Clinical evaluation of an advanced category antihaemophilic factor prepared using a plasma/albumin-free method: pharmacokinetics, efficacy, and safety in previously treated patients with haemophilia A1

Efanesoctocog Alfa versus Standard and Extended Half-Life Factor VIII Prophylaxis in Adolescent and Adult Patients with Haemophilia A without Inhibitors

INTRODUCTION

In the Phase 3 XTEND-1 trial, (NCT04161495) efanesoctocog alfa prophylaxis provided superior bleed protection versus pre-study factor VIII (FVIII) replacement therapy in patients with severe haemophilia A. The aim of this study was to indirectly compare bleed outcomes between efanesoctocog alfa and standard/extended half-life (SHL and EHL) FVIII replacement therapies in adolescent and adult patients with severe haemophilia A without inhibitors.

METHODS

A systematic literature review was conducted to identify Phase 3 trials of EHL and SHL FVIII replacement therapies for comparison with efanesoctocog alfa data from XTEND-1. Matching-adjusted indirect comparisons were used to compare annualised bleeding rates (ABRs) for any, treated, joint, and spontaneous bleeds between efanesoctocog alfa and comparators. The estimates from respective comparisons were pooled using random-effect meta-analyses to evaluate the overall difference between efanesoctocog alfa and comparator therapies.

RESULTS

Four EHL therapies (rurioctocog alfa pegol, efmoroctocog alfa, turoctocog alfa pegol, damoctocog alfa pegol) and two octocog alfa SHL therapies were included. In meta-analyses, efanesoctocog alfa was associated with significantly lower ABRs for any [mean difference (95% CI) - 2.24 ( - 3.24; - 1.25)], spontaneous [ - 1.52 ( - 2.33; - 0.72)], and joint bleeds [ - 1.60 ( - 2.32; - 0.88)] versus EHL therapies, and with significantly lower ABRs for any [ - 3.61 ( - 4.43; - 2.79)], treated [ - 1.55 ( - 1.89; - 1.20)], spontaneous [ - 2.52 ( - 3.31; - 1.72)], and joint bleeds [ - 3.42 ( - 4.77; - 2.08)] versus SHL therapies.

CONCLUSION

Efanesoctocog alfa was associated with significantly lower ABRs (any, spontaneous and joint) compared with EHL or SHL prophylaxis therapies. Patients had, on average, 2.2 and 3.6 fewer bleeds per year versus EHL and SHL therapies, respectively.

The effectiveness and safety of octocog alfa in patients with hemophilia A: up to 7-year follow-up of the real-world AHEAD international study

Background

Real-world data assessing treatment outcomes in patients with hemophilia A in routine clinical practice are limited.

Objective

To evaluate the effectiveness and safety of octocog alfa in patients with moderate/severe hemophilia A receiving treatment in clinical practice.

Design

The international Antihemophilic Factor Hemophilia A Outcome Database study is an observational, noninterventional, prospective, multicenter study.

Methods

This planned interim data read-out was conducted following 7 years of observation of patients receiving octocog alfa (cut-off, 30 June 2020). The primary endpoint was joint health status, assessed by the Gilbert Score. Secondary endpoints included annualized bleeding rates (ABRs), Hemophilia Joint Health Score (HJHS), health-related quality of life, consumption, and safety. This post hoc analysis stratified data by hemophilia severity at baseline [moderate, factor VIII (FVIII) 1-5%; severe, FVIII <1%].

Results

Of the 711 patients in this analysis, 582 (82%) were receiving prophylaxis with octocog alfa at enrollment, and 498 (70%) had severe disease. Median Gilbert Scores were higher with on-demand therapy versus prophylaxis and scores were comparable in moderate and severe disease. In patients receiving prophylaxis, there was an improvement in HJHS Global Gait Score over 7 years of follow-up overall and in patients with severe disease. ABRs and annualized joint bleeding rates were low across all 7 years. An ABR of zero was reported in 34-56% of prophylaxis patients versus 20-40% in the on-demand group. ABRs were similar in severe and moderate disease. In total, 13/702 (1.9%) patients experienced 18 treatment-related adverse events.

Conclusion

These data demonstrate the long-term effectiveness and safety of octocog alfa in patients with moderate and severe hemophilia A, especially in those receiving prophylaxis. The high number of patients receiving on-demand treatment experiencing zero bleeds could be due to selection bias within the study, with patients with less severe disease more likely to be receiving on-demand treatment.

Trial registration

ClinicalTrials.gov: NCT02078427.

Immunogenicity of Therapeutic Biological Modalities - Lessons from Hemophilia A Therapies

The introduction and development of biologics such as therapeutic proteins, gene-, and cell-based therapy have revolutionized the scope of treatment for many diseases. However, a significant portion of the patients develop unwanted immune reactions against these novel biological modalities, referred to as immunogenicity, and no longer benefit from the treatments. In the current review, using Hemophilia A (HA) therapy as an example, we will discuss the immunogenicity issue of multiple biological modalities. Currently, the number of therapeutic modalities that are approved or recently explored to treat HA, a hereditary bleeding disorder, is increasing rapidly. These include, but are not limited to, recombinant factor VIII proteins, PEGylated FVIII, FVIII Fc fusion protein, bispecific monoclonal antibodies, gene replacement therapy, gene editing therapy, and cell-based therapy. They offer the patients a broader range of more advanced and effective treatment options, yet immunogenicity remains the most critical complication in the management of this disorder. Recent advances in strategies to manage and mitigate immunogenicity will also be reviewed.

Efficacy and safety of the B-domain-deleted TQG202 for on-demand treatment in moderate and severe haemophilia A patients: A multicentre, single-arm trial

INTRODUCTION

On-demand treatment is the most common treatment strategy for haemophilia A in China.

AIM

This study aims to evaluate the efficacy and safety of a human-derived B-domain-deleted recombinant factor VIII (TQG202) in the on-demand treatment of bleeding episodes in moderate/severe haemophilia A patients.

METHODS

This multicentre, single-arm clinical trial enrolled moderate/severe haemophilia patients previously treated with FVIII concentrates for ≥50 exposure days (EDs) from May 2017 to October 2019. TQG202 was injected intravenously on-demand for bleeding episode management. The primary endpoints were the infusion efficiency at 15 and 60 min after the first administration and haemostatic efficacy of the first bleeding episode. Safety was also monitored.

RESULTS

Fifty-six participants were enrolled with a median age of 24.5 (range: 12-64) years old. The median total dose of TQG202 was 29,250 IU per participant (range: 1750-2,02,500), and the median number of administrations was 24.5 (2-116). The median infusion efficiency at 15 and 60 min after the first administration was 155.4% and 145.2%, respectively. Among the 48 first bleeding episodes evaluated, 47 (83.9%, 95% CI: 71.7%-92.4%) had a haemostatic efficacy rating of excellent or good. Eleven (19.6%) participants had treatment-related adverse events (TRAEs), but no ≥grade 3 TRAE was observed. Inhibitor development (0.6BU) was observed in one participant (1.8%) after 22 EDs, but was undetectable after 43 EDs.

CONCLUSION

TQG202 for on-demand treatment in moderate/severe haemophilia A shows effective control of the bleeding symptoms, with a low incidence of adverse events and inhibitors development.

Immunogenicity of Current and New Therapies for Hemophilia A

Anti-drug antibody (ADA) development is a significant complication in the treatment of several conditions. For decades, the mainstay of hemophilia A treatment was the replacement of deficient coagulation factor VIII (FVIII) to restore hemostasis, control, and prevent bleeding events. Recently, new products have emerged for hemophilia A replacement therapy, including bioengineered FVIII molecules with enhanced pharmacokinetic profiles: the extended half-life (EHL) recombinant FVIII products. However, the main complication resulting from replacement treatment in hemophilia A is the development of anti-FVIII neutralizing alloantibodies, known as inhibitors, affecting approximately 25–30% of severe hemophilia A patients. Therefore, the immunogenicity of each FVIII product and the mechanisms that could help increase the tolerance to these products have become important research topics in hemophilia A. Furthermore, patients with inhibitors continue to require effective treatment for breakthrough bleedings and procedures, despite the availability of non-replacement therapy, such as emicizumab. Herein, we discuss the currently licensed treatments available for hemophilia A and the immunogenicity of new therapies, such as EHL-rFVIII products, compared to other products available.

Quality of clinical studies present in the package inserts of coagulation factors used in the treatment of hemophilia

OBJECTIVE

To identify and analyze the quality of scientific evidence from clinical efficacy studies present in the package inserts of coagulation factors, used in the treatment of hemophilia A and B.

METHODS

Documentary study developed in two stages. The first stage consisted of identifying the medicine packages inserts electronically registered in the Brazilian Health Regulatory Agency, and analyzing the availability of the bibliographic references cited therein. This analysis was conducted in the PubMed, SciELO, Google Scholar, and Web of Science databases. The second step was the analysis of the methodological quality of the efficacy studies. Two trained researchers used the Cochrane Collaboration Risk of Bias version 5.1.0 tools for methodological quality analysis, and Review Manager 5.4 software to generate the risk of bias graph.

RESULTS

Of the 17 medicines listed, 7 had referenced package inserts. Of these, 10 studies were eligible for analysis of methodological quality. More than half of the analyzed studies did not control for selection, performance, and detection bias. A total of 100% controlled attrition and reporting biases, and 50% had a high risk of conflict of interest.

CONCLUSION

The biases present are significant and may have influenced the overestimation of the effects of the outcomes of each of the studies.

Application of Multicriteria Decision Analysis to Determine the Value of Prophylaxis Relative to On-Demand Treatment in Hemophilia A and Emicizumab versus Replacement Therapy in the Greek Healthcare Setting

BACKGROUND AND OBJECTIVE

Hemophilia A (HA) is a rare disease that is characterized by congenital underproduction or dysfunction of the endogenous coagulation factor VIII (FVIII). The aim of the present study was to determine the value of prophylaxis versus on-demand treatment strategies for moderate to severe HA (MtSHA) patients and the value of emicizumab in the prophylaxis of MtSHA in Greece, compared with short half-life (SHL) FVIII and extended half-life (EHL) FVIII through multicriteria decision analysis (MCDA).

METHODS

A literature review was performed to identify a set of criteria relevant to the therapeutic approaches and therapies under investigation. A performance matrix was populated by two literature reviews and meta-analyses. The criteria selected were hierarchically classified by allocating weights on a 0-100 scale. The performances of therapies were scored at the 100-point scale. The value judgments utilized for weighing and scoring were sourced via a survey among independent multidisciplinary system stakeholders. A linear additive value function was used for the calculation of total value estimates.

RESULTS

The participants ranked 'annual number of bleedings per patient' and 'percentage of target joint bleeds' as the most important criteria, while the least important criterion was the 'annual treatment cost' for both assessments. Based on the weights elicited and the performance in each criterion, the overall value score was higher for prophylaxis treatment (58.27) compared with on-demand treatment (40.13). In the other comparison, the most valued treatment was emicizumab (77.05) followed by EHL FVIII (71.52) and SHL FVIII (19.88). According to the participants, the most important factors for managing MtSHA patients are those related to successful management of bleeding events given their contribution to improved quality of life (QoL) and reduced morbidity.

CONCLUSIONS

This MCDA has shown that the prophylaxis strategy was perceived as a more valuable option for managing MtSHA patients when compared with the on-demand strategy. Moreover, emicizumab adds higher value and improves patient QoL compared with replacement therapy for MtSHA in Greece. Emicizumab addresses important unmet needs due to its improved efficacy and mode of administration.

Matching-Adjusted Indirect Comparison of Efficacy and Consumption of rVIII-SingleChain Versus Two Recombinant FVIII Products Used for Prophylactic Treatment of Adults/Adolescents with Severe Haemophilia A

Introduction

Given the relatively small number of patients with haemophilia A, head-to-head comparisons between recombinant FVIII (rFVIII) products are difficult to conduct. This study compared the efficacy and consumption of rVIII-SingleChain (lonoctocog alfa, AFSTYLA^®) with rAHF-PFM (octocog alfa, Advate^®) and rFVIIIFc (efmoroctocog alfa, Elocta^®), for the prophylaxis and treatment of bleeding episodes in previously treated adolescents/adults with severe haemophilia A, through a matching-adjusted indirect comparison (MAIC).

Methods

A systematic literature review identified published clinical trials for rAHF-PFM and rFVIIIFc. Individual patient data for rVIII-SingleChain were used to match baseline patient characteristics to those from published trials, using an approach similar to propensity score weighting. After matching, annualized bleeding rates (ABR), percentage of patients with zero bleeds, and rFVIII consumption were compared across trial populations.

Results

Published data were identified from two rAHF-PFM trials and one rFVIIIFc trial. rVIII-SingleChain had similar ABR (risk ratio [RR]: 0.74 [0.16; 3.48]; RR: 1.18 [0.85; 1.65]) and percentage of patients with zero bleeds (odds ratio [OR]: 1.34 [0.56; 3.22]; OR: 0.78 [0.47; 1.31]) versus rAHF-PFM and rFVIIIFc, respectively. Annual rVIII-SingleChain consumption was significantly lower than rAHF-PFM (mean difference: − 1507.66 IU/kg/year [− 2011.71; − 1003.61]) and equivalent to rFVIIIFc (RR: 0.96 [0.62; 1.49]).

Conclusion

Although limited to published information for comparator trials, these results suggest that with an annualized rFVIII consumption comparable to rFVIIIFc, but significantly lower than rAHF-PFM, routine prophylaxis with rVIII-SingleChain is able to maintain a similar ABR and percentage of patients with zero bleeds, attesting to the long-acting nature of rVIII-SingleChain.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-021-01853-0.

It is difficult to directly compare different recombinant FVIII products in head-to-head studies because there are few patients with haemophilia A. This study aimed to indirectly compare the efficacy and consumption of different recombinant FVIII products in the prophylactic treatment of haemophilia A using published clinical data. A proven method for performing indirect comparisons of products is referred to as a matching-adjusted indirect comparison. Using this approach, we were able to compare rVIII-SingleChain with two other recombinant FVIII products (rAHF-PFM and rFVIIIFc). Our results suggest that annual FVIII consumption with rVIII-SingleChain is comparable to rFVIIIFc, but is significantly lower than rAHF-PFM, while maintaining a similar bleeding rate. These results highlight the long-acting nature of the product.

Clinical benefits of a Bayesian model for plasma-derived factor VIII/VWF after one year of pharmacokinetic-guided prophylaxis in severe/moderate hemophilia A patients

INTRODUCTION

Individual pharmacokinetic (PK) profiling in hemophilia A (HA) helps to individualize prophylaxis using population PK models (popPK). A specific popPK model for plasma-derived factor VIII containing von-Willebrand Factor (pdFVIII/VWF) was developed.

AIM

To compare standard versus PK-driven prophylaxis, using a generic or a specific popPK model for pdFVIII/VWF.

MATERIALS AND METHODS

A prospective study conducted in HA patients in prophylaxis with pdFVIII/VWF (Fanhdi®) comparing three one-year study periods: (1) standard prophylaxis, (2) PK-guided prophylaxis using a generic pdFVIII popPK model which described FVIII activity irrespective of FVIII concentrate, and (3) PK-guided prophylaxis with specific pdFVIII/VWF popPK model. PK parameters analyzed were half-life, trough levels (TL) at 24, 48 and 72 h, and time to reach FVIII levels of 1, 2, 5% (T5%). Clinical outcomes were dose/kg, FVIII consumption, annualized bleeding rate (ABR), annualized joint bleeding rate (AJBR), spontaneous and traumatic bleeds.

RESULTS

Of the 30 analyzed patients, 28 had severe HA and the median age was 31.2. Fifteen patient's prophylaxis doses were PK-adjusted. After the generic PK-guided prophylaxis period, younger patients showed more joint bleeds, a shorter half-life, and lower TL48, TL72 and T5%. Using the specific pdFVIII/VWF popPK model compared with standard prophylaxis, a lower spontaneous AJBR was observed in the entire cohort and in patients aged >15 years. Additionally, lower spontaneous ABR was reported in patients aged ≤15 years comparing specific and generic models.

CONCLUSIONS

PK-guided prophylaxis with a specific pdFVIII/VWF popPK model allowed treatment individualization and improved bleeding control in routine clinical practice, especially in younger patients with short pdFVIII/VWF half-lives.

MRI predicts 5-year joint bleeding and development of arthropathy on radiographs in hemophilia

Magnetic resonance imaging (MRI) is considered as the reference standard to assess early joint changes in hemophilia. However, the clinical relevance of MRI findings is still unknown. The aim of this prospective study was to assess the predictive value of MRI for 5-year joint bleeding and progression of arthropathy in patients with hemophilia. Both knees and ankles of patients with hemophilia and absent or limited arthropathy on radiographs were assessed by using MRI and radiographs. MRI scans were scored according to the International Prophylaxis Study Group MRI score for hemophilic arthropathy. Patients were followed up for 5 years, including assessment of joint bleeding and repeated radiographic assessment. Associations between baseline MRI findings with 5-year bleeding and progression of arthropathy were expressed as odds ratios (OR), adjusted for severity of disease and joint bleeding history. Baseline assessment included 104 joints of 26 patients with hemophilia (median age, 21 years). Four ankles with severe joint changes were excluded. Follow-up was available for 96 (92%) of 104 joints. During 5 years of follow-up, bleeding was reported for 36% of joints. Five-year bleeding was significantly increased in joints with synovial hypertrophy at 80% vs 27% in joints without synovial hypertrophy (OR, 10.1; 95% confidence interval, 3.4-31.3). In joints with normal baseline radiographs, any osteochondral or synovial changes on MRI were associated with radiographic changes 5 years later (positive predictive value, 75%; negative predictive value, 98%). Joints with synovial hypertrophy on MRI had a significantly higher chance of 5-year bleeding. All MRI changes, except effusion, were strong predictors for development of arthropathy on radiographs.

FVIII half-life extension by coadministration of a D'D3 albumin fusion protein in mice, rabbits, rats, and monkeys

A novel mechanism for extending the circulatory half-life of coagulation factor VIII (FVIII) has been established and evaluated preclinically. The FVIII binding domain of von Willebrand factor (D'D3) fused to human albumin (rD'D3-FP) dose dependently improved pharmacokinetics parameters of coadministered FVIII in all animal species tested, from mouse to cynomolgus monkey, after IV injection. At higher doses, the half-life of recombinant FVIII (rVIII-SingleChain) was calculated to be increased 2.6-fold to fivefold compared with rVIII-SingleChain administered alone in rats, rabbits, and cynomolgus monkeys, and it was increased 3.1-fold to 9.1-fold in mice. Sustained pharmacodynamics effects were observed (ie, activated partial thromboplastin time and thrombin generation measured ex vivo). No increased risk of thrombosis was observed with coadministration of rVIII-SingleChain and rD'D3-FP compared with rVIII-SingleChain alone. At concentrations beyond the anticipated therapeutic range, rD'D3-FP reduced the hemostatic efficacy of coadministered rVIII-SingleChain. This finding might be due to scavenging of activated FVIII by the excessive amount of rD'D3-FP which, in turn, might result in a reduced probability of the formation of the tenase complex. This observation underlines the importance of a fine-tuned balance between FVIII and its binding partner, von Willebrand factor, for hemostasis in general.

Comparative analysis of the pivotal studies of extended half-life recombinant FVIII products for treatment of haemophilia A

The need to reduce the burden of injections, and improve adherence and clinical outcomes in haemophilia A led to the development of recombinant FVIII products endowed with an extended plasma half-life (EHL-rFVIII) in comparison with standard half-life products (SHL-rFVIII). Lack of head-to-head studies makes difficult to grasp the relative value of each treatment option. We conducted a combined evaluation of the individual pivotal trials in order to assess between-product differences regarding the reported efficacy results and FVIII consumption. We evaluated 4 EHL-rFVIII products available to treat patients with haemophilia A without inhibitors and also a SHL-rFVIII as a comparator. In the frame of these clinical studies, all the EHL-rFVIII products showed a decrease in the injection burden coupled with good clinical efficacy, even though there were between-product differences in terms of reduction in injection frequencies. Further, between-product differences in terms of weekly/yearly consumption of rFVIII expressed in IU/Kg were identified, suggesting a different economic impact for the different EHL-rFVIII products in the context of comparable clinical efficacy. The present findings based upon the review of pivotal studies done in the frame of a highly selected clinical scenario should be integrated with real-life data.

Phase 4 Safety and Efficacy Study of Antihemophilic Factor (Recombinant) in Previously Treated Chinese Patients With Severe/Moderately Severe Hemophilia A

Antihemophilic factor (recombinant) (rAHF; ADVATE^®; Baxalta US Inc., a Takeda company, Lexington, MA, USA) is indicated for the treatment and prevention of bleeding in patients with hemophilia A. We aimed to assess the safety and efficacy of standard prophylaxis versus on-demand treatment with rAHF in previously treated Chinese patients with severe/moderately severe hemophilia A. This open-label, sequential, interventional, postapproval study (NCT02170402) conducted in China included patients of any age with hemophilia A with factor VIII (FVIII) level ≤2%. Patients received 6 months’ on-demand rAHF then 6 months’ rAHF prophylaxis (20-40 IU/kg every 48 ± 6 hours). The primary objective was percentage reduction in annualized bleeding rate (ABR) in the per-protocol analysis set (PPAS); secondary objectives included ABR by bleeding subtype, hemostatic efficacy, immunogenicity, and safety. Of 72 patients who received ≥1 rAHF dose, 61 were included in the PPAS. Total ABR was lower during prophylaxis (mean 2.5, 95% CI 1.5-3.7; median 0) versus on-demand treatment (mean 58.3, 95% CI 52.5-64.7; median 53.9), representing a 95.9% risk reduction. Similar findings in favor of prophylaxis were observed for all types of bleeding event by cause and location. rAHF hemostatic efficacy was rated as “excellent”/“good” in 96.1% of treated bleeding events. Transient FVIII inhibitors (0.6-1.7 BU) in 4 patients resolved before study end; no unexpected safety issues were observed. rAHF prophylaxis in this study of previously treated Chinese patients with severe/moderately severe hemophilia A resulted in a clear reduction in bleeding events versus rAHF on-demand treatment, with no change in safety profile.

A Practical, One-Clinic Visit Protocol for Pharmacokinetic Profile Generation with the ADVATE myPKFiT Dosing Tool in Severe Hemophilia A Subjects

Standard pharmacokinetic (PK) assessments are demanding for persons with hemophilia A, requiring a 72-hour washout and 5 to 11 timed blood samples. A no-washout, single-clinic visit, sparse sampling population PK (PPK) protocol is an attractive alternative. Here, we compared PK parameters obtained with a traditional washout, 6-sampling time point PPK protocol with a no-washout, single-clinic visit, reverse 2-sampling time point PPK protocol in persons with severe hemophilia A (SHA) receiving ADVATE. A total of 39 inhibitor-negative males with SHA (factor VIII activity [FVIII:C] < 2%) were enrolled in a prospective sequential design PK study. Participants completed a washout, 6-sampling time point PPK protocol as well as a no-washout, reverse 2-sampling time point protocol, with samples taken during a single 3-hour clinic visit 24 hours post home infusion of FVIII and then 3 hours post infusion in clinic. FVIII:C levels were analyzed by one-stage and chromogenic assays; blood group and von Willebrand factor antigen (VWF:Ag) were determined; and PK parameters were analyzed using the ADVATE myPKFiT dosing tool. There was moderate to almost perfect agreement for the PK parameters obtained with the 2- and the 6- point PPK protocols using a one-stage FVIII:C assay and a substantial to almost perfect agreement using a chromogenic FVIII:C assay. Significant associations between specific PK parameters and blood group and VWF:Ag were observed. The no-washout, single-clinic visit, reverse 2-sampling time point PPK protocol can be used in the routine clinical setting since it demonstrates sufficient accuracy compared with the more demanding and less practical washout, 6-sampling time point PPK protocol in persons with SHA receiving ADVATE.

Long-term safety and efficacy of N8-GP in previously treated adults and adolescents with hemophilia A: Final results from pathfinder2

BACKGROUND

N8-GP (turoctocog alfa pegol; Esperoct® , Novo Nordisk A/S, Bagsvaerd, Denmark) is a glycoPEGylated human recombinant factor VIII with a half-life of ~1.6-fold of standard FVIII products. pathfinder2 (NCT01480180) was a multi-national, open-label trial of N8-GP in previously treated adolescent and adult patients with severe hemophilia A.

OBJECTIVE

We report end-of-trial efficacy and safety of N8-GP from pathfinder2.

METHODS

pathfinder2 main phase and extension phase part 1 results have been previously reported. During extension phase part 2, patients could switch from N8-GP prophylaxis 50 IU/kg every fourth day (Q4D) or 75 IU/kg once weekly (Q7D), depending on bleeding status. Extension phase part 2 collected long-term safety and efficacy data for all regimens until trial end (first patient in main phase, 30 January 2012; trial end, 10 December 2018).

RESULTS

Overall, 186 patients were exposed to N8-GP for up to 6.6 years (median 5.4 years). The estimated annualized bleeding rate (ABR) was 2.14 (median 0.84) for the Q4D prophylaxis arm and 1.31 (median 1.67) for the Q7D prophylaxis arm. Nearly 30% of patients experienced zero bleeds throughout the entire duration of the trial, the hemostatic response was 83.2% across all treatment arms, and patient-reported outcomes were maintained or slightly improved. No safety concerns were detected.

CONCLUSION

Data from the completed pathfinder2 trial, one of the largest and longest-running clinical trials to investigate treatment of severe hemophilia A, demonstrate the efficacy and safety of N8-GP in previously treated adolescent and adult patients.

Long-term safety and efficacy results from the phase 3b, open-label, multicentre Continuation study of rurioctocog alfa pegol for prophylaxis in previously treated patients with severe haemophilia A

INTRODUCTION

Previous studies reported the efficacy and safety profile of extended half-life PEGylated recombinant factor VIII (FVIII) rurioctocog alfa pegol (TAK-660, SHP660, BAX 855) in preventing bleeding in haemophilia A patients.

AIM

This study evaluated long-term safety and efficacy of rurioctocog alfa pegol for prophylaxis and treatment of bleeding in previously treated children and adults.

METHODS

In this phase 3b, prospective, open-label, multicentre study (NCT01945593), eligible patients ≤ 75 years with severe haemophilia A (FVIII < 1%) received prophylactic rurioctocog alfa pegol in a fixed dose (FD, twice-weekly or less frequent) or pharmacokinetic (PK)-tailored dose regimen. Co-primary endpoints were incidence of confirmed FVIII inhibitory antibody development and spontaneous annualized bleed rate (ABR), analysed using a generalised linear model. Secondary endpoints included overall haemostatic efficacy, occurrence of adverse events and health-related quality of life (HRQoL).

RESULTS

Overall, 216 patients were included; mean (SD) age at enrolment was 22.8 (15.7) years. No patients developed confirmed FVIII inhibitors. The point estimate (95% CI) of mean spontaneous ABR was 1.20 (0.92-1.56) among 186 patients receiving twice-weekly FD prophylaxis and 0.96 (0.54-1.71) among 25 patients receiving PK-tailored prophylaxis. Overall haemostatic efficacy was rated good or excellent in 88.6% of all bleeds. No new safety signals were observed. Patients reported improvements in HRQoL measures of pain, and physical and mental well-being.

CONCLUSION

These results highlight the long-term safety and efficacy of rurioctocog alfa pegol prophylaxis in previously treated children and adults with severe haemophilia A, with a safety profile similar to previous studies and continuing ABR reduction.

Postauthorization safety surveillance study of antihaemophilic factor (recombinant) reconstituted in 2 mL sterile water for injection in children with haemophilia A

Introduction

Antihaemophilic factor (recombinant) (rAHF; ADVATE^®) is approved for prophylaxis and treatment of bleeding in children and adults with haemophilia A. Reconstitution in 2 mL sterile water for injection instead of 5 mL allows for a 60% reduction in infusion volume and administration time, but could increase the likelihood of hypersensitivity and infusion‐related reactions, especially in children.

Aim

To assess local tolerability, safety and effectiveness of rAHF 2 mL during routine clinical practice factor VIII (FVIII) replacement (on‐demand and prophylaxis) in children with severe (FVIII < 1%) or moderately severe (FVIII 1%‐2%) haemophilia A.

Methods

This was a prospective, non‐interventional, postauthorization safety surveillance study (NCT02093741). Eligible patients were previously treated with rAHF and had a negative inhibitor test result during ≤10 exposure days prior to study entry.

Results

Of 65 patients enrolled (0‐11 years of age), 54 and 11 had severe and moderately severe haemophilia A, respectively; 56 patients received prophylaxis, and 11 had ≤50 exposure days, of which 4 had ≤4 exposure days. No patients reported local hypersensitivity reactions, treatment‐related adverse events or developed inhibitors. Investigators rated overall effectiveness of rAHF 2 mL prophylaxis as excellent or good. Ninety‐four bleeding events in 34 patients were treated. Haemostatic effectiveness was rated as excellent or good for 75.8% of bleeds; 86.2% of bleeds required 1 or 2 infusions.

Conclusion

In children with severe/moderately severe haemophilia A, no hypersensitivity reactions were reported with rAHF 2 mL treatment, and the safety and effectiveness are consistent with data previously reported for rAHF 5 mL.

Turoctocog alfa pegol provides effective management for major and minor surgical procedures in patients across all age groups with severe haemophilia A: Full data set from the pathfinder 3 and 5 phase III trials

INTRODUCTION

Turoctocog alfa pegol is a glycoPEGylated recombinant factor VIII (FVIII) with an extended half-life developed for prophylaxis, treatment of bleeds and perioperative management in patients with haemophilia A.

AIM

Evaluate the efficacy and safety of turoctocog alfa pegol treatment for major and minor surgeries in the pathfinder 3 and 5 phase III trials.

METHODS

Adults/adolescents aged ≥12 years with severe haemophilia A (FVIII <1%) received perioperative turoctocog alfa pegol treatment planned to achieve FVIII activity levels >80% during major surgery (pathfinder 3). The primary end point was haemostatic efficacy during surgery; secondary end points were blood loss, haemostatic effect postsurgery, consumption, transfusions, safety and health economics. Children (0-11 years) undergoing minor surgeries received 20-75 IU/kg turoctocog alfa pegol at Investigator's discretion (pathfinder 5).

RESULTS

pathfinder 3 included 35 patients undergoing 49 major surgeries. Haemostasis was successful in 47/49 (95.9%) surgeries; two had moderate haemostatic responses. Median (mean) blood loss during major surgery was 75 (322.6) mL. Four bleeds were reported postsurgery; three were successfully treated with turoctocog alfa pegol (one was not evaluated). On the day of surgery, overall mean (median) dose was 75.5 (74.5) IU/kg and mean (median) number of doses was 1.7 (2.0). Five procedures required 11 transfusions on the day of surgery or days 1-6. No safety concerns or inhibitors were identified. Forty-five minor surgeries in 23 children were performed without complications.

CONCLUSION

Turoctocog alfa pegol was effective for perioperative haemostatic management of major and minor surgeries in patients across age groups with severe haemophilia A.

Status of Recombinant Factor VIII Concentrate Treatment for Hemophilia a in Italy: Characteristics and Clinical Benefits

The current interest in recombinant factor VIII (rFVIII) products stems from the fact that they offer a technological solution to prolonging the half-life of and reducing the risk of formation of alloantibodies (inhibitors) against FVIII in treated patients with hemophilia A (HA). The Italian health care system has authorized the use of a wide range of rFVIII concentrates of the first, second, and third generation, as well as new innovative rFVIII preparates with an extended half-life (EHL) (Kogenate FS®-Bayer, belonging to the second generation and replaced since 2017 by a product consisting of the same modified molecule; because it is only available until the end of the current year, it will not be considered in this review). Some of these products have unique pharmacodynamic and pharmacokinetic (PK) profiles, including an EHL. The first-generation full-length rFVIII (FL-rFVIII), octocog alfa (Recombinate® Baxter/BIOVIIIx), although the oldest rFVIII product, has several desirable features. Third-generation products include two modified octocog alfa molecules (Advate®, Shire; Kovaltry®, Bayer) as well as the B domain-deleted rFVIII (BDD-rFVIII) moroctocog alfa (ReFacto®-Pfizer). The B domain-truncated (BDT-rFVIII) turoctocog alfa (NovoEight®, Novo Nordisk), the BDD-rFVIII simoctocog alfa (Nuwiq®, Kedrion), the single-chain BDT-rVIII lonoctocog alfa (Afstyla®, CSL Behring), and the BDD-rFVIIIFc efmoroctocog alfa (Elocta®, Sobi-Biogen) are new, innovative products. Simoctocog alfa, because its peculiarities, is considered a fourth-generation rFVIII concentrate. Turoctocog alfa, simoctocog alfa, and lonoctocog alfa have a high affinity for von Willebrand factor (vWF) that reduces renal clearance and prolongs the half-life of rFVIII. Efmoroctocog alfa, a first-in-class rFVIII-Fc fusion protein (rFVIIIFc), has a half-life 1.5–1.8 times longer than that of conventional plasma-derived FVIII (pd-rFVIII) and other rFVIII products. Clinical studies have evaluated the efficacy, safety, and inhibitor development of all these innovative concentrates in both previously treated (PTPs) and untreated patients (PUPs). This review considers the rFVIII products that are indicated for the treatment of patients with severe HA, focusing on those that are commercially available in Italy. Their PK characteristics, immunogenicity, and clinical benefits are discussed and compared.

Efficacy and safety of simoctocog alfa (Nuwiq®) in patients with severe hemophilia A: a review of clinical trial data from the GENA program

Simoctocog alfa (human-cl rhFVIII, Nuwiq®) is a 4th generation recombinant FVIII (rFVIII), without chemical modification or fusion with any other protein/fragment. Nuwiq® is produced in a human embryonic kidney cell line (HEK293F), which ensures human-specific post-translational protein processing. Nuwiq® was evaluated in seven prospective clinical studies in 201 adult and pediatric previously treated patients (PTPs) with severe hemophilia A. The NuProtect study in 110 previously untreated patients (PUPs) is ongoing. The mean half-life of Nuwiq® was 15.1–17.1 h in PTP studies with adults and adolescents, and 12.5 h in children aged 2–12 years. Clinical trials in PTPs demonstrated the efficacy and safety of Nuwiq® in the prevention and treatment of bleeds and as surgical prophylaxis. In the NuPreviq study of pharmacokinetic (PK)-guided personalized prophylaxis in 66 adult PTPs, 83% of patients had no spontaneous bleeds during 6 months of personalized prophylaxis and 57% were treated ⩽2 per week. No FVIII inhibitors were detected in PTPs after treatment with 43,267 injections and >80 million IU of Nuwiq®. Interim data for 66 PUPs with ⩾20 exposure days to Nuwiq® in NuProtect demonstrated a low cumulative high-titer inhibitor rate of 12.8% [actual incidence 12.1% (8/66)] and convincing efficacy and safety.

Matching-adjusted indirect comparisons of annualized bleeding rate and utilization of BAY 94-9027 versus three recombinant factor VIII agents for prophylaxis in patients with severe hemophilia A

Background: BAY 94-9027 is an extended half-life recombinant factor VIII (rFVIII) that prevents bleeding in persons with hemophilia A at twice-weekly, 5-day, and 7-day dosing intervals. In rare diseases such as hemophilia, where small populations preclude head-to-head comparisons in randomized controlled trials, outcomes from different studies can be compared by matching-adjusted indirect treatment comparisons (MAICs) via matched summary statistics of individual patient data. This study compared MAIC-adjusted outcomes of BAY 94-9027 with other FVIII agents for prophylaxis of hemophilia. Methods: Weighted patient data from the BAY 94-9027 PROTECT VIII trial were used to compare annualized bleeding rates (ABRs), percentage of patients with zero bleeds, and factor utilization against published data on rFVIII-Fc fusion protein (rFVIIIFc), BAX 855, and recombinant antihemophilic factor/plasma/albumin-free method (rAHF-PFM). Results: After matching BAY 94-9027 and comparators, the mean BAY 94-9027 utilization was significantly lower than rFVIIIFc pre- and post-matching (66.2 vs 82.2 IU/kg/week; 66.5 vs 82.2 IU/kg/week; both P<0.001). Median BAY 94-9027 utilization (IU/kg/week) trended lower than BAX 855 (64.3 vs 87.4) and rAHF-PFM (2004 study: 64.0 vs 107.5; 2012 study: 63.6 vs 109.9). Mean ABRs and percentages of patients with zero bleeds were similar post-matching between BAY 94-9027 and comparators. Conclusion: BAY 94-9027 demonstrated similar MAIC-adjusted ABR with lower utilization than rFVIIIFc, BAX 855, and rAHF-PFM.

Inhibitor development, safety and efficacy of Advate® among previously treated patients with hemophilia A in a postmarketing surveillance in Japan

Rurioctocog alfa (recombinant factor VIII: Advate^®) is available for the control of bleeding in patients with hemophilia A in Japan. To evaluate the inhibitor development, safety, and efficacy of rurioctocog alfa, a non-interventional and observational postmarketing surveillance was conducted on 352 previously treated Japanese patients aged 1-76 years with ≥ 4 exposure days under the conditions of routine clinical practice. A post-hoc comparison of the mean annualized bleeding rates which required treatment with rurioctocog alfa detected a statistically significant difference (P < 0.0001) between patients treated on regular prophylaxis (8.5 bleeds/year) and patients treated on an on-demand basis (36.6 bleeds/year). Favorable prophylactic and on-demand hemostatic efficacy ("excellent" or "good") were shown in 88.5-100% of patients across all treatment regimens. A total of 22 events of adverse drug reactions were reported in 13 male patients. Of the 352 patients, 3 (0.9%) patients, all of whom had ≤ 50 exposure days before enrollment, developed de novo FVIII inhibitor. No deaths or allergic reactions were reported. Rurioctocog alfa was found to be well-tolerated and effective among patients with hemophilia A in a postmarketing routine clinical practice.

Budget impact analysis of the use of extended half-life recombinant factor VIII (efmoroctocog alfa) for the treatment of congenital haemophilia a: the Italian National Health System perspective

Background

Congenital haemophilia A (HA) is a rare, inherited, life-long bleeding disorder characterised by prolonged or spontaneous bleeding due to the lack of clotting factor VIII (FVIII) in the body. Treatment for HA involves FVIII replacement therapy and poses great economic burden to National Health Systems and to society. Availability of novel products as extended half-life clotting factor products might change treatment approches and their economic evaluation is essential for an informed treatment choice. Accordingly the objective of the present work is to analyse the economic impact of using efmoroctocog alfa (recombinant factor VIII-Fc fusion protein, rFVIIIFc) for the treatment of children and adults with severe congenital haemophilia A (HA).

Methods

A budget impact analysis was performed to estimate the economic impact of the introduction of rFVIIIFc in the market-mix of products for the treatment of HA. The analysis condidered a 3-year time horizon and the Italian National Health System (INHS) perspective. The model estimated drug costs associated with the treatment of HA in the current scenario - representing the marketplace forecast for the time period of interest assuming that rFVIIFc is not introduced - and a new scenario, assuming that rFVIIIFc is available in the market. The size of the target population was calculated using epidemiological national data. Univariate one-way sensitivity analyses and scenario analyses were performed.

Results

Overall 3-year costs of treating the HA population in the current scenario were 555,277,691 Euro for the INHS. With the introduction of rFVIIIFc, the costs were reduced to 541,897,466 Euro suggesting potential savings to the INHS of 13,380,255 Euro. Results were consistent at variation of most of the model’s parameters; only in case of lower dosage of conventional products and higher dosage of rFVIIIFc, costs for the INHS increased, in both cases, of about 20 million Euro.

Conclusions

The use of rFVIIIFc for the treatment of HA has been recently approved by the Italian Medicines Agency (AIFA) and this is the first study estimating the financial impact of this new therapeutic alternative in the Italian context. The analysis suggests that rFVIIIFc use does not result in higher expenditure for the INHS.

Improved Pharmacokinetics with BAY 81-8973 Versus Antihemophilic Factor (Recombinant) Plasma/Albumin-Free Method: A Randomized Pharmacokinetic Study in Patients with Severe Hemophilia A

Background

BAY 81-8973 is a full-length, unmodified, recombinant human factor VIII (FVIII) for the treatment of hemophilia A.

Objective

The aim of this study was to compare the pharmacokinetic (PK) profile of BAY 81-8973 with antihemophilic factor (recombinant) plasma/albumin-free method (rAHF-PFM)

Patients/Methods

In this phase I, open-label, crossover study, men aged 18–65 years with severe hemophilia A and ≥150 exposure days to FVIII were randomized to receive a single intravenous infusion of 50 IU/kg BAY 81-8973 or rAHF-PFM, followed by crossover to a single infusion of the other treatment. FVIII levels were measured in plasma over 48 h using one-stage and chromogenic assays. PK parameters, including area under the curve from time zero to the last data point (AUC_last; primary outcome) and half-life (t_½) were calculated. A population PK model was developed to simulate various treatment scenarios.

Results

Eighteen patients were randomized and analyzed. Using both assays, geometric mean (coefficient of variation [%CV]) AUC_last was significantly higher, and t_½ was significantly longer, for BAY 81-8973 versus rAHF-PFM (one-stage, AUC_last: 1660 IU·h/dL [29.4] vs. 1310 IU·h/dL [29.0], p < 0.0001; one-stage, t_½: 14.5 [25.7] vs. 11.7 h [27.3], p < 0.0001). Simulations showed that median time to 1 IU/dL was approximately 27% longer for BAY 81-8973 versus rAHF-PFM over doses of 25–50 IU/kg; plasma levels >1 IU/dL could be maintained with 14.4 IU/kg BAY 81-8973 or 39.1 IU/kg rAHF-PFM 3×/week.

Conclusions

BAY 81-8973 showed a superior PK profile versus rAHF-PFM. The same FVIII trough threshold level could be achieved with lower doses of BAY 81-8973 versus rAHF-PFM.

ClinicalTrials.gov: NCT02483208.

Advances and innovations in haemophilia treatment

Haemophilia is a rare disease for which the approved therapeutic options have remained virtually unchanged for 50 years. In the past decade, however, there has been an explosion of innovation in the treatment options that are either in development or have been approved for haemophilia, including engineered clotting factors and an extensive pipeline of new approaches and modalities. Several of these new modalities, especially gene therapy, demonstrate proof of principle in haemophilia but could have broader applications. These advances, in combination with better diagnostics, are now enabling clinicians to improve the standard of care for people with haemophilia. The different mechanisms of action and modifications used in these therapies have implications for their safe and efficacious use, which must be balanced with their therapeutic utility. This Review focuses on the biological aspects of the most advanced and innovative approaches for haemophilia treatment and considers their future use.

Cost-utility analysis of life-long prophylaxis with recombinant factor VIIIFc vs recombinant factor VIII for the management of severe hemophilia A in Sweden

AIMS

Prophylaxis with recombinant factor VIII (rFVIII) is the standard of care for severe hemophilia A in Sweden. The need for frequent injections with existing rFVIII products may, however, result in poor adherence to prophylaxis, leading to increased bleeding and long-term joint damage. Recombinant FVIIIFc (rFVIIIFc) is an extended half-life fusion protein which can offer prolonged protection and reduced dosing frequency. The objective of this study was to evaluate the cost-utility of prophylaxis with rFVIIIFc in severe hemophilia A from the perspective of the Swedish health system.

METHODS

A Markov model was built to estimate lifetime costs and benefits of prophylaxis with rFVIIIFc vs rFVIII products. Clinical outcomes were represented by annualized bleeding rate (ABR) and quality of life via disutility applied to bleeding events and injection frequency. Costs included the cost of FVIII for routine prophylaxis and bleed resolution. The pooled comparator was costed by weighting the cost of individual products by their market share.

RESULTS

In the base case, rFVIIIFc was dominant vs the pooled comparator. Savings of SEK 9.0 million per patient resulted from lower factor consumption for prophylaxis and bleed resolution. Fewer bleeds and reduced injection frequency yielded an estimated 0.59 quality-adjusted life years (QALYs). Results were sensitive to drug dosage and robust to variation in other parameters. Probabilistic sensitivity analysis suggested a greater than 85% probability of rFVIIIFc being cost-effective at a willingness-to-pay threshold of 500,000 SEK/QALY.

LIMITATIONS

Due to unavailibilty of patient-level data, treatment benefit was based on a non-adjusted indirect comparison. Dosing and treatment outcomes were assumed to persist over the model duration in the absence of long-term outcome data.

CONCLUSION

The results suggest that rFVIIIFc may be a cost-effective option for hemophilia A prophylaxis, generating greater quality of life and reduced costs for the Swedish payer compared to more frequently administered rFVIII alternatives.

Perioperative safety and hemostatic efficacy of Advate® in patients with hemophilia A in a postmarketing surveillance in Japan

Rurioctocog alfa (recombinant factor VIII: Advate^®) is available for the control of bleeding among patients with hemophilia A in Japan. To evaluate the perioperative safety and hemostatic efficacy of Advate^®, a postmarketing surveillance was conducted in Japanese patients undergoing surgery in a real-world setting. A total of 74 surgical procedures performed in 58 subjects aged 0-75 years, including three females, were studied. A hemostatic efficacy rating of "excellent" or "good" was reported in 73/74 surgical procedures (98.6%). Perioperative bleeding was successfully controlled by Advate^® in five subjects with positive FVIII inhibitors (2.4-9.1 BU/mL). Advate^® was administered at higher initial bolus doses (114-385 IU/kg) and at higher rates by subsequent initial continuous infusion (8.3-15 IU/kg/hour) in the five subjects with inhibitor than in the subjects without inhibitor (n = 47; mean initial bolus dose: 53.4 IU/kg; subsequent mean initial continuous infusion: 3.8 IU/kg/h). Adverse drug reactions were reported in 7/74 (9.5%) procedures, two of which were the development of de novo FVIII inhibitors. Overall, the perioperative use of Advate^® in a real-world setting was found to be safe and effective among Japanese patients with hemophilia A.

Lonoctocog alfa (rVIII-SingleChain) for the treatment of haemophilia A

INTRODUCTION

The administration of factor VIII (FVIII) concentrates on-demand or on long-term prophylaxis is the effective and safe standard of care of patients with hemophilia A (HA). Development of neutralizing antibodies against exogenous FVIII and the short half-life of the current available products remain major challenges. There is currently a great interest towards newer FVIII products with the goal of reducing the inhibitor risk and increasing the half-life. Area covered: In this review, the authors describe the efficacy and safety of rVIII-SingleChain (Lonoctocog alfa), the first and only single chain recombinant FVIII (rFVIII) molecule developed for the prevention and treatment of bleeding episodes in HA patients. The pre-clinical and clinical studies of rVIII-SingleChain as well as the results of the AFFINITY trial program in previously treated patients both adults and pediatric are presented and discussed. Expert opinion: The results from PTP studies document the efficacy and safety profile of the rVIII-SingleChain. However, even if rFVIII-SingleChain presents advantageous pharmacokinetic features compared to conventional rFVIII, it should not be considered as an EHL-FVIII while its immunogenicity is currently being studied in PUPs. The slightly better PK profile of rFVIII-SingleChain could however allow a small number of selected patients to be treated with a less intensive regimen.

Practical considerations in choosing a factor VIII prophylaxis regimen: Role of clinical phenotype and trough levels

Current therapy for haemophilia A is guided by severity of the disease, which in turn is best reflected in patients' endogenous factor VIII activity levels. For patients with severe haemophilia (particularly children), prophylaxis with continuous routine factor replacement has become standard of care in developed countries and is gradually becoming the standard of care in developing countries. The question arises then: what is an appropriate prophylaxis regimen to prevent bleeding events and arthropathy, while also maximizing patient quality of life and taking into consideration the costs of prophylaxis? Should all patients be treated with one standard, fixed prophylaxis regimen, or should prophylaxis be individualised for each patient? If so, what factors need to be considered in choosing the appropriate dose and frequency of factor administration? If prophylaxis is tailored to the individual patient, then patient-related factors (bleeding phenotype, activity profiles, age, joint status) and product-specific factors (half-life of the replacement factor in the individual patient) will determine the choice of regimen, whether it be a fixed-regimen prophylaxis or prophylaxis that is tailored to patient activity and bleeding risk. Regardless of the choice of prophylaxis regimen, for any regimen to be effective, adherence to therapy is key to optimising outcomes.

Evaluation of safety and effectiveness of factor VIII treatment in haemophilia A patients with low titre inhibitors or a personal history of inhibitor

There is no prospective evidence on inhibitor recurrence among haemophilia A patients with low titre inhibitors or history of inhibitors, and whether or how therapeutic choices affect the risk of recurrence. The aims of this study were to synthesise safety data in patients with moderate-severe haemophilia A and with low titre inhibitors or inhibitor history enrolled in the rAHF PFM (ADVATE) – Post-Authorization Safety Studies (ADVATE-PASS) international programme. The study was conducted in clinics participating to the ADVATE PASS programme. The patient population consisted of patients entering the studies with low titre (≤5 BU) inhibitors or a positive personal history of inhibitors. Patients on Immune Tolerance Induction at study entry were excluded. Primary outcome was new or recurrent inhibitor titre > 5 BU. Secondary outcomes were any increase of inhibitor titre not reaching 5 BU; any unexplained change in treatment regimen. Primary analysis was done by two-stage random effects meta-analysis. Secondary analysis was done by a hierarchical Bayesian random effects logistic model. A total of 219 patients from seven studies were included. Of these 214 (97.7 %) patients had been previously treated for more than 50 exposure days. Two hundred ten patients had positive history for inhibitors, nine a baseline measurable titre. No patient presented a primary outcome event (95 % confidence interval [CI] 0–1.6 %). Six patients with previous history developed a low titre recurrence (overall rate 2.2, 95 %CI 0–4.8 %). When any increase of inhibitor titre or any treatment change was accounted for, overall 3.7 % (95 % CI 0 %-8.0 %) of patients experienced the outcome. In conclusion, the observed rate of events does not support the definition of this population as at high risk for inhibitor development.

Clinical evaluation of glycoPEGylated recombinant FVIII: Efficacy and safety in severe haemophilia A

Turoctocog alfa pegol (N8-GP) is a novel glycoPEGylated extended half-life recombinant factor VIII (FVIII) product developed for prophylaxis and treatment of bleeds in patients with haemophilia A, to enable higher activity levels with less frequent injections compared with standard FVIII products. This phase III (NCT01480180), multinational, open-label, non-randomised trial evaluated the safety and clinical efficacy of N8-GP when administered for treatment of bleeds and for prophylaxis, in previously treated patients aged ≥12 years with severe haemophilia A. Patients were allocated to receive N8-GP for prophylaxis or on-demand treatment for up to 1.8 years. Patients on prophylaxis were administered one dose of 50 IU/kg of N8-GP every fourth day. Bleeds were treated with doses of 20–75 IU/kg. Total exposure to N8-GP in the trial was 14,114 exposure days (159 patient-years). For the prophylaxis arm (n=175), the median annualised bleeding rate (ABR) was 1.33 (interquartile range, 0.00–4.61), the mean ABR was 3.70 (95 % confidence interval 2.94–4.66) and 70 (40 %) patients had no bleeds during the trial. Across treatment arms, 83.6 % of bleeds resolved with one injection and 95.5 % with up to two injections. N8-GP had a favourable safety profile and was well tolerated. The frequency and types of adverse events reported were as expected in this population. One patient developed inhibitory antibodies against FVIII (≥0.6 Bethesda units [BU]) after 93 N8-GP exposure days. No clinically significant safety concerns were identified and N8-GP was effective for prophylaxis and treatment of bleeds in previously treated patients.

Long-term efficacy and safety of prophylaxis with recombinant factor VIII in Chinese pediatric patients with hemophilia A: a multi-center, retrospective, non-interventional, phase IV (ReCARE) study

BACKGROUND

The first recombinant factor VIII (rFVIII) product was launched in China in 2007. However, until now, no study has been conducted to describe the efficacy and safety of prophylaxis with rFVIII in Chinese pediatric patients with hemophilia A (HA).

OBJECTIVE

To summarize the efficacy and safety data on prophylaxis with rFVIII in Chinese pediatric patients with HA.

METHODS

ReCARE (Retrospective study in Chinese pediatric hemophilia A patients with rFVIII contained regular prophylaxis) was a retrospective study conducted in 12 hemophilia treatment centers (HTCs) across China. The primary endpoints included reduction in annualized bleeding rate (ABR); the secondary endpoints included evaluation of joint function (number and sites of target joints) using Gilbert score and Hemophilia Joint Health Score (HJHS), quality of life (QoL) and factors affecting treatment choices. Safety assessment of rFVIII was also conducted.

RESULTS

We analyzed a total of 183 male pediatric patients (mean age, 7.1 ± 4.23 years) who received prophylaxis between 1 November 2007 and 31 May 2013. Compared with baseline, prophylaxis with rFVIII significantly reduced overall annualized joint bleed rate (AJBR) (p < .001) and ABR (p < .001). Inhibitor formation was reported in 5 (2.7%) patients and hemarthrosis was reported in 1 patient. The mean number of target joints was positively related to age (p < .001) and weight (p = .003) at baseline. Responses from survey questionnaires reported that effective bleeding control, joint protection, improvement in quality of life, favorable medical insurance policies, and economic capability were reasons for choosing prophylaxis.

CONCLUSION

Prophylaxis with rFVIII reduced bleeding and number of target joints, even with a low-dose regimen, in Chinese pediatric patients with HA. Other than the efficacy and safety, factors such as poor disease control, improved economic stability and stable financial support made prophylaxis as an attractive treatment option. ClinicalTrials.gov ID: NCT02263066.

Efficacy and safety of full-length pegylated recombinant factor VIII with extended half-life in previously treated patients with hemophilia A: comparison of data between the general and Japanese study populations

Rurioctocog alfa pegol (BAX 855) is a novel third-generation recombinant factor VIII whose active ingredient is chemically modified with polyethylene glycol. A global multicenter phase 2/3 study of the product in 137 patients (including 11 patients from Japan) with severe hemophilia A aged 12-65 years, reported an extended half-life and a good tolerability profile, as well as a significantly lower annualized bleeding rate in the prophylactic treatment arm than in the on-demand treatment arm. Using descriptive statistics, a post hoc analysis was performed to compare the pharmacokinetics, safety, and efficacy profiles of the product in the Japanese subpopulation and the overall population. Extended half-life was demonstrated in the Japanese subpopulation. The mean [standard deviation (SD)] annualized bleeding rates in the prophylactic treatment arm were 3.7 (4.7) for the overall population (n = 120) and 4.0 (3.4) for the Japanese subpopulation (n = 11). The proportion of bleeds reported as excellent or good was 94.9% (149/157) in the overall population, whereas that in the Japanese subpopulation was 92.3% (12/13). No FVIII inhibition or anaphylactic reaction was reported in the Japanese subpopulation. The post hoc comparisons demonstrated similar pharmacokinetic, safety, and efficacy profiles between the overall population and the Japanese subpopulation.

Indirect comparisons of efficacy and weekly factor consumption during continuous prophylaxis with recombinant factor VIII Fc fusion protein and conventional recombinant factor VIII products

INTRODUCTION

Recombinant factor VIII (rFVIII) products with extended half-lives have the potential to improve adherence and outcomes in haemophilia beyond the results obtained with conventional rFVIII products.

AIM

In the absence of head-to-head comparisons, annualized bleed rates (ABRs) and weekly factor consumption with rFVIII Fc fusion protein (rFVIIIFc) and conventional rFVIII products were indirectly compared using studies of continuous prophylaxis.

METHODS

A systematic literature review was conducted to identify studies of rFVIII products for comparison with rFVIIIFc in the continuous prophylactic treatment of previously treated adolescents and adults with moderate and severe haemophilia A. Mean ABRs were compared between rFVIIIFc and individual rFVIII studies and between rFVIIIFc and a pooled measure for rFVIII estimated by meta-analysis. Comparisons of factor consumption were based on mean or median weekly factor consumption.

RESULTS

Results from seven studies of conventional rFVIII products (injections 2-4 times week^-1 ) were compared with rFVIIIFc (injections 1.4-2.4 times week^-1 ). The pooled mean ABR for rFVIII products was significantly higher compared with rFVIIIFc (difference = 2.0; P = 0.007). Compared with most rFVIII studies, the reported weekly factor consumption was lower with rFVIIIFc [mean differences = 15.5-21.8 IU kg^-1 week^-1 (17-26%); median differences = 12.7-29.8 IU kg^-1 week^-1 (16-37%)]. In one comparison, mean weekly factor consumption with rFVIII was significantly lower but mean ABR was significantly higher than rFVIIIFc.

CONCLUSION

Prophylaxis with rFVIIIFc may be associated with improved bleeding rates and lower weekly factor consumption than more frequently injected rFVIII products. Relative to rFVIII products with similar bleeding rates, results indicate that rFVIIIFc is associated with reduced weekly factor consumption while requiring fewer prescribed injections.

Natural history and clinical characteristics of inhibitors in previously treated haemophilia A patients: a case series

BACKGROUND

Development of inhibitors is the most serious complication in haemophilia A treatment. The assessment of risk for inhibitor formation in new or modified factor concentrates is traditionally performed in previously treated patients (PTPs). However, evidence on risk factors for and natural history of inhibitors has been generated mostly in previously untreated patients (PUPs). The purpose of this study was to examine cases of de novo inhibitors in PTPs reported in the scientific literature and to the EUropean HAemophilia Safety Surveillance (EUHASS) programme, and explore determinants and course of inhibitor development.

METHODS

We used a case series study design and developed a case report form to collect patient level data; including detection, inhibitor course, treatment, factor VIII products used and events that may trigger inhibitor development (surgery, vaccination, immune disorders, malignancy, product switch).

RESULTS

We identified 19 publications that reported 38 inhibitor cases and 45 cases from 31 EUHASS centres. Individual patient data were collected for 55/83 (66%) inhibitor cases out of 12 330 patients. The median (range) peak inhibitor titre was 4.4 (0.5-135.0), the proportion of transient inhibitors was 33% and only two cases of 12 undergoing immune tolerance induction failed this treatment. In the two months before inhibitor development, surgery was reported in nine (22%) cases, and high intensity treatment periods reported in seven (17%) cases.

CONCLUSIONS

By studying the largest cohort of inhibitor development in PTPs assembled to date, we showed that inhibitor development in PTPs, is on average, a milder event than in PUPs.

Bayesian approach to the assessment of the population-specific risk of inhibitors in hemophilia A patients: a case study

Background

Developing inhibitors is a rare event during the treatment of hemophilia A. The multifacets and uncertainty surrounding the development of inhibitors further complicate the process of estimating inhibitor rate from the limited data. Bayesian statistical modeling provides a useful tool in generating, enhancing, and exploring the evidence through incorporating all the available information.

Methods

We built our Bayesian analysis using three study cases to estimate the inhibitor rates of patients with hemophilia A in three different scenarios: Case 1, a single cohort of previously treated patients (PTPs) or previously untreated patients; Case 2, a meta-analysis of PTP cohorts; and Case 3, a previously unexplored patient population – patients with baseline low-titer inhibitor or history of inhibitor development. The data used in this study were extracted from three published ADVATE (antihemophilic factor [recombinant] is a product of Baxter for treating hemophilia A) post-authorization surveillance studies. Noninformative and informative priors were applied to Bayesian standard (Case 1) or random-effects (Case 2 and Case 3) logistic models. Bayesian probabilities of satisfying three meaningful thresholds of the risk of developing a clinical significant inhibitor (10/100, 5/100 [high rates], and 1/86 [the Food and Drug Administration mandated cutoff rate in PTPs]) were calculated. The effect of discounting prior information or scaling up the study data was evaluated.

Results

Results based on noninformative priors were similar to the classical approach. Using priors from PTPs lowered the point estimate and narrowed the 95% credible intervals (Case 1: from 1.3 [0.5, 2.7] to 0.8 [0.5, 1.1]; Case 2: from 1.9 [0.6, 6.0] to 0.8 [0.5, 1.1]; Case 3: 2.3 [0.5, 6.8] to 0.7 [0.5, 1.1]). All probabilities of satisfying a threshold of 1/86 were above 0.65. Increasing the number of patients by two and ten times substantially narrowed the credible intervals for the single cohort study (1.4 [0.7, 2.3] and 1.4 [1.1, 1.8], respectively). Increasing the number of studies by two and ten times for the multiple study scenarios (Case 2: 1.9 [0.6, 4.0] and 1.9 [1.5, 2.6]; Case 3: 2.4 [0.9, 5.0] and 2.6 [1.9, 3.5], respectively) had a similar effect.

Conclusion

Bayesian approach as a robust, transparent, and reproducible analytic method can be efficiently used to estimate the inhibitor rate of hemophilia A in complex clinical settings.

Therapeutic and routine prophylactic properties of rFactor VIII Fc (efraloctocog alfa, Eloctate®) in hemophilia A

rFVIIIFc (efraloctocog alfa, Eloctate^®) is an extended half-life (EHL) factor VIII licensed for use in patients with hemophilia A for prophylaxis and treatment of bleeding and surgical episodes. Pharmacokinetic studies in adults have shown a mean 1.5-fold increase in half-life compared to full-length factor VIII. When compared to adults, the half-life is decreased by 8% in adolescents between 12 and 17 years, by 18% in children 6 to <12 years, and by 33% in children between the ages of 2 and <6 years. There is a considerable interindividual variation in the prolongation of the half-life particularly in children and across the age groups, the range extending from no increase to a 2.5-fold increase. In addition to age, von willebrand factor (VWF) antigen level has demonstrated a significant impact on rFVIIIFc half-life, with higher VWF levels associated with greater prolongation of half-life. The pivotal and pediatric clinical trials have demonstrated the efficacy and safety of rFVIIIFc for use in regular prophylaxis and in management of bleeds and surgery. In these studies, just under half the participants showed a zero annualized bleed rate (ABR), and the median ABR (1.6 in the pivotal study for the individualized prophylaxis arm) showed a further decrease in the extension study. On average, the patients required fewer infusions (reduced by at least a third), and the mean weekly consumption seems to be in keeping with standard recombinant factor VIII. EHL rFVIIIFc has made decreased infusion frequency a possibility. However, the interindividual variability in dose and infusion frequency highlights the need for a personalized approach based on individual patient’s half-life and/or response to treatment.

The use of pharmacokinetics in dose individualization of factor VIII in the treatment of hemophilia A

INTRODUCTION

Hemophilia A is a bleeding disorder resulting from a lack of clotting factor VIII (FVIII), and treatment typically consists of prophylactic replacement of the deficient factor. However, high between subject variability precludes the development of a 'one size fits all' dosing strategy and necessitates an individualized approach. We sought to summarize the data on the pharmacokinetics of FVIII available as a basis for the development of population pharmacokinetic models to be used in dose tailoring. Areas covered: We reviewed the pharmacokinetics of FVIII as used for the treatment of hemophilia A, with a focus on the variability observed between patients and the application of pharmacokinetic methods to dose individualization. We also explored the covariates affecting pharmacokinetic parameters, the differences between plasma-derived and recombinant FVIII and the development of extended half-life products. Expert opinion: The pharmacokinetics of factor VIII in patients with hemophilia shows a high interpatient variability, and is affected by age, weight, level of von Willebrand factor, and blood group. A population approach to estimating individual pharmacokinetics is likely to provide the most successful strategy to tailor factor concentrate dosing to the individual needs and to ensure optimal patient outcomes, while also improving the cost-effectiveness of prophylactic replacement therapy.

Matching-adjusted indirect comparisons of efficacy of BAY 81-8973 vs two recombinant factor VIII for the prophylactic treatment of severe hemophilia A

BACKGROUND

No head-to-head trials comparing recombinant factor VIII (rFVIII) products currently exist. This was a matching-adjusted indirect comparison (MAIC) study of efficacy of BAY 81-8973 with antihemophilic factor (recombinant) plasma/albumin-free method (rAHF-PFM) and turoctocog alfa for the prophylaxis of severe hemophilia A.

METHODS

A systematic literature review was conducted to identify trials of rAHF-PFM and turoctocog alfa. Comparisons were conducted using BAY 81-8973 individual patient data (IPD) from LEOPOLD trials and published data from rAHF-PFM and turoctocog alfa trials. Differences in outcome reporting were reconciled using transformation of BAY 81-8973 IPD. Patients in pooled LEOPOLD trials were weighted to match baseline characteristics for rAHF-PFM or turoctocog alfa trials using MAICs. After matching, annualized bleed rates (ABRs) were compared using weighted t-tests.

RESULTS

Two rAHF-PFM trials and one turoctocog alfa trial were identified. In these trials, rFVIIIs were dosed thrice weekly or every other day; in LEOPOLD trials, BAY 81-8973 was dosed twice- or thrice weekly. Three MAICs were conducted because the two rAHF-PFM trials calculated ABRs differently, matching for age, race, and weight (turoctocog alfa only). BAY 81-8973 had similar ABR of all bleeds vs rAHF-PFM (two trials: 4.8 vs 6.3, 1.9 vs 1.8 [square root transform]) and lower ABR of spontaneous bleeds and trauma bleeds (2.6 vs 4.1, 2.1 vs 4.7; both P<0.05). BAY 81-8973 showed lower ABR of all bleeds and spontaneous bleeds vs turoctocog alfa (4.3 vs 6.5, 2.8 vs 4.3; both P<0.05) and similar ABR of trauma bleeds (1.5 vs 1.6). In subgroup analysis, twice-weekly BAY 81-8973 had similar ABRs of all bleeds, spontaneous bleeds, and trauma bleeds compared to rAHF-PFM and turoctocog alfa.

CONCLUSION

This indirect comparison found that prophylaxis with BAY 81-8973, even including the lower frequency of two times a week and lower factor VIII consumption, has efficacy comparable to rAHF-PFM and turoctocog alfa, which were dosed thrice weekly or every other day. The use of IPD enabled adjustments for differences in calculation of ABRs and population characteristics between trials.

Efficacy and safety of rVIII-SingleChain: results of a phase 1/3 multicenter clinical trial in severe hemophilia A

Recombinant VIII (rVIII)-SingleChain is a novel B-domain-truncated recombinant factor VIII (rFVIII), comprised of covalently bonded factor VIII (FVIII) heavy and light chains. It was designed to have a higher binding affinity for von Willebrand factor (VWF). This phase 1/3 study investigated the efficacy and safety of rVIII-SingleChain in the treatment of bleeding episodes, routine prophylaxis, and surgical prophylaxis. Participants were ≥12 years of age, with severe hemophilia A (endogenous FVIII <1%). The participants were allocated by the investigator to receive rVIII-SingleChain in either an on-demand or prophylaxis regimen. Of the 175 patients meeting study eligibility criteria, 173 were treated with rVIII-SingleChain, prophylactically (N = 146) or on-demand (N = 27). The total cumulative exposure was 14 306 exposure days (EDs), with 120 participants reaching ≥50 EDs and 52 participants having ≥100 EDs. Hemostatic efficacy was rated by the investigator as excellent or good in 93.8% of the 835 bleeds treated and assessed. Across all prophylaxis regimens, the median annualized spontaneous bleeding rate was 0.00 (Q1, Q3: 0.0, 2.4) and the median overall annualized bleeding rate (ABR) was 1.14 (Q1, Q3: 0.0, 4.2). Surgical hemostasis was rated as excellent/good in 100% of major surgeries by the investigator. No participant developed FVIII inhibitors. In conclusion, rVIII-SingleChain is a novel rFVIII molecule showing excellent hemostatic efficacy in surgery and in the control of bleeding events, low ABR in patients on prophylaxis, and a favorable safety profile in this large clinical study. This trial was registered at www.clinicaltrials.gov as #NCT01486927.

Pegylated, full-length, recombinant factor VIII for prophylactic and on-demand treatment of severe hemophilia A

Current management of hemophilia A includes prophylaxis with factor VIII (FVIII) replacement every 2 to 3 days. BAX 855, Baxalta's pegylated full-length recombinant FVIII (rFVIII), was designed to increase half-life and, thus, reduce the frequency of prophylactic infusions while maintaining hemostatic efficacy. BAX 855 was evaluated in previously treated patients with severe hemophilia A who were aged 12 to 65 years. A phase 1 study compared the pharmacokinetic (PK) profile of BAX 855 with that of licensed rFVIII (Advate). In a pivotal study, the annualized bleeding rate (ABR), PK parameters, and efficacy of bleeding treatment were assessed. In the phase 1 study, the mean half-life (T1/2) and the mean residence time of BAX 855 compared with Advate were 1.4- to 1.5-fold higher. These results were confirmed in the pivotal study. The pivotal study met its primary endpoint: Prophylaxis with BAX 855 resulted in an ABR that was significantly lower than half the ABR of on-demand treatment (P < .0001). The median ABR was 1.9, and 39.6% of compliant subjects had no bleeding episodes during prophylaxis, whereas subjects treated on-demand had a median ABR of 41.5. BAX 855 was also efficacious for the treatment of bleeding episodes, with 95.9% of bleeding episodes treated with 1 to 2 infusions and 96.1% having efficacy ratings of excellent/good. No FVIII inhibitory antibodies or safety signals were identified. These studies provide evidence that BAX 855 was safe and efficacious for on-demand treatment and prophylaxis administered twice weekly in patients with hemophilia A. The trials were registered at www.clinicaltrials.gov as #NCT01736475 and #NCT01599819.