Budget impact of prophylactic treatment of rVIII-SingleChain in moderate and severe hemophilia A in Italy.

INTRODUCTION: rVIII-SingleChain, a recombinant factor VIII (rFVIII), has demonstrated safety and efficacy in patients with hemophilia A in clinical trials and real-world evidence. This analysis aimed to estimate the potential budget impact of increasing the usage of rVIII-SingleChain for the prophylactic treatment of hemophilia A over 3 years in Italy. METHODS: Patients with moderate and severe hemophilia A receiving prophylaxis were included in the analysis. Epidemiological data were obtained from published literature. Mean product consumption and mean annual bleeding rate for rVIII-SingleChain, rFVIIIFc, octocog alfa and BAY 81-8973 were based on pooled real-world data from Italy, Germany and US. A budget impact model has been developed in order to compare two scenarios: a base-case scenario where current rVIII-SingleChain shares are kept constant over 3 years and an alternative scenario where rVIII-SingleChain shares increase by taking from other rFVIII products. Analysis 1 was based on the current Italian list prices and Analysis 2 considered current regional acquisition prices for both scenarios. RESULTS: Annually, adult patients treated with rVIII-SingleChain prophylaxis are expected to consume 324,589 units per patient, resulting in annual costs of €240,196 per patient. In Analysis 1, comparing the base case (constant market share of 9% rVIII-SingleChain over time) with the alternative scenario (higher rVIII-SingleChain market share and increasing from 15% in the first year to 25% in the third year), the total expenditure for prophylaxis using rFVIII products is expected to decrease by €1.4 million in Year 1, by €3.1 million in Year 2 and by €5.4 million in Year 3. In Analysis 2 based on regional prices, the results remained consistent. DISCUSSION/CONCLUSION: This analysis suggests that increasing utilization of rVIII-SingleChain in hemophilia A patients may lead to cost savings as a result of reduced consumption with uncompromised efficacy in bleed protection.

Why was the study done? Hemophilia A is a rare inherited bleeding disorder. People with severe hemophilia are more likely to bleed compared to people without hemophilia and bleeds can occur spontaneously or in response to trauma. Patients are treated with medication to reduce the chance of bleeding. However, the cost of treating patients with hemophilia can be high and place demands on the healthcare system.What did we do and find?This study looked at the cost of treating people with hemophilia in Italy and used a type of economic analysis (called budget impact modelling) to estimate the effect of increasing the use of a particular medication (rVIII-SingleChain), compared to other medications that are available. Different variations of the model were tested to compare a range of scenarios.The results of this analysis suggested that increasing the use of rVIII-SingleChain may lead to cost-savings for the Italian healthcare system, compared to using the other currently available treatments. This analysis suggests that the use of rVIII-SingleChain enables people with hemophilia A to remain protected from bleeds, whilst using less product compared to other available medications.What is the influence of this study on the wider field?This type of analysis can be useful to healthcare systems, to guide the decision-making process regarding which medications to use or when making decisions related to healthcare policy.

Eradication of FIX inhibitor in haemophilia B children using low-dose immune tolerance induction with rituximab-based immunosuppressive agent(s) in China.

INTRODUCTION: Development of haemophilia B inhibitors (HBI) results in the ineffectiveness of FIX replacement therapy. Inhibitor eradication by immune tolerance induction (ITI) is therefore necessary. In HBI, ITI even at high FIX dose is less effective and has a higher risk of severe complications. AIM: To characterize clinical features and outcome of ITI on HBI. METHODS: This retrospective study was conducted in Haemophilia Paediatric Comprehensive Care Centre of China. We used low-dose ITI (25-50 FIX IU/kg/three-times-weekly to every-other-day) with domestic prothrombin complex concentrate (PCC), combined with two successive immunosuppressive (IS) regimens. RESULTS: Sixteen HBI children, representing 5.7% of all and 14.4% of our severe registered HB patients, were enroled. Seven cases reported allergic reactions (ARs) proximal to inhibitor development. The historic peak inhibitor titre was median 54.2 (range 4.7-512) BU, and 15 (93.8%) had high-titre inhibitors. Twelve patients adherent to ITI were analysable. Of the nine ITI patients who received rituximab/prednisone (IS Regimen-1), four achieved tolerization in 1.4-43.3 months. Two subsequently relapsed but re-tolerized after a second course of IS Regimen-1. During ITI, the median treated bleed was .39/month (82.7% reduction from before ITI), and the incidence of AR and nephrotic syndrome (NS) complications was each at 22% (2/9). Three ITI patients received modified 'Beutel' protocol (IS Regimen-2) using multiple-IS-drugs, and two had rapid tolerization (.8 and 1.8 months). CONCLUSIONS: Inhibitor eradication could be achieved by low-dose ITI protocol using PCC combined with IS. Larger studies are needed to confirm if ITI with IS Regimen-2 is more effective with less complications.

Confirmed long-term safety and efficacy of prophylactic treatment with BAY 94-9027 in severe haemophilia A: final results of the PROTECT VIII extension study.

INTRODUCTION: The phase 2/3 PROTECT VIII main study demonstrated efficacy and safety of BAY 94-9027 (damoctocog alfa pegol; Jivi® ), a B-domain-deleted recombinant factor VIII (FVIII), site-specifically PEGylated to extend its half-life. AIM: To report the final efficacy and safety data for BAY 94-9027 from the PROTECT VIII extension. METHODS: Previously treated males aged 12-65 years with severe haemophilia A (FVIII <1%) who completed the multicentre, open-label PROTECT VIII main study were eligible for the extension. Patients received either on demand or prophylaxis treatments (30-40 IU/kg twice weekly [2 × W], 45-60 IU/kg every 5 days [E5D], or 60 IU/kg every 7 days [E7D]) and could switch to any prophylaxis regimen (variable frequency) as needed. Annualised bleeding rates (ABR), zero bleeds and safety outcomes were included in this final analysis. RESULTS: At extension completion, patients (n = 121) received BAY 94-9027 for a median (range) total time of 3.9 (0.8-7.0) years. Median (Q1; Q3) total ABR was 1.49 (0.36; 4.80) for prophylaxis patients (n = 107), compared with 34.09 (20.3; 36.6) for on-demand patients (n = 14). Median total ABRs for 2 × W (n = 23), E5D (n = 33), E7D (n = 23) and variable frequency (n = 28) groups were 1.57, 1.17, 0.65 and 3.10, respectively. Of prophylaxis patients, 20.6% were bleed-free during the entire extension (median time, 3.2 years) and 50.0% were bleed-free during the last 6 months. No patient developed FVIII inhibitors. No deaths or thrombotic events were reported. CONCLUSIONS: Efficacy and safety of BAY 94-9027 was confirmed, with extension data supporting its use as a long-term treatment option for patients with 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.

Recombinant FVIIIFc Versus BAY 94-9027 for Treatment of Patients with Haemophilia A: Comparative Efficacy Using a Matching Adjusted Indirect Comparison.

INTRODUCTION: Prophylaxis with recombinant factor VIII (rFVIII) is the current standard of care for haemophilia A. Several approaches have been used to extend the half-life of rFVIII to improve prophylaxis outcomes. An indirect comparison of pivotal clinical trial data was performed to evaluate the relative efficacy of two extended half-life therapies approved for the prophylactic treatment of haemophilia A: recombinant FVIII-IgG1 Fc domain fusion protein (rFVIIIFc) and pegylated rFVIII (BAY 94-9027). METHODS: Matching-adjusted indirect comparison (MAIC) was conducted to compare the rFVIIIFc individualised prophylaxis arm of the A-LONG phase III clinical trial (n = 117) and the BAY 94-9027 approved dosing regimens of the PROTECT VIII phase II/III study (n = 110). Following matching for baseline characteristics, mean annualised bleeding rate (ABR) and the proportion of patients with zero bleeds were compared for rFVIIIFc and BAY 94-9027. Additional supportive analyses comparing rFVIIIFc individualised prophylaxis and the individual prophylaxis regimens included in the PROTECT VIII group (twice weekly, and every 5 and 7 days [Q5D and Q7D]) were conducted. RESULTS: Mean ABR was lower in the rFVIIIFc individualised prophylaxis group versus the BAY 94-9027 pooled prophylaxis population (3.0 versus 4.9), providing a clinically relevant and statistically significant difference (mean difference [MD] - 1.9; 95% confidence interval [CI] - 3.5 to - 0.4). A statistically significant difference in ABR was also observed for rFVIIIFc compared with BAY 94-9027 Q7D (3.2 versus 6.4; MD - 3.3; 95% CI - 6.4 to - 0.2). The difference in the proportion of patients with zero bleeds between rFVIIIFc (46.5%) and BAY 94-9027 pooled prophylaxis population (38.2%) was not statistically significant (odds ratio 1.4; 95% CI 0.8 to 2.5). CONCLUSIONS: This indirect treatment comparison indicates a statistically significant and clinically relevant difference in ABR favouring individualised prophylaxis with rFVIIIFc versus BAY 94-9027 prophylaxis. The proportion of patients with zero bleeds was numerically greater with rFVIIIFc treatment but did not achieve statistical significance.

Pathological mechanism of joint destruction in haemophilic arthropathy.

Haemophilic arthropathy (HA), caused by intra-articular haemorrhage, is one of the most common complications in patients with haemophilia. Factor replacement therapy provides missing coagulation factors to prevent children with haemophilia from joint bleeding and decreases their risk for HA. However, haemophilia patients in developing countries are still suffering from HA due to insufficient replacement therapy. Symptoms such as pain and activity limitations caused by HA seriously affect the functional abilities and quality of life of patients with HA, causing a high disability rate in the haemophilia cohort. The pathological mechanism of HA is complicated because the whole pathological mainly involves hypertrophic synovitis, osteopenia, cartilage and bone destruction, and these pathological changes occur in parallel and interact with each other. Inflammation plays an important role in the whole complex pathological process, and iron, cytokines, growth factors and other factors are involved. This review summarizes the pathological mechanism of HA to provide background for clinical and basic research.

Monitoramento do horizonte tecnológico: Medicamentos em desenvolvimento para o tratamento da Hemofilia A / Monitoring the technological horizon: Drugs under development for the treatment of Hemophilia A

A DOENÇA: A hemofilia A (HA) é uma doença genética hemorrágica, com herança ligada ao cromossomo X. Uma vez que os homens apresentam apenas um cromossomo X e não há alelo homólogo correspondente no cromossomo Y, a hemofilia A acomete principalmente indivíduos do sexo masculino. Ela é caracterizada pela deficiência ou anormalidade da atividade coagulante do fator VIII. Os pacientes tendem a ter sangramento recorrente de gravidade variável, que ocorre espontânea ou pós-traumaticamente em qualquer órgão ou tecido. A gravidade dos episódios hemorrágicos varia de acordo com a atividade residual coagulante do fator VIII. A maioria envolve sangramento intra-articular e hemartrose, a qual, quando recorrente e tratada de forma inadequada, resulta em dano permanente à cartilagem articular. No Brasil, em 2019, havia 10.821 pessoas diagnosticadas com HA, sendo 98,5% do sexo masculino e 36,6% tendo seu quadro clínico classificado como grave. A prevalência da HA estimada é de, aproximadamente, um caso em cada 10.000 nascimentos do sexo masculino. Dentre as coagulopatias hereditárias no Brasil, a HA é a mais frequente, correspondendo à 38,7% do total (4). No país, entre 1999 e 2016, ocorreram 927 óbitos masculinos relacionados à hemofilia, sendo 45,1% como causa básica e 54,9% como causa associada ao óbito. A principal causa associada foi hemorragia intracraniana, seguida de doenças infecciosas e parasitárias, prevalecendo a doença pelo vírus da imunodeficiência humana (HIV) e a hepatite viral. TRATAMENTO RECOMENDADO: No Brasil, as recomendações a respeito do tratamento da HA estão dispostas na segunda edição do manual de hemofilia, publicado pelo Ministério da Saúde em 2015. Também estão disponíveis o Protocolo de uso de Profilaxia Primária para Hemofilia Grave e o Protocolo de uso de indução de imunotolerância para pacientes com hemofilia A e inibidor. O tratamento da hemofilia inclui prevenção de sangramento e danos nas articulações e gerenciamento imediato de episódios hemorrágicos. O principal pilar é a reposição do fator de coagulação deficiente ­ no caso da HA, a reposição do fator VIII. A profilaxia com concentrados de fator de coagulação é referida como terapia de reposição regular, enquanto a terapia de reposição episódica ou terapia sob demanda caracteriza-se pela administração do fator apenas no momento de um sangramento. Diferentes terapias de coagulação estão disponíveis para o tratamento da hemofilia. Há os derivados de plasma humano (hemoderivados), os quais são submetidos a técnicas de diagnóstico, inativação viral e purificação; ou concentrados recombinantes, desenvolvidos por técnicas de biologia molecular. Dos recombinantes, há fatores de coagulação com meia-vida estendida, que aumentam a segurança hemostática na profilaxia e mantêm os níveis do fator mais elevados. Em eventos hemorrágicos, outros agentes são também recomendados, como o acetato de desmopressina e os antifribinolíticos (ácido tranexâmico e ácido épsilon-aminocaproico). ESTRATÉGIA DE BUSCA: Para identificar os medicamentos em pesquisa clínica para HA, foi consultado o sítio eletrônico ClinicalTrials.gov, em 07 de maio de 2021, empregando os termos "hemophilia" e "haemophilia". Foram considerados medicamentos que estão em fase 3 de pesquisa clínica, com a HA como alvo e sem registro para essa indicação terapêutica no Brasil. Para a pesquisa de resultados publicados dos ensaios clínicos, utilizaram-se os códigos de registro do ClinicalTrials.gov referentes aos estudos identificados na etapa anterior e os nomes de cada um dos medicamentos. Entre 13 e 20 de maio de 2020, foram feitas buscas nas bases de dados MEDLINE (via Pub Med), EMBASE e, também, o Google Acadêmico. De forma complementar, anais de congressos científicos, diretrizes clínicas internacionais e a base de dados CortellisTM foram consultados. Os estados regulatórios das terapias selecionadas foram consultados nos sítios eletrônicos da Agência Nacional de Vigilância Sanitária (Anvisa), European Medicines Agency (EMA) e Food and Drug Administration (FDA). NOVAS TERAPIAS: terapias alternativas (sem reposição de fator) que inibem as vias anticoagulantes: Concizumabe. Fitusiran. Marstacimabe. Terapia gênica. Giroctocogene fitelparvovec. Fatores de coagulação VIII com meia-vida estendida. LIMITAÇÕES: A maioria dos estudos de fase 3 localizados nesse informe ainda está em andamento. Embora alguns deles já possuam resultados publicados, esses estão disponíveis apenas sob forma de resumo ou apresentações em eventos científicos. As conclusões sobre a eficácia e segurança das tecnologias ainda são prematuras. Pacientes com hemofilia têm qualidade de vida reduzida devido, principalmente, a dor e às limitações físicas, com repercussão potencial na educação, no emprego e nos relacionamentos interpessoais (56). Avanços em técnicas de biologia molecular e terapias gênicas vêm mudando o cenário dos tratamentos disponíveis para a hemofilia. As melhorias nos fatores de coagulação de reposição permitem, por exemplo, a redução da frequência da infusão e a melhora da atividade biológica. O desenvolvimento de terapias de reposição sem fator de coagulação começou recentemente a oferecer uma abordagem alternativa de tratamento para pacientes com hemofilia. A terapia gênica oferece o potencial de uma cura vitalícia, uma melhor qualidade de vida e liberdade de várias morbidades relacionadas, embora com efeitos de longo prazo ainda desconhecidos. Os dois anticorpos monoclonais (concizumabe e marstacimabe) e o iRNA (fitusiran) são terapias de administração subcutânea que inibem as vias anticoagulantes, reduzindo ou cessando a necessidade de reposição do fator de coagulação. Estudos de fase 2 e resultados preliminares de estudos de fase 3 vêm demonstrando uma redução da taxa de sangramento anual de pacientes com HA que fizeram uso dessas tecnologias. Em relação à terapia gênica, o valoctocogene roxaparvovec e o giroctocogene fitelparvovec estão em fase 3 de desenvolvimento, e demonstram resultados promissores. Dados de estudos de fase 3 publicados em resumos e apresentações de congresso mostram níveis de atividade de FVIII substanciais e sustentados, reduções em episódios de sangramento autorrelatados, reduções em infusões de reposição de FVIII e perfil de segurança bem tolerado após a terapia com valoctocogene roxaparvovec. Os fatores de coagulação VIII com meia-vida estendida permitem a conveniência da redução na frequência da infusão do fator. No entanto, em geral, essas reduções são modestas. Foi apresentado o efanesoctocog alfa que possui três a quatro vezes a meia-vida relacionada a outros fatores VIII, permitindo a sua administração uma vez por semana. Os dados publicados abordam, em geral, a farmacocinética do medicamento, não permitindo conclusões sobre a sua eficácia e segurança. As tecnologias abordadas nesse informe de MHT estão em estudos de fase 3. Em geral, os resultados publicados são dos estudos de fase 2 ou são resultados preliminares de estudos de fase 3, publicados como resumos de eventos científicos. Em relação aos registros sanitários em outros países, das terapias avaliadas, apenas o Valoctocogene roxaparvovec tem a autorização de comercialização solicitada no EMA. No FDA, a autorização foi solicitada, mas a agência pediu dados suplementares e a empresa ainda não submeteu o pedido novamente (58). Nenhuma outra terapia discutida nesse MHT está registrada no EMA ou no FDA até a data de consulta. O desenvolvimento de novos tratamentos para a HA vem permitindo o maior controle da doença e de seus impactos. Caso tenham o registro aprovado por agências regulatórias e solicitada a incorporação destas tecnologias, análises cuidadosas devem ser feitas quanto ao perfil de eficácia/efetividade comparativa e segurança, além do impacto econômico que poderiam gerar ao sistema de saúde.

Tailoring haemophilia A prophylaxis with BAY 81-8973: A case series.

BAY 81-8973 is an unmodified, full-length third generation recombinant factor VIII (rFVIII) which offers a more favorable pharmacokinetic (PK) profile, compared to its predecessor sucrose-formulated rFVIII (rFVIII-FS). We here report on a retrospective case series of nine patients affected by hemophilia A (HA), with variable disease severity, bleeding phenotype and comorbidities, to underline our clinical practice on prophylaxis with a recently introduced standard hall-life recombinant Factor VIII. The current case series highlights how the current clinical management of hemophilia is able to personalize treatment in several specific conditions like concomitant illnesses with thrombotic risk and allergic reactions.

How I treat gastrointestinal bleeding in congenital and acquired von Willebrand disease.

Gastrointestinal (GI) bleeding is distinctive of severe von Willebrand disease (VWD), generally arising in older patients; in most cases, blood transfusion and hospitalization are required. The presence of arteriovenous malformations is often described when endoscopic examinations are performed. Patients with congenital type 3, 2A, and 2B are those most frequently affected by this symptom, possibly due to the loss of high-molecular-weight multimers of von Willebrand factor (VWF). GI bleeding can also occur in patients affected by acquired von Willebrand syndrome. Endoscopic examination of the GI tract is necessary to exclude ulcers and polyps or cancer as possible causes of GI bleeding. In congenital VWD, prophylaxis with VWF/factor VIII concentrates is generally started after GI-bleeding events, but this therapy is not always successful. Iron supplementation must be prescribed to avoid chronic iron deficiency. Possible rescue therapies (high-dose statins, octreotide, thalidomide, lenalidomide, and tamoxifen) were described in a few case reports and series; however, surgery may be necessary in emergency situations or if medical treatment fails to stop bleeding. In this article, we present several clinical cases that highlight the clinical challenges of these patients and possible strategies for their long-term management.

The Immune Response to the fVIII Gene Therapy in Preclinical Models.

Neutralizing antibodies to factor VIII (fVIII), referred to as "inhibitors," remain the most challenging complication post-fVIII replacement therapy. Preclinical development of novel fVIII products involves studies incorporating hemophilia A (HA) and wild-type animal models. Though immunogenicity is a critical aspect of preclinical pharmacology studies, gene therapy studies tend to focus on fVIII expression levels without major consideration for immunogenicity. Therefore, little clarity exists on whether preclinical testing can be predictive of clinical immunogenicity risk. Despite this, but perhaps due to the potential for transformative benefits, clinical gene therapy trials have progressed rapidly. In more than two decades, no inhibitors have been observed. However, all trials are conducted in previously treated patients without a history of inhibitors. The current review thus focuses on our understanding of preclinical immunogenicity for HA gene therapy candidates and the potential indication for inhibitor treatment, with a focus on product- and platform-specific determinants, including fVIII transgene sequence composition and tissue/vector biodistribution. Currently, the two leading clinical gene therapy vectors are adeno-associated viral (AAV) and lentiviral (LV) vectors. For HA applications, AAV vectors are liver-tropic and employ synthetic, high-expressing, liver-specific promoters. Factors including vector serotype and biodistribution, transcriptional regulatory elements, transgene sequence, dosing, liver immunoprivilege, and host immune status may contribute to tipping the scale between immunogenicity and tolerance. Many of these factors can also be important in delivery of LV-fVIII gene therapy, especially when delivered intravenously for liver-directed fVIII expression. However, ex vivo LV-fVIII targeting and transplantation of hematopoietic stem and progenitor cells (HSPC) has been demonstrated to achieve durable and curative fVIII production without inhibitor development in preclinical models. A critical variable appears to be pre-transplantation conditioning regimens that suppress and/or ablate T cells. Additionally, we and others have demonstrated the potential of LV-fVIII HSPC and liver-directed AAV-fVIII gene therapy to eradicate pre-existing inhibitors in murine and canine models of HA, respectively. Future preclinical studies will be essential to elucidate immune mechanism(s) at play in the context of gene therapy for HA, as well as strategies for preventing adverse immune responses and promoting immune tolerance even in the setting of pre-existing inhibitors.

Comparing Physician and Patient Perspectives on Prophylactic Treatment with BAY 94-9027 for Severe Haemophilia A: A Post Hoc Analysis.

INTRODUCTION: BAY 94-9027 is a newly developed extended half-life product to treat haemophilia, allowing for fewer injections than with standard products. This post hoc analysis aimed to compare physicians' and patients' opinions on BAY 94-9027 prophylaxis, and explore how qualitative interview data is aligned with the data from the Haemophilia-specific Quality of Life questionnaire for Adults (Haemo-QoL-A). METHODS: Exploratory qualitative interviews were conducted with physicians and patients by phone upon the exit of patients from the PROTECT VIII extension phase following a semi-directed guide. In this post hoc analysis, all transcripts were reviewed and reported concepts were compared to assess the level of concordance between physicians and patients. These qualitative data were compared with the Haemo-QoL-A mean global and subscale scores at baseline and end of main phase (36 weeks later). RESULTS: Ten physicians and 16 patients (mean age 47 years) from Israel, the Netherlands and the USA were interviewed. Significant improvements were reported by all physicians from baseline [e.g. lower frequency of bleeds (80%), improvement in emotional functioning (90%)], which is in concordance with patients' reports. The improved confidence reported by physicians cascaded to greater participation in various activities, resulting in a better perceived emotional state and a significant improvement on the Haemo-QoL-A emotional impact subscale score (p = 0.04) between baseline and end of main phase. Most physicians (80%) reported improvement in bleed frequency, as patients did (88%). Improvement in physical functioning or mobility was not consistently reported in this 8-month study. CONCLUSION: Interviewed physicians and patients generally agreed on the beneficial impact of BAY 94-9027, specifically regarding the increased level of self-confidence in patients and its subsequent positive impact on patients' lives. These findings supported the observed improvement on the Haemo-QoL-A emotional impact subscale. Overall, this study highlights the concordance between physician and patient perspective on the positive experience with BAY 94-9027.

Escape or Fight: Inhibitors in Hemophilia A.

Replacement therapy with coagulation factor VIII (FVIII) represents the current clinical treatment for patients affected by hemophilia A (HA). This treatment while effective is, however, hampered by the formation of antibodies which inhibit the activity of infused FVIII in up to 30% of treated patients. Immune tolerance induction (ITI) protocols, which envisage frequent infusions of high doses of FVIII to confront this side effect, dramatically increase the already high costs associated to a patient's therapy and are not always effective in all treated patients. Therefore, there are clear unmet needs that must be addressed in order to improve the outcome of these treatments for HA patients. Taking advantage of preclinical mouse models of hemophilia, several strategies have been proposed in recent years to prevent inhibitor formation and eradicate the pre-existing immunity to FVIII inhibitor positive patients. Herein, we will review some of the most promising strategies developed to avoid and eradicate inhibitors, including the use of immunomodulatory drugs or molecules, oral or transplacental delivery as well as cell and gene therapy approaches. The goal is to improve and potentiate the current ITI protocols and eventually make them obsolete.

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.

PROTECT VIII Kids: BAY 94-9027 (PEGylated Recombinant Factor VIII) safety and efficacy in previously treated children with severe haemophilia A.

INTRODUCTION: BAY 94-9027, a site-specifically PEGylated, B-domain-deleted recombinant factor VIII (FVIII) with extended half-life, demonstrated efficacy for bleed prevention and treatment in previously treated adolescents and adults with severe haemophilia A. AIM: To assess BAY 94-9027 in children with severe haemophilia A. METHODS: In the two-part PROTECT VIII Kids study, boys <12 years with <1% FVIII and >50 exposure days (EDs) to FVIII were enrolled in two cohorts (<6 years; 6-<12 years) and treated with BAY 94-9027 prophylaxis twice-weekly, every 5 days, or every 7 days at physician discretion for ≥50 EDs (Part 1) or twice-weekly for 12-weeks (Part 2). Annualized bleeding rate (ABR) was a primary efficacy endpoint; FVIII inhibitor development was the primary safety variable. RESULTS: At study completion, 25 patients had been treated twice-weekly, 28 in the every-5-day group, and 8 in the every-7-day group. Median ABR for all bleeds was 2.9 (Part 1) and 2.4 (Part 2) and similar in younger and older patients; median ABR for joint bleeds was 0 for both cohorts. In the last 90 days' treatment, median ABR was 0 for younger and older patients (Part 1). Of 149 reported bleeds, 93% were treated with ≤2 infusions. Twelve patients, the majority <6 years (n = 11), discontinued due to apparent loss of efficacy or hypersensitivity. No FVIII inhibitors developed. CONCLUSIONS: In PROTECT VIII Kids, which allowed tailoring of prophylaxis to individual clinical response, BAY 94-9027 was efficacious for bleed prevention and treatment in previously treated children with severe haemophilia A.

BAY 81-8973 demonstrated efficacy, safety and joint status improvement in patients with severe haemophilia A in the LEOPOLD I extension for ≤2 years.

OBJECTIVES: BAY 81-8973 (Kovaltry® ), a full-length, unmodified, recombinant human factor VIII, provided excellent bleeding control for patients with haemophilia A in the pivotal 1-year LEOPOLD I trial. The LEOPOLD I extension evaluated long-term efficacy and safety of BAY 81-8973 prophylaxis. METHODS: After completing LEOPOLD I, patients continued receiving 20-50 IU/kg BAY 81-8973 two- or three-times weekly in the extension. Outcomes included annualised bleeding rate (ABR) and haemostasis during surgery. RESULTS: Fifty-five patients aged 12-65 years participated in the extension. Median (range) exposure days during the 2-year total study period was 309 (115-355). No patient switched regimens. Median (Q1; Q3) ABR for all bleeds was 2.0 (1.0; 6.1) during the pivotal study, 2.0 (0.0; 5.2) during the extension, and 2.0 (0.5; 5.5) combined. The proportion of joint bleeds affecting target joints decreased (pivotal study: 90.9%, extension: 60.0%). Haemostasis was assessed as excellent/good in all five major surgeries. One serious adverse event (myocardial infarction) occurred in a patient with cardiovascular risk factors. No patients developed inhibitors. CONCLUSIONS: BAY 81-8973 prophylaxis efficacy outcomes in the pivotal study were maintained or, in the case of joint protection, improved during the extension, with a safety and tolerability profile consistent with previous experience.

Reducing the effect of DOAC interference in laboratory testing for factor VIII and factor IX: A comparative study using DOAC Stop and andexanet alfa to neutralize rivaroxaban effects.

INTRODUCTION: Investigation of factors (F) VIII and IX is common, with testing important for diagnosis or exclusion of haemophilia A or B, associated acquired conditions and factor inhibitors. Rivaroxaban, a common direct anti-Xa agent, causes significant interference in clotting assays, including substantial false reduction of factor levels. AIM: To assess whether rivaroxaban-induced interference of FVIII and FIX testing could be neutralized. MATERIALS AND METHODS: An international, cross-laboratory exercise for FVIII (n = 84) and FIX (n = 74), using four samples: (A) pool of normal plasma; (B) pool spiked with rivaroxaban (200 ng/mL); (C) rivaroxaban sample subsequently treated with 'DOAC Stop' and; (D) rivaroxaban sample treated with andexanet alfa (200 µg/mL). Testing performed blind to sample type. RESULTS: All laboratories reported normal FIX and 94% reported normal FVIII in the pool sample. Instead, 55% and 95%, respectively, reported abnormal FIX and FVIII levels for the rivaroxaban sample. DOAC Stop treatment evidenced a correction in most laboratories (100% reported normal FIX and 86% normal FVIII). Andexanet alfa provided intermediate results, with many laboratories still reporting abnormal results (59% for FVIII, 18% for FIX). We also identified reagent-specific issues. CONCLUSIONS: As expected, rivaroxaban caused false low values of FVIII and FIX. This might lead to increased testing to identify the cause of low factor levels and potentially lead to false identification of (mild) haemophilia A or B if unrecognized by clinicians/laboratories. DOAC Stop effectively neutralized the rivaroxaban effect, but andexanet alfa less so, with reagent-related effects evident, and thus, false low values sometimes persisted.

Assessing prophylactic use and clinical outcomes in hemophilia A patients treated with rVIII-SingleChain and other common rFVIII products in Germany.

OBJECTIVE: To evaluate real-world outcomes with rVIII-SingleChain and other commonly used recombinant FVIII (rFVIII) products. METHODS: Hemophilia treatment centers in Germany (n = 21) contributed patient chart data. Inclusion criteria were prophylactic treatment with one of five rFVIII products for ≥8 weeks. RESULTS: Male patients (n = 225) were included: rVIII-SingleChain (n = 40), rFVIIIFc (n = 47), octocog alfa (rFVIII; n = 58), octocog alfa (BAY 81-8973; n = 40), or moroctocog alfa (n = 40). In patients with severe disease (n = 76), 66.6%, 70.0%, 20.0%, 7.7%, and 27.3% were dosed ≤2×/week, respectively. Irrespective of dosing frequency, mean annualized bleed rates (ABRs)/annualized spontaneous bleed rates (AsBRs) were 0.3/0.1, 0.8/0.4, 1.1/0.5, 1.5/0.8, and 1.4/0.6, and mean FVIII consumption (IU/kg/week) was 83.2, 97.2, 92.5, 104.0, and 102.1, respectively. Results for all patients were similar. Of the patients on prophylaxis with prior therapy and after switching to rVIII-SingleChain (n = 21), mean ABR/AsBRs were 0.7/0.3 and 0.2/0.0, respectively. After switching to rVIII-SingleChain, mean FVIII consumption reduced (109.4 vs 74.5 IU/kg/week), and percentage of patients dosed ≤2×/week increased (0% to 71.4%). CONCLUSIONS: rVIII-SingleChain prophylaxis provides excellent bleeding protection, with potentially lowest factor consumption among the products assessed. Patients who switched to rVIII-SingleChain prophylaxis reduced dosing frequency and consumption compared with prior treatment, with similar or potentially lower bleeding rates.

Safety and efficacy of BAY 94-9027, an extended-half-life factor VIII, during surgery in patients with severe hemophilia A: Results of the PROTECT VIII clinical trial.

INTRODUCTION: Ensuring hemostasis during invasive procedures is a challenge in patients with severe hemophilia A. This analysis evaluated efficacy and safety of BAY 94-9027, an extended-half-life recombinant factor VIII (FVIII), in the surgical setting. MATERIALS AND METHODS: Patients participating in an open-label BAY 94-9027 clinical trial who underwent major surgery were included in the analysis. Investigator/surgeon assessment of hemostasis during surgery was the primary outcome. In addition, information about FVIII use, FVIII levels during perioperative period, bleeding complications and FVIII inhibitor development were collected. RESULTS: Data were analyzed for 26 major surgeries (orthopedic, n = 21) in 20 patients aged 13-61 years. BAY 94-9027 provided effective hemostasis during all procedures. FVIII levels 6-8 h post preoperative infusion and prior to the first follow-up infusion were in the range expected to maintain protection in the major surgery setting. The median time from preoperative infusion to the first follow-up infusion (the first infusion administered after the preoperative infusion) was 12.33 (3.6-49.9) h. No intraoperative bleeding complications occurred, and no new inhibitors developed following any surgery. CONCLUSIONS: The results of the study demonstrate that BAY 94-9027 was efficacious and well tolerated in the treatment of patients undergoing major surgeries. Advantages of BAY 94-9027 include the potential for less frequent infusion and reduced factor consumption, which should simplify the management of patients during major surgery.