Long‐term outcomes of patients treated with rituximab as second‐line treatment for adult immune thrombocytopenia – Follow‐up of the RITP study

Treatment outcomes and adherence to treatment in patients with immune thrombocytopenia in two Ethiopian teaching hospitals: a retrospective cohort study

The treatment of immune thrombocytopenia (ITP) is challenging and treatment outcomes depend on numerous unknown and patient-specific factors. Corticosteroids are the cornerstone of ITP treatment, but they are associated with many side effects. In this retrospective cohort study, treatment outcomes and treatment adherence in patients with ITP were investigated in 214 ITP patients from November 15, 2022 to March 15, 2023. Multinomial regression analysis models were used to identify predictive factors for treatment outcomes. A p value of less than 0.05 was considered statistically significant. Most study participants were female 161 (75.5%), and the majority 172 (80.4%) of them were taking prednisolone only. In terms of treatment adherence, 178 (83.2%) of the study participants adhered well to their ITP medications. The complete response rate at 3 months was 139 (65.0%). Predictive factors for partial response were increased negative impact of ITP on health-related quality of life (AOR = 1.221, 95% CI 1.096-1.360), being treated at Tikur Abessa Sepcialazed Hospital (AOR = 0.431, 95% CI 0.197-0.941) and the presence of heavy menstrual bleeding (AOR = 2.255, 95% CI 0.925-5.497) compared to patients with complete response. Hepatitis B virus-infected ITP patients (AOR = 0.052, 95% CI 0.004-0.621) were also a predictive factor for no response compared to complete response.

Splenic Artery Embolization in a Patient With Intracranial Hemorrhage Due to Refractory Persistent Immune Thrombocytopenia

BACKGROUND

Managing intracranial bleeding in patients with refractory immune thrombocytopenia is difficult.

OBSERVATION

A 16-year-old female refractory to prednisolone, intravenous immunoglobulin, eltrombopag, and cyclosporin exhibited heavy menstrual bleeding requiring packed red blood cell transfusions. Autoimmune antibodies were detected, indicating of lupus, and hydroxychloroquine sulfate was administered. In month 6 following the diagnosis, the patient presented with intracranial hemorrhage. Splenic artery embolization promptly increased platelets, and the patient was discharged without any neurological sequela. In month 5 of embolization, the patient's platelet count continued to exceed 300,000/µL without any medical treatment.

CONCLUSIONS

Splenic artery embolization is a life-saving procedure in refractory immune thrombocytopenia.

Therapeutic Outcomes of High Dose-Dexamethasone versus Prednisolone + Azathioprine, Rituximab, Eltrombopag, and Romiplostim Strategies in Persistent, Chronic, Refractory, and Relapsed Immune Thrombocytopenia Patients

BACKGROUND

Primary immune thrombocytopenia (ITP) is an inflammatory autoimmune disease that can be managed with several treatment options. However, there is a lack of comparative data on the efficacy of these options in different phases of the disease.

AIM OF THE STUDY

This study aimed to evaluate the efficacy of high-dose Dexamethasone (HD-DXM), Prednisolone + Azathioprine, Rituximab, Eltrombopag, and Romiplostim schedules in persistent, chronic refractory or relapsed Egyptian ITP patients with a platelet count ≤30 × 109/L. The primary outcome measure was a sustained increase in platelet counts over 50 × 109/L for an additional 12 months without additional ITP regimens. The study also aimed to identify a suitable treatment regimen with a long remission duration for each phase of ITP.

RESULTS

Prednisolone + Azathioprine was significantly more effective in achieving an overall response in persistent patients than Romiplostim, high-dose Dexamethasone, and Rituximab. (90.9% vs. 66.6, [Odds ratio, OR: 5; confidence interval, CI 95% (0.866-28.86)], 45%, [OR: 0.082, CI 95% (0.015-0.448)] and, 25%, [OR: 30, CI 95% (4.24-211.8)], respectively, p-value < 0.01). Eltrombopag was significantly more effective in achieving a durable response in refractory ITP than HD-DXM, Rituximab, and Prednisolone; (80% compared to 32.2% [OR: 0.119, CI 95% (0.035-0.410)], 22.2% [OR:0.071, CI 95% (0.011-0.455)], and 18.1% [OR: 0.056, CI 95% (0.009-0.342)], respectively, p-value < 0.01).

CONCLUSIONS

Finally, Eltrombopag following HD-DXM showed the highest percentage of patients with complete treatment-free survival times of at least 330 days. These findings could help clinicians choose the most appropriate treatment for their patients with ITP based on the phase of the disease. This trial is registered in clinicaltrials.gov with registration number NCT05861297.

Efficacy and steroid-sparing effect of tacrolimus in patients with autoimmune cytopenia

The aim of this study was to evaluate the efficacy, safety, and steroid-sparing effect of tacrolimus in patients with autoimmune cytopenia, including immune thrombocytopenia (ITP), autoimmune hemolytic anemia (AIHA), and Evans syndrome (ES). Patients in the tacrolimus group were treated with tacrolimus in combination with steroids, and the control group received only steroids. Of the 318 patients finally enrolled, 87 (27.4%) were males, with a median age of 45 (14-90) years. The tacrolimus group comprised 144 patients, including 120 ITP, 19 AIHA, and 5 ES patients, and the control group comprised 174 patients, including 141 ITP, 25 AIHA, and 8 ES patients. The optimal ORR of the tacrolimus group was comparable to that of the control group, and the optimal CRR was higher (p < 0.05). Patients receiving tacrolimus had a decreased relapse rate and prolonged relapse-free survival (p < 0.05) compared with the controls for both the whole cohort and the ITP and AIHA subgroups. Compared with the control group, the tacrolimus group had a lower cumulative steroid dosage and earlier discontinuation of steroids (p < 0.05), which resulted in a decreased incidence of steroid-related adverse events (p < 0.05) although the total side effects were similar between the two groups. Similar drug expenses were observed between the tacrolimus and control groups at the 18-month follow-up. In conclusion, the early addition of tacrolimus had a similar ORR, better CRR, lower relapse rate, and prolonged relapse-free survival compared to steroids alone, with reduced steroid-related adverse events.

High-affinity autoreactive plasma cells disseminate through multiple organs in patients with immune thrombocytopenic purpura

The major therapeutic goal for immune thrombocytopenic purpura (ITP) is to restore normal platelet counts using drugs to promote platelet production or by interfering with mechanisms responsible for platelet destruction. Eighty percent of patients with ITP possess anti–integrin αIIbβ3 IgG autoantibodies that cause platelet opsonization and phagocytosis. The spleen is considered the primary site of autoantibody production by autoreactive B cells and platelet destruction. The immediate failure in approximately 50% of patients to recover a normal platelet count after anti-CD20 rituximab-mediated B cell depletion and splenectomy suggests that autoreactive, rituximab-resistant, IgG-secreting B cells (IgG-SCs) reside in other anatomical compartments. We analyzed more than 3,300 single IgG-SCs from spleen, bone marrow, and/or blood of 27 patients with ITP, revealing high interindividual variability in affinity for αIIbβ3, with variations over 3 logs. IgG-SC dissemination and range of affinities were, however, similar for each patient. Longitudinal analysis of autoreactive IgG-SCs upon treatment with the anti-CD38 mAb daratumumab demonstrated variable outcomes, from complete remission to failure with persistence of high-affinity anti–αIIbβ3 IgG-SCs in the bone marrow. This study demonstrates the existence and dissemination of high-affinity autoreactive plasma cells in multiple anatomical compartments of patients with ITP that may cause the failure of current therapies.

Rilzabrutinib, an Oral BTK Inhibitor, in Immune Thrombocytopenia

BACKGROUND

Rilzabrutinib, an oral, reversible covalent inhibitor of Bruton's tyrosine kinase, may increase platelet counts in patients with immune thrombocytopenia by means of dual mechanisms of action: decreased macrophage (Fcγ receptor)-mediated platelet destruction and reduced production of pathogenic autoantibodies.

METHODS

In an international, adaptive, open-label, dose-finding, phase 1-2 clinical trial, we evaluated rilzabrutinib therapy in previously treated patients with immune thrombocytopenia. We used intrapatient dose escalation of oral rilzabrutinib over a period of 24 weeks; the lowest starting dose was 200 mg once daily, with higher starting doses of 400 mg once daily, 300 mg twice daily, and 400 mg twice daily. The primary end points were safety and platelet response (defined as at least two consecutive platelet counts of ≥50×10³ per cubic millimeter and an increase from baseline of ≥20×10³ per cubic millimeter without the use of rescue medication).

RESULTS

Sixty patients were enrolled. At baseline, the median platelet count was 15×10³ per cubic millimeter, the median duration of disease was 6.3 years, and patients had received a median of four different immune thrombocytopenia therapies previously. All the treatment-related adverse events were of grade 1 or 2 and transient. There were no treatment-related bleeding or thrombotic events of grade 2 or higher. At a median of 167.5 days (range, 4 to 293) of treatment, 24 of 60 patients (40%) overall and 18 of the 45 patients (40%) who had started rilzabrutinib treatment at the highest dose met the primary end point of platelet response. The median time to the first platelet count of at least 50×10³ per cubic millimeter was 11.5 days. Among patients with a primary platelet response, the mean percentage of weeks with a platelet count of at least 50×10³ per cubic millimeter was 65%.

CONCLUSIONS

Rilzabrutinib was active and associated with only low-level toxic effects at all dose levels. The dose of 400 mg twice daily was identified as the dose for further testing. Overall, rilzabrutinib showed a rapid and durable clinical activity that improved with length of treatment. (Funded by Sanofi; ClinicalTrials.gov number, NCT03395210; EudraCT number, 2017-004012-19.).

Management of Adult Patients with Immune Thrombocytopenia (ITP): A Review on Current Guidance and Experience from Clinical Practice

Immune thrombocytopenia (ITP) is an autoimmune process resulting in increased destruction and inadequate production of platelets that can result in bleeding, fatigue, and reduced health-related quality of life. While treatment is not required for many patients with ITP, the occurrence of bleeding manifestations, severe thrombocytopenia, and requirement for invasive procedures are among the reasons necessitating initiation of therapy. Corticosteroids, intravenous immunoglobulin, and anti-RhD immune globulin are typical first-line and rescue treatments, but these agents typically do not result in a durable remission in adult patients. Most patients requiring treatment therefore require subsequent line therapies, such as thrombopoietin receptor agonists (TPO-RAs), rituximab, fostamatinib, splenectomy, or a number of other immunosuppressive agents. In this focused review, we discuss management of adult ITP in the acute and chronic settings.

How I treat primary ITP in adult patients who are unresponsive to or dependent on corticosteroid treatment

Approximately 80% of adult patients with immune thrombocytopenia (ITP) have treatment failure with corticosteroids or become dependent on them and require second-line therapy. Several new and effective therapies have been introduced during the past decade and our understanding of disease burden and its effect on quality of life has expanded. It is now recommended that splenectomy, the standard second-line therapy for decades, be delayed for at least 12 to 24 months, allowing for more patients to achieve remission on medical therapies before considering surgery. It is highly recommended that medical therapies be used that have abundant clinical trial evidence, such as the thrombopoietin receptor agonists (TPO-RAs) rituximab and fostamatinib. Unfortunately, there are no reliable biomarkers that help in treatment selection. These therapeutic medical options have variable efficacy, safety profiles, mechanisms of action, and modes of administration. This enables and mandates an individualized approach to treatment, where patient involvement, preferences and values have become central to the process of choosing the appropriate therapy. Both TPO-RAs and fostamatinib are maintenance therapies, whereas rituximab is given for a limited number of doses. Although the response is usually maintained while receiving a TPO-RA or fostamatinib therapy, half of rituximab responders will no longer respond 1 to 2 years after administration and require retreatment or other therapy.

Primary Immune Thrombocytopenia: Novel Insights into Pathophysiology and Disease Management

Immune thrombocytopenia (ITP) is an autoimmune disorder defined by a significantly reduced number of platelets in blood circulation. Due to low levels of platelets, ITP is associated with frequent bruising and bleeding. Current evidence suggests that low platelet counts in ITP are the result of multiple factors, including impaired thrombopoiesis and variations in immune response leading to platelet destruction during pathological conditions. Patient outcomes as well as clinic presentation of the disease have largely been shown to be case-specific, hinting towards ITP rather being a group of clinical conditions sharing common symptoms. The most frequent characteristics include dysfunction in primary haemostasis and loss of immune tolerance towards platelet as well as megakaryocyte antigens. This heterogeneity in patient population and characteristics make it challenging for the clinicians to choose appropriate therapeutic regimen. Therefore, it is vital to understand the pathomechanisms behind the disease and to consider various factors including patient age, platelet count levels, co-morbidities and patient preferences before initiating therapy. This review summarizes recent developments in the pathophysiology of ITP and provides a comprehensive overview of current therapeutic strategies as well as potential future drugs for the management of ITP.