Integrated analysis of long-term safety in patients with chronic immune thrombocytopaenia (ITP) treated with the thrombopoietin (TPO) receptor agonist romiplostim

Desialylation and Apoptosis in Immune Thrombocytopenia: Implications for Pathogenesis and Treatment

Immune thrombocytopenia (ITP) is an autoimmune disease in which platelet autoantibodies play a significant role in its pathogenesis. Regulatory T cell dysfunction and T cell-mediated cytotoxicity also contribute to thrombocytopenia. Current therapies are directed towards immune suppression and modulation as well as stimulation of platelet production with thrombopoietin receptor agonists. Additional mechanisms of the pathogenesis of ITP have been suggested by recent experimental data. One of these processes, known as desialylation, involves antibody-induced removal of terminal sialic acid residues on platelet surface glycoproteins, leading to hepatic platelet uptake and thrombocytopenia. Apoptosis, or programmed platelet death, may also contribute to the pathogenesis of ITP. The extent of the impact of desialylation and apoptosis on ITP, the relative proportion of patients affected, and the role of antibody specificity are still the subject of investigation. This review will discuss both historical and new evidence of the influence of desialylation and apoptosis in the pathogenesis of ITP, with an emphasis on the clinical implications of these developments. Further understanding of both platelet desialylation and apoptosis might change current clinical practice and improve patient outcomes.

Interleukin (IL)-1B and IL-1 receptor antagonist gene polymorphisms in children with primary immune thrombocytopenia

Background

The pathophysiology and susceptibility of children to primary immune thrombocytopenia (ITP) are linked to polymorphisms of the interleukin (IL)-1B and IL-1 receptor (IL-1R) antagonist genes.

PURPOSE

To investigate the association between the susceptibility and severity of primary ITP in children and the IL-1B and IL-1R antagonist gene polymorphisms.

METHODS

This comparative case-control study was conducted at the Menoufia University Hospital Hematology and Oncology Unit, Pediatric Department, between August 2022 and September 2023. The children were divided into patients (28 boys, 22 girls) who received hospital and outpatient clinic care and controls (50 healthy age- and sex-matched children).

RESULTS

The mutant homozygous GG genotype and mutant G allele of rs16944 of the IL1B gene were considerably greater in patients than in controls (P<0.001). Furthermore, the mutant homozygous II/II genotype and heterozygous I/II genotype of the IL-1R antagonist gene were considerably greater in the case versus control group. The mutant II allele was significantly more prevalent in patients versus controls (P<0.001).

CONCLUSION

IL-1B and IL-1R antagonists may have a major impact on the development of immune thrombocytopenia. Furthermore, we found a relationship between IL-1B and IL-1R antagonist gene polymorphisms and the etiology of and children's susceptibility to primary immune thrombocytopenia.

Real-world use of thrombopoietin receptor agonists for the management of immune thrombocytopenia in adult patients in the United Kingdom: Results from the TRAIT study

Few studies have reported the real-world use of both romiplostim and eltrombopag in immune thrombocytopenia (ITP). TRAIT was a retrospective observational study aimed to evaluate the platelet responses and adverse effects associated with the use of these thrombopoietin receptor agonists (TPO-RAs) in adult patients with ITP in the United Kingdom. Of 267 patients (median age at diagnosis, 48 years) with ITP (primary ITP [n = 218], secondary ITP [n = 49]) included in the study, 112 (42%) received eltrombopag and 155 (58%) received romiplostim as the first prescribed TPO-RA. A platelet count ≥30 × 109/L was achieved in 89% of patients with the first TPO-RA treatments, while 68% achieved a platelet count ≥100 × 109/L. Treatment-free response (TFR; platelet count ≥30 × 109/L, 3 months after discontinuing treatment) was achieved by 18% of the total patients. Overall, 61 patients (23%) switched TPO-RAs, most of whom achieved platelet counts ≥30 × 109/L with the second TPO-RA (23/25 who switched from eltrombopag to romiplostim [92%]; 28/36 who switched from romiplostim to eltrombopag [78%]). TFR was associated with secondary ITP, early TPO-RA initiation after diagnosis, the presence of comorbidity and no prior splenectomy or treatment with steroids or mycophenolate mofetil. Both TPO-RAs had similar efficacy and safety profiles to those reported in clinical studies.

Thrombopoietin Receptor Agonists and Other Second-Line Therapies for Immune Thrombocytopenia: A Narrative Review With a Focus on Drug Access in Canada

INTRODUCTION

Immune thrombocytopenia (ITP) is an autoimmune disease characterized by low platelet counts and increased risk of bleeding. After corticosteroids with or without intravenous immune globulin (first-line treatment), second-line treatment options include rituximab, splenectomy, thrombopoietin receptor agonists (TPO-RAs), and fostamatinib. In Canada, the choice of second-line therapy is influenced by access to medications. The goals of this narrative review are to 1) summarize the evidence for the use of TPO-RAs and other second-line therapies in ITP and 2) highlight differences in public funding criteria for TPO-RAs across provinces and territories in Canada.

METHODS

We conducted a literature review of second-line therapies for ITP. We solicited information on public funding programs for TPO-RAs in Canada from health care providers, pharmacists, and provincial ministries of health.

RESULTS

Head-to-head trials involving TPO-RAs, rituximab, splenectomy, and fostamatinib are lacking. There is substantial evidence of effect for TPO-RAs in improving platelet count levels, health-related quality of life, bleeding, and fatigue from placebo-controlled trials and observational studies; however, access to TPO-RAs through provincial funding programs in Canada is variable. Splenectomy failure is a prerequisite for the funding of TPO-RAs in Ontario, Manitoba, and Saskatchewan, but not in Alberta or Quebec. Other provinces either do not have access to public funding or funding is provided on a case-by-case basis.

DISCUSSION

TPO-RAs are effective second-line therapies for the treatment of ITP; however, access is variable across Canada, which results in health disparities and poor uptake of international treatment guidelines.

Thrombopoietin-receptor agonists for adult patients with immune thrombocytopenia: a narrative review and an approach for managing patients fasting intermittently

Introduction

Thrombopoietin-receptor agonist (TPO-RAs) currently represent the state of art for treating immune thrombocytopenia. Their different molecular structures contribute to the difference in their pharmacodynamics and pharmacokinetics. This narrative review aims to provide an overview of the current TPO-RAs approved for primary immune thrombocytopenia (romiplostim, eltrombopag, avatrombopag) and the effect of intermittent fasting in adult patients receiving TPO-RAs.

Areas covered

Literature was searched with no limits on date or language, using various combinations of keywords. Data on the pharmacokinetics, pharmacodynamics, efficacy, and safety of TPO-RAs and the effect of intermittent fasting were summarized.

Expert opinion

Switching between TPO-RAs is a useful strategy to tackle some associated limitations. Romiplostim and avatrombopag have an advantage over eltrombopag as they do not require any dietary restrictions. In cases where romiplostim and avatrombopag are unavailable, patients should be educated on the appropriate administration, possible interactions, and dietary restrictions before initiating eltrombopag.

Primary and secondary immune thrombocytopenia (ITP): Time for a rethink

There are not many publications that provide a holistic view of the management of primary and secondary ITP as a whole, reflecting the similarities and differences between the two. Given the lack of major clinical trials, we believe that comprehensive reviews are much needed to guide the diagnosis and treatment of ITP today. Therefore, our review addresses the contemporary diagnosis and treatment of ITP in adult patients. With respect to primary ITP we especially focus on establishing the management of ITP based on the different and successive lines of treatment. Life-threatening situations, "bridge therapy" to surgery or invasive procedures and refractory ITP are also comprehensively reviewed here. Secondary ITP is studied according to its pathogenesis by establishing three major differential groups: Immune Thrombocytopenia due to Central Defects, Immune Thrombocytopenia due to Blocked Differentiation and Immune Thrombocytopenia due to Defective Peripheral Immune Response. Here we provide an up-to-date snapshot of the current diagnosis and treatment of ITP, including a special interest in addressing rare causes of this disease in our daily clinical practice. The target population of this review is adult patients only and the target audience is medical professionals.

Romiplostim in primary immune thrombocytopenia that is persistent or chronic: phase III multicenter, randomized, placebo-controlled clinical trial in China

Background

Multiple trials have confirmed that romiplostim could increase platelet count in individuals with primary immune thrombocytopenia (ITP), but no related study has assessed Chinese patients.

Objectives

To assess the effectiveness of romiplostim as a second-line treatment of persistent or chronic ITP in Chinese adults.

Methods

This phase III multicenter, randomized, placebo-controlled, double-blind, then open-label clinical trial (NCT02868099, CTR20150395) was conducted at 28 investigational sites in China. The patients were randomly assigned (3:1) to romiplostim (starting and maximum doses of 1 and 10 μg/kg, respectively) or placebo for 9 weeks (double-blind period), followed by the open-label period (both groups administered romiplostim) to week 22. The primary endpoint was the time (in weeks) during which platelet counts were ≥50 × 109/L in the double-blind period.

Results

In this study, 202 patients (romiplostim, n = 151; placebo, n = 51) started the treatment. The median (range) numbers of weeks with platelet response after 6 weeks of treatment were 2 (0-6) and 0 (0-2) in patients administered romiplostim and placebo, respectively (P < .001). During the double-blind period, the proportions of patients with treatment-emergent adverse events were comparable between the romiplostim and placebo groups (82.8% vs 82.4%). The treatment-emergent adverse event with ≥10% difference in incidence between these 2 groups was injection site bleeding (1.3% vs 11.8%).

Conclusion

Romiplostim significantly increased the time with maintained platelet response in patients with persistent or chronic ITP in comparison with placebo. No new safety signal was observed.

Trial registration

ClinicalTrials.gov, NCT02868099. www.chinadrugtrials.org.cn/clinicaltrials.searchlist.dhtml, CTR20150395.

Safety of romiplostim and eltrombopag for children with immune thrombocytopenia: a pharmacovigilance study of the FDA adverse event reporting system database

BACKGROUND

Romiplostim and eltrombopag are thrombopoietin receptor agonists (TPORAs) that have been approved by the FDA on 22 August 2008 and 20 November 2008 for pediatric immune thrombocytopenia (ITP). However, postmarketing pharmacovigilance of TPORAs in children still attracts much attention. We aimed to evaluate the safety of the TPORAs romiplostim and eltrombopag using data from the Adverse Event Reporting System database of FDA (FAERS).

RESEARCH DESIGN AND METHODS

We conducted a disproportionality analysis and analyzed data from the FAERS database to characterize the key features of adverse events (AEs) associated with TPO-RAs approved for children under 18 years of age.

RESULTS

Since their approval in the market in 2008, 250 and 298 reports of romiplostim and eltrombopag use in children have been published in the FAERS database, respectively. The most frequent AE associated with romiplostim and eltrombopag was epistaxis. Neutralizing antibodies and vitreous opacities showed the strongest signals for romiplostim and eltrombopag, respectively.

CONCLUSIONS

The labeled AEs for romiplostim and eltrombopag in children were analyzed. Unlabeled AEs may reflect the potential of new clinical individuals. Early recognition and management of AEs that appear in children treated with romiplostim and eltrombopag are of key importance in clinical practice.

The Outcomes and Adverse Drug Patterns of Immunomodulators and Thrombopoietin Receptor Agonists in Primary Immune Thrombocytopenia Egyptian Patients with Hemorrhage Comorbidity

Immune thrombocytopenia (ITP) treatment has evolved recently. However, none of the treatments have only benefits without drawbacks. This study aimed to compare the clinical outcomes and adverse drug patterns of Eltrombopag, Romiplostim, Prednisolone + Azathioprine, High Dose-dexamethasone (HD-DXM) (control group), and Rituximab in primary ITP Egyptian patients. All patients were initiated with corticosteroids, HD-DXM, as a first-line treatment for the first month immediately following diagnosis. Four hundred sixty-seven ITP patients were randomly assigned to five groups. The outcome measures were judged at baseline, at the end of treatment (6 months), and after an additional 6-month free treatment period. The follow-up period for which relapse is noted was 6 months after the end of treatment. Eltrombopag and Romiplostim resulted in a significantly higher incidence of sustained response than Rituximab, HD-DXM, and Prednisolone + Azathioprine (55.2% and 50.6% vs. 29.2%, 29.1%, and 18%, respectively; p-value < 0.001). More patients on immunomodulators (Prednisolone+ Azathioprine, HD-DXM, and Rituximab) relapsed than those on Romiplostim and Eltrombopag (81.9%, 70.8%, and 70.7% vs. 49.3%, and 44.7%, respectively; p-value < 0.01). We also describe 23 reports of pulmonary hypertension with Prednisolone+ Azathioprine and 13 reports with HD-DXM. The thrombotic events occurred in 16.6% and 13% of patients who received Eltrombopag and Romiplostim treatment, respectively. Most patients had at least one or two risk factors (92.8% of cases). Corticosteroids are effective first-line therapy in primary ITP patients. However, relapse is frequent. Eltrombopag and Romiplostim are safer and more effective than Prednisolone, HD-DXM, and Rituximab. They might be reasonable beneficial options after a one-month HD-DXM regimen.

Sovleplenib (HMPL-523), a novel Syk inhibitor, for patients with primary immune thrombocytopenia in China: a randomised, double-blind, placebo-controlled, phase 1b/2 study

BACKGROUND

Spleen tyrosine kinase (Syk) inhibitor is a treatment option for primary immune thrombocytopenia. We aimed to evaluate the safety, tolerability, pharmacokinetics, preliminary activity, and recommended phase 2 dose of sovleplenib in patients with primary immune thrombocytopenia.

METHODS

This randomised, double-blind, placebo-controlled, phase 1b/2 study was conducted at nine hospitals in China. Eligible patients were aged 18-75 years, had an ECOG performance score of 0-1, had primary immune thrombocytopenia for more than 6 months, and did not respond or relapsed after previous first-line treatment or had poor response or postoperative relapse after a splenectomy. Dose-escalation (100 mg, 200 mg, or 300 mg given orally once a day) and dose-expansion phases (recommended phase 2 dose) each consisted of an 8-week, double-blind, placebo-controlled period in which patients were randomly assigned (3:1) to receive sovleplenib or placebo with an interactive web response system followed by a 16-week, open-label period with sovleplenib. Patients, investigators, and the sponsor were masked to treatment allocation during the first 8 weeks. The main efficacy endpoint was the proportion of patients whose platelet count reached 30 × 10⁹ platelets per L or higher and was double of the baseline at two consecutive visits during 0-8 weeks without rescue therapy. Efficacy was evaluated by intention-to-treat. This study is registered with ClinicalTrials.gov, NCT03951623.

FINDINGS

Between May 30, 2019, and April 22, 2021, 62 patients were assessed for eligibility and 45 (73%) were randomly assigned. Patients received at least one dose of the study drug during the 8-week double-blind period (placebo [n=11] and sovleplenib 100 mg [n=6], 200 mg [n=6], 300 mg [n=16], and 400 mg [n=6]; this group was added following the observation of no protocol-specified safety events at the previous doses). All participants were Asian; 18 (40%) of 45 were male and 27 (60%) were female. The median age was 40·0 years (IQR 33·0-50·0). Ten (29%) of 34 patients in sovleplenib groups versus five (45%) of 11 in the placebo group received concomitant anti-primary immune thrombocytopenia therapy. The recommended phase 2 dose was determined as 300 mg once a day. The proportion of patients who met the main efficacy endpoint were three (50%; 95% CI 12-88) in the 100 mg group, three (50%; 12-88) in the 200 mg group, ten (63%; 35-85) in the 300 mg group, and two (33%; 4-78) in the 400 mg group compared with one (9%; 0-41) in the placebo group. The overall response rate in the 300 mg group was 80% (16 of 20 who received continuous sovleplenib plus those who crossed over from placebo) and the durable response rate was 31% (11-59; five of 16) in the continuous sovleplenib 300 mg and 75% (19-99; three of four) crossed from placebo to sovleplenib during 0-24 weeks. During the 28-day safety evaluation period, two grade 2 or worse treatment-related treatment-emergent adverse events occurred in the sovleplenib groups (hypertriglyceridaemia and anaemia). During 0-8 weeks, the most frequent treatment-emergent adverse events were an increase in blood lactate dehydrogenase, haematuria, and urinary tract infection (seven [21%] of 34 in sovleplenib groups vs one [9%] of 11 in the placebo group); and occult blood-positive and hyperuricaemia (four [12%] vs three [27%] for each). No fatal treatment-emergent adverse events were recorded.

INTERPRETATION

Sovleplenib was well tolerated, and the recommended phase 2 dose showed a promising durable response in patients with primary immune thrombocytopenia, which provides evidence for future investigations. A phase 3 trial is ongoing (NCT05029635) to confirm the efficacy and safety of sovleplenib in patients with primary immune thrombocytopenia.

FUNDING

HUTCHMED.

Combination of two target agonists of the thrombopoietin and thrombopoietin receptor in the treatment of elderly patients with refractory immune thrombocytopenia

Immune thrombocytopenia (ITP) is common in the elderly. Because of the coexistence of multiple diseases, there are many reservations regarding corticosteroid use in the elderly. Thrombopoietin (TPO) and its analogs can promote platelet production, but it is often difficult to correct TP in a short period. Recombinant human TPO (rh-TPO) acting on the cell membrane and the small-molecule TPO-receptor (MPL) agonist acting on the transmembrane receptor may have synergistic effects and accelerate platelet production because of different sites of action in the signaling pathway. In this study, two elderly patients with refractory ITP were successfully treated with two TPO-MPL signaling pathway agonists: recombinant human thrombopoietin (rh-TPO) and eltrombopag. This combination is safe with rapid and lasting effects. However, in elderly patients with refractory, recurrent, and glucocorticoid contraindications, the combination of different TPO agonists' clinical efficacy and adverse reactions needs to be further evaluated.

A bibliometric analysis of primary immune thrombocytopenia from 2011 to 2021

Primary immune thrombocytopenia (ITP) is an autoimmune disorder characterized by isolated thrombocytopenia. This bibliometric analysis was applied to identify the characteristics of global scientific output, the hotspots, and frontiers of ITP over the past 10 years. We retrieved publications from 2011 to 2021 from the Web of Science Core Collection (WoSCC). Bibliometrix package, VOSviewer, and Citespace were used to analyse and visualize the trend, distribution, and hotspots of research on ITP. Altogether, there were 2084 papers, written by 9080 authors from 410 organizations in 70 countries/regions, published in 456 journals with 37 160 co-cited references. In the last decades, the most productive journal was British Journal of Haematology, China was the most productive country. and the most cited journal was Blood. Shandong University was the most productive institution in the field of ITP. NEUNERT C, 2011, BLOOD, CHENG G, 2011, LANCET, and PATEL VL, 2012, BLOOD were the top three most cited documents. "Thrombopoietin receptor agonist", "regulatory T cell" and "sialic acid" were three hotspots of the last decade. And "immature platelet fraction", "Th17", and "fostamatinib" would be research frontiers in the feature. The present study provided a novel insight for future research directions and scientific decision-making.

Current approaches for the diagnosis and management of immune thrombocytopenia

Immune thrombocytopenia (ITP), is an acquired autoimmune disorder characterized by the destruction of platelets and megakaryocytes, resulting in thrombocytopenia (platelet count <100 × 10⁹/L). This review focuses on the diagnosis and current management of ITP. The diagnosis of ITP is based principally on the exclusion of other causes of isolated thrombocytopenia using patient history, physical examination, blood count, and evaluation of the peripheral blood film. The clinical treatment goals should be to resolve bleeding events and to prevent severe bleeding episodes. The platelet count should be improved to attain a minimum of > 20-30 × 10⁹/L. Therapy should be given as an inpatient in newly diagnosed ITP with a platelet count of > 20 × 10⁹/L or if there is active bleeding. Corticosteroids are considered the standard initial treatment for newly diagnosed patients. Subsequent medical therapies with robust evidence include thrombopoietin receptor agonists (TPO-RAs), rituximab and fostamatinib. Surgical therapy with splenectomy may be considered for patients failing medical therapy. The choice between therapy options is highly dependent upon patient values and preferences.

Chemically modified in-vitro-transcribed mRNA encoding thrombopoietin stimulates thrombopoiesis in mice

The use of messenger RNA (mRNA) enables the transient production of therapeutic proteins with stable and predictable translational kinetics and without the risk of insertional mutagenesis. Recent findings highlight the enormous potential of mRNA-based therapeutics. Here, we describe the synthesis of chemically modified thrombopoietin (TPO) mRNA through in vitro transcription and in vivo delivery via lipid nanoparticles (LNPs). After delivery of TPO mRNA in mice, compared with normal physiological values, plasma TPO protein levels increased over 1000-fold in a dose-dependent manner. Moreover, through a single intravenous dose of TPO mRNA-loaded LNPs, both reticulated and total platelet count increased significantly in mice, demonstrating that TPO protein derived from the exogenous mRNA was able to maintain normal activity. Submicrogram quantity of N1-methylpseudouridine-modified TPO mRNA showed a similar effect in promoting thrombopoiesis as that by the TPO receptor agonist romiplostim. In addition, a therapeutic value was established in anti-GPIbα (CD42b) antibody-induced thrombocytopenia mouse models that showed a fast recovery of platelet count. Our study demonstrated chemically modified in-vitro-transcribed TPO mRNA as a potentially safe therapeutic intervention to stimulate thrombopoiesis.

Novel Therapies to Address Unmet Needs in ITP

Primary immune thrombocytopenia (ITP) is an autoimmune disorder that causes low platelet counts and subsequent bleeding risk. Although current corticosteroid-based ITP therapies are able to improve platelet counts, up to 70% of subjects with an ITP diagnosis do not achieve a sustained clinical response in the absence of treatment, thus requiring a second-line therapy option as well as additional care to prevent bleeding. Less than 40% of patients treated with thrombopoietin analogs, 60% of those treated with splenectomy, and 20% or fewer of those treated with rituximab or fostamatinib reach sustained remission in the absence of treatment. Therefore, optimizing therapeutic options for ITP management is mandatory. The pathophysiology of ITP is complex and involves several mechanisms that are apparently unrelated. These include the clearance of autoantibody-coated platelets by splenic macrophages or by the complement system, hepatic desialylated platelet destruction, and the inhibition of platelet production from megakaryocytes. The number of pathways involved may challenge treatment, but, at the same time, offer the possibility of unveiling a variety of new targets as the knowledge of the involved mechanisms progresses. The aim of this work, after revising the limitations of the current treatments, is to perform a thorough review of the mechanisms of action, pharmacokinetics/pharmacodynamics, efficacy, safety, and development stage of the novel ITP therapies under investigation. Hopefully, several of the options included herein may allow us to personalize ITP management according to the needs of each patient in the near future.

Experts' review: the emerging roles of romiplostim in immune thrombocytopenia (ITP)

INTRODUCTION

The management of ITP has in recent years been transformed from reliance on immunosuppressants and splenectomy to targeted therapy with thrombopoietin receptor agonists (TPO-RA) that directly stimulate platelet production in the bone marrow. This has reduced the long-term infective complications and toxicities associated with the use of potent immunosuppressants and splenectomy. The welltolerated romiplostim, itself a novel drug construct called peptibody, has established itself, alongside other TPO-RA as the preferred 2nd line therapy in major international guidelines on treatment of ITP.

AREAS COVERED

This review summarizes the data from early licensing trials of romiplostim and discusses the real-world experience to date, the unexpected emerging data on treatment-free long-term remission achieved using TPO-RA, and the case for its early introduction in the therapeutic pathway. The emerging risk of thrombosis is also discussed.

EXPERT OPINION

The use of romiplostim and other TPO-RA will be increasingly brought forward in the management pathway of ITP with the prospect of modifying the long-term outcome of the disease by increasing sustained treatment-free remission. With the prospect of several new targeted therapies been introduced into clinical practice, TPO-RA will likely be a key component of future combination therapies for difficult cases.

Cost-minimization analysis comparing eltrombopag vs romiplostim for adults with chronic immune thrombocytopenia

BACKGROUND: Promacta (eltrombopag; EPAG) and Nplate (romiplostim; ROMI) have not been compared in head-to-head trials for treatment of chronic immune thrombocytopenia (cITP); however, indirect treatment comparisons have indicated similar efficacy and safety outcomes, and the drugs are generally accepted as therapeutic alternatives. OBJECTIVE: To determine which of the 2 therapies would result in the lowest overall cost from a US health plan perspective, under the assumption of equivalent clinical efficacy and safety. METHODS: A cost-minimization model was developed in Microsoft Excel. The model incorporated only costs that differ between the treatments, including drug acquisition, administration, and monitoring costs, over a 52-week horizon. Average dosing for EPAG and ROMI was taken from the long-term EXTEND trial and from a published metaanalysis of 14 clinical trials, respectively. ROMI is injectable and EPAG is oral, so only ROMI had administration costs. The model assumed patients used 25 mg EPAG tablets and the 250 μg vial size of ROMI. ROMI wastage was included in drug acquisition costs by rounding up average dose to the nearest whole vial. Monitoring requirements were determined from US prescribing information, with platelet monitoring assumed equal, and hepatic panel testing every 4 weeks for EPAG. The model was adjustable to commercial, Medicare, and Medicaid plan perspectives, with optional inclusion of drug wastage, monitoring, or administration costs. RESULTS: The base case used a commercial plan perspective, with average dosing of 51.5 mg/day for EPAG and 4.20 μg/kg/week for ROMI. The analysis found a cost difference per treated patient of $64,770 in favor of EPAG on an annual basis. Breakdown by unique costs for EPAG included drug-acquisition cost of $123,135 and monitoring cost of $705. Breakdown by unique costs for ROMI included drug-acquisition cost of $183,234, with wastage of $63,179 and administration cost of $5,377. Based on a hypothetical commercial plan with 1 million members and an estimated 11 patients with cITP receiving ROMI, potential annual savings for switching all patients from ROMI to EPAG is $712,473 or $0.06 per member per month. EPAG remained the less costly option for all plan types and assumptions. A sensitivity analysis found that the result was most sensitive to drug pricing and wastage inputs. CONCLUSIONS: Because of lower drug-acquisition costs (including drug wastage) and administration costs, treatment of cITP with EPAG is associated with a lower net cost per patient than ROMI. DISCLOSURES This study was funded by Novartis Pharmaceuticals Corporation. Proudman, Lucas, and Nellesen are employees of Analysis Group, Inc., which received funding from Novartis Pharmaceuticals Corporation to conduct this study. Patwardhan was employed by Novartis Pharmaceuticals Corporation at the time of this study; Allen is an employee of Novartis. This research was presented as an e-poster at the AMCP 2020 Virtual, April 2020.

Thrombopoietin Receptor Agonists (TPO-RAs): Drug Class Considerations for Pharmacists

The thrombopoietin receptor agonists (TPO-RAs) romiplostim, eltrombopag, avatrombopag, and lusutrombopag carry unique US Food and Drug Administration (US FDA)- and European Medicines Agency (EMA)-approved indications and may be used to increase platelet counts in a variety of conditions. Current indications for available TPO-RAs include treatment of chronic immune thrombocytopenia (ITP) in cases of insufficient response to prior treatment (avatrombopag, eltrombopag, romiplostim), management of thrombocytopenia in adult patients with chronic liver disease who are scheduled to undergo a procedure (avatrombopag, lusutrombopag), management of severe aplastic anemia (eltrombopag), and management of thrombocytopenia associated with interferon-based therapy for hepatitis C (eltrombopag). Across current indications, pharmacists can assist in stabilizing platelet counts and help to reduce large undulations commonly seen when starting, stopping, or transitioning between these agents. If therapy modifications may benefit the patient, pharmacists should discuss possible changes with the patient's treatment team or treating physician. When used for ITP, romiplostim, eltrombopag, and avatrombopag stimulate TPO receptors on hematopoietic stem cells (also known as c-Mpl, or CD110) to promote platelet production; however, romiplostim is the only TPO-RA that binds at the same site as endogenous TPO. These subtle mechanistic differences may explain why switching TPO-RA may be clinically advantageous in some situations. As pharmacists are called to counsel patients on TPO-RA use, a deep understanding of potential adverse events and management strategies, as well as appropriate monitoring, will increase the likelihood that patients meet their goals of therapy in the shortest timeframe. Other uses of TPO-RAs are also discussed in this review, including use following hematopoietic stem cell transplant, use in myelodysplastic syndrome, and use in chemotherapy-induced thrombocytopenia.

A Review of Romiplostim Mechanism of Action and Clinical Applicability

Thrombocytopenia results from a variety of conditions, including radiation, chemotherapy, autoimmune disease, bone marrow disorders, pathologic conditions associated with surgical procedures, hematopoietic stem cell transplant (HSCT), and hematologic disorders associated with severe aplastic anemia. Immune thrombocytopenia (ITP) is caused by immune reactions that accelerate destruction and reduce production of platelets. Thrombopoietin (TPO) is a critical component of platelet production pathways, and TPO receptor agonists (TPO-RAs) are important for the management of ITP by increasing platelet production and reducing the need for other treatments. Romiplostim is a TPO-RA approved for use in patients with ITP in the United States, European Union, Australia, and several countries in Africa and Asia, as well as for use in patients with refractory aplastic anemia in Japan and Korea. Romiplostim binds to and activates the TPO receptor on megakaryocyte precursors, thus promoting cell proliferation and viability, resulting in increased platelet production. Through this mechanism, romiplostim reduces the need for other treatments and decreases bleeding events in patients with thrombocytopenia. In addition to its efficacy in ITP, studies have shown that romiplostim is effective in improving platelet counts in various settings, thereby highlighting the versatility of romiplostim. The efficacy of romiplostim in such disorders is currently under investigation. Here, we review the structure, mechanism, pharmacokinetics, and pharmacodynamics of romiplostim. We also summarize the clinical evidence supporting its use in ITP and other disorders that involve thrombocytopenia, including chemotherapy-induced thrombocytopenia, aplastic anemia, acute radiation syndrome, perisurgical thrombocytopenia, post-HSCT thrombocytopenia, and liver disease.

Clinical overview and practical considerations for optimizing romiplostim therapy in patients with immune thrombocytopenia

The fundamental treatment goal for patients with immune thrombocytopenia (ITP) is reduced or ameliorated bleeding. Although various treatment options exist for the management of ITP, recent advances have led to the approval of three thrombopoietin receptor agonists (TPO-RAs; romiplostim, eltrombopag, and avatrombopag) in the United States and European Union. Current treatment guidelines for ITP indicate that medical therapy is preferred over surgical therapy and support the use of TPO-RAs as early as 3 months after disease onset. More recent data are available on the use of romiplostim in patients who have had ITP for <1 year, and romiplostim is now indicated for the treatment of adults who have not responded adequately to initial treatment, as well as children aged ≥1 year who have had ITP for ≥6 months. Here we review the role of romiplostim in the management of ITP, with a focus on efficacy and safety data, emerging data on early use (beginning within 3 months of disease onset) and treatment-free remission, and practical considerations for optimal management of ITP.

iTRAQ-based quantitative proteomics analysis of immune thrombocytopenia patients before and after Qishunbaolier treatment

RATIONALE

Treatment of immune thrombocytopenia (ITP) usually involves long-term use of immunosuppressive corticosteroids and splenectomy. However, these treatments often have side effects in patients. The Mongolian medicine Qishunbaolier (QSBLE) has a high curative effect, reduces the chances of relapse, and has no obvious side effects. This study was designed to identify potential therapeutic targets of QSBLE for treating ITP.

METHODS

To reveal differences in protein expression between ITP patients (ITPs) before and after QSBLE treatment, comparative proteomics studies were performed using isobaric tags for relative and absolute quantification (iTRAQ). The analysis used nanospray liquid chromatography/tandem mass spectrometry (nano-LC/MS/MS) in positive ion electrospray ionization mode. Key proteins relevant to ITP were revealed by the Kyoto Encyclopedia of Genes and Genomes (KEGG) and other bioinformatics tools. Real-time polymerase chain reaction (RT-PCR) analysis was carried out for confirmation of differentially expressed proteins.

RESULTS

A total of 982 differentially expressed proteins were identified in ITPs compared with the controls. Compared with the pre-QSBLE treatment group, 61 differentially expressed proteins were identified in the post-QSBLE treatment group, with 48 proteins being significantly upregulated and 13 downregulated. Twenty-nine pathways were significantly enriched. Q6N030 and other proteins were the key players in the protein-pathway network. Twenty proteins that may play important roles in the treatment of ITP were further filtered. RT-PCR and Western blot analyses further confirmed that MIF, PGK1 and IGHM were upregulated in ITPs after QSBLE treatment, in accordance with the proteomics data.

CONCLUSIONS

It is believed that the identified proteins and the results of bioinformatics analysis will provide a potential therapeutic target site for QSBLE for ITP therapy and biomarkers.

Evolving treatment modalities for immune thrombocytopenia in adults

The management of patients with relapsed or refractory immune thrombocytopenia (ITP) remains challenging for hematologists. While there are a multitude of drugs available, it is largely an individualized management based on patient preferences, side effects, previous treatment received, and responses to them, comorbidities and cost associated with the treatment. We hereby review the newer approaches in the treatment of ITP.

Comparative Utilization and Efficacy of Thrombopoietin Receptor Agonists in Relapsed/Refractory Immune Thrombocytopenia

BACKGROUND

The thrombopoietin (TPO) agonists, eltrombopag and romiplostim, stimulate the production of platelets and offer an effective treatment option in relapsed/refractory immune thrombocytopenia (ITP). Recently published 2019 ITP guidelines recommend the TPO agonists as second-line therapy following corticosteroids; however, little data offer insights into comparative efficacy and tolerability.

STUDY QUESTION

Is there a difference in the efficacy between romiplostim and eltrombopag in relapsed/refractory ITP?

STUDY DESIGN

We conducted a single-center, retrospective chart review of patients with ITP treated with romiplostim or eltrombopag.

MEASURES AND OUTCOMES

The primary objective was a sustained platelet response, defined as platelets greater than 50,000/μL in more than 66% of clinic visits over a 6-month period. Secondary objectives sought to evaluate response to and tolerability of TPO agonists.

RESULTS

The study included 107 consecutive patients, 67 (63%) on romiplostim and 40 (37%) on eltrombopag. Previous corticosteroids and rituximab were used in 95% and 50% of patients, respectively. There was no difference identified in platelet responses between the TPO-RAs, 72% romiplostim versus 65% eltrombopag (P = 0.520). In addition, no differences were identified in secondary measures of response.

CONCLUSIONS

In our experience with romiplostim and eltrombopag for ITP, we did not identify a difference in the efficacy of these agents. Further larger and prospective evaluations should be considered.

Romiplostim in adults with newly diagnosed or persistent immune thrombocytopenia

Introduction: Three distinct phases are recognized in immune thrombocytopenia (ITP): newly diagnosed (≤3 months after diagnosis), persistent (>3-12 months after diagnosis), and chronic (>12 months). Several international guidelines/expert recommendations have been released in the past 2 years regarding the treatment of newly diagnosed/persistent ITP. Areas covered: Across the guidelines/expert recommendations, thrombopoietin receptor agonists (TPO-RAs), including romiplostim (the focus of this review), are recommended in newly diagnosed or persistent ITP for patients who fail to respond to corticosteroids or intravenous immunoglobulin (or where these are contraindicated). To identify data relating to romiplostim in adults with newly diagnosed or persistent ITP, we conducted a search of PubMed (with no time limit applied) and abstracts from 2019 EHA/ASH meetings using the term 'romiplostim.' Expert opinion: The findings from nine clinical trials, six real-world studies and ten case reports provide insight into the early use of romiplostim, which could help to reduce exposure to the adverse effects associated with prolonged corticosteroid use, as well as reduce the risk of severe bleeding. Additionally, given the durable responses observed in patients with newly diagnosed/persistent ITP, as well as the potential for treatment-free responses following discontinuation, romiplostim might help to avoid the need for subsequent treatment.

Hemostatic changes by thrombopoietin-receptor agonists in immune thrombocytopenia patients

Thrombopoietin receptor agonist (TPO-RA) treatment increases the thrombosis rate in immune thrombocytopenia (ITP). We hypothesize that TPO-RAs influence platelet function, global and secondary hemostasis and/or fibrinolysis. A systematic review was performed. If possible, data were compared between responders (relevant increase in platelet count), and non-responders. Twelve observational studies with 305 patients were included (responders (127/150 (85%))). There were indications that TPO-RA treatment enhanced platelet function, with respect to platelet-monocyte aggregates, soluble P-selectin, GPVI expression, and adhesion under flow. Studies addressing global and secondary hemostasis and fibrinolysis were scarce. Overall, no changes were found during TPO-RA treatment, apart from an accelerated clot formation and conflicting data on levels of plasminogen activator inhibitor (PAI)-1. The parameters that increased have previously been associated with thrombosis in other patient groups, and might contribute to the increased rate of thrombosis observed in TPO-RA-treated ITP patients.

Markers of autoimmunity in immune thrombocytopenia: prevalence and prognostic significance

Prior studies have demonstrated an increased prevalence of autoimmune markers in patients with immune thrombocytopenia (ITP). Clinical experience has suggested that there may be an association between autoimmune markers and poor outcomes in ITP, but current guidelines do not encourage routine testing in these patients. We retrospectively assessed the prevalence of autoimmune markers in adult patients with ITP from our institutional database and used multiple logistic regression analyses to test for an association between autoimmune marker positivity and thrombotic events or clinical remission. We also assessed whether positivity for common autoimmune markers was associated with positivity for platelet autoantibodies. There was a high rate of autoimmune marker positivity in this population, with antinuclear antibody (65%), antithyroid peroxidase antibody (31%), and direct antiglobulin (29%) the most commonly found. Antithyroid peroxidase antibody positivity was associated with a lower probability of remission (odds ratio [OR], 0.26; 95% confidence interval [CI], 0.09-0.79; P = .017). Lupus anticoagulant positivity was associated with a higher rate of thrombosis (OR, 8.92; 95% CI, 1.94-40.95; P = .005), and antinuclear antibody was strongly associated with thrombosis (P = .001). There was no relation between platelet autoantibody positivity and the presence of autoimmune markers. These results suggest that many patients with ITP have a state of immune dysregulation that extends beyond platelet autoantibodies and that certain autoimmune markers may be prognostically useful in this disorder.

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 Select Thrombocytopenias

Evaluating, diagnosing, and managing patients with consumptive thrombocytopenia is challenging because of the overlapping nature of many of the diseases that reduce platelet counts. Immune thrombocytopenia (and its variations), drug-induced immune thrombocytopenia, and heparin-induced thrombocytopenia result from autoimmune antibody-mediated destruction of platelets. Thrombotic thrombocytopenia (both congenital and acquired) and the hemolytic uremic syndromes (both typical and atypical) are thrombotic microangiopathies associated with platelet aggregation and consumption along with anemia and renal dysfunction. Rapid history taking, physical assessment, and laboratory evaluation are crucial to accurately managing patients with these disorders. Platelet-associated coagulopathies are infrequently encountered by most providers, and limited exposure to these types of patients, combined with the wide variety of treatment options for reversing bleeding or thrombotic sequelae, makes management difficult. This article reviews the pathophysiology, patient presentation, diagnostic testing, and specific management strategies and challenges of these thrombocytopenias.

Updated international consensus report on the investigation and management of primary immune thrombocytopenia

Over the last decade, there have been numerous developments and changes in treatment practices for the management of patients with immune thrombocytopenia (ITP). This article is an update of the International Consensus Report published in 2010. A critical review was performed to identify all relevant articles published between 2009 and 2018. An expert panel screened, reviewed, and graded the studies and formulated the updated consensus recommendations based on the new data. The final document provides consensus recommendations on the diagnosis and management of ITP in adults, during pregnancy, and in children, as well as quality-of-life considerations.

Romiplostim Treatment of Chemotherapy-Induced Thrombocytopenia

PURPOSE

Chemotherapy-induced thrombocytopenia (CIT) leads to delay or reduction in cancer treatment. There is no approved treatment.

METHODS

We conducted a phase II randomized trial of romiplostim versus untreated observation in patients with solid tumors with CIT. Before enrollment, patients had platelets less than 100,000/μL for at least 4 weeks, despite delay or dose reduction of chemotherapy. Patients received weekly titrated romiplostim with a target platelet count of 100,000/μL or more, or were monitored with usual care. The primary end point was correction of platelet count within 3 weeks. Twenty-three patients were treated in a randomization phase, and an additional 37 patients were treated in a single-arm, romiplostim phase. Resumption of chemotherapy without recurrent CIT was a secondary end point.

RESULTS

The mean platelet count at enrollment was 62,000/μL. In the randomization phase, 14 of 15 romiplostim-treated patients (93%) experienced correction of their platelet count within 3 weeks, compared with one of eight control patients (12.5%; P < .001). Including all romiplostim-treated patients (N = 52), the mean platelet count at 2 weeks of treatment was 141,000/μL. The mean platelet count in the eight observation patients at 3 weeks was 57,000/μL. Forty-four patients who achieved platelet correction with romiplostim resumed chemotherapy with weekly romiplostim. Only three patients (6.8%) experienced recurrent reduction or delay of chemotherapy because of isolated CIT.

CONCLUSION

This prospective trial evaluated treatment of CIT with romiplostim. Romiplostim is effective in correcting CIT, and maintenance allows for resumption of chemotherapy without recurrence of CIT in most patients.

Acquired amegakaryocytic thrombocytopenia as a rare cause of thrombocytopenia during pregnancy

A rare case of acquired amegakaryocytic thrombocytopenia (AATP) in a 35-year-old woman who presented with anaemia and thrombocytopenia at 22 weeks gestation. The first diagnostic impression was of an evolving aplastic anaemia; however, the patient was simultaneously diagnosed with severe vitamin B₁₂ deficiency in the setting of vegetarianism. Once the cyanocobalamin deficiency was corrected, a repeat bone marrow biopsy revealed an isolated depletion of megakaryocytes, which suggested the diagnosis of AATP. Supportive care was provided for her anaemia and thrombocytopenia and she delivered a healthy baby girl with a normal platelet count. The patient was subsequently started on romiplostim with steady improvement in her platelet counts. This rare AATP case presentation highlights the importance of a well-structured diagnostic approach to thrombocytopenia during pregnancy and supports the successful use of thrombopoietin agonists for the management of AATP.

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.

Romiplostim in adult patients with newly diagnosed or persistent immune thrombocytopenia (ITP) for up to 1 year and in those with chronic ITP for more than 1 year: a subgroup analysis of integrated data from completed romiplostim studies

The thrombopoietin receptor agonist romiplostim is approved for second-line use in chronic immune thrombocytopenia (ITP), but its effects in patients with ITP for ≤1 year are not well characterized. This analysis of pooled data from 9 studies included patients with ITP for ≤1 year (n = 311) or >1 year (n = 726) who failed first-line treatments and received romiplostim, placebo or standard of care. In subgroup analysis by ITP duration, patient incidences for platelet response at ≥75% of measurements were higher for romiplostim [ITP ≤1 year: 74% (204/277); ITP >1 year: 71% (450/634)] than for placebo/standard of care [ITP ≤1 year: 18% (6/34); ITP >1 year: 9% (8/92)]. Of patients with ≥9 months on study, 16% with ITP ≤1 year and 6% with ITP >1 year discontinued romiplostim and maintained platelet counts ≥50 × 109 /l for ≥6 months without ITP treatment (treatment-free remission). Independent of ITP duration, rates of serious adverse events and bleeding were lower with romiplostim than placebo/standard of care and thrombotic events occurred at similar rates. In this analysis, romiplostim and placebo/standard of care had similar safety profiles and romiplostim increased platelet counts in patients with either ITP ≤1 year or ITP >1 year, with more treatment-free remission in those with ITP ≤1 year.

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.

Thrombopoietin Receptor Agonists: Can These Be the Future Answer to the Deadly Thrombocytopenia in Dengue Fever?

Dengue is considered the most prevalent mosquito-borne viral disease worldwide and sometimes turns out to be life-threatening. Thrombocytopenia is frequently observed in mild and severe cases of dengue. Severe thrombocytopenia, with a platelet count much below the normal range and hemorrhagic manifestation, is considered a fatal consequence of dengue that needs proper and timely management. The development of the dengue vaccine is quite challenging due to the existence of four different serotypes of the virus. Currently, neither a specific antiviral therapy nor a vaccine is available, and the common treatment modalities include fluid replacement therapy and platelet transfusions. Besides dengue, thrombocytopenia is correlated with many other diseases, particularly immune thrombocytopenic purpura (ITP). Thrombopoietin receptor (TPO-R) agonist, which is responsible for increasing platelet count, is a novel treatment option for chronic ITP patients. At present, two TPO-R agonists - eltrombopag and romiplostim - approved by the US Food and Drug Administration (USFDA) have been successfully used for the treatment of chronic ITP and other thrombocytopenic conditions. However, to date, only a single case study reported the use of romiplostim to enhance the platelet count in a myeloma patient suffering from dengue-associated thrombocytopenia. The objective of this review is to propose to the medical fraternity to consider using these TPO-R agonists to treat dengue hemorrhagic patients with thrombocytopenia and to conduct relevant researches to find out the usefulness of these molecules. This review is completely based on hypotheses and articles showing the positive response with romiplostim in dengue after going through a web-based search on various search engines. Furthermore, this review highlights the need for good-quality, randomized controlled trials and meta-analyses to detect the safety and efficacy of romiplostim and eltrombopag therapy for patients suffering from dengue-related thrombocytopenia.

Fostamatinib for the treatment of chronic immune thrombocytopenia

Fostamatinib is a spleen tyrosine kinase inhibitor recently approved for the treatment of chronic immune thrombocytopenia (ITP) in patients without adequate response to at least 1 prior line of therapy. This article reviews fostmatinib's mechanism of action and its clinical safety and efficacy in 2 industry-sponsored multicenter phase 3 randomized controlled trials in North America, Australia, and Europe (FIT1 and FIT2). Cost comparisons are discussed as well as the role of fostamatinib in relation to other options for chronic ITP.

Systematic literature review of treatments used for adult immune thrombocytopenia in the second-line setting

Immune thrombocytopenia (ITP) is a rare platelet disorder that is often persistent or chronic in adults. Patient management is dependent upon physician judgment and patient preference, given both the rarity of the condition and a paucity of high-quality clinical trial evidence to inform practice guidelines. A systematic literature review was conducted to provide an up-to-date summary of studies evaluating the safety and efficacy/effectiveness of therapies used to treat adults with primary ITP in the second-line setting. Using comprehensive search strings, several medical research databases were queried. Final abstraction was performed on 186 articles. Most (75%) studies were observational in nature; nearly half were conducted in Europe. Splenectomy was the most commonly studied (n = 83, 47%), followed by rituximab (n = 49, 26%) and the thrombopoietin-receptor agonists (TPO-RAs) romiplostim (n = 34, 18%) and eltrombopag (n = 24, 13%). Twelve prospective, randomized controlled trials (RCTs) with a placebo or standard-of-care arm evaluating the safety and efficacy of either rituximab or a TPO-RA were identified and described in detail. These trials provide important information on the safety and efficacy of these treatments, and in the absence of head-to-head data, offer insights on how these therapies compare with one another in treating adult ITP in the second-line setting. This review confirms that for most second-line ITP treatment options, there remains a lack of rigorous evidence derived from RCTs, and for many treatments, there is limited evidence of any kind. The need for additional research to guide treatment choices in this setting and greater use of standardized ITP terminology are highlighted.

Management of immune thrombocytopenia in elderly patients

Despite the improvement in understanding its pathogenesis and the introduction of novel treatment options, the management of primary immune thrombocytopenia (ITP) still remains challenging. Considering its increased incidence with aging and prolonged life-expectancy, ITP is often diagnosed in elderly patients, a subset that deserves some special precautions. Ensure the diagnosis is a crucial step, and carefully attention must be given in excluding other causes of thrombocytopenia, especially among older people that frequently suffer from many comorbidities. When it comes to treatment decision, it is worth keeping into account that the elderly have an increased risk of bleeding, thrombosis and infections, that they often require many concomitant therapies, including antiplatelet or anticoagulant agents, and that treatment-related toxicities are often increased and sometimes more dangerous that the disease itself. There are not dedicated guidelines, and only few specific studies. Steroids with or without IVIG remain the first-line treatment. Splenectomy is less effective than in youngers and burdened by an increased thrombotic and infectious risk. Rituximab is a good option in non-immunocompromised patients, but long-term remissions are few. Eltrombopag and romiplostim have a good safety and efficacy profile, and have become a prominent drug in this subset, even if they are associated with a possible increased risk of thrombosis, and long-term toxicity is unknown. Other drugs, such as dapsone and danazol, have a well-known efficacy and safety profile, and still represent a valid option among elderly patients.

Platelet aggregation response in immune thrombocytopenia patients treated with romiplostim

The thrombopoietin receptor agonist romiplostim is used for the long-term treatment of chronic immune thrombocytopenia (ITP). ITP patients have an increased thrombotic risk, which could be exacerbated if romiplostim increased platelet hyperreactivity or caused spontaneous platelet aggregation. To investigate this possibility, this study examined platelet function in romiplostim-treated ITP patients and healthy subjects. Light transmission platelet aggregometry utilizing arachidonic acid, collagen, epinephrine, ristocetin, ADP, and saline (to assess spontaneous aggregation) was performed for each subject. In addition, the ADP AC₅₀ (ADP concentration that induced half-maximal aggregation) was determined for each patient as a sensitive measurement of altered platelet reactivity. Fifteen ITP patients and 7 healthy subjects entered the study. All ITP patients had active disease and were receiving weekly romiplostim as the sole ITP-directed therapy. Platelet aggregation in response to the strong agonists arachidonic acid, collagen, and ristocetin was not significantly different between ITP patients and healthy subjects (P = 0.2442, P = 0.0548, and P = 0.0879, respectively). Platelet aggregation in response to weak agonists was significantly reduced in ITP patients compared with that in healthy subjects: median (range) aggregation to ADP, 45% (15-84%) versus 89% (70-95%) (P = 0.0010), and epinephrine, 21% (1.6-90%) versus 88% (79-94%) (P = 0.0085). The median AC₅₀ of ADP was threefold higher in ITP patients versus that in healthy subjects (6.3 μM vs 2.1 μM) (P = 0.0049). Significant spontaneous aggregation was not observed in any patient. Platelets from romiplostim-treated ITP patients do not show evidence for spontaneous aggregation or hyperreactivity, but instead have a modestly reduced aggregation response to ADP and epinephrine.

A sticky situation: myocardial infarction in a young woman with immune thrombocytopenia on eltrombopag and a history of mediastinal radiation

More recent immune thrombocytopenia (ITP) treatment strategies enhance platelet production with the use of thrombopoietin receptor agonists (TPO-RA) such as eltrombopag. Patients receiving TPO-RA agents may be at an increased risk of thromboembolism, however the pathophysiology and common underlying risk factors are not well understood. We present the case of a young asplenic woman on eltrombopag for chronic ITP with acute myocardial infarction involving the right coronary artery. Past medical history was significant for remote mediastinal radiation for lymphoma and splenectomy for ITP. She had no other risk factors for coronary artery disease. She underwent coronary catheterization and balloon angioplasty to the culprit lesion, although stenting was deferred due to concerns with dual antiplatelet therapy. She was discharged from hospital on single antiplatelet therapy with acetylsalicylic acid. We believe that the patient's ITP, recent eltrombopag use, surgical asplenia and history of mediastinal radiation synergistically contributed to her myocardial infarction. The risks of bleeding and thromboembolism must be carefully weighed in patients receiving TPO-RA therapy.

Current and evolving treatment strategies in adult immune thrombocytopenia

Immune thrombocytopenia (ITP) is an acquired autoimmune phenomenon resulting in low platelet count and increased bleeding risk. Goals of upfront management include prompt control of severe bleeding-which is rare-as well as induction and maintenance of a hemostatic platelet count. Thus, optimal management of ITP patients is often challenging and requires a highly individualized approach. Many patients may not suffer significant bleeding despite severe thrombocytopenia and the risk of toxicity associated with treatment may outweigh its benefit. Most patients treated with standard first-line regimen of glucocorticoids achieve an initial response. However, the rate of long-term remission remains low and multiple lines of therapy are often required. Current investigations aim at defining the subgroup of patients at risk of relapse and providing intensified risk-balanced induction regimens to improve long-term disease control. This short review summarizes current and emerging treatment strategies in adult ITP.

A Case of Primary Refractory Immune Thrombocytopenia: Challenges in Choice of Therapies

The value of combination therapy for refractory ITP is not well defined. We present the case of a 29-year-old male with severe ITP refractory to initial standard therapy including steroids, IVIG, and subsequent splenectomy, who was treated with the combination therapy of rituximab, romiplostim, and mycophenolate and eventually developed thrombocytosis requiring plateletpheresis. Our case highlights the importance of the need to understand predictors of response to standard upfront treatment of acute ITP.

Leukemic mature B-cell neoplasm observed during the treatment with romiplostim in patient with thrombocytopenia and liver cirrhosis

We report here a new adverse event of romiplostim which is a protein analog of thrombopoietin. Leukemic mature B-cell neoplasm was observed during the treatment of thrombocytopenia in a patient with liver cirrhosis. Their relationship was suggested clinically but the mechanism of leukemic expansion of lymphoma cells was not clarified.

Chinese guidelines for treatment of adult primary immune thrombocytopenia

Primary immune thrombocytopenia (ITP) is a bleeding disorder commonly encountered in clinical practice. The International Working Group (IWG) on ITP has published several landmark papers on terminology, definitions, outcome criteria, bleeding assessment, diagnosis, and management of ITP. The Chinese consensus reports for diagnosis and management of adult ITP have been updated to the 4th edition. Based on current consensus positions and new emerging clinical evidence, the thrombosis and hemostasis group of the Chinese Society of Hematology issued Chinese guidelines for management of adult ITP, which aim to provide evidence-based recommendations for clinical decision making.