Efficacy and safety of thrombopoietin receptor agonists in children with chronic immune thrombocytopenic purpura: meta-analysis

Immune thrombocytopenic purpura (ITP) is an autoimmune disorder presenting with low platelet count <100 × 10⁹/L. The condition affects both adults and children. Thrombopoietin receptor agonists (TPO-RAs) are second-line of therapy that includes Romiplostim and Eltrombopag, which stimulate the production of normally functioning platelets. Although the biological effect of these drugs is well established, there has not been a meta-analysis in children. To estimate the efficacy and safety of Romiplostim and Eltrombopag, we performed a systematic review and meta-analysis in children with chronic ITP. Systematic literature search was conducted in the following database: PubMed, EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL). Review Manager 5.3 for Windows was used to analyze the data. Five randomized controlled trials with total of 261 pediatric patients from 1–17 years of age were included. The efficacy and safety analysis showed TPO-RA groups were superior over placebo, and there was no difference in adverse event occurrence between TPO-RA (Romiplostim and Eltrombopag) and placebo groups. The efficacy and safety of Eltrombopag did not differ significantly from those of Romiplostim. Both drugs were effective in treatment of children with chronic ITP. Our findings extend the currently available data on ITP treatment and is helpful for pediatric health providers and for the design of future clinical trials.     

Serum thrombopoietin levels in patients with aplastic anaemia

Endogenous serum thrombopoietin (TPO) levels were measured in 31 patients with aplastic anaemia (AA) using an enzyme immunoassay with a sensitivity of 20 pg/ml. The median platelet count for all AA patients was 30 ± 29 × 10⁹/l (range 5–102) compared with a median of 284 ± 59 × 10⁹/l (range 148–538) for normal controls. Serum TPO levels were significantly elevated in all patients compared with normals (1706 ± 1114.2, range 375–5000 v 78 ± 54, range 16.5–312.9, P  < 0.0001). There was no correlation between serum TPO levels and the degree of thrombocytopenia in AA patients, but TPO levels were significantly higher in patients who were platelet transfusion dependent than in patients who were transfusion independent ( P  < 0.01). There was a trend for higher TPO levels in patients with severe AA compared with non-severe AA patients. Clinical trials of TPO and a related truncated, pegylated molecule, megakaryocyte growth and development factor (PEG-rHuMGDF), are awaited to determine whether treatment with these drugs will result in increased platelet counts in patients with AA.     

Serum thrombopoietin levels in relation to disease status in patients with immune thrombocytopenic purpura

Pre- and post-treatment serum thrombopoietin (TPO) concentration was measured in 35 patients with immune thrombocytopenic purpura (ITP). Mean post-treatment levels were significantly lower (P = 0.02) than pretreatment and not different for treatment modality. No significant correlation between pre- or post-treatment TPO and platelet counts was demonstrable (R = -0.325, P = 0.056 and R = -0.227, P = 0.190 respectively). In patients with very low platelet counts (< or =20 x 10(9)/l), pretreatment serum TPO was significantly higher than in patients with higher counts (P = 0.033). The logarithm of the platelet turnover rate, measured in 15 patients, correlated with pretreatment TPO levels (R = 0.64). These findings suggest a contributory role for TPO in the mechanism of ITP.     

Oral cyclic megadose methylprednisolone therapy for chronic immune thrombocytopenic purpura in childhood

The objectives of this study were to investigate the effectiveness of oral megadose methylprednisolone (OMMP) therapy in children with chronic immune thrombocytopenic purpura (ITP). Twenty-two patients were given oral methylprednisolone daily for 7 d (30 mg/kg for 3 d and then 20 mg/kg for 4 d). OMMP therapy was repeated once per month if the platelet count was less than 20,000/mm3 at the 30th day of therapy, for up to six courses. The number of platelets of all patients increased gradually during the OMMP therapy, with a peak number at the 7th day, then decreased until the 14th day, and remained relatively stable until 12 months. During the study no patient had a platelet count less than 20,000/mm3 at the 3rd day and 50,000/mm3 at the 7th day. Although the number of platelets was gradually decreased between the 7th and 14th days, it remained above 100,000/mm3 for at least 12 months in the nine patients, and above 20,000/mm3 in the four patients. None of these 13 patients required hospitalization or therapy during the follow-up period. All of the patients tolerated the medication well. None of them reported side-effects that were severe enough to discontinue therapy. We conclude that OMMP therapy is a safe, easy and effective therapy in children with refractory chronic ITP, and it may provide long-term remission in about two thirds of the patients.     

Therapeutic implications of T-cell clonopathy of unknown significance in chronic immune thrombocytopenic purpura

Immune thrombocytopenic purpura (ITP) is typically considered an autoimmune disorder related to the production of autoantibodies; however, recent evidence indicates that cell-mediated cytotoxicity may be important pathogenetically in some cases. We describe seven patients with chronic ITP and concurrent T-cell clonopathy of unknown significance (TCUS), who failed various treatment regimens for ITP, including steroids, gamma globulins, splenectomy and rituximab, but had anecdotal success with azathioprine. These observations support the notion that ITP has heterogeneous biologic mechanisms, and that patients with persistent chronic ITP should be evaluated for T-cell clonality and considered for treatment options that are directed against cytotoxic T-cells.     

Thrombopoietin serum levels in patients with aplastic anaemia: correlation with platelet count and persistent elevation in remission

In an attempt to evaluate the role of thrombopoietin (TPO) in the pathobiology of aplastic anaemia (AA), we have examined TPO levels in sera from 54 AA patients and 119 healthy controls. A total of 92 samples were collected from AA patients: 43 samples were harvested at diagnosis, 23 samples in the cytopenic period after treatment, and 26 samples when patients were in partial (n = 10) or complete remission (n = 16) following immunosuppressive treatment. TPO serum levels were assessed by a sandwich-antibody ELISA that utilized a polyclonal rabbit antiserum for both capture and signal. Serum samples from normal donors revealed a mean TPO level of 95.3 ± 54.0 pg/ml (standard deviation). Mean TPO levels in AA sera collected at diagnosis and before onset of treatment were 2728 ± 1074 pg/ml (P < 0.001 compared to normal controls; mean platelet count at that time: 27 × 10⁹/l). TPO serum levels of AA patients in partial or complete remission after immunosuppressive treatment were significantly lower than TPO levels at diagnosis (P < 0.001). However, despite normal platelet counts (mean 167 × 10⁹/l), TPO levels remained significantly elevated in complete remission (mean TPO 1009 ± 590 pg/ml, P < 0.001 compared to normal controls). There was a significant inverse correlation between serum TPO levels and platelet counts in AA patients who were not transfused for at least 2 weeks prior to sample collection (coefficient of correlation (r) = ?0.70, P < 0.0001). In summary, TPO levels were highly elevated in sera of patients with AA. Thus there is no evidence to suggest an impaired TPO response contributing to thrombocytopenia in AA. Thrombopoietin did not return to normal levels in remission, indicating a persisting haemopoietic defect in remission of AA. We hypothesize that elevated levels of TPO may be required to maintain normal or near normal platelet counts in remission of AA.     

Detection of platelet-associated IgG in chronic immune thrombocytopenic purpura using antibody-coated polyacrylamide beads

Summary Platelet-associated IgG (PAIgG) was detected by means of anti-human IgG coated polyacrylamide beads (Immunobeads) technique in 32 patients with chronic ITP. Both a direct test (with in vivo sensitized platelets) and an indirect test (with in vitro loaded platelets) were carried out. The percent of rosette forming beads was both in the direct test (41.2%) and in the indirect test (32.6%) significantly higher in the cases of chronic ITP patients than in the controls (2.5% and 3.2%, respectively). These results confirm the diagnostic value of this new, relatively simple and rapid method in routine clinical practice.     

Concurrent thrombotic thrombocytopenic purpura and immune thrombocytopenic purpura in an HIV-positive patient: Case report and review of the literature

Immune thrombocytopenic purpura (ITP) and thrombotic thrombocytopenic purpura (TTP) have each been associated with HIV infection. Sequential occurrence of these two diseases with a disease-free interval has been occasionally reported in the literature, whereas simultaneous manifestations of these two diseases have not been described. Here, we report an AIDS patient who was initially diagnosed as having TTP and showed an apparent partial response to plasmapheresis but was found to have a clinical course similar to ITP. Although precise mechanisms for the development of TTP and ITP in these patients are unclear, we offer several hypotheses. It is important to recognize that these two processes may be seen concurrently. © 1996 Wiley-Liss, Inc.     

Clinical characteristics and treatment outcomes in patients with Helicobacter pylori-positive chronic immune thrombocytopenic purpura

Abstract

Immune thrombocytopenic purpura (ITP) is the condition caused by increased platelet destruction and or decreased platelet production. Previous studies have demonstrated the association and efficacy of Helicobacter pylori (H. pylori) eradication therapy in patients with chronic ITP. Data in Thai patients, however, are limited. A prospective cross-sectional analytic study was conducted in adult patients with chronic ITP to determine the prevalence and clinical predictive factors of H. pylori infection and evaluate the efficacy of H. pylori eradication therapy. H. pylori-infected patients received eradication therapy (omeprazole 40?mg/day, clarithromycin 1000?mg/day, amoxicillin 2000?mg/day) for 2 weeks. The platelet counts at baseline and monthly for 6 months after the end of treatment were evaluated. Of the 25 patients, 9 patients (36%) had H.pylori infection. H. pylori infection is higher among women than men. There were two clinical factors included 1) relapsed ITP 2) response after the first-line treatment statistically proven to be associated with H. pylori infection with an odds ratio and p value of 7.7, p?=?0.035 and ND (not determined due to small sample size), p?<?0.001. Nearly 80% of infected patients had the platelet count response after eradication therapy with the median time to response of 4 months. The prevalence of H. pylori infection is modest in Thai adult patients with chronic ITP. A history of relapsed ITP and high quality of response after first-line treatment indicated H. pylori infection. Therefore, the urea breath test should be recommended in patients who have a relapsed ITP condition with a history of good response after first-line therapy.     

Antiplatelet antibodies in childhood idiopathic thrombocytopenic purpura

Antiplatelet antibodies were shown by the Handin and Stossel method in the sera of all 103 patients with acute idiopathic thrombocytopenic purpura (ITP) and in 100 cases following recovery from it. These antibodies were also shown in the sera of all 46 patients with chronic ITP and 32 cases after recovery. The decrease in level of antiplatelet antibodies was significant in all these children following recovery (P less than 0.001 for acute ITP, P less than 0.05 for chronic ITP). Antiplatelet antibodies could be determined in 67 acute and 21 chronic ITP cases in thrombocytopenic phase and following recovery, which showed very significant decreases in levels in each case in a later period. Antiplatelet antibody levels corresponding to the thrombocytopenic phase and recovery in acute and chronic ITP were significantly higher than normal and thrombocytopenic control values (P less than 0.001 for each).     

Measurement of endogenous plasma thrombopoietin in patients with acquired aplastic anaemia by a sensitive enzyme-linked immunosorbent assay

We measured the endogenous plasma concentration of thrombopoietin (TPO) in 76 patients with acquired aplastic anaemia (AA) by a sensitive sandwich enzyme-linked immunosorbent assay (ELISA). The plasma TPO concentrations were significantly higher in AA patients when compared to healthy control subjects ( P  < 0.0001) and there was a significant negative correlation between plasma TPO concentrations and platelet counts in 54 AA patients who had not received any platelet transfusions prior to sampling. On the other hand, there was no statistically significant correlation between the TPO concentrations and platelet counts in 22 AA patients who had previously received platelet transfusions.
We studied serial changes of plasma TPO concentration in 24 patients who showed an increase in their platelet counts following bone marrow transplantation or immunosuppressive (IS) therapy. Although a decrease in plasma TPO concentration was observed, levels remained above the range of normal healthy controls even in the patients who attained normal platelet counts following therapy. A decrease in TPO concentrations was observed in only half of the responders to IS therapy. Whether exogenous TPO will result in increased platelet counts in AA patients with high TPO levels remains to be determined.     

Treatment of refractory chronic idiopathic thrombocytopenic purpura with high dose intravenous immunoglobulin

Summary Three patients with a history of chronic idiopathic thrombocytopenic purpura stretching back over 20 years are reported. Despite splenectomy and immunosuppressive therapy satisfactory control of their disease has not been achieved. They had remained refractory to all therapeutic manoeuvres with corticosteroids and immunosuppressives for years with thrombocyte counts between 5,000 and 25,000/l and the concommitant risk of bleeding.This report describes the treatment of bleeding complications in these patients with high dose intravenous immunoglobulin; the peripheral blood thrombocyte count increased in all three patients from subnormal towards normal, but 2 to 4 weeks later returned to its initial low value.During the therapeutically induced raised thrombocyte count a normal bleeding time and only a moderate inhibition of thrombocyte adhesion and aggregation was observed resulting in reasonable haemostasis. High dose intravenous immunoglobulin is therefore a practical method for the control of bleeding complications in patients with refractory chronic idiopathic thrombocytopenic purpura. A clear explanation for its mode of action has not been found — the lymphocyte subpopulations remained unchanged and immunoglobulin production in vitro during the course of treatment was only minimally decreased.     

New therapeutic options for adult chronic immune thrombocytopenic purpura: a brief review

BACKGROUND: Patients with chronic immune thrombocytopenic purpura (ITP) only require treatment if they are bleeding, or prior to scheduled operations. Patients are also treated if platelet counts are very low. Some patients become refractory, relapse or do not respond to treatment with steroids. Splenectomy is effective in raising the platelet count in most patients, but as spontaneous remission may occur even after 1 year or more, it is justified to defer splenectomy. Furthermore, splenectomy and/or first-line treatment modalities may not suit all patients. Therefore, alternatives are desirable. MATERIALS: This review will focus on anti-B cell therapy with rituximab, and two thrombopoietin mimetic agents that have entered clinical trials, AMG 531 and eltrombopag. These therapeutics have been studied in patients who were refractory to first-line treatment and/or splenectomy, and to defer splenectomy. RESULTS: There are no controlled trials with rituximab, but clinical experience has shown a success rate of 40% to 60%. Encouraging phase 1 and 2 data have been published for both thrombopoietin mimetics; preliminary data from an open-label extension trial with AMG 531 and from phase 3 studies with eltrombopag further confirm their efficacy. CONCLUSION: Clinical experience will ultimately determine the appropriate indications of these new treatments for ITP.     

重组人血小板生成素治疗特发性血小板减少性紫癜的临床对照试验

目的:评价重组人血小板生成素(rhTPO)对特发性血小板减少性紫癜(ITP)的疗效和安全性。方法:21例ITP患者采用随机区组,分成试验组和对照组2组。试验组皮下注射rhTPO 1.0μg/kg,1次/d,疗程14 d。对照组在服用达那唑14 d后如血小板仍≤20×109/L,加用rhTPO皮下注射,1.0μg/kg,疗程14 d。2组在整个试验阶段均服用达那唑,0.2 g,每日3次。结果:试验组用药前血小板计数的中位数为8.0(4.0～15.0)×109/L,用rhTPO后血小板最高值为100.0(49.0～118.5)×109/L,与用药前相比P<0.01。停药后血小板计数逐渐回落,至开始治疗后28 d,血小板计数降至39.0(22.0～68.5)×109/L。对照组用药前血小板计数的中位数为6.0(4.0～10.0)×109/L,第1阶段(1～14 d)仅用达那唑治疗血小板最高值为33.0(23.0～72.0)×109/L。第2阶段(14～28 d)加用rhTPO,血小板计数最高值为111.5(60.0～152.0)×109/L,与用药前及第1阶段最高值相比均P<0.01。停药后血小板计数逐渐下降,至4...     

Serum sickness with an elevated level of human anti-chimeric antibody following treatment with rituximab in a child with chronic immune thrombocytopenic purpura

Rituximab, a chimeric murine/human monoclonal anti-CD20 antibody, was licensed for the treatment of B-cell lymphoma and has also shown efficacy against autoimmune diseases such as immune thrombocytopenic purpura (ITP). It is relatively safe; however, about 1–20% of patients were reported to have developed rituximab-induced serum sickness, which is more common among patients with autoimmune conditions than among those with hematologic malignancies. Here we describe a pediatric patient with steroid-dependent chronic ITP who presented with arthralgia and fever ten days after the second infusion of rituximab (on day 10), and presented with malaise and maculopapular rash on day 21. Oral prednisolone was started and his symptoms resolved. He had an elevated level of human anti-chimeric antibody (HACA) on day 27; thereafter, the HACA level slowly decreased. To our knowledge, among pediatric patients who received rituximab for chronic ITP, this is the sixth documented case of serum sickness and the only one who manifested an elevated level of HACA. Rituximab is a beneficial treatment option against chronic ITP; however, the risk of serum sickness should be considered. Steroid, usually used for the treatment of serum sickness, may prevent the development of severe serum sickness when administered during and after rituximab treatment.     

Rituximab therapy for chonic and refractory immune thrombocytopenic purpura: a long-term follow-up analysis

The aim of this study was to evaluate the long-term response to rituximab in patients with chronic and refractory immune thrombocytopenic purpura (ITP). Adults with ITP fail to respond to conventional therapies in almost 30% of cases, developing a refractory disease. Rituximab has been successfully used in these patients. We used rituximab at 375 mg/m2, IV, weekly for a total of four doses in 18 adult patients. Complete remission (CR) was considered if the platelet count was >100 x 10(9)/l, partial remission (PR) if platelets were >50 x 10(9)/l, minimal response (MR) if the platelet count was >30 x 10(9)/l and <50 x 10(9)/l, and no response if platelet count remained unchanged. Response was classified as sustained (SR) when it was stable for a minimum of 6 months. Median age was 43.5 years (range, 17 to 70). Median platelet count at baseline was 12.5 x 10(9)/l (range, 3.0 to 26.3). CR was achieved in five patients (28%), PR in five (28%), MR in four (22%), and two patients were classified as therapeutic failures (11%). Two additional patients were lost to follow-up. The median time between rituximab therapy and response was 14 weeks (range, 4 to 32). SR was achieved in 12 patients (67%). There were no severe adverse events during rituximab therapy. During follow-up (median, 26 months; range, 12 to 59), no other immunosuppressive drugs were used. In conclusion, rituximab therapy is effective and safe in adult patients with chronic and refractory ITP. Overall response rate achieved is high, long term, and with no risk of adverse events.     

Rotational thromboelastometry parameters as predicting factors for bleeding in immune thrombocytopenic purpura

Objective/BackgroundPatients with immune thrombocytopenic purpura (ITP) often present with a severe reduction in platelet counts and suffer from an increased risk of bleeding. However, platelet counts do not accurately predict bleeding risk in these patients.MethodsWe thereby conducted a case series prospective study to compare the ability to predict hemorrhage in ITP patients between platelet counts and various rotational thromboelastometry (ROTEM) parameters.ResultsThe inclusion criteria for patients diagnosed with acute, persistent, and chronic ITP were platelet counts of <30 × 10⁹/L and no clinically significant bleeding (grade ≥ 2 according to the WHO Bleeding Scale) at the beginning of the study. After 24 hours of follow-up, of the 45 enrolled patients, 14 (31.1%) experienced clinically significant bleeding. The mean platelet counts of patients with and without clinically significant bleeding were not statistically different (p = .09). However, the mean EXTEM maximum clot firmness (MCF), EXTEM A10, EXTEM area under the curve (AUC), and platelet maximum clot elasticity (MCE) values of the two groups were statistically different (p < .05). There was also a significant difference in IPF values between these two groups (p < .05.)ConclusionResults obtained from this preliminary study demonstrate that ROTEM parameters might be useful in predicting factors for hemorrhage in ITP patients. Future studies with a larger sample size is warranted to confirm our findings, which will allow prompt and effective bleeding management in ITP patients.