Immune thrombocytopenic purpura in adults:

A Review on Romiplostim Mechanism of Action and the Expressive Approach in E. coli

Immune thrombocytopenic purpura (ITP) is an autoimmune disorder determined by immune-mediated platelet demolition and reduction of platelet production. Romiplostim is a new thrombopoiesis motivating peptibody that binds and stimulates the human thrombopoietin receptor the patent of which was registered in 2008. It is used to treat thrombocytopenia in patients with chronic immune thrombocytopenic purpura. Romiplostim is a 60 kDa peptibody designed to inhibit cross-reacting immune responses. It consists of four high-affinity TPO-receptor binding domains for the Mpl receptor and one human IgG1 Fc domain. Escherichia coli is a good host for the fabrication of recombinant proteins such as romiplostim. The expression of a gene intended in E. coli is dependent on many factors such as a protein's inherent ability to fold, mRNA's secondary structure, its solubility, its toxicity preferential codon use, and its need for post-translational modification (PTM). This review focuses on the structure, function, mechanism of action, and expressive approach to romiplostim in E. coli.

Immune globulin therapy and kidney disease: Overview and screening, monitoring, and management recommendations

Purpose

This report calls attention to the potential risks of diminished kidney function when administering immune globulin (IG). The goal is to increase awareness of chronic kidney disease (CKD) and kidney function impairment in patients receiving IG and provide recommendations for screening, monitoring, and management to promote risk prevention and mitigation.

Summary

Human IG preparations for intravenous (IVIG) or subcutaneous (SCIG) administration are the mainstay of treatment in patients with primary immunodeficiency diseases. Increasingly, IVIG at high doses (1,000 to 2,400 mg/kg) is also used as a treatment for a variety of autoimmune and inflammatory conditions. Although some autoinflammatory disorders respond to a single course of IVIG therapy, the majority of patients require long-term, regular infusions, thereby increasing the overall risks. Often, both patients and physicians treating adults with IG are unaware of underlying CKD or kidney function impairment. This lack of awareness constitutes a major risk factor for potential worsening, particularly when using high doses of IVIG. Therefore, screening of all patients for CKD and kidney function impairment before the use of IG is essential. Identification of the cause of kidney impairment is strongly encouraged, as IG therapy may need to be modified.

Conclusion

As detailed here, there are potential risks to patients with impaired kidney function with administration of IG, particularly at high doses. Product selection, volume, route of administration, and rate of infusion may impact those with compromised kidney function. Therefore, screening of all patients for CKD and kidney function impairment before the use of IVIG and SCIG, as well as ongoing monitoring and management, is critical. As with all potential adverse drug reactions, the best approach is to prevent them.

Idiopathic thrombocytopenic purpura (ITP) - new era for an old disease

Immune thrombocytopenia is an autoimmune hematological disorder characterized by severely decreased platelet count of peripheral cause: platelet destruction via antiplatelet antibodies which may also affect marrow megakaryocytes. Patients may present in critical situations, with cutaneous and/or mucous bleeding and possibly life-threatening organ hemorrhages (cerebral, digestive, etc.) Therefore, rapid diagnosis and therapeutic intervention are mandatory. Corticotherapy represents the first treatment option, but as in any autoimmune disorder, there is a high risk of relapse. Second line therapy options include: intravenous immunoglobulins, thrombopoietin receptor agonists, rituximab or immunosuppression, but their benefit is usually temporary. Moreover, the disease generally affects young people who need repeated and prolonged treatment and hospitalization and therefore, it is preferred to choose a long term effect therapy. Splenectomy - removal of the site of platelet destruction - represents an effective and stable treatment, with 70-80% response rate and low complications incidence. A challenging situation is the association of ITP with pregnancy, which further increases the risk due to the immunodeficiency of pregnancy, major dangers of bleeding, vital risks for mother and fetus, potential risks of medication, necessity of prompt intervention in the setting of specific obstetrical situations - delivery, pregnancy loss, obstetrical complications, etc. We present an updated review of the current clinical and laboratory data, as well as a detailed analysis of the available therapeutic options with their benefits and risks, and also particular associations (pregnancy, relapsed and refractory disease, emergency treatment).

Second-line treatments in children with immune thrombocytopenia: Effect on platelet count and patient-centered outcomes

Immune thrombocytopenia (ITP) is an autoimmune bleeding disorder with isolated thrombocytopenia and hemorrhagic risk. While many children with ITP can be safely observed, treatments are often needed for various reasons, including to decrease bleeding, or to improve health related quality of life (HRQoL). There are a number of available second-line treatments, including rituximab, thrombopoietin-receptor agonists, oral immunosuppressive agents, and splenectomy, but data comparing treatment outcomes are lacking. ICON1 is a prospective, multi-center, observational study of 120 children starting second-line treatments for ITP designed to compare treatment outcomes including platelet count, bleeding, and HRQoL utilizing the Kids ITP Tool (KIT). While all treatments resulted in increased platelet counts, romiplostim had the most pronounced effect at 6 months (P = .04). Only patients on romiplostim and rituximab had a significant reduction in both skin-related (84% to 48%, P = .01 and 81% to 43%, P = .004) and non-skin-related bleeding symptoms (58% to 14%, P = .0001 and 54% to 17%, P = .0006) after 1 month of treatment. HRQoL significantly improved on all treatments. However, only patients treated with eltrombopag had a median improvement in KIT scores at 1 month that met the minimal important difference (MID). Bleeding, platelet count, and HRQoL improved in each treatment group, but the extent and timing of the effect varied among treatments. These results are hypothesis generating and help to improve our understanding of the effect of each treatment on specific patient outcomes. Combined with future randomized trials, these findings will help clinicians select the optimal second-line treatment for an individual child with ITP.

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.

Splenectomy for immune thrombocytopenia: down but not out

Splenectomy is an effective therapy for steroid-refractory or dependent immune thrombocytopenia (ITP). With the advent of medical alternatives such as rituximab and thrombopoietin receptor antagonists, the use of splenectomy has declined and is generally reserved for patients that fail multiple medical therapies. Splenectomy removes the primary site of platelet clearance and autoantibody production and offers the highest rate of durable response (50% to 70%) compared with other ITP therapies. However, there are no reliable predictors of splenectomy response, and long-term risks of infection and cardiovascular complications must be considered. Because the long-term efficacy of different second-line medical therapies for ITP have not been directly compared, treatment decisions must be made without supportive evidence. Splenectomy continues to be a reasonable treatment option for many patients, including those with an active lifestyle who desire freedom from medication and monitoring, and patients with fulminant ITP that does not respond well to medical therapy. We try to avoid splenectomy within the first 12 months after ITP diagnosis for most patients to allow for spontaneous or therapy-induced remissions, particularly in older patients who have increased surgical morbidity and lower rates of response, and in young children. Treatment decisions must be individualized based on patients' comorbidities, lifestyles, and preferences. Future research should focus on comparing long-term outcomes of patients treated with different second-line therapies and on developing personalized medicine approaches to identify subsets of patients most likely to respond to splenectomy or other therapeutic approaches.

[Quantity of Treg cells and Th17 cells in spleen of primary immune thrombocytopenic purpura patients]

Objective: To observe the quantity of Treg cells and Th17 cells in spleen of adult primary immune thrombocytopenic purpura (ITP) patients. Methods: 43 ITP cases with splenectomy treatment were enrolled from December 2008 to June 2016 at Union Hospital of Fujian Medical University, including 20 males and 23 females with a median age of 36 (18-76) years. The controls were thirty patients who underwent splenectomy because of pancreatic diseases or splenic impairment, including 21 males and 9 females with a median age of 47 (21-69) years. The quantity and ratio of Treg cells and Th17 cells were examined by immunohistochemistry between ITP patients and controls. Results: ①The quantity of Treg cells in ITP were less than controls[ (11.3±4.7) /mm(2) vs (59.0±15.0) /mm(2), t=-22.894, P<0.001], but Th17 cells were more than controls[ (235.2±69.4) /mm(2) vs (181.1±23.7) /mm(2), t=13.768, P<0.001]. So the ratio of Treg/Th17 in ITP was lower than controls (0.048±0.027 vs 0.328±0.086, t=19.522, P<0.001) . ② The quantity of Treg cells in cases without response after splenectomy were less than cases with response[ (9.5±5.0) /mm(2) vs (11.6±4.7) /mm(2), t=2.723, P=0.010], and there is no statistical differences between the two groups about the quantity of Th17 cells and the ratio of Treg/Th17 cells[ (232.3±80.8) /mm(2) vs (239.6±66.9) /mm(2), t=1.108, P=0.277; 0.040±0.024 vs 0.053±0.027, t=0.540, P=0.592]. Conclusions: There is a significant difference about the quantity of Treg cells and Th17 cells in spleen between ITP patients and healthy controls, and they are relevant to the response after splenectomy.

Thrombopoietin Receptor Agonists Are Often Ineffective in Immune Thrombocytopenia and/or Cause Adverse Reactions: Results from One Hand

BACKGROUND

Eltrombopag and romiplostim are thrombopoietin receptor agonists (TPOs) that have been increasingly used for the treatment of immune thrombocytopenia (ITP). Based on our experience, the incidence of abortive treatment with these drugs and the occurrence of adverse reactions that lead to therapy break-off despite response are higher than has been previously suggested.

METHODS

During the last 8 years, a total of 65 patients were treated with eltrombopag and/or romiplostim at our institute.

RESULTS

36 of a total of 58 patients responded well to eltrombopag. In 12 patients that responded, treatment with eltrombopag was discontinued due to the development of adverse reactions. Eltrombopag was replaced by romiplostim in 23 cases (14 non-responders, 9 patients with adverse reactions). Of these patients, 83% responded to romiplostim. Among all patients treated with romiplostim (n = 32), 75% initially responded; however, 8 of these patients developed adverse reactions. Romiplostim was replaced by eltrombopag in 5 cases (4 due to adverse reactions, 1 non-responsive patient), and only 3 (60%) of these patients were observed to respond to eltrombopag.

CONCLUSION

TPOs often remain ineffective in ITP or result in adverse reactions, which lead to treatment stop or to drug switch. Therefore, alternative treatment options are required.

Vincristine efficacy and safety in treating immune thrombocytopenia: a retrospective study of 35 patients

Although vincristine (VCR) is sometimes prescribed for newly diagnosed immune thrombocytopenia (ITP), its efficacy in refractory ITP and sustained efficacy has yet to be demonstrated. We describe our clinical experience and recommend vincristine's correct place in ITP management. This retrospective study analysed data from 35 patients with newly diagnosed (ND), persistent (P) or chronic (C) ITP treated with VCR. The initial response rate, defined as >30 × 10(9) platelets/L, reached 86% after a median of 7 [interquartile range (IQR) 6-13] days. In ND and P ITP, even when previous therapies were inefficient, initial response was 87.5%, suggesting that this treatment could be used particularly in rescue. Median survival time, without failure or relapse, was 15 months (Kaplan-Meier curve). Predictive factors (univariate analysis) of an initial and long-term response were a small number of prior treatments received. However, at 2 yr, only seven patients had sustained response. Eight (23%) patients experienced adverse events: neuropathy for seven and bowel obstruction for one. Vincristine efficacy in ITP was confirmed, and it could be a good strategy for treating resistant ITP, especially in emergencies. In this era of new therapeutics, VCR deserves to remain on the list of ITP treatments because of its initial efficacy, safety and low cost.

[Current treatment of primary immune thrombocytopenia]

Primary immune thrombocytopenia, also termed immune thrombocytopenic purpura (ITP) is an autoimmune disorder characterized by premature platelet destruction and impaired platelet production. Traditional treatment of ITP has predominantly consisted of immune suppression and/or modulation. However, the understanding of the immune mediated impairment of platelet production has led to the development of new treatments that target the thrombopoietin receptor, promoting formation of megakaryocytes and increasing platelet counts. Best practice for the management of ITP has not yet been established because data from comparative studies are lacking. While some disagreement might still remain among experts concerning therapy (when, who, and how should be treated), in recent years different evidence-based practice guidelines have been published to assist healthcare professionals in the diagnosis and treatment of ITP. This review describes the current treatment landscape of ITP.

Association of autoantibody specificity and response to intravenous immunoglobulin G therapy in immune thrombocytopenia: a multicenter cohort study

BACKGROUND

Immune thrombocytopenia (ITP) is a common autoimmune bleeding disorder, in which platelet glycoprotein (GP)IIb-IIIa and GPIb-IX are the two most frequently targeted autoantigens. Our previous studies in animal models of ITP demonstrated that intravenous immunoglobulin G (IVIG) could protect against anti-GPIIb-IIIa autoantibody-mediated thrombocytopenia but failed to ameliorate ITP induced by most anti-GPIb-IX autoantibodies.

OBJECTIVES

The objective of this human study was to evaluate the association between the specificity of antiplatelet autoantibodies and response to IVIG treatment.

PATIENTS/METHODS

In this retrospective study, a cohort of 156 previously untreated adults with severe ITP who underwent IVIG therapy (0.4 g kg(-1)  day(-1) for 5 days) was analyzed. The primary outcome was response defined as platelet counts of ≥ 30 × 10(9)  L(-1) and a doubling of baseline counts within 7 days of dosing, and an absence of bleeding.

RESULTS AND CONCLUSIONS

Among the 66 patients with anti-GPIb-IX autoantibodies, only 24 (36.4%) achieved a response, as compared with 72 of 90 patients (80.0%) who were negative for anti-GPIb-IX autoantibodies (relative risk 2.2; 95% confidence interval 1.6-3.1). This study found no difference in response between patients with anti-GPIIb-IIIa autoantibodies (61.7%) and those without anti-GPIIb-IIIa autoantibodies (61.3%). Logistic regressions, including main effects and the interaction between these two autoantibodies, showed no influence of anti-GPIIb-IIIa autoantibodies on the effects of anti-GPIb-IX autoantibodies with regard to their association with IVIG response. Thus, in adults with ITP, the presence of anti-GPIb-IX autoantibodies is a predictive factor for poor response to IVIG treatment.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01666795.

Co-stimulation with LPS or Poly I:C markedly enhances the anti-platelet immune response and severity of fetal and neonatal alloimmune thrombocytopenia

Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a life-threatening bleeding disorder caused by maternal antibodies against fetal/neonatal platelets. FNAIT is also linked with miscarriages, although the incidence and mechanisms of fetal death have not been well studied. IntegrinαIIbβ3 (GPIIbIIIa) and the GPIbα complex are major glycoproteins expressed on platelets and are also major antigens targeted in autoimmune thrombocytopenia (ITP), but reported cases of anti-GPIb-mediated FNAIT are rare. Bacterial and viral infections have been causally linked with the pathogenesis of immune-mediated thrombocytopenia (ITP); however, it is unknown whether these infections contribute to the severity of FNAIT. Here, immune responses against platelet antigens were examined by transfusing wild-type (WT) mouse platelets into β3-/- or GPIbα-/- mice. To mimic bacterial or viral infections, lipopolysaccharide (LPS) or polyinosinic:polycytidylic acid (Poly I:C) were injected intraperitoneally following platelet transfusions. The FNAIT model was established by breeding the immunised female mice with WT male mice. We demonstrated for the first time that the platelet GPIbα has lower immunogenicity compared to β3 integrin. Interestingly, co-stimulation with LPS or Poly I:C markedly enhanced the immune response against platelet GPIbα and caused severe pathology of FNAIT (i.e. miscarriages). LPS or Poly I:C also enhanced the immune response against platelet β3 integrin. Our data suggest that bacterial and viral infections facilitate the anti-platelet GPIbα response, which may lead to a severe non-classical FNAIT (i.e. miscarriage but not neonatal bleeding) that has not been adequately reported in humans.

Crosstalk between Platelets and the Immune System: Old Systems with New Discoveries

Platelets are small anucleate cells circulating in the blood. It has been recognized for more than 100 years that platelet adhesion and aggregation at the site of vascular injury are critical events in hemostasis and thrombosis; however, recent studies demonstrated that, in addition to these classic roles, platelets also have important functions in inflammation and the immune response. Platelets contain many proinflammatory molecules and cytokines (e.g., P-selectin, CD40L, IL-1β, etc.), which support leukocyte trafficking, modulate immunoglobulin class switch, and germinal center formation. Platelets express several functional Toll-like receptors (TLRs), such as TLR-2, TLR-4, and TLR-9, which may potentially link innate immunity with thrombosis. Interestingly, platelets also contain multiple anti-inflammatory molecules and cytokines (e.g., transforming growth factor-β and thrombospondin-1). Emerging evidence also suggests that platelets are involved in lymphatic vessel development by directly interacting with lymphatic endothelial cells through C-type lectin-like receptor 2. Besides the active contributions of platelets to the immune system, platelets are passively targeted in several immune-mediated diseases, such as autoimmune thrombocytopenia, infection-associated thrombocytopenia, and fetal and neonatal alloimmune thrombocytopenia. These data suggest that platelets are important immune cells and may contribute to innate and adaptive immunity under both physiological and pathological conditions.

Rituximab-induced interstitial lung disease in a patient with immune thrombocytopenia purpura

We report the case of an 84-year-old man with refractory immune thrombocytopenia purpura (ITP) who was treated with rituximab and subsequently developed severe interstitial lung disease. There has been increasing use of rituximab in the treatment of ITP with success rates of up to 62% in adult patients with recurrent ITP. Interstitial lung disease is a rare but recognised complication of rituximab but has been rarely reported in the setting of ITP.

Bilateral ureteral stones and spontaneous perirenal hematoma in a patient with chronic idiopathic thrombocytopenic purpura

Idiopathic thrombocytopenic purpura (ITP) is an immune thrombocytopenia with a usually benign clinical course. Bleedings are mostly of the mucocutaneous type with mild symptoms. Massive bleedings requiring transfusion are rarely seen, unless the number of platelets decreases to extremely low levels. In this case, bilateral perirenal hematoma and bilateral distal ureteral stones were detected on a non-contrast computed tomography scan of a 57-year-old male patient who developed macroscopic hematuria during his treatment in the clinics of internal medicine because of left flank pain and diffuse petechial rashes all over his body. The patient, who had been receiving chronic ITP treatment for 1 year, had a very low platelet count (4,000/mm(3)). The patient was prescribed bed rest, and his platelet count increased to a safe level for surgical intervention of above 50,000/mm(3) with administration of prednisolone, intravenous immune globulin, and platelet suspension. A stone-free state was achieved after bilateral ureterorenoscopy and pneumatic lithotripsy. A conservative approach was followed for the perirenal hematoma. Upon regression of the perirenal hematoma, the patient was discharged at 9 weeks postoperatively.

How I treat immune thrombocytopenia: the choice between splenectomy or a medical therapy as a second-line treatment

The paradigm for managing primary immune thrombocytopenia (ITP) in adults has changed with the advent of rituximab and thrombopoietin receptor agonists (TPO-RAs) as options for second-line therapy. Splenectomy continues to provide the highest cure rate (60%-70% at 5+ years). Nonetheless, splenectomy is invasive, irreversible, associated with postoperative complications, and its outcome is currently unpredictable, leading some physicians and patients toward postponement and use of alternative approaches. An important predicament is the lack of studies comparing second-line options to splenectomy and to each other. Furthermore, some adults will improve spontaneously within 1-2 years. Rituximab has been given to more than 1 million patients worldwide, is generally well tolerated, and its short-term toxicity is acceptable. In adults with ITP, 40% of patients are complete responders at one year and 20% remain responders at 3-5 years. Newer approaches to using rituximab are under study. TPO-RAs induce platelet counts > 50 000/μL in 60%-90% of adults with ITP, are well-tolerated, and show relatively little short-term toxicity. The fraction of TPO-RA-treated patients who will be treatment-free after 12-24 months of therapy is unknown but likely to be low. As each approach has advantages and disadvantages, treatment needs to be individualized, and patient participation in decision-making is paramount.

A novel approach to the evaluation of bleeding-related episodes in patients with chronic immune thrombocytopenia

OBJECTIVE

In clinical studies of patients with severe thrombocytopenia, rescue treatments are used to prevent or stop bleeding. Estimating risk reductions of bleeding for clinical study medications can be challenging. This study evaluated a new and possibly more accurate way of assessing the effects of a treatment intervention on bleeding-related outcomes. We developed a composite endpoint, termed bleeding-related episodes (BRE).

RESEARCH DESIGN AND METHODS

BREs were assessed in a post-hoc analysis of patients with chronic immune thrombocytopenia (ITP) who participated in two romiplostim, phase 3, placebo-controlled studies. Patients received romiplostim or placebo once weekly for 24 weeks. A BRE was defined as an actual bleeding event and/or the use of rescue medication. In total, 125 patients (41 placebo, 84 romiplostim) with platelet counts <30 K were enrolled.

CLINICAL TRIAL REGISTRATION

NCT00102323/NCT00102336.

RESULTS

The rate of all BREs across all studies was reduced by 56% in patients receiving romiplostim compared with placebo. The rate of BREs using immunoglobulin (IVIg or anti-D Ig) was reduced by 89% in patients receiving romiplostim compared with placebo. BREs were more frequent in both groups at platelet counts <50 × 10(9)/L. Results were similar between splenectomized and nonsplenectomized patients. We believe that prior to the development of this tool, bleeding events were underdiagnosed. The BRE tool allowed the identification of multiple interventions within bleeding episodes, which may have required separate interventions and were therefore considered to be additional BREs.

CONCLUSIONS

In this study, the composite endpoint of a bleeding event and the use of rescue medication within close proximity of the bleeding event appears to be feasible and informative. The BRE tool allows for more precise understanding of the effect of rescue therapies in ITP and has broader applications to future clinical trials where assessment of bleeding risk can be complicated or masked by rescue interventions.

LIMITATIONS

This was a post hoc analysis. The assignment of platelet counts to a BRE was based on the platelet count on the first day of a BRE, which may not reflect the platelet count during the entire episode, and the assignment of platelet counts was based on the estimation required for events that occurred between weekly measurements.

Differences in platelet function in patients with acute myeloid leukemia and myelodysplasia compared to equally thrombocytopenic patients with immune thrombocytopenia

BACKGROUND

Severe thrombocytopenia is a major risk factor for hemorrhage, but platelet function and bleeding risk at low platelet counts are poorly understood, because of the limitations of platelet function testing at very low platelet counts.

OBJECTIVES

To examine and compare platelet function in severely thrombocytopenic patients with acute myeloid leukemia (AML) or myelodysplasia (MDS) with that in patients with immune thrombocytopenia (ITP).

METHODS

Whole blood flow cytometric measurement of platelet activation and platelet reactivity to agonists was correlated with the immature platelet fraction (IPF) and bleeding symptoms.

RESULTS

Patients with AML/MDS had smaller platelets, lower IPF and substantially lower platelet surface expression of activated glycoprotein (GP)IIb-IIIa and GPIb, both with and without addition of ex vivo ADP or thrombin receptor-activating peptide, than patients with ITP. In both ITP and AML/MDS patients, increased platelet surface GPIb on circulating platelets and expression of activated GPIIb-IIIa and GPIb on ex vivo activated platelets correlated with a higher IPF. Whereas platelet reactivity was higher for AML/MDS patients with bleeding than for those with no bleeding, platelet reactivity was lower for ITP patients with bleeding than for those with no bleeding.

CONCLUSIONS

AML/MDS patients have lower in vivo platelet activation and ex vivo platelet reactivity than patients with ITP. The proportion of newly produced platelets correlates with the expression of platelet surface markers of activation. These differences might contribute to differences in bleeding tendency between AML/MDS and ITP patients. This study is the first to define differences in platelet function between AML/MDS patients and ITP patients with equivalent degrees of thrombocytopenia.

Eltrombopag for the treatment of immune thrombocytopenia

Chronic immune thrombocytopenia (ITP) is an autoimmune disorder characterized by a low platelet count that has persisted for more than 12 months. Patients with severe, symptomatic disease may have significant morbidity and require treatment. Historically, the underlying cause of ITP was believed to be accelerated platelet destruction by antiplatelet antibodies. Treatment options were therefore focused on reducing platelet autoantibody production or inhibiting macrophage-mediated platelet destruction. These treatments are not always effective or, at best, only have a transient effect and treatment-related adverse events often preclude their long-term use. Recently, impaired platelet production was observed in many ITP patients. Therefore, growth factor or growth factor analogs that stimulate megakaryopoiesis may be useful in ITP treatment. This article presents data on the pharmacology, clinical efficacy, safety profile and future roles of eltrombopag, an orally bioavailable, low-molecular-weight, synthetic nonpeptide thrombopoietin receptor agonist, in the treatment of ITP.

Comparison of conventional dose steroid treatment and high dose steroid treatment as run-in regime for splenectomy in immune thrombocytopenic purpura (ITP)

BACKGROUND

Splenectomy is a treatment procedure for ITP which is being used for more that 50years and is still considered as the best option for the treatment of the condition. The facts that frequent monitoring is not required and that medical treatment is not indicated following splenectomy in most cases are among the major advantages of the procedure.

AIM OF THE STUDY

To compare the conventional dose steroid and high dose steroid treatments as run-in regime for splenectomy in patients diagnosed with ITP.

METHODS

The conventional dose steroid (1mg/kg, n=20) and high dose steroid treatments (30mg/kg, n=30) were applied to 50 cases with ITP between 1998 and 2008 in our clinic.

RESULTS

High dose steroid produced higher platelet count on days 3, 5, and 7 compared to conventional dose steroid. There were no differences between the groups in terms of adverse effects. Treatments were discontinued after the operation by rapidly reducing the dose. Postoperative values regarding response to splenectomy were comparable in both groups.

CONCLUSIONS

Both higher and earlier responses obtained with high dose steroid may be significant in reducing hospitalization period of patients and eliminating life-threatening platelet values within the shortest time possible.

Infection-related transient loss of response and other early side effects in chronic ITP during treatment with thrombopoietin mimetics

BACKGROUND

The new thrombopoietin mimetics (TM) romiplostim (Nplate®) and eltrombopag (Revolade®) have been demonstrated to increase platelet counts in the majority of patients with chronic autoimmune thrombocytopenia (ITP). Platelet counts in chronic ITP may fluctuate significantly due to infections, but it is unknown if this holds true in patients being treated with TM.

PATIENTS AND METHODS

13 adult patients with refractory chronic ITP were treated with the new TM. 10 patients were only treated with eltrombopag, 2 were initially treated with eltrombopag and subsequently switched to romiplostim, and 1 patient was only treated with romiplostim.

RESULTS

Ten patients responded to eltrombopag, and 4 of these patients experienced a transient loss of response following infection. Two patients developed bleeding symptoms, with 1 of these patients requiring platelet transfusion. All 3 patients treated with romiplostim responded, and 1 of these patients experienced also a transient loss of response following infections.

CONCLUSIONS

Patients receiving treatment with TM may experience adverse platelet count fluctuations during infections.

Long-term outcomes of a 5-year follow up of patients with immune thrombocytopenic purpura after splenectomy

Background

The long-term outcomes of adult patients with immune thrombocytopenic purpura (ITP) after splenectomy are not clear.

Methods

We retrospectively analyzed 31 patients who underwent splenectomy after diagnosis of ITP at our institution between 1990 and 2009. Long-term follow-up was defined as a follow-up that lasted 1 year or more from splenectomy to the last follow-up.

Results

The overall response rate to splenectomy was 84%. However, the response rate at 6 and 12 months decreased to 77% and 68%, respectively. During the 6 years of median follow-up after splenectomy, 11 patients (35%) relapsed. The long-term response rate was 55%. The long-term follow-up of 26 patients after responding to splenectomy showed that the median time from splenectomy to relapse was 19 months in the partial response (PR) group; however, there was no relapse after 9 months in the complete response (CR) group. Variables, including age, were not predictive of the long-term response after splenectomy. Additional treatment in patients who did not respond or relapsed after splenectomy was mostly effective. After a median follow-up of 7 years (range: 1-25 years) from the diagnosis, there were 2 deaths, including one due to spontaneous bleeding after repair of duodenal ulcer perforation.

Conclusion

Although splenectomy is safe and effective, the response rate after splenectomy continuously decreases over time. The duration of response is different between the patients that achieved CR and those that achieved PR. Factors, including age, were not predictors of a response to splenectomy.

Clinical impact and cost of monitoring for asymptomatic laboratory abnormalities among patients receiving antiretroviral therapy in a resource-poor setting

BACKGROUND

Laboratory monitoring for toxicity among patients receiving antiretroviral therapy (ART) in less-developed settings is technically challenging and consumes significant resources.

METHODS

We conducted a cohort study of the 1800 adult patients who initiated ART at the Haitian Study Group for Kaposi's Sarcoma and Opportunistic Infections (GHESKIO) in Haiti from 2003 to 2006, using baseline data to establish the prevalence and using follow-up data to establish the incidence of hepatitis, renal insufficiency, hyperglycemia, anemia, neutropenia, and thrombocytopenia. We determined how frequently routine (not symptom-driven) testing detected significant laboratory abnormalities and calculated the cost per disability-adjusted life year (DALY) averted by detection of these events in the asymptomatic stage, compared with a strategy of symptom-prompted testing only.

RESULTS

Forty-eight patients (3.5%) had severe anemia at baseline testing and consequently did not receive zidovudine. Fifty-three patients receiving zidovudine therapy developed severe anemia during follow-up (incidence, 2.5 cases/100 person-years). Monitoring for asymptomatic anemia with hematocrit testing was cost-saving at baseline and had a cost-effectiveness ratio of US$317/DALY averted during follow-up; with a complete blood count, costs increased to US$1182 and $10,781/DALY averted, respectively. With glucose monitoring, 11 patients were diagnosed with new-onset hyperglycemia during follow-up (incidence, 0.7 cases/100 person-years), resulting in a cost-effectiveness ratio of US$9845 per DALY averted. Monitoring for asymptomatic hepatitis and renal insufficiency was expensive and rarely affected care.

CONCLUSIONS

Resource-poor countries should select which laboratory tests to perform on the basis of the cost-effectiveness of each test. This will depend on the national ART drug regimen and the prevalence of other comorbidities. Routine monitoring with multitest hematological and chemistry panels is unlikely to be cost-effective.

Management of acquired bleeding problems in cancer patients

Cancer patients can have acquired bleeding problems for many reasons. In this review, an approach to the evaluation and management of the bleeding patient is discussed. Specific issues including coagulation defects, thrombocytopenia, platelet dysfunction, and bleeding complications of specific hematological malignancies due to anticoagulation, are discussed.

Treatment practices in adults with chronic immune thrombocytopenia - a European perspective

Immune thrombocytopenia (ITP) is characterised by platelet destruction and impaired production leading to isolated thrombocytopenia. The aim of this study, comprising a retrospective longitudinal cohort study complemented by a Delphi panel of 35 physicians, was to describe standard treatment practices and treating physician's perception and preferences for available treatment options in chronic ITP. The medical records of 610 patients were reviewed over 12 months. Mean age at the start of the observational period was 54.6 yr, median platelet count 77 x 10(9)/L with 41% of patients having symptoms of ITP. Treated patients (61%) received an average of 2.7 medications either for ITP or ITP treatment-related side effects. An array of products was used, but the most frequent were corticosteroids. Delphi panel physicians (45%) indicated the main goals for treatment were to increase platelet levels to at least 30 x 10(9)/L to prevent bleeding or haemorrhage. The majority (89%) indicated that personal experience influenced treatment choice. Most (>80%) rated splenectomy and high-dose corticosteroids as the most effective but were concerned about side effects, and many (75%) would like access to interventions with improved efficacy and safety. The study highlights the need for updated evidence-based treatment guidelines to assist physicians in patient treatment decisions and to realise improvements in patient outcomes. It also identified perceived shortcomings of existing therapies and the need to establish an evidence base for newer interventions that could potentially make lasting response to treatment with fewer adverse effects an achievable goal.

Management of acquired bleeding problems in cancer patients

Cancer patients can have acquired bleeding problems for many reasons. In this review, an approach to the bleeding patient in the Emergency Department is discussed. Specific issue including coagulation defects, thrombocytopenia, platelet dysfunction, bleeding complications of specific hematological malignancies and due to anticoagulation, are discussed.

Romiplostim

*Romiplostim is an Fc-peptide fusion protein (or 'peptibody') that stimulates megakaryopoiesis and thrombopoiesis by binding to, and activating, the thrombopoietin receptor. *Because it has no sequence homology to thrombopoietin, romiplostim theoretically avoids the risk of eliciting cross-reacting, neutralizing antibodies to thrombopoietin. *In well designed, 24-week, phase III trials, subcutaneous romiplostim was significantly more effective than placebo in achieving the primary endpoint of a protocol-defined durable platelet response in nonsplenectomized (61% vs 5%) or splenectomized (38% vs 0%) adults with chronic immune (idiopathic) thrombocytopenic purpura (ITP). *Romiplostim was also significantly more effective than placebo with regard to a number of secondary endpoints, including the proportions of patients with an overall (durable plus transient) platelet response or who required ITP rescue medications. The majority of romiplostim-treated patients receiving concurrent ITP drugs were able to reduce or discontinue these therapies. *Platelet response was maintained by most patients during longer-term treatment with romiplostim for up to 3 or 4 years in an open-label extension study. *Romiplostim was generally well tolerated. Almost all adverse events in the phase III studies were of mild-to-moderate intensity; most were unrelated to treatment. Longer-term treatment with romiplostim had an adverse event profile consistent with that observed in the phase III studies.

New-generation drugs that stimulate platelet production in chronic immune thrombocytopenic purpura

Idiopathic thrombocytopenic purpura is an acquired disease characterised by a low platelet count. Development of autoantibodies is a main cause of the disease. Although many patients have few symptoms, life-threatening bleeding can arise and hence, when platelet counts fall to unacceptable values treatment should be initiated. However, conventional immunosuppressive approaches can fail, perhaps because of the heterogeneous nature of the disease. Newly developed agents that increase platelet production by stimulating megakaryocytes-such as drugs that bind to the thrombopoietin receptor c-MPL-offer an alternative treatment strategy. Although initial thrombopoietin analogues caused adverse immune reactions, second-generation thrombopoietin-receptor agonists that are in late-stage clinical development seem promising. In particular, eltrombopag and romiplostim safely increase and maintain platelet production in patients with refractory disease. However, long-term side-effects are being assessed and the exact role of these agents in the overall treatment strategy of chronic idiopathic thrombocytopenic purpura remains to be established.

New Drug Approvals: Romiplostim Management of Immune Thrombocytopenic Purpura

Objective

To review the pharmacology, pharmacokinetics, efficacy, and safety of romiplostim, the first drug approved for use in patients with immune thrombocytopenic purpura (ITP).

Data Sources

Articles were identified through searches of MEDLINE (1966–January 2009) and International Pharmaceutical Abstracts (1970–January 2009) using the key words romiplostim and AMG 531. Searches were limited to articles published in English. The manufacturer was contacted for additional data.

Study Selection And Data Extraction

Clinical trials and pharmacokinetic data were selected for review.

Data Synthesis

Romiplostim is a second-generation thrombopoietic receptor agonist that exerts its therapeutic effect by stimulating megakaryopoiesis. Subcutaneous therapy results in a dose-dependent increase in platelets; however, interindividual variability exists. Time to peak concentration is approximately 14 hours, and the elimination half-life is approximately 3.5 days (range 1–34). Romiplostim undergoes endothelial recirculation and is eliminated by the reticuloendothelial system. The results of 2 Phase 3, randomized, double-blind, placebo-con trolled trials have demonstrated the efficacy of romiplostim for increasing platelet counts in patients with ITP refractory to other therapies, including splenectomy. Effects on platelets were transient and decreased within 2 weeks of discontinuing the drug. Interim results of an open-label extension study revealed that romiplostim has sustained efficacy and tolerability for up to 156 weeks at a dosage range of 1–17 μg/kg/wk (mean 5.9 ± 3.9). The most common adverse effects include headache, fatigue, epistaxis, and contusion. Romiplostim is also under investigation for treatment of thrombocytopenia associated with myelodysplastic syndrome. The drug must be ordered directly from the manufacturer through a limited access program, and weekly subcutaneous injections are given in the clinic setting.

Conclusions

Romiplostim is effective for the management of ITP in adults refractory to other therapies, including splenectomy.

Severe autoimmune cytopenias in treatment-naive hepatitis C virus infection: clinical description of 16 cases

OBJECTIVE

To describe the prevalence, main characteristics, and treatment of severe autoimmune cytopenias [autoimmune hemolytic anemia (AIHA), autoimmune thrombocytopenic purpura (AITP)] in patients with chronic hepatitis C virus (HCV) infection.

METHODS

Retrospective chart review of patients with chronic HCV infection seen at our institution. Two additional departments contributed eight more patients to assess therapy of HCV-related autoimmune cytopenias.

RESULTS

Eight patients (seven AITP, one AIHA) fulfilled the inclusion criteria in our population of 4345 HCV-infected patients. The number of patients with AITP was much greater than would be expected by chance (P<0.0001). Patients with HCV-related AITP were older and demonstrated more immunological markers than a group of 40 controls. Eight additional patients (six AITP, two Evans syndrome) were included. We only assessed the response for AITP patients because of the single case of AIHA. Patients with AITP had a poor response to initial corticosteroids [one complete response (CR), three partial response (PR), and four failures]. Intravenous immunoglobulins led to transient efficacy in three of four patients. In second-line therapy, five of seven patients responded to splenectomy. Rituximab proved effective in increasing platelets in two patients. Of eight patients treated with antiviral therapy (IFN-alpha+/-ribavirin), five responded (three CR, two PR).

CONCLUSION

AITP occurs more commonly in patients with chronic HCV infection than would be expected by chance. HCV-positive AITP requires a treatment strategy different from that used in HCV-negative AITP. On the basis of the results from our study and a literature analysis, we propose an algorithm for treatment of severe HCV-related autoimmune cytopenias.

Refractory immune thrombocytopenic purpura: current strategies for investigation and management

There is currently no consensus on how best to manage refractory immune thrombocytopenic purpura (ITP). In part, this reflects the need for individualized treatment due to the wide spectrum of patients' requirements and responsiveness to therapies. The objective of this review is to provide a clinically useful guide to current management strategies. This article suggests investigations to identify factors that may exacerbate thrombocytopenia and underlie poor therapeutic responses, and highlights emerging therapies, including the thrombopoietic agents, which are anticipated to dramatically alter the natural history of "refractory" ITP. Morbidity, mortality and heath-related quality of life are also discussed.

Standardization of terminology, definitions and outcome criteria in immune thrombocytopenic purpura of adults and children: report from an international working group

Diagnosis and management of immune thrombocytopenic purpura (ITP) remain largely dependent on clinical expertise and observations more than on evidence derived from clinical trials of high scientific quality. One major obstacle to the implementation of such studies and in producing reliable meta-analyses of existing data is a lack of consensus on standardized critical definitions, outcome criteria, and terminology. Moreover, the demand for comparative clinical trials has dramatically increased since the introduction of new classes of therapeutic agents, such as thrombopoietin receptor agonists, and innovative treatment modalities, such as anti-CD 20 antibodies. To overcome the present heterogeneity, an International Working Group of recognized expert clinicians convened a 2-day structured meeting (the Vicenza Consensus Conference) to define standard terminology and definitions for primary ITP and its different phases and criteria for the grading of severity, and clinically meaningful outcomes and response. These consensus criteria and definitions could be used by investigational clinical trials or cohort studies. Adoption of these recommendations would serve to improve communication among investigators, to enhance comparability among clinical trials, to facilitate meta-analyses and development of therapeutic guidelines, and to provide a standardized framework for regulatory agencies.

Rituximab efficacy and safety in adult splenectomy candidates with chronic immune thrombocytopenic purpura: results of a prospective multicenter phase 2 study

Whether rituximab could effectively and safely avoid splenectomy for adults with chronic immune thrombocytopenic purpura (ITP) remains unresolved. A multicenter, prospective, open-label, single-arm, phase 2 trial was conducted to assess rituximab safety and efficacy in adult splenectomy candidates with chronic ITP. Sixty patients with chronic (>or= 6 months) ITP and platelet counts less than 30 x 10(9)/L received a weekly intravenous infusion of rituximab (375 mg/m(2)) for 4 weeks. All other ITP treatments were stopped. A good response was defined as a platelet count 50 x 10(9)/L or more, with at least a doubling of the initial value at 1 and 2 years after the first rituximab infusion. Patients who required another treatment during follow up were considered nonresponders. Sixteen patients experienced transient side effects that necessitated treatment discontinuation for only 1. Good 1-year responses were obtained in 40% of the patients (24/60 [95% confidence interval: 28%-52%]). At 2 years, 33.3% (20/60 patients) had good responses and 6.7% (4/60) had sustained platelet counts of 30 x 10(9)/L or more without treatment. Thirty-six (60%) patients failed to respond; 25 underwent splenectomy. Based on these results, rituximab was an apparently safe and effective splenectomy-avoiding option in some adults with chronic ITP. This trial is registered at http://clinicaltrials.gov as NCT00225875.

Autoimmune manifestations in common variable immunodeficiency

INTRODUCTION

About 20% of subjects with common variable immune deficiency (CVID) develop an autoimmune complication, most often immune thrombocytopenia or hemolytic anemia. While the pathogenesis of autoreactivity is unknown for CVID subjects in general, and to a greater extent in those with autoimmunity, there is a loss of switched memory B cells.

DISCUSSION

About 7-8% of CVID subjects have mutations in the transmembrane activator and calcium-modulating cyclophilin ligand interactor (TACI), a significant association with this immune defect, although the same mutations may be found in normal relatives and rarely in healthy blood donors. In addition to generalized B cell dysfunction, defective elimination of autoimmune B cells has been demonstrated.