSL Behring, LFB, Novo Nordisk, Pfizer, Roche, SOBI, and Takeda. H.E. reports institutional grants for research and studies from Bayer Vital and CSL Behring and honoraria for lectures or consultancy from Bayer Vital, BioMarin, CSL Behring, Novo Nordisk, Pfizer, Roche, and SOBI. C.W. has nothing to disclose. D.S. has nothing to disclose. S.W. reports institutional grants for research and studies from Biotest and Octapharma, and honoraria for lectures or consultancy from Biotest and Stago. A.T. reports institutional grants for research and studies from Bayer, Biotest, Chugai, Novo Nordisk, Octapharma, Pfizer, Roche, SOBI, and Takeda, and honoraria for lectures or consultancy from Bayer, BioMarin, Biotest, Chugai, CSL Behring, Novo Nordisk, Octapharma, Pfizer, Roche, SOBI, and Takeda., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Acquired hemophilia A (AHA) is a severe bleeding disorder caused by inhibiting autoantibodies to coagulation factor VIII (FVIII). For hemostatic treatment, bypassing agents and human or porcine FVIII are currently standard of care. Emicizumab is a bispecific, FVIII-mimetic therapeutic antibody that reduced the annualized bleeding rates in congenital hemophiliacs. Here, we report on 6 male and 6 female patients with AHA treated with emicizumab (all data medians and interquartile range), age 74 (64-80) years, initial FVIII <1%; inhibitor titer 22.3 Bethesda units (BU)/mL (range, 3-2000). Eight patients had severe bleeding. Emicizumab was started, 3 mg/kg subcutaneously, weekly for 2 to 3 doses, followed by 1.5 mg/kg every 3 weeks to keep the lowest effective FVIII levels. For FVIII monitoring, chromogenic assays with human and bovine reagents were used. All patients received immunosuppression with steroids and/or rituximab. After the first dose of emicizumab, activated partial thromboplastin time normalized in 1 to 3 days, FVIII (human reagents) exceeded 10% after 11 (7.5-12) days. Hemostatic efficacy was obtained and bypassing therapy stopped after 1.5 (1-4) days. FVIII (bovine reagents) exceeded 50%, indicating complete remission after 115 (67-185) days, and emicizumab was stopped after 31 (15-79) days. A median of 5 injections (range, 3-9) were given. No patient died of bleeding or thromboembolism, and no breakthrough bleeding was observed after the first dose of emicizumab. In conclusion, emicizumab seems to be an effective hemostatic therapy for AHA, with the advantages of subcutaneous therapy, good hemostatic efficacy, early discharge, and reduction of immunosuppression and adverse events., (© 2021 by The American Society of Hematology.)

Hemophilia A, characterized by absent or ineffective coagulation factor VIII (FVIII), is a serious bleeding disorder that entails severe and potentially life-threatening bleeding events. Current standard therapy still involves replacement of FVIII, but is often complicated by the occurrence of neutralizing alloantibodies (inhibitors). Management of patients with inhibitors is challenging and necessitates immune tolerance induction for inhibitor eradication and the use of bypassing agents (activated prothrombin complex concentrates or recombinant activated factor VII), which are expensive and not always effective. Emicizumab is the first humanized bispecific monoclonal therapeutic antibody designed to replace the hemostatic function of activated FVIII by bridging activated factor IX and factor X (FX) to activate FX and allow the coagulation cascade to continue. In the majority of hemophilic patients with and without inhibitors, emicizumab reduced the annualized bleeding rate to almost zero in several clinical trials and demonstrated a good safety profile. However, the concurrent use of emicizumab and activated prothrombin complex concentrate imposes a high risk of thrombotic microangiopathy and thromboembolic events on patients and should be avoided. Yet, the management of breakthrough bleeds and surgery remains challenging with only limited evidence-based recommendations being available. This review summarizes published clinical trials and preliminary reports of emicizumab and discusses the clinical implications of emicizumab in treatment of hemophilia A., Competing Interests: B.J. reports grants and personal fees from Roche, during the conduct of the study. P.K. reports personal fees from Roche, during the conduct of the study; grants, personal fees, and nonfinancial support from Baxalta/Shire/Takeda; grants, personal fees, and nonfinancial support from Novo Nordisk; grants, personal fees, and nonfinancial support from CSL Behring; grants, personal fees, and nonfinancial support from Ablynx/Sanofi; and grants from Biotest, outside the submitted work., (Thieme. All rights reserved.)

Introduction: Concizumab enhances thrombin generation (TG) potential in haemophilia patients by inhibiting tissue factor pathway inhibitor (TFPI). In EXPLORER3 (phase 1b), a dose-dependent pharmacokinetic/pharmacodynamic (PK/PD) relationship was confirmed between concizumab dose, free TFPI and TG potential., Aim: Determine the association between concizumab exposure, PD markers (free TFPI; peak TG) and bleeding episodes to establish the minimum concizumab concentration for achieving sufficient efficacy., Methods: Free TFPI predictions were generated using an estimated concizumab-free TFPI exposure-response (E max ) model based on concizumab phase 1/1b data for which simultaneously collected concizumab and free TFPI samples were available. Concizumab concentration at the time of a bleed was predicted using a PK model, based on available data for concizumab doses >50 μg/kg to ≤9 mg/kg. Peak TG vs concizumab concentration analyses and an E max model were constructed based on EXPLORER3 observations., Results: The E max model showed a tight PK/PD relationship between concizumab exposure and free TFPI; free TFPI decreased with increasing concizumab concentration. A strong correlation between concizumab concentration and peak TG was observed; concizumab >100 ng/mL re-established TG potential to within the normal reference range. Estimated EC 50 values for the identified concizumab-free TFPI and concizumab-TG potential models were very similar, supporting free TFPI as an important biomarker. A correlation between bleeding episode frequency and concizumab concentration was indicated; patients with a concizumab concentration >100 ng/mL experienced less frequent bleeding. The PK model predicted that once-daily dosing would minimize within-patient concizumab PK variability., Conclusion: Concizumab phase 2 trials will target an exposure ≥100 ng/mL, with a once-daily regimen., (© 2018 The Authors. Haemophilia Published by John Wiley & Sons Ltd.)

Essentials explorer™3 was a double-blinded, multiple-dose escalation trial of subcutaneous concizumab. A pharmacodynamic relationship for unbound TFPI and thrombin generation was confirmed. No serious adverse events and no anti-drug antibodies were observed. explorer™3 data support further clinical development of concizumab in people with hemophilia. SUMMARY: Background Concizumab is a humanized mAb targeting tissue factor pathway inhibitor (TFPI), leading to enhanced thrombin generation (TG) potential. explorer™3 (NCT02490787) was a phase 1b, double-blind, multiple-dose escalation trial of subcutaneous concizumab in people with severe hemophilia A without inhibitors. Objectives The primary objective was to evaluate safety. Assessments of pharmacokinetics, pharmacodynamics and subcutaneous concizumab immunogenicity were secondary objectives. Patients/Methods Adverse events (AEs), clinical assessments and bleeding episodes were recorded. Plasma concizumab levels and unbound TFPI levels were measured with ELISAs; residual TFPI activity was measured with a chromogenic assay. Standardized assays were used to assess TG, D-dimer and prothrombin fragment 1 + 2 (F 1 + 2 ) levels. explorer™3 was completed after investigation of three dose cohorts (0.25, 0.5 and 0.8 mg kg -1 , once every 4 days) had been completed. Twenty-four patients received 12 doses of concizumab or placebo in a 3 : 1 randomization over a 42-day period. Results No serious AEs and no anti-drug antibodies were observed. Fifty-four mild and two moderate AEs were observed in 19 patients. Concizumab exposure increased with dose in a non-linear manner, confirming target-mediated drug disposition. D-dimer and F 1 + 2 levels were increased mostly in the highest dose cohort, in line with previous observations. The level of unbound TFPI decreased in a dose-dependent manner, and was accompanied by a residual TFPI activity decrease and an increase in peak TG. Although the trial was not powered to evaluate efficacy, a trend towards lower bleeding rates was observed in patients in the highest dose cohort. Conclusion explorer™3 data support further clinical development of concizumab for use in people with hemophilia, with or without inhibitors., (© 2018 The Authors. Journal of Thrombosis and Haemostasis published by Wiley Periodicals, Inc. on behalf of International Society on Thrombosis and Haemostasis.)

Background: Prophylaxis with either intravenous (i.v.) factor VIII (FVIII) or FIX is the gold standard of care for patients with severe hemophilia. A monoclonal antibody (concizumab) targeting tissue factor pathway inhibitor (TFPI) that can be administered subcutaneously (s.c.) has the potential to alter current concepts of prophylaxis in hemophilia., Objectives: To evaluate the safety and describe the pharmacokinetics and pharmacodynamics of single-dose concizumab in healthy volunteers and patients with hemophilia A or B., Methods: In this first human dose, phase 1, multicenter, randomized, double-blind, placebo-controlled trial escalating single i.v. (0.5-9000 μg kg(-1) ) or s.c. (50-3000 μg kg(-1) ) doses of concizumab were administered to healthy volunteers (n = 28) and hemophilia patients (n = 24)., Results: Concizumab had a favorable safety profile after single i.v. or s.c. administration. There were no serious adverse events and no anti-concizumab antibodies. No clinically relevant changes in platelets, prothrombin time, activated partial thromboplastin time, fibrinogen, or antithrombin were found. A dose-dependent procoagulant effect of concizumab was seen as increased levels of D-dimers and prothrombin fragment 1 + 2. Nonlinear pharmacokinetics of concizumab was observed due to target-mediated clearance. A maximum mean AUC0-∞ of 33 960 h μg mL(-1) and a maximum mean concentration of 247 μg mL(-1) was measured at the highest dose., Conclusions: Concizumab showed a favorable safety profile after i.v. or s.c. administration and nonlinear pharmacokinetics was observed due to target-mediated clearance. A concentration-dependent procoagulant effect of concizumab was observed, supporting further study into the potential use of s.c. concizumab for hemophilia treatment., (© 2015 The Authors. Journal of Thrombosis and Haemostasis published by Wiley Periodicals, Inc. on behalf of International Society on Thrombosis and Haemostasis.)