Effectiveness of thrombopoietin-receptor agonists in the treatment of refractory immune thrombocytopenia associated to systemic lupus erythematosus

Catastrophic antiphospholipid syndrome in lupus-associated immune thrombocytopenia treated with eltrombopag A case series and literature review

BACKGROUND

Eltrombopag, a thrombopoietin receptor (TPO-R) agonist, is considered a second-line treatment for patients with refractory immune thrombocytopenia (ITP). Systemic lupus erythematosus (SLE) is frequently associated with ITP. In some cases, thrombocytopenia in SLE patients is attributed to concurrent antiphospholipid antibodies (APLA). Currently, data regarding treatment with TPO-R agonists for ITP in SLE or APLA patients are limited. The incidence of SLE flare or antiphospholipid syndrome while on TPO-R agonists has not been well-studied.

CASES

We report 2 cases of female patients with SLE and concurrent triple positive APLA, without thrombotic events in their medical history, in our rheumatology clinic, who were treated for refractory ITP with eltrombopag. Both developed catastrophic antiphospholipid syndrome a few weeks after beginning treatment with eltrombopag. They were admitted to the intensive care unit and treated with solumedrol, plasmapheresis, anticoagulation and rituximab.

CONCLUSIONS

We describe a severe possible side-effect of eltrombopag as a trigger of catastrophic antiphospholipid syndrome, a rare initial manifestation of antiphospholipid syndrome, in SLE patients with APLA. We suggest that APLA should be tested before initiating eltrombopag in patients with SLE-associated ITP. The safety of this treatment should be considered in these cases.

Systemic lupus erythematosus-complicating immune thrombocytopenia: From pathogenesis to treatment

Immune thrombocytopenia (ITP) is a common hematological manifestation of systemic lupus erythematosus (SLE). The heterogeneity of its clinical characteristics and therapeutic responses reflects a complex pathogenesis. A better understanding of its pathophysiological mechanisms and employing an optimal treatment regimen is therefore important to improve the response rate and prognosis, and avoid unwanted outcomes. Besides glucocorticoids, traditional immunosuppressants (i.e. cyclosporine, mycophenolate mofetil) and intravenous immunoglobulins, new therapies are emerging and promising for the treatment of intractable SLE-ITP, such as thrombopoietin receptor agonists (TPO-RAs), platelet desialylation inhibitors(i.e. oseltamivir), B-cell targeting therapy(i.e. rituximab, belimumab), neonatal Fc receptor(FcRn) inhibitor, spleen tyrosine kinase(Syk) inhibitor and Bruton tyrosine kinase(BTK) inhibitor et al., although more rigorous randomized controlled trials are needed to substantiate their efficacy. In this review, we update our current knowledge on the pathogenesis and treatment of SLE-ITP.

Eltrombopag for the treatment of refractory thrombocytopenia associated with connective tissue disease

To assess the efficacy and safety of eltrombopag in connective tissue disease (CTD)-immune thrombocytopenia (ITP), we conducted this single-center retrospective observational study, including patients with refractory CTD-ITP who were treated with eltrombopag between January 2018 and August 2019. The characteristics of patients at baseline, and the efficacy and safety of the drug were analyzed. The predictors for a response were analyzed using a univariate analysis such as Chi-square or nonparametric test and a multiple correspondence analysis (MCA) method. A total of 15 patients with refractory CTD-ITP were included in the study. Their median age at the time of inclusion was 40.6 years. The median platelet count at initiation of eltrombopag was 11.53 × 10⁹/L. The median remission time was 3.42 weeks. The complete remission (CR) and overall response rate decreased with time. The factors that associated with response to eltrombopag in patients with CTD-ITP were protopathy, WBC counts, levels of hemoglobin, and characteristics of bone marrow findings in univariate analysis. In addition, MCA indicated that a poor response to eltrombopag in patients with refractory CTD-ITP was closely associated with a protopathy with SS, medium to severe degree of anemia, leukopenia, and bone marrow aspiration showing aplastic anemia, an absence of megakaryocytes or macrophage activation syndrome (MAS). In conclusion, eltrombopag was effective and well-tolerated in patients with CTD-associated thrombocytopenia. Some factors should be considered in the use of eltrombopag, including the protopathy, blood test, and bone marrow histology.

Therapeutic peptides for the treatment of systemic lupus erythematosus: a place in therapy

INTRODUCTION

Studies in vitro and in vivo have identified several peptides that are potentially useful in treating systemic lupus erythematosus (SLE). The rationale for their use lies in the cost-effective production, high potency, target selectivity, low toxicity, and a peculiar mechanism of action that is mainly based on the induction of immune tolerance. Three therapeutic peptides have entered clinical development, but they have yielded disappointing results. However, some subsets of patients, such as those with the positivity of anti-dsDNA antibodies, appear more likely to respond to these medications.

AREAS COVERED

This review evaluates the potential use of therapeutic peptides for SLE and gives an opinion on how they may offer advantages for SLE treatment.

EXPERT OPINION

Given their acceptable safety profile, therapeutic peptides could be added to agents traditionally used to treat SLE and this may offer a synergistic and drug-sparing effect, especially in selected patient populations. Moreover, they could temporarily be utilized to manage SLE flares, or be administered as a vaccine in subjects at risk. Efforts to ameliorate bioavailability, increase the half-life and prevent immunogenicity are ongoing. The formulation of hybrid compounds, like peptibodies or peptidomimetic small molecules, is expected to yield renewed treatments with a better pharmacologic profile and increased efficacy.

Cryptic conspirators: a conversation about thrombocytopenia and antiphospholipid syndrome

Purpose of review

Although antiphospholipid syndrome (APS) is best known for conveying increased risk of thrombotic events and pregnancy morbidity, thrombocytopenia is also recognized as a common association. In this review, we will explore the relationship between thrombocytopenia and APS, highlighting our evolving understanding – and persistent knowledge gaps – through clinically oriented questions and answers.

Recent findings

A history of thrombocytopenia likely portends a more severe APS phenotype (including increased risk of thrombosis). Although the pathophysiology underlying thrombocytopenia in APS has yet to be definitively revealed, mechanisms that play a role (at least in subsets of patients) include: immune thrombocytopenic purpura/ITP-like autoantibodies against platelet glycoproteins; antiphospholipid antibody (aPL)-mediated platelet activation and consumption; and potentially life threatening thrombotic microangiopathy. Although thrombocytopenia is often ‘mild’ in APS (and therefore, may not require specific therapy), there are causes of acute-onset thrombocytopenia that mandate emergent work-up and treatment. When APS-related thrombocytopenia does require therapy, the approach must be individualized (requiring an understanding of pathophysiology in the particular APS patient). For patients with ITP-like disease, rituximab is emerging as a popular approach to treatment; in contrast, there are hints that thrombopoietin mimetics may be associated with elevated thrombotic risk.

Summary

Thrombocytopenia is common in APS, and is likely associated with more severe disease. Improved understanding of thrombocytopenia in APS has the potential to improve risk stratification, reveal novel aspects of APS pathophysiology, and lead to treatments that are more individualized and holistic.

Use of eltrombopag for patients 65 years old or older with immune thrombocytopenia

BACKGROUND

Eltrombopag is useful for immune thrombocytopenia (ITP). However, results of clinical trials may not accurately mirror clinical practice reality. Here we evaluated eltrombopag for primary and secondary ITP in our ≥65-year-old population.

METHODS

A total of 106 primary ITP patients (16 with newly diagnosed ITP, 16 with persistent ITP, and 74 with chronic ITP) and 39 secondary ITP patients (20 with ITP secondary to immune disorders, 7 with ITP secondary to infectious diseases, and 12 with ITP secondary to lymphoproliferative disorders [LPD]) were retrospectively evaluated.

RESULTS

Median age of our cohort was 76 (interquartile range, IQR, 70-81) years. 75.9% of patients yielded a platelet response including 66.2% complete responders. Median time to platelet response was 14 (IQR, 8-21) days. Median time on response was 320 (IQR, 147-526) days. Sixty-three adverse events (AEs), mainly grade 1-2, occurred. The most common were hepatobiliary laboratory abnormalities (HBLAs) and headaches. One transient ischemic attack in a newly diagnosed ITP and two self-limited pulmonary embolisms in secondary ITP were the only thrombotic events observed.

CONCLUSION

Eltrombopag showed efficacy and safety in ITP patients aged ≥65 years with primary and secondary ITP. However, efficacy results in LPD-ITP were poor. A relatively high number of deaths were observed.

Autoimmune haemolytic anaemia and autoimmune thrombocytopenia in childhood-onset systemic lupus erythematosus: updates on pathogenesis and treatment

PURPOSE OF REVIEW

Autoimmune haemolytic anaemia (AIHA) and autoimmune thrombocytopenia are common complications of childhood-onset lupus, which may be life-threatening. A greater understanding of the pathogenesis of these haematologic manifestations will enhance our understanding of the biology of systemic lupus erythematosus (SLE) and inform the identification of novel treatments.

RECENT FINDINGS

The mechanisms underlying AIHA and autoimmune thrombocytopenia are incompletely understood and likely multifactorial. Although the development of auto-antibodies is central to the disease process, recent studies have demonstrated the importance of cytokines in the underlying pathologic process. In-vitro and in-vivo evidence points to a role for IL17 in the pathogenesis of AIHA, which involves loss of tolerance to red cell auto-antigens and the development of autoantibodies. Sirolimus, an mTor inhibitor, has benefited patients with primary autoimmune cytopenias, possibly by stimulating T regulatory cells, and may also have efficacy for SLE-associated cytopenias. Similarly, low-dose recombinant human IL-2 therapy has shown promising results for improving platelet counts in patients with autoimmune thrombocytopenia, possibly by restoring the balance between T regulatory, T helper and Th17 cells.

SUMMARY

The emergence of new agents directed at restoring immune dysregulation hold promise for the treatment of AIHA and autoimmune thrombocytopenia and should provide better tolerated alternatives to high-dose corticosteroids.

Eltrombopag Improves Refractory Thrombocytopenia in a Patient with Systemic Lupus Erythematosus

A 42-year-old woman with systemic lupus erythematosus (SLE) was admitted to our hospital for evaluation of severe thrombocytopenia. She was treated with steroids, intravenous cyclophosphamide, intravenous immunoglobulin, and plasma exchange, but her thrombocytopenia did not improve. Renal biopsy showed class IV-S(C) + V lupus nephritis, according to the classification of the International Society of Nephrology/Renal Pathology Society. The PA-IgG and serum thrombopoietin (TPO) levels were elevated. Her thrombocytopenia responded to off-label administration of eltrombopag, which was discontinued after 42 months. At 18 months after stopping eltrombopag, the platelet count was 19.3 × 10⁴/μL. Eltrombopag may be a therapeutic option for SLE patients with severe thrombocytopenia refractory to conventional therapy.

Safety and efficacy of thrombopoeitin mimetics for refractory immune thrombocytopenia purpura in patients with systemic lupus erythematosus or antiphospholipid syndrome: a case series

Background

While thrombopoeitin (TPO) agonists that act to simulate platelet production have been approved for use in steroid-refractory chronic immune thrombocytopenia purpura (ITP), there are few data on the safety and efficacy of these medications in patients with concurrent systemic lupus erythematosus (SLE) or antiphospholipid syndrome (APS). Given that these agents can increase all hematopoietic cell lineages, it is unclear if there is an increased risk for exacerbation of the underlying lymphocyte-driven autoimmune disease in this population.

Case summaries

This case series includes four patients with SLE, one with concurrent APS, who were treated for steroid-refractory ITP with TPO mimetics at the University of Virginia between 2005 and 2015. In three of the four cases the medication was successful in improving platelet counts and preventing bleeding events. In addition, none of the patients experienced thrombosis or worsening of their underlying autoimmune disease.

Conclusions

This case series suggests that TPO mimetics are safe and moderately effective in patients with ITP in the setting of SLE or APS and do not contribute to increased disease activity.

Use of eltrombopag for secondary immune thrombocytopenia in clinical practice

Eltrombopag is a second-line treatment in primary immune thrombocytopenia (ITP). However, its role in secondary ITP is unknown. We evaluated the efficacy and safety of eltrombopag in secondary ITP in daily clinical practice. Eighty-seven secondary ITP patients (46 with ITP secondary to autoimmune syndromes, 23 with ITP secondary to a neoplastic disease subtype: lymphoproliferative disorders [LPDs] and 18 with ITP secondary to viral infections) who had been treated with eltrombopag were retrospectively evaluated. Forty-four patients (38%) had a platelet response, including 40 (35%) with complete responses. Median time to platelet response was 15 days (95% confidence interval, 7-28 days), and was longer in the LPD-ITP group. Platelet response rate was significantly lower in the LPD-ITP than in other groups. However, having achieved response, there were no significant differences between the durable response of the groups. Forty-three patients (49·4%) experienced adverse events (mainly grade 1-2), the commonest being hepatobiliary laboratory abnormalities. There were 10 deaths in this case series, all of which were related to pre-existing medical conditions. In routine clinical practice, eltrombopag is effective and well-tolerated in unselected patients with ITP secondary to both immune and infectious disorders. However, the response rate in LPD-ITP is low.

Bone Marrow Megakaryocytes May Predict Therapeutic Response of Severe Thrombocytopenia in Patients with Systemic Lupus Erythematosus

Objective.

To analyze the predictive value of megakaryocyte counts in bone marrow (BM-MK) for determining the therapeutic response of severe thrombocytopenia (TP) in patients with systemic lupus erythematosus (SLE).

Methods.

Thirty-five patients with SLE with severe TP (platelet count ≤ 50 × 109/l) from the Peking Union Medical College Hospital admitted between 2007 and 2014 with appreciable bone marrow aspiration results were analyzed retrospectively. The associations between therapeutic response and clinical manifestations, laboratory findings including BM-MK counts, were evaluated.

Results.

Seventeen (49%) and 8 (23%) patients achieved a complete response (CR) and a partial response (PR), respectively, and 10 had no response (NR). The BM-MK counts in each group were 102 ± 25 (0–322), 136 ± 48 (2–419), and 28 ± 12 (0–105) per slide, respectively. Significant differences were observed in the counts of BM-MK between patients who achieved a clinical response (CR + PR) and those who did not (NR; p = 0.007). Patients in the NR group exhibited fewer BM-MK compared with those in the CR and PR groups (p = 0.017 and p = 0.006, respectively). A receiver-operation characteristic analysis identified that a cutoff value of BM-MK counts at 20 performed pretty well in discriminating patients with differential responses to immunotherapy, with sensitivity and specificity and area under the curve of 88%, 70%, and 0.798, respectively.

Conclusion.

BM-MK count may serve as a good predicting factor for immunotherapeutic response in patients with SLE with severe TP. Patients with BM-MK counts < 20 per slide tend to exhibit poor clinical response.

Current treatment of antiphospholipid syndrome: lights and shadows

For patients with antiphospholipid syndrome (APS), the consensus is to treat those who develop thrombosis with long-term oral anticoagulation therapy and to prevent obstetric manifestations by use of aspirin and heparin. These recommendations are based on data from randomized controlled trials and observational studies. Despite this body of knowledge, areas of uncertainty regarding the management of APS exist where evidence is scarce or nonexistent. In other words, for a subset of patients the course of management is unclear. Some examples are patients with 'seronegative' APS, those who do not fulfil the formal (clinical or serological) classification criteria for definite APS, and those with recurrent thrombotic events despite optimal anticoagulation. Other challenges include the treatment of clinical manifestations not included in the classification criteria, such as haematologic manifestations (thrombocytopenia and haemolytic anaemia), neurologic manifestations (chorea, myelitis and multiple sclerosis-like lesions), and nephropathy and heart valve disease associated with antiphospholipid antibodies (aPL), as well as the possible withdrawal of anticoagulation treatment in selected cases of thrombotic APS in which assays for aPL become persistently negative. This Review focuses on the current recommendations for thrombotic and obstetric manifestations of APS, as well as the management of difficult cases. Some aspects of treatment, such as secondary prophylaxis of venous thrombosis, are based on strong evidence--the 'lights' of APS treatment. Conversely, other areas, such as the treatment of non-criteria manifestations of APS, are based only on expert consensus or common sense and remain the 'shadows' of APS therapy.