The burden of bleeding in haemophilia: is one bleed too many?

Estimating the potential cost of a high dose immune tolerance induction (ITI) therapy relative to the cost of a combined therapy of a low dose ITI therapy with bypassing agent prophylaxis

INTRODUCTION

The International Immune Tolerance Study (I-ITI) demonstrated comparable success rates between low (FVIII 50 IU/kg/TIW) and high dose (FVIII 200 IU/kg/day) regimens. While costlier, the high dose ITI regimen achieved shorter time-to-treatment success with fewer bleeding episodes compared to the low dose ITI regimen. Adding bypassing agent prophylaxis (BAP) to a low dose ITI regimen may reduce bleeding while still being less costly than high dose ITI.

AIM AND METHODS

An economic model was developed to compare high dose ITI to low dose ITI with BAP. All model inputs were derived from clinical trials. The I-ITI study indicated a median time to negative inhibitor titre of 4.6 and 9.2 months and average number of bleeds/patient of 4.2 and 9.9 for the high and low dose regimens respectively. Based on the BAP trials, aPCC (85 U/kg/TIW) and rFVIIa (90 μg/kg/day) achieved a 62% and 45% reduction in bleeding frequency respectively. Cost analysis was from a US third party payer perspective and limited to drug costs. One-way, two-way and probabilistic sensitivity analyses were performed.

RESULTS

Costs of low dose ITI with aPCC prophylaxis until negative inhibitor titre is achieved was 24.0% less compared to high dose ITI. Low dose ITI with rFVIIa prophylaxis cost 46.5% more compared to high dose ITI. Model results were robust in the majority of the sensitivity analyses.

CONCLUSION

A low dose ITI regimen with aPCC prophylaxis may be cost saving compared to a high dose ITI regimen with the potential to reduce morbidity by lowering the risk for breakthrough bleeds.

Hemophilia Care in the Pediatric Age

Hemophilia is the most common of the severe bleeding disorders and if not properly managed since early infancy can lead to chronic disease and lifelong disabilities. However, it enjoys the most efficacious and safe treatment among the most prevalent monogenic disorders. Hemophilia should be considered in the neonatal period in the case of unusual bleeding or in the case of positive family history. Later, hemophilia should be suspected mainly in males because of abnormal bruising/bleeding or unusual bleeding following invasive procedures-for example, tonsillectomy or circumcision. Prophylactic treatment that is started early with clotting-factor concentrates has been shown to prevent hemophilic arthropathy and is, therefore, the gold standard of care for hemophilia A and B in most countries with adequate resources. Central venous access catheters and arterovenous fistulas play an important role in the management of hemophilia children requiring repeated and/or urgent administration of coagulation factor concentrates. During childhood and adolescence, personalized treatment strategies that suit the patient and his lifestyle are essential to ensure optimal outcomes. Physical activity is important and can contribute to better coordination, endurance, flexibility and strength. The present article focuses also on questions frequently posed to pediatric hematologists like vaccinations, day-care/school access and dental care.

Treatment and Prevention of Bleeds in Haemophilia Patients with Inhibitors to Factor VIII/IX

The development of alloantibodies neutralising therapeutically administered factor (F) VIII/IX (inhibitors) is currently the most severe complication of the treatment of haemophilia. When persistent and at a high titre, inhibitors preclude the standard replacement treatment with FVIII/FIX concentrates, making patients’ management challenging. Indeed, the efficacy of bypassing agents, i.e., activated prothrombin complex concentrates (aPCC) and recombinant activated factor VII (rFVIIa), needed to overcome the haemostatic interference of the inhibitor, is not comparable to that of factor concentrates. In addition, the therapeutical response is unpredictable, with a relevant inter-individual and even intra-individual variability, and no laboratory assay is validated to monitor the efficacy and safety of the treatment. As a result, inhibitor patients have a worse joint status and quality of life compared to inhibitor-free subjects and the eradication of the inhibitor by immune tolerance induction is the preeminent therapeutic goal, particularly in children. However, over the last decades, treatment with bypassing agents has been optimised, allowing home treatment and the individualisation of regimens aimed at improving clinical outcomes. In this respect, a growing body of evidence supports the efficacy of prophylaxis with both bypassing agents in reducing bleeding rates and improving the quality of life, although the impact on long-term outcomes (in particular on preventing/reducing joint deterioration) is still unknown. This review offers an update on the current knowledge and practice of the use of bypassing agents in haemophiliacs with inhibitors, as well as on debated issues and unmet needs in this challenging setting.

Pain and pain management in haemophilia

Joint pain is common in haemophilia and may be acute or chronic. Effective pain management in haemophilia is essential to reduce the burden that pain imposes on patients. However, the choice of appropriate pain-relieving measures is challenging, as there is a complex interplay of factors affecting pain perception. This can manifest as differences in patients’ experiences and response to pain, which require an individualized approach to pain management. Prophylaxis with factor replacement reduces the likelihood of bleeds and bleed-related pain, whereas on-demand therapy ensures rapid bleed resolution and pain relief. Although use of replacement or bypassing therapy is often the first intervention for pain, additional pain relief strategies may be required. There is an array of analgesic options, but consideration should be paid to the adverse effects of each class. Nevertheless, a combination of medications that act at different points in the pain pathway may be beneficial. Nonpharmacological measures may also help patients and include active coping strategies; rest, ice, compression, and elevation; complementary therapies; and physiotherapy. Joint aspiration may also reduce acute joint pain, and joint steroid injections may alleviate chronic pain. In the longer term, increasing use of prophylaxis or performing surgery may be necessary to reduce the burden of pain caused by the degenerative effects of repeated bleeds. Whichever treatment option is chosen, it is important to monitor pain and adjust patient management accordingly. Beyond specific pain management approaches, ongoing collaboration between multidisciplinary teams, which should include physiotherapists and pain specialists, may improve outcomes for patients.

Understanding adherence to treatment and physical activity in children with hemophilia: The role of psychosocial factors

The objective of this study was to identify psychosocial factors to explain intentions of children and adolescents with hemophilia to adhere to recommendations for self-care. Twenty-four patients with hemophilia A and B, aged 6-18 years old, and their parents, completed a survey. Measures assessed factors from the theory of planned behavior, physical activity, and medical treatment adherence. The results indicate that past behaviors, attitudes, and subjective norms explained a large proportion of the intention to engage in future nonrecommended physical activity. This study supports the need to investigate motivational factors underlying behaviors in larger scale studies and identifies targets for future interventions.

Determining the health-related quality of life in individuals with haemophilia in developing economies: results from the Brazilian population

INTRODUCTION

Several studies show the negative impact of haemophilia in health-related quality of life (HRQOL). This issue is not well explored in developing countries.

OBJECTIVES

This cross-sectional study aimed to evaluate the HRQOL and its associated factors in patients with haemophilia A/B in Brazil. Data were collected by questionnaire and in medical records, including a Portuguese version of Haem-A-Qol.

RESULTS

Brazilian patients were invited to the study and 175 participants (147 haemophilics A and 28 haemophilics B) were included. The total score of the Haem-A-QoL had a median of 36.96 (range of 0-100), with worse performance in 'sport and leisure' and best on 'relationships' fields. HRQOL was worst among the older participants, the less educated, non-white, non-working, who were hospitalized in the last year, who did not have a single medical consultation and among those with the highest number of affected joints. Moreover, patients with hepatitis B had a significantly worse HRQOL in the domain 'sports and leisure', also observed in married patients. Otherwise, married individuals reported better HRQOL on 'dealing with the disease' domain. Patients with haemophilia B reported worse HRQOL in the domain 'self-perception'.

CONCLUSION

The results obtained could be helpful in guidance of haemophilia treatment which is determinant to improve HRQoL of the most vulnerable groups of patients. This work also reinforced the relevance of joint bleeds in all aspects of HRQoL in haemophilic patients. The use of prophylactic factor concentrates and multidisciplinary treatments could contribute to improve the quality of life in haemophilia.

Individualized prophylaxis for optimizing hemophilia care: can we apply this to both developed and developing nations?

Prophylaxis is considered optimal care for hemophilia patients to prevent bleeding and to preserve joint function thereby improving quality of life (QoL). The evidence for prophylaxis is irrefutable and is the standard of care in developed nations. Prophylaxis can be further individualized to improve outcomes and cost effectiveness. Individualization is best accomplished taking into account the bleeding phenotype, physical activity/lifestyle, joint status, and pharmacokinetic handling of specific clotting factor concentrates, all of which vary among individuals. Patient acceptance should also be considered. Assessment tools (e.g. joint status imaging and function studies/scores, QoL) for determining and monitoring risk factors and outcome, as well as population PK profiling have been developed to assist the individualization process. The determinants of optimal prophylaxis include (1) factor dose/dosing frequency, hence, cost/affordability (2) bleeding triggers (physical activity/lifestyle, chronic arthropathy and synovitis) and (3) bleeding rates. Altering one determinant results in adjustment of the other two. Thus, the trough level to protect from spontaneous bleeding can be increased in patients who have greater bleeding risks; and prophylaxis to achieve zero joint bleeds is achievable through optimal individualization. Prophylaxis in economically constrained nations is limited by the ill-affordability of clotting factor concentrates. However, at least 5 studies on children and adults from Thailand, China and India have shown superiority of low dose (~5–10 IU kg⁻¹ 2-3× per week) prophylaxis over episodic treatment in terms of bleed reduction, and quality of life, with improved physical activity, independent functioning, school attendance and community participation. In these nations, the prophylaxis goals should be for improved QoL rather than “zero bleeds” and perfect joints. Prophylaxis can still be individualized to affordability. Higher protective trough level can be achieved by using smaller doses given more frequently without an increase in consumption/cost. The bleeding trigger can also be down-regulated by avoiding unnecessary injury, and by engaging in judicious strengthening exercises appropriate to the joint status to improve balance and joint stabilization. Central to the success of prophylaxis are clinics with comprehensive care that provide the necessary professional expertise, support, and counseling, to educate patients, families, and other healthcare professionals, and to support research for improved hemophilia care.

Nonacog beta pegol in previously treated children with hemophilia B: results from an international open-label phase 3 trial

Essentials Nonacog beta pegol is a recombinant glycoPEGylated factor IX with an extended half-life. This phase 3 trial investigated its safety/efficacy in previously treated hemophilia B boys ≤ 12 years. A 40 IU kg(-1) dose provided effective once-weekly prophylaxis and hemostasis when used to treat bleeds. Nonacog beta pegol was well tolerated in previously treated boys ≤ 12 years with hemophilia B.

SUMMARY

Background Nonacog beta pegol is a recombinant glycoPEGylated factor IX with an extended half-life, developed to improve care for patients with hemophilia B. Objectives To investigate the safety, efficacy and pharmacokinetics of nonacog beta pegol for the prophylaxis and treatment of bleeds in previously treated children with hemophilia B. Patients/Methods This phase 3 trial, paradigm(™) 5, enrolled and treated 25 children (aged ≤ 12 years) with hemophilia B (FIX ≤ 2%). Patients were stratified by age (0-6 years and 7-12 years), and received once-weekly prophylaxis with 40 IU kg(-1) nonacog beta pegol for 50 exposure days. Results No patient developed inhibitors, and no safety concerns were identified. Forty-two bleeds in 15 patients were reported to have been treated; the overall success rate was 92.9%, and most bleeds (85.7%) resolved after one dose. The median annualized bleeding rates (ABRs; bleeds per patient per year) were 1.0 in the total population, 0.0 in the 0-6-year group, and 2.0 in the 7-12-year group; the estimated mean ABRs were 1.44 in the total population, 0.87 in the 0-6-year group, and 1.88 in the 7-12-year group. For 22 patients who had previously been receiving prophylaxis, the estimated mean ABR was 1.38 versus a historical ABR of 2.51. Estimated mean steady-state FIX trough levels were 0.153 IU mL(-1) (0-6 years) and 0.190 IU mL(-1) (7-12 years). Conclusion Nonacog beta pegol was well tolerated in previously treated children with hemophilia B; a 40 IU kg(-1) dose provided effective once-weekly prophylaxis and hemostasis when bleeds were treated.

The potential correlation between patient-reported symptoms and the use of additional haemostatic medication for joint bleeding in haemophilia patients with inhibitors: a post hoc exploratory analysis of recombinant activated factor VII data from the ADEPT2 trial

: Haemophilia treatment guidelines advocate early home-based treatment of acute bleeds. In the ADEPT2 trial, data were collected on the home treatment of bleeds with recombinant activated factor VII (rFVIIa) in haemophilia patients with inhibitors and self-reported bleeding-related symptoms. A total of 93% of all bleeds, and 91.5% of joint bleeds, were treated successfully with one to three doses of 90 μg/kg rFVIIa. However, some patients self-administered additional haemostatic medication (AHM) up to 48 h after the first rFVIIa treatment. The aim of this trial was to investigate the relationship between patient-reported symptoms, time to treatment initiation, and the use of AHM. A post hoc analysis was conducted on 177 joint bleeds and the patient-reported categorical symptoms of pain, swelling, mobility, tingling, and warmth, and the pain visual analogue scale (VAS) score. Analyses were descriptive and used logistic regression modelling. Complete symptom data were available for 141, 136, and 129 joint bleeds at 0 or 1, 3, and 6 h, respectively. Pain and pain VAS assessments were the best predictors of AHM use. Patients who self-administered AHM had higher mean pain VAS scores at each time point; both pain and pain VAS scores declined over time. Time to treatment initiation was an independent predictor for AHM use. Higher initial pain scores and longer time to treatment were the best predictors for administration of AHM. The observation that some patients chose to self-infuse in the face of declining levels of pain warrants further study to better understand the reasons behind patient decision-making.

Improvement in health-related quality of life in patients with haemophilia B treated with nonacog beta pegol, a new extended half-life recombinant FIX product

INTRODUCTION

Health-related quality of life (HRQoL) of individuals with haemophilia has greatly improved with the use of factor replacement and routine prophylaxis.

AIM

To explore the HRQoL of individuals with haemophilia B treated with nonacog beta pegol, an extended half-life recombinant factor IX, in a single-blind, randomized multinational phase III pivotal trial (paradigm(™) 2) and its open-label extension (paradigm(™) 4).

METHODS

In the pivotal trial, adolescents and adults with haemophilia B were allocated to 28-week on-demand treatment or randomized to 52 weeks of prophylaxis with 10 or 40 IU kg(-1) nonacog beta pegol administered every seven days. In the extension trial, patients could continue on the same treatment or switch to the alternate dosing regimen at any time. HRQoL was assessed with the HAEMO-QOL/HAEM-A-QOL age-specific questionnaires and the EQ-5D.

RESULTS

In the pivotal trial, adults receiving 40 IU kg(-1) prophylaxis reported significant improvements in the 'HAEM-A-QOL Total' score (-6.4 ± 8.5, P = 0.017) and in 'Sport' (-15.3 ± 8.5, P = 0.020), 'Feeling' (-15.2 ± 18.3, P = 0.010) and 'Partnership' (-9.6 ± 15.5, P = 0.046) domain scores; no significant improvements were seen in the other arms. At the pivotal trial end, fewer patients reported problems in the EQ-5D 'Mobility' and 'Pain/Discomfort' dimensions, in particular those receiving prophylaxis. In the extension trial, adult patients switching from 10 to 40 IU kg(-1) prophylaxis showed significant improvements in 'HAEM-A-QOL Total' score (-12.5 ± 8.7, P = 0.016) and 'Physical health' domain (-23.1 ± 14.4, P = 0.016).

CONCLUSION

Prophylactic treatment with nonacog beta pegol 40 IU kg(-1) once weekly leads to HRQoL benefits in individuals with haemophilia B; this might be related to fewer bleeding episodes and higher FIX activity levels.

An innovative outcome-based care and procurement model of hemophilia management

Hemophilia is a rare bleeding disorder associated with spontaneous and post-traumatic bleeding. Each hemophilia patient requires a personalized approach to episodic or prophylactic treatment, but self-management can be challenging for patients, and avoidable bleeding may occur. Patient-tailored care may provide more effective prevention of bleeding, which in turn, may decrease the likelihood of arthropathy and associated chronic pain, missed time from school or work, and progressive loss of mobility. A strategy is presented here aiming to reduce or eliminate bleeding altogether through a holistic approach based on individual patient characteristics. In an environment of budget constraints, this approach would link procurement to patient outcome, adding incentives for all stakeholders to strive for optimal care and, ultimately, a bleed-free world.

Beyond stopping the bleed: short-term episodic prophylaxis with recombinant activated factor FVII in haemophilia patients with inhibitors

Preventing haemarthroses and arthropathy is a major challenge in patients with haemophilia and inhibitors, as treatment options are limited. One potential strategy is short-term episodic prophylaxis, which extends bypassing agent therapy beyond the resolution of bleeding to include the post-bleed inflammatory phase. At the 13^th Zürich Haemophilia Forum, an expert panel reviewed the rationale behind this strategy, explored its current use with recombinant activated factor VII (rFVIIa) and considered treatment monitoring and optimisation. Two protocols are currently used for short-term episodic prophylaxis, both of which stipulate on-demand rFVIIa until resolution of bleeding, followed by daily dosing for ≥3 days to prevent re-bleeds. Short-term episodic prophylaxis should be individualised to optimise outcomes, perhaps through early treatment initiation or by combining rFVIIa with other treatments (e.g. factor VIII, tranexamic acid). Encouraging treatment compliance can also improve outcomes. Additionally, there is a need to develop objective clinical outcome measures, biomarkers and imaging protocols that can monitor treatment outcomes and joint disease in patients with inhibitors. A proactive approach incorporating a systematic package of care is needed. Currently, short-term episodic prophylaxis with rFVIIa may be an alternative treatment option to on-demand treatment for patients with inhibitors.

Health economic models in hemophilia A and utility assumptions from a clinician's perspective

BACKGROUND

The clinical benefits of prophylaxis in patients with hemophilia are well-established and include the following: reduced bleeding episodes, prevention of joint damage, decreased inhibitor development, and improved health-related quality of life. However, the cost-effectiveness of prophylaxis is still not clear.

PROCEDURES

We reviewed the published hemophilia prophylaxis economic models focusing on utility assumptions.

RESULTS

We found six cost-utility studies that compared prophylaxis and on-demand regimens. These studies reported remarkably different results, using utility values based on different assumptions and data sources.

CONCLUSIONS

We suggest that cooperation among key stakeholders (clinicians, patient organizations and health-care decision makers) as a means of collecting evidence-based and experiential data to represent both the utility and the quality of life changes for patients with Hemophilia A who are treated with prophylaxis or receive on-demand treatments may represent a winning strategy with which to resolve the outstanding issues related to health technology assessments in the care of patients with hemophilia.

Classification and regression tree analysis vs. multivariable linear and logistic regression methods as statistical tools for studying haemophilia

INTRODUCTION

Haemophilia is a rare genetic haemorrhagic disease characterized by partial or complete deficiency of coagulation factor VIII, for haemophilia A, or IX, for haemophilia B. As in any other medical research domain, the field of haemophilia research is increasingly concerned with finding factors associated with binary or continuous outcomes through multivariable models. Traditional models include multiple logistic regressions, for binary outcomes, and multiple linear regressions for continuous outcomes. Yet these regression models are at times difficult to implement, especially for non-statisticians, and can be difficult to interpret.

AIMS

The present paper sought to didactically explain how, why, and when to use classification and regression tree (CART) analysis for haemophilia research.

MATERIALS & METHODS

The CART method is non-parametric and non-linear, based on the repeated partitioning of a sample into subgroups based on a certain criterion. Breiman developed this method in 1984. Classification trees (CTs) are used to analyse categorical outcomes and regression trees (RTs) to analyse continuous ones.

RESULTS

The CART methodology has become increasingly popular in the medical field, yet only a few examples of studies using this methodology specifically in haemophilia have to date been published. Two examples using CART analysis and previously published in this field are didactically explained in details.

CONCLUSION

There is increasing interest in using CART analysis in the health domain, primarily due to its ease of implementation, use, and interpretation, thus facilitating medical decision-making. This method should be promoted for analysing continuous or categorical outcomes in haemophilia, when applicable.

Rapid rFVIIa enhanced on-demand dosing in haemophilia inhibitor patients

Recombinant factor VII activated (rFVIIa) is a bypassing agent widely used in haemophilia A and B patients with antibodies against coagulation factors VIII or IX. When used according to the correct doses, rFVIIa may control bleeding, subclinical bleeding and rebleeding, avoiding the effect of neutralising inhibitors. Because of the fast action of the rFVIIa, haemostasis occurs promptly and enables a fast bleeding control with on-demand treatment in home or in surgical setting. Rapidity is also a distinguishing feature in preparation and injection of rFVIIa to cope the restraining times of busy patients and parents. The effective haemostatic activity of rFVIIa enables a sustained bleeding control, which is implemented with every other day (eod) administration and suited for enhanced on-demand therapy and short-term repeated infusions use of rFVIIa to prevent microhaemorrhages or rebleeding. Comprehensive appreciation of these pharmacological and pharmacodynamic' characteristics will likely be a further stimulus to the wider enhanced on-demand use of rFVIIa.

Switching to recombinant factor IX Fc fusion protein prophylaxis results in fewer infusions, decreased factor IX consumption and lower bleeding rates

In the phase 3 B-LONG [Recombinant Factor IX Fc Fusion Protein (rFIXFc) in Subjects with Haemophilia B] study, rFIXFc dosed every 1-2 weeks was safe and efficacious in previously treated subjects with haemophilia B. To date, there are no evaluations of transitioning from conventional to long-acting factor IX (FIX) prophylaxis. This post-hoc analysis of B-LONG subjects compared prophylaxis with other FIX products and rFIXFc. Pre- and on-study data were analysed to assess dosing regimen, weekly FIX consumption and annualized bleeding rates (ABRs). Population pharmacokinetics models were used to generate FIX activity profiles with rFIXFc and recombinant FIX prophylaxis. Thirty-nine subjects, previously treated prophylactically, were evaluated. Prior to study, most subjects (69·2%) received twice-weekly FIX infusions; on study, subjects infused rFIXFc once every 1-2 weeks with c. 30-50% reductions in weekly consumption. On-study estimated mean ABRs were lower than pre-study estimated mean ABRs. Models predicted that rFIXFc administered 50 iu/kg weekly and 100 iu/kg every 10 d would maintain steady-state FIX trough levels ≥1 iu/dl in 95·4% and 89·2% of subjects, respectively. These results indicate that patients receiving rFIXFc prophylaxis can markedly reduce infusion frequency and FIX consumption, have a greater likelihood of maintaining FIX activity >1 iu/dl and experience fewer bleeding episodes compared with prior FIX prophylaxis.

Recombinant factor IX (BAX326) in previously treated paediatric patients with haemophilia B: a prospective clinical trial

A newly developed recombinant factor IX (BAX326(1) ) was investigated for prophylactic use in paediatric patients aged <12 years with severe (FIX level <1%) or moderately severe (FIX level 1-2%) haemophilia B. The aim of this prospective clinical trial was to assess the safety, haemostatic efficacy and pharmacokinetic profile of BAX326 in previously treated paediatric patients. BAX326 was administered as prophylaxis twice a week for a period of 6 months, and on demand for treatment of bleeds. Safety was assessed by the occurrence of related AEs, thrombotic events and immunologic assessments. Efficacy was evaluated by annualized bleeding rate (ABR), and by treatment response rating (excellent, good, fair, none). PK was assessed over 72 h. None of the 23 treated paediatric subjects had treatment-related SAEs or AEs. There were no thrombotic events, inhibitory or specific binding antibodies against FIX, rFurin or CHO protein. Twenty-six bleeds (19 non-joint vs. 7 joint bleeds) occurred (mean ABR 2.7 ± 3.14, median 2.0), of which 23 were injury-related. Twenty subjects (87%) did not experience any bleeds of spontaneous aetiology. Haemostatic efficacy of BAX326 was excellent or good for >96% of bleeds (100% of minor, 88.9% of moderate and 100% of major bleeds); the majority (88.5%) resolved after 1-2 infusions. Longer T1/2 and lower IR were observed in younger children (<6 years) compared to those aged 6 to 12 years. BAX326 administered as prophylactic treatment as well as for controlling bleeds is efficacious and safe in paediatric patients aged <12 years with haemophilia B.

BAX326 (RIXUBIS): a novel recombinant factor IX for the control and prevention of bleeding episodes in adults and children with hemophilia B

Hemophilia B management has improved considerably since the introduction of high-purity plasma-derived factor IX (pdFIX) products in the early 1990s. Recombinant FIX (rFIX) was introduced more recently and has potential safety advantages over the older blood-based products. Until recently, only one such product, nonacog alfa (BeneFIX(®), Pfizer, Inc.), has been available. However, a new rFIX product, BAX326 (RIXUBIS, Baxter Healthcare Corp.), has now been approved by the US Food and Drug Administration. BAX326 undergoes rigorous virus elimination and purification steps during manufacture, and has low activated FIX activity, which confers low thrombogenic potential in humans. Preclinical studies showed promising pharmacokinetic and safety profiles, and these early findings have since been expanded in a series of prospective, multicenter, clinical studies. Foremost among these is a pivotal phase I/III study of BAX326 and its use in routine prophylaxis or on-demand treatment in patients aged 12-65 years with severe (FIX level <1%) or moderately severe (FIX level ≤2%) hemophilia B. This study confirmed the pharmacokinetic equivalence of BAX326 and nonacog alfa, and showed a significant reduction in annualized bleeding rate with BAX326 prophylaxis compared with on-demand treatment (79% versus historic controls; p < 0.001). The hemostatic efficacy of BAX326 was rated as 'excellent' or 'good' in 96% of bleeds. BAX326 was also associated with statistically significant and clinically meaningful improvements in physical health-related quality of life. Results are similarly encouraging in a pediatric study in children aged up to 12 years and in a study in hemophilia B patients undergoing surgery. A further study showed safe transition, with no inhibitor formation in any patient, from treatment with a pdFIX product to BAX326. Overall, the safety profile of BAX326 in clinical trials has been strong, with no inhibitor or specific antibody formation, thrombosis, or treatment-related serious adverse events or anaphylaxis.