Eltrombopag: a review of its use in the treatment of thrombocytopenia in patients with chronic hepatitis C

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.

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).

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.

Thrombocytopenia and infections

INTRODUCTION

Acquired thrombocytopenia recognizes a myriad of causes. Among these, infectious diseases play a relevant role since a low platelet count is commonplace along with other abnormal laboratory data. Areas covered: This narrative review, after a brief presentation of the possible pathogenic mechanisms, is focused on the most prevalent infections associated with thrombocytopenia, namely those attributable to hepatitis C virus (HCV), human immunodeficiency virus (HIV) and Helicobacter pylori. Expert commentary: An underlying HCV or HIV infection should always be suspected in patients at risk who present with isolated thrombocytopenia. The eradication of Helicobacter pylori is advisable in infected patients with secondary immune thrombocytopenia, because this will increase the platelet count in a substantial number of cases, thus avoiding more aggressive and prolonged treatments.

Lusutrombopag: First Global Approval

Lusutrombopag (Mulpleta®) is an orally bioavailable, small molecule thrombopoietin (TPO) receptor agonist being developed by Shionogi for chronic liver disease (CLD) patients with thrombocytopenia prior to elective invasive surgery. Lusutrombopag acts selectively on the human TPO receptor and activates signal transduction pathways that promote the proliferation and differentiation of bone marrow cells into megakaryocytes, thereby increasing platelet levels. In September 2015, lusutrombopag received its first global approval in Japan for the improvement of CLD-associated thrombocytopenia in patients scheduled to undergo elective invasive procedures. This article summarizes the milestones in the development of lusutrombopag leading to this first approval.

Management of Thrombocytopenia in Chronic Liver Disease: Focus on Pharmacotherapeutic Strategies

Thrombocytopenia (platelet count <150 × 10⁹/L) often complicates chronic liver disease, impeding optimal management of these patients. The prevalence of this manifestation ranges from 6 % among non-cirrhotic patients with chronic liver disease to 70 % among patients with liver cirrhosis. It has also been shown that the severity of liver disease is associated with both prevalence and level of thrombocytopenia. Its development is often multifactorial, although thrombopoietin is thought to be a major factor. The discovery of and ability to clone thrombopoietin led to new treatment opportunities for this clinical manifestation. This review discusses data on the three most important thrombopoietin receptor agonists: eltrombopag, avatrombopag, and romiplostim. Currently, only eltrombopag is approved for usage among patients with thrombocytopenia and chronic hepatitis C virus infection in order to initiate and maintain interferon-based antiviral treatment. Nevertheless, the optimal management of hematologic abnormalities among patients with chronic liver disease, and its risk for bleeding complications, is still a matter of discussion. Thrombocytopenia definitely contributes to hemostatic defects but is often counterbalanced by the enhanced presence of procoagulant factors. Therefore, a thorough assessment of the patient’s risk for thrombotic events is essential when the use of thrombopoietin receptor agonists is considered among patients with chronic liver disease and thrombocytopenia.

Eltrombopag: a review of its use in patients with severe aplastic anaemia

Eltrombopag (Promacta®) is an orally active thrombopoietin receptor agonist recently approved in the US for the treatment of patients with severe aplastic anaemia who have had an insufficient response to immunosuppressive therapy. This article reviews the efficacy and tolerability of eltrombopag in this indication and overviews its pharmacological properties. Eltrombopag does not compete with thrombopoietin and binds to a different site on the receptor, producing additive effects. It stimulates haematopoietic stem cells and promotes haematopoietic recovery in patients with aplastic bone marrow. Eltrombopag increased platelet counts and can also increase red blood cell and neutrophil counts. In patients with severe aplastic anaemia refractory to prior immunosuppressive therapy, oral eltrombopag at dosages ≤150 mg once daily for 12-16 weeks produced a haematological response in at least one cell lineage in 40 % of patients. Trilineage responses were achieved in nearly one-half of the responders during extended treatment. In robust responders, stable haematological counts were maintained after eltrombopag discontinuation. Eltrombopag was generally well tolerated, with increased liver transaminases as the only dose-limiting toxicity. Clonal cytogenetic abnormalities were observed in 19 % of patients and dysplasia in 5 % of patients.

Human platelets and their capacity of binding viruses: meaning and challenges?

Blood platelets are first aimed at ensuring primary hemostasis. Beyond this role, they have been acknowledged as having functions in the maintenance of the vascular arborescence and, more recently, as being also innate immune cells, devoted notably to the detection of danger signals, of which infectious ones. Platelets express pathogen recognition receptors that can sense bacterial and viral moieties. Besides, several molecules that bind epithelial or sub-endothelial molecules and, so forth, are involved in hemostasis, happen to be able to ligate viral determinants, making platelets capable of either binding viruses or even to be infected by some of them. Further, as platelets express both Fc-receptors for Ig and complement receptors, they also bind occasionally virus-Ig or virus-Ig-complement immune complexes. Interplays of viruses with platelets are very complex and viral infections often interfere with platelet number and functions. Through a few instances of viral infections, the present review aims at presenting some of the most important interactions from pathophysiological and clinical points of view, which are observed between human viruses and platelets.