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Robert Klamroth,1 Piotr Wojciechowski,2 Samuel Aballéa,3 Françoise Diamand,4 Zalmai Hakimi,5 Jameel Nazir,5 Lydia Abad-Franch,6 Stefan Lethagen,7 Elena Santagostino,8 Michael D Tarantino9 1Department of Internal Medicine, Hemophilia Treatment Centre, Vivantes Klinikum im Friedrichshain, Berlin, Germany; 2Creativ-Ceutical, Krakow, Poland; 3Creativ-Ceutical, Rotterdam, the Netherlands; 4Creativ-Ceutical, Paris, France; 5Health Economics and Outcomes Research (Global), Sobi, Stockholm, Sweden; 6Global Medical Affairs Hematology, Sobi, Stockholm, Sweden; 7Medical and Clinical Sciences, Sobi, Stockholm, Sweden; 8Medical Affairs Hematology, Sobi, Stockholm, Sweden; 9The Bleeding and Clotting Disorders Institute, University of Illinois College of Medicine-Peoria, Peoria, IL, USACorrespondence: Robert KlamrothDepartment of Internal Medicine – Angiology and Hemostaseology, Center for Vascular Medicine, Hämophiliezentrum/Gerinnungssprechstunde, Vivantes Klinikum im Friedrichshain, Landsberger Allee 49, D, Berlin, 10249, Germany, Tel +49 (0)30 130 231575Fax +49 (0)30 130 231313Email robert.klamroth@vivantes.dePurpose: Primary prophylaxis, using factor VIII replacement, is the recognized standard of care for severe hemophilia A. Recombinant factor VIII-Fc fusion protein (rFVIIIFc) and emicizumab, a humanized, bispecific antibody, are approved for routine prophylaxis of bleeding episodes in severe hemophilia A. These products have different mechanisms of action, methods of administration and treatment schedules. In the absence of head-to-head trials, indirect treatment comparisons can provide informative evidence on the relative efficacy of the two treatments. The aim of the study was to compare the approved dosing regimens for each product, rFVIIIFc individualized prophylaxis and emicizumab administered once every week (Q1W), every 2 weeks (Q2W) or every 4 weeks (Q4W), based on clinical trial evidence.Patients and Methods: The comparison was conducted using matching-adjusted indirect comparison since clinical evidence did not form a connected network. Individual patient data for rFVIIIFc (A-LONG) were compared with data for emicizumab (HAVEN trial program) for mean annualized bleeding rate (ABR) and proportion of patients with zero bleeds. Safety data reported across the analyzed treatment arms were tabularized but not formally compared.Results: After matching, no significant differences were observed between mean ABR for rFVIIIFc and emicizumab administered Q1W, Q2W or Q4W. The proportion of patients with zero bleeds was significantly higher with rFVIIIFc compared with emicizumab administered Q4W (51.2% versus 29.3%, respectively; odds ratio 2.53; 95% confidence interval 1.09– 5.89); no significant differences noted when rFVIIIFc was compared with emicizumab administered Q1W or Q2W. The mean number of adverse events expressed per participant was 1.9 for individualized prophylaxis with rFVIIIFc and 3.7– 4.0, 4.1 and 3.6 for emicizumab administered Q1W, Q2W or Q4W, respectively.Conclusion: This indirect treatment comparison suggests that rFVIIIFc individualized prophylaxis is more efficacious than emicizumab Q4W, and at least as effective as more frequent emicizumab regimens, for the management of hemophilia A.Keywords: annualized bleeding rate, antibodies, bispecific, comparative effectiveness research, efmoroctocog alfa, factor VIII deficiency, treatment outcome

Preventing factor VIII (FVIII) inhibitors following replacement therapies with FVIII products in patients with hemophilia A remains an unmet medical need. Better understanding of the early events of evolving FVIII inhibitors is essential for risk identification and the design of novel strategies to prevent inhibitor development. The Hemophilia Inhibitor Previously Untreated Patients (PUPs) Study (HIPS; www.clinicaltrials.gov #NCT01652027) is the first prospective cohort study to evaluate comprehensive changes in the immune system during the first 50 exposure days (EDs) to FVIII in patients with severe hemophilia A. HIPS participants were enrolled prior to their first exposure to FVIII or blood products (“true PUPs”) and were evaluated for different immunological and clinical parameters at specified time points during their first 50 EDs to a single source of recombinant FVIII. Longitudinal antibody data resulting from this study indicate that there are 4 subgroups of patients expressing distinct signatures of FVIII-binding antibodies. Subgroup 1 did not develop any detectable FVIII-binding immunoglobulin G (IgG) antibodies. Subgroup 2 developed nonneutralizing, FVIII-binding IgG1 antibodies, but other FVIII-binding IgG subclasses were not observed. Subgroup 3 developed transient FVIII inhibitors associated with FVIII-binding IgG1 antibodies, similar to subgroup 2. Subgroup 4 developed persistent FVIII inhibitors associated with an initial development of high-affinity, FVIII-binding IgG1 antibodies, followed by IgG3 and IgG4 antibodies. Appearance of FVIII-binding IgG3 was always associated with persistent FVIII inhibitors and the subsequent development of FVIII-binding IgG4. Some of the antibody signatures identified in HIPS could serve as candidates for early biomarkers of FVIII inhibitor development.

Introduction The efficacy and safety of recombinant factor VIII Fc fusion protein (rFVIIIFc) as an extended half‐life treatment for severe haemophilia A were demonstrated in the Phase 3 A‐LONG and Kids A‐LONG studies. Eligible subjects who completed A‐LONG and Kids A‐LONG could enrol in ASPIRE (NCT01454739), an open‐label extension study. Aim To report the long‐term safety and efficacy of rFVIIIFc in subjects with severe haemophilia A who enrolled in ASPIRE. Methods Previously treated subjects received one or more of the following regimens: individualized prophylaxis (IP), weekly prophylaxis, modified prophylaxis or episodic treatment. Subjects could switch treatment regimen at any time. The primary endpoint was inhibitor development. Results A total of 150 subjects from A‐LONG and 61 subjects from Kids A‐LONG enrolled in ASPIRE. Most subjects received the IP regimen (A‐LONG: n = 110; Kids A‐LONG: n = 59). Median (range) treatment duration in ASPIRE for subjects from A‐LONG and Kids A‐LONG was 3.9 (0.1‐5.3) years and 3.2 (0.3‐3.9) years, respectively. No inhibitors were observed (0 per 1000 subject‐years; 95% confidence interval, 0‐5.2) and the overall rFVIIIFc safety profile was consistent with prior studies. For subjects on the IP regimen, annualized bleed rates (ABR) remained low (median overall ABR for adults and adolescents was

INTRODUCTION: Recurrent bleeding in severe haemophilia B causes painful hemarthroses and reduces capacity for physical activity. Recombinant factor IX Fc fusion protein (rFIXFc) prophylaxis results in low annualised bleeding rates, with the potential to improve patients' health-related quality of life (HRQoL). AIM: To present a post hoc analysis of data from B-LONG describing change over time in patient-reported outcomes associated with pain and physical activity. METHODS: Patients (≥12 years) who received weekly dose-adjusted or interval-adjusted rFIXFc prophylaxis and completed the Haemophilia-Specific QoL questionnaire for adolescents (Haemo-QoL) or adults (Haem-A-QoL) at baseline (BL) and end of study (EoS). Individual level changes in items of the 'Physical Health' and 'Sports and Leisure' domains, categorised as 'never/rarely/seldom' or 'sometimes/often/all the time', were analysed using McNemar's test to compare distribution of responses at EoS versus BL. RESULTS: At EoS versus BL, a significantly greater proportion of patients did not experience painful swellings (64% vs. 44%; P = .004), painful joints (44% vs. 28%; P = .003) or pain when moving (54% vs. 41%; P = .026). Additionally, at EoS versus BL, patients were less likely to avoid participating in sports like football (30% vs. 8%; P = .002), avoid sports due to their haemophilia (47% vs. 27%; P = .007), or experience difficulty walking as far as they wanted (63% vs. 43%; P = .001). The proportion of patients who played sports as much as the general population was numerically increased (52% vs. 37%; P = .033) at EoS versus BL. CONCLUSION: Results of the analysis suggest that over time, rFIXFc prophylaxis is associated with significant improvements in pain and physical functioning. This contributes to previous evidence of overall HRQoL improvements in patients with haemophilia B treated with rFIXFc.

Background N8‐GP is an extended half‐life recombinant factor VIII developed for prophylaxis and treatment of bleeds in patients with hemophilia A. Objective To assess pharmacokinetic (PK) characteristics of N8‐GP in previously treated patients with severe hemophilia A, model the time spent at hemophilia thresholds of ≥1 and ≤5 IU/dL (moderate) or >5 IU/dL (mild) FVIII levels during N8‐GP prophylaxis, and investigate the relationship between N8‐GP half‐life and von Willebrand factor (vWF). Methods PK assessments were obtained from patients with severe hemophilia A (FVIII < 1 IU/dL) participating in 4 clinical trials: pathfinder 1 (20‐60 years); pathfinder 2 (12‐17 and ≥18 years); pathfinder 5 (0‐11 years), and pathfinder 7 (25‐71 years). All PK profiles were assessed after washout and considered single‐dose PK profiles. Pre‐ and postdose FVIII activity at steady state was measured at all visits. Results From 69 patients, 108 PK profiles of N8‐GP 50 IU/kg were assessed. Adults/adolescents received 50 IU/kg every 4 days, achieving mean trough levels of 3.0 IU/dL (95% confidence interval, 2.6‐3.5, adults) and 2.7 IU/dL (1.8‐4.0, adolescents). Children received 60 IU/kg twice weekly, leading to mean trough levels of 1.2 IU/dL (0.8‐1.6, 0‐ to 5‐year‐olds) and 2.0 IU/dL (1.5‐2.7, 6‐ to 11‐year‐olds). PK modeling predicted children dosed every 3 days and adults/adolescents dosed every 3 to 4 days would maintain FVIII levels >5 and >1 IU/dL for >80% and 100% of the time, respectively. N8‐GP half‐life correlated linearly with von Willebrand factor levels in adults/adolescents, less in children. Conclusions Prophylaxis with fixed intervals (Q4D/twice weekly) and fixed weight‐based dosing (50/60 IU/kg) ensured >1 IU/dL FVIII trough levels in both adults and children.

Objective To establish clear priorities for the care of patients with acquired hemophilia A (AHA) by proposing 10 key principles of practical, holistic AHA management. Method These principles were developed by the Zürich Haemophilia Forum, an expert panel of European hemophilia specialists comprising physicians and nursing and laboratory specialists. Results The 10 proposed principles for AHA care are as follows: (a) Improving initial diagnosis of AHA; (b) Differential diagnosis of AHA: laboratory assessment of patients with unusual bleeding; (c) Effective communication between laboratories, physicians, and specialists; (d) Improving clinical care: networking between healthcare professionals in the treating hospital and specialist hemophilia centers; (e) Comprehensive assessment of bleeding; (f) Appropriate use of bypassing agents; (g) Long‐term follow‐up and monitoring for efficacy and safety of immunosuppressive treatment; (h) Inpatient/outpatient settings; (i) Access to innovative and disruptive treatments; (j) Promotion of international collaborative research. Conclusion The proposed principles for holistic AHA care aim to ensure swift diagnosis and optimal patient management. Key to achieving this goal is training for healthcare personnel in non‐specialist hospitals and collaboration between different specialists. We hope these principles will increase awareness of AHA in the wider medical community and catalyze efforts toward improving its practical, multidisciplinary management.

The incidence of factor IX (FIX) inhibitors in severe hemophilia B (SHB) is not well defined. Frequencies of 3-5% have been reported but most studies to date have been small, including patients with different severities, and without prospective follow up for inhibitor incidence. The study objective was to investigate the inhibitor incidence in patients with SHB followed up for to 500 exposure days (ED), the frequency of allergic reactions, and the relationship with genotypes. Consecutive previously untreated patients (PUP) with SHB enrolled into the PedNet cohort were included. Detailed data was collected for the first 50 ED, followed by the annual collection of the inhibitor status and allergic re-actions. The presence of inhibitors was defined by at least two consecutive positive samples. Additionally, data on FIX gene mutation was collected. One hundred and fifty-four PUP with SHB were included; 75% were followed up until 75 ED, and 43% until 500 ED. Inhibitors developed in 14 patients (seven high-titer). The median number of ED at inhibitor manifestation was 11 (interquartile range [IQR]: 6.5-36.5). The cumulative inhibitor incidence was 9.3% (95% Confidence Interval [CI]: 4.4-14.1) at 75 ED, and 10.2% (95% CI: 5.1-15.3) at 500 ED. Allergic reactions occurred in four (28.6%) inhibitor patients. Missense mutations were most frequent (46.8%) overall but not associated with inhibitors. Nonsense mutations and deletions with large structural changes comprised all mutations among inhibitor patients and were associated with an inhibitor risk of 26.9% and 33.3%, respectively. In an unselected, well-defined cohort of PUP with SHB, the cumulative inhibitor incidence was 10.2% at 500 ED. Nonsense mutations and large deletions were strongly associated with the risk of inhibitor development. The ‘PedNet Registry’ is registered at clinicaltrials.gov; identifier: NCT02979119.

New therapeutic agents for haemophilia with inhibitors that are in development or already licensed are expected to provide transformative treatment options. Many of these new therapies are not based on simply replacing the missing factor; new strategies include bispecific antibody technology that mimics factor VIII coagulation function (emicizumab), and inhibition of anticoagulant proteins such as tissue factor pathway inhibitor (eg PF-06741086) and antithrombin (eg fitusiran). These agents are administered subcutaneously and should significantly reduce treatment burden and increase the ability to deliver prophylaxis for patients. Limited real-world data and validated practical guidance on these recently licensed/upcoming treatments resulted in the authors convening to discuss recommendations on their use. Emicizumab is currently the only licenced nonfactor therapy; thus, our recommendations focus on this product. Target candidates for emicizumab prophylaxis are difficult-to-treat patients with haemophilia A and inhibitors and/or venous access issues, frequent bleeds and target joints. In case of breakthrough bleeding while receiving emicizumab, patients still require treatment with bypassing agents; the adjunct treatment of choice is recombinant activated factor VII. This treatment is also recommended to prevent bleeds in patients with inhibitors undergoing surgery. Our recommendations on suitable laboratory assays and monitoring new products, as well as the benefit of patient-reported outcomes (such as pain and physical activity levels), are included. We also briefly discuss future treatment options for patients with haemophilia B and inhibitors. Although these nonfactor treatments offer great promise, further data and real-world evidence are needed.

Background: Handwriting is a complex task that requires the integrity of different sensorimotor components to be performed successfully. Patients with hemophilia suffer from recurrent joint bleeds that may occur in the elbow, causing elbow dysfunction with handwriting performance impairment. In our study, we described instrumental dysgraphia that is related to functional disturbances. This pilot study aims to evaluate the handwriting performance in a group of patients with hemophilia. Methods: The study was performed at the Angelo Bianchi Bonomi Hemophilia and Thrombosis Center in Milan. Boys with severe and moderate hemophilia A and B regularly followed-up at that Center, with age between 6&ndash, 19 years, were eligible. Patients were invited to the Center for one multidisciplinary evaluation of the upper limbs that included: Clinical examination, surface electromyography, and handwriting assessment. Results: All patients, but one, completed handwriting assessment. Overall, 14/19 (74%) had abnormal handwriting, which was overt instrumental dysgraphia in six (32%). There was no difference in Hemophilia Joint Health Score (HJHS) between dysgraphic and non-dysgraphic boys, while surface electromyography (sEMG) revealed a prevalence of flexor muscles of the upper limb in dysgraphic as compared with non-dysgraphic boys. Conclusions: The rather high prevalence of instrumental dysgraphia found in this pilot study deserves a further development of this preliminary experience by increasing the number of examined patients and comparing them with a control group, including quality of life and psychological assessment.

Introduction A phase 3b extension study evaluated the long-term safety and efficacy of a recombinant fusion protein-linking coagulation factor IX (FIX) with albumin (rIX-FP) for the routine prophylaxis and on-demand treatment of bleeding in pediatric hemophilia B patients. Methods Previously treated patients aged Results Compared with their initial regimen, by the end of the study, dosing intervals were the same, extended, and shortened in 16, 4, and 4 patients, respectively. Very low annualized spontaneous bleeding rates (AsBRs) were observed; median AsBR was 0.0 for the 7- and 10-day regimens, and 1.1 for the 14-day regimen. The 7- and 14-day regimens were comparable in preventing spontaneous bleeds; mean (95% confidence interval) difference in AsBR of −1.2 (−2.6 to 0.3) bleeding episodes/year/subject. Overall, 96% of bleeding episodes were successfully treated with one or two injections of rIX-FP. Patients on a 14-day regimen maintained a mean steady-state trough FIX level of >7.2 IU/dL. No patient developed an inhibitor. Conclusion This extension study demonstrated the long-term safety and efficacy of weekly rIX-FP in pediatric patients. Additionally, it showed that adequate bleed protection can be achieved with 10- or 14-day rIX-FP regimens in selected pediatric patients while maintaining safety.

Introduction Ensuring hemostasis during invasive procedures is a challenge in patients with severe hemophilia A. This analysis evaluated efficacy and safety of BAY 94-9027, an extended-half-life recombinant factor VIII (FVIII), in the surgical setting. Materials and methods Patients participating in an open-label BAY 94-9027 clinical trial who underwent major surgery were included in the analysis. Investigator/surgeon assessment of hemostasis during surgery was the primary outcome. In addition, information about FVIII use, FVIII levels during perioperative period, bleeding complications and FVIII inhibitor development were collected. Results Data were analyzed for 26 major surgeries (orthopedic, n = 21) in 20 patients aged 13–61 years. BAY 94-9027 provided effective hemostasis during all procedures. FVIII levels 6–8 h post preoperative infusion and prior to the first follow-up infusion were in the range expected to maintain protection in the major surgery setting. The median time from preoperative infusion to the first follow-up infusion (the first infusion administered after the preoperative infusion) was 12.33 (3.6–49.9) h. No intraoperative bleeding complications occurred, and no new inhibitors developed following any surgery. Conclusions The results of the study demonstrate that BAY 94-9027 was efficacious and well tolerated in the treatment of patients undergoing major surgeries. Advantages of BAY 94-9027 include the potential for less frequent infusion and reduced factor consumption, which should simplify the management of patients during major surgery.

Giovanni Di Minno,1 Elena Santagostino,2 Massimo Morfini,3 Cosimo Ettorre,4 Dorina Cultrera,5 Erminia Baldacci,6 Eleonora Russo,7 Cristiano Gallucci7 On behalf of the Italian FusENGO B1831081 Study Group 1Department of Clinical Medicine and Surgery, Azienda Universitaria Policlinico Federico II, Naples, Italy; 2Hemophilia and Thrombosis Center, IRCCS Fondazione Ca’ Granda, Ospedale Maggiore Policlinico, Milan, Italy; 3Scientific Committee, Italian Association of Haemophilia Centres (AICE), Florence, Italy; 4Haemophilia and Thrombosis Center, Policlinico Giovanni XXIII, Bari, Italy; 5Hematology Unit, Regional Center for Hemophilia, Italy Ospedaliera-Universitaria “Policlinico – Vittorio Emanuele”, Catania, Italy; 6Hemophilia, Thrombosis, and Hematology Center, Dipartimento Biotecnologie cellulari ed Ematologia, Università la Sapienza, Rome, Italy; 7Medical Department, Pfizer srl Rome, Italy Background: FuseNGO is a relatively new device consisting of a prefilled dual-chamber syringe (DCS) that was recently introduced for the reconstitution of recombinant factor VIII. Herein, the DCS device was assessed using five questionnaires with the primary aim of evaluating patient perceptions and preferences.Methods: An observational, non-interventional, longitudinal study on 86 patients with a confirmed diagnosis of hemophilia A was carried out at 21 sites in Italy. Each patient underwent a baseline visit and final study visit within 3–6 months. Patients were administered five questionnaires: HemoPREF; Treatment Satisfaction Questionnaire for Medication (TSQM); VeritasPRO; Hemophilia Well-being Index (HWBI); Work Productivity and Activity Impairment Questionnaire (WPAI) + Classroom Impairment Questions (CIQ): Hemophilia Specific (HS).Results: Compared to baseline, scores for HemoPREF were higher at follow-up; significant increases in the percentage of positive responses were seen for all questions regarding the ease of use (P70% in the VeritasPRO questionnaire, and the majority of patients reported in the HWBI that hemophilia A did not affect their lives in a significant way. The perceived level of overall impairment was 30% as reported in the WPAI + CIQ: HS, indicating little impairment. There were no safety concerns.Conclusion: Considering patient-reported outcomes, the DCS device was associated with easier preparation, storage, disposal of equipment, and overall use. Of particular note, preparation times were reduced by around 50%. The majority of patients were satisfied with the device and overall adherence scores were high. Considering these results, the device has the potential to increase adherence to therapy and, possibly, reduce healthcare costs. Keywords: factor VIII delivery, device, hemophilia A, patient satisfaction, adherence

Curry, Nicola/0000-0002-3849-0688; Escobar, Miguel/0000-0002-2944-0240 WOS: 000470929100022 PubMed: 30817066 Introduction Turoctocog alfa pegol (N8-GP) is a site-specific, 40 kDa glycoPEGylated recombinant factor VIII (FVIII) product with an extended half-life. The comprehensive main phase of the pivotal pathfinder 2 trial showed N8-GP dosed every 4 days (Q4D) provided favourable safety and efficacy for preventing bleeds in 175 patients with haemophilia A. Aim and methods We investigated the safety and efficacy of N8-GP prophylaxis when administered weekly (Q7D) for 24 weeks to patients with low bleeding rates in the pathfinder 2 extension trial. Patients (>= 12 years) with 50% of patients experienced no bleeds. Median ABR for overall, joint, spontaneous, traumatic and muscle was 0.00 for both cohorts. Overall estimated success rate for treating bleeding episodes was 87.5%; 94.7% of bleeds were controlled with

TO THE EDITOR: Inhibitory antibodies (inhibitors) against factor VIII (FVIII) develop in 25% to 35% of previously untreated patients (PUPs) with severe hemophilia A (SHA). It is the most serious complication of classic hemophilia treatment.[1][1][⇓][2]-[3][3] Most inhibitors develop during the

In children with severe haemophilia A, inhibitors to factor VIII (FVIII) usually develop during the first 50 treatment exposure days and are classified as low or high titre depending on the peak inhibitor titre being greater or less than 5 Bethesda units/mL (BU/mL). Classification of the inhibitor may change with time, as some low-titre inhibitors progress to high titre following re-exposure to FVIII concentrate. The aim of this study was to investigate potential risk factors for such a progression in children with severe haemophilia A and newly diagnosed inhibitors. This study was a follow-up study of the PedNet Registry and included 260 children with severe haemophilia A and inhibitors born between 1990 and 2009 and recruited consecutively from 31 haemophilia centres. Clinical and laboratory data were collected from the date of each child's first positive inhibitor test for at least 3 years. At the time of first positive inhibitor test, 49% (n = 127) had low-titre inhibitors, with 50% of them progressing to high titre and only 25% maintaining low titres. The FVIII gene (F8) mutation type was known in 247 patients (95%), and included 202 (82%) null mutations. The progression to high-titre inhibitors was associated with null F8 mutations (odds ratio [OR]: 2.6; 95% confidence interval [CI]: 1.0–6.5), family history of inhibitors (OR: 7.2; 95% CI: 1.8–28.4) and the use of high-dose immune tolerance induction, defined as ≥100 IU FVIII concentrate/kg/d (OR: 3.9; 95% CI: 1.5–10.0). These results suggest that high-dose immune tolerance induction should be avoided as the initial strategy in patients who develop low-titre FVIII inhibitors.

Elena Santagostino Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Fondazione IRCCS Ca’ Granda, Ospedale Maggiore Policlinico, Milan, Italy Abstract: Advances in recombinant technology and knowledge about coagulation factor VIII (FVIII) are building a platform for new therapeutic options in patients with hemophilia A. The development of turoctocog alfa, a novel, high-purity, third-generation, B-domain truncated recombinant FVIII, has been produced and formulated without the use of animal-derived or human serum-derived components, in the wake of understanding of the new biochemical characteristics of FVIII, namely its protein structure, and glycosylation and sulfating patterns. Culture conditions and a five-step purification process have been developed to optimize the safety of turoctocog alfa. The results of two pilot clinical trials using turoctocog alfa confirmed high safety levels, with no patient developing inhibitors during the period of observation. The purpose of this review is to describe briefly the molecular and biological properties of turoctocog alfa, together with details of its clinical development, with emphasis on the needs of patients with hemophilia A. Keywords: hemophilia A, recombinant factor VIII, turoctocog alfa, purification, inhibitor, safety

PubMedID: 25273984 Recombinant factor VIII (rFVIII) products provide a safe and efficacious replacement therapy for prevention and treatment of bleeding episodes in patients with haemophilia A. The present investigations from the multinational, open-label guardian™ clinical trials assessed the haemostatic response of turoctocog alfa (NovoEight®), a rFVIII product, in patients with severe haemophilia A (FVIII ? 1%) undergoing surgery. All patients had a minimum of 50 exposure days to any FVIII product prior to surgery and no history of inhibitors. A total of 41 procedures (13 orthopaedic, 19 dental and 9 general) were performed in 33 patients aged 4-59 years. Of the 41 procedures, 15 were major surgeries in 13 patients and 26 were minor surgeries in 21 patients. The success rate for haemostatic response was 100% (success was defined as 'excellent' or 'good' haemostatic outcome). Turoctocog alfa consumption on the day of surgery ranged from 27 to 153 IU kg-1. The mean daily dose declined over time, while retaining adequate FVIII coverage as measured by trough levels. Overall, no safety issues were identified. No thrombotic events were observed and none of the patients developed FVIII inhibitors. In conclusion, the present results show that turoctocog alfa was effective in controlling blood loss by obtaining a sufficient haemostatic response in patients with severe haemophilia A undergoing surgery. © 2014 The Authors. Haemophilia Published by John Wiley & Sons Ltd.

Patients with haemophilia A (and their physicians) may be reluctant to switch factor VIII (FVIII) concentrates, often due to concerns about increasing the risk of inhibitors; this reluctance to switch may contribute to patients missing the clinical benefits provided by the arrival of new factor VIII products. This topic was explored at the Eleventh Zurich Haemophilia Forum. Clinical scenarios for which product switching may be cause for concern were discussed; when there is a clinical need, there are no absolute contraindications to switching, but some patients (e.g. previously untreated patients and those undergoing elective surgery) may require more careful consideration. Both patient and physician surveys indicate that the reluctance to switch, and the fear of inhibitor development, does not appear to be evidence based. The evaluation of more recent data did not support previous studies suggesting that particular products (e.g. recombinant vs. plasma-derived and full length vs. B-domain modified) may be associated with increased risk. In addition, data from three national product switches showed that switching was not associated with increased inhibitor risk, but highlighted the need for regular inhibitor testing and for a centralised, unbiased database of inhibitor incidence. To conclude, current evidence does not suggest that switching products significantly influences inhibitor development.

Background Vatreptacog alfa, a recombinant factor VIIa (rFVIIa) analog with three amino acid substitutions and 99% identity to native FVIIa, was developed to improve the treatment of hemophilic patients with inhibitors. Objectives To confirm the safety and assess the efficacy of vatreptacog alfa in treating bleeding episodes in hemophilic patients with inhibitors. Patients and methods In this international, multicenter, randomized, double-blind, active-controlled, crossover, confirmatory phase III trial (adept™2) in patients with hemophilia A or B and inhibitors, bleeds were randomized 3 : 2 to treatment with vatreptacog alfa (one to three doses at 80 μg kg−1) or rFVIIa (one to three doses at 90 μg kg−1). Treatment failures after three doses of trial product (TP) were managed according to the local standard of care. Results In the 72 patients enrolled, 567 bleeds were treated with TP. Both vatreptacog alfa and rFVIIa gave 93% effective bleeding control at 12 h. Vatreptacog alfa was superior to rFVIIa in secondary efficacy outcomes, including the number of doses used to treat a bleed and sustained bleeding control 24–48 h after the first dose. Eight patients (11%) developed antibodies against vatreptacog alfa, including four with cross-reactivity against rFVIIa and one with an in vitro neutralizing effect to vatreptacog alfa. Conclusions This large randomized controlled trial confirmed the well-established efficacy and safety profile of rFVIIa, and showed that vatreptacog alfa had similar or better efficacy than rFVIIa. However, because of the development of anti-drug antibodies, a positive benefit–risk profile is unlikely to be achieved with vatreptacog alfa.

Recombinant VIII (rVIII)-SingleChain is a novel B-domain–truncated recombinant factor VIII (rFVIII), comprised of covalently bonded factor VIII (FVIII) heavy and light chains. It was designed to have a higher binding affinity for von Willebrand factor (VWF). This phase 1/3 study investigated the efficacy and safety of rVIII-SingleChain in the treatment of bleeding episodes, routine prophylaxis, and surgical prophylaxis. Participants were ≥12 years of age, with severe hemophilia A (endogenous FVIII

A global phase 3 study evaluated the pharmacokinetics, efficacy, and safety of recombinant fusion protein linking coagulation factor IX with albumin (rIX-FP) in 63 previously treated male patients (12-61 years) with severe hemophilia B (factor IX [FIX] activity ≤2%). The study included 2 groups: group 1 patients received routine prophylaxis once every 7 days for 26 weeks, followed by either 7-, 10-, or 14-day prophylaxis regimen for a mean of 50, 38, or 51 weeks, respectively; group 2 patients received on-demand treatment of bleeding episodes for 26 weeks and then switched to a 7-day prophylaxis regimen for a mean of 45 weeks. The mean terminal half-life of rIX-FP was 102 hours, 4.3-fold longer than previous FIX treatment. Patients maintained a mean trough of 20 and 12 IU/dL FIX activity on prophylaxis with rIX-FP 40 IU/kg weekly and 75 IU/kg every 2 weeks, respectively. There was 100% reduction in median annualized spontaneous bleeding rate (AsBR) and 100% resolution of target joints when subjects switched from on-demand to prophylaxis treatment with rIX-FP (P< .0001). The median AsBR was 0.00 for all prophylaxis regimens. Overall, 98.6% of bleeding episodes were treated successfully, including 93.6% that were treated with a single injection. No patient developed an inhibitor, and no safety concerns were identified. These results indicate rIX-FP is safe and effective for preventing and treating bleeding episodes in patients with hemophilia B at dosing regimens of 40 IU/kg weekly and 75 IU/kg every 2 weeks. This trial was registered at www.clinicaltrials.gov as #NCT0101496274.

Giorgio L Colombo1,2, Sergio Di Matteo2, Maria Elisa Mancuso3, Elena Santagostino31University of Pavia, School of Pharmacy, Pavia, Italy; 2S.A.V.E. Studi Analisi Valutazioni Economiche, Milan, Italy; 3Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, ItalyBackground: Individuals with severe hemophilia A have reduced blood levels of clotting factor VIII (FVIII) leading to recurrent bleeding into joints and muscles. Primary prophylaxis with clotting factor concentrates started early in childhood prevents joint bleeds, thus avoiding joint damage and improving people's quality of life. There remain significant differences in the implementation of primary prophylaxis worldwide mainly due to the cost of prophylaxis compared with treatment on demand.Objective: To evaluate the cost-effectiveness of primary prophylaxis with FVIII concentrates versus secondary prophylaxis, versus treatment on demand, and versus a "hybrid" (primary prophylaxis followed by on-demand treatment in adults) in individuals with severe hemophilia A.Methods: A Markov model was developed and run using different sources of clinical, cost, and utility data. The model was populated with a hypothetical cohort of 100 individuals with severe hemophilia A. The perspective of the Italian National Health System was used.Results: The baseline results showed that primary and secondary prophylaxis is cost-effective compared both with treatment on demand and with a hybrid strategy. The incremental costs per quality-adjusted life-year gained for individuals with hemophilia A receiving primary and secondary prophylaxis were €40,229 to €40,236 versus an on-demand strategy. However, the sensitivity analyses performed showed that the results were sensitive to the unit cost of clotting FVIII, bleeding frequency, and the discount rate.Conclusion: Although primary prophylaxis is a costly treatment, our results show that it is cost-effective compared with treatment on demand.Keywords: hemophilia, cost-utility, factor VIII, prophylaxis, treatment on demand, quality of life

The development of inhibitory antibodies to factor VIII (FVIII) is a major obstacle in using this clotting factor to treat individuals with hemophilia A. Patients with a congenital absence of FVIII do not develop central tolerance to FVIII, and therefore, any control of their FVIII-reactive lymphocytes relies upon peripheral tolerance mechanisms. Indoleamine 2,3-dioxygenase 1 (IDO1) is a key regulatory enzyme that supports Treg function and peripheral tolerance in adult life. Here, we investigated the association between IDO1 competence and inhibitor status by evaluating hemophilia A patients harboring F8-null mutations that were either inhibitor negative (n = 50) or positive (n = 50). We analyzed IDO1 induction, expression, and function for any relationship with inhibitor occurrence by multivariable logistic regression and determined that defective TLR9-mediated activation of IDO1 induction is associated with an inhibitor-positive status. Evaluation of experimental hemophilic mouse models with or without functional IDO1 revealed that tryptophan metabolites, which result from IDO1 activity, prevent generation of anti-FVIII antibodies. Moreover, treatment of hemophilic animals with a TLR9 agonist suppressed FVIII-specific B cells by a mechanism that involves IDO1-dependent induction of Tregs. Together, these findings indicate that strategies aimed at improving IDO1 function should be further explored for preventing or eradicating inhibitors to therapeutically administered FVIII protein.

Summary Background The development of neutralizing alloantibodies (inhibitors) is the most serious complication of factor VIII (FVIII) replacement therapy in patients with hemophilia A. Unlike previously untreated patients, no definite risk factors for inhibitor development are known for previously treated patients (PTPs). The investigation of the development of inhibitors in PTPs is hindered by several methodological limitations in the available literature. We conducted a systematic review to account for these limitations. Methods We considered the studies reporting on PTPs that were included in the Wight and Paisley meta-analysis and a systematic search of MEDLINE, EMBASE, and The Cochrane Library was conducted to identify studies published after 2003. Studies that investigated the development of inhibitors in hemophilia A PTPs who were treated with any type of FVIII concentrate and that included at least 25 patients with follow-up were included in the analysis. Results Thirty-three independent cohorts of PTPs with 4323 subjects and 43 incident de novo inhibitors were found and analyzed. The pooled incidence rate of inhibitor development for the 25 studies providing data on follow-up was 3 (95% confidence interval 1–4) per 1000 person-years. A significant association was not found between putative risk factors and inhibitor development in PTPs at meta-regression analysis and subgroup analysis, but the model was sensitive enough to the inclusion of the reports on the Belgian-Dutch experience with a highly immunogenic factor VIII. Conclusion We confirmed a low overall rate of de novo inhibitors in PTPs, without any significant effect of putative predictors, including the type of factor VIII concentrate.

Summary The Health Commission of the Conference between the Italian State and Regions recognized the need to establish an institutional accreditation model for Haemophilia Centres (HCs) to be implemented by 21 Regions in order to provide patients with haemophilia and allied inherited coagulations disorders with high and uniform standards of care. The Italian National Blood Centre, on behalf of the Commission, convened a panel of clinicians, patients, experts, representatives from Regions and Ministry of Health. The agreed methodology included: systematic literature review and best practice collection, analysis of provisions and regulations of currently avalable services, priority setting, definition of principles and criteria for the development of recommendations on the optimal requirements for HCs. The result was the formulation of two recommendations sets. Two sets of recommendations were produced. The first concerns regional policy planning, in which the following aspects of comprehensive haemophilia care should be considered for implementation: monitoring and auditing, multidisciplinary approach to clinical care, protocols for emergency management, home treatment and its monitoring, patient registries, drug availability and procurement, recruitment and training of health care professionals. The second set concerns the accreditation process and lists 23 organizational requirements for level 1 HCs and 4 additional requirements for level 2 HCs. These recommendations help to provide Italian Regional Health Authorities with an organizational framework for the provision of comprehensive care to patients with inherited coagulation disorders based on current scientific evidence.

SummaryThe aim of this study was to develop a simplified ultrasound scanning procedure and scoring method, named Haemophilia Early Arthropathy Detection with UltraSound [HEAD-US], to evaluate joints of patients with haemophilic arthropathy. After an initial consensus-based process involving a multidisciplinary panel of experts, three comprehensive and evidence-based US scanning procedures to image the elbow, knee and ankle were established with the aim to increase sensitivity in detection of early signs of joint involvement while keeping the technique easy and quick to perform. Each procedure included systematic evaluation of synovial recesses and selection of a single osteochondral surface for damage analysis. Based on expert consensus, a simplified scoring system based on an additive scale was created to define the joint status and, in perspective, to offer a tool to evaluate disease progression and monitor the result of treatment in follow-up studies.

SummaryMany studies have reported an increased incidence of inhibitors in previously untreated patients (PUPs) with severe haemophilia A after the introduction of recombinant products. It was the objective of this study to investigate whether the inhibitor incidence has increased between 1990 and 2009 in an unselected cohort of PUPs with severe haemophilia A (FVIII < 1 %). Patients were consecutively recruited from 31 haemophilia treatment centres in 16 countries and followed until 50 exposure days or until inhibitor development. Inhibitor development was studied in five-year birth cohorts comparing cumulative incidences. Furthermore the risk for inhibitor development per five-year birth cohort was studied using multivariable Cox regression, adjusting for potential genetic and treatment-related confounders. A total of 926 PUPs were included with a total cumulative inhibitor incidence of 27.5 %. The inhibitor incidence increased from 19.5 % in 1990-1994 (lowest) to 30.9 % in 2000-2004 (highest; p-value 0.011). Low titre inhibitor incidence increased from 3.1 % in 1990-1994 to 10.5 % in 2005-2009 (p-value 0.009). High titre inhibitor incidences remained stable over time. After 2000, risk of all inhibitor development was increased with adjusted hazard ratios 1.96 (95 % CI 1.06-2.83) in 2000-2004 and 2.34 (1.42-4.92) in 2005-2009. Screening for inhibitors was intensified over this 20-year study period from a median of 1.9 to 2.9 tests/year before 2000 to 2.7 to 4.3 tests/ year after 2000. In conclusion, the cumulative inhibitor incidence has significantly increased between 1990 and 2009. The high titre inhibitor incidence has remained stable.

Rapid control of bleeding is the key to reducing bleeding complications and thereby preserving joint and musculoskeletal function in haemophilia patients with inhibitors. However, this requires early diagnosis following the onset of bleeding and strategies for rapid treatment in an outpatient setting. Overarching themes on the need for speed in managing bleeds in haemophilia patients were examined by a panel of clinicians experienced in managing inhibitor patients and joint disease during the Third Zürich Haemophilia Forum on 8 May 2009. This report summarizes the opinions of the panel on how to achieve rapid bleeding control in inhibitor patients and areas that were identified by the panel for future research or as needing new consensus guidelines. The consensus was that home treatment should be established for haemophilia patients with inhibitors, as it is associated with a faster time to treatment, as well as improvements in the quality of life of patients and their carers. In addition, as improved haemostatic control now allows inhibitor patients to participate in a wider range of physical activities, specific guidelines are required on which types of sport and work are appropriate. It was agreed that clear, systematic approaches are needed for early diagnosis of joint and muscle bleeds in inhibitor patients, which could facilitate rapid treatment. There may be opportunities for exploiting new diagnostic techniques from osteoarthritis to enable earlier diagnosis of haemophilic arthropathy. Overall, it was concluded that greater emphasis should be placed on education and patients' psychological needs, to enable inhibitor patients to cope up more effectively with their disease.

Background Long-term survival of HIV-1 infected individuals is usually achieved by continuous administration of combination antiretroviral therapy (ART). An exception to this scenario is represented by HIV-1 infected nonprogressors (NP) which maintain relatively high circulating CD4+ T cells without clinical symptoms for several years in the absence of ART. Several lines of evidence indicate an important role of the T-cell response in the modulation of HIV-1 infection during the acute and chronic phase of the disease. Results We analyzed the functional and the differentiation phenotype of Nef- and Tat-specific CD8+ T cells in a cohort of HIV-1 infected NP in comparison to progressors, ART-treated seropositive individuals and individuals undergoing a single cycle of ART interruption. We observed that a distinctive feature of NP is the presence of Nef-specific CD45RA+ CD8+ T cells secreting MIP-1beta but not IFN-gamma. This population was present in 7 out of 11 NP. CD45RA+ IFN-gammaneg MIP-1beta+ CD8+ T cells were not detected in HIV-1 infected individuals under ART or withdrawing from ART and experiencing a rebounding viral replication. In addition, we detected Nef-specific CD45RA+ IFN-gammaneg MIP-1beta+ CD8+ T cells in only 1 out of 10 HIV-1 infected individuals with untreated progressive disease. Conclusion The novel antigen-specific CD45RA+ IFN-gammaneg MIP-1beta+ CD8+ T cell population represents a new candidate marker of long-term natural control of HIV-1 disease progression and a relevant functional T-cell subset in the evaluation of the immune responses induced by candidate HIV-1 vaccines.

Summary. Background: Different rates of inhibitor development after either plasma-derived (pdFVIII) or recombinant (rFVIII) FVIII have been suggested. However, conflicting results are reported in the literature. Objectives: To systematically review the incidence rates of inhibitor development in previously untreated patients (PUPs) with hemophilia A treated with either pdFVIII or rFVIII and to explore the influence of both study and patient characteristics. Methods: Summary incidence rates (95% confidence interval) from all included studies for both pdFVIII and rFVIII results were recalculated and pooled. Sensitivity analysis was used to investigate the effect of study design, severity of disease and inhibitor characteristics. Meta-regression and analysis-of-variance were used to investigate the effect of covariates (testing frequency, follow-up duration and intensity of treatment). Results: Two thousand and ninety-four patients (1167 treated with pdFVIII, 927 with rFVIII; median age, 9.6 months) from 24 studies were investigated and 420 patients were observed to develop inhibitors. Pooled incidence rate was 14.3% (10.4–19.4) for pdFVIII and 27.4% (23.6–31.5) for rFVIII; high responding inhibitor incidence rate was 9.3% (6.2–13.7) for pdFVIII and 17.4% (14.2–21.2) for rFVIII. In the multi-way anova study design, study period, testing frequency and median follow-up explained most of the variability, while the source of concentrate lost statistical significance. It was not possible to analyse the effect of intensity of treatment or trigger events such as surgery, and to completely exclude multiple reports of the same patient or changes of concentrate. Conclusions: These findings underscore the need for randomized controlled trials to address whether or not the risk of inhibitor in PUPs with hemophilia A differs between rFVIII and pdFVIII.

Immune tolerance induction (ITI) is the only strategy proven to eradicate persistent inhibitors in severe haemophilia A patients. Thirty years experience has shown high success rates (60-80%) with heterogeneous dose regimens and has led to the identification of clinical features that define the patients' prognostic profile. Children with recently diagnosed inhibitors are the best candidates for ITI and adequate management may further contribute to improve the short- and long-term ITI outcome. In these patients inhibitor eradication represents a cost-effective option because it enables the restoration of FVIII prophylaxis and consequently prevents arthropathy development. Adults with long-standing inhibitors often show bad predictors of ITI outcome, however, ITI may be considered as a suitable and cost-effective approach in cases with frequent bleeds that are not satisfactorily controlled by by-passing treatment and/or when orthopaedic surgery is needed. Optimal ITI regimens should be established in these different settings and randomized trials are addressing these issues. This article reviews the available literature evidence and clinical implications with current recommendations on ITI management, and highlights the issues still unsolved.

Development of inhibitors is a severe complication of haemophilia posing many management challenges. While a long-term goal in inhibitor patients is eradication of inhibitors through immune tolerance induction, bypassing agents such as recombinant activated factor VII (rFVIIa) and activated prothrombin complex concentrate (aPCC) are essential for control of bleeding episodes. Paediatric patients with haemophilia and inhibitors are at particular risk of recurrent haemarthroses, and management of these patients should seek to avoid joint damage and support the child's full social and physical development. Current options for management of bleeding complications include on-demand treatment of acute bleeding episodes, secondary prophylaxis to avoid recurrent bleeds and surgery to treat affected joints. There is also a rationale for adopting prophylactic approaches to prevent bleeding in inhibitor patients, allowing this group similar opportunities for protection against arthropathy development as are given to non-inhibitor patients. This paper, based on a roundtable meeting of haematology experts at the first Zurich Haemophilia Forum in May 2008, reviews the current evidence supporting more intense and prophylactic approaches to manage bleeding risk in paediatric haemophilia patients with inhibitors, and highlights the need for investigations of primary prophylaxis in this vulnerable patient group, to support best long-term outcome.

We recommend prophylaxis in haemophilic children with an inhibitor as a way of preventing the musculoskeletal impairment that is likely to affect them. This approach has been used for children without inhibitors with excellent results. If prophylaxis is not feasible, we suggest that intensive on-demand treatment should be given. Two agents, recombinant activated FVII (rFVIIa) and activated prothrombin complex concentrates (aPCC), are currently used to control haemostasis either for prophylaxis or intensive on-demand treatment. As it is recombinant, rFVIIa would seem more appropriate to be employed in children. aPCC could be used in adults, or in the event of an unsatisfactory response to rFVIIa. We recommend prophylaxis or, at least, intensive on-demand treatment in haemophilia children with inhibitors. Both rFVIIa and aPCC are being used for this purpose. It would seem that rFVIIa might be more appropriate for children as it is a recombinant product. Nevertheless, after skeletal maturity (in adults), both agents could be used indistinctively (taking into consideration that FEIBA is a plasma-derived product). We still need more well-designed comparative studies in order to be able to assert that our consensus-based conclusion is evidence based. In orthopaedic surgery, both aPCC and rFVIIa have been reported to be effective in controlling perioperative haemostasis, although in practice most centres have so far used rFVIIa for their orthopaedic procedures. We recommend rehabilitation programmes for all patients with inhibitors in order to mitigate the disabling and handicapping impact of their condition and thereby enable them to achieve social integration. Programmes for haemophilic children without inhibitors can be applied to children with inhibitors but should be individually tailored.

In haemophilia A, continuous infusion (CI) of FVIII perioperatively provides a more constant FVIII level than conventional bolus injections, avoiding low trough levels that could increase bleeding risk. Due to the low number of surgical cases in clinical trials, especially in haemophilia, more information on the clinical practice of CI from observational studies is helpful. We aimed to evaluate the effectiveness and safety of CI with recombinant factor VIII formulated with sucrose (rFVIII-FS) in a typical surgery practice setting. This was a non-interventional study in 12 centres. Patients with severe haemophilia A who received rFVIII-FS by CI during and after surgery were included in this study if they had more than 150 exposure days (EDs) to any FVIII product and had no history of inhibitors before CI. Patients were observed during the entire course of CI, with monitoring up to 3 months thereafter. Twenty-five patients with 28 surgeries were included in the analysis. Median age was 51.7 (range 10-75). Most (75%; 21/25) patients underwent orthopaedic surgeries. The median dose of rFVIII-FS consumed during CI was 376 IU kg(-1) (range 157.9-3605.6 IU kg(-1)) with a greater median dose for orthopaedic surgeries (424.0 IU kg(-1)) compared to non-orthopaedic surgeries (278.5 IU kg(-1)). 95% of all FVIII measurements (214/224) were on target. Efficacy and tolerability were rated as good/excellent in 89.3% (25/28) of surgeries. No inhibitors were observed during or after surgery. This study demonstrates the effectiveness of CI with rFVIII-FS during surgery in patients with severe haemophilia A in a clinical practice setting.

This case-control study investigated the interactions between genetic and environmental factors and inhibitor development in 108 children with haemophilia A exclusively treated with recombinant factor VIII (FVIII). Sixty patients with inhibitors were compared with 48 inhibitor-free controls. Family history of inhibitors and null mutations in the FVIII gene were more prevalent in cases than in controls (20% vs. 2%, P = 0.001 and 83% vs. 64%, P = 0.04, respectively). On the other hand, there was no difference between cases and controls for such putative risk factors of inhibitor development as amniocentesis/villocentesis, premature/caesarean birth, breast-feeding, treatment during infections/vaccinations, surgical procedures and central nervous system bleeding. A trend was found for an increased risk of inhibitor development in children first treated at a young age (

Recombinant fusion protein linking recombinant coagulation factor IX with recombinant albumin (rIX-FP; Idelvion®††License approval received March 2016 in the USA) is an innovative new treatment designed to extend the half-life of factor IX (FIX) and ease the burden of care for hemophilia B patients. The rIX-FP clinical development program – PROLONG-9FP – is in its advanced phases, with pivotal studies in previously treated adults, adolescents, and pediatrics now completed. Across all age groups studied, rIX-FP has demonstrated a markedly improved pharmacokinetic profile compared with plasma-derived and recombinant FIX treatments, with a 30–40% higher incremental recovery, an approximately 5-fold longer half-life, a lower clearance, and a greater area under the curve. rIX-FP has been very well tolerated with an excellent safety profile. In the pivotal studies, there have been no reports of FIX inhibitors or antidrug antibodies, and few treatment-related adverse events have been observed. Prophylactic regimens of rIX-FP administered once weekly to once every 14 days have been highly effective. When used for surgical prophylaxis, a single infusion of rIX-FP has been sufficient to maintain hemostasis, even during major orthopedic surgery. An ongoing study is now enrolling previously untreated patients and evaluating the possibility of extending the dosing interval to every 21 days. There is little doubt that rIX-FP will transform the treatment of hemophilia B.