High adherence to prophylaxis regimens in haemophilia B patients receiving rIX-FP: Evidence from clinical trials and real-world practice

Extension of the circulatory half-life of recombinant ecallantide via albumin fusion without loss of anti-kallikrein activity

Ecallantide comprises Kunitz Domain 1 of Tissue Factor Pathway Inhibitor, mutated at seven amino acid positions to inhibit plasma kallikrein (PK). It is used to treat acute hereditary angioedema (HAE). We appended hexahistidine tags to the N- or C-terminus of recombinant Ecallantide (rEcall) and expressed and purified the resulting proteins, with or without fusion to human serum albumin (HSA), using Pichia pastoris. The inhibitory constant (Ki) of rEcall-H6 or H6-rEcall for PK was not increased by albumin fusion. When 125I-labelled rEcall proteins were injected intravenously into mice, the area under the clearance curve (AUC) was significantly increased, 3.4- and 3.6-fold, for fusion proteins H6-rEcall-HSA and HSA-rEcall-H6 versus their unfused counterparts but remained 2- to 3-fold less than that of HSA-H6. The terminal half-life of H6-rEcall-HSA and HSA-H6 did not differ, although that of HSA-rEcall-H6 was significantly shorter than either other protein. Receptor Associated Protein (RAP), a Low-density lipoprotein Receptor-related Protein (LRP1) antagonist, competed H6-rEcall-HSA clearance more effectively than intravenous immunoglobulin (IVIg), a neonatal Fc receptor (FcRn) antagonist. HSA fusion decreases rEcall clearance in vivo, but LRP1-mediated clearance remains more important than FcRn-mediated recycling for rEcall fusion proteins. The properties of H6-rEcall-HSA warrant investigation in a murine model of HAE.

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.

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.

Benefits of rIX-FP prophylaxis in patients with Haemophilia B: real-world evidence from a Spanish reference centre

Standard FIX prophylaxis for PWHB require frequent injections, which has led to the development of extended half-life products like rIX-FP (albutrepenonacog alfa) that has shown good efficacy in clinical studies. This ambispective study aims to report a real-world experience with rIX-FP in a Spanish centre with PWHB who switched from SHL-FIX or began prophylaxis with rIX-FP. Five PWHB were included in this study, Four PTP switched to rIX-FP with prophylaxis every 7 days whilst one PUP started with an every-14-days regimen. 3 PTPs extended their dosing intervals to every 14 days or every 21 days. In all PTPs, median annualized spontaneous and joint bleeding rates were maintained at 0.00 and median (range) of ABR was 0.92 (0.00-2.77) after switch to rIX-FP. Mean trough level with previous product was 3.68% (SD = 2.06), while it was 7.08% (SD = 3) with all rIX-FP dosing intervals. After switching to rIX-FP, all PTP reduced their annual infusion rate between 50 and 84% and their annual FIX consumption by 61% (59-67%). This is the first reported real-world experience with albutrepenonacog alfa in a small cohort in Spain and demonstrates good bleeding control together with a reduction of the infusion rate, factor consumption and higher through factor level than previous treatment.

Real-world experience of rIX-FP prophylaxis at dosing intervals of up to 14 days in a pediatric patient with hemophilia B during the COVID-19 pandemic

Switching to rIX-FP prophylaxis at dosing intervals of up to 14 days in a hemophilia B pediatric patient decreased treatment burden by reducing the number of administrations and hospital visits, without affecting efficacy or treatment adherence. This is particularly important in contexts of limited mobility and overloaded healthcare services.

Switching and increasing prophylaxis regimen with a genetically recombinant fusion of coagulation factor IX and albumin in haemophilia B: a case report

PURPOSE OF REVIEW

We present a case of a boy diagnosed in 2007 with severe haemophilia B [factor IX (FIX) concentration < 1%] at age of 9 months. He was initially treated with recombinant FIX concentrates, but changes in regimens were frequent due to spontaneous hemarthros. In 2013, he entered a phase III trial (NCT01662531) and received rIX-FP, IDELVION at 50 IU/kg once a week. Although the boy was safely maintained with this regimen (2015-2017), the number of hemarthros increased after he started to play football. Thus, rIX-FP regimen was modified (40 IU/kg twice/week) to optimize therapy. This modification was efficient on maintaining patient's thought levels (33%), helped during his fully incorporation at school and social life, and significantly improved synovial hypertrophy. In the last year, the boy has not suffered any bleeding episode and his joint situation improved significantly, which allowed reducing doses to weekly recommended doses.

RECENT FINDINGS

FIX replacement therapies with intravenous plasma-derived FIX (pdFIX) or standard half-life recombinant FIX (rFIX) concentrates are hampered by the relatively short terminal elimination half-life (t1/2) of these substances (around 17-34 h), resulting in the need for frequent infusions (e.g. once every 3 or 4 days) to maintain protective FIX levels. In the past years, the first genetically recombinant fusion of rFIX with another protein - a recombinant human albumin - was developed (albutrepenonacog-alfa or rIX-FP; IDELVION) as a strategy to extend the t1/2 of rFIX-FP (around 95 h).

SUMMARY

We provide information about the difficult management of a patient with a major bleeding haemorrhagic phenotype, which caused serious limitations in the patient's daily life, impacting his quality of life at his young age, and how the switch to IDELVION allowed the situation to improve considerably.

Switching from Sucrose-Formulated rFVIII to Octocog Alfa (BAY 81-8973) Prophylaxis Improves Bleed Outcomes in the LEOPOLD Clinical Trials

Introduction

Previous clinical trials established the efficacy and safety of sucrose-formulated recombinant factor (F) VIII (rFVIII-FS/Kogenate FS®/Helixate FS®) and octocog alfa (BAY 81-8973/Kovaltry®; LEOPOLD trials).

Aim

To report the results of a post hoc subgroup analysis assessing efficacy and safety outcomes in patients with hemophilia A who were receiving rFVIII-FS prior to enrolling into the LEOPOLD I Part B and LEOPOLD Kids Part A clinical trials and switching to octocog alfa.

Methods

LEOPOLD I Part B (NCT01029340) and LEOPOLD Kids Part A (NCT01311648) were octocog alfa Phase 3, multinational, open-label studies in patients with severe hemophilia A aged 12-65 years and ≤12 years, respectively. Annualized bleeding rate (ABR) was the efficacy endpoint for both studies. Safety endpoints included adverse events (AEs) and development of FVIII inhibitors.

Results

Of the 113 patients in both LEOPOLD trials, 40 (35.4%) patients received rFVIII-FS prophylaxis pre-study and had data available for pre-study total ABR. In LEOPOLD I Part B (n = 22, 35.5%), median (Q1; Q3) total ABR decreased from 2.5 (0.0; 9.0) pre-study to 1.0 (0.0; 6.8), and from 1.0 (0.0; 6.0) pre-study to 0.0 (0.0; 6.02) in LEOPOLD Kids Part A (n = 18, 35.3%). Octocog alfa was well tolerated, and no patients had drug-related serious AEs or inhibitors.

Conclusion

Treatment with octocog alfa prophylaxis appeared to have a favorable risk-benefit profile compared with rFVIII-FS and thus could be an effective and improved alternative strategy for individualized treatment for children, adolescent and adult patients with severe hemophilia A currently on rFVIII-FS treatment.

Clinical experience of switching patients with severe hemophilia to rVIII-SingleChain or rIX-FP

OBJECTIVE

Prophylaxis treatment is the current standard of care for patients with severe hemophilia. Factor concentrates with improved pharmacokinetics have offered more options for individualizing treatment. The treatment focus may be on increased protection, aiming for higher trough factor levels or longer dosing intervals to reduce the burden of hemophilia. Both aspects can have long-term effects on joint health. Products, such as rVIII‑SingleChain and rIX-FP have been developed to reduce the treatment burden for patients with hemophilia and optimize prophylactic efficacy. The objective of this report is to provide a summary of the clinical experience of different Hemophilia Treatment Centers in managing the switch to rVIII-SingleChain or rIX-FP in patients with hemophilia.

METHODS

This report summarizes a selection of patient cases presented at the 3rd Alliance for Coagulation Academy Meeting in October 2020. The cases from the participating centers provide examples of the clinical experience in managing patients' switch to rVIII-SingleChain and rIX‑FP, including which types of patients are suitable for switching, and practical steps in managing a switch.

RESULTS

It is important to take into consideration the physical and social fulfillment of the patient when deciding to switch to rVIII-SingleChain or rIX-FP. The physician plays an important role in the motivation of patients as they understand not only the patient's needs but the potential benefits of the new treatment.

CONCLUSION

The selected patient cases reported here demonstrate that patients may wish to switch factor products for a variety of reasons; therefore, it is critical to understand why patients switch and what they expect from switching.

IDEAL study: A real-world assessment of pattern of use and clinical outcomes with recombinant coagulation factor IX albumin fusion protein (rIX-FP) in patients with haemophilia B in Italy

INTRODUCTION

Factor IX replacement therapy is used for treatment and prophylaxis of bleeding in haemophilia B. rIX-FP is an extended half-life albumin-fusion protein, which, in clinical studies, has demonstrated prolonged dosing intervals up to 21 days for routine prophylaxis, providing therapeutic benefit.

AIMS

To describe dosing frequency and consumption (primary endpoint), efficacy and safety of rIX-FP treatment during routine clinical practice in Italy.

METHODS

Patients with moderate/severe haemophilia B on prophylaxis with rIX-FP for ≥6 months, were enrolled in this observational study from October 2017 to February 2019 and followed-up for 2 years. Descriptive analysis included prospective and retrospective data (12 months prior to switching to rIX-FP).

RESULTS

Data were collected from 59 male patients (median age 30.1 years) enrolled by 23 Italian centres. Of them, 50 were on prophylaxis during the entire observation period and completed the study. The infusion frequency changed from 2-3 times/week in 86.0% of patients with previous treatment, to less than once a week in 84.0% of patients treated with rIX-FP at the 2nd-year follow-up. The annual number of infusions decreased by about 70%, whereas the mean FIX activity trough level increased from 3.8% to 14.4% (mean > 10% in all the infusion regimens). Median Annualised Bleeding Rate of .0 was achieved across all prophylaxis regimens. Subjects with zero bleedings increased from 66.0% to 78.0% with rIX-FP.

CONCLUSION

Treatment with rIX-FP reduced infusion frequency, while providing higher FIX trough levels with substantial benefit in terms of annualised bleeding rate and a good safety profile.

Long-term prophylaxis: what are our options and how to define success?

Currently, we are at an enviable place in hemophilia treatment. Although full prophylaxis with standard half-life recombinant or plasma-derived factor concentrates has been definitively shown to be inadequate for full protection against bleeding and arthropathy, a number of novel therapies with improved hemostatic enhancement are clinically available or in promising clinical trials. In order to compare outcomes among a number of very efficacious therapies, it is necessary to have sensitive tools employed in long-term follow-up for several years for participants with no or minimal joint disease. The tool kit must be comprehensive, with outcomes of bleeding, factor level restoration or hemostatic capacity, joint structure, joint function, pain, quality of life, and patient satisfaction. This article reviews the history of prophylaxis, the promise of emerging therapies, and the sensitive tools used to assess long-term efficacy for joint structure and function.

Albumin-Fusion Recombinant FIX in the Management of People with Hemophilia B: An Evidence-Based Review

Albutrepenonacog-alfa (Idelvion®, CSL Behring) is a recombinant fusion protein in which the recombinant FIX (rFIX) links a recombinant human albumin, extending the half-life of rFIX even beyond 100 hours. In 2016, this drug was approved worldwide for the treatment of pediatric and adult persons with hemophilia B (PWH-B). Its efficacy and safety were described in the PROLONG-9FP program and subsequently confirmed in the real-world practice, even if to date there are not many manuscripts that extensively and completely deal with the use of albutrepenonacog-alfa in daily practice, also evaluating its impact on the quality of life of patients treated with this drug; this review therefore aims to analyze all the publications currently available regarding the real-world use of this extended half-life concentrate, also noting which topics need further study and research.

Investigation of the Bleeding Tendency in Sudanese Female Carriers of Hemophilia B

Background. Hemophilia (HB) is an X-linked, recessive bleeding disorder characterized by the deficiency or absence of the coagulation factor IX. Usually, females are carriers of the trait, while males are affected. FIX deficiency leads to uncontrollable bleeding events, and the severity is dependent on the levels of the clotting factor. The objective of this research was to measure the prevalence of bleeding tendency in Sudanese carriers of HB. Materials and Methods. In this cross-sectional study, 88 Sudanese carriers of HB participated. The activated partial thromboplastin time test (APTT) and FIX test were performed for each carrier. The frequencies of DNA polymorphism and FIX-linked restriction fragments BamHI, HhaI, and MnII were also assessed. The study was conducted in Khartoum, Sudan, during the period from 2015 to 2017. Results. The study showed that 55 (62.5%) HB carriers were from the Laban village in the White Nile State, and all of them were members of the Shinkheb tribe. The mean age of the study population was 26.3 years. Among the carriers, 57 (64.7%) had abnormal coagulation profiles. The mean value of the APTT level among carriers was significantly increased ( $P$ value: 0.000), while the mean concentration of the FIX levels among the carriers was significantly decreased ( $P$ value: 0.000). The study also showed a negative correlation between PTT and F assay with $P$ value of 0.000 and $R$ value of 0.578. Conclusion. The APTT is high in most carriers and the FIX assay level is low in most carriers. Most carriers had no symptoms and were not bleeding. The Shinkheb tribe is the most ethnic tribe carrying HB (62.5%). HhaII is more informative for carrier detection than others, but it is of significant value if both (MnII and HhaII) were performed in parallel. In Sudanese, BamHI was informative but MnII and HhaII were best in the mutation detection and for prenatal diagnosis.

IDELVION: A Comprehensive Review of Clinical Trial and Real-World Data

Hemophilia B is a bleeding disorder caused by a deficiency of coagulation factor IX (FIX). Treatment with FIX replacement products can increase FIX activity levels to minimize or prevent bleeding events. However, frequent dosing with standard-acting FIX products can create a high treatment burden. Long-acting products have been developed to maintain bleed protection with extended dosing intervals. Recombinant factor IX–albumin fusion protein (rIX-FP) is a long-acting product indicated for the treatment and prophylaxis of bleeding events and perioperative management in adult and pediatric patients. This review outlines data from all previously treated patients in the Prophylaxis and On-Demand Treatment using Longer Half-Life rIX-FP (PROLONG-9FP) clinical trial program and summarizes real-world data evaluating the use of rIX-FP in routine clinical practice. In the PROLONG-9FP program, rIX-FP demonstrated effective hemostasis in all patients at dose regimens of up to 21 days in patients aged ≥ 18 years and up to 14 days in patients aged < 12 years. rIX-FP has a favorable pharmacokinetic profile and an excellent safety and tolerability profile. Extended dosing intervals with rIX-FP led to high levels of adherence and reduced consumption compared with other FIX therapies. Data from real-world practice are encouraging and reflect the results of the clinical trials.

How do we optimally utilize factor concentrates in persons with hemophilia?

The current mainstay of therapy for hemophilia is to replace the deficient clotting factor with the intravenous administration of exogenous clotting factor concentrates. Prophylaxis factor replacement therapy is now considered the standard of care in both pediatric and adult patients with hemophilia with a severe phenotype to protect musculoskeletal health and improve quality of life. Heterogeneity in bleeding presentation among patients with hemophilia due to genetic, environmental, and treatment-related factors has been well described. Accordingly, the World Federation of Hemophilia recommends an individualized prophylaxis regimen that considers the factors mentioned above to meet the clinical needs of the patient, which can vary over time. This review focuses on the practical points of choosing the type of factor concentrate, dose, and interval while evaluating appropriate target trough factor levels and bleeding triggers such as level of physical activity and joint status. We also discuss the use of a pharmacokinetics assessment and its incorporation in the clinic for a tailored approach toward individualized management. Overall, adopting an individualized prophylaxis regimen leads to an optimal utilization of factor concentrates with maximum efficacy and minimum waste.

Expert opinion paper on the treatment of hemophilia B with albutrepenonacog alfa

Introduction: Current guidelines recommend prophylactic treatment of hemophilia B with the missing coagulation factor IX, either with standard half-life or extended half-life products. Extended half-life products have half-lives three to six times longer than the former, allowing a reduction in the number of weekly injections and therefore, potentially impacting on treatment adherence and quality of life. Albutrepenonacog alfa is an extended half-life fusion protein of coagulation factor IX with recombinant human albumin, indicated for both on-demand and prophylactic treatment for bleeding in patients with hemophilia B of all ages.Areas covered: The authors review the clinical and pharmacokinetic characteristics of albutrepenonacog alfa, as well as the available information regarding trough levels and real-world evidence. Given the availability of other factor IX products in the market, indirect comparisons of clinical and pharmacokinetic characteristics are presented.Expert opinion: The authors exhibit their expert opinion on which patient profiles are candidates for prophylactic treatment with albutrepenonacog alfa, and on the management of patients in terms of dosing, regimens of administration and protocols for switching the treatment.

Management of musculoskeletal complications in patients with hemophilia: literature review and expert recommendations

In people with hemophilia, hematological prophylaxis during childhood and adolescence could elude the occurrence of musculoskeletal complications (in joints and muscles) if the concentration of the defective factor is averted from decreasing under 1% of normal. Prompt management is of capital significance as the juvenile skeleton is hypersensitive to the adverse events of the disease; intense structural defects might appear rapidly. Important articular bleeds and inveterate hypertrophy of the articular synovial membrane must be treated vigorously to preclude joint degeneration (hemophilic arthropathy). At the moment that extreme joint disease is in place with intense affliction, the goal must be to reestablish activity whilst at the same time reducing the peril to the patient. Articular debridement is an efficacious surgical technique to accomplish this goal, particularly around the knee or ankle, and may be contemplated to be a backup to ankle arthrodesis or ankle or knee replacement in patients of younger age. Eventually joint replacement can commonly reestablish both articular mobility and function in an unhealthy articulation.

High adherence to prophylaxis regimens in haemophilia B patients receiving rIX-FP: Evidence from clinical trials and real-world practice

Introduction

Adherence to prophylaxis regimens is essential for bleed prevention in haemophilia but remains a challenge due to the need for frequent infusions.

Aim

To evaluate patient adherence to prophylaxis regimens with a long‐acting recombinant factor IX (rIX‐FP; IDELVION^®) in clinical studies and real‐world practice.

Methods

In two phase 3 clinical studies, patients with haemophilia B (FIX ≤2%) recorded their dose, dosing frequency and rIX‐FP consumption in an e‐diary. Adherence to prescribed prophylaxis regimens was assessed in all patients and to prescribed dose in patients ≥12 years only. Additionally, adherence to rIX‐FP prophylaxis regimens in real‐world practice was captured.

Results

In clinical studies, 94.9% (n = 56/59) of patients ≥12 years and 100% (n = 27) of paediatric patients received ≥80% of the expected number of infusions for their assigned prophylaxis schedule. Overall, mean adherence rate was 95.5% across all prophylaxis regimens in patients ≥12 years and 97.9% with a 7‐day regimen in paediatric patients. In patients ≥12 years, 85.7% (n = 54/63) were dose adherent, defined as receiving within 10% of their prescribed dose ≥80% of the time. In real‐world practice, adherence was observed in 100% (n = 14 and n = 15, respectively) of patients in two haemophilia treatment centres and 57.1% (n = 4/7) of patients in a third centre; non‐adherence (n = 3/7) was linked to insurance‐related and parental issues.

Conclusion

In clinical studies, patients with haemophilia B had high adherence rates to rIX‐FP prophylaxis regimens with a variety of dosing intervals, enabling them to achieve very low bleeding rates. High adherence may also be achievable in real‐world practice.