Emicizumab prophylaxis in people with hemophilia A and inhibitors: a systematic review and meta-analysis

ABSTRACT BACKGROUND: Until recently, the treatment of people with hemophilia A and inhibitors (PwHAi) was based on the use of bypassing agents (BPA). However, the advent of emicizumab as prophylaxis has demonstrated promising results. OBJECTIVES: We aimed to compare the bleeding endpoints between PwHAi on BPA and those on emicizumab prophylaxis. DESIGN AND SETTING: Systematic review of interventions and meta-analysis conducted at the Universidade Federal de Goiás, Goiânia, Goiás, Brazil. METHODS: The CENTRAL, MEDLINE, Scopus, and LILACS databases were searched on February 21, 2023. Two authors conducted the literature search, publication selection, and data extraction. The selected publications evaluated the bleeding endpoints between PwHAi on emicizumab prophylaxis and those on BPA prophylaxis. The risk of bias was evaluated according to the Joanna Briggs Institute criteria. A meta-analysis was performed to determine the annualized bleeding rate (ABR) for treated bleeds. RESULTS: Five publications (56 PwHAi) were selected from the 543 retrieved records. Overall, bleeding endpoints were lower during emicizumab prophylaxis than during BPA prophylaxis. All the publications had at least one risk of bias. The only common parameter for the meta-analysis was the ABR for treated bleeds. During emicizumab prophylaxis, the ABR for treated bleeds was lower than during BPA prophylaxis (standard mean difference: −1.58; 95% confidence interval −2.50, −0.66, P = 0.0008; I2 = 68.4%, P = 0.0031). CONCLUSION: Emicizumab was superior to BPA in bleeding prophylaxis in PwHAi. However, both the small population size and potential risk of bias should be considered when evaluating these results. SYSTEMATIC REVIEW REGISTRATION: CRD42021278726, https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=278726.

Efficacy/effectiveness and safety of emicizumab prophylaxis of people with hemophilia A: a systematic review and meta-analysis.

BACKGROUND: Emicizumab is a monoclonal antibody approved for prophylaxis against bleeds for people with hemophilia A (PwHA). A systematic review was conducted evaluating the efficacy/effectiveness and the safety of emicizumab as prophylaxis for PwHA compared to prophylaxis with factor VIII (FVIII) or bypassing agents (BPA), respectively in patients without and with inhibitors. RESEARCH DESIGN AND METHODS: Database-directed search strategies were performed in Aug/26/2022 and updated in Mar/16/2023. Studies evaluating the prophylaxis with emicizumab versus prophylaxis with FVIII or BPA in PwHA without or with inhibitors, respectively, were selected by two independent reviewers. Data were extracted by two independent reviewers. Annualized bleeding rates for total treated bleeding events (ABR-all) were evaluated by meta-analysis. The quality of studies and certainty of evidence were assessed. RESULTS: A total of 11 studies were included. The standard mean differences for ABR-all were -0.6 (95%CI -1.0 to -0.2, p-value = 0.0002), among PwHA without inhibitors, and -1.7 (95%CI -2.4 to -0.9, p-value <0.00001), among PwHA with inhibitors. However, there was moderate heterogeneity in both meta-analyses. The most frequent adverse event was injection site reaction. CONCLUSIONS: Emicizumab prophylaxis was superior in reducing the ABR-all when compared with prophylaxis with FVIII or BPA.

Emicizumab prophylaxis for people with hemophilia A: Waste estimation and the Brazilian perspective.

Costs of hemophilia A treatment are increasing. Waste of clotting products should be avoided. To estimate the first-year waste of emicizumab prophylaxis for people with hemophilia A and inhibitors (PwHAi) who failed immune tolerance induction (ITI), in Brazil. We evaluated the manufacturer and the Brazilian Ministry of Health (MoH) protocol-recommended regimens in a budget impact model. The loading dose consisted of 3.0 mg/kg/Q1W for 4 weeks, for both recommendations. The manufacturer maintenance regimens comprised 1.5 mg/kg/Q1W, 3.0 mg/kg/Q2W, and 6.0 mg/kg/Q4W. The MoH protocol maintenance regimen encompassed a hybrid Q1W/Q2W administration, depending on the body weight. The Q4W regimen was not recommended by the MoH protocol. Analyses were performed to estimate waste given its expense based on the World Health Organization body weight range (percentiles [P] 15, 50, and 85). The first-year emicizumab waste was estimated individually and for the disclosed PwHAi who failed ITI (n = 114). The highest emicizumab waste was estimated for the lowest body weights and the Q1W regimen. The Q4W regimen resulted in the lowest emicizumab waste, followed by the MoH protocol regimen. The total reconstituted costs estimated for the PwHAi who failed ITI according to the hybrid MoH protocol ranged from US$32,858,777 (P15) to US$47,186,858 (P85), with emicizumab waste ranging from 7.9 % (US$2,594,515) to 3.7 % (US$1,738,750), respectively. Lost resources due to current protocols for emicizumab prophylaxis for PwHAi who failed ITI in Brazil are considerable. Waste was more pronounced due to lower body weight and shorter administration intervals.

Validación de un método para la cuantificación plasmática de emicizumab / Validation of a method for plasma quantification of emicizumab

Resumen Introducción: El emicizumab (Hemlibra®, ROCHE) es un anticuerpo monoclonal IgG4 bi-específico, recombinante y humanizado, que mimetiza la función del FVIIIa. Su administración por vía subcutánea es eficaz y segura en la prevención de hemorragias en pacientes con hemofilia A severa con o sin inhibidor. Si bien el emicizumab ha sido aprobado con un régimen de administración basado en el peso corporal y sin un monitoreo de los niveles plasmáticos, la cuantificación plasmática de emicizumab puede ser útil en distintas circunstancias clínicas y de investigación. Debido a que en Argentina aún no están disponibles los calibradores y controles comerciales específicos de emicizumab, hemos validado un método para la cuantificación plasmática de emicizumab (Epc), basado en la medición de FVIII por método coagulométrico en una etapa modificado (modFVIIIcoag), utilizando calibradores y controles preparados "in-house". Materiales y métodos: para la Epc se utilizó una predilución de la muestra 1/80 con buffer Owren Koller. El calibrador "in-house" de emicizumab (150 μg/mL de emicizumab) se preparó agregando emicizumab de 150 mg/ml a un plasma deficiente en FVIII. Se prepararon dos niveles de control "in-house" y una curva de calibración de 6 puntos. Los procedimientos de validación se realizaron en un STA Compact Max2 (Diagnostica Stago). Repetibilidad: se procesaron los controles 20 veces en la misma corrida analítica. Imprecisión Intra-Laboratorio: se procesaron los controles por triplicado durante 5 días. Linealidad:11 niveles medidos por triplicado. Límite de cuantificación: 15 mediciones de un plasma deficiente de FVIII comercial. Bias: a partir de un programa de evaluación externa de calidad (UK NEQAS). Se evaluó la interferencia del FVIII y rFVIIa en Epc, y de emicizumab en otras determinaciones de hemostasia. Resultados: Epc mostró una imprecisión y un sesgo aceptables, un rango lineal de 5-150 µg/ml y un límite de cuantificación de 5 µg/ml de emicizumab. En los estudios de interferencia se encontró que el FVIII interfiere con Epc pero no así el rFVIIa. Emicizumab acortó los valores del TTPa por debajo del límite inferior del intervalo de referencia local, mientras que el FVIII medido por método cromogénico con componentes de origen bovino no fue afectado. El método coagulométrico de una etapa de FVIII fue falsamente aumentado y mostró una fuerte correlación lineal con Epc en este sistema reactivo/instrumento. Discusión: El ensayo modFVIIIcoag automatizado "in-house" permite la cuantificación plasmática de emicizumab mediante un método sencillo, reproducible, de bajo costo y de fácil integración en los procesos de rutina.

Abstract Introduction: Emicizumab (Hemlibra®, ROCHE) is a bispecific, recombinant and humanized IgG4 monoclonal antibody, that mimics the function of FVIIIa. Its subcutaneous administration is effective and safe in preventing bleeding in patients with severe hemophilia A with or without inhibitor. Although emicizumab has been approved with an administration regimen based on body weight and without monitoring of plasma levels, emicizumab plasma quantification may be useful in different clinical and research circumstances. Since emicizumab-specific commercial calibrators and controls are not yet available in Argentina, we have validated a modified one-stage FVIII assay (modOSA) for the quantification of emicizumab in plasma (Epq) using in-house prepared calibrators and controls. Materials and methods: For Epq a 1/80 sample predilution with Owren Koller buffer was used. In house emicizumab calibrator (150 μg/mL emicizumab) was prepared by adding emicizumab 150 mg/mL to FVIII deficient plasma. Two in house control levels and a 6-point calibration curve were prepared. The validation procedures were performed in a STA Compact Max2 analyser (Diagnostica Stago). Repeatability: controls were processed 20 times in the same analytical run. Intra-laboratory Imprecision:controls were processed in triplicate for 5 days. Linearity: 11 levels were measured in triplicate. Limit of quantitation: 15 measurements of a commercial FVIII deficient plasma were assessed. Bias were estimated based on an external quality assessment program (UK NEQAS). The interference of FVIII and rFVIIa in Epq and of emicizumab in other hemostasis determinations were evaluated. Results: Epq showed acceptable imprecision and bias, a linear range of 5-150 µg/ml and a quantification limit of 5 µg/ml. Epq was interfered with FVIII but not with rFVIIa. Emicizumab shortened aPTT values below the lower limit of the local reference interval. FVIII measured by chromogenic method with components of bovine origin was not affected. The one-stage FVIII assay (OSA) was falsely increased but showed a strong linear correlation with Epq in this instrument reagent system. Discussion: The automated "in-house" modOSA allows the plasma quantification of emicizumab using a simple, reproducible, low-cost method that is easy to integrate into routine processes.

Immunogenicity of Current and New Therapies for Hemophilia A.

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

Statements about hemophilia A in Brazil: an expert Delphi panel / Consensos em hemofilia A no Brasil: painel Delphi de especialistas

Objective: Understanding unmet needs related to hemophilia A management in Brazil is critical for supporting decision-making. Methods: A modified Delphi consensus panel was conducted. Hematologists with extensive experience treating hemophilia in the Brazilian Public Health System were invited to answer questions regarding indicators of severe hemophilia prophylaxis effectiveness, emicizumab treatment indications, and bypassing agents used to reduce bleeding in patients with inhibitors, immune tolerance induction (ITI) use, and adherence. The consensus was defined as ≥75% of votes in Round 1 or using a 5-point Likert-type scale (1 = strongly disagree, 2 = disagree, 3 = neither agree nor disagree, 4 = agree, and 5 = strongly agree) in Round 2, which included questions not reaching minimum cut-off in the first step. Results: Nine expert panelists with extensive experience in the Brazilian Public Health System participated. The panel reached an agreement on recommendations about prophylaxis, bleeding treatment patterns, and bleeding sites. From patients' perspectives, venous access and infusion frequency were the most significant barriers to improving patient treatment. According to most experts, emicizumab will not replace ITI or long-term factor VIII therapy. Still, emicizumab was thought to be a good therapeutic option for patients with difficult venous access, patients requiring central venous access, in the presence of inhibitors, or patients experiencing infusion-related pain. Conclusion: The information gleaned from this study may be helpful to both decision-makers and those in charge of developing healthcare economic models for the treatment of hemophilia A in Brazil.

Objetivo: É fundamental entender as necessidades não atendidas relacionadas ao manejo da hemofilia A no Brasil. Métodos: Foi conduzido um painel Delphi modificado. Foram convidados hematologistas com vasta experiência no tratamento de hemofilia no SUS para responder a perguntas sobre indicadores de eficácia da profilaxia, indicações de tratamento com emicizumabe, uso de agentes de bypass, uso de indução de tolerância imunológica (ITI) e adesão. O consenso foi definido como ≥75% dos votos na rodada 1 ou usando uma escala do tipo Likert de 5 pontos (1 = discordo totalmente, 2 = discordo, 3 = não concordo nem discordo, 4 = concordo e 5 = concordo totalmente) na segunda rodada, que incluiu questões que não atingiram o corte mínimo na primeira etapa. Resultados: Nove especialistas participaram e houve consenso sobre recomendações para profilaxia, padrões de tratamento de sangramento e locais de sangramento. O acesso venoso e a frequência da infusão foram identificados como as barreiras mais significativas para melhorar o tratamento do paciente. De acordo com a maioria, emicizumabe não substituirá a ITI ou tratamento com fator VIII de longo prazo. Emicizumabe foi considerado uma boa opção terapêutica para

Cost-effectiveness study of prophylaxis with emicizumab versus bypassing agents in patients with severe hemophilia A in Peru. / Estudio de costo-efectividad de profilaxis con emicizumab versus agentes hemostáticos alternativos en pacientes con hemofilia A grave en Perú.

Settings: Hemophilia is a coagulation disorder that occurs in one in 5000 male births. Patients with untreated severe hemophilia A have hemorrhagic complications, including joint bleeds and decreased survival. Emicizumab is a monoclonal antibody approved by the United States for routine prophylaxis of pediatric and adult patients with severe hemophilia A with factor VIII inhibitors. Objectives: To perform a cost-effectiveness study of emicizumab prophylaxis for children and adults with severe hemophilia A compared with the current disease management in the Peruvian Ministry of Health and Social Security Health Insurance. Methods: The patient transition between medical states was modeled with Markov methodology, and the lifetime costs and incremental effects of emicizumab compared to current management were estimated. The budgetary impact of emicizumab was estimated by projecting annual net costs and its five-year present value. Results: In the Ministry of Health, emicizumab would generate savings between 14.6 and 16.0 per child and 11.8 per adult, in current US$ million. Social Security Health Insurance savings would be 12.8 to 14.9 per child and 40.1 per adult. In addition, this strategy would generate effectiveness gains, measured in quality-adjusted life-years, of 0.36 per child and 0.56 per adult and 0.25 per child, and 0.36 per adult in those respective institutions. The budgetary impact would be a net annual saving of 12.8 and 15.0 US$ million in those entities. Conclusions: The current management of hemophilia A is very costly and has health outcomes inferior to those possible with emicizumab. This drug would produce significant savings and better patient health. The Ministry of Health and Social Health Insurance should implement hemophilia prophylaxis and treatment protocols and finance this drug.

Contexto: La hemofilia es un trastorno hemorrágico de la coagulación que ocurre en uno de cada 5000 nacimientos masculinos. Los pacientes con hemofilia A grave no tratados tienen complicaciones hemorrágicas, incluyendo sangrados articulares y menor sobrevida. El emicizumab es un anticuerpo monoclonal aprobado por los Estados Unidos para la profilaxis rutinaria de pacientes pediátricos y adultos con hemofilia A grave con inhibidores del factor VIII de coagulación. Objetivos: Realizar un estudio de costo-efectividad de la profilaxis con emicizumab para niños y adultos con hemofilia A grave, en comparación con el actual manejo de esos pacientes en el Ministerio de Salud y el Seguro Social de Salud de Perú. Metodología: Se modeló la transición del paciente entre estados médicos con la metodología de Markov y se estimó a lo largo de su vida costos y efectos incrementales de emicizumab comparados con el actual manejo. Se estimó el impacto presupuestario de emicizumab proyectando costos netos anuales y su valor presente a cinco años. Resultados: Emicizumab generaría ahorros en el Ministerio de Salud entre 14,6 y 16,0 por niño y 11,8 por adulto, en US$ millones actuales, y en el Seguro Social de Salud de 12,8 a 14,9 por niño y 40,1 por adulto. Además, se generan ganancias en efectividad, medidas en años de vida ajustados por calidad, de 0,36 por niño y 0,56 por adulto y de 0,25 por niño y 0,36 por adulto en esas respectivas instituciones. El impacto presupuestario sería un ahorro anual neto, en US$ millones, de 12,8 y 15,0 en esas entidades. Conclusión: El actual manejo de la enfermedad es muy costoso y con resultados de salud inferiores a los posibles con emicizumab. Este fármaco produciría grandes ahorros y mejor salud. Ambas entidades debieran implementar protocolos para la profilaxis y tratamiento de la hemofilia y financiarla con presupuesto propio.

Estudio de costo-efectividad de profilaxis con emicizumab versus agentes hemostáticos alternativos en pacientes con hemofilia A grave en Perú / Cost-effectiveness study of prophylaxis with emicizumab versus bypassing agents in patients with severe hemophilia A in Peru

Contexto La hemofilia es un trastorno hemorrágico de la coagulación que ocurre en uno de cada 5000 nacimientos masculinos. Los pacientes con hemofilia A grave no tratados tienen complicaciones hemorrágicas, incluyendo sangrados articulares y menor sobrevida. El emicizumab es un anticuerpo monoclonal aprobado por los Estados Unidos para la profilaxis rutinaria de pacientes pediátricos y adultos con hemofilia A grave con inhibidores del factor VIII de coagulación. Objetivos Realizar un estudio de costo-efectividad de la profilaxis con emicizumab para niños y adultos con hemofilia A grave, en comparación con el actual manejo de esos pacientes en el Ministerio de Salud y el Seguro Social de Salud de Perú. Metodología Se modeló la transición del paciente entre estados médicos con la metodología de Markov y se estimó a lo largo de su vida costos y efectos incrementales de emicizumab comparados con el actual manejo. Se estimó el impacto presupuestario de emicizumab proyectando costos netos anuales y su valor presente a cinco años. Resultados Emicizumab generaría ahorros en el Ministerio de Salud entre 14,6 y 16,0 por niño y 11,8 por adulto, en US$ millones actuales, y en el Seguro Social de Salud de 12,8 a 14,9 por niño y 40,1 por adulto. Además, se generan ganancias en efectividad, medidas en años de vida ajustados por calidad, de 0,36 por niño y 0,56 por adulto y de 0,25 por niño y 0,36 por adulto en esas respectivas instituciones. El impacto presupuestario sería un ahorro anual neto, en US$ millones, de 12,8 y 15,0 en esas entidades. Conclusión El actual manejo de la enfermedad es muy costoso y con resultados de salud inferiores a los posibles con emicizumab. Este fármaco produciría grandes ahorros y mejor salud. Ambas entidades debieran implementar protocolos para la profilaxis y tratamiento de la hemofilia y financiarla con presupuesto propio.

Settings Hemophilia is a coagulation disorder that occurs in one in 5000 male births. Patients with untreated severe hemophilia A have hemorrhagic complications, including joint bleeds and decreased survival. Emicizumab is a monoclonal antibody approved by the United States for routine prophylaxis of pediatric and adult patients with severe hemophilia A with factor VIII inhibitors. Objectives To perform a cost-effectiveness study of emicizumab prophylaxis for children and adults with severe hemophilia A compared with the current disease management in the Peruvian Ministry of Health and Social Security Health Insurance. Methods The patient transition between medical states was modeled with Markov methodology, and the lifetime costs and incremental effects of emicizumab compared to current management were estimated. The budgetary impact of emicizumab was estimated by projecting annual net costs and its five-year present value. Results In the Ministry of Health, emicizumab would generate savings between 14.6 and 16.0 per child and 11.8 per adult, in current US$ million. Social Security Health Insurance savings would be 12.8 to 14.9 per child and 40.1 per adult. In addition, this strategy would generate effectiveness gains, measured in quality-adjusted life-years, of 0.36 per child and 0.56 per adult and 0.25 per child, and 0.36 per adult in those respective institutions. The budgetary impact would be a net annual saving of 12.8 and 15.0 US$ million in those entities. Conclusions The current management of hemophilia A is very costly and has health outcomes inferior to those possible with emicizumab. This drug would produce significant savings and better patient health. The Ministry of Health and Social Health Insurance should implement hemophilia prophylaxis and treatment protocols and finance this drug.

Primera experiencia de tratamiento con emicizumab en un paciente con hemofilia A severa e inhibidor de alto título en Uruguay / First report of emicizumab use in a patient with severe haemophilia A and high-titer inhibitor in Uruguay / Primeira experiência de tratamento com emicizumab em paciente com hemofilia A grave e inibidor de alto título no Uruguai

La hemofilia A es una coagulopatía congénita causada por la deficiencia o el mal funcionamiento del factor VIII de la coagulación. Una de las complicaciones más graves del tratamiento de la hemofilia A es el desarrollo de inhibidores que hacen que la terapia de reemplazo con FVIII sea ineficaz, dificultando la prevención y el control de los sangrados. El emicizumab es un anticuerpo monoclonal humanizado biespecífico dirigido contra los factores FIXa y FX, que imita la función de cofactor del FVIII. El tratamiento profiláctico con emicizumab es seguro y eficaz para prevenir hemorragias en los pacientes con hemofilia A con y sin inhibidores. Se presenta el caso del primer paciente tratado con emicizumab en Uruguay.

Haemophilia A is a congenital coagulopathy caused by a deficiency or malfunction of coagulation factor VIII. One of the most serious complications of haemophilia A treatment is the development of inhibitors that render FVIII replacement therapy ineffective, making it difficult to prevent and control bleeding. Emicizumab is a humanized bispecific monoclonal antibody directed against factors FIXa and FX, which mimics the cofactor function of FVIII. Emicizumab has been shown to be safe and effective as prophylaxis to prevent bleeding in haemophilia A patients with or without inhibitors to FVIII. We report the first patient treated with emicizumab in Uruguay.

A hemofilia A é uma coagulopatia congênita que se caracteriza pela ausência ou mau funcionamento do factor VIII da coagulação. Uma das complicações mais sérias do tratamento da hemofilia A é o desenvolvimento de inibidores que tornam a terapia de reposição do FVIII ineficaz, dificultando a prevenção e o controle do sangramento. O emicizumab é um anticorpo monoclonal biespecífico humanizado dirigido contra os fatores FIXa e FX, que imita a função de cofator do FVIII. O tratamento profilático com emicizumab é seguro e eficaz na prevenção de sangramento em pacientes com hemofilia A com e sem inibidores. É apresentado o caso do primeiro paciente tratado com emicizumabe no Uruguai.