Safety and efficacy of romiplostim in children and adolescents with Immune thrombocytopenia: A systematic review

Abstract Objective To evaluate the efficacy and safety of romiplostim (thrombopoietin-receptor agonist) in the treatment of pediatric immune thrombocytopenia (ITP). Methods Searches were conducted in MEDLINE, EMBASE, LILACS, Cochrane Central Register of Controlled Trials and ClinicalTrials.gov (from January 2011 to August 2021). Randomized controlled trials (RCTs), double-blind, comparing romiplostim with a placebo in pediatric persistent or chronic ITP were included. The primary outcome was the overall response rate (platelets ≥ 50 × 109/L) in the absence of rescue therapy for at least two consecutive weeks. The secondary endpoints were the minimization of clinically significant bleeding and the necessity for rescue treatments and the maximization of safety (incidence of overall adverse events) and durable response (maintaining platelet counts for at least twelve weeks). Results Two double-blind randomized placebo-controlled trials (84 participants) were included in this systematic review. Our data showed that, compared to the placebo group, the proportion of patients achieving durable platelet response was significantly higher in the romiplostim group (p= 0.003, RR = 6.34, 95%CI = 1.89 - 21.23), as was the overall response in the romiplostim group (p= 0.002, RR = 3.62, 95%CI = 1.63 - 8.03). Significant bleeding incidents (p= 0.49), overall adverse events (p= 0.71) and the need for rescue treatment (p= 0.13) were not statistically different between the romiplostim and placebo groups. Conclusions Romiplostim might improve both durable and overall platelet response in children and adolescents with ITP, compared to a placebo. More clinical trials are needed to evaluate the efficacy and safety of romiplostim and to compare it with other second-line treatments that are being used in pediatric ITP.

Ampliação de uso do eltrombopague para o tratamento adicional a imunossupressor em pacientes adultos com anemia aplástica grave / Expansion of use of eltrombopague for the Additional immunosuppressive treatment in adult patients with severe aplastic anemia

INTRODUÇÃO: A anemia aplástica (AA) é uma doença rara e com risco de vida devido à falha herdada ou adquirida da medula óssea para produzir células sanguíneas, levando à pancitopenia progressiva. O tratamento para AA é determinado por uma série de fatores, incluindo gravidade da pancitopenia, idade do paciente, disponibilidade de doadores de célulastronco hematopoética, fonte de célula-tronco hematopoética, disponibilidade de imunossupressão e acesso a terapias ideais. Eltrombopague, um agonista de trombopoietina (TPO) vem emergindo como uma opção de tratamento para AA grave associado a terapia imunossupressora padrão. INDICAÇÃO: Pacientes adultos com anemia aplástica grave. PERGUNTA: Eltrombopague associado à terapia imunossupressora padrão (imunoglobulina antitimócito [ATG] e ciclosporina) é eficaz, seguro e custo-efetivo no tratamento de pacientes adultos com AA grave, quando comparado à terapia imunossupressora padrão (ATG e ciclosporina) isolada no SUS? EVIDÊNCIAS CLÍNICAS: A partir de uma busca bibliográfica conduzida nas bases PubMed, EMBASE e Cochrane Reviews, um ensaio clínico randomizado (ECR) foi selecionado, fornecendo evidências sobre a eficácia e segurança do eltrombopague adicionado ao tratamento imunossupressor em pacientes adultos com AA grave. Os pacientes apresentaram uma resposta completa em três meses de 10% no Grupo A (controle) e 22% no Grupo B (intervenção) (OR: 3,2; IC 95%, 1,3 a 7,8; P=0,01). Aos seis meses, a taxa de resposta geral foi de 41% no Grupo A e 68% no Grupo B. Os tempos médios para a primeira resposta foram de 8,8 meses (Grupo A) e 3,0 meses (Grupo B). A adição de eltrombopague à terapia imunossupressora padrão não resultou em melhora significativa da sobrevida global. A taxa de sobrevida global em dois anos foi de 85% (IC95%:78 a 92) para o grupo controle e de 90% (IC95%: 82 a 97) para o grupo intervenção. No entanto, o eltrombopague adicionado à terapia imunossupressora padrão aumentou a sobrevida livre de eventos de 34% para 46% em dois anos por meio da redução da refratariedade inicial à imunossupressão. A incidência de eventos adversos graves foi semelhante nos dois grupos. Para os desfechos resposta hematológica, sobrevida global, sobrevida livre de eventos, qualidade de vida e eventos adversos, considerou-se moderada qualidade de evidência pelo GRADE. AVALIAÇÃO ECONÔMICA: Na análise de custo-efetividade, empregando árvore de decisão e considerando-se o desfecho Taxa de Resposta Global, comparou-se o tratamento padrão (TP) versus a adição de eltrombopague ao TP, em um horizonte temporal de um ano. Ao demonstrar menor custo e maior efetividade, eltrombopague + TP se mostrou custo-efetiva no tratamento da AAG em pacientes não elegíveis ao TCTH, considerando-se a RCEI de - R$ 287.140,99. Na análise de sensibilidade, variando-se os custos de ATG e de eltrombopague, os resultados mostraram-se estáveis nos cenários avaliados, continuando a demonstrar que a adição de eltrombopague ao TP é custo-efetiva. ANÁLISE DE IMPACTO ORÇAMENTÁRIO: Avaliando-se três cenários diferentes em cinco anos, e considerando uma abordagem epidemiológica e demanda aferida (dispensações de ciclosporina para AA no SUS), a ampliação de uso do eltrombopague pode gerar economia de recursos de até R$ 241,2 milhões, ou seja, 12% menor do que o valor gasto no cenário de referência. Entretanto, nos cenários que se pressupõe menor uso do eltrombopague, a economia de recursos é menor. No cenário 2 o impacto orçamentário incremental é de - R$ 188,59 milhões e no cenário 3 é de - R$ 134 milhões. MONITORAMENTO DO HORIZONTE TECNOLÓGICO: Foi detectada uma tecnologia para compor o tratamento adicional a imunossupressor em pacientes adultos com AAG. Trata-se do hetrombopag, um agonista do receptor de trombopoetina, mesmo mecanismo de ação da tecnologia em avaliação neste relatório, encontrando-se em fase 3 de pesquisa clínica, e sem registro para qualquer indicação na Anvisa, FDA ou EMA. CONSIDERAÇÕES FINAIS: A AA é uma doença rara e frequentemente grave ou muito grave e que até o momento, não dispunha de um tratamento clínico com resultados satisfatórios, cenário esse que perdura por mais de 30 anos. No presente relatório, é apresentado um ECR multicêntrico, com moderada qualidade de evidência, recentemente publicado e com um número expressivo de pacientes, considerando-se a raridade da doença e que trouxe resultados significativamente superiores, quando comparado ao tratamento padrão isolado em praticamente todos os desfechos avaliados, além de perfil de seguração comparável ao tratamento atual. Na avaliação econômica, a adição de eltrombopague ao tratamento padrão trouxe vantagens clínicas e econômicas, mostrando ser custo-efetiva. Assim também, na análise de impacto orçamentário, a ampliação de seu uso, considerando-se que a tecnologia já está incorporada no SUS para o tratamento de TPI, trouxe economia de recursos em todos os cenários avaliados. RECOMENDAÇÃO PRELIMINAR DA CONITEC: No dia 09 de março de 2022, em sua 106ª Reunião Ordinária, os membros da Conitec deliberaram que a matéria fosse disponibilizada em consulta pública com recomendação preliminar favorável à ampliação de uso do eltrombopague para o tratamento adicional a imunossupressor em pacientes adultos com anemia aplástica grave. Considerou-se que as evidências apresentadas demonstraram eficácia e segurança acerca do tratamento proposto frente às alternativas terapêuticas já disponíveis no SUS, além de ser custo-efetivo e apresentar economia de recursos para o SUS. CONSULTA PÚBLICA: Foi realizada no período de 04/04/2022 a 25/04/2022. Foram recebidas 51 contribuições, sendo 21 pelo formulário técnico-científico e 30 pelo formulário sobre experiência ou opinião. Todas as contribuições recebidas concordaram com a recomendação preliminar da Conitec, sendo favoráveis à ampliação de uso da tecnologia. Assim, o entendimento da Conitec não foi alterado. RECOMENDAÇÃO FINAL DA CONITEC: Diante do exposto, os membros do Plenário da Conitec, em sua 108ª Reunião Ordinária, no dia 05 de maio de 2022, deliberaram por unanimidade recomendar a ampliação de uso do eltrombopague para o tratamento adicional a imunossupressor em pacientes adultos com anemia aplástica grave. Por fim, foi assinado o Registro de Deliberação nº 728/2022. DECISÃO: Ampliar o uso do eltrombopague para o tratamento adicional a imunossupressor em pacientes adultos com anemia aplástica grave, no âmbito do Sistema Único de Saúde - SUS conforme a Portaria nº 47, publicada no Diário Oficial da União nº 105, seção 1, página 78, em 3 de junho de 2022.

Research Status of TPO/c-MPL Signaling Pathway in Acute Myeloid Leukemia--Review / 中国实验血液学杂志

Thrombopoietin (TPO) can activate hematopoietic cell proliferation by its receptor c-MPL mediated downstream pathways and induce the generation of megakaryocyte. In recent years, domestic and foreign researches have confirmed that TPO/ c-MPL pathway also plays an important role in the self-renewal and quiescence of leukemia stem cell, and its expression in acute myeloid leukemia (AML) also indicates the chemotherapy resistance and poor prognosis. In this article, the research progress of the roles of TPO/c-MPL pathway in chemotherapy resistance, prognosis of AML patients, and the application of TPO/ c-MPL receptor agonists in AML were summarized briefly.

Clinical Characteristics and Bone Marrow Histopathology Features in Essential Thrombocythaemia Patients with Different Gene Mutation in China / 中国实验血液学杂志

OBJECTIVE@#To investigate the clinical characteristics, laboratorial and bone marrow pathological features of primary thrombocytopenia (ET) patients with different mutations of CALR, JAK2 and MPL genes.@*METHODS@#The chinical data of 120 cases of ET in Jiangsu provincial people's hospital/ The First Affiliated Hospital of Nanjing Medical University from January 2015 to December 2017 were collected and analyzed, including 76 cases with JAK2 gene mutation, 40 cases with CALR gene mutation, 2 cases with MPL gene mutations, 2 cases without gene mutation.@*RESULTS@#Among the ET patients, compared with the JAK2 gene mutation, CALR gene mutation showed statistically significant deareament of white blood cells and hemoglobin (P=0.001, P=0.01) and the male platelets in CALR group showed significant increament (P=0.04). Fourthermore, the average number of megakaryocytes and its cluster numbers in each hight power field of vision showed statistically significant decreament in CALR group as compared with JAK2 group (P=0.001, P=0.001), and thrombotic events in CALR group were signicantly lower than those in JAK2 group (7.5% vs 18.4%) (P=0.03).@*CONCLUSION@#Mutations of CALR, JAK2 have different clinical characteristics and blood pathological changes of Chinese ET patients, and their clinical significance is worth to explore.

Agonistas del receptor de trombopoyetina (Eltrompopag) para la púrpura trombocitopénica idiopática crónica en adultos y niños / Thrombopoietin receptor agonists (Eltrompopag) for chronic idiopathic thrombocytopenic purpura in adults and children

TECNOLOGÍA EVALUADA: Eltrombopag. DESCRIPCION DE LA INTERVENCIÓN: Eltrombopag (Revolade, GlaxoSmithKline) aumenta la producción de plaquetas activando el receptor de trombopoyetina, estimulando así la producción de plaquetas y reduciendo el sangrado. Eltrombopag tiene una autorización de comercialización de ANMAT para tratamiento de 'púrpura trombocitopénica inmune crónica (idiopática) (PTI) en pacientes de 1 año o más que son refractarios a otros tratamientos (p. ej. corticosteroides, inmunoglobulinas y esplenectomía). BUSQUEDA BIBLIOGRÁFICA: Se realizaron búsquedas en MEDLINE (desde 1950 hasta marzo de 2011), EMBASE (desde 1974 hasta marzo de 2019), y en el Registro Cochrane Central de Ensayos Controlados (Cochrane Central Register of Controlled Trials, CENTRAL) (Cochrane Library 2011, Número 3), para identificar todos los metaanálisis y ensayos con asignación aleatoria sobre la PTI crónica. RESULTADOS: Se incluyeron seis ensayos con 808 pacientes. Cinco estudios compararon los agonistas de receptores de TPO con placebo (romiplostim: 100, eltrombopag: 299, placebo: 175); un estudio comparó los agonistas de receptores de TPO con la atención estándar (AE) (romiplostim: 157; AE: 77). La AE incluyó una variedad de tratamientos, como glucocorticoide, inmunoglobulina anti-D, inmunoglobulina intravenosa, rituximab, azatioprina, etcétera. La supervivencia general, una de nuestras medidas de resultado primarias, no fue estudiada por estos ECAs y no fue posible calcular el número necesario a tratar (NNT). Otra medida de resultado primaria, la mejoría en los eventos de hemorragia significativa, no reveló ninguna diferencia significativa entre el grupo de agonistas de receptores de TPO y el grupo de control (placebo o AE) (versus cociente de riesgos [CR] del placebo 0,48, intervalo de confianza [IC] del 95%: 0,20 a 1,15; versus CR de la AE 0,49, IC del 95%: 0,15 a 1,63). En cuanto a las medidas de resultado secundarias, los agonistas de receptores de TPO mejoraron de forma estadísticamente significativa la respuesta plaquetaria general (versus CR del placebo 4,06, IC del 95%: 2,93 a 5,63; versus CR de la AE 1,81, IC del 95%: 1,37 a 2,37), la respuesta completa (versus CR del placebo 9,29; IC del 95%: 2,32 a 37,15) y la respuesta duradera (versus CR del placebo 14,16; IC del 95%: 2,91 a 69,01). Hubo una reducción significativa en los eventos de hemorragia general (grado 1 a 4 de la OMS) en comparación con el placebo (CR 0,78; IC del 95%: 0,68 a 0,89), pero no en comparación con la AE (CR 0,97; IC del 95%: 0,75 a 1,26). EXPLICACIONES: Funded by drug company. There is evidence that industry-sponsored trials may overestimatethetreatmenteffect(Bhandari 2004). Los intervalos de confianza son amplios e incluyen no efecto. Estudio que evaluó intervención con Romiplostin.

Detection of Genetic Mutations in Primary Hypereosinophilia Patients / 中国实验血液学杂志

OBJECTIVE@#To explore the potential pathogenetic mutations of primary hypereosinophilia（HEN）by sequencing FGFR1 FLT3, MPL and JAK2 genes, and to clarify their effect on clinical manifestation and prognosis of HEN patients.@*METHODS@#The direct DNA sequencing was employed to detect the gene mutations of FGFR1, FLT3, MPL and JAK2 in HEN patients.@*RESULTS@#One deletion mutation (2654_2753del) within tyrosine kinase domain of FLT3 gene was found in a patient suffered from severe symptoms and ended with dismal outcome, which induced a premature stop codon (G885fsX888). For FGFR1, a new variation described as 1014_1019del AACAGT for nucleotide change was found in 19 cases, resulting in T339_V340del at the protein level.@*CONCLUSION@#The deletion of 6 bases in the FGFR1 gene (1014_1019del AACAGT) is first reported as non-synonymous SNP (nsSNP) site in the patients with primary hypereosinophilia. Deletion mutations in the FLT3 gene may be related with malignant clinical features and poor prognosis.

Consensus on clinical diagnosis, treatment and prevention management of chemotherapy induced thrombocytopenia in China(2018) / 中华肿瘤杂志

Chemotherapy induced thrombocytopenia (CIT) is a common side-effect of chemotherapy in cancer patients, which lead to dose and cycle reduction or chemotherapy delay, or even the need of platelet transfusion. Therefore, CIT significantly increases the cost of treatment, reduces the efficacy of chemotherapy and the quality of life, and shortens the survival time of patients. The main treatments of CIT include transfusion of platelets, recombinant human thrombopoietin (rhTPO), and recombinant human interleukin-11 (rhIL-11). RhIL-11 is the first approved thrombocytopoietic cytokine. Interleukin-11 has been shown to be effective in the treatment of thrombocytopenia. RhTPO is a recombinant full-length glycosylated thrombopoietin, which is a ligand for c-Mpl protein. Several observations indicated that administration of rhTPO before and after chemotherapy might be beneficial to patients, which enhances platelet recovery and reduces thrombocytopenia after moderately myelosuppressive regimens. In recent years, the application of rhTPO in CIT treatment has dramatically changed the management and treatment plan of CIT. The China Society of Clinical Oncology (CSCO) published a consensus on CIT in 2014. Based on this, the expert committee updated "Consensus on clinical diagnosis, treatment and prevention management of chemotherapy induced thrombocytopenia in China (2018)" according to the recent literature and clinical research. The new evidence-based practice consensus for CIT aims to provide more reasonable diagnosis, treatment of prevention regimens for CIT patients to maintain the normal platelet counts.

Mutation Rate and Clinical Characteristics of CALR, JAK2 V617F and MPL W515K Genes in Patients With Primary Thrombocythemia / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To analyze the mutation rate and clinical characteristics of CALR, MPL W515K and JAK2 V617F genes in patients with primary thrombocythemia (PT).</p><p><b>METHODS</b>Fifty-six patients with PT were selected as the research objects in our hospital. The CALR and MPL W515K gene mutations were determined by genomic DNA-PCR direct sequencing of the PCR products, and the JAK2 V617F gene mutation was detected by allele specific PCR method.</p><p><b>RESULTS</b>Among the 56 patients with PT there were 14 cases of CALR gene mutation with the incidence rate of 25%, including 6 cases of type I, 5 cases of type II and 3 cases of type III. The sex, age, platelet(Plt) count, white blood cell (WBC) count and hemoglobin (Hb) level in the type I case of CALR gene mutation all were not significantly different from that in type II and III(all P>0.05); the WBC level in type III group significantly increased in comparison of type II group (P<0.05), while the sex, age, Hb and Plt levels showed no significant difference between the type III and type II groups (P>0.05). There were 3 cases of MPL W515K gene mutation with the incidence rate of 5.36%; 21 cases of JAK2 V617F gene mutation with the incidence rate of 37.50%. There were 13 cases of CALR gene mutation in negative patients with MPL W515K and JAK2 V617F (18 cases) with 72.22% incidence rate (13/18), and there was no cases of 1 or 2 gene mutations coexisted. The levels of Hb and WBC in peripheral blood of patients with CALR mutation were significantly lower than those of JAK2 V617F mutation (both P<0.05). In 56 cases, there were 3 cases of abnormal karyotype, with the incidence rate of 5.36%. The mutation rate of CALR gene in abnormal karyotypes (66.67%) was significantly higher than that of normal karyotypes (20.75%) (P<0.01).</p><p><b>CONCLUSION</b>The incidence of JAK2 V617F gene mutation increases in the patients with primary thrombocythemia; CALR mutation rate is higher in the patients with negative MPL W515K and JAK2 V617F gene mutation, which may closely correlate with abnormal karyotype; the levels of peripheral Hb and WBC in PT the patients with CALR gene mutation are significantly lower than those in patients with JAK2 V617F mutation.</p>

Detection and Diagnostic Values of JAK2, CALR, MPL Gene Mutations in 208 Cases of BCR/ABL1 Negative Chronic Myeloproliferative Diseases / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To detect the JAK2, CALR and MPL gene mutations in patients with BCR/ABL1 negative chronic myeloproliferative diseases（BCR/ABL1-CMPD）and to evaluate their diagnostic value.</p><p><b>METHODS</b>Two hundred and eight cases of BCR/ABL1-CMPD comprising of 146 cases of essential thrombocythemia（ET）, 37 cases of polycythemia vera（PV）and 25 cases of primary myelofibrosis（PMF）from March 2012 to December 2015 were enrolled in the BCR/ABL1-CMPD, while 124 cases of secondary thrombocythemia and 73 cases of secondary polycythemia were enrolled in the control group. The genomic DNA and total RNA Were isolated from bone marrow or peripheral blood, then the exons 12 to 20 of JAK2 gene, exon 10 of MPL gene and exons 3 to 9 of CALR gene were analyzed by using DNA sequencing.</p><p><b>RESULTS</b>among 146 ET patients, the JAK2, CALR or MPL mutations were found in: 138 cases（94.5%）including 86 cases with JAK2V617F mutation（58.9%）and 2 cases（1.4%）with exon 12 of JAK2 mutations. CALR mutations were detected in 41 cases（28.1%）, among them type 1（c.1092_1143del）in 22 cases, type 2（c.1154_1155insTTGTC）in 11 cases, and type 5（c. 1091_1142del）, type 8（c.1104_1137del）, type 41(c.1107_1137del）, type 42(c.1125_1125del）in one case respectively. In addition, 4 cases were detected withother mutations of the CALR gene（c.1107_1115del, c.1111_1144 del, c.1101 A>C, c.1112_1117del）. Moreover, 9 cases harbored MPL mutations（6.2%）. Secondly, 31 patients were detected with JAK2V617F mutation（83.8%）in 37 cases of PV, and JAK2 exon 12 mutations were found in 2 cases（5.4%）. Besides, CALR mutations were detected in 2 cases（5.4%）, including 1 case of type I, the other of novel mutation of CALR. Thirdly, 19 in 25 cases of PMF were detected with JAK2V617F mutation（76%）, 2 cases with CALR mutations（8%）. 4 patients（16%）, JAK2, CALR or MPL mutations were not detected, but among them 3 cases were found harboring other genetic abnormalities. Fourthly, no mutations of JAK2, MPL and CALR genes were detected in 124 patients with secondary thrombocytosis and 73 cases with secondary polycythemia.</p><p><b>CONCLUSION</b>Combined detection of JAK2, CALR and MPL gene mutations can cover the vast majority of patients with BCR/ABL1-negative myeloproliferative neoplasms. For higher frequencies of the mutations of CALR in ET patients, CALR mutation can be used as a new diagnostic marker in ET patients with JAK2 and MPL wild type.</p>

Clinical Characteristic of "triple-negative" Essential Thrombocythaemia Patients and Mutation Analysis by Targeted Sequencing / 中国实验血液学杂志

<p><b>BACKGROUND</b>Essential thrombocythemia is a subgroup of myeloproliferative neoplasms. Previous studies identified mutations of JAK2, CALR, and MPL that are closely related with the pathogenesis of myeloproliferative neoplasms. All these mutations contribute to the hyperactivation of JAK2/STAT pathway. However, a small proportion of essential thrombocythemia patients does not display such mutations. The pathogenesis of "triple-negative" form of essential thrombocythemia remains unknown.</p><p><b>OBJECTIVE</b>To investigate the clinical characteristics of triple-negative essential thrombocythemia and related mutation genes.</p><p><b>METHODS</b>To identify the mutations associated with triple-negative essential thrombocythemia, next-generation sequencing was used to conduct targeted sequencing of 360 genes in samples from 68 patients.</p><p><b>RESULTS</b>At least one missense mutation was detected in all the patients and all the detected genes. After screening the data, it was observed that 10 genes with the 10 highest mutation were follows: FLT3, SH2B3, ASXL1, ADAMTS1, TET2, TP53, EGFR, CUX1, GATA2, and MPL.When only rare genes (i.e., with a frequency in Asian populations lower than 5%, as estimated by the 1000 Genomes Project) were analyzed, the most frequently mutated genes in the patients were TET2 (33.82%), SH2B3(29.41%), and ASXL1 (23.53%). Our study identified some mutations that did not previously reported. Although all these mutations need further validation, high incidence rates may indicate relevance of the respective mutations to essential thrombocythemia pathogenesis. Some of the detected mutations have been previously reported; these mutations were also found in a large proportion of our subjects.</p><p><b>CONCLUSION</b>whole-exon sequencing can provide a higher level of accuracy for gene mutation analysis and assist in identifying mutations that contribute to illustrate the pathogenesis of essential thrombocythemia.</p>

Differences in Hematological and Clinical Features Between Essential Thrombocythemia Cases With JAK2- or CALR-Mutations

No abstract available.

Clinical Manifestation of Calreticulin Gene Mutations in Essential Thrombocythemia without Janus Kinase 2 and MPL Mutations: A Chinese Cohort Clinical Study / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Recently, calreticulin (CALR) gene mutations have been identified in patients with essential thrombocythemia (ET). A high-frequency of ET cases without Janus kinase 2 (JAK2) mutations contain CALR mutations and exhibit clinical characteristics different from those with mutant JAK2. Thus, we investigated the frequency and clinical features of Chinese patients of Han ethnicity with CALR mutations in ET.</p><p><b>METHODS</b>We recruited 310 Chinese patients of Han ethnicity with ET to analyze states of CALR, JAK2V617F, and MPLW515 mutations by polymerase chain reaction and direct sequencing. We analyzed the relationship between the mutations and clinical features.</p><p><b>RESULTS</b>CALR, JAK2V617F, and MPLW515 mutations were detected in 30% (n = 92), 48% (n = 149), and 1% (n = 4) of patients with ET, respectively. The mutation types of CALR involved deletion and insertion of base pairs. Most of them were Type 1 (52-bp deletion) and Type 2 (5-bp insertion, TTGTC) mutations, leading to del367fs46 and ins385fs47, respectively. The three mutations were exclusive. Clinically, patients with mutated CALR had a lower hemoglobin level, lower white blood cell (WBC) count, and higher platelet count compared to those with mutated JAK2 (P < 0.05). Furthermore, a significant difference was found in WBCs between wild-type patients (triple negative for JAK2, MPL, and CALR mutations) and patients with JAK2 mutations. Patients with CALR mutations predominantly clustered into low or intermediate groups according to the International Prognostic Score of thrombosis for ET (P < 0.05).</p><p><b>CONCLUSIONS</b>CALR mutations were frequent in Chinese patients with ET, especially in those without JAK2 or MPL mutations. Compared with JAK2 mutant ET, CALR mutant ET showed a different clinical manifestation and an unfavorable prognosis. Thus, CALR is a potentially valuable diagnostic marker and therapeutic target in ET.</p>

Relationship between Calreticulin Gene Mutation and JAK2/MPL Negative Myeloproliferative Neoplasms / 中国实验血液学杂志

In 2008, WHO made the JAK2V617F gene mutation as one of the specific molecular diagnostic markers of BCR/ABL-negative myeloproliferative neoplasms (MPN). In 2013 two research teams demonstrated that whole genome sequencing technology (WGS) was used to detect calreticulin gene mutation in essential thrombocythaemia (ET) and primary myelofibrosis (PMF) patients with JAK2V617F⁻ and MPL⁻ mutations. In this review, the relationship of CALR gene mutation with MPN is briefly summarized.

Identification of a novel aberrant spliceosome of MPL gene (MPLL391-V392ins12)in patients with myeloproliferative neoplasms / 中华血液学杂志

<p><b>OBJECTIVE</b>To identify the MPL L391-V392ins12 spliceosome and analyze its frequencies in patients with myeloproliferative neoplasms (MPN).</p><p><b>METHODS</b>MPL aberrant spliceosome was identified through reverse transcription polymerase chain reaction (RT-PCR)combined with cloning sequencing. The mutation of this spliceosome in 248 MPN patients and 200 normal people was determined by allele-specific polymerase chain reaction (AS-PCR).</p><p><b>RESULTS</b>A novel aberrant spliceosome of MPL gene (MPL L391-V392ins12)was identified, i.e. 36 bp intron was retained between exon7 and exon8, and there were 12 amino acids (EGLKLLPADIPV)inserted. MPL L391-V392ins12 mutation was detected in 19 (7.66%)of the 248 patients with MPN, including 1 (1.92%) of 52 patients with PV, 14 (9.66%) of 145 with ET, and 4 (7.84%) of 51 with PMF. And the mutation was not detected in the group of 200 normal people.</p><p><b>CONCLUSION</b>MPL L391-V392ins12 spliceosome is an aberrant spliceosome present in the MPN. It can be detected in PV, ET and PMF, and more frequently in ET and PMF. This mutation may play an important role in the process of MPN.</p>

JAK2 V617F, MPL, and CALR Mutations in Korean Patients with Essential Thrombocythemia and Primary Myelofibrosis

Mutations in the calreticulin gene, CALR, have recently been discovered in subsets of patients with essential thrombocythemia (ET) or primary myelofibrosis (PMF). We investigated Korean patients with ET and PMF to determine the prevalence, and clinical and laboratory correlations of CALR/JAK2/MPL mutations. Among 84 ET patients, CALR mutations were detected in 23 (27.4%) and were associated with higher platelet counts (P=0.006) and lower leukocyte counts (P=0.035) than the JAK2 V617F mutation. Among 50 PMF patients, CALR mutations were detected in 11 (22.0%) and were also associated with higher platelet counts (P=0.035) and trended to a lower rate of cytogenetic abnormalities (P=0.059) than the JAK2 V617F mutation. By multivariate analysis, triple-negative status was associated with shorter overall survival (HR, 7.0; 95% CI, 1.6-31.1, P=0.01) and leukemia-free survival (HR, 6.3; 95% CI, 1.8-22.0, P=0.004) in patients with PMF. The type 1 mutation was the most common (61.1%) type among all patients with CALR mutations, and tended toward statistical predominance in PMF patients. All 3 mutations were mutually exclusive and were never detected in patients with other myeloid neoplasms showing thrombocytosis. CALR mutations characterize a distinct group of Korean ET and PMF patients. Triple-negative PMF patients in particular have an unfavorable prognosis, which supports the idea that triple-negative PMF is a molecularly high-risk disease.

Efficacy and safety of eltrombopag in adult refractory immune thrombocytopenia

BACKGROUND: Eltrombopag is a thrombopoietin receptor agonist with excellent treatment outcomes in immune thrombocytopenia (ITP). Here, we analyzed the dose of eltrombopag required to achieve and maintain safe platelet counts in Korean ITP patients. METHODS: Adult refractory ITP patients ( or =50,000 cells/microL). After achieving the target platelet count, the dose of concomitant ITP medications and eltrombopag was reduced to identify the lowest effective dose required to maintain the platelet count. RESULTS: Among 18 patients, 66.7% achieved complete response, 5.6% achieved platelet counts between 50,000 and 100,000 cells/microL, and 27.8% failed to achieve the target platelet count. The median ITP duration was significantly shorter in patients who achieved the target platelet count. The initial dose required to achieve the target platelet count was 25 mg/d. The adjusted maintenance doses were 25 mg twice per week or 25 mg/d. After discontinuation, 83.3% relapsed, and the median relapse-free survival was 15 days. Two relapsed and 1 failed patient switched to romiplostim. The response to romiplostim was similar to eltrombopag. During eltrombopag treatment, 38.9% showed hepatobiliary laboratory anomalies. Among 9 follow-up bone marrow examinations, 1 revealed fibrosis after 1 year of treatment. CONCLUSION: Eltrombopag was well tolerated with excellent treatment outcomes in refractory adult ITP patients. Low-dose eltrombopag effectively maintained the target platelet count. However, some patients required longer or higher-dose treatment to maintain the target platelet count, especially in heavily pretreated or longer ITP cases.

Calreticulin Exon 9 Mutations in Myeloproliferative Neoplasms

BACKGROUND: Calreticulin (CALR) mutations were recently discovered in patients with myeloproliferative neoplasms (MPNs). We studied the frequency and type of CALR mutations and their hematological characteristics. METHODS: A total of 168 MPN patients (36 polycythemia vera [PV], 114 essential thrombocythemia [ET], and 18 primary myelofibrosis [PMF] cases) were included in the study. CALR mutation was analyzed by the direct sequencing method. RESULTS: CALR mutations were detected in 21.9% of ET and 16.7% of PMF patients, which accounted for 58.5% and 33.3% of ET and PMF patients without Janus kinase 2 (JAK2) or myeloproliferative leukemia virus oncogenes (MPL) mutations, respectively. A total of five types of mutation were detected, among which, L367fs*46 (53.6%) and K385fs*47 (35.7%) were found to be the most common. ET patients with CALR mutation had lower leukocyte counts and ages compared with JAK2-mutated ET patients. CONCLUSION: Genotyping for CALR could be a useful diagnostic tool for JAK2-or MPL-negative ET or PMF patients. CALR mutation may be a distinct disease group, with different hematological characteristics than that of JAK2-positive patients.

Straightforward Identification of Masked Polycythemia Vera Based on Proposed Revision of World Health Organization Diagnostic Criteria for BCR-ABL1-Negative Myeloproliferative Neoplasms

No abstract available.

Congenital amegakaryocytic thrombocytopenic purpura [CAMT]

Congenital amegakaryocytic thrombocytopenia [CAMT] is a rare, autosomal recessive disorder induced by mutations of the gene coding for thrombopoietin [TPO] receptor [c-MPL] despite high levels of serum TPO. Patients initially present with isolated thrombocytopenia that subsequently progresses into pancytopenia. Although the mechanisms leading to aplasia are unknown, the age of onset has been reported to depend on the severity of the c-MPL functional defect. The primary treatment for CAMT is bone marrow transplantation. This report describes a newborn girl who presented to us with symptoms of sepsis but septic profile came negative except thrombocytopenia. Bone marrow biopsy was done for thrombocytopenia which revealed amegakaryocytic thrombocytopenia. She was given prednisolone.

Expression of c-MPL in leukemic stem cells from acute myeloid leukemia patients / 中国实验血液学杂志

This study was aimed to investigate the expression of c-MPL in acute myeloid leukemia (AML) and the correlation of the c-MPL expression with CD34 and CD38, so as to define the expression of c-MPL in leukemic stem cells. The expression levels of CD34, CD38 and c-MPL were detected by flow cytometry in bone marrow cells from 29 newly diagnosed AML patients. The relationship of c-MPL positive cell ratio with clinical parameters and correlation of c-MPL with CD34 and CD38 expression in AML patients were analyzed. The results showed that expression level of c-MPL in AML patients was significantly higher than that of normal controls (P < 0.05), and the expression level of c-MPL did not correlate with age, sex, white blood cell count, AML1-ETO fusion gene and remission after chemotherapy, but the expression of c-MPL in M2 and M5 patients was higher than that of normal control (P < 0.05). Expression of c-MPL in CD34 positive AML patients was obviously higher than that in CD34 negative AML patients (P < 0.01). c-MPL was significantly higher expressed in CD34(+) cells than that in CD34(-) cells (P < 0.001), while c-MPL expression was not significantly different between CD34(+)CD38(-) and CD34(+)CD38(-) cell groups. Positive correlation between c-MPL and CD34 expression was observed (r = 0.380, P = 0.042). It is concluded that expression of c-MPL is higher in AML patients, and positively correlates with the expression level of CD34. The c-MPL expresses in leukemic stem cells.