Two-Year Outcomes of Valoctocogene Roxaparvovec Therapy for Hemophilia A.

BACKGROUND: Valoctocogene roxaparvovec delivers a B-domain-deleted factor VIII coding sequence with an adeno-associated virus vector to prevent bleeding in persons with severe hemophilia A. The findings of a phase 3 study of the efficacy and safety of valoctocogene roxaparvovec therapy evaluated after 52 weeks in men with severe hemophilia A have been published previously. METHODS: We conducted an open-label, single-group, multicenter, phase 3 trial in which 134 men with severe hemophilia A who were receiving factor VIII prophylaxis received a single infusion of 6×1013 vector genomes of valoctocogene roxaparvovec per kilogram of body weight. The primary end point was the change from baseline in the annualized rate of treated bleeding events at week 104 after receipt of the infusion. The pharmacokinetics of valoctocogene roxaparvovec were modeled to estimate the bleeding risk relative to the activity of transgene-derived factor VIII. RESULTS: At week 104, a total of 132 participants, including 112 with data that were prospectively collected at baseline, remained in the study. The mean annualized treated bleeding rate decreased by 84.5% from baseline (P<0.001) among the participants. From week 76 onward, the trajectory of the transgene-derived factor VIII activity showed first-order elimination kinetics; the model-estimated typical half-life of the transgene-derived factor VIII production system was 123 weeks (95% confidence interval, 84 to 232). The risk of joint bleeding was estimated among the trial participants; at a transgene-derived factor VIII level of 5 IU per deciliter measured with chromogenic assay, we expected that participants would have 1.0 episode of joint bleeding per year. At 2 years postinfusion, no new safety signals had emerged and no new serious adverse events related to treatment had occurred. CONCLUSIONS: The study data show the durability of factor VIII activity and bleeding reduction and the safety profile of valoctocogene roxaparvovec at least 2 years after the gene transfer. Models of the risk of joint bleeding suggest that the relationship between transgene-derived factor VIII activity and bleeding episodes is similar to that reported with the use of epidemiologic data for persons with mild-to-moderate hemophilia A. (Funded by BioMarin Pharmaceutical; GENEr8-1 ClinicalTrials.gov number, NCT03370913.).

Gene Therapy with Etranacogene Dezaparvovec for Hemophilia B.

BACKGROUND: Moderate-to-severe hemophilia B is treated with lifelong, continuous coagulation factor IX replacement to prevent bleeding. Gene therapy for hemophilia B aims to establish sustained factor IX activity, thereby protecting against bleeding without burdensome factor IX replacement. METHODS: In this open-label, phase 3 study, after a lead-in period (≥6 months) of factor IX prophylaxis, we administered one infusion of adeno-associated virus 5 (AAV5) vector expressing the Padua factor IX variant (etranacogene dezaparvovec; 2×1013 genome copies per kilogram of body weight) to 54 men with hemophilia B (factor IX activity ≤2% of the normal value) regardless of preexisting AAV5 neutralizing antibodies. The primary end point was the annualized bleeding rate, evaluated in a noninferiority analysis comparing the rate during months 7 through 18 after etranacogene dezaparvovec treatment with the rate during the lead-in period. Noninferiority of etranacogene dezaparvovec was defined as an upper limit of the two-sided 95% Wald confidence interval of the annualized bleeding rate ratio that was less than the noninferiority margin of 1.8. Superiority, additional efficacy measures, and safety were also assessed. RESULTS: The annualized bleeding rate decreased from 4.19 (95% confidence interval [CI], 3.22 to 5.45) during the lead-in period to 1.51 (95% CI, 0.81 to 2.82) during months 7 through 18 after treatment, for a rate ratio of 0.36 (95% Wald CI, 0.20 to 0.64; P<0.001), demonstrating noninferiority and superiority of etranacogene dezaparvovec as compared with factor IX prophylaxis. Factor IX activity had increased from baseline by a least-squares mean of 36.2 percentage points (95% CI, 31.4 to 41.0) at 6 months and 34.3 percentage points (95% CI, 29.5 to 39.1) at 18 months after treatment, and usage of factor IX concentrate decreased by a mean of 248,825 IU per year per participant in the post-treatment period (P<0.001 for all three comparisons). Benefits and safety were observed in participants with predose AAV5 neutralizing antibody titers of less than 700. No treatment-related serious adverse events occurred. CONCLUSIONS: Etranacogene dezaparvovec gene therapy was superior to prophylactic factor IX with respect to the annualized bleeding rate, and it had a favorable safety profile. (Funded by uniQure and CSL Behring; HOPE-B ClinicalTrials.gov number, NCT03569891.).

Emicizumab prophylaxis in infants with hemophilia A (HAVEN 7): primary analysis of a phase 3b open-label trial.

ABSTRACT: Subcutaneous emicizumab enables prophylaxis for people with hemophilia A (HA) from birth, potentially reducing risk of bleeding and intracranial hemorrhage (ICH). HAVEN 7 (NCT04431726) is the first clinical trial of emicizumab dedicated to infants, designed to investigate the efficacy, safety, pharmacokinetics, and pharmacodynamics of emicizumab in those aged ≤12 months with severe HA without factor VIII (FVIII) inhibitors. Participants in this phase 3b trial received emicizumab 3 mg/kg maintenance dose every 2 weeks for 52 weeks and are continuing emicizumab during the 7-year long-term follow-up. Efficacy end points included annualized bleed rate (ABR): treated, all, treated spontaneous, and treated joint bleeds. Safety end points included adverse events (AEs), thromboembolic events (TEs), thrombotic microangiopathies (TMAs), and immunogenicity (anti-emicizumab antibodies [ADAs] and FVIII inhibitors). At primary analysis, 55 male participants had received emicizumab (median treatment duration: 100.3; range, 52-118 weeks). Median age at informed consent was 4.0 months (range, 9 days to 11 months 30 days). Model-based ABR for treated bleeds was 0.4 (95% confidence interval, 0.30-0.63), with 54.5% of participants (n = 30) having zero treated bleeds. No ICH occurred. All 42 treated bleeds in 25 participants (45.5%) were traumatic. Nine participants (16.4%) had ≥1 emicizumab-related AE (all grade 1 injection-site reactions). No AE led to treatment changes. No deaths, TEs, or TMAs occurred. No participant tested positive for ADAs. Two participants were confirmed positive for FVIII inhibitors. This primary analysis of HAVEN 7 indicates that emicizumab is efficacious and well tolerated in infants with severe HA without FVIII inhibitors.

Valoctocogene Roxaparvovec Gene Therapy for Hemophilia A.

BACKGROUND: Valoctocogene roxaparvovec (AAV5-hFVIII-SQ) is an adeno-associated virus 5 (AAV5)-based gene-therapy vector containing a coagulation factor VIII complementary DNA driven by a liver-selective promoter. The efficacy and safety of the therapy were previously evaluated in men with severe hemophilia A in a phase 1-2 dose-escalation study. METHODS: We conducted an open-label, single-group, multicenter, phase 3 study to evaluate the efficacy and safety of valoctocogene roxaparvovec in men with severe hemophilia A, defined as a factor VIII level of 1 IU per deciliter or lower. Participants who were at least 18 years of age and did not have preexisting anti-AAV5 antibodies or a history of development of factor VIII inhibitors and who had been receiving prophylaxis with factor VIII concentrate received a single infusion of 6×1013 vector genomes of valoctocogene roxaparvovec per kilogram of body weight. The primary end point was the change from baseline in factor VIII activity (measured with a chromogenic substrate assay) during weeks 49 through 52 after infusion. Secondary end points included the change in annualized factor VIII concentrate use and bleeding rates. Safety was assessed as adverse events and laboratory test results. RESULTS: Overall, 134 participants received an infusion and completed more than 51 weeks of follow-up. Among the 132 human immunodeficiency virus-negative participants, the mean factor VIII activity level at weeks 49 through 52 had increased by 41.9 IU per deciliter (95% confidence interval [CI], 34.1 to 49.7; P<0.001; median change, 22.9 IU per deciliter; interquartile range, 10.9 to 61.3). Among the 112 participants enrolled from a prospective noninterventional study, the mean annualized rates of factor VIII concentrate use and treated bleeding after week 4 had decreased after infusion by 98.6% and 83.8%, respectively (P<0.001 for both comparisons). All the participants had at least one adverse event; 22 of 134 (16.4%) reported serious adverse events. Elevations in alanine aminotransferase levels occurred in 115 of 134 participants (85.8%) and were managed with immune suppressants. The other most common adverse events were headache (38.1%), nausea (37.3%), and elevations in aspartate aminotransferase levels (35.1%). No development of factor VIII inhibitors or thrombosis occurred in any of the participants. CONCLUSIONS: In patients with severe hemophilia A, valoctocogene roxaparvovec treatment provided endogenous factor VIII production and significantly reduced bleeding and factor VIII concentrate use relative to factor VIII prophylaxis. (Funded by BioMarin Pharmaceutical; GENEr8-1 ClinicalTrials.gov number, NCT03370913.).

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

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

A novel gene editing lexicon strategy for the haemophilia community: Research plan for development and preliminary results.

INTRODUCTION: Despite the progress in gene editing platforms like CRISPR/Cas9 with the potential to transform the standard of care for haemophilia, the language used to explain and discuss gene editing is not aligned across the haemophilia community. Here, we present the objective and rationale for developing a clear, consistent, and globally aligned gene editing lexicon to address these communication gaps. METHODS: Effectively communicating complex gene editing concepts requires a clear and consistent vocabulary. Through collaboration with a diversity of haemophilia stakeholders, our main goal is to develop an accurate, informative lexicon which avoids overpromising or highly technical terminology. Using an innovative process, representatives from several patient and scientific haemophilia organizations and select biotechnology companies will develop and refine language concepts to be tested with approximately seventy participants across the United States of America, United Kingdom, and Germany. Participants will include lived experience experts (LEEs) and haematologists. The process will be overseen by the Lexicon Steering Committee of global experts from leading scientific and patient organizations in the haemophilia and gene editing fields. RESULTS: Initial feedback provided a robust foundation and rationale for building clear, consistent language around gene editing. This lexicon development framework will allow for increased understanding across the haemophilia community, including the development of valid informed consent and shared decision-making materials. CONCLUSION: Results provide important building blocks for stimuli development and highlight the need for a novel gene editing lexicon. In the next phase, language stimuli will be tested with LEEs and haematologists to better understand audience preferences and help shape the final lexicon.

Macrophage Galactose Lectin Contributes to the Regulation of FVIII (Factor VIII) Clearance in Mice-Brief Report.

BACKGROUND: Although most plasma FVIII (Factor VIII) circulates in complex with VWF (von Willebrand factor), a minority (3%-5%) circulates as free-FVIII, which is rapidly cleared. Consequently, 20% of total FVIII may be cleared as free-FVIII. Critically, the mechanisms of free-FVIII clearance remain poorly understood. However, recent studies have implicated the MGL (macrophage galactose lectin) in modulating VWF clearance. METHODS: Since VWF and FVIII share similar glycosylation, we investigated the role of MGL in FVIII clearance. FVIII binding to MGL was assessed in immunosorbent and cell-based assays. In vivo, FVIII clearance was assessed in MGL1-/- and VWF-/-/FVIII-/- mice. RESULTS: In vitro-binding studies identified MGL as a novel macrophage receptor that binds free-FVIII in a glycan-dependent manner. MGL1-/- and MGL1-/- mice who received an anti-MGL1/2 blocking antibody both showed significantly increased endogenous FVIII activity compared with wild-type mice (P=0.036 and P<0.0001, respectively). MGL inhibition also prolonged the half-life of infused FVIII in FVIII-/- mice. To assess whether MGL plays a role in the clearance of free FVIII in a VWF-independent manner, in vivo clearance experiments were repeated in dual VWF-/-/FVIII-/- mice. Importantly, the rapid clearance of free FVIII in VWF-/-/FVIII-/- mice was significantly (P=0.012) prolonged in the presence of anti-MGL1/2 antibodies. Finally, endogenous plasma FVIII levels in VWF-/- mice were significantly increased following MGL inhibition (P=0.016). CONCLUSIONS: Cumulatively, these findings demonstrate that MGL plays an important role in regulating macrophage-mediated clearance of both VWF-bound FVIII and free-FVIII in vivo. We propose that this novel FVIII clearance pathway may be of particular clinical importance in patients with type 2N or type 3 Von Willebrand disease.

Long-term outcomes with emicizumab prophylaxis for hemophilia A with or without FVIII inhibitors from the HAVEN 1-4 studies.

Prophylaxis with emicizumab, a subcutaneously administered bispecific humanized monoclonal antibody, promotes effective hemostasis in persons with hemophilia A (PwHAs). The primary efficacy, safety, and pharmacokinetics of emicizumab were reported previously, but long-term data were limited. Here, data from 401 pediatric and adult PwHAs with/without factor VIII (FVIII) inhibitors who were enrolled in the phase 3 HAVEN 1, HAVEN 2, HAVEN 3, and HAVEN 4 studies (NCT02622321, NCT02795767, NCT02847637, NCT03020160) have been pooled to establish a long-term efficacy, safety, and pharmacokinetics profile. Across a median efficacy period of 120.4 weeks (interquartile range, 89.0-164.4) (data cutoff 15 May 2020), the model-based treated annualized bleed rate (ABR) was 1.4 (95% confidence interval [CI], 1.1-1.7). ABRs declined and then stabilized at <1 in an analysis of 24-week treatment intervals; at weeks 121 to 144 (n = 170), the mean treated ABR was 0.7 (95% CI, 0-5.0). During weeks 121 to 144, 82.4% of participants had 0 treated bleeds, 97.6% had ≤3 treated bleeds, and 94.1% reported no treated target joint bleeds. Bleeding into target joints decreased substantially. Emicizumab was well tolerated, and no participant discontinued because of adverse events beyond the 5 previously described. This data cutoff includes the previously reported 3 thrombotic microangiopathies (one in the PwHA with fatal rectal hemorrhage) and 2 thromboembolic events, all associated with activated prothrombin complex concentrate use, as well as a myocardial infarction and a venous device occlusion. With 970.3 patient-years of exposure, emicizumab prophylaxis maintained low bleed rates in PwHAs of all ages with/without FVIII inhibitors and remains well tolerated, with no new safety concerns identified.

The changing treatment landscape in haemophilia: from standard half-life clotting factor concentrates to gene editing.

Congenital haemophilia A (factor VIII deficiency) and B (factor IX deficiency) are X-linked bleeding disorders. Replacement therapy has been the cornerstone of the management of haemophilia, aiming to reduce the mortality and morbidity of chronic crippling arthropathy. Frequent intravenous injections are burdensome and costly for patients, consequently with poor adherence and restricted access to therapy for many patients worldwide. Bioengineered clotting factors with enhanced pharmacokinetic profiles can reduce the burden of treatment. However, replacement therapy is associated with a risk for inhibitor development that adversely affects bleeding prevention and outcomes. Novel molecules that are subcutaneously delivered provide effective prophylaxis in the presence or absence of inhibitors, either substituting for the procoagulant function of clotting factors (eg, emicizumab) or targeting the natural inhibitors of coagulation (ie, antithrombin, tissue factor pathway inhibitor, or activated protein C). The ultimate goal of haemophilia treatment would be a phenotypical cure achievable with gene therapy, currently under late phase clinical investigation.

Gene therapy: Practical aspects of implementation.

The first wave of gene therapies for haemophilia submitted for regulatory review utilize a liver-directed approach in which a functional gene copy of factor VIII (FVIII) or factor IX (FIX) is packaged inside a recombinant adeno-associated viral vector (rAAV). Following a single treatment event, these particles are taken up into liver cells, where the rAAV uncoats and delivers the DNA to the nucleus of the cell, where genetic elements that accompany the gene allow for efficient expression and secretion of FVIII or FIX protein into the plasma. An immune response to the vector capsid has been manifest by elevations in common liver enzymes that must be diligently followed postinfusion for weeks and months afterward and if signs of toxicity appear, will trigger a course of immunosuppression. Despite this, the studies have shown that this works in the great majority of individuals and the immunosuppression course is either avoided or short-lived for many. Optimal outcomes in the haemophilia population will be dependent on proper screening assessment and maintenance of liver health prior to consideration of gene therapy, close short-term follow up and implementation of immunomodulatory strategies to identify and manage liver toxicity and preserve durable transgene expression. This review proposes best practices to assist clinical teams with overcoming the challenges this platform of therapy poses to the traditional clinical care models and infrastructure within the haemophilia treatment centres (HTCs) who will be coordinating the patient's journey through this potentially transformative therapy.

Eptacog beta efficacy and safety in the treatment and control of bleeding in paediatric subjects (<12 years) with haemophilia A or B with inhibitors.

INTRODUCTION: Eptacog beta is a new recombinant activated human factor VII bypassing agent approved in the United States for the treatment and control of bleeding in patients with haemophilia A or B with inhibitors 12 years of age or older. AIM: To prospectively assess in a phase 3 clinical trial (PERSEPT 2) eptacog beta efficacy and safety for treatment of bleeding in children <12 years of age with haemophilia A or B with inhibitors. METHODS: Using a randomised crossover design, subjects received initial doses of 75 or 225 µg/kg eptacog beta followed by 75 µg/kg dosing at predefined intervals (as determined by clinical response) to treat bleeding episodes (BEs). Treatment success criteria included a haemostasis evaluation of 'excellent' or 'good' without use of additional eptacog beta, alternative haemostatic agent or blood product, and no increase in pain following the first 'excellent' or 'good' assessment. RESULTS: Treatment success proportions in 25 subjects (1-11 years) who experienced 546 mild or moderate BEs were 65% in the 75 µg/kg initial dose regimen (IDR) and 60% in the 225 µg/kg IDR 12 h following initial eptacog beta infusion. By 24 h, the treatment success proportions were 97% for the 75 µg/kg IDR and 98% for the 225 µg/kg IDR. No thrombotic events, allergic reactions, neutralising antibodies or treatment-related adverse events were reported. CONCLUSION: Both 75 and 225 µg/kg eptacog beta IDRs provided safe and effective treatment and control of bleeding in children <12 years of age.

Pain and functional disability amongst adults with moderate and severe haemophilia from the Irish personalised approach to the treatment of haemophilia (iPATH) study.

OBJECTIVES: To establish the prevalence of pain and functional disability in Irish adults with moderate and severe haemophilia, and to examine demographic and lifestyle influences. METHODS: Males ≥18 years with moderate or severe haemophilia participated. Pain and function were examined using the PROBE questionnaire. RESULTS: Of 49 participants [median age 44 (IQR 32, 52) years], most had severe haemophilia (Factor VIII = 30; Factor IX = 13) and were on regular prophylaxis (88%). Those with moderate haemophilia (Factor VIII = 5; Factor IX = 1) treated on demand (12%). Acute (72%) and chronic pain (71%), functional difficulties (58%), and analgesic requirements (92%) were prevalent. Age was significantly associated with more advanced haemophilic arthropathy (p = .002), chronic pain (p = .029) and functional difficulties (p = .036). Adults who reported chronic pain commenced prophylaxis significantly later in life [32 (20, 51) vs. 8 (1, 23) years; p = .004]. Physical activity was significantly lower in those with functional difficulties (p < .05). A disparity between self-perceived 'target joints' and clinically defined target joints was also identified (76% vs. 23%). CONCLUSION: Haemophilic arthropathy, pain and functional disability were prevalent amongst Irish adults with moderate and severe haemophilia. Age-dependent lifestyle, analgesic and treatment influences on pain and function warrant further investigation.

New therapies for hemophilia.

Hemophilia A (HA) and hemophilia B (HB) are the most common severe bleeding disorders. Replacement therapy, providing the missing coagulation factor, has been the mainstay of treatment both prophylactically and to treat bleeding. Despite widespread availability of safe and effective replacement therapy, patients with HA and HB continue to experience a tremendous burden of treatment, breakthrough bleeding, and progressive joint disease, as well as high rates of inhibitor development. These remaining challenges are now being addressed by incredible advances in bioengineering. Recombinant bioengineering has led to replacement therapies with easier modes of administration, decreased immunogenicity, increased efficacy, and extended half-lives. Emicizumab, a bispecific antibody that acts as a substitutive therapy for HA, has been approved for patients with and without inhibitors. Novel compounds are in development to exploit the natural balance of hemostasis by targeting the natural anticoagulants protein C, protein S, tissue factor pathway inhibitor, and antithrombin. The substitution and rebalancing therapies provide an opportunity for steady-state hemostatic control without exposure to immunogenic clotting factor proteins. As such, they may have broader applications outside those being investigated in the clinical trial programs.

Delivering on the promise of gene therapy for haemophilia.

The promise of gene therapy is a single treatment ('one and done') that leads to steady-state expression of endogenous factor VIII or factor IX sufficient to achieve a functional cure (free of recurrent haemophilic bleeding) if not normalized haemostasis. The elimination of the need for continued prophylaxis, or factor replacement following trauma or prior to surgery would lead to annual cost savings. Such optimized health and well-being would be reaching a level of health equity that was unimaginable several decades ago. 'Before anything else, preparation is the key to success'-Alexander Graham Bell. This quote from the famous inventor, scientist and engineer highlights that, although we currently stand on the threshold of this achievement, delivering on this promise will require broad-based multistakeholder preparation (scientists, manufacturers, federal regulators, health technology assessors, persons with haemophilia, national advocacy groups and multidisciplinary healthcare teams) with a focused emphasis on education, approval of safe and effective therapies, removal of barriers to access and excellence in clinical delivery.

Management of COVID-19-associated coagulopathy in persons with haemophilia.

INTRODUCTION: The SARS-CoV-2 coronavirus-induced infection (COVID-19) can be associated with a coagulopathy mainly responsible for pulmonary microvasculature thrombosis and systemic thromboembolic manifestations. The pathophysiology and management of the COVID-19 coagulopathy are likely more complex in patients with inherited bleeding diseases such as haemophilia. These individuals might indeed present with both bleeding and thrombotic complications and require simultaneous antithrombotic and haemostatic treatments. OBJECTIVE: We propose practical guidance for the diagnosis and management of COVID-19 coagulopathy in persons with haemophilia. RESULTS: Continuation of regular haemostatic treatment is recommended for ambulatory patients. For patients requiring hospital admission and on replacement therapy with factors VIII or IX concentrates, prophylaxis with concentrates should be intensified according to the risk of bleeding complications and associated with prophylactic doses of LMWH. For patients on nonreplacement therapy, emicizumab should be continued and possibly combined with factor VIII and prophylactic doses of LMWH depending on the risk of bleeding and thrombosis. Dose escalation of LMWH tailored to the risk of thrombosis can be employed but not supported by evidence. CONCLUSIONS: These practical recommendations are based on the current literature on COVID-19 with its impact on haemostasis, indications and modalities for thromboprophylaxis mainly in nonhaemophilic patients and how that is likely to affect persons with haemophilia in different circumstances. They will need to be tailored to each patient's clinical status and validated in future studies.

The effect of emicizumab prophylaxis on long-term, self-reported physical health in persons with haemophilia A without factor VIII inhibitors in the HAVEN 3 and HAVEN 4 studies.

INTRODUCTION: Severe haemophilia A (HA) has a major impact on health-related quality of life (HRQoL). AIM: Assess the impact of emicizumab on HRQoL in persons with severe HA (PwHA) without factor VIII (FVIII) inhibitors in the phase 3 HAVEN 3 and 4 studies. METHODS: This pooled analysis examines the HRQoL of PwHA aged ≥ 18 years treated with emicizumab prophylaxis via Haemophilia-Specific Quality of Life Questionnaire for Adults (Haem-A-QoL) and EuroQoL 5-Dimensions 5-levels (EQ-5D-5L). In particular, changes from baseline in Haem-A-QoL 'Physical Health' (PH) domain and 'Total Score' (TS) are evaluated. RESULTS: Among 176 evaluable participants, 96 (55%) had received prior episodic treatment and 80 (45%) prophylaxis; 70% had ≥ 1 target joint and 51% had experienced ≥ 9 bleeds in the previous 24 weeks. Mean Haem-A-QoL PH and TS improved after emicizumab initiation. Mean (standard deviation) -12.0 (21.26)- and -8.6 (12.57)-point improvements were observed in PH and TS from baseline to Week 73; Week 73 scores were 27.9 (24.54) and 22.0 (14.38), respectively. Fifty-four percent of participants reported a clinically meaningful improvement in PH scores (≥ 10 points) by Week 73. Subgroups with poorer HRQoL prior to starting emicizumab (i.e. receiving episodic treatment, ≥ 9 bleeds, target joints) had the greatest improvements in PH scores, and corresponding reductions in missed workdays; change was not detected among those previously taking prophylaxis. No change over time was detected by the EQ-5D-5L questionnaire. CONCLUSIONS: Emicizumab prophylaxis in PwHA without FVIII inhibitors resulted in persistent and meaningful improvements in Haem-A-QoL PH and less work disruption than previous treatment.

Novel therapeutics for hemophilia and other bleeding disorders.

Hemophilia and von Willebrand disease are the most common congenital bleeding disorders. Treatment of these disorders has focused on replacement of the missing coagulation factor to prevent or treat bleeding. New technologies and insights into hemostasis have driven the development of many promising new therapies for hemophilia and von Willebrand disease. Emerging bypass agents including zymogen-like factor IXa and Xa molecules are in development and a bispecific antibody, emicizumab, demonstrated efficacy in a phase 3 trial in people with hemophilia A and inhibitors. Tissue factor pathway inhibitor, the protein C/S system, and antithrombin are targets of novel compounds in development to alter the hemostatic balance and new approaches using modified factor VIII molecules are being tested for prevention and eradication of inhibitor antibodies in hemophilia A. The first recombinant von Willebrand factor (VWF) product has been approved and has unique VWF multimer content and does not contain factor VIII. These new approaches may offer better routes of administration, improved dosing regimens, and better efficacy for prevention and treatment of bleeding in congenital bleeding disorders.

Biological mechanisms underlying inter-individual variation in factor VIII clearance in haemophilia.

Previous studies have highlighted marked inter-individual variations in factor VIII (FVIII) clearance between patients with haemophilia (PWH). The half-life of infused FVIII has been reported to vary from as little as 5.3 hours in some adult PWH, up to as long as 28.8 hours in other individuals. These differences in clearance kinetics have been consistently observed using a number of different plasma-derived and recombinant FVIII products. Furthermore, recent studies have demonstrated that half-life for extended half-life (EHL-) FVIII products also demonstrates significant inter-patient variation. Since time spent with FVIII trough levels <1% has been shown to be associated with increased bleeding risk in PWH on prophylaxis therapy, this variability in FVIII clearance clearly has major clinical significance. Recent studies have provided significant novel insights into the cellular basis underlying FVIII clearance pathways. In addition, accumulating data have shown that endogenous plasma VWF levels, ABO blood group and age, all play important roles in regulating FVIII half-life in PWH. Indeed, multiple regression analysis suggests that together these factors account for approximately 34% of the total inter-individual variation in FVIII clearance observed between subjects with severe haemophilia A. In this review, we consider these and other putative modulators of FVIII half-life, and discuss the biological mechanisms through which these factors impact upon FVIII clearance in vivo.

HIF1-alpha Regulates Acinar Cell Function and Response to Injury in Mouse Pancreas.

We investigated whether intrapancreatic coagulation, with deposition of the fibrinogen-γ dimer (Fib-γD) and hypoxia, affect the severity of acute pancreatitis (AP) in mice. Pancreata of mice with AP induced by administration of cerulein or by L-arginine, or from patients with pancreatitis, had increased deposition of Fib-γD compared with control pancreata. Heparin administration protected mice from cerulein-induced AP and prevented Fib-γD formation. Cerulein administration resulted in activation and stabilization of hypoxia-inducible factor-1α (HIF1α) in pancreata of oxygen-dependent degradation domain-luciferase HIF1α reporter mice. Cerulein also led to induction of genes regulated by HIF1α, including Vegfa and Ero1a, before evidence of Fib-γD deposition or histologic features of AP. Expression of tissue factor, which is regulated by vascular endothelial growth factor, also increased following cerulein administration. Mice with acinar cell-specific disruption of Hif1a (Hif1aAc-/-) developed spontaneous endoplasmic reticulum stress and less severe AP, but did not accumulate Fib-γD following administration of cerulein. Feeding mice increased pancreatic expression of HIF1α, indicating a physiologic role in the exocrine pancreas. Therefore, HIF1α has bifunctional roles, in exocrine pancreas homeostasis and progression of AP that is promoted by intrapancreatic coagulation.