Immune Thrombocytopenia Therapy Research Articles

Efficacy and Safety Results With Rilzabrutinib, an Oral Bruton Tyrosine Kinase Inhibitor, in Patients With Immune Thrombocytopenia: Phase 2 Part B Study.

Current treatments for persistent or chronic immune thrombocytopenia (ITP) are limited by inadequate response, toxicity, and impaired quality of life. The Bruton tyrosine kinase inhibitor rilzabrutinib was evaluated to further characterize safety and durability of platelet response. LUNA2 Part B is a multicenter, phase 1/2 study in adults with ITP (≥ 3 months duration, platelet count < 30 × 109/L) who failed ≥ 1 ITP therapy (NCT03395210, EudraCT 2017-004012-19). Oral rilzabrutinib 400 mg bid was given over 24 weeks, with optional long-term extension (LTE). Primary endpoints were safety and platelet counts ≥ 50 × 109/L on ≥ 8 of the last 12 weeks of main treatment without rescue medication. From 22 March2018 to 31 January2023, 26 patients were enrolled. Patients had baseline median platelet count 13 × 109/L, ITP duration 10.3 years, and six prior ITP therapies (46% splenectomized). Nine (35%) patients achieved the primary endpoint. Platelet counts ≥ 50 × 109/L or ≥ 30 × 109/L and doubling from baseline without rescue therapy were sustained for a mean 9.3 weeks. 11 (42%) LTE-eligible patients were ongoing with median LTE platelet > 80 × 109/L. Three (12%) patients received rescue medication during main treatment, none in LTE. Clinically meaningful improvements were observed in fatigue and women's health. With a median treatment duration of 167 days (main treatment), 16 (62%) patients had ≥ 1 treatment-related adverse event (AE), mainly grade 1, including diarrhea (35%), headache (23%), and nausea (15%). There was no treatment-related grade ≥ 2 bleeding/thrombotic events/infections, serious AE, or death. Rilzabrutinib continues to demonstrate durable platelet responses with favorable safety profile in previously treated ITP patients. Trial Registration: NCT03395210, EudraCT 2017-004012-19.

Management of Adult Patients with Newly Diagnosed or Relapsed Primary Immune Thrombocytopenia in Eastern Austria.

Treatment sequence in primary immune thrombocytopenia (ITP) is based on national and international recommendations, treatment availability, and physician expertise. This article aimed to provide real-world data on treatment sequence and responses to first- and second-line treatments in newly diagnosed and relapsed adult ITP patients. We analyzed a cohort of 46 adult ITP patients from the Vienna ITP Biobank, who started first-line therapy within 1 week before their first study visit between February 2016 and March 2023. We investigated clinical patient characteristics and patient management in our specialized center and examined the impact of the international ASH guidelines on ITP treatment. Forty-six primary ITP patients, 27 (58.7%) with newly diagnosed ITP and 19 (41.3%) with relapsed ITP, were investigated. Most patients were female (65.2%) with a median platelet count of 9 × 109/L, and 31 patients (67.4%) had bleeding symptoms. All patients received first-line treatment with oral prednisolone; 15 patients received oral prednisolone combined with intravenous immunoglobulins (IVIGs), which were more commonly administered in newly diagnosed than in relapsed ITP patients. First-line therapy resulted an overall response in 82.6% of patients after a median (interquartile range [IQR]) time of 10 (5-25) days. There was no difference in treatment responses between newly diagnosed and relapsed ITP patients, but newly diagnosed patients had a shorter time to response (median [IQR]: 8 [5-14] and 14 [8-27], p = 0.02). Twenty-three (50%) of the patients (11/27 newly diagnosed [40.7%], 12/19 relapsed [63.2%]) required second-line ITP therapy. Thrombopoietin-receptor agonists (TPO-RAs) were the most commonly used second-line therapy with a response rate of 73.7%, and a median (IQR) time to treatment response of 15 (12-20) days. Overall response rates to TPO-RA treatment did not differ between newly diagnosed and relapsed ITP. Following the publication of novel guidelines in 2019, the median (IQR) duration of corticosteroid treatment shortened (100-52 days, p = 0.01), as did the time to second-line treatment (160-47 days, p = 0.01), and the median number of first-line therapies decreased from 2 (1-3) to 1 (1-2). Initial treatment with corticosteroids was effective in the majority of newly diagnosed and relapsed ITP. Response rates to initial corticosteroid treatment in ITP patients are consistent with previous data, but only 50% achieve sustained remission. TPO-RAs, which are well tolerated and effective, are the most commonly used second-line therapy in our study population. International guidelines have led to faster treatment transitions and reduced splenectomy rates. Integration of real-life experience, expert consensus, and guidelines optimizes ITP patient management.

Level of CD11a among Newly Diagnosed ITP Patients and after 6 Months Follow Up

Abstract Background and Objectives Immune thrombocytopenia (ITP) is a relatively frequent acquired bleeding disorders. Etiology is not yet well understood. Lymphocytic function associated antigen-1(LFA-1) might play an important role in signal coordination and lymphocyte activation. The aim of this study was to assess CD11a expression on lymphocytes in newly diagnosed ITP patients and to correlate it with bleeding severity in ITP and to evaluate the effect of immunomodulation medications on CD11a expression in children with ITP. Patients and Methods This is a prospective case-control study enrolling children with ITP attending pediatric Hematology clinic, Ain Shams University Hospitals through November 2021-November 2022 and near equal number of age and sex matched control subjects were randomly selected. All necessary laboratory tests for diagnosis of ITP were performed and the expression of CD11a on lymphocytes was analyzed by flow cytometry at the start of the study and after 6 months of follow up and assessment of bleeding manifestations according to ITP- specific bleeding assessment tool (ITP-BAT). Results Thirty-five patients aged (2-15) years with median age 6.5 years. 21 males and 14 females were enrolled as newly diagnosed primary ITP. The mean platelet count in these patients was 13(103/ul) initially and 239(103/ul) at follow up with response rate of 94.1%. The treatment received in ITP patients was corticosteroid (97.1%),IVIG (11.6%),thrombopoietin receptor agonist (17.4%) and anti CD20 monoclonal antibody (5.8%). The mean fluorescence intensity (MFI) of CD11a was 95.7% initially and 94.7 % at follow up and it was 94.3% in the control group. The mean fluorescence intensity (MFI) of CD11a on lymphocytes showed significant difference in ITP patients initially compared to healthy controls (p value= 0.001) and (MFI) of CD11a on lymphocytes show significant difference between patients before and after treatment (p value=0.001). Conclusion CD11a had a possible role in the pathogenesis of ITP. Immune-modulatory therapy for ITP affects the level of CD11a expression on lymphocytes. CD11a expressions on lymphocytes were not correlated with the platelet counts nor the bleeding score in ITP.

Treatment opportunities for refractory immune thrombocytopenia

Background. Primary immune thrombocytopenia (ITP) is an orphan disease characterized by decreased platelet count in the peripheral blood which in some cases can cause bleeding of varying severity. Currently, the use of thrombopoietin receptor agonists (TPO-RAs) is recommended as the second line therapy for ITP as it allows to achieve high platelet response (PR), including complete, in 73 % of cases of chronic ITP and in 87 % of cases of newly diagnosed disease. The mechanism of action differs for different TPO-RAs. Given this fact, in cases of resistance or intolerance to therapy with one TPO-RA, attempts are made to switch to another. The effectiveness of this approach for overcoming ITP resistance varies from 50 to 93 % according to various publications. Aim. To assess the ability to achieve and maintain PR by switching from one TPO-RA to another in cases of resistance to the previous TPO-RA used in the second or subsequent lines of therapy. Materials and methods. The analysis included 59 patients who were resistant (in 2 cases intolerance was also noted) to TPO-RA therapy (received after standard therapy) who were prescribed TPO-RA treatment with a different mechanism of action: switch from romiplostim to eltrombopag (25 patients) or vice versa (34 patients). Both groups were comparable in terms of demographic characteristics and median platelet level at the time of TPO-RA switching. Results. PR was obtained in 76 % of cases, including complete response in 54 %, as a result of switching from one TPO-RA to another in 59 patients. Among 34 patients switched from eltrombopag to romiplostim, PR was achieved in 31 (91 %) patients, including complete response in 22 (65 %). Romiplostim was switched to eltrombopag in 25 patients, PR was achieved in 14 (56 %) with complete response in 10 (40 %). Conclusion. The study showed that PR can be achieved and maintained through switching from one TPO-RA to an alternative.

Platelet response to romiplostim amongst patients with newly diagnosed, persistent, and chronic immune thrombocytopenia in routine clinical practice in Denmark, Sweden, and Norway.

Patient characteristics and platelet responses at romiplostim initiation according to the duration of immune thrombocytopenia (ITP) are poorly understood. Amongst romiplostim-exposed adults with ITP lasting ≥6 months during 2009-2018 in Denmark, Sweden, and Norway, we examined characteristics at romiplostim initiation, romiplostim dosage, and durable platelet response (≥75% of measurements ≥50 × 109/L at 14-24 weeks) for subcohorts with newly diagnosed (duration <3 months), persistent (3-12 months), or chronic (>12 months) ITP initiating romiplostim. The 285 romiplostim initiators comprised 81 (28%) with newly diagnosed, 47 (16%) with persistent, and 157 (55%) with chronic ITP. More patients with newly diagnosed ITP than longer ITP duration, had low comorbidity levels, two or more prior ITP therapies, and previous bleeding requiring hospitalisation. The median romiplostim doses were similar across subcohorts. During treatment, median platelet counts were similar across subcohorts (75-76 × 109/L), and the durable platelet response was 64.6%, 52.9%, and 52.7% for newly diagnosed, persistent, and chronic ITP, respectively. After treatment cessation, the median platelet count was 138 × 109/L, 68 × 109/L, and 71 × 109/L, respectively. In conclusion, newly diagnosed patients, compared with romiplostim initiators with longer disease duration, had more severe ITP, higher frequency of durable platelet response, and higher median platelet count after cessation.

Differential diagnosis and therapy of immune thrombocytopenia

Immune thrombocytopenia is caused by autoantibodies against surface antigens on platelets. Since only about 50 % of cases will allow the identification of glycoprotein-specific antibodies, ITP remains a diagnosis of exclusion. Apart from EDTA-induced pseudo thrombocytopenia, other diseases like secondary thrombocytopenia due to medication, a large number of other disease and hereditary thrombocytopenias must be taken into account. The first-line therapy of ITP includes corticosteroids and intravenous immunoglobulins. The second line consists of thrombopoietin receptor agonists, rituximab, or splenectomy. For further lines of therapy, Fostamatinib and non-steroidal immunosuppressives are available.

The role of platelet desialylation as a biomarker in primary immune thrombocytopenia: mechanisms and therapeutic perspectives.

Primary immune thrombocytopenia (ITP) is an acquired autoimmune disorder characterized by the destruction of platelets. Although it was long believed that the critical role of autoantibodies in platelet destruction, primarily through the Fc-dependent platelet clearance pathway, recent findings indicate that the significance of the Fc-independent platelet clearance pathway mediated by hepatocytes, thus shedding light on a previously obscure aspect of ITP pathogenesis. Within this context, the desialylation of platelets has emerged as a pivotal biochemical marker. Consequently, targeting platelet desialylation emerges as a novel therapeutic strategy in the pathogenesis of ITP. Notably, prevailing research has largely focused on antiplatelet antibodies and the glycosylation-associated mechanisms of platelet clearance, while comprehensive analysis of platelet desialylation remains scant. In response, we retrospectively discuss the historical progression, inducing factors, generation process, and molecular regulatory mechanisms underlying platelet desialylation in ITP pathogenesis. By systematically evaluating the most recent research findings, we contribute to a comprehensive understanding of the intricate processes involved. Moreover, our manuscript delves into the potential application of desialylation regulatory strategies in ITP therapy, heralding novel therapeutic avenues. In conclusion, this manuscript not only fills a critical void in existing literature but also paves the way for future research by establishing a systematic theoretical framework. By inspiring new research ideas and offering insights into the development of new therapeutic strategies and targeted drugs, our study is poised to significantly advance the clinical management of ITP.

Real-world experience with fostamatinib in patients with immune thrombocytopenia: Results of an observational study (FORTE).

e23289 Background: Immune thrombocytopenia (ITP) is an autoantibody-mediated disease in which platelets are prematurely phagocytosed by Fcg-receptor-bearing macrophages in a spleen tyrosine kinase (SYK)-dependent signaling pathway. Corticosteroids (CS) are used to suppress the immune response, but long-term use carries a heavy burden of toxicity. Subsequent treatments for ITP include fostamatinib, a potent oral SYK inhibitor approved in 2018 based on two randomized, placebo-controlled, phase 3 trials. In trial patients, who received fostamatinib as second-line therapy following CS with or without immunoglobulins (IVIG), 25 of 32 (78%) patients achieved a platelet response of ≥50,000/µL, which was sustained for a median of 83% of treatment days. Here, we report real-world experience with fostamatinib as second-line therapy for ITP from a multi-center, prospective, observational study. Methods: The study (FORTE; NCT04904276) enrolled adult patients with ITP and an insufficient response to prior CS and/or IVIG. Patients were treated according to their clinician’s discretion, and data were collected for up to 12 months at clinic visits. Results: Sixteen patients were enrolled, and 15 were treated. Of the 15, 9 (60%) were female and the median age was 48 years (range, 20-92). 12 (80%) patients had prior CS and 6 (40%) prior IVIG. 7 (47%) patients completed the study and 8 discontinued treatment due to adverse events (4), lack of efficacy (2), and patient decision (2). After initiation of fostamatinib, 93% (14/15) of patients achieved ≥1 platelet count ≥50,000/μL. Median platelet count increased over time from 43,000/μL (IQR 19,000-105,000) at baseline to 167,000/μL (IQR 96,000-180,000) at Month 12. The median cumulative duration of elevated platelet count was 32 weeks (IQR 6.4-49.4). Concomitant CS were used by 7 (47%) patients at baseline, all of whom were able to taper as early as Month 1 and discontinue their dose by Month 3 in 4 patients, Month 6 in 2 patients, and Month 9 in 1 patient. Five patients had ITP-related AEs (4 Grade 1 and 1 Grade 2): gingival bleeding (2), mucosal haemorrhage (2), fatigue (1), contusion (3), headache (1) and epistaxis (1). There were 3 serious AEs in 2 patients: Grade 3 diarrhea in 1 and Grade 2 dyspnea and chills in 1. Overall safety results were consistent with previous studies of fostamatinib. Conclusions: Real world use of fostamatinib as documented in this observational study demonstrated efficacy and safety as second-line therapy for ITP. Fostamatinib allowed successful tapering and discontinuation of CS while maintaining platelet counts above 50,000/μL. Clinical trial information: NCT04904276 .

Romiplostim use in immune thrombocytopenia: Experience in Cuenca, Ecuador

Introduction. The international consensus and the American Society of Hematology guidelines from 2019 established thrombopoietin analogues as the second-line therapy for primary immune thrombocytopenia cases. Objectives. To describe romiplostim usefulness in patients with immune thrombocytopenia in a third-level hospital in Cuenca, Ecuador. Materials and methods. We conducted a descriptive and retrospective study in patients with immune thrombocytopenia treated with romiplostim. We evaluated the following variables: age, gender, previous therapies to romiplostim, dose, frequency, complications, change of thrombopoietin analogue, and treatment discontinuation. Results. We included 21 patients with immune thrombocytopenia treated with romiplostim, with a median age of 49 years. All patients received corticosteroids as first-line treatment. Three patients required longer administration intervals (over a week), with weekly doses lower than those recommended (< 1 μg/kg). Due to lack of efficacy, six patients replaced elthrombopag with romiplostim. Of the total, three suffered thrombotic complications: two had portal venous thrombosis, and one had pulmonary thromboembolism; five of the patients discontinued romiplostim scheme without resuming it. Conclusions. Romiplostim constitutes a convenient second-line therapy in immune thrombocytopenia. Despite the small sample size, romiplostim early use can minimize toxicities and infectious risks.

Avatrombopag (Doptelet)

We recommend that Doptelet not be reimbursed by public drug plans for the treatment of thrombocytopenia in adults with chronic immune thrombocytopenia (ITP). Evidence from 1 clinical trial showed that Doptelet improved patients’ platelet counts after 6 months of treatment; however, it is not known whether Doptelet can reduce bleeding occurrence, reduce the use of other therapies for ITP used concomitantly with Doptelet, improve symptoms, or improve health-related quality of life when compared to placebo. In addition, evidence from 1 indirect treatment comparison study showed that the comparative efficacy of Doptelet to other established treatments for chronic ITP remains unknown. Patients identified a need for treatments that can reduce the risk of bleeding and improve their quality of life. However, there was not enough evidence to show that Doptelet would meet this need.

Complications of thrombopoietin receptor agonists therapy in patients with immune thrombocytopenia

Immune thrombocytopenia (ITP) is an autoimmune disease characterized by increased platelet destruction and decreased platelet production. The formation of antibodies to platelet and megakaryocyte glycoproteins plays a major role in the pathophysiology of ITP. All treatment strategies for ITP attempt to increase platelet count and reduce the risk of bleeding complications. Corticosteroids remain the most commonly used first-line therapy for ITP, but their long-term use is limited due to the development of severe complications. Today the new treatment methods including the use of thrombopoietin receptor agonists (TPO-RA) romiplostim, eltrombopag and avatrombopag with a number of advantages over standard therapy are of great interest. These drugs are recommended for use in the second-line therapy and show high efficacy in patients with ITP, particularly in real clinical practice. In most cases TPO-RA provide stable and long-term remission of the disease, allowing you to reduce or discontinue the use of glucocorticosteroids and avoid splenectomy. Many studies of the mechanism of action, efficacy and toxicity of TPO-RA have been performed. the research results significantly expand our knowledge about these agents. This review provides comparative data of the TPO-RA safety and the main aspects of their clinical use. The features of the new drug avatrombopag, recently approved for use in the Russian federation, are described. the overview presents the advantages and limitations of each drug, possible adverse events and methods for their control.

Antagonism of the Platelet-Activating Factor Pathway Mitigates Inflammatory Adverse Events Driven by Anti-erythrocyte Antibody Therapy in Mice.

Immune thrombocytopenia (ITP) is an autoimmune disease characterized by low platelet counts primarily due to antiplatelet autoantibodies. Anti-D is a donor-derived polyclonal Ab against the rhesus D Ag on erythrocytes used to treat ITP. Unfortunately, adverse inflammatory/hypersensitivity reactions and a Food and Drug Administration-issued black box warning have limited its clinical use. This underscores the imperative to understand the inflammatory pathway associated with anti-erythrocyte Ab-based therapies. TER119 is an erythrocyte-specific Ab with anti-D-like therapeutic activity in murine ITP, while also exhibiting a distinct inflammatory signature involving production of CCL2, CCL5, and CXCL9 but not IFN-γ. Therefore, TER119 has been used to elucidate the potential mechanism underlying the adverse inflammatory activity associated with anti-erythrocyte Ab therapy in murine ITP. Prior work has demonstrated that TER119 administration is associated with a dramatic decrease in body temperature and inflammatory cytokine/chemokine production. The work presented in the current study demonstrates that inhibiting the highly inflammatory platelet-activating factor (PAF) pathway with PAF receptor antagonists prevents TER119-driven changes in body temperature and inhibits the production of the CCL2, CCL5, and CXCL9 inflammatory cytokines in CD-1 mice. Phagocytic cells and a functional TER119 Fc region were found to be necessary for TER119-induced body temperature changes and increases in CXCL9 and CCL2. Taken together, this work reveals the novel requirement of the PAF pathway in causing adverse inflammatory activity associated with anti-erythrocyte Ab therapy in a murine model and provides a strategy of mitigating these potential reactions without altering therapeutic activity.

Treatment patterns and outcomes among adults with immune thrombocytopenia receiving pharmaceutical second-line therapies: a retrospective cohort study using administrative claims data

Objectives To describe and compare real-world treatment patterns and clinical outcomes among individuals with immune thrombocytopenia (ITP) receiving second-line therapies (rituximab, romiplostim, or eltrombopag). Methods A retrospective cohort study was conducted using a large administrative claims database (January 2013–May 2020) among continuously enrolled patients ≥18 years prescribed second-line ITP therapies. The index date was the date of the first claim of the study medications. Treatment patterns and outcomes were measured during the 12-month follow-up period. Inverse probability of treatment weighting (IPTW) was used to balance covariates across treatment groups. Multivariable logistic regression was used to compare treatment patterns and bleeding risk outcomes. Results A total of 695 patients were included (rituximab, N = 285; romiplostim, N = 212; eltrombopag, N = 198). After IPTW, all baseline covariates were balanced. Compared to eltrombopag, patients in the rituximab cohort were 57% more likely to receive other ITP therapies (systematic corticosteroids or third-line therapies) during the follow-up period (odds ratio [OR] = 1.571, p = .030). There was no significant difference in the odds of receiving a different second-line therapy or experiencing a bleeding-related episode among three groups (p > .050). Patients in the romiplostim cohort were 69% more likely to receive rescue therapy compared to those in the rituximab cohort (OR = 1.688, p = .025). Conclusion Patients with ITP receiving rituximab were more likely to need other ITP therapies but did not experience higher risk of bleeding compared to those receiving eltrombopag or romiplostim. Benefits, risks, cost-effectiveness, and patient preference should all be considered in optimizing second-line therapy for ITP.

Long-term treatment with rilzabrutinib in patients with immune thrombocytopenia

AbstractImmune thrombocytopenia (ITP) is an autoimmune disease associated with autoantibody-mediated platelet destruction and impaired platelet production, resulting in thrombocytopenia and a predisposition to bleeding. The ongoing, global phase 1/2 study showed that rilzabrutinib, a Bruton tyrosine kinase inhibitor specifically developed to treat autoimmune disorders, could be an efficacious and well-tolerated treatment for ITP. Clinical activity, durability of response, and safety were evaluated in 16 responding patients who continued rilzabrutinib 400 mg twice daily in the long-term extension (LTE) study. At LTE entry, the median platelet count was 87 × 109/L in all patients, 68 × 109/L in those who had rilzabrutinib monotherapy (n = 5), and 156 × 109/L in patients who received concomitant ITP medication (thrombopoietin-receptor agonists and/or corticosteroids, n = 11). At a median duration of treatment of 478 days (range, 303-764), 11 of 16 patients (69%) continued to receive rilzabrutinib. A platelet count of ≥50 × 109/L was reported in 93% of patients for more than half of their monthly visits. The median percentage of LTE weeks with platelet counts ≥30 × 109/L and ≥50 × 109/L was 100% and 88%, respectively. Five patients discontinued concomitant ITP therapy and maintained median platelet counts of 106 × 109/L at 3 to 6 months after stopping concomitant ITP therapy. Adverse events related to treatment were grade 1 or 2 and transient, with no bleeding, thrombotic, or serious adverse events. With continued rilzabrutinib treatment in the LTE, platelet responses were durable and stable over time with no new safety signals. This trial is registered at www.clinicaltrials.gov as #NCT03395210 and www.clinicaltrialsregister.eu as EudraCT 2017-004012-19.

Efficacy and safety of avatrombopag in Chinese children with persistent and chronic primary immune thrombocytopenia: A multicentre observational retrospective study in China.

Avatrombopag (AVA) is a novel thrombopoietin receptor agonist (TPO-RA) that has been recently approved as a second-line therapy for immune thrombocytopenia (ITP) in adults; however, its safety and efficacy data in children are lacking. Here, we demonstrated the efficacy and safety of AVA as second-line therapy in children with ITP. A multicentre, retrospective, observational study was conducted in children with persistent or chronic ITP who did not respond to or relapsed from previous treatment and were treated with AVA for at least 12 weeks between August 2020 and December 2022. The outcomes were the responses (defined as achieving a platelet count ≥30 × 109/L, twofold increase in platelet count from baseline and absence of bleeding), including rapid response within 4 weeks, sustained response at weeks 12 and 24, bleeding control and adverse events (AEs). Thirty-four (18 males) patients with a mean age of 6.3 (range: 1.9-15.3) years were enrolled. The median number of previous treatment types was four (range: 1-6), and 41.2% patients switched from other TPO-RAs. Within 4 weeks, overall response (OR) was achieved in 79.4% patients and complete response (CR, defined as a platelet count ≥100 × 109/L and the absence of bleeding) in 67.7% patients with a median response time of 7 (range: 1-27) days. At 12 weeks, OR was achieved in 88.2%, CR in 76.5% and sustained response in 44% of patients. At 24 weeks, 22/34 (64.7%) patients who achieved a response and were followed up for 24 weeks were evaluated; 12/22 (54.55%) achieved a sustained response. During AVA therapy, median platelet counts increased by week 1 and were maintained throughout the treatment period. The proportion of patients with grade 1-3 bleeding decreased from 52.95% at baseline to 2.94% at 12 weeks, while concomitant ITP medications decreased from 36.47% at baseline to 8.82% at 12 weeks, with only 9 (26.47%) patients receiving rescue therapy 23 times within 12 weeks. There were 61.8% patients with 59 AEs: 29.8% with Common Terminology Criteria for Adverse Events grade 1 and the rest with grade 2. These findings show that AVA could achieve a rapid and sustained response in children with persistent or chronic ITP as a second-line treatment, with good clinical bleeding control and reduction of concomitant ITP therapy, without significant AEs.

Excellent response to treatment with hydroxychloroquine in pediatric patients with SLE-related immune thrombocytopenia.

Pediatric immune thrombocytopenia (ITP) may precede systemic autoimmune disorders. In adolescent patients with ITP, routine screening for systemic lupus erythematosus (SLE) may be performed by testing for antinuclear antibody (ANA) titer. Hydroxychloroquine (HCQ) is a safe and effective immunomodulatory drug in patients with SLE but rarely used in ITP. We analyzed the platelet count response and safety of HCQ in treating pediatric patients with SLE-related ITP. A retrospective study including pediatric patients with ITP and definite or incomplete SLE, who were treated with HCQ during 2010-2021. SLE was defined by ANA titer≥1:160 as measured by immunofluorescence and ≥10 points according to the 2019 EULAR/ACR 2019 classification criteria, while patients with incomplete SLE achieved a score<10. Complete response (CR) of the platelet count was defined as platelet count>100 × 109/L; partial response (PR) as platelet count 30-100 × 109/L and exceeding≥twice baseline counts. Of the 17 patients included (median age 15.5 years; IQR 3.6), 15 (88.2%) were female, 13 had definite SLE, and four had incomplete SLE. HCQ was initiated at a median of 17 months after ITP diagnosis with a median platelet count of 38 × 109/L (IQR 28). At 8weeks, 8 (47.1%) patients responded, including 6 (35.3%) achieving CR. After one year, the overall response was 82.4%, with the remaining patients having stable platelet counts requiring no additional ITP therapy. The response was maintained at a median follow-up of 42 months. No adverse effects to HCQ were noted. Pediatric patients with SLE-related ITP may benefit from treatment with HCQ.

Is Immune Thrombocytopenia and its Treatment Associated with Sarcopenia?

Immune thrombocytopenia (ITP) is defined as an isolated platelet count less than 100 × 109/L in the absence of other causes of thrombocytopenia. Sarcopenia is a body-wide muscular disorder with a progressive nature that leads to reduced mobility, physical disability, falls, and poor quality of life. We aimed to evaluate the frequency of objectively diagnosed sarcopenia in patients with ITP and to determine whether ITP therapies have sarcopenic effects. This prospective study included patients who were followed up with ITP in the hematology outpatient clinic. Patients who had received corticosteroids within 3 months were excluded. The handgrip strength test, appendicular skeletal muscle mass (ASMM), ASMM/height2 value, soft lean mass (SLM), trunk soft lean mass (SLMT), and the 6-min walking speed test were applied for muscular evaluations and physical performance assessment. We included 53 patients (female/male: 73.58%/26.42%). While sarcopenia was not observed in 77.36% of ITP patients, possible sarcopenia was diagnosed in 9.43% and confirmed sarcopenia in 13.21%. Severe sarcopenia was not seen in any of the patients. Loss of muscle strength was observed in 22.64% of patients. SLM was found to be low in 92.45%. Sarcopenia may be more frequent among patients with ITP compared to the population, and it is important to note that 92.45% of patients had low SLM and 54.72% had low SLMT. Eltrombopag therapy might be beneficial as demonstrated by higher SLM, ASMM, and ASMM/height2 values.

Predicting the efficacy of glucocorticoids in pediatric primary immune thrombocytopenia using plasma proteomics.

Primary immune thrombocytopenia (ITP) is the most common acquired autoimmune bleeding disorder among children. While glucocorticoids are the primary first-line treatment for ITP treatment, they prove ineffective in certain patients. The challenge of identifying biomarkers capable of early prediction regarding the response to glucocorticoid therapy in ITP persists. This study aimed to identify ideal biomarkers for predicting glucocorticoid efficacy in patients with ITP using plasma proteomics. A four-dimensional data-independent acquisition approach was performed to determine the differentially expressed proteins in plasma samples collected from glucocorticoid-sensitive (GCS) (n=18) and glucocorticoid-resistant (GCR) (n=17) children with ITP treated with prednisone. The significantly differentially expressed proteins were selected for enzyme-linked immunosorbent assay validation in a cohort conprising 65 samples(30 healthy controls, 18 GCS and 17 GCR children with ITP). Receiver operating characteristics curves, calibration curves, and clinical decision curve analysis were used to determine the diagnostic efficacy of this method. 47 differentially expressed proteins (36 up-regulated and 11 down-regulated) were identified in the GCR group compared with the GCS group. The significantly differentially expressed proteins myosin heavy chain 9 (MYH9) and fetuin B (FETUB) were selected for enzyme-linked immunosorbent assay validation. The validation results were consistent with the proteomics analyses. Compared with the GCS group, the GCR group exhibited a significantly reduced the plasma concentration of MYH9 and elevated the plasma concentration of FETUB. Furthermore, the receiver operating characteristics curves, calibration curves, and clinical decision curve analysis demonstrated good diagnostic efficacy of these validated biomarkers. This study contributes to the establishment of objective biological indicators for precision therapy in children with ITP. More importantly, the proteins MYH9 and FETUB hold potential as a foundation for making informed decisions regarding alternative treatments for drugresistant patients, thereby preventing treatment delays.

Baricitinib in Combination with High-Dose Dexamethasone As First-Line Treatment for Newly Diagnosed Immune Thrombocytopenia: A Prospective, Multicenter, Randomized Trial

Introduction: High-dose dexamethasone is among the standard initial therapeutic options for patients with newly diagnosed immune thrombocytopenia (ITP). Although most patients achieve initial remission, optimal first-line therapy remains a challenge due to the low rates of sustained response and the high incidence of corticosteroid-dependency. Antiplatelet autoantibodies and splenic macrophages play central roles in the pathogenesis of ITP. Baricitinib, a Janus-associated kinase 1/2 (JAK1/2) inhibitor, can inhibit antigen presentation by innate immune cells and subsequent T-cell activation while also alleviating B-cell abnormalities and antibody production. The results of our single-arm pilot study suggested that baricitinib might increase the rate of durable response in patients with steroid-resistant or relapsed ITP (NCT05446831, presented at EHA2023, P1594). Accordingly, we further conducted a randomized, controlled trial to evaluate the efficacy and safety of baricitinib plus high-dose dexamethasone as first-line therapy for adulthood ITP. Methods: This multicenter, open-label, randomized, controlled, phase 2 trial was conducted in 10 different tertiary medical centers in China. Adult patients with newly diagnosed, treatment-naïve, confirmed primary ITP who had a platelet count &amp;lt;30×10⁹/L, or a platelet count &amp;lt;50×10⁹/L with clinically significant bleeding, were eligible for this study. Patients were randomly assigned at a 1:1 ratio to receive baricitinib (2 mg daily for 6 consecutive months) plus high-dose dexamethasone (40 mg daily for 4 consecutive days, repeated in the case of lack of response by Day 10) or high-dose dexamethasone alone. The primary endpoint was durable response at the 6-month follow-up. Efficacy endpoints were analyzed in the intention-to-treat population. Safety profiles were analyzed in all patients receiving at least one dose of study medications. The study protocol was approved by the ethics committee or institutional review board of each participating center and was registered with ClinicalTrials.gov (NCT 05932524). Results: A total of 172 patients were screened, of which 132 patients were eligible for this study. Patients were randomly assigned to receive baricitinib plus high-dose dexamethasone (n=66) or high-dose dexamethasone monotherapy (n=66). Four patients did not receive allocated treatment, leaving 128 patients in the safety analysis set. At the 6-month follow-up, a significantly higher proportion of participants in the baricitinib plus high-dose dexamethasone group (42/66, 63.6%) than in the high-dose dexamethasone monotherapy group (25/66, 37.9%) achieved durable response (OR 2.870, 95% CI 1.416-5.816; p=0.003). Initial response was achieved by 52 (78.8%) patients in the combination group and 47 (71.2%) patients in the monotherapy group. No significant difference was observed in the median time from initial treatment to response between the two groups. Complete response (at any time during the treatment) was achieved by 40 (60.6%) patients in the combination group and 35 (53.0%) patients in the monotherapy group. Patients responding to treatment in the combination group showed significantly longer durations of response than responders in the monotherapy group. Patients in both groups reported significantly improved health-related quality of life. The most common adverse events were infections (15/64, 23.4%) and insomnia (12/64, 18.8%) in the combination group, and insomnia (10/64, 15.6%) and anxiety or mood disorders (9/64, 14.1%) in the monotherapy group. No grade 4 or worse adverse events or treatment-related deaths were reported in either group. No thrombotic events, major adverse cardiovascular events (MACE), treatment-related bleeding or anemia were observed. Treatment discontinuation due to an adverse event was reported in 2 (3.1%) patients in the combination group and 3 (4.7%) patients in the monotherapy group. Conclusions: This is the first study reporting JAK inhibition as a first-line therapy for ITP. Baricitinib at 2 mg daily plus high-dose dexamethasone was well tolerated in patients with newly diagnosed ITP and might contribute to achieving a higher rate of durable response.

Initial Report of Part B Phase 1/2 Efficacy and Safety Results for Bruton Tyrosine Kinase Inhibitor Rilzabrutinib in Patients with Relapsed Immune Thrombocytopenia

Introduction: Rilzabrutinib is a potent oral, reversible Bruton tyrosine kinase inhibitor that can treat hematological autoimmune diseases through multiple putative mechanisms of action: (1) inhibition of B-cell activation, (2) interruption of antibody-coated cell phagocytosis by FcϒR in spleen and liver, and (3) induce sustained anti-inflammatory effects (Langrish J Immunol 2021). Preliminary evidence showed that rilzabrutinib treatment resulted in rapid and durable platelet responses with a favorable safety profile in previously treated patients with immune thrombocytopenia (ITP) as studied in part A of a phase 1/2 clinical study (LUNA 2; Kuter N Engl J Med 2022). This abstract summarizes the results of part B that focused on the durability of response with rilzabrutinib in relapsed ITP patients. Methods: Part B of the multicenter, open-label, phase 1/2 study evaluated the efficacy and safety of rilzabrutinib 400 mg bid in patients with relapsed ITP (NCT03395210). Adult patients aged 18-80 y were eligible with ≥2 baseline platelet counts &amp;lt;30x10 9/L no less than 7 days apart in the 15 days before the first dose. Eligible patients were required to have a past response (achievement of platelet count ≥50x10 9/L) to intravenous immunoglobulin (IVIg)/anti-D or corticosteroid (CS) that was not sustained and failed ≥1 other ITP therapy (that was not IVIg or CS). Stable doses of concomitant CS/thrombopoietin receptor agonists (TPO-RA) were allowed with rilzabrutinib. The primary endpoints for part B were safety and durable platelet response defined as platelet counts ≥50x10 9/L on ≥8 of the last 12 weeks of rilzabrutinib without rescue medication. Patients completing 24 weeks of rilzabrutinib with platelet counts ≥50x10 9/L or ≥30x10 9/L and doubling from baseline in ≥4 of the last 8 weeks of treatment without rescue medication could continue rilzabrutinib in the long-term extension (LTE) period. Results: At baseline, 26 enrolled patients had a median age of 57 y (range, 20-75), 62% were female, and median baseline platelet count was 13x10 9/L (range, 2-24x10 9/L). Patients had a median duration of ITP of 10.3 y (range, 0.7-48.2) and had received a median of 6 prior unique ITP therapies (range, 3-19; 46% splenectomy). Seventeen patients (65%) received concomitant non-rescue CS and/or TPO-RA. Nine patients (35%; 95% CI, 17%-56%) achieved the primary endpoint of durable platelet response. Approximately 25% of patients achieved platelet counts ≥50x10 9/L by day 15 of rilzabrutinib treatment (Figure 1A). In 16 patients who achieved platelet counts ≥50x10 9/L, median time to first platelet count ≥50x10 9/L was 15 days (range, 7-134). Median platelet counts for all patients (responders and non-responders) increased over time, exceeding the platelet count thresholds of 30x10 9/L at day 57 and 50x10 9/L at day 120 (Figure 1B). The mean number of weeks with platelet counts ≥50x10 9/L and/or ≥30x10 9/L and doubling from baseline was both 9.3 weeks (SD, 10.1). Three patients (12%) received rescue medication in the main treatment period. Fifteen patients (58%) completed 24 weeks of rilzabrutinib and 11 (42%) entered the LTE. Over the main treatment period, the median duration of treatment was 167 days (range, 7-169). Sixteen patients (62%) had ≥1 related treatment-emergent adverse event (AE), including 35% diarrhea, 23% headache, and 15% nausea. Most AEs were grade 1 or 2; there was 1 treatment-related AE of grade 3 blood creatinine phosphokinase increase. There was no treatment-related grade ≥2 bleeding/thrombotic events or infections, serious AEs, or deaths. Conclusion: Part B study results were consistent with part A. Rilzabrutinib demonstrated rapid, stable, and durable platelet responses in patients with relapsed ITP, with a favorable safety profile in part B.