Plasma and albumin-free recombinant factor VIII: pharmacokinetics, efficacy and safety in previously treated pediatric patients

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.

Clot formation and fibrinolysis assays reveal functional differences among hemostatic agents in hemophilia A plasma

Background

Measuring the activity of hemostatic agents used to treat hemophilia A often requires drug-specific assays. In vitro assays show hemophilic clots have abnormal characteristics, including prolonged clotting time and decreased resistance to fibrinolysis. The ability of certain agents to correct these parameters in vitro is associated with hemostatic efficacy in vivo.

Objectives

To compare effects of established and emerging hemostatic agents on clot formation and fibrinolysis in hemophilia A plasma.

Methods

Pooled and individual hemophilia A platelet-poor plasmas were spiked with replacement (recombinant factor VIII [rFVIII], PEGylated rFVIII, polysialylated rFVIII, and porcine rFVIII) or bypassing (emicizumab, rFVIIa, and activated prothrombin complex concentrate) products. Effects on tissue factor-initiated clot formation and fibrinolysis were measured by turbidity.

Results

Compared to normal pooled plasma, hemophilia-pooled plasma showed reduced clot formation and increased fibrinolysis, and all replacement agents improved these characteristics. rFVIII and PEGylated rFVIII produced similar effects at similar concentrations, whereas polysialylated rFVIII produced slightly higher and porcine rFVIII slightly lower effects at these concentrations. Bypassing agents enhanced clot formation and stability, but patterns differed from replacement agents. The clotting rate showed a concentration-response relationship for all agents. High concentrations of all products produced effects that exceeded the normal range in at least some parameters. Responses of individual donors varied, but all agents improved clot formation and stability in all donors tested.

Conclusion

Clotting and fibrinolysis assays reveal hemostatic effects of replacement and bypassing therapies at clinically relevant concentrations. These assays may help characterize hemostatic agents and optimize dosing.

Etranacogene dezaparvovec for the treatment of adult patients with severe and moderately severe hemophilia B

INTRODUCTION

Etranacogene dezaparvovec is the first gene therapy approved for treatment of adults with severe and moderately severe hemophilia B.

AREAS COVERED

This review describes the results of the clinical trial program of AMT-060 and etranacogene dezaparvovec, outlining the pharmacokinetic, clinical efficacy and safety data. With the entry of etranacogene dezaparvovec into the market, this review summarizes the treatment landscape in hemophilia B and discusses the current unknowns in the field.

EXPERT OPINION

Gene therapy appears to be a feasible option for adults with severe and moderately severe hemophilia B. Etranacogene dezaparvovec enables most patients to reach stable factor IX (FIX) levels after a single intravenous infusion, eliminating the need for regular prophylaxis; thus, drastically reducing treatment burden and avoiding variable bleeding risk owing to fluctuating FIX activity levels. Efficacy of etranacogene dezaparvovec has been demonstrated even in the presence of preexisting neutralizing antibodies (up to a titer of 1:678), with a relative low risk of transaminitis and its associated potential loss of transgene expression. However, long-term data are required to ascertain the durability of FIX levels achieved and safety. The cost-effectiveness and adoption of innovative payment models for reimbursement are key in choosing gene therapy over existing treatments.

Dosing for Personalized Prophylaxis in Hemophilia A Highly Varies on the Underlying Population Pharmacokinetic Models

BACKGROUND

Model-informed personalized prophylaxis with factor VIII (FVIII) replacement therapy aimed at higher trough levels is becoming indispensable for patients with severe hemophilia A. This study aimed to identify the most suitable population pharmacokinetic (PK) models for personalized prophylaxis using various FVIII products and 2 clinical assays and to implement the most suitable one in open-access software.

METHODS

Twelve published population PK models were systematically compared to predict the time above target (TaT) for a reference dosing occasion. External validation was performed using a 5-point PK data from 39 adult patients with hemophilia A with FVIII measured by chromogenic substrate (CSA) and 1-stage assays (OSAs) using NONMEM under 3 different conditions: a priori (with all FVIII samples blinded), a posteriori (with 1 trough sample), and general model fit (with all FVIII samples including the reference dosing occasion provided).

RESULTS

On average, the baseline covariate models overpredicted TaT (a priori; bias -3.8 hours to 49.6 hours). When additionally including 1 previous trough FVIII sample before the reference dosing occasion (a posteriori), only 50% of the models improved in bias (-1.0 hours to 36.5 hours) and imprecision (22.4 hours and 60.7 hours). Using all the time points (general model fit), the models accurately predicted (individual TaT less than ±12 hours compared with the reference) 62%-90% and 33%-74% of the patients using CSA and OSA data, respectively. Across all scenarios, predictions using CSA data were more accurate than those using the OSA data.

CONCLUSIONS

One model performed best across the population (bias: -3.8 hours a priori, -1.0 hours a posteriori , and 0.6 hours general model fit ) and acceptably predicted 44% (a priori) to 90% ( general model fit ) of the patients. To allow the community-based evaluation of patient-individual FVIII dosing, this model was implemented in the open-access model-informed precision dosing software "TDMx."

Cost-Effectiveness Analysis of rFVIIIFc Versus Contemporary rFVIII Treatments for Patients with Severe Hemophilia A Without Inhibitors in the United States

BACKGROUND

A range of treatments for patients with severe hemophilia A (HA) have been developed over the last decade, allowing for reduced frequency of administration and improved outcomes (joint health and breakthrough bleeding rates). While clinically effective, the cost effectiveness of these treatments has not been established.

OBJECTIVE

This study presents a cost-effectiveness analysis of contemporary rFVIII treatments for severe HA patients without inhibitors.

METHODS

A published semi-Markov model was used to compare three different prophylaxis regimens: (1) extended half-life (EHL) recombinant Factor VIII (rFVIII) Fc-fusion protein (rFVIIIFc, Eloctate^®, Sanofi), (2) EHL PEGylated rFVIII (PEG-rFVIII, Adynovate^®, Takeda), and (3) standard half-life (SHL) rFVIII (antihemophilic factor [recombinant], Advate^®, Takeda), used as a proxy for all SHL rFVIII treatments. Acquisition costs were included based on published dosing and weight data. Benefits were incorporated through published annualized bleeding rates, rates of target joint development/resolution, and improvements in the modified hemophilia joint health score. Results were presented as total, discounted costs, and quality-adjusted life-years (QALYs).

RESULTS

rFVIIIFc was shown to provide the most QALYs (27.922) compared with both PEG-rFVIII (27.454) and SHL rFVIII (27.071), at lower costs. Discounted lifetime costs were estimated at US$18.235m (rFVIIIFc), US$20.198m (PEG-rFVIII), and US$18.285m (SHL rFVIII), and were predominantly affected by model settings related to acquisition costs, patient weight, and dosing.

CONCLUSIONS

rFVIIIFc may offer a cost-effective option for severe HA patients. Uncertainties owing to the limited evidence base is the main limitation of the study.

Emerging drugs for hemophilia A: insights into phase II and III clinical trials

INTRODUCTION

Hemophilia is a lifelong, genetic-bleeding disorder, which inadequately treated results in permanent joint damage. It is characterized by spontaneous and trauma-related bleeding episodes. In the last 50 years, treatment has seen dramatic improvements which have improved the quality of life of persons with hemophilia.

AREAS COVERED

This review will provide a summary of current pharmacological approaches for hemophilia A as well as discuss novel agents which are either approved recently or in phase II-III clinical trials, plasma-derived and recombinant factor VIII (FVIII) products, extended half-life FVIII products, bypassing agents and non-replacement therapies.

EXPERT OPINION

Novel therapies are already changing the way that hemophilia A is managed, and as more new therapies get approved, there will be a revolution in the management of this serious condition. Clinicians will have both the opportunities as well as the challenges of incorporating such new technologies into clinical practice.

Clinical Analysis of Hospitalized Patients with Hemophilia A: Single-hemophilia Treatment Center Experience in Korea over 10 years

Background

There is lack of data on admitted hemophilia patients in Korea. For this reason, this study was intended to analyze the hospitalization data of hemophilia patients in a regional Hemophilia Treatment Center (HTC) for the first time in Korea.

Methods

In this retrospective study, we surveyed hospitalized patients with Hemophilia A (HA) in a HTC for 14 years. Medical records of these hemophiliacs were reviewed and data regarding demographic characteristics, cause of admissions and their outcomes in each patient were obtained. In addition, the data of admitted days, type and amount of Coagulation factor concentrate (CFC) used, treatments other than CFC infusion during the admission days were also obtained from the medical record of each patient.

Results

A total 107 patients with hemophilia A were admitted during 14 years. Annual rate of admission of patients with HA was 8%. Mean age on admission was 29.63±19.51 years old and mean admission days were 11.28±5.46 days. Most admissions were occurred in severe and moderate hemophilia patients. The most common cause of admission was bleed control followed by surgery and other reasons. With modified WFH CFC supplementation guideline, all the bleeds were successfully controlled and all surgeries were also successfully conducted with less total CFC consumption compared to the consumed dose of other reports.

Conclusion

These results suggest that it is necessary to develop more specified regimens different from WFH guidelines of CFC supplementation for admitted Korean patients with hemophilia A.

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.

Pharmacokinetic study of Kovaltry in thirty-five pediatric patients aged <12 years with severe hemophilia A

BACKGROUND

Kovaltry (BAY81-8973) is an unmodified full-length factor VIII (FVIII) concentrate that enhances the pharmacokinetic (PK) profiles as compared to some other standard half-life time FVIII concentrates. However, the PK of Kovaltry in haemophiliac patients aged <12 years has not been reported previously.

AIM

To investigate the pharmacokinetics and clinical outcomes of Kovaltry in 35 paediatric patients aged <12 years.

METHODS

A total of 35 boys with severe haemophilia A were enrolled from August 2019 to May 2020 in Beijing Children's Hospital. After 72-hour washout, PK tests were performed post-infusion of 50 IU/kg Kovaltry in a five-timepoint assay. WinNonlin software was used to generate individual PK parameters. The dose, frequency and bleeding details were collected within the first 6 months after switching to Kovaltry from other FVIII concentrates.

RESULTS

Compared to the blood group O, patients with blood group non-O showed longer mean half-life (t_1/2 ) (p < .01), lower mean clearance (CL) (p = .01) and similar in vivo recovery (IVR) (p = .51). Higher von Willebrand factor antigen (VWF:Ag) level was correlated to longer t_1/2 (p < .0001) and lower CL (p < .01). IVR was correlated to body mass index (BMI) (p < .0001). Patients with trough level >3 IU/dL demonstrated lower annual bleeding rate (ABR) (p < .01), annual joint bleeding rate (AJBR) (p < .01) and annual spontaneous bleeding rate (ASBR) (p < .01).

CONCLUSION

This study firstly reported the PK profiles of Kovaltry in 35 paediatric patients <12 years old. The great inter-individual variability of PK parameters was also confirmed in these patients. VWF:Ag and blood group were major influencing factors of t_1/2 and CL of Kovaltry, while BMI was a vital predictor for IVR. Patients with high trough FVIII level in routine prophylaxis had reduced bleeding rates.

Pharmacokinetic variability of factor VIII concentrates in Chinese pediatric patients with moderate or severe hemophilia A

IMPORTANCE

The use of factor VIII (FVIII) concentrates under pharmacokinetic (PK) guidance has become the main approach for treatment of hemophilia. However, limited PK research has been conducted in Chinese pediatric patients.

OBJECTIVE

To investigate the PK parameters of various FVIII concentrates in Chinese pediatric patients.

METHODS

Seventy-nine patients were enrolled (28 treated with Kogenate FS®, 23 treated with Advate ®, and 28 treated with GreenMono™). All enrolled patients participated in single-dose PK analysis after at least a 3-day washout period. Blood samples were collected predose, as well as at 1 h, 9 h, 24 h, and 48 h after infusion; FVIII levels were measured using a one-stage clotting assay. von Willebrand Factor Antigen (VWF:Ag) levels and blood types were also determined. PK parameters were evaluated by WAPPS-Hemo.

RESULTS

Mean values of terminal elimination half-life time (t1/2) for the Kogenate FS®, Advate®, and GreenMono™ FVIII groups were 12.24 h, 10.18 h, and 9.62 h; median clearance values were 4.16, 6.23, and 5.11 mL·kg-1·h-1; and median in vivo recovery values were 1.97, 1.55, and 1.61 IU/dL per IU/kg. Longer t1/2, higher in vivo recovery, and lower clearance were observed in patients with higher VWF:Ag level who were treated with recombinant concentrates.

INTERPRETATION

Chinese pediatric patients with hemophilia had FVIII PK characteristics similar to those previously observed in non-Chinese children, including large variation among individuals. VWF:Ag level and FVIII brand were associated with differences in FVIII PK. Thus, PK-guided dosing should be used to optimize individualized therapy in Chinese children.

Safety evaluation of emicizumab prophylaxis in individuals with haemophilia A

INTRODUCTION

Emicizumab is a bispecific-humanized monoclonal antibody that improves hemostasis by bridging activated factor IX and factor X to substitute for the function of missing activated FVIII. It is an alternative to prophylaxis with factor VIII replacement and is associated with improved outcomes in individuals with hemophilia A with and without inhibitors.

AREAS COVERED

Emicizumab is efficacious in reducing bleeding events when compared to on-demand treatment and factor-based prophylaxis. Except for the few thrombotic microangiopathy and thrombotic event cases mainly seen in the HAVEN 1 trial, emicizumab has an overall excellent safety profile with minimal side effects.

EXPERT OPINION

Knowledge gaps include the efficacy and safety of emicizumab in younger age groups and those with mild or moderate hemophilia A. Future directions for research include exploring the risk of inhibitor recurrence in patients with a history of high titer inhibitor who have been successfully tolerized, who switch from factor prophylaxis to emicizumab, as well as conducting 'real world studies' to evaluate the patient's perception of emicizumab in regard to ease and tolerability in order to optimize individualized treatment plans.

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.

Efficacy and safety of fibrinogen concentrate for on-demand treatment of bleeding and surgical prophylaxis in paediatric patients with congenital fibrinogen deficiency

Background

Congenital fibrinogen deficiency (CFD) is a rare, inherited disorder affecting normal blood clotting function, where patients can experience severe and/or frequent bleeding episodes (BEs). Treatment with human fibrinogen concentrate (HFC) can prevent/arrest bleeding. There is a need for more data on the efficacy, pharmacokinetics (PK) and safety of HFC treatment in paediatric patients with CFD.

Methods

Haemostatic efficacy of HFC (Fibryga^®, Octapharma AG) for on‐demand treatment of bleeding and surgical prophylaxis in patients <12 years old was assessed by investigators and an Independent Data Monitoring and Endpoint Adjudication Committee (IDMEAC) based on an objective 4‐point efficacy scale. Maximum clot firmness (MCF; surrogate marker of haemostatic efficacy), single‐dose PK and safety were also assessed.

Results

Of 14 patients receiving HFC (median [range] age 6.0 years [1.0–10.0]), eight received HFC for 10 BEs, three for surgical prophylaxis and 13 for PK. The IDMEAC rated haemostatic efficacy as 100% successful for on‐demand BE treatment (95% CI 69.15–100.00) and surgical prophylaxis (95% CI 29.24–100.00). After a mean first dose of 70.78 mg/kg for BEs, mean (±SD) MCF significantly increased from pre‐treatment to 1‐hour post‐infusion (3.3 mm [±1.77]; P = 0.0002), coinciding with haemostatic efficacy. PK parameters were favourable. Two possibly related adverse events occurred, including one serious (portal vein thrombosis). No allergic/hypersensitivity reactions or deaths were observed.

Conclusion

HFC treatment for on‐demand treatment of BEs and surgical prophylaxis was efficacious for this ultra‐rare paediatric population with congenital afibrinogenaemia and showed a favourable PK and safety profile.

BIVV001 Fusion Protein as Factor VIII Replacement Therapy for Hemophilia A

BACKGROUND

Factor VIII replacement products have improved the care of patients with hemophilia A, but the short half-life of these products affects the patients' quality of life. The half-life of recombinant factor VIII ranges from 15 to 19 hours because of the von Willebrand factor chaperone effect. BIVV001 (rFVIIIFc-VWF-XTEN) is a novel fusion protein designed to overcome this half-life ceiling and maintain high sustained factor VIII activity levels. Data are lacking on the safety and pharmacokinetics of single-dose BIVV001.

METHODS

In this phase 1-2a open-label trial, we consecutively assigned 16 previously treated men (18 to 65 years of age) with severe hemophilia A (factor VIII activity, <1%) to receive a single intravenous injection of recombinant factor VIII at a dose of 25 IU per kilogram of body weight (lower-dose group) or 65 IU per kilogram (higher-dose group). This injection was followed by a washout period of at least 3 days. The patients then received a single intravenous injection of BIVV001 at the same corresponding dose of either 25 IU or 65 IU per kilogram. Adverse events and pharmacokinetic measurements were assessed.

RESULTS

No inhibitors to factor VIII were detected and no hypersensitivity or anaphylaxis events were reported up to 28 days after the injection of single-dose BIVV001. The geometric mean half-life of BIVV001 was three to four times as long as that of recombinant factor VIII (37.6 hours vs. 9.1 hours in the lower-dose group and 42.5 vs. 13.2 hours in the higher-dose group); the area under the curve (AUC) for product exposure was six to seven times as great in the two dose groups (4470 hours vs. 638 hours × IU per deciliter in the lower-dose group and 12,800 hours vs. 1960 hours × IU per deciliter in the higher-dose group). After the injection of BIVV001 in the higher-dose group, the mean factor VIII level was in the normal range (≥51%) for 4 days and 17% at day 7, which suggested the possibility of a weekly interval between treatments.

CONCLUSIONS

In a small, early-phase study involving men with severe hemophilia A, a single intravenous injection of BIVV001 resulted in high sustained factor VIII activity levels, with a half-life that was up to four times the half-life associated with recombinant factor VIII, an increase that could signal a new class of factor VIII replacement therapy with a weekly treatment interval. No safety concerns were reported during the 28-day period after administration. (Funded by Sanofi and Sobi; ClinicalTrials.gov number, NCT03205163.).

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.

An evaluation of the safety and efficacy of turoctocog alfa for hemophilia A

Introduction: Hemophilia A is an inherited disorder that is characterized by decreased or absent factor (F)VIII and an increased risk of bleeding. Clinical presentation of the severe form of the disease includes spontaneous bleeding into the joints and muscles, while patients with milder forms usually exhibit trauma-associated bleeding. The treatment of hemophilia aims to prevent bleeding. A number of clotting FVIII concentrates are available for managing hemophilia A, which have different safety and efficacy characteristics. Advancements in biotechnology have enabled development of recombinant factor concentrates, which thus minimize the risk of transmitting infectious diseases. Turoctocog alfa (NovoEight®, Novo Nordisk A/S, Bagsvaerd, Denmark) was the first third-generation B-domain truncated recombinant FVIII.Areas covered: The manuscript describes the characteristics of turoctocog alfa, as well as its efficacy and safety for prophylaxis and on-demand treatment for patients with severe hemophilia A without inhibitors.Expert opinion: In clinical trials, turoctocog alfa has demonstrated very good efficacy and safety for the prophylaxis and on-demand treatment of hemophilia A patients, as well as high hemostatic activity during surgery and in managing bleeding episodes. Post-marketing studies and real-life data are anticipated to further reinforce the value of long-term prophylaxis, and estimate the incidence of inhibitors to FVIII.

Cost-Effectiveness Analysis of Recombinant Factor VIII Fc-Fusion Protein (rFVIIIFc) for the Treatment of Severe Hemophilia A in Italy Incorporating Real-World Dosing and Joint Health Data

BACKGROUND

Patients with severe hemophilia A (SHA) in Italy are routinely treated with standard half-life recombinant factor VIII (rFVIII) products. rFVIII Fc-fusion protein (rFVIIIFc) is an extended half-life rFVIII product that enables less frequent administration than rFVIII, which may support improved adherence. Available data indicate low breakthrough bleed rates and potentially improved long-term joint health for patients treated with rFVIIIFc prophylaxis.

OBJECTIVE

This study assessed the cost effectiveness of rFVIIIFc versus rFVIII from an Italian healthcare perspective.

METHODS

A Semi-Markov model was constructed to assess the lifetime costs and benefits of rFVIII and rFVIIIFc prophylaxis. rFVIII product acquisition costs from a published Italian database were included for both prophylaxis and the resolution of breakthrough bleeding. Clinical outcomes within the model were determined based on published annualized bleeding rates and literature regarding the development of target joints (TJs) as the incidence of bleeds and TJs is associated with impaired health-related quality of life. Cost effectiveness was assessed using cost per quality-adjusted life-year (QALY) gained.

RESULTS

Compared with rFVIII, rFVIIIFc was associated with a per-patient cost saving of approximately €1.3 million and QALY gains of 0.39 over a lifetime horizon. Sensitivity analyses considering alternative efficacy, dosing, and structural assumptions each showed that rFVIIIFc dominated rFVIII (i.e., provided more QALYs at a reduced cost).

CONCLUSIONS

This cost-effectiveness analysis demonstrated that rFVIIIFc may offer a cost-effective treatment option for patients with SHA in Italy.

Factor VIII prophylaxis effects outweigh other hemostasis contributors in predicting severe haemophilia A joint outcomes

INTRODUCTION

The Joint Outcome Study (JOS) demonstrated that previously untreated children with severe haemophilia A treated with prophylactic factor VIII (FVIII) concentrate had superior joint outcomes at age 6 years compared to those children treated episodically for bleeding. However, variation in joint outcome within each treatment arm was not well explained.

AIM

In this study, we sought to better understand variation in joint outcomes at age 6 years in participants of the JOS.

METHODS

We evaluated the influence of FVIII half-life, treatment adherence, constitutional coagulant and anticoagulant proteins, and global assays on joint outcomes (number of joint bleeds, total number of bleeds, total MRI score and joint physical exam score). Logistic regression was used to evaluate the association of variables with joint failure status on MRI, defined as presence of subchondral cyst, surface erosion or joint-space narrowing. Each parameter was also correlated with each joint outcome using Spearman correlations.

RESULTS

Prophylaxis treatment arm and FVIII trough were each found to reduce risk of joint failure on univariate logistic regression analysis. When controlling for treatment arm, FVIII trough was no longer significant, likely because of the high level of covariation between these variables. We found no consistent correlation between any laboratory assay performed and any joint outcome parameter measured.

CONCLUSION

In the JOS, the effect of prescribed prophylactic FVIII infusions on joint outcome overshadowed the contribution of treatment adherence, FVIII half-life, global assays of coagulation and constitutional coagulation proteins. (ClinicalTrials.gov number, NCT00207597).

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.

Pharmacokinetic Studies of Factor VIII in Chinese Boys with Severe Hemophilia A: A Single-Center Study

Background:

Although much attention has been paid to the pharmacokinetics (PKs) of different factor VIII (FVIII) concentrates in persons with hemophilia A (HA), limited information is available in young boys with severe HA. In this study, we aimed to assess the PK parameters of FVIII products in boys with severe HA in China.

Methods:

A total of 36 boys (plasma-derived [pd]-FVIII, n = 15; recombinant [r] FVIII, n = 21) were enrolled between January 2015 and May 2016 in Beijing Children's Hospital. PK characteristics of FVIII products were studied according to a reduced 4-sampling time point design (1 h, 9 h, 24 h, and 48 h postinfusion).

Results:

The mean FVIII half-life (t_1/2) was 10.99 ± 3.45 h (range 5.52–20.02 h), the mean in vivo recovery (IVR) was 2.01 ± 0.42 IU/dl per IU/kg (range 1.24–3.02 IU/dl per IU/kg) and mean clearance (CL) of FVIII is 4.34 ± 1.58 ml·kg⁻¹·h⁻¹ (range 2.29–7.90 ml·kg⁻¹·h⁻¹). We also analyzed the influence of several parameters that potentially modulate FVIII PK. The age was closely associated with FVIII half-life (R²= 0.32, P < 0.01). The t_1/2 of FVIII increased by 0.59 h per year. Besides age, von Willebrand factor antigen (VWF:Ag) also was associated with FVIII half-life (R²= 0.52, P < 0.01). Patients with blood Group O had a shorter FVIII half-life than patients with non-O blood group (9.40 ± 0.68 h vs. 12.3 ± 0.79 h, t = 2.70, P = 0.01). The FVIII IVR correlated with age (R²= 0.21, P < 0.01) and VWF:Ag level (R²= 0.28, P < 0.01). CL rates were faster in young patients and in those with low-VWF:Ag levels. CL rates of FVIII are higher in blood Group O versus non-blood Group O persons (5.02 ± 0.38 vs. 4.00 ± 0.32 ml·kg⁻¹·h⁻¹, t = 2.53, P = 0.02).

Conclusions:

Chinese boys with severe HA have similar PK values to other ethnic groups and large differences in FVIII PK between individual patients. Age, blood group, and VWF:Ag levels are important determining factors for FVIII CL.

Obesity in the global haemophilia population: prevalence, implications and expert opinions for weight management

Overweight and obesity may carry a significant disease burden for patients with haemophilia (PWH), who experience reduced mobility due to joint inflammation, muscle dysfunction and haemophilic arthropathy. This review aimed to define the prevalence and clinical impact of overweight/obesity in the global population of PWH. A detailed literature search pertaining to overweight/obesity in haemophilia in the last 15 years (2003-2018) was conducted, followed by a meta-analysis of epidemiological data. The estimated pooled prevalence of overweight/obesity in European and North American PWH was 31%. Excess weight in PWH is associated with a decreased range in motion of joints, accelerated loss of joint mobility and increase in chronic pain. Additionally, the cumulative disease burden of obesity and haemophilia may impact the requirement for joint surgery, occurrence of perioperative complications and the prevalence of anxiety and depression that associates with chronic illness. Best practice guidelines for obesity prevention and weight management, based on multidisciplinary expert perspectives, are considered for adult and paediatric PWH. Recommendations in the haemophilia context emphasize the importance of patient education and tailoring engagement in physical activity to avoid the risk of traumatic bleeding.

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.

Pediatric physiology in relation to the pharmacokinetics of monoclonal antibodies

INTRODUCTION

Dose design for pediatric trials with monoclonal antibodies (mAbs) is often extrapolated from the adult dose according to weight, age, or body surface area. While these methods account for the size differences between adults and children, they do not account for the maturation of processes that may play a key role in the pharmacokinetics and/or pharmacodynamics of mAbs. With the same weight-based dose, infants and young children typically receive lower plasma exposures when compared to adults. Areas covered: The mechanistic features of mAb distribution, elimination, and absorption are explored in detail and literature-based hypotheses are generated to describe their age-dependence. This knowledge can be incorporated into a physiologically based pharmacokinetic (PBPK) modeling approach to pediatric dose determination. Expert opinion: As data from pediatric clinical trials become increasingly available, we have the opportunity to reflect on the physiologic drivers of pharmacokinetics, safety, and efficacy in children with mathematical models. A modeling approach that accounts for the age-related features of mAb disposition can be used to derive first-in-pediatric doses, design optimal sampling schemes for children in clinical trials and even explore new pharmacokinetic end-points as predictors of safety and efficacy in children.

Factor VIII products and inhibitor development in previously treated patients with severe or moderately severe hemophilia A: a systematic review

Essentials Data on product-related immunogenicity in previously treated haemophilia A patients is scarce. A systematic review and meta-analysis of all currently available evidence was conducted. The overall incidence rate was 2.06 per 1000 person-years (95% confidence interval: 1.06-4.01). Some recombinant factor VIII products were associated with increased immunogenicity.

SUMMARY

Background Patients with severe hemophilia A who have been treated extensively with factor VIII products have a low but potentially serious risk of inhibitor development. It is unknown why these patients develop inhibitors, and data on product-related immunogenicity are scarce. Aims To summarize the currently available evidence on the relationship between inhibitor development and recombinant FVIII product type in previously treated patients (PTPs) with severe hemophilia A. Methods Longitudinal studies were included that reported on de novo inhibitor formation in patients with baseline FVIII activity levels of < 0.02 IU mL-1 who had been treated with FVIII for at least 50 days. Pooled incidence rates of inhibitor development according to product types were calculated with a random intercept Poisson regression model. Results Forty-one independent cohorts were included; 39 patients developed de novo inhibitors during 19 157 person-years of observation. The overall incidence rate was 2.06 per 1000 person-years, with a 95% confidence interval (CI) of 1.06-4.01. According to product type, the pooled incidence rates were 0.99 (95% CI 0.37-2.70) per 1000 person-years for patients treated with Advate, 5.86 (95% CI 0.25-134.92) per 1000 person-years for those treated with Kogenate/Helixate, 1.35 (95% CI 0.66-2.77) per 1000 person-years for those treated with Kogenate FS/Helixate NexGen, 12.05 (95% CI 1.53-94.78) per 1000 person-years for those treated with Refacto, and 4.64 (95% CI 0.82-26.43) per 1000 person-years for those treated with Refacto AF. Conclusion These results suggest that some products may be associated with increased immunogenicity. However, the low incidence of inhibitors in PTPs and the differences in study design may cause significant variation in estimates of risk.

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.

Clinical experience with moroctocog alfa (AF-CC) in younger paediatric patients with severe haemophilia A: Two open-label studies

INTRODUCTION

The pharmacokinetics (PK), efficacy and safety of moroctocog alfa (AF-CC) have been demonstrated in haemophilia A patients aged ≥6 years.

AIM

These studies aimed to further describe moroctocog alfa (AF-CC) experience in paediatric patients (<12 years) with severe haemophilia A (FVIII:C < 1%).

METHODS

Two prospective, open-label studies enrolled patients aged <12 years: one study with 37 previously treated patients (PTPs) and another with 23 previously untreated patients (PUPs). All patients initially received 50 IU/kg of moroctocog alfa (AF-CC) to evaluate either recovery alone, or with other PK parameters (6 to <12 years) before continuing treatment for 100 exposure days (EDs) or 24 months.

RESULTS

At baseline, mean (±SD) recovery ranged between 1.32 ± 0.65 (PUPs aged <2 years) and 2.13 ± 0.82 (PTPs aged 6 to <12 years). The mean (±SD) half-life was 9.12 ± 1.94 hours in PTPs aged 6 to <12 years. No new safety signals were detected in either study, 2 transient lower titre inhibitors occurred in PTPs while 8 inhibitors (3 low and 5 high titre) were detected in PUPs. Most bleeding episodes resolved with one infusion (94% [893/954]). The annualised bleeding rate (ABR) in the PTP study was 27.5 and 4.2 for patients reporting an on-demand and routine prophylaxis regimen at baseline, respectively. In the PUP study, the overall ABR was 5.9.

CONCLUSION

Moroctocog alfa (AF-CC) had expected PK findings (lower recovery in young children compared with older children) along with being safe and efficacious in a population of young severe haemophilia A patients.

Long-term tolerability, immunogenicity and efficacy of Nuwiq® (human-cl rhFVIII) in children with severe haemophilia A

INTRODUCTION

Nuwiq^® (human-cl rhFVIII, simoctocog alfa) is a 4th generation recombinant human FVIII, without chemical modification or fusion with any other protein, produced in a human cell line.

AIM/METHODS

This study (GENA-13) was an extension of the GENA-03 study in which previously treated children aged 2-12 years with severe haemophilia A received Nuwiq^® prophylaxis for ≥6 months. GENA-13 examined long-term tolerability, immunogenicity and efficacy of Nuwiq^® prophylaxis in children.

RESULTS

Of 59 patients enrolled in GENA-03, 49 continued Nuwiq^® prophylaxis in GENA-13 for a median (range) of 30.0 (9.5-52.0) months. No patient withdrew due to drug-related adverse events or developed inhibitors. Only 2 of 20 518 infusions were associated with possibly related adverse events (dyspnoea, fever). The estimated annualized bleeding rate (ABR) was 0.67 (95% CI: 0.44, 1.02) for spontaneous and 2.88 (95% CI: 1.86, 4.46) for all bleeds. Younger children (2-5 years) had lower ABRs than children aged 6-12 years. Annualized bleeding rates were reduced in GENA-13 vs GENA-03, especially for spontaneous bleeds in younger children (71% reduction; ABR ratio 0.29 [95% CI: 0.11, 0.74]). Nuwiq^® efficacy was rated as excellent/good in the treatment of 83.0% of 305 evaluated breakthrough bleeds. Surgical prophylaxis with Nuwiq^® was rated as excellent for all 17 assessed procedures.

CONCLUSION

Long-term treatment with Nuwiq^® for the prevention of bleeds in children with severe haemophilia A was well tolerated, effective and reduced spontaneous bleeding by up to 70% compared with GENA-03.

Low incidence of factor VIII inhibitors in previously untreated patients with severe haemophilia A treated with octanate® : Final report from a prospective study

INTRODUCTION

Octanate^® is a human, plasma-derived, von Willebrand factor-stabilized coagulation factor VIII (FVIII) concentrate with demonstrated haemostatic efficacy in previously treated patients with haemophilia A.

AIM

This prospective, open-label study aimed to assess the immunogenicity of octanate^® in previously untreated patients (PUPs).

METHODS

The study monitored development of FVIII inhibitors in 51 PUPs. Tolerability, viral safety, FVIII recovery and efficacy of octanate^® for the prevention and treatment of bleeds and in surgical procedures were also assessed.

RESULTS

Five (9.8%) of the 51 patients developed inhibitors during the study, 4 of which (7.8%) were high titre. Three inhibitor cases (5.9%) were considered clinically relevant; 2 were transient inhibitors that disappeared during regular octanate^® treatment without a change in dose or treatment frequency. Amongst 45 patients with FVIII:C <1% at baseline and who received ≥20 exposure days (EDs) or had <20 EDs but developed an inhibitor, inhibitor incidence was 11.1% (6.7% clinically relevant). All clinically relevant inhibitors developed within 20 EDs of on-demand treatment. No inhibitors developed in PUPs receiving prophylaxis. All patients who developed inhibitors had either intron 22 inversions or large deletions. Irrespective of the reason for administration, haemostatic efficacy was rated as "excellent" in 99.6% of all infusions (4700 of 4717 infusions), and no complications were reported in 23 surgical procedures. Mean incremental in vivo recovery was 2.0%/IU/kg (±0.7) and 1.9%/IU/kg (±0.5) for the first and second assessments, respectively. Tolerability was rated "very good" in 99.9% of infusions.

CONCLUSION

In PUPs with severe haemophilia A, octanate^® demonstrated haemostatic efficacy with a low rate of inhibitor development.

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.

Efficacy and safety of prophylaxis with once-weekly BAY 79–4980 compared with thrice-weekly rFVIII-FS in haemophilia A patients

The benefits of prophylaxis of haemophilia A patients regarding joint health and quality-of-life are well established. However, adherence to an up to every-other-day infusion regimen is a barrier to widespread adoption of prophylaxis. BAY 79–4980 is an investigational drug consisting of rFVIII-FS (sucrose-formulated recombinant FVIII) reconstituted with liposome solvent. Previous clinical studies showed extended protection from bleeding after a single injection of BAY 79–4980 (13.3 ± 6.2 days) compared with rFVIII-FS (7.2 ± 1.7 days). The effect of once-a-week prophylaxis with BAY 79–4980 (35 IU/kg) compared with three times-per-week rFVIII-FS (25 IU/kg) in previously treated, severe haemophilia A patients was evaluated in a 52-week, double-blind, two-arm, randomised, controlled study. The primary and secondary endpoints were protection from total bleeds and joint bleeds, respectively. Short- and long-term safety and tolerability of BAY 79–4980 including effects on lipid levels were assessed. A total of 139 and 131 subjects were evaluable for safety and efficacy analyses, respectively. A large difference in efficacy between treatment groups was observed with 72.1% (49/68) in the rFVIII-FS control group demonstrating <9 bleeds/year compared with 38.1% (24/63) of BAY 79–4980-treated subjects. A similar difference was seen in annualised joint bleeds, with 43 subjects (63.2%) in the control group demonstrating <5 joint bleeds/year compared with 24 subjects (38.1%) treated with BAY 79–4980. The distribution of bleeds seven days post-prophylactic treatment with BAY 79–4980 showed that 61% of bleeds occurred after day 4 post dosing. There were no safety concerns identified. The investigational treatment arm was prematurely discontinued due to failure to achieve the primary endpoint.

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.

An Open-label, Single-dose, Pharmacokinetic Study of Factor VIII Activity After Administration of Moroctocog Alfa (AF-CC) in Male Chinese Patients With Hemophilia A

PURPOSE

Hemophilia A represents up to 80% of all hemophilia cases in China. In patients with this condition, bleeding can be prevented and controlled by administering clotting factor VIII (FVIII). Since their initial availability, recombinant FVIII products have undergone several iterations to enhance their safety. Moroctocog alfa albumin-free cell culture (AF-CC) is among the third generation of recombinant FVIII products and received regulatory approval in China in August 2012. The present study characterizes the single-dose pharmacokinetic parameters of FVIII activity (FVIII:C) after administration of moroctocog alfa (AF-CC) in male Chinese patients with hemophilia A.

METHODS

This multicenter, open-label, single-dose study enrolled 13 male Chinese patients diagnosed with severe hemophilia A (FVIII:C <1%) and a history of at least 150 exposure-days to any FVIII-containing product. Eligible patients received a single dose of moroctocog alfa (AF-CC) 50 IU/kg IV within 10 minutes. Blood samples were collected within 2 hours before administration and through 72 hours after dosing.

FINDINGS

Pharmacokinetic parameters were assessed based on FVIII:C and were analyzed by age groups: ages 6 to <12 years (n = 3) and ≥12 years (n = 10). The mean plasma concentration-time profile for FVIII:C activity was consistently lower in patients aged 6 to <12 years compared with those aged ≥12 years. Geometric AUC_0-∞ and C_max were approximately 57% and 28% lower in the younger patients relative to the older patients, respectively. A total of 4 adverse events occurred in 4 patients. Low-titer, transient FVIII inhibitors were observed in 2 patients and were considered serious adverse events. Neither case resulted in clinical manifestations nor required treatment.

IMPLICATIONS

This is the first report of the pharmacokinetic parameters of FVIII:C after moroctocog alfa (AF-CC) in an all-Chinese population of males with hemophilia A. The pharmacokinetic profile in older patients was similar to that previously reported with recombinant FVIII products in studies with a predominantly white population; younger patients had reduced exposure to FVIII:C. The single doses of moroctocog alfa (AF-CC) were well tolerated; 2 cases of transient, low-titer FVIII inhibitor development were observed. ClinicalTrials.gov identifier: NCT02461992.

Pharmacokinetics, Safety, and Efficacy of Recombinant Factor VIII Fc Fusion Protein: A Practical Review

Prophylaxis for hemophilia A with conventional factor VIII (FVIII) products requires frequent intravenous dosing, which may reduce adherence. Recombinant factor VIII Fc fusion protein (rFVIIIFc) has a prolonged half-life compared with conventional rFVIII, and has demonstrated safety and efficacy for the prevention and treatment of bleeding episodes in phase 3 studies of patients with severe hemophilia A. Most subjects experienced reduced prophylactic dosing frequency with rFVIIIFc compared with prestudy FVIII; the median total weekly prophylactic consumption was comparable. No subjects developed inhibitors. These results suggest that prophylaxis with rFVIIIFc in patients with hemophilia A may allow less frequent prophylactic dosing while maintaining efficacy, with comparable prophylactic consumption.

Safety, efficacy and pharmacokinetics of rVIII-SingleChain in children with severe hemophilia A: results of a multicenter clinical trial

Essentials rVIII-SingleChain is a novel recombinant factor VIII with covalently bonded heavy and light chains. Efficacy, safety and pharmacokinetics were studied in pediatric patients with severe hemophilia A. Across all prophylaxis regimens, the median annualized spontaneous bleeding rate was 0.00. rVIII-SingleChain showed excellent hemostatic efficacy and a favorable safety profile.

SUMMARY

Background rVIII-SingleChain is a novel B-domain truncated recombinant factor VIII (rFVIII) comprised of covalently bonded FVIII heavy and light chains, demonstrating a high binding affinity to von Willebrand factor. Objectives This phase III study investigated the safety, efficacy and pharmacokinetics of rVIII-SingleChain in previously treated pediatric patients < 12 years of age with severe hemophilia A. Patients/Methods Patients could be assigned to prophylaxis or on-demand therapy by the investigator. For patients assigned to prophylaxis, the treatment regimen and dose were based on the bleeding phenotype. For patients receiving on-demand therapy, dosing was guided by World Federation of Hemophilia recommendations. The primary endpoint was treatment success, defined as a rating of 'excellent' or 'good' on the investigator's clinical assessment of hemostatic efficacy for all treated bleeding events. Results The study enrolled 84 patients (0 to < 6 years, n = 35; ≥ 6 to < 12 years, n = 49); 81 were assigned to prophylaxis and three to an on-demand regimen. Patients accumulated a total of 5239 exposure days (EDs), with 65 participants reaching > 50 EDs. In the 347 bleeds treated and evaluated by the investigator, hemostatic efficacy was rated as excellent or good in 96.3%. The median annualized spontaneous bleeding rate was 0.00 (Q1, Q3: 0.00, 2.20), and the median annualized bleeding rate was 3.69 (Q1, Q3: 0.00, 7.20) across all prophylaxis regimens. No participant developed an inhibitor. Conclusions rVIII-SingleChain is a novel rFVIII molecule showing excellent hemostatic efficacy and a favorable safety profile in a clinical study in children < 12 years of age with severe hemophilia A.

Medical co-morbidities of patients with haemophilia: pain, obesity and hepatitis C

Clinical care of patients with haemophilia (PWH) has progressed rapidly over the past decade. Current therapy has allowed patients with haemophilia to live longer and many patients are now experiencing the co-morbidities of the general population. In this review article, we focus on three common diseases states that affect PWH: chronic pain, obesity and hepatitis C. Pain has been a co-morbidity for many years and PWH often have unusual needs for chronic pain relief compared to the general population. Obesity is not only increasing in the general population but also in patients with hereditary bleeding disorders. The co-morbidity of obesity not only causes increased pain progression and joint damage but also affects the dosing of factor concentrates. Finally, hepatitis C is known to have infected the majority of patients who received non-virally inactivated pooled factor concentrates in the past. New treatment regimens have been developed that allow the nearly uniform cure of chronic hepatitis C with a short course of oral medications.

BAY 81-8973, a full-length recombinant factor VIII: manufacturing processes and product characteristics

BAY 81-8973 (Kovaltry^® , Bayer, Berkeley, CA, USA) is an unmodified, full-length recombinant human factor VIII (FVIII) approved for prophylaxis and on-demand treatment of bleeding episodes in patients with haemophilia A. The BAY 81-8973 manufacturing process is based on the process used for sucrose-formulated recombinant FVIII (rFVIII-FS), with changes and enhancements made to improve production efficiency, further augment pathogen safety, and eliminate animal- and human-derived raw materials from the production processes. The baby hamster kidney cell line used for BAY 81-8973 was developed by introducing the gene for human heat shock protein 70 into the rFVIII-FS cell line, a change that improved cell line robustness and productivity. Pathogen safety was enhanced by including a 20-nm filtration step, which can remove viruses, transmissible spongiform encephalopathy agents and potential protein aggregates. No human- or animal-derived proteins are added to the cell culture process, purification or final formulation. The BAY 81-8973 manufacturing process results in a product of enhanced purity with a consistently high degree of sialylation of N-linked glycans on the molecular surface. The innovative manufacturing techniques used for BAY 81-8973 yield an effective rFVIII product with a favourable safety profile for treatment of haemophilia A.