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.

Factor Replacement Treatment for Hemophilia A: Achievements and Perspectives.

The mainstay of treatment for persons with hemophilia A (PwHA) with severe bleeding phenotype is prophylaxis. The pharmacokinetic (PK) profile of native factor VIII (FVIII) imposes the need for rather frequent intravenous injections to ensure effective prophylaxis, but this represents a relevant treatment burden and is associated with suboptimal adherence to treatment. In this light, the advent of extended half-life (EHL) FVIII molecules has improved prophylaxis feasibility and outcomes by favoring treatment individualization and tailoring protection according to specific clinical and nonclinical needs. Different technologies have been used to enhance FVIII PK properties including Fc-fusion and conjugation with polyethylene glycol. Data from clinical development programs for such molecules, together with growing real-world experience, have shown numerous benefits related to the use of EHL FVIII in PwHA. Recently a new class of ultra-long-acting EHL FVIII has been developed to further improve protection against bleeding episodes and achieve the ambitious goal of providing PwHA with hemostatic protection in the nonhemophilia range over longer time periods, hence ensuring very low bleeding rates and improving joint health and quality of life. In this review, the achievements and perspectives of replacement therapies for PwHA are summarized and discussed.

Benefits and risks of non-factor therapies: Redefining haemophilia treatment goals in the era of new technologies.

INTRODUCTION: Over the last decades progress in haemophilia treatment has been remarkable and prophylaxis with clotting factor concentrates in haemophilia A and B has been established as the standard of care in individuals with haemophilia and a severe bleeding phenotype. Besides clotting factor products with prolonged half-life non-factor therapies were developed which enable prophylaxis via subcutaneous administration. Factor VIIIa mimetics like emicizumab facilitate the coagulation pathway and are used in routine clinical practice for indivdiduals with haemophilia A. Rebalancing therapeutic agents like fitusiran, concizumab, marstacimab and serpin PC block the anticoagulant pathway and clinical trials using these products in individuals with haemophilia A and B are ongoing. AIM AND METHODS: A narrative review to asess the benefits and risks of non-factor therapies taking in to account re-defined haemophilia treatment goals. RESULTS: Prophylaxis for prevention of bleeds using non-factor products by subcutaneous administration is effective and results in reductions of bleeding episodes in individuals with haemophilia A or B with and without inhibitors. The treatment with emicizumab showed tolerable safety both in clinical trials and long-term real-world observations with few thrombotic events. In some clinical trials with rebalancing therapies (fitusiran and concizumab) thrombotic events occurred. Monitoring of the haemostatic function of novel therapies especially with concomitant haemostatic treatment is not yet established. CONCLUSION: With the advent of novel therapeutic agents including factor concentrates with ultra-long half-life and improved FVIIIa mimetics aimed at raising the bar of protection into the non-hemophilic range redefinition of haemophilia treatment goals is eagerly needed.

The haemophilia joint health score for the assessment of joint health in patients with haemophilia.

INTRODUCTION: The haemophilia joint health score (HJHS) is a tool used to assess joint changes in patients with haemophilia. There is lack of consensus on the interpretation of HJHS scores and their clinical relevance. AIM: To evaluate available literature reporting HJHS changes over time and assess a possible cut-off value for clinically relevant outcomes and the ideal follow-up for a meaningful score change. METHODS: We conducted a literature search of studies published between 2011 and 2023 where the HJHS version 2.1 had been adopted to detect changes in joint health in patients with haemophilia. We focused on studies that assessed clinical relevance of HJHS changes, evaluated the use of cut-off values and reported a follow-up over time. RESULTS: Our search identified 213 publications of which 53 (25%) were deemed relevant for this review. Of these, 33 (62%) publications reported the total HJHS score and 20 (38%) reported a single joint HJHS score, while the way of reporting HJHS scores/change was highly variable. Ten publications (19%) assessed clinical relevance, but their methods of calculation differed (defining a cut-off score, measuring standardised response mean or minimal detectable change). The follow-up duration varied from 2 weeks to 8 years in these 10 studies. CONCLUSIONS: High variability in assessing HJHS change over time is the primary consequence of its low sensitivity, and the lack of consensus on interpretation and clinical relevance of the score. Therefore, more sensitive tools should be used alongside HJHS to better define the joint health status of patients with haemophilia.

Pathogenesis of osteoarthritis, rheumatoid arthritis, and hemophilic arthropathy: The role of angiogenesis.

INTRODUCTION: The term 'chronic inflammatory arthritis' (IA) can be used to define a group of heterogeneous diseases in which inflammation of the synovium is the common feature while having different pathogenesis and clinical outcomes. This condition can be found in osteoarthritis (OA), rheumatoid arthritis (RA), and hemophilic arthropathy (HA). AIM: The objective is to try to highlight similarities and differences in the three pathological conditions and understand both molecular and physiological mechanisms. METHOD: We have carried out a systematic review of the available literature following the guidelines Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA). RESULTS: By comparing the data in the literature on OA, RA, and HA we have shown that the three pathologies differ in initial etiology but they motivate the same molecular pathways. CONCLUSION: In this review we highlighted the similarities and differences between these diseases, creating ideas for future studies both in vivo and in vitro to develop new therapeutic agents and suggest possible biomarkers to follow the evolution and severity of the disease.

A post hoc analysis of PROTECT VIII kids assessing long-term efficacy and safety of damoctocog alfa pegol in adolescents with severe haemophilia A.

INTRODUCTION: The safety and efficacy of the extended half-life factor VIII (FVIII) product damoctocog alfa pegol (BAY 94-9027, Jivi®) has been demonstrated in the PROTECT VIII Kids study (NCT01775618), where male previously-treated patients (PTPs) aged <12 years old with severe haemophilia A and ≥ 50 exposure days (EDs) were treated prophylactically. The PROTECT VIII Kids extension study assessed the long-term safety and efficacy of damoctocog alfa pegol in the same population. AIM: To evaluate the long-term impact of damoctocog alfa pegol in a post hoc subgroup analysis of adolescent patients in the PROTECT VIII Kids study and its extension from 12th birthday onwards. METHODS: The current analysis included PTPs aged ≥12 years old, who remained in the extension for ≥6 months following their 12th birthday. The observation period was defined as the time from 12th birthday to the end of the extension period; all data from this birthday were included whether in the main study or extension phase. The main efficacy variable was annualised bleeding rate (ABR) and the main safety variable was the frequency of inhibitor development. RESULTS: This subgroup analysis comprised 25 patients. Median observation time after 12th birthday was 3.2 years. Median total/joint/spontaneous ABRs in the observation period were 1.7/0.7/0.3, respectively. Safety findings were consistent with those reported for the overall study population; no confirmed FVIII inhibitors or anti-drug antibodies were reported. CONCLUSIONS: Damoctocog alfa pegol is efficacious with a favourable safety profile in adolescents with haemophilia A, supporting its long-term use in children and adolescents.

Long-Term Efficacy and Safety of Damoctocog Alfa Pegol Prophylaxis in Patients with Haemophilia A Aged 12-<18 Years at Enrolment into PROTECT VIII.

INTRODUCTION: The phase 2/3 PROTECT VIII study demonstrated long-term efficacy and safety of damoctocog alfa pegol (BAY 94-9027; Jivi®), a B-domain-deleted recombinant factor VIII (FVIII), site-specifically PEGylated to improve its pharmacokinetic profile. We report a post hoc assessment of bleeding and safety outcomes in the subgroup of patients, aged 12-<18 years at enrolment. METHOD: PROTECT VIII was a multicentre, open-label study of previously treated males aged 12-65 years with severe haemophilia A (FVIII <1%). Twelve patients were included in this analysis. All received damoctocog alfa pegol prophylaxis for the total time in study (median [range] time in study 4.0 [1.3-6.2] years). RESULTS: Overall median (Q1; Q3) total and joint annualised bleeding rates were 1.8 (0.4; 5.1) and 0.7 (0.2; 1.8), respectively, for the entire study. During the last 6 months of treatment, eight (66.7%) and ten (83.3%) out of 12 patients experienced zero total and joint bleeds, respectively. No patient developed FVIII inhibitors. No deaths or thrombotic events were reported. CONCLUSION: Efficacy and safety of damoctocog alfa pegol were confirmed in adolescent patients with haemophilia A, with data for up to 6 years supporting its use as a long-term treatment option in this group as they transition into adulthood.

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.

Synovitis and joint health in patients with haemophilia: Statements from a European e-Delphi consensus study.

INTRODUCTION: Synovitis, a common feature in haemophilia, is triggered by the presence of blood in joints, and represents the first step towards the development of chronic arthropathy. Synovitis may be detected early by means of ultrasound or magnetic resonance imaging scan; clinical joint scores are less sensitive in this setting. Regular long-term prophylaxis with clotting factor concentrates, as primary prophylaxis and tailored to individual needs, has high efficacy in preventing synovitis. In general, higher factor levels lower bleeding risk, but no direct correlation between factor levels and synovitis incidence has been demonstrated. AIM: This study aimed to develop an expert consensus relating to the definition, pathophysiology, diagnosis, prevention, follow-up and treatment of synovitis, recognising its relevance for joint health and taking into account existing knowledge gaps. METHODS: A Delphi consensus study was designed and performed. An expert group prepared 22 statements based on existing literature; a wider expert panel subsequently voted on these. RESULTS: Retention of panellists was high. Four statements required amending and consensus on all statements was achieved after three rounds of voting. CONCLUSION: This e-Delphi consensus study addressed the importance of synovitis in joint health of people with haemophilia and highlighted knowledge gaps in this field. Studies on the natural course of synovitis are lacking and the biological mechanisms underlying this process are not yet fully elucidated. While basic and clinical research proceeds in this field, expert consensus can help guide clinicians in their routine clinical practice, and Delphi methodology is often used to produce best-practice guidelines.

Prophylaxis use of clotting factor replacement products in people with non-severe haemophilia: A review of the literature.

INTRODUCTION: People with non-severe haemophilia appear to be under-treated in many countries, and this may lead to joint damage and worsen quality of life. AIM: To review literature for clotting factor replacement prophylaxis in people with non-severe haemophilia A and B (HA/HB) in relation to long-term outcomes to support clinical decision-making. METHODS: A targeted literature search was performed to identify studies published between 2000 and 2021 that included prophylaxis in people with non-severe HA/HB and long-term outcomes, including annualized bleeding rates, joint health and quality of life. RESULTS: Although eligible articles included 2737 and 2272 people with mild or moderate HA, respectively, only 22% (n = 609) and 29% (n = 668) reported treatment regimens. A total of 549 people with moderate HA were treated with factor replacement prophylaxis and were from high-income countries. On the contrary, nearly all people with mild HA received desmopressin (n = 599). Details of treatment regimens for women with haemophilia and people with HB were sparse. Three studies provided long-term outcomes for people with moderate haemophilia who received prophylaxis with factor concentrate, supporting early prophylaxis in people with a frequent bleeding phenotype regardless of their endogenous clotting factor level to preserve joint health. CONCLUSION: There remain large knowledge gaps when considering how to provide optimal treatment for people with non-severe haemophilia. Nonetheless, there is a strong rationale that prophylaxis should be considered early in life according to similar strategies as for severe haemophilia for those with a frequent severe bleeding phenotype.

Emicizumab dose up-titration in case of suboptimal bleeding control in people with haemophilia A.

INTRODUCTION: Emicizumab promotes effective haemostasis in people with haemophilia A (PwHA). It is indicated for routine prophylaxis of bleeding episodes in PwHA with or without factor (F)VIII inhibitors. AIM: To investigate the effect of emicizumab dose up-titration in PwHA with suboptimal bleeding control. METHODS: Data from seven completed or ongoing phase III studies were pooled. Pharmacokinetics, pharmacodynamics and bleeding events were evaluated before and after dose up-titration. Adverse events (AEs) were compared between PwHA with and without dose up-titration. RESULTS: Of 675 PwHA evaluable for the analysis, 24 (3.6%) had their maintenance dose up-titrated to 3 mg/kg once weekly (QW). Two participants had neutralising antibodies (nAbs) associated with decreased emicizumab exposure, and dose increase did not compensate for the effect of nAbs. In the other 22 participants, mean emicizumab steady-state trough concentrations increased from 44.0 to 86.2 µg/mL after up-titration. The median (interquartile range [IQR]) efficacy period prior to up-titration was 24.6 (24.0-32.0) weeks. The model-based annualised bleed rate for 'treated bleeds' and 'all bleeds' decreased by 70.2% and 72.9%, respectively, after a median (IQR) follow-up of 97.1 (48.4-123.3) weeks in the up-titration period. Incidences of injection-site reactions and serious AEs were higher in PwHA with up-titration; however, this was already observed in these participants before the dose up-titration. Overall, the safety profile appeared similar between PwHA with and without up-titration. CONCLUSION: The dose up-titration to 3 mg/kg QW was well tolerated. Bleed control improved in most participants whose bleeding tendency was inadequately controlled during clinical trials.

Laying the foundations for gene therapy in Italy for patients with haemophilia A: A Delphi consensus study.

INTRODUCTION: Current treatment for haemophilia A involves factor VIII replacement or non-replacement (emicizumab) therapies, neither of which permanently normalise factor VIII levels. Gene therapy using adeno-associated viral (AAV) vectors is an emerging long-term treatment strategy for people with severe haemophilia A (PwSHA) that is likely to be available for clinical use in the near future. AIM: This article proposes practical guidelines for the assessment, treatment, and follow-up of potential PwSHA candidates for AAV-based gene therapy. METHOD: Using the Delphi method, a working group of Italian stakeholders with expertise in and knowledge of the care of adults with haemophilia A analysed literature for AAV-based gene therapy and drafted a list of statements that were circulated to a panel of Italian peers. During two rounds of voting, panel members voted on their agreement with each statement to reach a consensus. RESULTS: The Delphi process yielded 40 statements regarding haemophilia A gene therapy, across five topics: (1) organisational model; (2) multidisciplinary team; (3) patient engagement; (4) laboratory surveillance; and (5) patient follow-up and gene therapy outcomes. The consensus was reached for all 40 statements, with the second round of voting needed for five statements. CONCLUSION: Use of the hub-and-spoke organisational model and multidisciplinary teams are expected to optimise patient selection for gene therapy, as well as the management of dosing and patient follow-up, patient engagement, laboratory surveillance, and patient expectations regarding outcomes. This approach should allow the benefits of AAV-based gene therapy for haemophilia A to be maximised.

Applicability of the European Society of Cardiology Guidelines on the management of acute coronary syndromes to older people with haemophilia A - A modified Delphi consensus by the ADVANCE Working Group.

INTRODUCTION: As people with haemophilia (PWH) receive better treatment and live longer they are more likely to encounter cardiovascular disease (CVD) and other comorbidities. ESC guidelines for the acute management of patients presenting with acute coronary syndrome (ACS) are based on the non-haemophilia population. AIM: To review the guidelines and propose relevant adaptations for PWHA without inhibitors who are treated with prophylaxis and present with ACS. METHODS: As part of the ADVANCE Group, 20 European haemophilia experts used a modified Delphi approach to develop and gain consensus on proposed adaptations of the ESC guidelines for PWHA without inhibitors. RESULTS: Of the 32 Class I recommendations across both guidelines, adaptions were considered necessary and proposed for 15. The adaptions highlight the need to provide sufficient FVIII trough levels at the time of antithrombotic treatment in people with haemophilia A (HA) without inhibitors. Patients receiving emicizumab prophylaxis and requiring oral anticoagulation therapy or combined single antiplatelet plus oral anticoagulation therapy will require additional FVIII replacement therapy. CONCLUSION: In the absence of high-quality clinical evidence, the combined expert opinion used to develop these adaptions to the current ESC guidelines may help to guide clinicians in their treatment decisions when a PWHA presents with ACS.

Simoctocog alfa (Nuwiq®) in previously untreated patients with severe haemophilia A-Final efficacy and safety results from the NuProtect study.

INTRODUCTION: Simoctocog alfa (Nuwiq®) is a 4th generation recombinant FVIII with proven efficacy for the prevention and treatment of bleeding episodes (BEs) in previously treated patients with severe haemophilia A. The NuProtect study assessed the immunogenicity, efficacy and safety of simoctocog alfa in 108 previously untreated patients (PUPs). The incidence of high-titre inhibitors was 16.2% and no patients with non-null F8 mutations developed inhibitors. AIM: To report the efficacy and safety results from the NuProtect study. METHODS: PUPs received simoctocog alfa for prophylaxis, treatment of BEs, or as surgical prophylaxis. The efficacy of prophylaxis (during inhibitor-free periods) was assessed using annualised bleeding rates (ABRs). The efficacy in treating BEs and in surgical prophylaxis was assessed using a 4-point scale. Adverse events were recorded throughout the study. RESULTS: Of 108 PUPs treated with simoctocog alfa, 103 received at least one prophylactic dose and 50 received continuous prophylaxis for at least 24 weeks. In patients on continuous prophylaxis, the median ABR was 0 (mean 0.5) for spontaneous BEs and 2.5 (mean 3.6) for all BEs. In 85 patients who had BEs, efficacy of BE treatment was excellent or good for 92.9% (747/804) of rated BEs; 92.3% of BEs were treated with 1 or 2 infusions. The efficacy of surgical prophylaxis was excellent or good for 94.7% (18/19) of rated procedures. There were no safety concerns and no thromboembolic events. CONCLUSION: Simoctocog alfa was efficacious and well tolerated as prophylaxis, surgical prophylaxis and for the treatment of BEs in PUPs with severe haemophilia A.

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.

Managing invasive procedures in haemophilia patients with limited resources, extended half-life concentrates or non-replacement therapies in 2022.

New treatment possibilities and modalities are now available globally for patients with haemophilia requiring surgery or invasive procedures. The first is the appropriate application of low-dose protocols of clotting factor concentrates (CFC) achieving adequate perioperative haemostasis in resources constraint environments. The increasing availability of CFC through humanitarian aid programs allows more invasive surgeries to be performed for which efficacy and safety data should be more widely collected and reported. Second, extended half-life CFC that are increasingly available in many countries represent valuable alternatives to standard half-life products in surgical patients allowing reduced number of infusions and lower consumption, in particular for extended half-life factor IX. Third, in the era of recently introduced nonfactor prophylaxis, some minor surgical procedures can now be performed without additional haemostatic treatment, others with few low-dose administrations of CFC or bypassing agents. Additional factor VIII/IX or recombinant activated factor VII has proven to be safe and effective in association with emicizumab for major surgeries and it was effectively given at low doses in association with fitusiran (including activated prothrombin complex concentrate). No thrombotic complications have been reported in the surgical setting so far. A multidisciplinary team/facility remains crucial to manage major surgery in patients on prophylaxis with these new agents.

Befovacimab, an anti-tissue factor pathway inhibitor antibody: Early termination of the multiple-dose, dose-escalating Phase 2 study due to thrombosis.

INTRODUCTION: Befovacimab (formerly BAY 1093884) is a fully human monoclonal antibody able to bind to tissue factor pathway inhibitor (TFPI) and developed as a non-replacement therapy for individuals with haemophilia A/B, with or without inhibitors. AIM: To assess the safety of multiple escalating doses of befovacimab in individuals with severe haemophilia A/B with or without inhibitors. METHODS: In this non-randomised, open-label Phase 2 study (NCT03597022), adult males with <1% factor VIII or <2% factor IX and ≥4 bleeds in the previous six months were enrolled in three dose cohorts (100/225/400 mg). Participants received befovacimab subcutaneously once weekly. The primary endpoint was safety; secondary endpoints included annualised bleeding rate (ABR) and pharmacokinetics/pharmacodynamics (PK/PD) of befovacimab. RESULTS: A total of 24 participants (n = 8 in each dose cohort) were treated for 2-47 weeks. Patients treated with 100 mg and 225 mg doses of befovacimab demonstrated improved bleeding control compared with pre-study bleeding rates, with a dose-dependent effect. Dosing was suspended and the study prematurely terminated following three drug-related thrombotic serious adverse events (SAEs): two at the 225 mg dose and one at the 400 mg dose. These occurred in the absence of bleeding episodes or concomitant use of replacement/bypass therapies. No laboratory abnormalities were observed, and PK/PD data did not show correlation between SAE occurrence and levels of circulating befovacimab or free TFPI. CONCLUSION: Despite favourable initial results from preclinical and clinical studies, a positive safety profile of befovacimab was not confirmed. The lack of SAE-related laboratory abnormalities or differentiating PK/PD characteristics in participants experiencing SAEs raises concerns about the predictability of thrombosis following befovacimab treatment and emphasises the need for further investigation into the therapeutic window of anti-TFPI treatment.

Predictors of inhibitor eradication by primary immune tolerance induction in severe haemophilia A with high responding inhibitors.

BACKGROUND: Immune tolerance induction (ITI) is the only proven strategy to eradicate factor VIII inhibitors in patients with haemophilia A (HA). AIM: To identify patients and treatment options with the highest chance of inhibitor eradication by primary ITI. PATIENTS AND METHODS: In the frame of the Italian ITI Registry, carried out from 1995 to 2015 (last follow-up 2018), 137 primary ITI courses in severe HA patients (90/137 with poor prognosis) were analysed for predictors of outcome (complete/partial response or failure). Sixty-six of them (48%) were prospectively evaluated. RESULTS: ITI was successful in 91/137 patients (66.4%) and 70 (51.1%) achieved complete response within 11 months (median). Historical peak titres ≤200 BU/ml (P = .033), inhibitor titres ≤5 BU/ml at ITI start (P = .001), peak titres ≤100 BU/ml during ITI (P < .001) and missense mutations and small insertions/deletions of FVIII gene (P = .027) predicted complete inhibitor eradication. A score that considers the cumulative number of these variables predicted complete response with positive predictive values up to .81 at ITI start and .91 during ITI, respectively. Patients who had no bleeding (OR, 3.45, 95% CI: 1.4-8.6) nor other adverse events (OR 2.6, 95%CI: 1.3-5.3) during ITI had higher chances of complete response. During the 120-month follow-up (median), 2/70 patients who had achieved complete response relapsed (2.9%). CONCLUSIONS: This Registry, with a centralized review of outcomes, homogeneous data collection (half of which prospective) and long-term follow-up, provides insights for optimizing ITI, with a rationale for further studies in the currently evolving scenario of inhibitor management in HA patients.

A multicenter, open-label phase 3 study of emicizumab prophylaxis in children with hemophilia A with inhibitors.

Emicizumab, a bispecific humanized monoclonal antibody, bridges activated factor IX (FIX) and FX to restore the function of missing activated FVIII in hemophilia A. Emicizumab prophylaxis in children with hemophilia A and FVIII inhibitors was investigated in a phase 3 trial (HAVEN 2). Participants, previously receiving episodic/prophylactic bypassing agents (BPAs), were treated with subcutaneous emicizumab: 1.5 mg/kg weekly (group A), 3 mg/kg every 2 weeks (group B), or 6 mg/kg every 4 weeks (group C). Pharmacokinetics, safety, and efficacy (including an intraindividual comparison of participants from a noninterventional study) were evaluated. Eighty-five participants aged <12 years were enrolled. In group A (n = 65), the annualized rate of treated bleeding events (ABRs) was 0.3 (95% confidence interval [CI], 0.17-0.50), and 77% had no treated bleeding events. Intraindividual comparison of 15 participants who previously took BPA prophylaxis showed that emicizumab prophylaxis reduced the ABR by 99% (95% CI, 97.4-99.4). In groups B (n = 10) and C (n = 10), ABRs were 0.2 (95% CI, 0.03-1.72) and 2.2 (95% CI, 0.69-6.81), respectively. The most frequent adverse events were nasopharyngitis and injection-site reactions; no thrombotic events occurred. Two of 88 participants developed antidrug antibodies (ADAs) with neutralizing potential, that is, associated with decreased emicizumab plasma concentrations: 1 experienced loss of efficacy, and, in the other, ADAs disappeared over time without intervention or breakthrough bleeding. All other participants achieved effective emicizumab plasma concentrations, regardless of the treatment regimen. Emicizumab prophylaxis has been shown to be a highly effective novel medication for children with hemophilia A and inhibitors. This trial was registered at www.clinicaltrials.gov as #NCT02795767.

Prophylaxis in children with haemophilia in an evolving treatment landscape.

INTRODUCTION: For children with haemophilia, early initiation of prophylaxis is crucial to prevent life-threatening bleeds and maintain joint health throughout life. Options for prophylaxis have recently increased from replacement therapy with standard or extended half-life coagulation factor products to include other haemostasis products, such as the non-replacement therapy emicizumab. AIM: To review key factors that determine the choice of prophylaxis in young children. METHODS: Key clinical questions on the implementation of prophylaxis for haemophilia in children were identified and PubMed was searched for evidence supporting guidance on the implementation of prophylaxis. RESULTS: The results of the literature search and the practical experience of the authors were used to build consensus on when to start prophylaxis, the pros and cons of the products available to guide the choice of product, and practical aspects of starting prophylaxis to guide the choice of regimen. CONCLUSIONS: In this era of increasing therapeutic choices, available information about the range of treatment options must be considered when initiating prophylaxis in young children. Parents or care givers must be sufficiently informed to allow informed shared decision making. Although plentiful data and clinical experience have been gathered on prophylaxis with clotting factor replacement therapy, its use in young children brings practical challenges, such as the need for intravenous administration. In contrast, our relatively brief experience and limited data with subcutaneously administered non-replacement therapy (i.e., emicizumab) in this patient group imply that starting emicizumab prophylaxis in young children requires careful consideration, despite the more convenient route of administration.