Treatment of immune thrombocytopenia in Australian adults: A multicenter retrospective observational study

Background

In Australia, prescribing restrictions limit access to internationally recommended second-line therapies such as rituximab and thrombopoietin agonists (TPO-A) (eltrombopag and romiplostim). Subsequent lines of therapy include an array of immunosuppressive and immune-modulating agents directed by drug availability and physician and patient preference.

Objectives

The objective of the study was to describe the use of first and subsequent lines of treatment for adult immune thrombocytopenia (ITP) in Australia and to assess their effectiveness and tolerability.

Patients/Methods

A retrospective review of medical records was conducted of 322 patients treated for ITP at eight participating centers in Australia between 2013 and 2020. Data were analyzed by descriptive statistics and frequency distribution using pivot tables, and comparisons between centers were assessed using paired t tests.

Results

Mean age at diagnosis of ITP was 48.8 years (standard deviation [SD], 22.6) and 58.3% were women. Primary ITP was observed in 72% and secondary ITP in 28% of the patients; 95% of patients received first-line treatment with prednisolone (76%), dexamethasone (15%), or intravenous immunoglobulin (48%) alone or in combination. Individuals with secondary ITP were less steroid dependent (72% vs. 76%) and required less treatment with a second-line agent (47% vs. 58%) in the study sample. Over half (56%) of the cohort received treatment with one or more second-line agents. The mean number of second-line agents used for each patient was 1.9 (SD, 1.2). The most used second-line therapy was rituximab, followed by etrombopag and splenectomy. These also generated the highest rates of complete response (60.3%, 72.1%, and 71.8% respectively). The most unfavorable side effect profiles were seen in long-term corticosteroids and splenectomy.

Conclusion

A wide range of "second-line" agents were used across centers with variable response rates and side effect profiles. Findings suggest greater effectiveness of rituximab and TPO-A, supporting their use earlier in the treatment course of patients with ITP across Australia.

An Analysis of the Serum Metabolomic Profile for the Radiomitigative Effect of the Thrombopoietin Receptor Agonist Romiplostim in Lethally Whole-Body-Irradiated Mice

The thrombopoietin receptor agonist romiplostim (RP) was recently approved by the US Food and Drug Administration for improving survival in patients acutely exposed to myelosuppressive doses of radiation. Our previous studies with mice have shown that RP administration after lethal irradiation not only completely rescues irradiated mice but also shows mitigative effects on their hematopoiesis and multiple organ injury, including that of the lung, bone marrow, small intestine, and liver. However, the mechanism by which RP functions as a radiomitigator remains unclear. In the present study, we applied a metabolomics approach, which has the ability to reflect the status of an organism directly and accurately, helping to elucidate the biology of treatment responses. Our results showed that the disruption of several metabolites and pathways in response to total body irradiation was partially corrected by RP administration. Notably, RP-corrected metabolites and pathways have been reported to be indicators of DNA damage and lung, bone marrow, small intestine, and liver injury. Taken together, the present findings suggested that the radiomitigative effect of RP is partially involved in the recovery of organ injury, and the identified metabolites may be a useful biomarker of the survival likelihood following radiation exposure.

Eltrombopag and its beneficial role in management of ulcerative Colitis associated with ITP as an upfront therapy case report

Eltrombopag can be used safely as upfront medication in the management of ulcerative colitis as well as ITP, and it showed a beneficial effect in both disorders.

Eltrombopag Effectiveness and Tolerability in Chronic Immune Thrombocytopenia: A Meta-Analysis

Eltrombopag is an orally administered, non-peptide, thrombopoietin receptor agonist which initiates thrombopoietin signaling and stimulates the production of normally functioning platelet. We aimed to do a systematic review and meta-analysis of currently available published data to verify whether eltrombopag treatment in patients with chronic immune-mediated thrombocytopenia can prolong survival. We searched for published, randomized, controlled trials in PubMed, Cochrane and Scopus databases using the following search strategy ("Eltrombopag" OR "Benzoates" OR "Hydrazines") AND ("Idiopathic Thrombocytopenic Purpura" OR "immune thrombocytopenia" OR "Idiopathic Thrombocytopenic Purpuras" OR "Immune Thrombocytopenia" OR "Autoimmune Thrombocytopenia" OR "Werlhof"). The pooled relative risk (RR) showed that eltrombopag group has significantly higher overall platelet response than placebo group (MD = 3.42, 95% CI [2.51, 4.65], P > .0001); pooled results were homogenous (P = .27, I2 = 22%). The pooled relative risk showed that eltrombopag group has lower incidence of any bleeding than placebo group (MD = 0.65, 95% CI [0.48, 0.87], P = .003); pooled results were heterogenous (P = .001, I2 = 75%) and the detected heterogeneity was best resolved after excluding Bussel et al (P = .10). Homogeneous results were still favored eltrombopag group (MD = 0.75, 95% CI [0.60, 0.93], P = .008).

Steroid-Refractory Chronic Idiopathic Thrombocytopenic Purpura Responding to Combination Therapy With Eltrombopag and Rituximab

Idiopathic thrombocytopenic purpura (ITP) is a disease in which the immune system attacks platelets and decreases their number, which increases the patient's risk of bleeding. ITP is diagnosed by exclusion and usually manifests as acute disease. It is self-limiting in pediatric patients, while it tends to be a chronic disease in adults. Treatment of ITP focuses on maintaining a sufficient platelet count to decrease the risk of bleeding rather than normalize the platelet count. Most patients respond to first-line treatments, such as steroids and intravenous immunoglobulin (IVIG). However, some cases can become steroid-dependent or unresponsive to first-line therapy, in which case, second-line therapy is required to control symptoms or the platelet count. Second-line therapy includes either rituximab or a thrombopoietin receptor agonist (eltrombopag, romiplostim). In a few cases, when second-line therapy alone is insufficient to control the disease, a combination of therapies is required to control the symptoms and platelet count. Here, we present a case of a 41-year-old man with refractory ITP who did not respond to first-line treatment with either steroids or IVIG or a combination of the two, and also did not respond to eltrombopag alone and required a combination of eltrombopag and rituximab to control his disease.

A Multi-Center Study on the Efficacy of Eltrombopag in Management of Refractory Chronic Immune Thrombocytopenia: A Real-Life Experience

Objective

The aim of the present study was to evaluate the efficacy and safety of eltrombopag, an oral thrombopoietin receptor agonist, in patients with chronic immune thrombocytopenia (ITP).

Materials and Methods

A total of 285 chronic ITP patients (187 women, 65.6%; 98 men, 34.4%) followed in 55 centers were enrolled in this retrospective cohort. Response to treatment was assessed according to platelet count (/mm³) and defined as complete (platelet count of >100,000/mm³), partial (30,000-100,000/mm³ or doubling of platelet count after treatment), or unresponsive (<30,000/mm³). Clinical findings, descriptive features, response to treatment, and side effects were recorded. Correlations between descriptive, clinical, and hematological parameters were analyzed.

Results

The median age at diagnosis was 43.9±20.6 (range: 3-95) years and the duration of follow-up was 18.0±6.4 (range: 6-28.2) months. Overall response rate was 86.7% (n=247). Complete and partial responses were observed in 182 (63.8%) and 65 (22.8%) patients, respectively. Thirty-eight patients (13.4%) did not respond to eltrombopag treatment. For patients above 60 years old (n=68), overall response rate was 89.7% (n=61), and for those above 80 years old (n=12), overall response rate was 83% (n=10). Considering thrombocyte count before treatment, eltrombopag significantly increased platelet count at the 1^st, 2^nd, 3^rd, 4^th, and 8^th weeks of treatment. As the time required for partial or complete response increased, response to treatment was significantly reduced. The time to reach the maximum platelet levels after treatment was quite variable (1-202 weeks). Notably, the higher the maximum platelet count after eltrombopag treatment, the more likely that side effects would occur. The most common side effects were headache (21.6%), weakness (13.7%), hepatotoxicity (11.8%), and thrombosis (5.9%).

Conclusion

Results of the current study imply that eltrombopag is an effective therapeutic option even in elderly patients with chronic ITP. However, patients must be closely monitored for response and side effects during treatment. Since both response and side effects may be variable throughout the follow-up period, patients should be evaluated dynamically, especially in terms of thrombotic risk factors.

Efficacy and tolerability of old and new drugs used in the treatment of immune thrombocytopenia: Results from a long-term observation in clinical practice

Background

Many patients with immune thrombocytopenia (ITP) may require special attention and long-term treatment. Little is known on the efficacy and tolerability of the drugs used in practice.

Material and methods

We retrospectively reviewed the results of therapy of 400 patients with chronic ITP. All Patients were treated at our institution between 1996–2016 under consideration of guidelines, general recommendations, and individual aspects, including gender, age, weight, comorbidity, patient’s medical history and bleeding risk.

Results

Treatment was not required in 25% of patients (n = 100) during observation. In treated patients (n = 300), the rate of patients that responded and tolerated treatment with prednisolone was 59% (52/88), with azathioprine 32% (29/90), with eltrombopag 49% (31/63), with romiplostim 59% 27/45, with IVIG (intravenous immunoglobulines) 75% (94/126), with anti-D 37% (19/52) and with dexamethasone 60% (25/42) patients. Eighteen treated patients (6%) entered sustained remission after treatment with various drugs. Twenty-six patients underwent splenectomy (Splx) resulting in sustained remission in 15 cases (60%). Only two patients remained refractory to Splx and to all used drugs.

Discussion

None of the currently available drugs used in the treatment of ITP are invariably safe and effective. Responses, the duration of response, intolerability, and the course of disease are unpredictable. Although the treatment of ITP has considerably improved in the recent years, the currently available drugs may rarely cure affected patients. The need for safe and effective therapy in ITP is evident. Optimal treatment decisions for each patient remains a challenge in many cases.

Cytokine changes in response to TPO receptor agonist treatment in primary immune thrombocytopenia

Thrombopoietin receptor agonists (TPO-RAs) have been clinically used in primary immune thrombocytopenia (ITP) with favorable outcomes, while their effect on cytokine regulation in ITP remains unknown. In the present study, plasma and mRNA expression levels of interleukin (IL)-2, interferon gamma (IFN-γ), IL-4, IL-17A, and transforming growth factor-β1 (TGF-β1) were determined by ELISA and real-time quantitative PCR in 26 corticosteroid-resistant/relapsed ITP patients receiving eltrombopag or rhTPO therapy and 15 healthy controls (HCs). Results showed that plasma and mRNA levels of IL-2, IFN-γ, IL-4, and IL-17A in ITP patients did not change significantly after TPO-RA treatment, whereas TGF-β1 levels increased remarkably. The pre- and post-treatment plasma and mRNA levels of IFN-γ and IL-2 were significantly higher, while the pre- and post-treatment IL-4 levels as well as the pre-treatment TGF-β1 levels were remarkably lower in ITP patients compared with HCs. There was no significant difference in TGF-β1 levels between TPO-RA-treated ITP patients and HCs. No statistical difference was found in plasma levels of IL-17A between ITP patients before or after treatment and HCs. However, the pre- and post-treatment mRNA expression of IL-17A and retinoic orphan receptor (ROR) γt in ITP patients were higher than that in HCs. Overall, these findings indicated that TPO-RA treatment could promote the secretion of TGF-β1, while it could not correct the Th1 and Th17 polarization in ITP patients. This study might improve our understanding of the mechanism of action of TPO-RAs and provide important information for optimizing therapeutic strategies for ITP.

Thrombopoietin receptor agonists shift the balance of Fcγ receptors toward inhibitory receptor IIb on monocytes in ITP

Elevated expression of the activating Fcγ receptor (FcγR) I and FcγRIIa together with decreased expression of the inhibitory FcγRIIb are involved in the pathogenesis of primary immune thrombocytopenia (ITP). Thrombopoietin receptor agonists (TPO-RAs) have been used clinically for the management of ITP; however, little is known about the effect of TPO-RAs on FcγR modulation in ITP. In this prospective study, we measured the alteration in monocyte FcγR expression from 21 corticosteroid-resistant/relapsed patients with chronic ITP receiving eltrombopag therapy. Results showed that the mRNA and protein levels of FcγRIIb were significantly elevated after 6-week eltrombopag treatment. Concurrently, FcγRI and IIa levels decreased remarkably, whereas FcγRIII expression did not change. In vitro phagocytosis assays indicated that a shift in the balance of FcγR toward inhibitory FcγRIIb on monocytes was accompanied with a considerable decrease in monocyte/macrophage phagocytic capacity. The response to eltrombopag therapy in patients with ITP was associated with FcγR phenotype and functional changes of monocytes/macrophages. Moreover, the plasma transforming growth factor-β1 (TGF-β1) concentrations increased significantly in eltrombopag responders. Modulation of monocyte FcγR balance by TPO-RAs was also found in a murine model of ITP established by transferring splenocytes from immunized CD61 knockout mice into CD61(+) severe combined immunodeficient mice. Romiplostim administration in ITP mice significantly upregulated inhibitory FcγRII expression and downregulated activating FcγRI expression. These findings showed that recovery of platelet counts after TPO-RA treatment in ITP is associated with the restoration of FcγR balance toward the inhibitory FcγRIIb on monocytes, and suggested that thrombopoietic agents have a profound effect on immune modulation in ITP. This study is registered at ClinicalTrials.gov as #NCT01864512.

Expression of IL4 (VNTR intron 3) and IL10 (-627) genes polymorphisms in childhood immune thrombocytopenic purpura

OBJECTIVE

Immune thrombocytopenic purpura (ITP) is an acquired autoimmune disorder caused by the production of antiplatelet antibodies. These autoantibodies opsonize platelets for splenic clearance, resulting in low levels of circulating platelets. Interleukin 4 (IL4) and interleukin 10 (IL10) are important immunoregulatory cytokines mainly produced by macrophages, monocytes, T cells, B cells, and mast cells. Our study was aimed at detecting the frequency of IL4 (VNTR intron 3) and IL 10 (-627) gene polymorphisms in Egyptian ITP children as genetic markers for ITP risk and clarifying their possible role in the pathogenesis of ITP as well as their correlation with the clinical presentation and laboratory data.

METHODS

IL4 (VNTR intron 3) and IL10 (-627) gene polymorphisms were studied in 70 ITP patients and 50 age- and sex-matched healthy controls using polymerase chain reaction-restriction fragment length polymorphism assay (PCR-RFLP).

RESULTS

IL4 RP2 and IL10 A alleles were detected more frequently among ITP patients compared to controls. A statistically significant difference was observed in IL10 and IL4 gene polymorphism distribution between acute and chronic ITP patients, with higher A allele and RP2 allele among chronic ITP patients versus acute ITP patients. Combined polymorphisms of IL4 and IL10 genes were associated with greater risk of ITP.

CONCLUSION

IL4 and IL10 gene polymorphisms may contribute to susceptibility for ITP in children.

Perioperative care of a patient with refractory idiopathic thrombocytopenic purpura undergoing total knee arthroplasty

Idiopathic thrombocytopenic purpura (ITP) is an autoimmune disorder leading to low platelet count and an increased risk of bleeding. Major joint replacement surgery in a patient with ITP can be associated with severe postoperative bleeding. We present our experience of perioperative management in a patient with severe refractory chronic idiopathic thrombocytopenic purpura who successfully underwent a cemented total knee replacement.

Use of the novel thrombopoietin receptor-agonist romiplostim, in combination with steroids and immunoglobulins for the increase of platelets prior to splenectomy, in refractory immune thrombocytopenia: a case report

This case report describes a patient with relapsed primary immune thrombocytopenic purpura (ITP), in which splenectomy was not possible due to the persistence of a low platelet count despite treatment with corticosteroids, intravenous immunoglobulins (IVIG) and platelet transfusion treatment. As an attempt to increase platelet count prior to performing splenectomy, the thrombopoietin receptor agonist, romiplostim, was administered in combination with steroids and IVIG. A single administration of romiplostim was found to be markedly effective, allowing a rapid and notable platelet increase, required for a well tolerated splenectomy. This case confirms the potent activity of romiplostim in ITP, and indicates that patients with recurrent primary ITP who are unresponsive to conventional immunosuppressive therapy may benefit from the addition of a short course of romiplostim.

Romiplostim: a review of its use in immune thrombocytopenia

Romiplostim (Nplate®) is an Fc-peptide fusion protein (peptibody) that acts as a thrombopoietin receptor agonist; it has no amino acid sequence homology with endogenous thrombopoietin. This article reviews the clinical efficacy and tolerability of subcutaneous romiplostim in adults with immune thrombocytopenia (ITP), as well as summarizing its pharmacological properties. The efficacy of 12 or 24 weeks' therapy with subcutaneous romiplostim was compared with that of placebo in patients with ITP in three randomized, double-blind, multicentre, phase III trials. In the two 24-week trials, the durable platelet response rate (primary endpoint) was significantly higher with romiplostim than with placebo in both splenectomized and nonsplenectomized patients. In addition, the majority of romiplostim recipients were able to discontinue or reduce their concurrent ITP therapy, and romiplostim improved health-related quality of life (HR-QOL). In the 12-week trial in splenectomized or nonsplenectomized Japanese patients with ITP, the median number of weeks with a platelet response (primary endpoint) was significantly higher with romiplostim than with placebo. Two extension studies (with median durations of romiplostim treatment of 78 and 100 weeks) demonstrated that long-term therapy with romiplostim maintained platelet counts in the target range in patients with ITP. In a randomized, open-label, multicentre, 52-week, phase IIIb trial, romiplostim was more effective than the medical standard of care in nonsplenectomized patients with ITP who had received at least one prior ITP treatment. Significantly fewer patients receiving romiplostim versus the medical standard of care experienced treatment failure or required splenectomy (co-primary endpoints), and clinically meaningful improvements from baseline in HR-QOL scores were seen with romiplostim. Subcutaneous romiplostim was generally well tolerated in patients with ITP; in short-term trials, the majority of adverse events were of mild to moderate severity and appeared to be related to the underlying thrombocytopenia. The incidence of bleeding events of at least grade 3 severity did not significantly differ between romiplostim and placebo recipients, and was significantly lower with romiplostim than with the medical standard of care. Romiplostim did not appear to be associated with an increased risk of haematological malignancies or an increased risk of thrombotic events. Although binding antibodies against romiplostim or thrombopoietin developed in some romiplostim recipients, with neutralizing antibodies to romiplostim detected in two romiplostim recipients, antibodies cross reacting to thrombopoietin have not been detected. Romiplostim was associated with modest increases in bone marrow reticulin in some patients with ITP; reductions in reticulin were usually seen when romiplostim was discontinued. In conclusion, subcutaneous romiplostim is a valuable agent for use in patients with refractory chronic ITP.

Eltrombopag: an oral thrombopoietin receptor agonist for the treatment of idiopathic thrombocytopenic purpura

BACKGROUND

Idiopathic thrombocytopenic purpura (ITP) is a relatively rare acquired autoimmune disease characterized by either decreased platelet production or increased platelet destruction leading to reduced platelet counts and increased risk of bleeding. Immune modulators have been used in treatment; however, a novel class of thrombopoietin mimetics has recently been developed. Eltrombopag is approved for patients with chronic ITP who have failed initial treatments with traditional immune modulators or splenectomy.

OBJECTIVES

The goals of this review were to summarize the pharmacology, pharmacokinetic properties, efficacy, and tolerability of eltrombopag and review the approved and investigational uses of this drug.

METHODS

A search of Cochrane Central Register of Clinical Trials and clinicaltrials.gov was conducted using the terms eltrombopag or SB-497115-GR. In addition, all reviews and preclinical and clinical studies published in English between January 1980 and January 2011 were identified in PubMed and Cochrane Database of Systemic Reviews using the same terms.

RESULTS

A total of 153 publications and 13 clinical trials were identified; 14 publications were excluded because they were not published in English. A Phase III trial randomized 114 patients with ITP 2:1 to eltrombopag 50 mg or placebo and demonstrated by day 43 a significantly greater proportion of patients responding in the eltrombopag group than in the placebo group (59% vs 16%, odds ratio [OR] = 9.61; 95% CI, 3.31-27.86; P < 0.0001). The mean percentage change of platelets from baseline in the eltrombopag group was double that of the placebo group at day 8 and was sustained several-fold higher throughout the remainder of the treatment period. Another Phase III trial evaluated the efficacy and safety of eltrombopag compared with placebo over 6 months. The odds of responding (defined as a platelet count of 50-400 × 10(9)/L) were 8 times higher in patients receiving eltrombopag than in those in the placebo group (95% CI, 3.59-18.73; P < 0.0001). Bone marrow fibrosis and hepatotoxicity are the most serious adverse effects, and nausea and vomiting are the most common. Eltrombopag is also being evaluated in the treatment of thrombocytopenia secondary to hepatitis C infection, chemotherapy, acute leukemia, and myelodysplasias.

CONCLUSION

Eltrombopag is well tolerated and effective in raising platelet counts in patients with chronic ITP.

The scintigraphic index spleen/liver at 30 minutes predicts the success of splenectomy in persistent and chronic primary immune thrombocytopenia

Splenectomy is considered the second-line of treatment in patients with chronic primary immune thrombocytopenia (ITP) in whom glucocorticoids have failed. Some patients do not respond to splenectomy or they have postoperative complications. Based on our previous experience using kinetic and scintigraphic parameters, we did a retrospective study with the aim of comparing all these parameters as a means of predicting the success of splenectomy in persistent and chronic primary ITP. Forty-one consecutive patients with chronic primary ITP refractory to prednisone, who had been splenectomized, were included in the study. The response to splenectomy was assessed by evaluating bleeding and platelet counts before and at different times after surgery. A complete platelet kinetic study was performed before the splenectomy using autologous (111) In-labeled platelets. The scintigraphic parameters measured included different indices between spleen/heart, liver/hearth, and spleen/liver. Thirty-six patients gave a complete response after splenectomy and five patients did not respond. A statistically significant difference between both groups was found with initial platelet recovery and with some scintigraphic indices which also showed a variable prediction value for the success of splenectomy. Among these indices, the spleen/liver at 30 minutes demonstrated a predictive value with a 100% of sensitivity and a 100% of specificity.

CONCLUSION

some platelet kinetic parameters and scintigraphic indices, in particular the spleen/liver at 30 minutes, were useful to predict the outcome of splenectomy in persistent and chronic primary ITP and, therefore, they should be taken into account when deciding whether or not to perform a splenectomy.