Eltrombopag increases platelet numbers in thrombocytopenic patients with HCV infection and cirrhosis, allowing for effective antiviral therapy

Application of thrombopoietic agents in cancer therapy-induced thrombocytopenia: A comprehensive review

Cancer therapy-induced thrombocytopenia (CT-IT) is one of the most common hematological toxicities of anti-cancer therapy, often leading to treatment dose reduced, postponed, or treatment plans altered or even discontinued. Thrombopoietin (TPO) is the only key regulatory factor in platelet production, and TPO receptor is considered an ideal target for the treatment of thrombocytopenia. Thrombopoietic agents, including recombinant human thrombopoietin (rhTPO) and thrombopoietin receptor agonists (TPO-RAs), bind to different regions of the TPO receptor, activating downstream signaling pathways to increase platelet levels. In recent years, numerous studies have demonstrated the effectiveness of thrombopoietic agents in the management of CT-IT. These agents can reduce bleeding risk, decrease platelet transfusions, and maintain relative dose intensity (RDI) of anti-cancer treatments. This article provides a review of the current progress in the application of thrombopoietic agents for CT-IT management.

Chinese expert consensus on clinical management of hepatopathy-related thrombocytopenia (2023 edition)

Hepatopathy-related thrombocytopenia refers to a reduction in platelet count caused by liver disease or its treatment. The incidence of this condition is correlated with the duration and severity of liver disease. The direct impact of thrombocytopenia on the clinical outcome of patients with liver disease is an increased risk of bleeding. In addition, the indirect effect involves delays or discontinuation of treatment due to the potential risk of bleeding. The pathophysiological mechanisms of hepatopathy-related thrombocytopenia include reduced platelet production, abnormal distribution, increased destruction or consumption, and so on. Current treatment strategies targeting different mechanisms include thrombopoietic agents, surgery, immunosuppressants, and platelet transfusion. However, their clinical application lacks standardization. The National Clinical Research Center for Infectious Diseases organized experts to discuss and develop this consensus to enhance the clinical management level of hepatopathy-related thrombocytopenia in China. The experts focused on aspects of diagnosis, classification, and choosing the best treatment plans based on the most recent research in the field.

Sequential Use of Romiplostim after Eltrombopag for Refractory Thrombocytopenia in Hydrocarbon-Induced Myelodysplasia

We describe the clinical course of a 65-year-old male patient who suffered from hydrocarbon-induced myelodysplasia and was successfully treated with the thrombopoietin receptor agonist (TPO-RA), romiplostim. Myelodysplastic syndromes (MDS) are characterized by ineffective hematopoiesis, cytopenias, and increased risk of leukemic transformation. Here, we present a clinical vignette of MDS-associated thrombocytopenia refractory to first-line drugs as well as the TPO-RA, eltrombopag. To date, romiplostim is an U.S. Food and Drug Administration (FDA)-approved drug for idiopathic thrombocytopenic purpura and thrombocytopenia secondary to liver disease. Of note, currently the FDA advises against its use in MDS based on previous long-term safety concerns. Since the therapeutic options for thrombocytopenia in MDS patients are sparse, repurposing and reassessing romiplostim in this setting have been the focus of recent studies. At the time of writing, no published double-blind randomized clinical trials have conducted a head-to-head comparison between romiplostim and eltrombopag in thrombocytopenic MDS patients. To the best of our knowledge, for a thrombocytopenic patient in the setting of MDS, this is the first documented report of refractory clinical response after a 2-year use of eltrombopag in which replacement of treatment with romiplostim resulted in sustained physiological counts of thrombocytes within four weeks.

Thrombopoietin Receptor Agonists in Post-Hematopoietic Cell Transplantation Complicated by Prolonged Thrombocytopenia: A Comprehensive Review

Hematopoietic cell transplantation (HCT) is a well-established procedure that has become a therapeutic mainstay for various hematological conditions. Prolonged thrombocytopenia following HCT is associated with a significant risk of morbidity and mortality, yet no universally recognized treatment protocol exists for such a complication. First-generation thrombopoietin receptor (TpoR) agonists as well as second-generation agents are known for their role in enhancing platelet production, and their use is expanding across various thrombocytopenic conditions. Therefore, we conducted this comprehensive review of the literature to provide an updated evaluation of the use of TpoR agonists and explore their efficacy and safety in the treatment of extended post-HCT thrombocytopenia. The literature search was conducted using PubMed database from 1996 through December 2023, using a predefined strategy with medical subject headings terms. We identified 64 reports on the utility of TpoR agonists, five of them were randomized controlled trials and the rest were retrospective observational studies and case series, with a total number of 1730 patients. Second-generation TpoR agonists appear more convenient than subcutaneous recombinant human thrombopoietin (rhTpo) as they can be orally administered and exhibit similar efficacy in platelet recovery, as indicated by recent trial results. Among these agents, avatrombopag, unlike eltrombopag, does not require any dietary restrictions, which could be more favorable for patients. However, eltrombopag remains the most extensively studied agent. TpoR agonists had promising effects in the treatment of post-HCT thrombocytopenia with a good safety profile so far, highlighting the potential benefit of their use.

Efficacy and Safety of Thrombopoietin Receptor Agonist (TPO-RA) in Patients with Chronic Liver Disease: A Systematic Review and Meta-Analysis

Context: The TPO-receptor agonist (TPO-RA) has been extensively studied for its use in thrombocytopenia. Objectives: We aimed to systematically analyze the efficacy and safety of TPO-RA in chronic liver disease patients. Methods: The study population consisted of adults with chronic liver disease. The intervention was TPO-RA. The primary outcome was the efficacy of TPO-RA (increase in thrombocyte levels and likelihood of avoiding thrombocyte transfusion pre-operatively), while the secondary outcome was the safety of TPO-RA. The demographics of the study and the usage of TPO-RA medications were used to classify the research. Results: This review consisted of 1529 chronic liver disease patients who received TPO-RA and 911 who received a comparator (placebo or thrombocyte transfusion). The TPO-RA significantly increased thrombocyte levels by 34.59 × 109/L (P < 0.00001). The use of TPO-RA pre-procedure reduced the likelihood of pre-operative platelet transfusion and up to seven days following the scheduled procedure by 88% (P < 0.00001). TPO-receptor agonist was not associated with all-cause mortality (P = 0.77) or an increase in thrombosis events, with a pooled OR of 1.36 (P = 0.43). According to a meta-regression analysis, the population may explain the heterogeneity. Subsequent leave-one-out sensitivity analysis of the thrombocyte level change after TPO-RA revealed that no single study was accountable for the heterogeneity of thrombocyte level changes. Conclusions: The use of TPO-RA increases the thrombocyte levels of chronic liver disease patients and reduces the odds of needing thrombocyte transfusion pre-operatively. TPO-receptor agonist is also safe to use, with no increase in mortality risk or thrombosis risk.

Avatrombopag as alternative therapy for severe aplastic anemia patients who are intolerant or unresponsive to eltrombopag

Introduction

Eltrombopag (EPAG), a thrombopoietin receptor agonist, was approved for the treatment of severe aplastic anemia (SAA) combined with immunosuppressive therapy (IST). However, EPAG contains a typical biphenyl structure, which causes liver function damage.

Methods

Twenty patients with SAA who were intolerant or refractory to EPAG were enrolled in a multicenter prospective registry of the Chinese Eastern Collaboration Group of Anemia (ChiCTR2100045895) from October 2020 to June 2023.

Results

Eight patients who were ineffective to EPAG, six with kidney impairment, and nine with abnormal liver function (two with concomitant liver and kidney impairment) were converted to avatrombopag (AVA) therapy with the median duration of AVA treatment was 6 (3-24) months. 17 cases (85%) achieved trilineage hematological response (HR): complete remission (CR) in 3 cases (15%), good partial remission (GPR) in 4 cases (20%), partial remission (PR) in 10 cases (50%), and no response (NR) in 3 cases (15%). The median time to response was 1.7 (0.5-6.9) months, with 16 cases (94%) achieving response within six months and 17 cases (100%) within 12 months. 9 cases (50%) achieved transfusion independence. AVA converted treatment was associated with higher neutrophil counts (0.8×109/L vs 2.2×109/L, p=0.0003), platelet counts (11×109/L vs 39×109/L, p=0.0008), hemoglobin count (59g/L vs 98g/L, p=0.0002), red cell count (1.06×1012/L vs 2.97×1012/L, p=0.001), and absolute reticulocyte count (31.99 ×109/L vs 67.05×109/L p=0.0004) were all significantly elevated compared with the pre-treatment level. After the conversion to AVA therapy, liver and kidney function indexes were maintained within the normal range, no AVA related grade 2 or higher adverse events occurred, and no thrombotic events occurred.

Conclusion

The conversion to AVA was an optimal choice for patients with SAA who were EPAG intolerant or refractory.

Clinical trial registration

http://www.chictr.org.cn/showproj.html?proj=125480, identifier ChiCTR2100045895.

Preoperative risk evaluation and optimization for patients with liver disease

The prevalence of liver disease is rising and more patients with liver disease are considered for surgery each year. Liver disease poses many potential complications to surgery; therefore, assessing perioperative risk and optimizing a patient's liver health is necessary to decrease perioperative risk. Multiple scoring tools exist to help quantify perioperative risk and can be used in combination to best educate patients prior to surgery. In this review, we go over the various scoring tools and provide a guide for clinicians to best assess and optimize perioperative risk based on the etiology of liver disease.

Optimal management of chemotherapy-induced thrombocytopenia with thrombopoietin receptor agonists

Chemotherapy-induced thrombocytopenia (CIT) is a common complication of antineoplastic therapy, resulting in antineoplastic therapy dose reductions, treatment delays, treatment discontinuation, and morbid bleeding events. Despite several decades of research into thrombopoietic growth factors in CIT, there are presently no available U.S. FDA- or EMA-approved agents to treat CIT. However, a respectable body of evidence has been published evaluating the thrombopoietin receptor agonists (TPO-RAs) for the management and prevention of CIT in patients with solid tumors, and critical studies are ongoing with the TPO-RAs romiplostim and avatrombopag. When employed in the appropriate patient population and used properly, TPO-RAs can successfully and safely manage CIT for extended periods of time with minimal apparent risks. This comprehensive review discusses the evidence for TPO-RAs in CIT in patients with solid tumors, provides detailed guidance for their use in the clinic, and discusses ongoing essential clinical trials in management of CIT.

Management of chemotherapy-induced thrombocytopenia: guidance from the ISTH Subcommittee on Hemostasis and Malignancy

Thrombocytopenia is a common adverse effect of chemotherapy. The development of chemotherapy-induced thrombocytopenia (CIT) is influenced by cancer type and therapy, occurring in approximately one-third of patients with a solid tumor diagnosis and half of all patients with a hematologic malignancy. CIT may complicate the administration of chemotherapy, leading to therapeutic delays or dose reductions. This guidance document, presented by the International Society on Thrombosis and Haemostasis (ISTH) Subcommittee on Hemostasis and Malignancy, provides a comprehensive summary of the evidence and offers direction on the use of thrombopoietin receptor agonists (TPO-RAs) in various settings of CIT, including solid tumors, acute myeloid leukemia, stem cell transplant, and lymphoma. Studies have shown that TPO-RAs can improve platelet counts in CIT, but the clinical benefits of TPO-RA in terms of reducing bleeding, limiting platelet transfusion, avoiding chemotherapy delay, or dose reduction are uncertain. Further research is needed to optimize the selection of appropriate indications and study design to manage thrombocytopenia following chemotherapy.

A De Novo Frameshift Mutation in RPL5 with Classical Phenotype Abnormalities and Worsening Anemia Diagnosed in a Young Adult-A Case Report and Review of the Literature

Diamond-Blackfan anemia (DBA) is a congenital bone marrow failure syndrome associated with malformations. DBA is related to defective ribosome biogenesis, which impairs erythropoiesis, causing hyporegenerative macrocytic anemia. The disease has an autosomal dominant inheritance and is commonly diagnosed in the first year of life, requiring continuous treatment. We present the case of a young woman who, at the age of 21, developed severe symptomatic anemia. Although, due to malformations, a congenital syndrome had been suspected since birth, a confirmation diagnosis was not made until the patient was referred to our center for an evaluation of her anemia. In her neonatal medical history, she presented with anemia that required red blood cell transfusions, but afterwards remained with a stable, mild, asymptomatic anemia throughout her childhood and adolescence. Her family history was otherwise unremarkable. To explain the symptomatic anemia, vitamin deficiencies, autoimmune diseases, bleeding causes, and myeloid and lymphoid neoplasms were investigated and ruled out. A molecular investigation showed the RPL5 gene variant c.392dup, p.(Asn131Lysfs*6), confirming the diagnosis of DBA. All family members have normal blood values and none harbored the mutation. Here, we will discuss the unusual evolution of this case and revisit the literature.

A Synopsis of Hepatitis C Virus Treatments and Future Perspectives

Hepatitis C virus (HCV) infection is a worldwide public health problem. Chronic infection with HCV can lead to liver cirrhosis or cancer. Although some immune-competent individuals can clear the virus, others develop chronic HCV disease due to viral mutations or an impaired immune response. IFNs type I and III and the signal transduction induced by them are essential for a proper antiviral effect. Research on the viral cycle and immune escape mechanisms has formed the basis of therapeutic strategies to achieve a sustained virological response (SVR). The first therapies were based on IFNα; then, IFNα plus ribavirin (IFN-RBV); and then, pegylated-IFNα-RBV (PEGIFNα-RIV) to improve cytokine pharmacokinetics. However, the maximum SVR was 60%, and several significant side effects were observed, decreasing patients' treatment adherence. The development of direct-acting antivirals (DAAs) significantly enhanced the SVR (>90%), and the compounds were able to inhibit HCV replication without significant side effects, even in paediatric populations. The management of coinfected HBV-HCV and HCV-HIV patients has also improved based on DAA and PEG-IFNα-RBV (HBV-HCV). CD4 cells are crucial for an effective antiviral response. The IFNλ3, IL28B, TNF-α, IL-10, TLR-3, and TLR-9 gene polymorphisms are involved in viral clearance, therapeutic responses, and hepatic pathologies. Future research should focus on searching for strategies to circumvent resistance-associated substitution (RAS) to DAAs, develop new therapeutic schemes for different medical conditions, including organ transplant, and develop vaccines for long-lasting cellular and humoral responses with cross-protection against different HCV genotypes. The goal is to minimise the probability of HCV infection, HCV chronicity and hepatic carcinoma.

Review: Advances in the Pathogenesis and Treatment of Immune Thrombocytopenia Associated with Viral Hepatitis

Hepatitis B virus and hepatitis C virus are the hepatitis subtypes that most commonly induce immune thrombocytopenia (ITP). Although the pathogenesis of viral hepatitis-associated ITP remains unclear, it may involve antibody cross-reactivity due to molecular mimicry, the formation of virus-platelet immune complexes, and T cell-mediated suppression of bone marrow hematopoiesis. Moreover, there is significant correlation between platelet count and the severity of viral hepatitis, the risk of progression to liver cirrhosis, and clinical prognosis. However, treatment of viral hepatitis-associated ITP is hindered by some antiviral drugs. In this review, we summarize research progress to date on the pathogenesis and treatment of viral hepatitis-related ITP, hoping to provide a reference for clinical diagnosis and treatment.

Cost-Effectiveness of Thrombopoietin Mimetics in Patients with Thrombocytopenia: A Systematic Review

OBJECTIVES

Thrombopoietin (TPO) mimetics are a potential alternative to platelet transfusion to minimize blood loss in patients with thrombocytopenia. This systematic review aimed to evaluate the cost-effectiveness of TPO mimetics, compared with not using TPO mimetics, in adult patients with thrombocytopenia.

METHODS

Eight databases and registries were searched for full economic evaluations (EEs) and randomized controlled trials (RCTs). Incremental cost-effectiveness ratios (ICERs) were synthesized as cost per quality-adjusted life year gained (QALY) or as cost per health outcome (e.g. bleeding event avoided). Included studies were critically appraised using the Philips reporting checklist.

RESULTS

Eighteen evaluations from nine different countries were included, evaluating the cost-effectiveness of TPO mimetics compared with no TPO, watch-and-rescue therapy, the standard of care, rituximab, splenectomy or platelet transfusion. ICERs varied from a dominant strategy (i.e. cost-saving and more effective), to an incremental cost per QALY/health outcome of EUR 25,000-50,000, EUR 75,000-750,000 and EUR > 1 million, to a dominated strategy (cost-increasing and less effective). Few evaluations (n = 2, 10%) addressed the four principal types of uncertainty (methodological, structural, heterogeneity and parameter). Parameter uncertainty was most frequently reported (80%), followed by heterogeneity (45%), structural uncertainty (43%) and methodological uncertainty (28%).

CONCLUSIONS

Cost-effectiveness of TPO mimetics in adult patients with thrombocytopenia ranged from a dominant strategy to a significant incremental cost per QALY/health outcome or a strategy that is clinically inferior and has increased costs. Future validation and tackling the uncertainty of these models with country-specific cost data and up-to-date efficacy and safety data are needed to increase the generalizability.

Thrombopoietin receptor agonists for chemotherapy-induced thrombocytopenia: a new solution for an old problem

Chemotherapy-induced thrombocytopenia (CIT) is common, resulting in increased bleeding risk and chemotherapy delays, dose reduction, and treatment discontinuation, which can negatively affect oncologic outcomes. The only agent approved by the US Food and Drug Administration to manage CIT (oprelvekin) was voluntarily withdrawn from the market by the manufacturer, leaving few options for patients. Therefore, patients experiencing CIT present a significant clinical challenge in daily practice. The availability of thrombopoietin receptor agonists has led to formal clinical trials describing efficacy in CIT as well as a rather extensive body of published observational data from off-label use in this setting but no formal regulatory indications for CIT to date. The accumulated data, however, have affected National Comprehensive Cancer Network guidelines, which now recommend consideration of TPO-RA clinical trials as well as off-label use of romiplostim. This review article details the evidence to date for the management of CIT with thrombopoietin receptor agonists (TPO-RAs), discussing the efficacy data, the specific circumstances when treatment is warranted (and when it is generally unnecessary), and safety considerations. Specific recommendations regarding patient selection, initiation, dosing, titration, and discontinuation for TPO-RA therapy in CIT are given, based on published data and expert opinion where evidence is lacking.

Thrombocytopenia in chronic liver disease: Physiopathology and new therapeutic strategies before invasive procedures

Chronic liver disease is characterized by several hematological derangements resulting in a complex and barely rebalanced haemostatic environment. Thrombocytopenia is the most common abnormality observed in these patients and recent advances have led to researchers focus the attention on the multifactorial origin of thrombocytopenia and on the key role of thrombopoietin (TPO) in its physiopathology. Severe thrombocytopenia (platelet count < 50000/μL) complicates the management of patients with chronic liver disease by increasing the potential risk of bleeding for invasive procedures, which may be therefore delayed or canceled even if lifesaving. In the very last years, the development of new drugs which exceed the limits of the current standard of care (platelet transfusions, either immediately before or during the procedure) paves the way to a new scenario in the management of this population of patients. Novel agents, such as the TPO-receptor agonists avatrombopag and lusutrombopag, have been developed in order to increase platelet production as an alternative to platelet transfusions. These agents have demonstrated a good profile in terms of efficacy and safety and will hopefully allow reducing limitations and risks associated with platelet transfusion, without any delay in scheduled interventions. Altogether, it is expected that patients with chronic liver disease will be able to face invasive procedures with one more string in their bow.

Romiplostim for chemotherapy‐induced thrombocytopenia: Efficacy and safety of extended use

Background

Chemotherapy‐induced thrombocytopenia (CIT) is common during treatment with antineoplastic therapies and may adversely impact chemotherapy dose intensity. There is no approved therapy for CIT. In our recent phase II randomized study, romiplostim led to correction of platelet counts in 85% of treated patients and allowed resumption of chemotherapy, with low rates of recurrent CIT in the first two cycles or 8 weeks of chemotherapy. However, there is a lack of long‐term data on the efficacy and safety of romiplostim in CIT.

Objectives

To analyze efficacy and safety of romiplostim in the patients in the phase 2 study, who received romiplostim for ≥1 year.

Patients/Methods

Twenty‐one patients remained on romiplostim for ≥1 year. We analyzed the effect of romiplostim on platelet counts, absolute neutrophil counts, and hemoglobin, as well as impact on ongoing chemotherapy. We also tracked venous or arterial thrombotic events.

Results

During the study period, romiplostim was effective in preventing reduction of chemotherapy dose intensity due to CIT. Fourteen of the 20 (70%) analyzable patients experienced no episode of CIT, 4 subjects experienced a single chemotherapy dose delay due CIT, and 2 patients required a chemotherapy dose reduction. Platelet counts were preserved throughout the duration of the extension analysis. One patient experienced a proximal deep vein thrombosis, and one patient experienced multiple tumor‐related ischemic events.

Conclusions

Long‐term use of romiplostim for treatment of CIT was effective and safe, with no evidence of resistance or increased risk of thrombosis.

COVID-19 Disease and Associated Thrombocytopenia: Pathogenesis and a Clue to the Etiology

(1) Background: Hospital mortality in patients suffering from SARS-CoV-2 infection has been associated with thrombocytopenia. The present study was conducted to establish the correlation of thrombocytopenia and the severity of infection. The impact of IL-1Ra gene polymorphism on the incidence and severity of thrombocytopenia was also studied. (2) Methods: Various biochemical parameters measured in all the 1200 enrolled patients included full blood counts, renal and liver function tests, iron study, inflammatory markers, and coagulation assays. A further 70 patients each were selected from the severe thrombocytopenic and non-thrombocytopenic patient groups to study the IL-1Ra gene polymorphism by RCR. (3) Results: Out of 1200 patients, 436 (36.3%) had thrombocytopenia. Among these patients, 118 (27.1%), 75 (17.2%), and 42 (9.6%) had mild, moderate, severe, and very severe thrombocytopenia, respectively. Severe cases mostly resulted from peripheral consumption (73.5%), hemo-phagocytosis (15.4%), and bone marrow suppression (11.11%). A statistically significant correlation was found between the occurrence and severity of thrombocytopenia with perturbated levels of inflammatory markers and the presence of comorbidities. The IL-1Ra∗3 variant was found to be significantly associated with thrombocytopenia. The IL-1Ra∗2 variant was significantly seen among controls. (4) Conclusions: The present study revealed a significant correlation between thrombocytopenia and the severity of COVID-19 disease. Moreover, the IL-1Ra∗3 variant of IL-1Ra gene was associated with thrombocytopenia.

Impact of Platelet Count on Perioperative Bleeding in Patients With Cirrhosis Undergoing Surgical Treatments of Liver Cancer

In patients with cirrhosis with severe thrombocytopenia (platelet count [PC] <50 × 109 /L) and undergoing invasive procedures, it is common clinical practice to increase the PC with platelet transfusions or thrombopoietin receptor agonists to reduce the risk of major periprocedural bleeding. The aim of our study was to investigate the association between native PC and perioperative bleeding in patients with cirrhosis undergoing surgical procedures for the treatment of hepatocellular carcinoma (HCC). We retrospectively evaluated 996 patients with cirrhosis between 1996 and 2018 who underwent surgical treatments of HCC by liver resection (LR) or radiofrequency ablation (RFA) without prophylactic platelet transfusions. Patients were allocated to the following three groups based on PC: high (>100 × 109 /L), intermediate (51-100 × 109 /L), and low (≤50 × 109 /L). PC was also analyzed as a continuous covariate on multivariable analysis. The primary endpoint was major perioperative bleeding. The overall event rate of major perioperative bleeding was 8.9% and was not found to differ significantly between the high, intermediate, and low platelet groups (8.1% vs. 10.2% vs. 10.8%, P = 0.48). On multivariable analysis, greater age, aspartate aminotransferase, lower hemoglobin, and treatment with LR (vs. RFA) were found to be significant independent predictors of major perioperative bleeding, with associations with disease etiology and year of surgery also observed. After adjusting for these factors, the association between PC and major perioperative bleeding remained nonsignificant. Conclusion: Major perioperative bleeding was not significantly associated with PC in patients with cirrhosis undergoing surgical treatment of HCC, even when their PC was <50 × 109 /L. With the limit of a retrospective analysis, our data do not support the recommendation of increasing PC in patients with severe thrombocytopenia in order to decrease their perioperative bleeding risk.

Catastrophic anti-phospholipid syndrome with Libman-Sacks endocarditis following eltrombopag therapy for immune thrombocytopenic purpura: A case report

BACKGROUND

Immune thrombocytopenic purpura (ITP) is an autoimmune disease, with accelerated destruction of platelets, estimated to affect 1.6-3.9 in 100,000 adults every year in the European Union. Glucocorticoids and intravenous immunoglobulins are common drug therapies. In refractory cases, drugs that enhance thrombopoiesis may be used. Eltrombopag is a thrombopoietin receptor agonist, known to increase platelet count in patients with refractory ITP. Thrombotic adverse events have been described in association with Eltrombopag administration.

CASE REPORT

A young female patient of Ethiopian ancestry with systemic lupus erythematosus, triple Antiphospholipid (APLA) positive serology and refractory ITP who received Eltrombopag and 2 weeks later developed catastrophic APLA syndrome with severe Libman-Sacks endocarditis of the mitral and aortic valves, multiple intracerebral infracts and arterial thrombosis of the left upper limb.

CONCLUSION

Eltrombopag is a salvage drug, used in refractory ITP. Thrombotic adverse events, some of which may be life-threatening, are a possible complication, especially in high-risk patients.

Clinical challenges and promising therapies for chemotherapy-induced thrombocytopenia

Introduction: Chemotherapy-induced thrombocytop enia (CIT) is a common complication of cancer treatment causing chemotherapy delays, dose reductions, and treatment discontinuation, negatively impacting treatment outcomes and putting patients at risk for bleeding complications. There is no FDA-approved agent available to manage CIT.Areas covered: This article covers the diagnosis, definitions, and clinical challenges of CIT, and then focuses on the therapeutics developed to manage CIT. The first-generation thrombopoietic agents (oprelvekin and recombinant human thrombopoietins) are reviewed for critical background and context, followed by a detailed discussion of the data for the thrombopoietin receptor agonists (TPO-RAs) to manage CIT. Efficacy of TPO-RAs in treatment and prevention of CIT, as well as safety concerns such as the risk of thromboembolic complications, are reviewed in detail. For this review, a PubMed/MEDLINE literature search was undertaken for relevant articles published from 1995-2021.Expert opinion: After over two decades of drug development for CIT, multiple clinical trials and observational studies have found TPO-RAs, in particular romiplostim, to be safe and effective agents to manage patients with CIT, although no agent is yet FDA-approved for this indication. Active management of CIT with TPO-RAs is likely to improve oncologic outcomes, although additional data are needed. Phase 3 trials are ongoing.

A multicenter study of romiplostim for chemotherapy-induced thrombocytopenia in solid tumors and hematologic malignancies

Chemotherapy-induced thrombocytopenia (CIT) frequently complicates cancer treatment causing chemotherapy delays, dose reductions, and discontinuation. There is no FDA-approved agent available to manage CIT. This study retrospectively evaluated patients with CIT treated on institutional romiplostim treatment pathways at 4 U.S. centers. The primary outcome was achievement of a romiplostim response [median on-romiplostim platelet count (Plt) ≥75x109/L and ≥30x109/L above baseline]. Secondary outcomes included time to Plt≥100x109/L and rates of the following: Plt<100x109/L, Plt<75x109/L, Plt<50x109/L, thrombocytosis, chemotherapy dose reduction/treatment delay, platelet transfusion, bleeding, and thromboembolism. Multivariable regression was used to identify predictors of romiplostim non-response and compare weekly dosing with intracycle/intermittent dosing. 173 patients (153 solid tumor, 20 lymphoma or myeloma) were treated, with 170 (98%) receiving a median of 4 (range, 1-36) additional chemotherapy cycles on romiplostim. Romiplostim was effective in solid tumor patients: 71% of patients achieved a romiplostim response, 79% avoided chemotherapy dose reductions/treatment delays and 89% avoided platelet transfusions. Median per-patient Plt on romiplostim was significantly higher than baseline (116x109/L vs. 60x109/L, P<0.001). Bone marrow tumor invasion, prior pelvic irradiation, and prior temozolomide predicted romiplostim non-response. Bleeding rates were lower than historical CIT cohorts and thrombosis rates were not elevated. Weekly dosing was superior to intracycle dosing with higher response rates and less chemotherapy dose reductions/treatment delays (IRR 3.00, 95% CI 1.30-6.91, P=0.010) or bleeding (IRR 4.84, 95% CI 1.18-19.89, P=0.029). Blunted response (10% response rate) was seen in non-myeloid hematologic malignancy patients with bone marrow involvement. In conclusion, romiplostim was safe and effective for CIT in most solid tumor patients.

Evolution of views and modern concepts of the state of the hemostasis system in liver cirrhosis

Aim. To study the state of individual elements of the hemostasis system in liver cirrhosis according to modern literature.

Summary. The review presents an analysis of literature data covering the state of the homeostasis system in liver cirrhosis. The pathophysiological and pathogenetic mechanisms that underlie the disorders that occur in various parts of the hemostatic system in this pathology are described in a polemical style. Literature data concerning a relatively littlestudied aspect of cirrhosis – hypercoagulation are analyzed. From the standpoint of modern concepts and taking into account the peculiarities of hemostasis disorders, the pathogenetic significance of the vascular endothelium and endothelial dysfunction is postulated. As well as the role of inflammatory mediators in the development of coagulopathy and intravascular coagulation syndrome in patients with cirrhosis of the liver.

Eltrombopag inhibits Type I interferon-mediated antiviral signaling by decreasing cellular iron

Thrombocytopenia is common among patients with viral hepatitis, limiting the use of antiviral therapy. Eltrombopag (EP) is a thrombopoietin receptor (TPO-R) agonist that has been approved for treatment of immune thrombocytopenia patients with hepatitis virus infection. Interferon-α (IFN-α) plays a crucial role in the antiviral response, and is recommended as the first-line agent for chronic hepatitis B patients. Here, we investigated whether EP inhibits the production of IFN-stimulated genes (ISGs) induced by IFN-α through the TPO-R-independent pathway by mediating reactive oxygen species production by iron chelation. Our results assessed the inhibitory effect of EP on IFN-α signaling, which contributes to the downregulation of ISGs produced by monocytes and sheds light on the underlying mechanisms using iron chelation to treat patients with hepatitis-related immunological thrombocytopenia.

An evaluation of avatrombopag for the treatment of thrombocytopenia

Introduction: The thrombopoietin receptor agonists (TPO-RAs) are a class of drugs that have been FDA-approved for immune thrombocytopenia (ITP), periprocedural thrombocytopenia in patients with chronic liver disease (CLD), aplastic anemia, and thrombocytopenia associated with antiviral treatment of hepatitis C. Avatrombopag is a TPO-RA that is currently FDA-approved for ITP and periprocedural thrombocytopenia in patients with CLD and is currently undergoing evaluation for chemotherapy-induced thrombocytopenia (CIT) in an international phase III clinical trial. Areas covered: This paper summarizes the chemistry, pharmacodynamics, and pharmacokinetics of avatrombopag. In addition, the authors review the efficacy and safety of avatrombopag, covering clinical trials in patients with ITP and in patients with CLD scheduled to undergo a procedure. Expert opinion: Avatrombopag has demonstrated efficacy in patients with ITP. With its low side-effect burden, absence of hepatotoxicity, ease of use as an oral medication, and lack of food-drug interactions, avatrombopag is a favorable option for ITP, though there is a lack of long-term safety data. In periprocedural thrombocytopenia in patients with CLD, avatrombopag is comparable to lusutrombopag, another TPO-RA. Finally, the results of the study of avatrombopag in CIT are eagerly awaited, as there are no currently approved medications for this indication in the USA.

Review article: a treatment algorithm for patients with chronic liver disease and severe thrombocytopenia undergoing elective medical procedures in the United States

BACKGROUND

Thrombocytopenia is the most common haematological abnormality in patients with chronic liver disease in the United States. Severe thrombocytopenia (platelet count <50 × 10⁹ /L) can complicate the management of patients with chronic liver disease by significantly increasing the potential risk of bleeding during or after invasive procedures. The current standard-of-care treatment for severe thrombocytopenia is platelet transfusion. Novel agents that target the thrombopoietin pathway, including receptor agonists avatrombopag and lusutrombopag, have recently shown promise in clinical trials as alternatives to platelet transfusion.

AIM

To review treatment options for severe thrombocytopenia, including platelet transfusion and thrombopoietin-receptor agonists, with the aim of producing a simplified treatment algorithm.

METHODS

Five liver disease specialists were assigned sections of the manuscript to research and present at a consensus meeting in April 2019, with the goal of creating an easy-to-use, effective treatment plan for severe thrombocytopenia in patients with chronic liver disease.

RESULTS

Through discussion and collaborative decision making, a simplified algorithm was developed to provide guidance to healthcare professionals on treating severe thrombocytopenia in patients with chronic liver disease undergoing elective medical procedures in the United States. As part of these guidelines, we outline the use of the US Food and Drug Administration-approved thrombopoietin receptor agonists avatrombopag and lusutrombopag as well tolerated and effective alternatives to platelet transfusion.

CONCLUSIONS

This algorithm provides guidance for the management of severe thrombocytopenia to reduce bleeding risks in patients with chronic liver disease undergoing elective procedures, while reducing requirement for platelet transfusion.

Eltrombopag Use for Treatment of Thrombocytopenia in a Patient with Chronic Liver Disease and Portal Vein Thrombosis: Case Report

Off-label drug use refers to drug use beyond the specifications authorized for marketing [J Med Case Rep. 2014 Dec;8(1):303]. Eltrombopag is a thrombopoietin receptor agonist that has been used in treating thrombocytopenia due to chronic liver disease (CLD) as an off-label medication. Treatment of thrombocytopenia in patients with CLD constitute a real dilemma as the options are limited and some of them are invasive. However, thrombopoietin receptor agonist has been increasingly used for this purpose. Here we report a 34-year-old woman who has been diagnosed with CLD due to autoimmune hepatitis 20 years ago. Her condition was complicated with portal vein thrombosis, chronic thrombocytopenia, and variceal hemorrhage, and she has been listed as a candidate for liver transplantation. Given her high risk of bleeding, we started her on low dose of eltrombopag (25 mg daily) in order to maintain a platelet level of ≥50 × 10³/µL. However, 1 year after initiation of the therapy, she developed left lower limb deep vein thrombosis.

Thrombopoietin Receptor Agonists in Patients with Chronic Liver Disease

Thrombocytopenia is one of the most common hematologic complications in cirrhosis. Despite limited data linking platelet count and bleeding risk in patients with cirrhosis, the use of platelets transfusions for invasive procedures has been a common practice. Recently, thrombopoietin (TPO) receptor agonists have been approved for use in patients with chronic liver disease (CLD) undergoing invasive procedures. The aim of this study was to review current literature on bleeding risk in patients with cirrhosis and the use of platelet transfusions and TPO receptor agonists in the context of invasive procedures. PubMed search was conducted to find articles relating to cirrhosis, thrombocytopenia, and new novel treatments for this condition. Search terms included CLD, cirrhosis, thrombocytopenia, bleeding, thrombosis, coagulopathy, hemostasis, and TPO receptor agonists. Romiplostim, eltrombopag, avatrombopag, and lusutrombopag are approved TPO receptor agonists, with avatrombopag and lusutrombopag specifically approved for use in patients with CLD undergoing invasive procedures. In patients with platelet counts < 50,000/mm³, avatrombopag and lusutrombopag increased the platelet counts above this threshold in the majority of treated patients and reduced the frequency of platelet transfusions. At the approved doses, incidence of thrombosis was not increased and therapies were well tolerated. Studies were not powered to assess whether risk of bleeding complications was reduced and the fundamental question of whether correction of thrombocytopenia is warranted in patients undergoing invasive procedures remains unanswered. The use of TPO receptor agonists has resulted in less requirement for platelet transfusions. In patients with cirrhosis undergoing invasive procedures for whom platelet transfusion is planned, TPO receptor agonists are an alternative and avoid the risks associated with transfusions. However, there is need for a thoughtful approach to manage bleeding risk in patients with cirrhosis undergoing procedures, with the consideration of a comprehensive hemostatic profile, the severity of portal hypertension, and the complexity of the invasive procedure to guide decisions regarding transfusions or use of TPO receptor agonists.

Thrombocytopenia in Chronic Liver Disease: New Management Strategies

Thrombocytopenia is common in advanced liver disease, and such patients frequently need invasive procedures. Numerous mechanisms for thrombocytopenia exist, including splenic sequestration and reduction of levels of the platelet growth factor thrombopoietin. Traditionally, platelet transfusions have been used to increase platelet counts before elective procedures, usually to a threshold of greater than or equal to 50,000/μL, but levels vary by provider, procedure, and specific patient. Recently, the thrombopoietin receptor agonists avatrombopag and lusutrombopag were studied and found efficacious for increasing platelet count in the outpatient setting for select patients with advanced liver disease who need a procedure.

Pathogenesis of Thrombocytopenia in Chronic HCV Infection: A Review

A large proportion of patients with chronic hepatitis C have associated thrombocytopenia (TCP). Due to bleeding risks, TCP, when severe, can limit diagnostic and therapeutic procedures, treatments, and increases risk of complications, especially excessive bleeding. It is important to understand the mechanisms that cause TCP in order to manage it. In general, TCP can be due to increased destruction or decreased production. Proposed mechanisms of increased destruction include autoantibodies to platelets and hypersplenism with sequestration. Proposed mechanisms of decreased production include virus-induced bone marrow suppression and decreased TPO production. Autoantibodies directed against platelet surface antigens have demonstrated an inverse correlation with platelet counts. Hypersplenism with sequestration involves the interaction of portal hypertension, splenomegaly, and platelet destruction. Decreased production mechanisms involve appropriate and inappropriate levels of TPO secretion. There is limited evidence to support viral-induced bone marrow suppression. In contrast, there is strong evidence to support low levels of TPO in liver failure as a major cause of TCP. TPO-agonists, specifically eltrombopag, have been shown in hepatitis C patients to increase platelet counts without reducing portal hypertension or splenomegaly. We conclude that TCP in hepatitis C virus-induced liver disease is often multifactorial, but an understanding of the mechanisms can lead to judicious use of new drugs for treatment.

The role of romiplostim for pediatric patients with immune thrombocytopenia

The thrombopoietin receptor agonists (TPO-RAs) are a class of platelet growth factors used to treat immune thrombocytopenia (ITP) in children and adults. Romiplostim is a peptide TPO-RA approved for over a decade to treat adults with ITP but was just recently US Food and Drug Administration approved to manage ITP in children 1 year of age and older who have had an inadequate response to corticosteroids, intravenous immunoglobulin, or splenectomy. Like the small molecule TPO-RA eltrombopag, romiplostim offers a high clinical response rate in pediatric patients with ITP, but requires use over an extended, and possibly indefinite, duration. This review is a critical appraisal of the role of romiplostim in pediatric ITP, discussing the safety and efficacy of this agent in clinical trials of children and adults and defining the patients most likely to benefit from romiplostim treatment. The treating hematologist is additionally provided guidance with treatment goals, dosing strategies, toxicity management, and indications for discontinuation.

Management of Hepatic Coagulopathy in Bleeding and Nonbleeding Patients: An Evidence-Based Review

Patients with varying degrees of hepatic dysfunction often present with presumed bleeding diathesis based on interpretation of routine measures of coagulation (prothrombin time [PT], international normalized ratio [INR], and activated partial thromboplastin time). However, standard markers of coagulation do not reflect the actual bleeding risk in this population and may lead to inappropriate administration of hemostatic agents and blood products. The concept of "rebalanced hemostasis" explains both the risk of bleeding and clotting seen in patients with liver dysfunction. The role of pharmacologic agents and blood products for prevention of bleeding during high-risk procedures and treatment of clinically significant bleeding remains unclear. Viscoelastic measurements of the clotting cascade provide information about platelets, fibrinogen/fibrin polymerization, coagulation factors, and fibrinolysis that might better represent hemostasis in vivo and may better inform management strategies. Due to the paucity of available data, firm recommendations for the use of blood products and pharmacologic agents in patients with hepatic coagulopathies are lacking, and thus, these products should not be routinely administered. Traditional laboratory tests such as PT/INR should not be the sole determinant of potential interventions. Rather, clinicians should assess factors such as the severity of bleed or bleeding risk of the procedure, the patient's risk of thromboembolism, and the strength of available evidence for specific agents and blood products to guide decision-making.

Platelets in chronic liver disease, from bench to bedside

In the last decade, numerous studies revealed physiologic and pathophysiologic roles of platelets beyond haemostasis, a process to prevent and stop bleeding. These include the activation of the immune system and the promotion of inflammation, infection and cancer. Hence, the emerging view on the role of platelets has shifted - platelets are now seen as alert "sentinels" of the immune compartment, rather than passive bystanders. Herein, we review well-established and newly discovered features of platelets that define their natural role in maintaining blood haemostasis, but also their functional relationship with other cells of the immune system. We focus on recent studies underlining functional involvement of platelets in chronic liver diseases and cancer, as well as the effects of anti-platelet therapy in these contexts. Finally, we illustrate the potential of platelets as possible diagnostic and therapeutic tools in liver disease based on recently developed methodologies.

Current Advance in Thrombopoietin Receptor Agonists in the Management of Thrombocytopenia Associated With Chronic Liver Disease: Focus on Avatrombopag

Chronic liver disease (CLD) is a condition that progresses over time toward advanced disease state which is known as liver cirrhosis. Liver cirrhosis leads to dangerous health problems among people living across the world. One such problem that observed in about 75% of cirrhotic patients is thrombocytopenia; which in turn associated with poor prognosis and recovery from CLD. Beyond these, thrombocytopenia in cirrhotic patients led to impairment of coagulation cascade and significantly influenced the utilization of effective mechanism in the management of CLD. By nature, treatment of CLD involves invasive diagnostic and treatment procedures; therefore, in the presence of thrombocytopenia implementing these methods put the lives of patients in a critical health problem due to increased risk of bleeding and mortality. Because of these reasons, prophylactic transfusion of platelets is considered to be one of the most effective options that reduce the risk of bleeding in patients with CLD that required to undergo an invasive procedure. Although platelet transfusion presented with significant advantages in facilitating the invasive procedure in patients with CLD, refractoriness with repeated use and various problems associated with its transfusion limit the continuous utilization of this important option. With these challenges and current advance in the knowledge of thrombopoiesis, the development of relatively safe and alternative drugs that enhance the production of platelets by interacting with thrombopoietin receptor agonists provides a promising option to platelet transfusion. The discovery and approval of romiplostim and eltrombopag in August 2008 and November 2008, respectively, for the treatment of chronic immune thrombocytopenia paved a way and followed by the Food and Drug Administration (FDA) approval of 2 potentially advantageous drugs, lusutrombopag, and avatrombopag, in 2018 for the treatment of thrombocytopenia in patients with CLD that required to undergo elective surgery. Therefore, this review aims to assess pathogenesis of thrombocytopenia and its challenges in the management of liver-related issues and, more importantly, gives emphasis to address the potential use of avatrombopag in the treatment of thrombocytopenia underlying CLD, its pharmacokinetics and pharmacodynamics, as well as its toxicological profiles by presenting the most commonly reported adverse events in various trials.

Lusutrombopag for the Treatment of Thrombocytopenia in Patients With Chronic Liver Disease Undergoing Invasive Procedures (L-PLUS 2)

Thrombocytopenia may be associated with increased bleeding risk impacting timing and outcome of invasive procedures in patients with chronic liver disease (CLD). Lusutrombopag, a small-molecule, thrombopoietin (TPO) receptor agonist, was evaluated as a treatment to raise platelet counts (PCs) in patients with thrombocytopenia and CLD undergoing invasive procedures. L-PLUS 2 was a global, phase 3, randomized, double-blind, placebo-controlled study. Adults with CLD and baseline PCs < 50 × 10⁹ /L were randomized to receive once-daily lusutrombopag 3 mg or placebo ≤ 7 days before an invasive procedure scheduled 2-7 days after the last dose. The primary endpoint was avoidance of preprocedure platelet transfusion and avoidance of rescue therapy for bleeding. A key secondary endpoint was number of days PCs were ≥ 50 × 10⁹ /L throughout the study. Safety analysis was performed on patients who received at least one dose of study drug. This study occurred between June 15, 2015, and April 19, 2017, with a total of 215 randomized patients (lusutrombopag, 108; placebo, 107); 64.8% (70/108) of patients in the lusutrombopag group versus 29.0% (31/107) in the placebo group met the primary endpoint (P < 0.0001; difference of proportion 95% confidence interval [CI], 36.7 [24.9, 48.5]). The median duration of PCs ≥ 50 × 10⁹ /L was 19.2 days with lusutrombopag (without platelet transfusion) compared with 0.0 in the placebo group (with platelet transfusion) (P = 0.0001). Most adverse events were mild or moderate in severity, and rates were similar in the lusutrombopag and placebo groups (47.7% and 48.6%, respectively). Conclusion: Lusutrombopag was superior to placebo for reducing the need for platelet transfusions and achieved durable PC response in patients with thrombocytopenia and CLD undergoing invasive procedures, with a safety profile similar to placebo.

Management of Thrombocytopenia in Patients with Chronic Liver Disease

BACKGROUND

Thrombocytopenia is the most common hematologic complication associated with chronic liver disease (CLD) with important clinical implications. While the mechanisms for thrombocytopenia are multifactorial, platelet sequestration in the spleen and decreased thrombopoietin (TPO) production are the main mechanisms in patients with CLD.

AIM

This review outlines the current treatment options for thrombocytopenia in patients with CLD, explores their limitations, and proposes a revised treatment algorithm for the management of thrombocytopenia in this patient group.

METHODS

A PubMed search of the literature was undertaken with search terms focused on CLD and thrombocytopenia.

RESULTS

Until now, the standard-of-care treatment in these patients has been the use of platelet transfusions either prophylactically or periprocedurally to control bleeding. Treatment options, such as splenic artery embolization and splenectomy, are invasive, and their utility is limited by significant complications. The US Food and Drug Administration recently approved 2 s-generation TPO-receptor agonists, avatrombopag and lusutrombopag, as safe and effective therapies for the treatment of thrombocytopenia in patients with CLD scheduled to undergo a procedure.

CONCLUSIONS

The addition of avatrombopag and lusutrombopag offers physicians an alternative to platelet transfusions in patients with CLD who have to undergo medical/dental procedures that could potentially put them at an increased risk of bleeding. There are several other drugs in the research pipeline at various stages of development, including a new class of monoclonal antibodies that can bind to and activate TPO-receptor agonists. The outlook for treatment choices for thrombocytopenia in patients with liver disease is promising.

Avatrombopag for the treatment of immune thrombocytopenia and thrombocytopenia of chronic liver disease

Avatrombopag is an orally-administered small molecule thrombopoietin receptor agonist. It was the third thrombopoietin receptor agonist approved for the treatment of immune thrombocytopenia and the first approved to treat periprocedural thrombocytopenia in patients with chronic liver disease (thereby providing an alternative to blood transfusions for these patients). Unlike eltrombopag, avatrombopag does not require a 4 hr food-restricted window around its use and it has not been associated with hepatotoxicity in ITP patients or portal vein thrombosis in patients with chronic liver disease. In ITP patients it can often be dosed less frequently than once daily. It is overall well-tolerated with a side-effect profile similar to placebo in randomized clinical trials. This article will review the clinical development, efficacy, safety, and pharmacology of avatrombopag for use in patients with ITP and thrombocytopenia of chronic liver disease.

Thrombocytopenia and Procedural Prophylaxis in the Era of Thrombopoietin Receptor Agonists

Thrombocytopenia is common in patients with advanced liver disease. These patients frequently require invasive diagnostic or therapeutic procedures in the setting of thrombocytopenia. A common platelet goal before such procedures is ≥50,000/μL, but target levels vary by provider and the procedure. Platelet transfusion has disadvantages, including safety and cost. No other short‐term options for ameliorating thrombocytopenia before procedures were available until the thrombopoietin receptor agonists were recently approved. Avatrombopag and lusutrombopag can be used in certain patients with thrombocytopenia due to advanced liver disease undergoing elective invasive procedures; these new agents are highly effective in carefully selected patients, and real world data of safety and efficacy are awaited.

TPO receptor agonists are an exciting new development that can raise platelet counts in liver patients with thrombocytopenia before elective procedures. We review the strategies to address peri‐procedure thrombocytopenia including data on the most recent trials involving TPO receptor agonists.

Anticoagulation in the cirrhotic patient

In the past, patients with liver cirrhosis were thought to be prone to increased bleeding risk. However, those with compensated liver cirrhosis actually have normal coagulative balance, which can become altered when liver function worsens, or infection, bleeding, or acute kidney insufficiency occur. When this happens, it is now recognized that patients with liver cirrhosis are at higher risk of thrombotic rather than haemorrhagic complications. Anticoagulation plays a favourable role both when used therapeutically or prophylactically. Successful anticoagulation is associated with a lower rate of decompensation and with improved survival. To date, treatment has involved the use of low molecular weight heparins and vitamin K antagonists. Preliminary data suggest that novel non-vitamin K antagonist oral anticoagulants can be used safely in patients with liver cirrhosis.

Eltrombopag enables initiation and completion of pegylated interferon/ribavirin therapy in Japanese HCV-infected patients with chronic liver disease and thrombocytopenia

To investigate the efficacy of eltrombopag for the treatment of thrombocytopenia in patients with chronic hepatitis C, a phase II, single-arm, open-label study with a 9-week pre-antiviral phase was conducted, followed by a 48-week antiviral phase and a 24-week follow-up phase. The proportion of patients who achieved a platelet count threshold, the proportion of patients who maintained a platelet count >50,000/µl, sustained virological response (SVR) rates and safety parameters were evaluated. Of the 45 enrolled patients (median age, 59 years; median platelet count, 63,000/µl; 98% with Child-Pugh class A), 43 (96%) achieved the platelet count threshold during the pre-antiviral phase. A total of 13 patients (29%) experienced ≥1 adverse event (AE), of which headache and vomiting were the most common, and 41 patients (mostly receiving eltrombopag 12.5 mg or 25 mg) entered the antiviral phase, of which 36 (88%) maintained the platelet count threshold; no patient platelet count decreased below 25,000/µl. Nine patients (22%) achieved an SVR at the 24-week follow-up. Grade ≥3 AEs occurred in 25 patients (61%). A total of 8 serious AEs occurred in five patients (12%). No mortality, thromboembolic events (TEEs), or cataract progression were reported. Eltrombopag increased the platelet count in chronic hepatitis C virus-infected patients with cirrhosis and thrombocytopenia and enabled them to initiate and complete interferon-based antiviral therapy (NCT01636778; first submitted: July 05, 2012).

Thrombopoietin receptor agonists: ten years later

The two thrombopoietin receptor agonists (TPO-RA), eltrombopag and romiplostim, were licensed in the US for treatment of immune thrombocytopenia (ITP) in 2008 and, since then, their use has progressively increased around the world; they are currently used in more than 100 countries. The six largest randomized controlled trials conducted in ITP have used one of these two agents. All studies have demonstrated a platelet response rate between 50-90%, depending on the criteria used, with good safety and tolerability. TPO-RA were shown to be effective in reducing bleeding and the need for concomitant or rescue medication. Many other investigations of their mechanism of effect, prospective and retrospective trials, and studies focusing on toxicity have been performed widening our knowledge of these two agents. Initial concerns on issues such as myelofibrosis have not been confirmed. Only a small number of patients develop moderate-severe reticulin fibrosis and/or collagen fibrosis; however, these are usually reversed after discontinuation of TPO-RA. Studies indicate, however, that TPO-RA may increase the risk of venous thromboembolism. Both TPO-RA are currently approved in patients with chronic ITP aged >1-year who are refractory to at least one other treatment. Eltrombopag has acquired two additional indications: severe aplastic anemia refractory to first-line treatment and hepatitis C patients undergoing treatment with interferon-ribavirin. Despite these wide-ranging studies, important questions still need to be answered. This summary review on TPO-RA will summarize what is known regarding efficacy in ITP, evaluate safety concerns in more depth, and focus on the questions that remain.

Optimal use of thrombopoietin receptor agonists in immune thrombocytopenia

The thrombopoietin receptor agonists (TPO-RAs) are a class of platelet growth factors commonly used to treat immune thrombocytopenia (ITP). There are three agents that have been investigated for the treatment of chronic ITP: the peptide agent romiplostim and the small molecule agents eltrombopag and avatrombopag. These agents offer a higher clinical response rate than most other ITP therapies but may require indefinite use. This review is a critical appraisal of the TPO-RAs in adult ITP, defining the optimal patient groups to receive these agents and assisting the hematologist with agent choice, goals of treatment, dosing strategies, and toxicity management. Use of endogenous thrombopoietin levels to predict response to eltrombopag and romiplostim treatment is discussed and alternative dosing protocols suited for certain patient subgroups are described. Finally, indications for discontinuation and combination therapy with other agents are considered.

Avatrombopag for the treatment of immune thrombocytopenia

INTRODUCTION

Thrombopoietin-receptor agonists (TPO-RAs) are the only American Society of Hematology (ASH) guideline-advocated, second-line treatment for immune thrombocytopenia (ITP) that have been validated by randomized, controlled trials with a placebo comparator. Avatrombopag is a new candidate in this class that has been investigated as a treatment option for the treatment of ITP. Areas covered: In this Drug Profile, we provide a review of the clinical data of avatrombopag, which was approved in May 2018 by the United States Food and Drug Administration (FDA) for the treatment of thrombocytopenia in patients with chronic liver disease undergoing an invasive procedure, and an opinion of its potential place in the current evidence-based ITP treatment landscape. Expert commentary: Avatrombopag induces doubling of platelet counts, increasing them to above 50 X 10⁹/L, and prevents the need for platelet transfusions while minimizing the need for rescue medications. Treatment-emergent adverse events (TEAEs) are comparable to placebo. Oral delivery, a 5-day dosing schedule and good tolerability (<1% discontinuation rate) with no clinically significant hepatoxicity make it a promising entrant as a potential second-line treatment for ITP. Further, data from a phase 3 study in patients with ITP supports its utility in the treatment of patients with ITP.

Improvement in hepatitis C virus patients with advanced, compensated liver disease after sustained virological response to direct acting antivirals

BACKGROUND

The outcome of patients with chronic hepatitis C virus infection (HCV) and advanced, compensated liver disease after sustained virological response (SVR) to direct-acting antivirals (DAAs) has not yet been completely depicted. We aimed to assess the clinical, biochemical and instrumental outcome of patients with advanced, compensated chronic HCV-related liver disease with DAA-induced SVR to DAAs and who had at least 1-year follow-up.

MATERIALS AND METHODS

Fifty-two patients with cirrhosis (n = 27) and fibrosis stage F3 (n = 25) followed up for a median of 60 weeks after successful DAA treatment were included. Laboratory work-up, including APRI and FIB-4 scores, liver transient elastography and measurement of the spleen bi-polar diameter were carried out before treatment and at the end of follow-up.

RESULTS

Liver stiffness decreased (P < 0.0001) from a median baseline of 15.2 kPa (12.0-20.0) to 9.3 kPa (7.5-12.0) at follow-up. A liver stiffness value suggestive of the presence (ie, ≥21.0 kPa) of clinically significant portal hypertension was found in 13 patients (25.0%) at baseline and in seven patients (13.5%) at follow-up (P = 0.037). Both APRI (P < 0.0001) and FIB-4 score (P = 0.025) progressively decreased, while platelet count increased (143 × 10⁹ /L [117-176] to 153 × 10⁹ /L [139-186], P = 0.003), and spleen bi-polar diameter decreased (120 mm [112-123] to 110 mm [102-116], P = 0.0009) from baseline to the end of follow-up.

CONCLUSIONS

In patients advanced, compensated chronic liver disease, liver stiffness significantly improves in the long-term after SVR, and this improvement is accompanied by an amelioration of indirect indices of liver fibrosis and function, and by a decrease in parameters of portal hypertension.

Predictors for eltrombopag response in patients with hepatitis C virus-associated thrombocytopenia

BACKGROUND AND AIMS

Thrombocytopenia is a common hematological abnormality observed in patients infected with hepatitis C virus (HCV). The use of eltrombopag has been approved for HCV-associated thrombocytopenia. This is the first study aiming to determine the predictive factors of response to eltrombopag therapy in patients with HCV-associated thrombocytopenia.

PATIENTS AND METHODS

This prospective study was carried out on 130 patients with chronic HCV-associated thrombocytopenia (<50,000×109/L) that precludes the initiation of HCV therapy. Eltrombopag was initiated at a dose of 25 mg once daily; the dose was adjusted with 25 mg increments every 2 weeks to achieve the target platelet count. The primary end point was to achieve stable target platelet count (50,000-100,000×109/L) required to initiate antiviral therapy.

RESULTS

Treatment response was achieved in 111 (85.38%) patients. This prospective study showed that megakaryocyte hypoplasia or aplasia and splenectomy were independent risk factors for eltrombopag nonresponse in chronic HCV-associated thrombocytopenic patients.

CONCLUSION

Eltrombopag is safe and effective for patients with HCV-associated thrombocytopenia. Bone marrow examination should be considered before initiating treatment with eltrombopag in chronic HCV-associated thrombocytopenic patients, especially in patients with splenectomy.