Investigational drugs for immune thrombocytopenia.

INTRODUCTION: Primary immune thrombocytopenia (ITP) is an acquired autoimmune disease of unknown cause. Autoantibodies, self-reactive T cells and other immune abnormalities, with impairment of platelet production, lead to a reduced platelet count. Until recently, therapy was largely empirical using immune suppressants (none of which have undergone randomized clinical trials). These therapies have variable efficacy and are associated with predictable unwanted effects which impact patient quality-of-life. With greater understanding of the underlying pathophysiology, better, more targeted therapies have been developed; however, there is still an urgent need for additional classes of treatment. AREAS COVERED: This article covers new TPO receptor agonists, Syk inhibitors, Fcγ receptor antagonists, BTK and complement inhibitors, and other therapies. Insights into the most promising therapies are offered. Novel ITP treatments currently in clinical trials and those recently approved come under the spotlight. EXPERT OPINION: Thrombopoietin receptor agonists remain the most effective treatment for ITP and have changed the ITP therapeutic landscape remarkably. Other new molecules such as Fcγ receptor blockers, Bruton tyrosine kinase, complement inhibitors, and others are unlikely to enjoy the same success rate as the TPO-RAs, but nonetheless they will find a place in the management of patients with ITP.

A real-world study of immune thrombocytopenia management during the COVID-19 pandemic in the UK.

The COVID-19 pandemic has created many challenges in the management of immune thrombocytopenic purpura (ITP). The recommendation for avoidance of steroids by WHO led to the off-licence use, supported by NHS England, of thrombopoietin mimetics (TPO-RA) for newly diagnosed or relapsed ITP. This is a real-world prospective study which investigated the treatment patterns and outcomes in this setting. Twenty-four hospitals across the UK submitted 343 cases. Corticosteroids remain the mainstay of ITP treatment, but TPO-RAs were more effective. Incidental COVID-19 infection was identified in a significant number of patients (9·5%), while 14 cases were thought to be secondary to COVID-19 vaccination.

Treatment of severe thrombocytopenia associated with systemic lupus erythematosus in pregnancy with eltrombopag: A case report and literature review.

WHAT IS KNOWN AND OBJECTIVE: Severe thrombocytopenia associated with systemic lupus erythematosus (SLE) in pregnancy is infrequent. Its occurrence can lead to serious adverse pregnancy consequences and perinatal complications. The thrombopoietin (TPO) analogue eltrombopag has been successfully used in the treatment of autoimmune thrombocytopenia, but its safety and efficacy in severe thrombocytopenia during pregnancy remain unclear. CASE SUMMARY: We report a 33-year-old woman with SLE at 29 + 3 weeks gestational age who developed severe thrombocytopenia with complaints of epistaxis, gum bleeding and haematuresis. Most conventional treatments including glucocorticoids, intravenous immunoglobulin (IVIG) and cyclosporine did not elevate her platelets, but eltrombopag worked well and her platelet count gradually recovered, allowing her to deliver a healthy baby at 36 + 3 weeks gestational age. WHAT IS NEW AND CONCLUSION: This suggests that eltrombopag in combination with glucocorticoids has a good safety and efficacy profile in pregnant patients with SLE complicated by severe thrombocytopenia.

AGA Clinical Practice Update: Coagulation in Cirrhosis.

DESCRIPTION: This expert review was commissioned and approved by the AGA Institute Clinical Practice Updates Committee and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership. The intent is to evaluate the current data on mechanism of altered coagulation in patients with cirrhosis, provide guidance on the use of currently available testing of the coagulation cascade, and help practitioners use anticoagulation and pro-coagulants appropriately in patients with cirrhosis. METHODS: This review is framed around the best practice points, which were derived from the most impactful publications in the area of coagulation in cirrhosis and agreed to by all authors. BEST PRACTICE ADVICE 1: Global tests of clot formation, such as rotational thromboelastometry, thromboelastography, sonorheometry, and thrombin generation, may eventually have a role in the evaluation of clotting in patients with cirrhosis, but currently lack validated target levels. BEST PRACTICE ADVICE 2: In general, clinicians should not routinely correct thrombocytopenia and coagulopathy before low-risk therapeutic paracentesis, thoracentesis, and routine upper endoscopy for variceal ligation in patients with hepatic synthetic dysfunction-induced coagulation abnormalities. BEST PRACTICE ADVICE 3: Blood products should be used sparingly because they increase portal pressure and carry a risk of transfusion-associated circulatory overload, transfusion-related acute lung injury, infection transmission, alloimmunization, and/or transfusion reactions. BEST PRACTICE ADVICE 4: The following transfusion thresholds for management of active bleeding or high-risk procedures may optimize clot formation in advanced liver disease: hematocrit ≥25%, platelet count >50,000, and fibrinogen >120 mg/dL. Commonly utilized thresholds for international normalized ratio correction are not supported by evidence. BEST PRACTICE ADVICE 5: Thrombopoietin agonists are a good alternative to platelet transfusion, but require time (about 10 days) to elevate platelet levels. BEST PRACTICE ADVICE 6: The large volume of fresh frozen plasma required to reach an arbitrary international normalized ratio target, limitations of the usual target, minimal effect on thrombin generation, and adverse effects on portal pressure limit the utility of this agent significantly. BEST PRACTICE ADVICE 7: The 4-factor prothrombin complex concentrate contains both pro- and anticoagulant factors that offer an attractive low-volume therapeutic to rebalance a disturbed hemostatic system. However, dosage is, in part, based on international normalized ratio, which is problematic in cirrhosis, and published experience in liver disease is limited. BEST PRACTICE ADVICE 8: Anti-fibrinolytic therapy may be considered in patients with persistent bleeding from mucosal oozing or puncture wound bleeding consistent with impaired clot integrity. Both ε-aminocaproic acid and tranexamic acid inhibit clot dissolution. Neither is believed to generate a hypercoagulable state, although both may exacerbate pre-existing thrombi. BEST PRACTICE ADVICE 9: Desmopressin releases von Willebrand factor as its primary hemostatic mechanism. As this factor is usually elevated in cirrhosis, the agent lacks a sound evidence-based foundation, but may be useful in patients with concomitant renal failure. BEST PRACTICE ADVICE 10: Systemic heparin infusion is recommended for symptomatic deep vein thrombosis and portal and mesenteric vein thrombosis, but there are unresolved issues regarding monitoring with both the anti-Xa assay and the partial thromboplastin time due to cirrhosis-related antithrombin deficiency (heparin cofactor). BEST PRACTICE ADVICE 11: Treatment of incidental portal and mesenteric vein thrombosis depends on estimated impact on transplantation surgical complexity vs risks of bleeding and falls. Therapy with low-molecular-weight heparin, vitamin K antagonists, and direct-acting anticoagulants improve portal vein repermeation vs observation alone. BEST PRACTICE ADVICE 12: Direct-acting anticoagulants, such as the factor Xa and thrombin inhibitors, are relatively safe and effective in stable cirrhotic patients, but are in need of further study in patients with more advanced liver disease.

Successful eltrombopag treatment of severe refractory thrombocytopenia in chronic myelomonocytic leukemia: Two cases reports: A CARE-compliant article.

RATIONALE: Thrombocytopenia in chronic myelomonocytic leukemia (CMML) is usually attributed to impaired marrow production resulting from cytotoxic drug use or CMML itself ("CMML-induced thrombocytopenia"). In very rare cases, immune thrombocytopenia (ITP) can be a complication of CMML ("CMML-associated ITP"). However, treatment of severe thrombocytopenia in patients with CMML is still a challenge. PATIENT CONCERNS: Case 1 was a 61-year-old female patient admitted to our hospital because of skin petechiae and purpura for 6 days. She had increased monocyte cell count (1.82 × 10/L), markedly decreased platelet count (2 × 10/L), hypercellularity of the megakaryocyte lineage with many immature megakaryocytes, and ZRSR2(zinc finger CCCH-type, RNA binding motif and serine/arginine rich 2) mutation. She failed to the treatment of corticosteroids, intravenous immunoglobulin (IVIg), TPO (thrombopoietin), and cyclosporin A (CsA). Case 2 was a 72-year-old female patient with thrombocytosis and monocytosis for 4 years, and thrombocytopenia for 6 months. After 10 courses of decitabine therapy, she had a persistent severe thrombocytopenia and decreased number of megakaryocytes, TET2 (tet methylcytosine dioxygenase 2) and SRSF2 (serine and arginine rich splicing factor 2) mutations were detected. She was dependent on platelet transfusion. DIAGNOSES: Case 1 was diagnosed as CMML-associated ITP, and case 2 as CMML with decitabine therapy-induced thrombocytopenia. INTERVENTIONS: Both patients were treated with eltrombopag. OUTCOMES: In both patients, the platelet counts returned to the normal within 1 week after eltrombopag therapy. The platelet count in case 1 patient remained stable at 141-200 × 10/L for 20 months with stopping therapy for 3 months. In case 2 patient, eltrombopag was stopped 1 month later. Her platelet count decreased to 41 × 10/L, but was stable at ∼30 × 10/L for 3 months with platelet transfusion independency for 12 months. Both patients had no adverse effects with eltrombopag. LESSONS: CMML-associated ITP is very rare and easily misdiagnosed. To the best of our knowledge, case 1 is the first reported case of the successful treatment of CMML-associated ITP with eltrombopag. Both CMML-associated ITP and decitabine therapy-induced thrombocytopenia in these 2 patients were highly sensitive and safe to eltrombopag therapy.

Platelets in liver disease, cancer and regeneration.

Although viral hepatitis treatments have evolved over the years, the resultant liver cirrhosis still does not completely heal. Platelets contain proteins required for hemostasis, as well as many growth factors required for organ development, tissue regeneration and repair. Thrombocytopenia, which is frequently observed in patients with chronic liver disease (CLD) and cirrhosis, can manifest from decreased thrombopoietin production and accelerated platelet destruction caused by hypersplenism; however, the relationship between thrombocytopenia and hepatic pathogenesis, as well as the role of platelets in CLD, is poorly understood. In this paper, experimental evidence of platelets improving liver fibrosis and accelerating liver regeneration is summarized and addressed based on studies conducted in our laboratory and current progress reports from other investigators. In addition, we describe our current perspective based on the results of these studies. Platelets improve liver fibrosis by inactivating hepatic stellate cells, which decreases collagen production. The regenerative effect of platelets in the liver involves a direct effect on hepatocytes, a cooperative effect with liver sinusoidal endothelial cells, and a collaborative effect with Kupffer cells. Based on these observations, we ascertained the direct effect of platelet transfusion on improving several indicators of liver function in patients with CLD and liver cirrhosis. However, unlike the results of our previous clinical study, the smaller incremental changes in liver function in patients with CLD who received eltrombopag for 6 mo were due to patient selection from a heterogeneous population. We highlight the current knowledge concerning the role of platelets in CLD and cancer and anticipate a novel application of platelet-based clinical therapies to treat liver disease.

Spotlight on romiplostim in the treatment of children with chronic immune thrombocytopenia: design, development, and potential place in therapy.

Primary immune thrombocytopenia (ITP) is an autoimmune disorder characterized by isolated thrombocytopenia. In approximately one-third of cases, the duration of thrombocytopenia will extend beyond 12 months consistent with a diagnosis of chronic ITP. Minor bleeding manifestations are common in chronic ITP while severe or life-threatening bleeding complications are uncommon. Moreover, spontaneous resolution occurs in the majority of children with chronic ITP necessitating treatment in only those children with ongoing bleeding manifestations or impairment in health-related quality of life (HRQOL). The characterization of thrombopoietin (TPO) and remarkable advancements in our understanding of the pathophysiology of ITP has led to the development of a new class of agents, the TPO-receptor agonists that have documented efficacy in the amelioration of thrombocytopenia and bleeding manifestations in chronic ITP. Romiplostim is a second-generation TPO-receptor agonist that has undergone limited evaluation in the treatment of chronic ITP in children. Evolving data suggest that romiplostim may be a safe and effective agent in the treatment of chronic ITP in children. Additional data are needed to confirm its ability to increase platelet counts, decrease bleeding manifestation, and improve the HRQOL of children and caregivers impacted by chronic ITP.

Apreciación crítica del estudio "efectividad y seguridad de romiplostim comparado con eltrombopag para el tratamiento de pacientes con púrpura trombocitopénica inmune que fallaron a otros tratamientos previos" / Critical appraisal of the study "effectiveness and safety of romiplostim compared to eltrombopag for the treatment of patients with immune thrombocytopenic purpura who failed other previous treatments"

INTRODUCCIÓN: La trombocitopenia idiopática (TIP) o púrpura trombocitopénica inmunológica o autoinmune, es un trastorno hemorrágico crónico en el cual existe un aumento de la destrucción de plaquetas y reducción de su producción y supervivencia, llevando a complicaciones hemorrágicas de leves a severas que pueden causar incluso la muerte. El control de la TIP puede lograrse mediante un tratamiento secuencial que va desde el inicio con corticoesteroides, seguido de la esplenectomía, hasta el empleo de inmunosupresores y anticuerpos monoclonales en caso de no respuesta. En Colombia, eltrombopag (Revolade®) está indicado para el tratamiento de TIP crónica a fin de incrementar el recuento plaquetario y reducir o prevenir hemorragias en pacientes con respuesta insuficiente al tratamiento con corticoides o inmunoglobulinas, o que han presentado eventos adversos serios con estos. No obstante, AMGEN Biotecnológica S.A.S. ha nominado romiplostim (Nplate®) como medicamento susceptible de incluirse en el plan de beneficios, basado en evidencia favorable derivada de una evaluación indirecta de efectividad y seguridad de romiplostim comparado con eltrombopag para el tratamiento de TIP. OBJETIVO: Realizar una apreciación crítica del informe de "Efectividad y seguridad de romiplostim comparado con eltrombopag para el tratamiento de pacientes con púrpura trombocitopénica inmune que fallaron a otros tratamientos previos". METODOLOGÍA: Siguiendo la metodología propuesta por el Instituto de Evaluación Tecnológica en Salud (IETS), inicialmente se realizó una reunión con expertos clínicos y pacientes para exponer los resultados que presenta el informe de evaluación de efectividad y seguridad, a fin de discutir los desenlaces y comparadores utilizados y, eventualmente, identificar en consenso posibles omisiones por parte de los autores de la evaluación. Luego se realizó una réplica del protocolo de búsqueda en las diferentes bases de datos de donde se seleccionaron los artículos para el análisis. El objetivo de esta réplica era actualizar la búsqueda ejecutada por los autores de la evaluación, a fin de corroborar su correspondencia con los estudios reportados en el informe e identificar posibles estudios que hayan sido publicados en fecha posterior al periodo contemplado en la evaluación de efectividad y seguridad, y que aporten evidencia relevante. Finalmente se realizó una discusión amplia de los nuevos estudios identificados, así como de las conclusiones derivadas de la reunión con expertos, a fin de sintetizar la evidencia disponible sobre el tema, considerar las particularidades de la práctica clínica en Colombia. RESULTADOS: Pese a que los reportes sobre efectividad y seguridad de romiplostim y eltrombopag son escasos, y no se han realizado comparaciones directas entre ambos medicamentos, existen algunos estudios de buena calidad que demuestran su efectividad para el tratamiento de TIP en adultos. Así mismo, a nivel de seguridad, ambos medicamentos muestran un balance riesgo beneficio favorable. En la evaluación objeto de esta apreciación crítica se utiliza un método potente de comparación indirecta entre romiplostim y eltrombopag. La literatura revisada en dicha evaluación es de alta calidad, de modo que sus resultados se consideran robustos. Los resultados muestran mayor efectividad para romiplostim que para eltrombopag, con un perfil de seguridad relativamente idéntico para los dos medicamentos evaluados. Estos resultados no fueron refutados en el proceso de apreciación crítica. Tras la réplica actualizada del protocolo de búsqueda no se identificó nueva literatura con resultados contrarios a los presentados en el informe de evaluación original. De la reunión con expertos clínicos (hematólogos) y pacientes se determinó que los desenlaces y comparadores utilizados son adecuados y no omiten alternativas relevantes. No obstante, los expertos clínicos refieren que sus pacientes han tenido respuesta positiva al tratamiento de segunda línea tanto con eltrombopag como con romiplostim y que la elección de uno u otro medicamento no obedece a consideraciones de efectividad (pues, en su experiencia, ambas presentan efectividades similares), sino a consideraciones relacionadas con la zona de residencia del paciente y la facilidad de la vía de administración. CONCLUSIONES: Tanto romiplostim como eltrombopag son medicamentos eficaces para el tratamiento de segunda línea de TIP. Pese a que la evidencia disponible muestra una mejor respuesta plaquetaria global con romiplostim, no existe diferencia significativa en el sostenimiento de esta respuesta. Adicionalmente, en la elección de una u otra alternativa de tratamiento deben primar las características clínicas, sociales y preferencias específicas de cada paciente. Romiplostim puede ser más adecuado en pacientes tolerantes a la administración subcutánea y con fácil acceso a centros de salud con personal entrenado para la toma de pruebas de laboratorio previas a la aplicación, de modo que sea posible llevar estricto control del recuento plaquetario, efectos secundarios y características clínicas del paciente para decidir la continuidad o suspensión del medicamento. Eltrombopag, por su parte, por tratarse de un medicamento que se administra por vía oral es más recomendable en pacientes con tripanofobia o que residen en zonas rurales o cabeceras municipales pequeñas y que, por tanto, no tienen acceso a la supervisión de personal de salud entrenado. Se considera que la evaluación original es una evaluación de alta calidad y sus conclusiones son concordantes con lo encontrado en la revisión sistemática pero deben ser interpretadas con precaución, debido a que las mismas se basaron únicamente en los reportes de la literatura internacional y no se tuvo en cuenta el contexto del país, por ejemplo, no se tuvieron en cuenta las ventajas o desventajas inherentes a la vía de administración de los fármacos. Esta tecnología resultaría en una ampliación de las alternativas de tratamiento de TIP en el país, de modo que ello constituye una mejora en el espectro de opciones para los pacientes y, por tanto, se puede mejorar su calidad de vida.(AU)

Eficacia y seguridad de eltrombopag en pacientes con aplasia medular severa, no tributarios a terapia triple inmunosupresora ni trasplante de medula ósea / Efficacy and safety of eltrombopag in patients with severe medullary aplasia, non-tributary to immunosuppressive triple therapy and bone marrow transplantation

INTRODUCCIÓN: Antecedentes: El presente dictamen responde a la solicitud de evaluación de tecnología sanitaria del uso fuera del petitorio de Eltrombopag en pacientes con aplasia medular severa, no tributarios a terapia triple inmunosupresora ni trasplante de médula ósea. Aspectos Generales: La trombopeyetina es un factor humoral o citoquina, el cual estimula la producción de trombocitos (plaquetas), proliferación de megacariocitos de la médula ósea y por ende liberación de plaquetas en un mecanismo llamado trombopoyesis. El rol principal de las plaquetas es proveer la interacción y activación de factores de coagulación en la cascada de coagulación. Los pacientes con anemia aplásica exhiben altos niveles de trombopoyetina y pero aún así presentan trombocitopenia debido a una supresión o falla por parte de la producción de plaquetas en la médula ósea. Tecnología Sanitaria de Interés: Eltrombopag (ETP), Revolade o Promacta (GlaxoSmithKline lnc) es un medicamento agonista del receptor de la trombopoyetina (TPOr) que promueve la diferenciación megacariocítica, la proliferación y la producción de plaquetas. Es un agente hematopoyético que actúa como agonista no peptídico del receptor de la trombopoyetina. Interacciona con el dominio transmembrana e induce a la proliferación y diferenciación de los megacariocitos produciendo, a consecuencia de ello, un incremento en el recuento plaquetario. METODOLOGÍA: Estrategia de Búsqueda: Se llevó a cabo una búsqueda sistemática de la literatura con respecto a la eficacia y seguridad de Eltrombopag en pacientes con aplasia medular severa, no tributarios a terapia triple inmunosupresora ni trasplante de médula ósea. Para la búsqueda primaria se revisó en primer lugar la información disponible por entes reguladoras y normativas de autorización comercial como la Administración de Drogas y Alimentos (FDA) de Estados Unidos, la Agencia de Medicamentos Europea (EMA) y la Dirección General de Medicamentos y Drogas (DIGEMID) en el Perú. Seguidamente, se emplearon los motores de búsqueda de los metabuscadores Translating Research into Practice (TRIPDATABASE), Epistemonikos y Health Systems Evidence (HSE). Asimismo, se buscó información generada por grupos internacionales que realizan revisiones sistemáticas, evaluaciones de tecnologías sanitarias y guías de práctica clínica, tales como el National Institute for Health and Care Excellence (NICE) del Reino Unido, National Guideline Clearinghouse (NGC) de Estados Unidos, Canadian Agency for Drugs and Technologies in Health (CADTH) de Canadá, Scottish Medicines Consortium (SMC) de Escocia, Haute Authorité de Santé (HAS) de Francia, el Instituto de Evaluación de Tecnologías Sanitarias (IETS) de Colombia, el Instituto de efectividad clínica y sanitaria (IECS) de Argentina. Finalmente, se realizó una búsqueda dentro de las bases de datos Pubmed, EMBASE, y The Web of Science que a su vez fue complementada con una búsqueda en www.clinicaltrials.gov y www.clinicaltrialsregister.eu. RESULTADOS: Sinopsis de la Evidencia: De acuerdo con la pregunta PICO, se llevó a cabo una búsqueda de evidencia científica relacionada al uso de eficacia y seguridad de eltrombopag en pacientes con aplasia medular severa, no tributarios a terapia triple inmunosupresora ni trasplante de médula ósea. En la presente sinopsis se describe la evidencia encontrada a la fecha. Guías de práctica clínica: No se encontraron guías de práctica clínica de buena calidad que recomienden eltrombopag en AAS. Evaluaciones de tecnologías sanitarias: El grupo evaluador de NICE revisó este año (2016) la evidencia disponible para AAS con eltrombopag. Sin embargo es observable que tanto la CADTH de Canada, la SMC de Escocia, el IECS Argentina, IETS Colombia, y la HAS de Francia los cuales son referentes internacionales de evaluaciones de tecnologías sanitarias, no han realizado aún evaluaciones ni han emitido recomendaciones para el uso de eltrombopag en AAS. Ensayos clínicos: Se encontraron los ensayos clínicos fase II de Olnes et al., 2012 y Desmond et al., 2014. Ensayos clínicos no-publicados: Se encontraron tres estudios en progreso en la página de clinicaltrials.gov que corresponden a NCT01891994, NCT 01703169, y NCT 02148133. Otros documentos adicionales: Documento de recomendación como Guía de la BCSH. CONCLUSIONES: El presente dictamen responde a la solicitud de evaluación de tecnología sanitaria del uso fuera del petitorio de Eltrombopag en pacientes con aplasia medular severa, no tributarios a terapia triple inmunosupresora ni trasplante de médula ósea. Se encontraron dos ensayos clínicos fase II, no-aleatorizados, abiertos y de un solo brazo y tres ensayos clínicos en proceso no-publicados, los cuales evaluaron la respuesta hematológica a eltrombopag en la población de interés. La evidencia generada por éstos contiene limitaciones severas para la interpretación y generalización de los resultados para la población de interés. El Instituto de Evaluación de Tecnologías en Salud e Investigación ­IETSI, aprueba el uso de Eltrombopag en pacientes con aplasia medular severa, no tributarios a terapia triple inmunosupresora ni trasplante de médula ósea. La vigencia del presente dictamen preliminar es de un año. En los subsiguientes meses a la publicación del presente dictamen, se evaluará la nueva evidencia publicada en la literatura internacional, y se analizarán los datos clínicos de todos aquellos pacientes que hayan recibido eltrombopag en el contexto del presente dictamen, con el fin de establecer el impacto del mismo. Esta información será tomada en cuenta para actualizar el presente dictamen al culminar su vigencia.

How we manage immune thrombocytopenia in the elderly.

With prolonged life expectancy, immune thrombocytopenia (ITP) is frequent in elderly people. In this setting, ITP diagnosis is challenging because of the concern about an underlying myelodysplastic syndrome. Studies of older adults are lacking, and recommendations for treatment are based mainly on expert opinion. The therapeutic strategy differs from that for younger patients and must take into account the greater risk of bleeding and thrombosis, presence of comorbidities, possible impaired cognitive performance or poor life expectancy and concomitant medications, such as anticoagulant and antiplatelet therapy. Steroids and intravenous immunoglobulin (IVIg) therapy remain the first-line treatments in elderly patients, but prolonged treatment with steroids should be avoided and IVIg treatment may lead to renal failure. Splenectomy is less effective than in young patients and risk of thrombosis is increased. Severe co-morbidities can also contraindicate surgery. Therefore, other second-line treatments are frequently preferred. Danazol and dapsone can be an option for the less severe ITP form. Rituximab is a good option except in patients with a history of infection or with hypogammaglobulinaemia. Thrombopoietin agonists are attractive, especially for patients with severe comorbidities or with limited life expectancy but the risk of thrombosis is a concern.

Seguridad y eficacia del uso de eltrombopag en púrpura trombocitopénica inmune primaria que ha fracasado a la primera línea de tratamiento / Safety and efficacy of the use of eltrombopag in primary immune thrombocytopenic purpura that has failed to the first line of treatment

INTRODUCCIÓN: Antecedentes: El presente informe expone la evaluación de Eltrombopag en pacientes con diagnóstico de púrpura trombocitopénica inmune primaria que han fracasado a la primera línea de tratamiento. Aspectos Generales: La púrpura trombocitopénica inmune primaria o púrpura trombocitopénica idiopática (PTI) es una condición autoinmune usualmente benigna y de curso autolimitado caracterizada por el aumento de la destrucción plaquetaria y la sub-optima producción plaquetaria. Está definida como la presencia de plaquetas disminuidas, médula ósea normal y ausencia de otras causas de trombocitopenia. Tecnología Sanitaria de Interés: Eltrombopag: Eltrombopag (ETP), Revolade o Promacta (GlaxoSmithKline Inc), es un agente hematopoyético que actúa como agonista no peptídico del receptor de la trombopoyetina. Interacciona con el dominio transmembrana e induce a la proliferación y diferenciación de los megacariocitos produciendo, a consecuencia de ello, un incremento en el recuento plaquetario. Este medicamento se indica para el tratamiento de PTI. METODOLOGÍA: Estrategia de Búsqueda: Se realizó una búsqueda de la literatura con respecto a la eficacia y seguridad de ETP para el tratamiento de pacientes con PTI con fracaso a tratamiento de primera línea en las bases de datos de MEDLINE, EMBASE, CENTRAL, DARE y TRIPDATABASE. Se hizo una búsqueda adicional en www.clinicaltrials.gov, para poder identificar ensayos clínicos aún en elaboración o que no hayan sido publicados. Adicionalmente, se hizo una búsqueda dentro de la información generada por las principales instituciones internacionales hematológicas y agencias de tecnologías sanitarias que realizan revisiones sistemáticas (RS), evaluación de tecnologías sanitarias (ETS) y guías de práctica clínica (GPC). RESULTADOS: Se realizó la búsqueda bibliográfica y de evidencia científica que sustente el uso ETP para el tratamiento de pacientes con PTI con fracaso a tratamiento de primera línea según la pregunta PICO establecida. Para el presente documento se seleccionó el siguiente cuerpo de evidencia que es resumido a continuación: Guías Clínicas: Se identificaron dos GPC (una de Estados Unidos, una de España). Evaluaciones de tecnología sanitaria: Dos ETS (Reino Unido y Canadá). Revisiones sistemáticas: \r\nNo se identificaron RS de ECAs específicamente para ETP que responder nuestra pregunta PICO. Sin embargo se seleccionó una RS indirecta de ECAs que compara ETP con otro agonista del receptor de la trombopoyetina (romiplostim). Ensayos clínicos: Se identificador tres ECAs. Ensayos Clínicos registrados: \r\nSe encontró un ECA registrados uno contando con resultados preliminares. CONCLUSIONES: La púrpura trombocitopénica inmune primaria o púrpura trombocitopénica idiopática (PTI) es una condición autoinmune usualmente benigna y de curso auto-limitado caracterizada por el aumento de la destrucción plaquetaria y la sub-optima producción plaquetaria. Eltrombopag una droga que actúa como agonista no peptídico del receptor de la trombopoyetina por lo que se le considera de la familia de los agonistas de receptores de la trombopoyetina. Interacciona con el dominio transmembrana e induce a la proliferación y diferenciación de los megacariocitos produciendo un incremento en el recuento plaquetario. Las guías de práctica clínica recomiendan eltrombopag en indicaciones seleccionadas incluido el tratamiento después de un fracaso terapéutico de primera línea. Sin embargo no especifican una recomendación por sobre otra de las alternativas de tratamiento. En general, las recomendaciones sitúan a eltrombopag como una alternativa de tratamiento de segunda línea en pacientes con PTI, sin presentar una evidencia comparativa robusta con otras alternativas. Otras opciones de tratamiento generalmente mencionadas son esplenectomía, danazol (el cual se encuentra incluido en el Petitorio Farmacológico de Essalud) y rituximab. Las evaluaciones de tecnologías sanitarias son discordantes con respecto a su recomendación. La ETS que lo recomienda lo hace basado en un estudio de costo-efectividad y preferencias de pacientes con un descuento acordado con el fabricante. Mientras que la otra no la recomienda en ninguna indicación. Los ensayos clínicos que demuestran la seguridad y eficacia de eltrombopag en PTI en comparación al placebo son de buena calidad metodológica aunque con una muestra pequeña para ciertos subgrupos y evidentes conflictos de intereses \r\nde los autores. No existen estudios comparativos de eltrombopag con otros medicamentos o procedimiento para el manejo de pacientes con diagnóstico de PTI y falla de tratamiento de primera línea. Así, al momento, la evidencia clínica que apoya el uso de eltrombopag en púrpura trombocitopénica inmune primaria que ha fracasado a la primera línea de tratamiento es limitada, lo que se traduce en recomendaciones no consistentes en las guías de práctica clínica y evaluaciones de tecnología existentes. El Instituto de Evaluación de Tecnologías en Salud e Investigación- 'ETS' no autoriza el uso de eltrombopag en pacientes con púrpura trombocitopénica inmune primaria que ha fracasado a la primera línea de tratamiento.

Coloración anormal del suero asociado al tratamiento con eltrombopag, en paciente con trombopenia inmune / Abnormal coloring of serum associated to treatment with eltrombopag, in patients with immune thrombocytopenia

Se presenta un caso de trombopenia inmune tratado con eltrombopag en el que a las seis semanas se presentó una coloración rojiza en el suero del paciente que impedía la valoración analítica de su función hepática. Dicha coloración persistió hasta la supresión total del fármaco por falta de respuesta terapéutica Se describen experiencias similares en la literatura (AU)

A case of immune thrombocytopenia treated with eltrombopag is presented. At six weeks, the patient had reddish coloring in the serum that prevented analytic evaluation of the hepatic function. This coloring persisted until the total suppression of the drug due to lack of therapeutic response. Similar experiences have been described in the literature (AU)

[Effectiveness of perioperative administration of eltrombopag in a patient with idiopathic thrombocytopenic purpura undergoing cardiovascular surgery].

We report a case of chronic aortic dissection and angina pectoris with idiopathic thrombocytopenic purpura treated perioperatively with eltrombopag. A 72-year-old man was admitted to our hospital because of significant enlargement of an ulcer-like projection in the thoracic aorta revealed by chest computed tomography after acute aortic dissection. Laboratory data showed thrombocytopenia with idiopathic thrombocytopenic purpura. Eltrombopag was administered 12.5 mg daily and increased by 12.5 mg every 2 weeks until 37.5 mg/day to control idiopathic thrombocytopenic purpura(ITP). After 7 weeks' eltrombopag therapy, thrombocyte increased, and the patient underwent total arch replacement. Nine months later, coronary angiography revealed progression of coronary artery stenosis at the left main trunk. The patient underwent off-pump coronary artery bypass grafting 10 days after initiation of eltrombopag therapy. His postoperative course was uneventful. Eltrombopag was suggested to be effective in perioperative management in a patient with idiopathic thrombocytopenic purpura undergoing cardiovascular surgery.

The biology of thrombopoietin and thrombopoietin receptor agonists.

Thrombopoietin (TPO) is the major physiological regulator of platelet production. TPO binds the TPO receptor, activates JAK and STAT pathways, thus stimulating megakaryocyte growth and platelet production. There is no "sensor" of the platelet count; rather TPO is produced in the liver at a constant rate and cleared by TPO receptors on platelets. TPO levels are inversely proportional to the rate of platelet production. Early recombinant TPO molecules were potent stimulators of platelet production and increased platelets in patients with immune thrombocytopenia, chemotherapy-induced thrombocytopenia, myelodysplastic syndromes and platelet apheresis donors. Neutralizing antibodies formed against one recombinant protein and ended their development. A second generation of TPO receptor agonists, romiplostim and eltrombopag, has been developed. Romiplostim is an IgG heavy chain into which four TPO agonist peptides have been inserted. Eltrombopag is an oral small molecule. These activate the TPO receptor by different mechanisms to increase megakaryocyte growth and platelet production. After administration of either to healthy volunteers, there is a delay of 5 days before the platelet count rises and subsequently reaches a peak after 12-14 days. Both have been highly effective in treating ITP and hepatitis C thrombocytopenia. Studies in a wide variety of other thrombocytopenic conditions are underway.

Pathogenesis and management of inherited thrombocytopenias: rationale for the use of thrombopoietin-receptor agonists.

Knowledge in the field of inherited thrombocytopenias (ITs) has considerably improved over the recent years. In the last 5 years, nine new genes whose mutations are responsible for thrombocytopenia have been identified, and this also led to the recognition of several novel nosographic entities, such as thrombocytopenias deriving from mutations in CYCS, TUBB1, FLNA, ITGA2B/ITGB3, ANKRD26 and ACTN1. The identification of novel molecular alterations causing thrombocytopenia together with improvement of methodologies to study megakaryopoiesis led to considerable advances in understanding pathophysiology of ITs, thus providing the background for proposing new treatments. Thrombopoietin-receptor agonists (TPO-RAs) represent an appealing therapeutic hypothesis for ITs and have been tested in a limited number of patients. In this review, we provide an updated description of pathogenetic mechanisms of thrombocytopenia in the different forms of ITs and recapitulate the current management of these disorders. Moreover, we report the available clinical and preclinical data about the role of TPO-RAs in ITs and discuss the rationale for the use of these molecules in view of pathogenesis of the different forms of thrombocytopenia of genetic origin.

Pathophysiology and management of primary immune thrombocytopenia.

Primary immune thrombocytopenia, or idiopathic thrombocytopenic purpura (ITP), is an autoimmune disorder characterized by isolated thrombocytopenia due to accelerated platelet destruction and impaired platelet production. Autoantibodies against platelet surface glycoproteins, such as GPIIb/IIIa and GPIb/IX complexes, play major roles in both platelet destruction and impaired platelet production, although autoantibody-independent mechanisms, such as T cell-mediated cytotoxicity, may also be involved in its pathogenesis. Recent advances in the localization of autoantigenic epitopes and the characterization of T cell functional abnormalities in ITP patients have improved our understanding of the pathophysiology of this disease. Although corticosteroids and splenectomy remain central to the treatment of ITP, a new class of drugs, i.e., thrombopoietin receptor agonists (TPO-RAs) and rituximab, have substantially broadened the therapeutic options for refractory ITP patients. Moreover, the success of TPO-RAs in ITP patients shows that reduced platelet production caused by impaired megakaryocytopoiesis plays a greater role in ITP than previously recognized.

Pathophysiology and management of thrombocytopenia in bone marrow failure: possible clinical applications of TPO receptor agonists in aplastic anemia and myelodysplastic syndromes.

Aplastic anemia is a bone marrow failure syndrome that causes pancytopenia and can lead to life-threatening complications. Bone marrow transplantation remains the standard of care for younger patients and those with a good performance status but many patients may not have a suitable donor. Immunosuppressive therapy is able to resolve cytopenias in a majority of patients with aplastic anemia but relapses are not uncommon and some patients remain refractory to this approach. Patients may require frequent blood and platelet transfusion support which is expensive and inconvenient. Life-threatening bleeding complications still occur despite prophylactic platelet transfusion. Thrombopoietin (TPO) mimetics, such as romiplostim and eltrombopag, were developed to treat patients with refractory immune thrombocytopenia but are now being investigated for the treatment of bone marrow failure syndromes. TPO is the main regulator for platelet production and its receptor (c-Mpl) is present on megakaryocytes and hematopoietic stem cells. Trilineage hematopoietic responses were observed in a recent clinical trial using eltrombopag in patients with severe aplastic anemia refractory to immunosuppression suggesting that these agents can provide a new therapeutic option for enhancing blood production. In this review, we discuss these recent results and ongoing investigation of TPO mimetics for aplastic anemia and other bone marrow failure states like myelodysplastic syndromes. Clonal evolution or progression to acute myeloid leukemia remains a concern when using these drugs in bone marrow failure and patients should only be treated in the setting of a clinical trial.

Selecting agonists from single cells infected with combinatorial antibody libraries.

We describe a system for direct selection of antibodies that are receptor agonists. Combinatorial antibody libraries in lentiviruses are used to infect eukaryotic cells that contain a fluorescent reporter system coupled to the receptor for which receptor agonist antibodies are sought. In this embodiment of the method, very large numbers of candidate antibodies expressing lentivirus and eukaryotic reporter cells are packaged together in a format where each is capable of replication, thereby forging a direct link between genotype and phenotype. Following infection, cells that fluoresce are sorted and the integrated genes encoding the agonist antibodies recovered. We validated the system by illustrating its ability to generate rapidly potent antibody agonists that are complete thrombopoietin phenocopies. The system should be generalizable to any pathway where its activation can be linked to production of a selectable phenotype.