[Haemophilia B therapy: impact of the reimbursability of a long-acting recombinant factor on pharmaceutical expenditure in Italy]. / Terapia dell'emofilia B: impatto dell'ammissione alla rimborsabilità di un fattore ricombinante long-acting sulla spesa farmaceutica in Italia.

OBJECTIVES: to assess the variability in expenditure compared to 2022 assuming different rates of shifting of therapy days from current active ingredients used for the treatment of haemophilia B to nonacog beta pegolDesign: descriptive cross-sectional study. SETTING AND PARTICIPANTS: consumption in the year 2022 (data source: Medicines Utilisation Monitoring Centre, Italian Medicines Agency) of all medicinal products available in Italy containing coagulation factor IX. MAIN OUTCOMES MEASURES: for each active ingredient, the total number of therapy days and the variability in expenditure compared to 2022 were estimated on the basis of a switch of therapy days, between 5% and 20%, to nonacog beta pegol. RESULTS: on the basis of considered scenarios, the analysis shows that the total annual expenditure for clotting factors used in the treatment of haemophilia B could remain at most unchanged or reduced. Particularly, the extent of the reduction in spending could vary from 0.11% to 2.26%. This trend would be in contrast to the stable increase seen in recent years, particularly in 2022. CONCLUSIONS: this predictive spending assessment may be useful in evaluating the economic impact from new treatment options, such as etranacogene dezaparvovec gene therapy already approved by the European Medicines Agency and the Food and Drug Administration, and to improve pharmaceutical governance.

Analysis of long-term clinical and cost impact of etranacogene dezaparvovec for the treatment of hemophilia B population in the United States.

INTRODUCTION: Etranacogene dezaparvovec (EDZ), Hemgenix, is a gene therapy recently approved for people with hemophilia B (PwHB). OBJECTIVE: To estimate long-term clinical impact and cost of EDZ in the United States (US). METHODS: A decision-analytic model was developed to evaluate the long-term impact of introducing EDZ for PwHB over a 20-year time horizon. Factor IX (FIX) prophylaxis comparator was a weighted average of different FIX prophylaxis regimens based on US market share data. We compared a scenario in which EDZ is introduced in the US versus a scenario without EDZ. Clinical inputs (annualized FIX-treated bleed rate; adverse event rates) were obtained from HOPE-B phase 3 trial. EDZ durability input was sourced from an analysis predicting long-term FIX activity with EDZ. EDZ one-time price was assumed at $3.5 million. Other medical costs, including FIX prophylaxis, disease monitoring, bleed management, and adverse events were from literature. The model estimated annual and cumulative costs, treated bleeds, and joint procedures over 20 years from EDZ introduction. RESULTS: Approximately 596 PwHB were eligible for EDZ. EDZ uptake was estimated to avert 11,282 bleeds and 64 joint procedures over 20 years. Although adopting EDZ resulted in an annual excess cost over years 1-5 (mean: $53 million annually, total $265 million), annual cost savings were achieved beginning in year 6 (mean: $172 million annually; total $2.58 billion in years 6-20). The total cumulative 20-year cost savings was $2.32 billion, with cumulative cost savings beginning in year 8. CONCLUSION: Introducing EDZ to treat PwHB is expected to result in cost savings and patient benefit over 20 years. Initiating PwHB on EDZ sooner can produce greater and earlier savings and additional bleeds avoided. These results may be a conservative estimate of the full value of EDZ, as PwHB would continue to accrue savings beyond 20 years.

This analysis assessed the long-term clinical and financial impact of introducing EDZ in the United States of America for people with severe or moderately severe hemophilia B. A decision-analytic model was developed comparing a scenario with EDZ and one without EDZ over 20 years. Introducing EDZ would avert 11,292 bleeds and 64 joint procedures over 20 years and would achieve cumulative cost savings in year 8, with a total cumulative 20-year cost saving of $2.32 billion.

Concurrent congenital hemophilia B and acquired hemophilia A: a unique case report.

Congenital hemophilia B is a rare X-linked recessive bleeding disorder caused by factor IX deficiency. Acquired hemophilia A is a rare, acquired bleeding disorder that presents with new-onset bleeding, especially in older adults, due to the development of auto-antibodies against factor VIII (FVIII). This case report presents the medical management of a patient with congenital hemophilia B and acquired hemophilia A. We highlight the limitations of maintaining factor levels with factor replacement therapy alone, particularly in hemophilia patients who have developed factor inhibitors. In addition, we draw attention to the need for dose escalation, the cost, and the need for immune-tolerance induction therapy. This case illustrates that when the current diagnosis does not explain the full clinical picture and laboratory data are inadequate, it is important to continue to seek alternative diagnoses and cost-effective treatment.

Bleeds and resource use in hemophilia B: retrospective observational study.

OBJECTIVES: To describe people with hemophilia B (PWHB) in the US who experience bleeds despite factor replacement therapy and to quantify the associated burden from the third-party payer perspective. STUDY DESIGN: Observational study of adult male PWHB treated with factor IX replacement therapy identified from the PharMetrics Plus claims data from 2010 to 2019. METHODS: Patients with medically recorded bleeds (MRBs) were identified using diagnostic codes. Rates and rate ratios of inpatient admissions, emergency department (ED) visits, and outpatient visits among PWHB with and without MRBs were estimated. The presence of comorbidities was identified using diagnostic codes, and the analysis was stratified by age group. RESULTS: There were 345 PWHB with MRBs and 252 without MRBs. More than half of PWHB with MRBs (56.8%) had 1 or more comorbidity vs 39.3% of PWHB without MRBs. The prevalence of anxiety and depression was high in PWHB, regardless of bleed status and age group, whereas the prevalence of other comorbidities increased with age group. The rate of all-cause inpatient admissions for PWHB with MRBs was 14.8 per 100 person-years (95% CI, 12.8-17.1), 2.5 times higher than for PWHB without MRBs. The rate of all-cause ED visits for PWHB with MRBs was 67.6 per 100 person-years (95% CI, 63.2-72.3), 2.7 times higher than for those without MRBs. CONCLUSIONS: This study reports significant resource use and clinical burden among PWHB who seek medical care. PWHB with MRBs had considerable all-cause resource use compared with PWHB without MRBs. The prevalence of mental illness was consistently high across all age groups.

Cost-Effectiveness of Recombinant Factor IX Fc Prophylaxis and Recombinant Factor IX On-Demand Treatment in Patients with Haemophilia B Without Inhibitors.

INTRODUCTION: Recombinant factor IX (rFIX) and recombinant FIX Fc fusion protein (rFIXFc) are standard half-life and extended half-life FIX replacement therapies, respectively, and represent established treatment options indicated for adults and children with haemophilia B. These FIX replacement therapies can be administered as prophylaxis (to prevent bleeding) or 'on-demand' (to stop bleeding). This analysis aimed to estimate the cost-effectiveness of once-weekly prophylaxis with rFIXFc versus on-demand treatment with rFIX in patients with haemophilia B without inhibitors in the Italian healthcare setting. METHODS: A Markov model was developed to assess a hypothetical cohort of adolescent or adult male patients (≥ 12 years) with haemophilia B (FIX level of ≤ 2 IU/dL) without inhibitors. Model inputs were derived from the pivotal phase 3 clinical studies for rFIXFc and rFIX, published literature and assumptions when published data were unavailable. The model employed a lifelong time horizon with 6-monthly transitions between health states, and it estimated total costs, total quality-adjusted life years (QALYs), number of bleeds, number of surgeries and incremental cost-effectiveness ratio. RESULTS: rFIXFc prophylaxis was associated with lower total costs per patient (€5,308,625 versus €6,564,510) and greater total QALYs per patient (15.936 versus 11.943) compared with rFIX on-demand; rFIXFc prophylaxis was therefore the dominant treatment strategy. The model also demonstrated that rFIXFc prophylaxis was associated with fewer incremental bleeds (- 682.29) and surgeries (- 0.39) compared with rFIX on-demand. CONCLUSIONS: rFIXFc prophylaxis provides improved health outcomes and lower costs, and represents a cost-effective treatment option compared with rFIX on-demand for adolescent and adult male patients with haemophilia B. This comparative assessment of cost-effectiveness should help to inform both clinicians and healthcare policy makers when making treatment decisions for patients with haemophilia B.

Hemophilia B and gene therapy: a new chapter with etranacogene dezaparvovec.

ABSTRACT: The US Food and Drug Administration (FDA)'s authorization of etranacogene dezaparvovec (Hemgenix) is a significant milestone, constituting not only the first FDA approval of a gene therapy for hemophilia but also the first approval of a liver-targeted adeno-associated virus vector gene therapy. This review summarizes the nonclinical studies and clinical development that supported regulatory clearance. Similar to other gene therapies for single gene disorders, both the short-term safety and the phenotypic improvement were unequivocal, justifying the modest-sized safety and efficacy database, which included 57 participants across the phase 2b (3 participants) and phase 3 (54 participants) studies. The most common adverse reactions included liver enzyme elevation, headache, flu-like symptoms, infusion-related reactions, creatine kinase elevation, malaise, and fatigue; these were mostly transient. One participant had hepatocellular carcinoma on a study-mandated liver ultrasound conducted 1 year after vector infusion; molecular analysis of the resected tumor showed no evidence of vector-related insertional mutagenesis as the etiology. A remarkable 96% of participants in the phase 3 trial were able to stop factor IX (FIX) prophylaxis, with the study demonstrating noninferiority to FIX prophylaxis in terms of the primary end point, annualized bleeding rate. Key secondary end points such as the annualized infusion rate, which declined by 97%, and the plasma FIX activity level at 18 months after infusion, with least squares mean increase of 34.3 percentage points compared with baseline, were both clinically and statistically significant. The FDA's landmark approval of Hemgenix as a pioneering treatment for hemophilia stands on the shoulders of >20 years of gene therapy clinical research and heralds a promising future for genomic medicines.

Haemophilia in the era of novel therapies: Where do inhibitors feature in the new landscape?

INTRODUCTION: The advent of therapeutic recombinant factor VIII (FVIII) and factor IX (FIX) protein infusions revolutionized the care of persons with haemophilia in the 1990s. It kicked off an era with the increasing use of prophylactic factor infusions for patients and transformed conversations around the ideal trough activity levels as well as the ultimate goals in tailored, individualized care. Our knowledge surrounding the immunologic basis of inhibitor development and treatment derives from a time when patients were receiving frequent factor infusions and focused on immune tolerance induction following inhibitor development. DISCUSSION: More recently, care was revolutionized again in haemophilia A with the approval of emicizumab, a bispecific antibody mimicking activated FVIII function, to prevent bleeding. The use of emicizumab prophylaxis has resulted in a significantly slower accumulation of factor exposure days and continued effective prophylaxis in the case of inhibitor development. While emicizumab is effective at reducing the frequency of bleeding events in patients with haemophilia A, management of breakthrough bleeds, trauma, and surgeries still requires additional treatment. Ensuring that FVIII is a therapeutic option, particularly for life-threatening bleeding events and major surgeries is critical to optimizing the care of persons with haemophilia A. Other novel non-factor concentrate therapies, including rebalancing agents, will dramatically change the landscape for persons with haemophilia B with inhibitors. CONCLUSION: This review discusses the changing landscape regarding the timing of inhibitor development and management strategies after inhibitor development, stressing the importance of education across the community to continue to vigilantly monitor for inhibitors and be prepared to treat persons with inhibitors.

Effect of etranacogene dezaparvovec on quality of life for severe and moderately severe haemophilia B participants: Results from the phase III HOPE-B trial 2 years after gene therapy.

INTRODUCTION: For people with haemophilia B (PwHB), bleeding may occur despite prophylaxis, negatively affecting health-related quality of life (HRQoL). The pivotal phase 3 HOPE-B trial investigating the adeno-associated virus gene transfer product, etranacogene dezaparvovec (EDZ), demonstrated sustained factor IX (FIX) activity and bleed protection in PwHB with baseline FIX levels ≤2%. AIM: Assess how EDZ affects HRQoL in HOPE-B trial participants. METHODS: HRQoL was evaluated using generic and disease-specific patient reported outcomes (PROs) including the EQ-5D-5L and the Hem-A-QoL questionnaires. Mean domain and total scores were compared 6 months pre- and the first 2 years post-EDZ administration using repeated measures linear mixed models. The percentage of participants with minimal clinically important improvements in HRQoL was also evaluated. RESULTS: Two years post-EDZ, there were nominally significant increases in the least squares (LS) mean score for the EQ-5D-5L Index Value (.04; p = .0129), reflecting better HRQoL. Nominally significant decreases in the LS mean scores, reflecting better HRQoL, were also found for the Hem-A-QoL total score (-6.0; p < .0001) and the Treatment (-13.94; p < .0001), Feelings (-9.01; p < .0001), Future (-6.45; p = .0004) and Work/School (-5.21; p = .0098) domains. The percentage of participants with ≥15-point improvement ranged from 45.83% (95% CI: 31.37%, 60.83%) for Treatment to 13.89% (95% CI: 4.67%, 29.50%) for Family Planning. Results were similar for Year 1. CONCLUSION: In conclusion, gene therapy with EDZ improved HRQoL in the first and second years in several Hem-A-QoL domains, including Treatment, Feelings, Work/School and Future domains, whereas improvement in other aspects of HRQoL were not demonstrated.

Prophylactic Treatment of Children with Hemophilia in Sweden.

Hemophilia A/B are caused by deficiency or lack of coagulation factors VIII (FVIII) or factor IX (FIX), respectively, in plasma. A person with hemophilia develops bleeding in the joints and muscles at an early age, which, if left untreated, leads to early arthropathy. Preventive treatment can be achieved by regular (prophylactic) administration of FVIII/FIX. In 1958, this was implemented on a small scale in Sweden with FVIII in patients with severe hemophilia A, and in those with hemophilia B in 1972 when FIX became available. However, there were problems with human immunodeficiency virus and hepatitis infection from contaminated blood products. In the 1990s, recombinant FVIII and FIX concentrates were introduced. The major remaining problems then were the development of inhibitors, and the need for a venous route for the injections in very young children. High-titer inhibitors were treated by immune tolerance induction according to a modified model of the original Bonn high-dose protocol. A central venous line, i.e., Port-A-Cath, has enabled early prophylaxis in many children with poor venous access and has enabled the early start of home treatment with adequate injection frequency. Scoring systems for X-rays, magnetic resonance imaging, and function of joints were developed early in Sweden and have been widely disseminated worldwide, partly with modifications. Extended half-life products with half-life increased three to five times have been developed, which can provide superior bleed protection when dosed once-weekly and can maintain therapeutic trough levels when administered less frequently. The ultimate prophylaxis therapy in the future may be gene therapy.

Multiple venous thrombosis caused by F9 gene duplication and treated with catheter-directed thrombolysis, AngioJet-assisted pharmaco-mechanical thromboectomy and manual aspiration thromboectomy.

Inferior vena cava thrombosis (IVCT) is rare. Thrombophilia is one of the important risk factors. It is also uncommon for gene mutations in F9 gene to cause thrombosis but not hemorrhage. A 35-year-old male patient was admitted to our department with left lower limb swelling without an obvious cause for 1 day. Through contrast-enhanced computed tomography and color Doppler ultrasound, he was found to have lower extremity deep vein thrombosis, IVCT and pulmonary embolism. Through whole-exome sequencing analysis, he was found to carry a 925.7 kb duplication (chrX:137939698-138865419, hg19) encompassing ATP11C , SRD5A1P1 , MCF2 , FGF13 and F9 genes. This duplication of F9 gene was not detected in his parents. Other thrombophilic genes defects were not found. The factor IX activities of this patient, his father and mother were 194, 70 and 148, respectively. He was treated with catheter-directed thrombolysis, AngioJet-assisted pharmaco-mechanical thromboectomy and manual aspiration thromboectomy. Complete recanalization of left femoral, iliac veins and inferior vena cava was achieved. F9 gene duplication is a rare mutation, which can induce multiple venous thrombosis through increasing the activity level of factor IX in plasma. IVCT is a serious type of venous thrombosis. Personalized intervention treatment plans should be developed based on the different clinical characteristics of each case to achieve a higher benefit-risk ratio.

The use of andexanet alfa vs. 4-factor prothrombin complex concentrates in the setting of life-threatening intracranial hemorrhage.

OBJECTIVE: Andexanet alfa is a targeted reversal agent for life threatening hemorrhage associated with direct acting oral anticoagulants (DOACs), but there is uncertainty regarding the benefit when compared to 4-factor prothrombin complex concentrate (4F-PCC) for this indication. We investigated the clinical outcomes and cost associated with reversal of DOACs in the setting of life-threatening intracranial hemorrhage (ICH). METHODS: A retrospective evaluation was conducted to evaluate patients with ICH in the setting of anticoagulation with DOAC from 9/1/2013 to 4/30/2020. Patients were included in the study if they received reversal with either andexanet alfa or 4F-PCC. RESULTS: Eighty-nine patients were included in the study. There was no statistically significant difference in 30-day mortality between patients who received andexanet alfa or 4F-PCC (52% vs. 35%, P  = 0.14). Radiographic stability of bleed was identified in 57% of patients receiving andexanet alfa vs. 58% of patients receiving 4F-PCC ( P  = 0.93). Median length of stay was not different between the andexanet alfa and 4F-PCC populations (7 days [IQR 6 - 12] vs. 6 days [IQR 3-12], P  = 0.66). Median cost of reversal agent was higher in patients receiving andexanet alfa compared to 4F-PCC ($15 000 [IQR 15 000-$27 000] vs. $11 650 [IQR $8567-$14 149]). CONCLUSION: Among patients with life-threatening intracranial hemorrhage in the setting of DOAC therapy, no clinical differences were observed with respect to selection of reversal agent. Prothrombin complex concentrates remain a viable alternative to reversal of DOAC therapy though multicenter, randomized, prospective studies are needed to further evaluate the role of 4F-PCC in the reversal of DOAC therapy.

AAV mediated gene therapy for haemophilia B: From the early attempts to modern trials.

Early gene therapy clinical trials for the treatment of Haemophilia B have been instrumental to our global understanding of gene therapy and have significantly contributed to the rapid expansion of the field. The use of adeno-associated viruses (AAVs) as vectors for gene transfer has successfully led to therapeutic expression of coagulation factor IX (FIX) in severe haemophilia B patients. Expression of FIX has remained stable following a single administration of vector for up to 8 years at levels that are clinically relevant to reduce the incidence of spontaneous bleeds and have permitted a significant change in the disease management with reduction or elimination of the need for coagulation factor concentrates. These trials have also shed light on several concerns around AAV-mediated gene transfer such as the high prevalence of pre-existing immunity against the vector capsid as well as the elevation of liver transaminases that is associated with a loss of FIX transgene expression in some patients. However, this field is advancing very rapidly with the development of increasingly more efficient strategies to overcome some of these obstacles and importantly raise the possibility of a functional cure, which has been long sought after. This review overviews the evolution of gene therapy for haemophilia B over the last two decades.

Pattern of use and clinical outcomes with rIX-FP in pediatric/adolescent patients with haemophilia B in Italy: Results from IDEAL real-world study.

OBJECTIVES: To evaluate pattern of use and clinical outcomes in pediatric/adolescent patients enrolled in the IDEAL study. METHODS: This post-hoc analysis of IDEAL retrospective-prospective observational study focused on patients <18 years, 100% on prophylaxis during the entire observation period. RESULTS: Thirteen subjects (median age 10.0 years; 61.5% ≤ 11 years) were analyzed. The infusion frequency changed from 2/week in 84.6% (N = 11) of patients with previous rFIX, to less than 1/weekly in 76.9% (N = 9) with rIX-FP and the annualized number of infusions reduced of 57% (p = .002), from a mean ± SD of 95.1 ± 22.77 to 40.4 ± 6.79, respectively. Annualized mean consumption decreased of about 56% (p = .001), from 3748.4 ± 1155.40 IU/kg with previous rFIX, to 1656.8 ± 456.63 IU/kg of rIX-FP. Mean FIX trough level changed from 3.0% ± 1.98% to 10.92% ± 3.6%. Low mean Annualized Bleeding Rate was maintained across all prophylaxis regimens (0.8 ± 1.69 vs. 0.3 ± 0.89) and zero bleeding patients moved from 69.2% (N = 9) with previous rFIX to 84.6% (N = 11) with rIX-FP (p = .63). Two adverse events, none related to rIX-FP, occurred in two patients. No inhibitors development was reported. CONCLUSIONS: The results in this pediatric/adolescent subgroup support rIX-FP prophylaxis may reduce infusion frequency, while providing high FIX trough levels, stable annualized bleeding rate and a good safety profile.

A new population pharmacokinetic model for recombinant factor IX-Fc fusion concentrate including young children with haemophilia B.

AIMS: Recombinant factor IX Fc fusion protein (rFIX-Fc) is an extended half-life factor concentrate administered to haemophilia B patients. So far, a population pharmacokinetic (PK) model has only been published for patients aged ≥12 years. The aim was to externally evaluate the predictive performance of the published rFIX-Fc population PK model for patients of all ages and develop a model that describes rFIX-Fc PK using real-world data. METHODS: We collected prospective and retrospective data from patients with haemophilia B treated with rFIX-Fc and included in the OPTI-CLOT TARGET study (NTR7523) or United Kindom (UK)-EHL Outcomes Registry (NCT02938156). Predictive performance was assessed by comparing predicted with observed FIX activity levels. A new population PK model was constructed using nonlinear mixed-effects modelling. RESULTS: Real-world data were obtained from 37 patients (median age: 16 years, range 2-71) of whom 14 were aged <12 years. Observed FIX activity levels were significantly higher than levels predicted using the published model, with a median prediction error of -48.8%. The new model showed a lower median prediction error (3.4%) and better described rFIX-Fc PK, especially for children aged <12 years. In the new model, an increase in age was correlated with a decrease in clearance (P < .01). CONCLUSIONS: The published population PK model significantly underpredicted FIX activity levels. The new model better describes rFIX-Fc PK, especially for children aged <12 years. This study underlines the necessity to strive for representative population PK models, thereby avoiding extrapolation outside the studied population.

High variability in Factor IX one-stage assay in samples spiked with nonacog beta pegol among different pairs of reagent/detection system.

INTRODUCTION: Haemophilia B (HB) is an X-linked hereditary bleeding disorder characterized by coagulation factor IX (FIX) deficiency. To improve the quality of life of patients and adherence to treatment, recombinant factor concentrates modified to extend their half-life have been developed, called extended half-life factors (EHL: extended half-life). Nonacog beta pegol (N9-GP) is a glycopegylated recombinant human FIX molecule that has a half-life of 93 h with a single dose and has shown a higher recovery percentage than other molecules. To diagnose and monitor the treatment of haemophiliac patients, FIX activity is determined with the one-stage clotting assay (OSA) and/or the chromogenic assay. The objective of this work, carried out in three centres, was to measure the recovery of N9-PG with 10 different activated partial thromboplastin time (APTT) reagents on three platforms, in samples spiked in vitro with N9-GP, at four different concentration levels. METHODS: It was measured the recovery of N9-GP with 10 different APTT reagents (polyphenol, ellagic acid, silice dioxide, colloidal silica as APTT activator on three platforms, in sample spiked in vitro with N9-GP. RESULTS: The results show heterogeneity in the activity of N9-GP measured by OSA with the different APTT reagents when the calibrations were performed with the specific calibrator of each coagulometer. A recovery percentage between 87% and 108% was obtained only with polyphenol and ellagic acid as activator in the three platforms evaluated. The other reagents studied overestimate or underestimate, with no clear profile. When a calibration curve was performed with a calibrator prepared from the N9-GP vial, all APTT reagents met the established recovery requirement. CONCLUSION: APTT reagents with polyphenol or ellagic acid as activator would be the only ones appropriate when using the commercially available OSA with specific calibrator to monitor patients treated with N9-GP.

The current challenges faced by people with hemophilia B.

Hemophilia B (HB) is a rare, hereditary disease caused by a defect in the gene encoding factor IX (FIX) and leads to varying degrees of coagulation deficiency. The prevailing treatment for people with HB (PWHB) is FIX replacement product. The advent of recombinant coagulation products ushered in a new era of safety, efficacy, and improved availability compared with plasma-derived products. For people with severe HB, lifelong prophylaxis with a FIX replacement product is standard of care. Development of extended half-life FIX replacement products has allowed for advancements in the care of these PWHB. Nonetheless, lifelong need for periodic dosing and complex surveillance protocols pose substantive challenges in terms of access, adherence, and healthcare resource utilization. Further, some PWHB on prophylactic regimens continue to experience breakthrough bleeds and joint damage, and subpopulations of PWHB, including women, those with mild-to-moderate HB, and those with inhibitors to FIX, experience additional unique difficulties. This review summarizes the current challenges faced by PWHB, including the unique subpopulations; identifying the need for improved awareness, personalized care strategies, and new therapeutic options for severe HB, which may provide future solutions for some of the remaining unmet needs of PWHB.

Matching-Adjusted Indirect Comparison of Recombinant Factor IX Albumin Fusion Protein Versus Recombinant Factor IX Fc Fusion Protein for Weekly Prophylactic Treatment of Hemophilia B.

INTRODUCTION: Prophylactic treatment of hemophilia B with recombinant factor IX (rFIX) molecules with enhanced pharmacokinetics including rIX-FP (albutrepenonacog alfa; Idelvion©) and rFIXFc (eftrenonacog alfa; Alprolix©) have commonly been used in the clinic. In the absence of head-to-head comparative trials, the aim of this study was to estimate the efficacy of rIX-FP versus rFIXFc using matching-adjusted indirect comparisons (MAICs). METHODS: MAIC analyses leveraged individual patient data from the PROLONG-9FP trial and published summary-level data from the B-LONG trial for subjects who received weekly prophylaxis regimens. Individual patient data were used to assign weights and balance subjects from PROLONG-9FP with subjects from B-LONG on baseline disease severity, age, prior FIX regimen, and body mass index (BMI). Six efficacy outcomes were analyzed including annualized bleeding rate (ABR), annualized spontaneous bleeding rate (AsBR), annualized joint bleeding rate (AjBR), and the proportion of subjects without bleeding events (for total, spontaneous, and joint bleeding events). RESULTS: After adjustment for baseline disease severity, age, prior FIX regimen, and BMI, rIX-FP was associated with a statistically significant decrease in AsBR (rate ratio [RR] 0.42; 95% confidence interval [CI] 0.22, 0.82; P = 0.0107), and the proportion of patients without bleeding events (odds ratio [OR] 3.24; 95% CI 1.41, 7.45; P = 0.0057), spontaneous bleeding events (OR 3.47; 95% CI 1.56, 7.73; P = 0.0023), and joint bleeding events (OR 2.41; 95% CI 1.10, 5.26; P = 0.0274) compared with rFIXFc. Prophylactic treatment with rIX-FP was also associated with a numerically lower ABR (RR 0.75; 95% CI 0.32, 1.75; P = 0.5095) and AjBR (RR 0.82; 95% CI 0.37, 1.82; P = 0.6178). CONCLUSION: The MAICs demonstrated that weekly prophylaxis treatment of severe hemophilia B with rIX-FP resulted in favorable efficacy outcomes as compared to rFIXFc. These findings suggest rIX-FP may offer improved clinical benefits over rFIXFc.

Health-related quality of life and physical activity in Nordic patients with moderate haemophilia A and B (the MoHem study).

INTRODUCTION: The impact of moderate haemophilia on health-related quality of life (HRQoL) and physical activity (PA) is not well known. In previous studies, persons with factor VIII/factor IX activity (FVIII/FIX:C) below 3 IU/dL were associated with a more severe bleeding phenotype than predicted. AIM: To explore HRQoL and PA in patients with moderate haemophilia A (MHA) and B (MHB). METHODS: A cross-sectional, multicentre study covering patients with MHA and MHB in Sweden, Finland, and Norway. HRQoL was assessed with the EuroQoL 5-Dimensions (EQ-5D) form and PA with the International Physical Activity Questionnaire among participants aged ≥15 years. RESULTS: We report on 104 patients aged 15-84 years from the MoHem study. Overall, EQ-5D utility was .85 (median) (Q1-Q3 0.73-1.0) with corresponding visual analogue scale (VAS) 80 (70-90), which were similar regardless of treatment modality, FVIII/FIX:C, and MHA or MHB. Pain and mobility were most frequently affected dimensions. Utility (r = -.54), VAS (r = -.42), and PA (r = -.32) correlated negatively with arthropathy (HJHS). Only patients aged 41-50 years displayed lower utility (p = .02) and VAS (p < .01) than the Norwegian population norm. Patients on prophylaxis aged 35-54 years reported higher PA than those treated on-demand (p = .01). CONCLUSION: Haemophilic arthropathy had negative impact on HRQoL and PA in Nordic patients with moderate haemophilia. Middle-aged patients captured lower utility and VAS than observed in the general population. Tailored prophylaxis and improved joint health may influence positively on HRQoL and PA also in moderate haemophilia.

Indirect treatment comparisons of the gene therapy etranacogene dezaparvovec versus extended half-life factor IX therapies for severe or moderately severe haemophilia B.

INTRODUCTION: Etranacogene dezaparvovec gene therapy for haemophilia B demonstrated superior efficacy at 24 months in reducing bleeds versus a ≥6-month lead-in period of prophylaxis with FIX products in the phase 3 trial, HOPE-B. In the absence of head-to-head comparisons of etranacogene dezaparvovec versus FIX products, indirect treatment comparisons (ITC) can be used. AIM: To compare the efficacy of etranacogene dezaparvovec versus rIX-FP, rFIXFc and N9-GP using ITC, and support HOPE-B results. METHODS: Data were leveraged from Phase 3 pivotal trials: HOPE-B, PROLONG-9FP, B-LONG and Paradigm 2. Annualised bleeding rates (ABR), spontaneous (AsBR) and joint (AjBR) bleeding rates, percentage of patients with no bleeds, and FIX consumption were assessed using inverse probability of treatment weighting and matching adjusted indirect comparisons. RESULTS: Etranacogene dezaparvovec demonstrated statistically significantly lower bleeding rates versus all comparators. Rate ratios for ABR, AsBR and AjBR versus rIX-FP were 0.19 (p < .0001), 0.08 (p < .0001) and 0.09 (p < .0001), respectively. Rate ratios for ABR, AsBR and AjBR versus rFIXFc were 0.14 (p < .0001), 0.13 (p = .0083) and 0.15 (p = .0111), respectively. Rate ratios for ABR and AsBR, versus N9-GP were 0.24 (p = .0231) and 0.13 (p = .0071), respectively. Etranacogene dezaparvovec demonstrated significantly higher percentage of patients with no bleeds versus rIX-FP and rFIXFc; odds ratios: 17.60 (p < .0001) and 5.65 (p = .0037), respectively. Etranacogene dezaparvovec resulted in significantly lower FIX consumption than all comparators. CONCLUSIONS: ITC suggests that etranacogene dezaparvovec offers patients with haemophilia B (≤2% of normal FIX expression) a single dose treatment that can significantly reduce bleeding rates and eliminate routine infusions associated with FIX therapies.