Surgical outcomes in patients with haemophilia A or B receiving extended half-life recombinant factor VIII and IX Fc fusion proteins: Real-world experience in the Nordic countries

Real-world usage and effectiveness of recombinant factor IX Fc in haemophilia B from the B-SURE study in France

Background

More real-world data are needed to complement existing phase III studies on the efficacy and safety of recombinant factor IX Fc fusion protein (rFIXFc) in people with haemophilia B.

Objectives

We report final data from the B-SURE study, evaluating the real-world usage and effectiveness of rFIXFc in France.

Methods

Previously treated patients (all ages/severities) received on-demand or prophylactic rFIXFc during B-SURE. Annualised bleeding rate (ABR), injection frequency (IF) and factor consumption (FC) were prospectively evaluated for patients on rFIXFc prophylaxis (primary endpoints). Six months of retrospective factor IX (FIX) data were collected for comparison; patients with ⩾3 months of treatment pre- and post-switch to rFIXFc were analysed.

Design

B-SURE was a 24-month, prospective, non-interventional, real-world study across haemophilia treatment centres in France.

Results

Ninety-one male patients enrolled across 21 centres (34% <18 years, 89% severe haemophilia B). Eighty-four patients received prophylaxis at rFIXFc initiation; mean prospective observation period was 21.5 months. Sixty-eight of 84 patients had prior FIX prophylaxis; on rFIXFc prophylaxis, these patients achieved low median ABR (1.2), IF (47.45 injections/year) and mean FC (2844 IU/kg/year). Compared with previous FIX, mean ABR was reduced by 40% (n = 63); mean IF and FC were reduced by 38.20 injections/year and 1008 IU/kg/year (n = 57). In patients with prior FIX on-demand (n = 15), mean ABR reduced by 84% on rFIXFc prophylaxis (n = 14), mean IF reduced by 2.13 injections/year and mean FC increased by 381.8 IU/kg/year (n = 15). Most physicians and patients were satisfied/highly satisfied with rFIXFc prophylaxis. rFIXFc was well tolerated with no new safety concerns.

Conclusion

Findings support the safety and effectiveness of rFIXFc, with reduced IF and FC while maintaining/improving bleed protection. Trial registration: NCT03655340.

Perioperative Hematological Outcomes of Simultaneous Double Total Joint Arthroplasty for Hemophilic Arthritis of the Hip and Knee: A Retrospective Study

BACKGROUND

Double total joint arthroplasty (TJA) can reduce repeat hospitalizations and total coagulation factors usage in hemophilic arthritis (HA) patients who have multiple joint involvement, but the risk of perioperative adverse events with double TJA must be considered.

METHODS

We reviewed 50 patients who had hemophilia A, including 26 single TJA (STJA) (13 total knee arthroplasty [TKA] and 13 total hip arthroplasty [THA]) and 24 simultaneous double TJA (Sim-DTJA) (including 10 bilateral TKAs, 10 bilateral THAs, and four patients who had simultaneous THA and TKA). Length of hospitalization, blood loss, total exogenous coagulation factor VIII (FVIII) usage, perioperative FVIII levels, perioperative activated partial thromboplastin time, perioperative transfusion rates, and postoperative complications were assessed and compared.

RESULTS

Perioperative FVIII levels and activated partial thromboplastin time were not different between Sim-DTJA and STJA. Total blood loss (1,216.0 ± 450.4 mL) and hidden blood loss (1,020.0 ± 419.9 mL) were slightly higher in Sim-DTJA than in STJA (1,062.0 ± 371.8 mL and 929.9 ± 351.6 mL, respectively) (P = 0.192, P = 0.416, respectively). The length of hospitalization between the Sim-DTJA (10.6 ± 1.8 days) and the STJA (10.4 ± 1.7 days) was not different (P = 0.802). The perioperative FVIII usage was 30,063 ± 6,466 international unit for Sim-DTJA and 26,077 ± 12,524 international unit for STJA (P = 0.008). No postoperative adverse events and prosthesis-related complications were reported in any of the patients. The two cohorts had no perioperative transfusion of erythrocyte and platelets.

CONCLUSION

In HA patients who had multiple joint involvements, Sim-DTJA can achieve clinical efficacy without significantly increasing perioperative blood loss, length of hospitalization, and postoperative complications.

Recombinant factor IX Fc for the treatment of hemophilia B

Current hemophilia B treatment guidelines recommend routine prophylaxis with factor IX (FIX) replacement products, tailored to maintain plasma activity at levels that will prevent bleeds. However, plasma FIX activity may not be the primary determinant or best indicator of hemostatic efficacy due to its extravascular distribution. FIX replacement therapy has evolved to include extended half-life (EHL) products that provide effective bleed protection when administered at intervals of 7 days or longer. rFIXFc is a recombinant fusion protein with an extended circulation time. rFIXFc has a biodistribution profile consistent with distribution into extravascular space, where it may support hemostasis at sites of vessel injury independent of circulating plasma activity levels. The safety and efficacy of rFIXFc prophylaxis is well established in adults, adolescents and children including previously untreated patients with hemophilia B, with substantial evidence from clinical trials and real-world clinical practice. This review describes the pharmacokinetic characteristics of rFIXFc, summarizes available safety and efficacy data, and evaluates the use of rFIXFc in special populations. Current hemophilia B treatment challenges, including target FIX plasma levels, perioperative use, and management of patients with comorbidities, are discussed together with the potential role of EHL products in the future treatment landscape of hemophilia B.

Comparison of one-stage and chromogenic factor VIII assays to tailor the dose of recombinant factor VIII-Fc fusion protein (rFVIIIFc, efmoroctocog alfa) in adult patients with haemophilia A: Single-centre, real-world experience of surgery

BACKGROUND

Efmoroctocog alfa (rFVIIIFc) is an extended half-life FVIII used notably in surgery for patients with haemophilia A. More information is needed of its usage in real-life.

METHODS

Adult patients with HA followed at the Lyon Comprehensive Hemophilia Care Center who underwent a surgery with rFVIIIFc were included in this retrospective analysis. The pharmacokinetics of rFVIIIFc was assessed by plasma factor VIII clotting activity (FVIII:C) using both one-stage (OSA) and chromogenic substrate (CSA) assays.

RESULTS

A total of 39 major and 31 minor surgeries were performed in 49 patients treated with rFVIIIFc. The median dose of rFVIIIFc infused before major and minor surgeries respectively was 67.5 ((interquartile range [IQR] 52.6-76.9) and 48.0 (38.5-51.8) IU/kg. For major surgeries, during the first postoperative week, the median residual FVIII:C was 78 (64.5-101.5) IU/dL with OSA and 99 (71-118) IU/dL with CSA (p < .0001). After surgery, rFVIIIFc doses were adjusted according to CSA results. This led to a significant decrease of rFVIIIFc consumption compared to what would have been proposed according to the OSA assay, without unusual bleeding or appearance of inhibitor. Considering the high price of the molecule, this was also associated with a significant cost reduction.

CONCLUSION

Dose adjustment of rFVIIIFc according to FVIII: C measured by CSA is effective, safe and well tolerated in patients with haemophilia A undergoing invasive surgery.

Development and evaluation of a bivalent vaccine based on recombinant newcastle disease virus expressing infectious bursal disease virus VP2L-CH3-CH4 in SPF chickens

Newcastle disease (ND) and infectious bursal disease (IBD) are two viral infectious diseases that are extremely damaging to the poultry industry and are widespread throughout the world. It is necessary to develop a safe and effective vaccine against IBD and ND because vaccination is an effective preventive measure. It has been discovered that recombinant proteins expressed by an expression system in which a fragment of mammalian Immunoglobulin G (IgG) Fragment crystallizable (Fc) is linked to a segment of a gene have antibody-like properties that increase the exogenous protein's serum half-life. Heavy chain constant region 3 and heavy chain constant region 4 (CH3-CH4) of Avian Immunoglobulin Y (IgY) is structurally very similar to mammalian Ig G Fc. In this study, a bivalent vaccine rClone30-VP2L-CH3-CH4-GMCSF was developed by using NDV rClone30-chGM-CSF vector to produce VP2L-CH3-CH4 fusion protein. The vaccine has been given to 14-day-old specific pathogen free (SPF) free chickens to test whether it has the potential to prevent IBD and ND. Anti-IBDV and anti-NDV antibody levels in serum were evaluated using ELISA and HI, respectively, and the contents of CD4+ T, CD8+ T, and B cells in leukocytes were determined via flow cytometry. The contents and mRNA transcription levels of four inflammatory factors, IL-1β, IL-4, IFN-γ and chGM-CSF, were detected by ELISA and real-time PCR respectively. The results showed that after vaccination with the rClone30-VP2L-CH3-CH4-GMCSF vaccine, the levels of anti NDV and anti IBDV antibodies in chickens were significantly higher than those of the rClone30 vaccine and commercial vaccines. Meanwhile, the contents and transcription levels of inflammatory factors in chickens inoculated with rClone30-VP2L-CH3-CH4-GMCSF were significantly increased, and the proliferation response of B cells, CD4+ and CD8+ T cells was also stronger. However, the rClone30-VP2L-CH3-CH4-GMCSF vaccine had no significant advantage over the rClone30-VP2L-GMCSF vaccine in any of the above-mentioned features. In summary, rClone30-VP2L-CH3-CH4-GMCSF can stimulate the body to produce a stronger immune response, showing its potential to be considered as vaccine against IBD and ND, but the addition of CH3-CH4 did not improve the vaccine's immune effect as expected. The research lays the foundation for developing vaccines for other infectious viral diseases and avoids a unrealistic vaccine optimization method.

Real-World Effectiveness of rFIXFc Prophylaxis in Patients with Haemophilia B Switched from Standard Half-Life Therapy in Three European Countries

INTRODUCTION

The current study describes real-world clinical outcomes and factor usage among patients with haemophilia B switching from standard half-life factor IX (SHL FIX) treatment to recombinant factor IX Fc fusion protein (rFIXFc) prophylaxis in European treatment centres.

METHODS

This non-interventional, retrospective, multicentre chart review evaluated medical records from adult and paediatric patients with haemophilia B in Denmark, Germany and the UK. Patients had documented SHL FIX treatment, on-demand or prophylaxis, for ≥ 6 months before starting rFIXFc prophylaxis, and subsequent data for ≥ 6 months afterwards (up to 24 months). Primary endpoints included annualised bleeding rates (ABRs), prophylactic factor consumption and injection frequency.

RESULTS

Data from 30 patients (24/30 [80.0%] with severe disease) showed overall mean (standard deviation, SD) ABRs of 4.7 (6.3) on SHL FIX treatment and 1.7 (2.3) after switching to rFIXFc prophylaxis. The reduction in mean (SD) ABRs was greater when switching from SHL FIX on-demand treatment (n = 6), with a decrease from 10.5 (9.9) to 2.6 (4.5), than when switching from SHL FIX prophylaxis (n = 24), with a decrease from 3.3 (4.3) to 1.5 (1.4). Among prior SHL FIX prophylaxis patients, switching to rFIXFc prophylaxis increased the proportion of those with zero bleeds from 21.7% to 45.8% during the 6 months before and after switching, respectively. In the total population, five of six target joints (83.3%) present when patients started rFIXFc prophylaxis subsequently resolved. In patients switching from SHL FIX prophylaxis to rFIXFc prophylaxis, mean (SD) weekly injection frequency was reduced by 1.0 (0.7) and mean (SD) factor consumption was reduced by 27.7 (49.6) IU/kg/week.

CONCLUSION

This study demonstrates the effectiveness of rFIXFc prophylaxis in real-world clinical practice. Improvements in both clinical effectiveness and factor usage associated with rFIXFc prophylaxis may potentially reduce patient burden and improve quality of life.

Recombinant factor IX Fc for major surgery in hemophilia B: factor IX plasma activity levels and effective hemostasis

Background

Major surgical procedures are associated with significant bleeding risk and infectious complications in patients with hemophilia, which may be minimized by factor replacement. Monitoring perioperative factor levels guides dosing to maintain adequate levels for hemostatic control.

Objectives

We report prospectively collected post hoc surgical data in patients with hemophilia B who underwent major surgery with extended half-life recombinant factor IX Fc fusion protein (rFIXFc) in phase 3 studies (B-LONG/Kids B-LONG and B-YOND).

Methods

Achieved FIX plasma levels were described for those who underwent major surgeries with ≥1 peak and/or predose FIX assessment available on the day of surgery (Day 0 [D0]) from the central laboratory. Dosing, injection frequency, adverse events, and hemostatic responses were assessed. Two representative cases were described further including blood loss, transfusions, and concomitant medication assessment.

Results

Of 35 major surgeries, 17 (N = 16 subjects) with sufficient FIX measurements were included in this analysis; 13 of 17 surgeries were orthopedic. On D0, a median loading (preoperative) dose of 101.1 International Units (IU)/kg/injection achieved a median peak FIX of 103.3 IU/dL. Across postoperative Days 1 to 3, 4 to 6, and 7 to 14, the median predose levels were 75.1 IU/dL with 1 injection/d, 71.6 IU/dL with 0 to 1 injection/d, and 43.2 IU/dL with 0 to 1 injection/d, respectively. Hemostasis was rated excellent (14 of 16) or good (2 of 16) across surgeries. Both case studies (knee arthroscopy and ankle fusion) illustrate measured FIX levels with rFIXFc.

Conclusion

The aggregate analysis and representative cases of major surgeries demonstrate that rFIXFc can achieve FIX levels for effective hemostasis during invasive high-risk procedures.