Rituximab chimeric anti-CD20 monoclonal antibody treatment for adult refractory idiopathic thrombocytopenic purpura

Mycophenolate Mofetil for the Treatment of Warm Autoimmune Haemolytic Anaemia Post-Rituximab Therapy: A Case Series

Background

Warm autoimmune haemolytic anaemia (wAIHA) is an acquired haemolytic disorder most commonly treated with a combination of corticosteroids, rituximab and/or splenectomy. Third-line therapies for refractory cases include immunosuppressive agents. Mycophenolate mofetil is frequently used in these scenarios, although its use is supported by small studies and anecdotal evidence rather than large-scale data.

Case description

We describe three cases of refractory warm autoimmune haemolytic anaemia successfully treated with mycophenolate mofetil. Case 1: A persistent case of autoimmune haemolytic anaemia in a 56-year-old was ultimately managed with mycophenolate mofetil, leading to successful steroid tapering and stable haemoglobin levels without relapse. Case 2: A woman with a complex oncological history, including lymphoma and breast cancer, achieved remission with mycophenolate therapy, maintaining stability post-steroid treatment. Case 3: Mycophenolate proved effective for a 63-year-old with cirrhosis after recurrent autoimmune anaemia and deep vein thrombosis, enabling cessation of steroids and maintaining remission.

Conclusion

Management of this condition can be challenging and balancing the available treatments is crucial to reduce potential complications from long-term therapies that appear to be ineffective. Our case series demonstrates anecdotal experience on successful use of mycophenolate mofetil for complex refractory cases of wAIHA.

LEARNING POINTS

Warm autoimmune haemolytic anaemia can be a challenging condition to manage. Refractory cases that are steroid-dependent can benefit from trialling steroid-sparing agents such as mycophenolate.Anti-CD20 agents such as rituximab can be very effective in refractory cases, however there is a small percentage of patients that might not be responsive to this monoclonal antibody.Autoimmune haemolytic anaemias can be frequently complicated by thrombotic events, and part of the backbone treatment is establishing good thromboprophylaxis.

The many facets of immune-mediated thrombocytopenia: Principles of immunobiology and immunotherapy

Immune thrombocytopenia (ITP) is a rare autoimmune condition, due to peripheral platelet destruction through antibody-dependent cellular phagocytosis, complement-dependent cytotoxicity, cytotoxic T lymphocyte-mediated cytotoxicity, and megakaryopoiesis alteration. This condition may be idiopathic or triggered by drugs, vaccines, infections, cancers, autoimmune disorders and systemic diseases. Recent advances in our understanding of ITP immunobiology support the idea that other forms of thrombocytopenia, for instance, occurring after immunotherapy or cellular therapies, may share a common pathophysiology with possible therapeutic implications. If a decent pipeline of old and new agents is currently deployed for classical ITP, in other more complex immune-mediated thrombocytopenic disorders, clinical management is less harmonized and would deserve further prospective investigations. Here, we seek to provide a fresh overview of pathophysiology and current therapeutical algorithms for adult patients affected by this disorder with specific insights into poorly codified scenarios, including refractory ITP and post-immunotherapy/cellular therapy immune-mediated thrombocytopenia.

Case report: Successful treatment of refractory immune thrombocytopenia in chronic lymphocytic leukaemia with venetoclax monotherapy

In chronic lymphocytic leukaemia (CLL), immune dysregulation is common and can manifest as immune thrombocytopenia (ITP). Corticosteroids are the mainstay for front-line management of CLL-associated ITP. Therapy refractoriness represents a clinical challenge and is an indication to commence CLL-directed treatment, historically with anti-CD20 antibody-based chemoimmunotherapy. There is a small but growing body of evidence supporting the use of Bruton's tyrosine kinase (BTK) inhibitors in this setting, but not the B-cell lymphoma-2 inhibitor, venetoclax. Here, we describe two cases of refractory ITP in patients with CLL who successfully achieved and sustained complete remission with fixed-duration venetoclax monotherapy. Responses were rapid and durable and not explained by the concomitant use of an anti-CD20 antibody. This supports a dual role for single-agent venetoclax in managing active CLL and associated ITP as an alternative to BTK inhibitors and anti-CD20 monoclonals.

Rituximab resistance in ITP and beyond

The pathophysiology of immune thrombocytopenia (ITP) is complex and encompasses innate and adaptive immune responses, as well as megakaryocyte dysfunction. Rituximab is administered in relapsed cases and has the added benefit of inducing treatment-free remission in over 50% of patients. Nevertheless, the responses to this therapy are not long-lasting, and resistance development is frequent. B cells, T cells, and plasma cells play a role in developing resistance. To overcome this resistance, targeting these pathways through splenectomy and novel therapies that target FcγR pathway, FcRn, complement, B cells, plasma cells, and T cells can be useful. This review will summarize the pathogenetic mechanisms implicated in rituximab resistance and examine the potential therapeutic interventions to overcome it. This review will explore the efficacy of established therapies, as well as novel therapeutic approaches and agents currently in development.

Comparison of Response to Rituximab Therapy in Adults with Refractory Symptomatic Immune Thrombocytopenia According to the Presence of Accessory Spleen

No data exist for the association between the presence of accessory spleen after splenectomy and response to rituximab in immune thrombocytopenia (ITP). We investigated the relationship between accessory spleen presence and rituximab response in splenectomized ITP patients. Fifteen chronic refractory ITP patients were included. Four weekly doses of rituximab 375 mg/m² were administered. All patients had undergone splenectomy before rituximab administration. Accessory spleen was detected in 5 of 15 patients (33.3%). Median age at diagnosis was significantly higher in patients with accessory spleen than those without accessory spleen (40 (range 25–68 years) and 26 (range 7–40 years), respectively; p = 0.049). There was a trend for older age at time of rituximab initiation in patients with accessory spleen compared to the other group (median 51 (range 43–75 years) and 42.5 (range 30–60 years), respectively; p = 0.066). Median follow-up duration was 96 months (range 40–98). We demonstrated a significant correlation between accessory spleen presence and older age. Accessory spleen presence correlated with higher platelet and WBC counts. We showed good inverse correlation between presence of accessory spleen and time to early response (ER) to rituximab while the rate of early response (ER), late response (LR), sustained response (SR) and overall response (OR) did not differ with respect to the presence of acessory spleen.

Half-Life Extended Nanobody-Based CD38-Specific Bispecific Killercell Engagers Induce Killing of Multiple Myeloma Cells

CD38 is a target for immunotherapy of multiple myeloma. Llama-derived CD38-specific nanobodies allow easy reformatting into mono-, bi- and multispecific proteins. To evaluate the utility of nanobodies for constructing CD38-specific nanobody-based killer cell engagers (nano-BiKEs), we generated half-life extended nano-BiKEs (HLE-nano-BiKEs) by fusing a CD38-specific nanobody to a CD16-specific nanobody for binding to the Fc-receptor on NK cells and further to an albumin-specific nanobody to extend the half-life in vivo. HLE-nano-BiKEs targeting three different epitopes (E1, E2, E3) of CD38 were expressed in transiently transfected HEK-6E cells. We verified specific and simultaneous binding to CD38 on myeloma cells, CD16 on NK cells, and to albumin. We tested the capacity of these HLE-nano-BiKEs to mediate cytotoxicity against CD38-expressing multiple myeloma cell lines and primary myeloma cells from human bone marrow biopsies in bioluminescence and flowcytometry assays with NK92 cells as effector cells. The results revealed specific time- and dose-dependent cytolysis of CD38+ myeloma cell lines and effective depletion of CD38-expressing multiple myeloma cells from primary human bone marrow samples. Our results demonstrate the efficacy of CD38-specific HLE-nano-BiKEs in vitro and ex vivo, warranting further preclinical evaluation in vivo of their therapeutic potential for the treatment of multiple myeloma.

Single-dose versus low-dose rituximab in corticosteroid-resistant or relapsed ITP: A multicenter, randomized, controlled study

Primary immune thrombocytopenia (ITP) is an autoimmune bleeding disorder, in which rituximab (RTX) induces the best long-term effect among recommended second-line treatments. Nevertheless, the optimal regimen of RTX remains unclear. We herein conducted a prospective, multicenter, open-label, randomized controlled trial to compare the efficacy and safety of RTX at two different dosage regimens in patients with corticosteroid-resistant or relapsed ITP. Recruited patients were randomly assigned (1:1) to receive either RTX at a repeated low dose (100 mg weekly for 4 weeks, LD-RTX) or at a single dose (375 mg/m² , S-RTX). Overall response was achieved in 64.3% of patients who received LD-RTX versus 67.4% of those receiving S-RTX (p = .759). The complete response (CR) rate was 23.8% after LD-RTX and 28.3% after S-RTX (p = .635). In health-related quality of life, S-RTX improved patients' psychological status, quality of life, social activities, and work compared with LD-RTX. Furthermore, S-RTX significantly reduced physician visits without compromising efficacy. Our findings demonstrate that a S-RTX is comparable to LD-RTX in effectiveness and safety for treatment of corticosteroid-resistant or relapsed ITP. The single-dosage regimen optimizes the use of medical resources, improves the cost-effectiveness of RTX, and represents a promising and more convenient replacement for LD-RTX in ITP. This study has been completed and is registered with ClinicalTrials.gov, number NCT03258866.

Immune thrombocytopenia

INTRODUCTION

Primary immune thrombocytopenia (ITP) is an autoimmune disorder characterized by a low platelet count (<100 × 10⁹/L) with an increased risk of bleeding. Recent (2019) guidelines from the International Consensus Report (ICR) expert panel and the American Society of Hematology (ASH) provide updated recommendations for the diagnosis and management of ITP.

AREAS COVERED

The 2019 ICR and ASH guidelines are reviewed, and differences and similarities highlighted. Clinical approaches to the treatment of ITP are discussed, including the role of fostamatinib which is an approved treatment option in adult patients who are refractory to other treatments.

EXPERT OPINION

The 2019 ICR and ASH guidelines reflect recent changes in the management of ITP. Current treatment approaches for ITP are more rational and evidence-based than in the past. Patients should be treated based on their needs rather than on disease stage, and patient-specific outcomes, (e.g. quality of life) should be considered. Whilst corticosteroids are the mainstay of initial ITP treatment their use should be limited. For subsequent treatment, the use of thrombopoietin receptor agonist (TPO-RA) agents, fostamatinib and rituximab in adults is supported by robust evidence. Rituximab and recently approved fostamatinib offer viable alternatives to splenectomy.

Real-world Experience of Rituximab in Immune Thrombocytopenia

Immune thrombocytopenia (ITP) is a relapsing-remitting disease often requiring more than one line of therapy. Rituximab is a recommended second-line therapy, but the real-world data on its efficacy and safety from resource constraint settings is limited. We aimed to analyze the safety and efficacy of rituximab in ITP. This is a single-center, retrospective study. This study was conducted at a tertiary care hospital in Northern India from 2005 to 2019. On audit of medical records, all patients of ITP (n-513) who had received rituximab (n-81) were screened for inclusion. Patients whose response assessment was not possible were excluded. Finally, 66 patients were analyzed using statistical packages of Python v3.7. The cumulative incidence of overall response on day 20 was 30.61%, and day 30 was 51.72%. The median time to response was 28 day (range 21-51 day). Cumulative incidence of complete response was 16.67%, and partial response 37.88%. After a median follow-up of 789 day (range 181-5260 day), the cumulative incidence of relapse was 30.32%, 36.12%, and 56.57% at 1, 2, and 5 years respectively. There was no effect of age, sex, duration of disease, lines of therapy received, and platelet count on either cumulative incidence of overall response or relapse. ANA positivity was significantly related to the better cumulative incidence of overall response (p = 0.012), but not with relapse. Infusion-related reactions were the commonest adverse event noted (n-4, grade ≥ 3 CTCAEv4). Rituximab and its generic version are safe and effective second line agent in ITP with a good overall response and sustained response.

Brief Report: Humoral and cellular immune responses to SARS-CoV-2 infection and vaccination in B cell depleted autoimmune patients

Objective

B cell depletion is an established therapeutic principle in a wide range of autoimmune diseases. However, B cells are also critical for inducing protective immunity after infection and vaccination. We undertook this study to assess humoral and cellular immune responses after infection with or vaccination against SARS–CoV‐2 in patients with B cell depletion and controls who are B cell–competent.

Methods

Antibody responses (tested using enzyme‐linked immunosorbent assay) and T cell responses (tested using interferon‐γ enzyme‐linked immunospot assay) against the SARS–CoV‐2 spike S1 and nucleocapsid proteins were assessed in a limited number of previously infected (n = 6) and vaccinated (n = 8) autoimmune disease patients with B cell depletion, as well as previously infected (n = 30) and vaccinated (n = 30) healthy controls.

Results

As expected, B cell and T cell responses to the nucleocapsid protein were observed only after infection, while respective responses to SARS–CoV‐2 spike S1 were found after both infection and vaccination. A SARS–CoV‐2 antibody response was observed in all vaccinated controls (30 of 30 [100%]) but in none of the vaccinated patients with B cell depletion (0 of 8). In contrast, after SARS–CoV‐2 infection, both the patients with B cell depletion (spike S1, 5 of 6 [83%]; nucleocapsid, 3 of 6 [50%]) and healthy controls (spike S1, 28 of 30 [93%]; nucleocapsid, 28 of 30 [93%]) developed antibodies. T cell responses against the spike S1 and nucleocapsid proteins were found in both infected and vaccinated patients with B cell depletion and in the controls.

Conclusion

These data show that B cell depletion completely blocks humoral but not T cell SARS–CoV‐2 vaccination response. Furthermore, limited humoral immune responses are found after SARS–CoV‐2 infection in patients with B cell depletion.

Safety and Efficacy of B-Cell Depletion with Rituximab for the Treatment of Systemic Sclerosis-associated Pulmonary Arterial Hypertension: A Multicenter, Double-Blind, Randomized, Placebo-controlled Trial

Rationale: Systemic sclerosis (SSc)-pulmonary arterial hypertension (PAH) is one of the most prevalent and deadly forms of PAH. B cells may contribute to SSc pathogenesis. Objectives: We investigated the safety and efficacy of B-cell depletion for SSc-PAH. Methods: In an NIH-sponsored, multicenter, double-blinded, randomized, placebo-controlled, proof-of-concept trial, 57 patients with SSc-PAH on stable-dose standard medical therapy received two infusions of 1,000 mg rituximab or placebo administered 2 weeks apart. The primary outcome measure was the change in 6-minute-walk distance (6MWD) at 24 weeks. Secondary endpoints included safety and invasive hemodynamics. We applied a machine learning approach to predict drug responsiveness. Measurements and Main Results: We randomized 57 subjects from 2010 to 2018. In the primary analysis, using data through Week 24, the adjusted mean change in 6MWD at 24 weeks favored the treatment arm but did not reach statistical significance (23.6 ± 11.1 m vs. 0.5 ± 9.7 m; P = 0.12). Although a negative study, when data through Week 48 were also considered, the estimated change in 6MWD at Week 24 was 25.5 ± 8.8 m for rituximab and 0.4 ± 7.4 m for placebo (P = 0.03). Rituximab treatment appeared to be safe and well tolerated. Low levels of RF (rheumatoid factor), IL-12, and IL-17 were sensitive and specific as favorable predictors of a rituximab response as measured by an improved 6MWD (receiver operating characteristic area under the curve, 0.88-0.95). Conclusions: B-cell depletion therapy is a potentially effective and safe adjuvant treatment for SSc-PAH. Future studies in these patients can confirm whether the identified biomarkers predict rituximab responsiveness. Clinical trial registered with www.clinicaltrails.gov (NCT01086540).

Let's Talk About BiTEs and Other Drugs in the Real-Life Setting for B-Cell Acute Lymphoblastic Leukemia

Background: Therapy for acute lymphoblastic leukemia (ALL) are currently initially efficient, but even if a high percentage of patients have an initial complete remission (CR), most of them relapse. Recent data shows that immunotherapy with either bispecific T-cell engagers (BiTEs) of chimeric antigen receptor (CAR) T cells can eliminate residual chemotherapy-resistant B-ALL cells.

Objective: The objective of the manuscript is to present improvements in the clinical outcome for chemotherapy-resistant ALL in the real-life setting, by describing Romania's experience with bispecific antibodies for B-cell ALL.

Methods: We present the role of novel therapies for relapsed B-cell ALL, including the drugs under investigation in phase I-III clinical trials, as a potential bridge to transplant. Blinatumomab is presented in a critical review, presenting both the advantages of this drug, as well as its limitations.

Results: Bispecific antibodies are discussed, describing the clinical trials that resulted in its approval by the FDA and EMA. The real-life setting for relapsed B-cell ALL is described and we present the patients treated with blinatumomab in Romania.

Conclusion: In the current manuscript, we present blinatumomab as a therapeutic alternative in the bridge-to-transplant setting for refractory or relapsed ALL, to gain a better understanding of the available therapies and evidence-based data for these patients in 2019.

Treatment efficacy for adult persistent immune thrombocytopenia: a systematic review and network meta-analysis

Persistent immune thrombocytopenia (ITP) patients require second-line treatments, for which information on clinical outcomes are lacking. A systematic review and network meta-analysis (NMA) were conducted. Only randomised controlled trials (RCT) of second-line drugs in adult persistent ITP patients with platelet response, platelet count, any bleeding or serious adverse events (SAE) outcome were eligible. Twelve RCTs (n = 1313) were included in NMA. For platelet response outcome, eltrombopag and romiplostin were the best relative to placebo; the former had a non-significant advantage [risk ratio (RR) = 1·10 (95% confidence interval: 0·46, 2·67)]. Both treatments were superior to rituximab and recombinant human thrombopoietin (rhTPO)+rituximab, with corresponding RRs of 4·56 (1·89, 10·96) and 4·18 (1·21, 14·49) for eltrombopag; 4·13 (1·56, 10·94) and 3·79 (1·02, 14·09) for romiplostim. For platelet count, romiplostim ranked highest, followed by eltrombopag, rhTPO+rituximab, and rituximab. For bleeding, rituximab had lowest risk, followed by eltrombopag and romiplostim. For SAEs, rhTPO+rituximab had highest risk, followed by rituximab, eltrombopag and romiplostim. From clustered ranking, romiplostim had the best balance between short-term efficacy and SAEs, followed by eltrombopag. In conclusion, romiplostim and eltrombopag may yield high efficacy and safety. Rituximab may not be beneficial due to lower efficacy and higher complications compared with the thrombopoietin receptor agonists. RCTs with long-term clinical outcomes are required.

[The value of platelet count in predicting the efficacy of rituximab treatment in adult patients with chronic primary immune thrombocytopenia]

Objective: To investigate the value of platelet count in predicting the efficacy of rituximab treatment in chronic primary immune thrombocytopenia (ITP). Methods: A retrospective study was conducted in 103 chronic ITP patients hospitalized in our medical center between January 2011 and December 2014. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) of platelet count in different time points were analyzed for the predictor of treatment response. Optimal cutoff values were established using ROC analysis. Results: A total of 103 patients were included in the study. There were 46 males and 57 females, with a median age of 30 (18-67) years. At day 1, 3 and 7 after the first dose of rituximab, there was no significant difference in platelet counts between the success group (PLT≥50×10(9)/L after treatment) and the failure group (PLT≤50×10(9)/L after treatment) (P>0.05). At day 14 after rituximab treatment (PTD 14), platelet counts became significantly different in the success and failure groups[41(8-384)×10(9)/L vs 23(0-106)×10(9)/L, P=0.003], and remained different thereafter, with increasing significance in the subsequent follow-ups. Patients were divided further using an optimal cut-off platelet count of 50×10(9)/L on PTD 14, PTD 30, and PTD 60, and PPV and NPV values were calculated for predicting eventual success and failure. Conclusion: Response can be predicted by obtaining platelet counts at 14, 30 and 60 days after rituximab treatment. The study proposed a protocol that guides patient monitoring and management planning.

Travel and biologic therapy: travel-related infection risk, vaccine response and recommendations

BACKGROUND

Biologic therapy has revolutionized the management of refractory chronic autoimmune and auto-inflammatory disease, as well as several malignancies, providing rapid symptomatic relief and/or disease remission. Patients receiving biologic therapies have an improved quality of life, facilitating travel to exotic destinations and potentially placing them at risk of a range of infections. For each biologic agent, we review associated travel-related infection risk and expected travel vaccine response and effectiveness.

METHODS

A PUBMED search [vaccination OR vaccine] AND/OR ['specific vaccine'] AND/OR [immunology OR immune response OR response] AND [biologic OR biological OR biologic agent] was performed. A review of the literature was performed in order to develop recommendations on vaccination for patients in receipt of biologic therapy travelling to high-risk travel destinations.

RESULTS

There is a paucity of literature in this area, however, it is apparent that travel-related infection risk is increased in patients on biologic therapy and when illness occurs they are at a higher risk of complication and hospitalization. Patients in receipt of biologic agents are deemed as having a high level of immunosuppression-live vaccines, including the yellow fever vaccine, are contraindicated. Inactivated vaccines are considered safe; however, vaccine response can be attenuated by the patient's biologic therapy, thereby resulting in reduced vaccine effectiveness and protection.

CONCLUSIONS

Best practice requires a collaborative approach between the patient's primary healthcare physician, relevant specialist and travel medicine expert, who should all be familiar with the immunosuppressive and immunomodulatory effects resulting from the biologic therapies. Timing of vaccines should be carefully planned, and if possible, vaccination provided well before established immunosuppression.

The Effect of Histological CD20-Positive B Cell Infiltration in Acute Cellular Rejection on Kidney Transplant Allograft Survival

Background. It is controversial whether lymphocyte infiltration exhibited in biopsy specimens is associated with transplant outcomes. This study focused on the effect of CD20-positive B cell infiltration in biopsy specimens from allografts with acute cellular rejection (ACR) in a Chinese population. Methods. Altogether, 216 patients transplanted from Sep. 2001 to Dec. 2014 with biopsy-proved ACR (Banff I or Banff II) were included in the analysis. Biopsies were immunostained for CD20 and C4d. Baseline information, serum creatinine and GFR before and after treatment, steroid resistance, response to treatment, graft loss, and survival were analyzed. Results. Eighty-three patients were classified into CD20-negative group, and 133 patients were classified into CD20-positive group. Significantly more CD20-negative patients (49/83, 59.0%) received steroid plus antibody therapy compared with the CD20-positive group (52/133, 39.1%) (P = 0.004). The response to treatment for ACR did not differ between these two groups. The CD20-positive group had less graft loss (18.8% versus 32.5%, P = 0.022) and a better graft survival rate. Further exploration of the infiltration degree suggested that it tended to be positively related to graft survival, but this did not reach statistical significance. Conclusion. CD20-positive B cell infiltration in renal allograft biopsies with ACR is associated with less steroid resistance and better graft survival. The presence of CD20-positive B cells is protective for renal allografts.

Low Dose Rituximab in Chronic ITP: Still an Option in Resource Limited Settings

The etiology of ITP remains unknown but its pathogenesis consists of loss of tolerance to platelet antigens. There is a complex dysregulation of the immune system involving both the B cells and the T cells. Splenectomy is the standard second line option in steroid refractory chronic ITP patients. However, costs of surgery and reluctance for surgery in severely thrombocytopenic patients on part of surgeons are major obstacles in resource limited settings. Rituximab has been used in both the standard doses of 375 mg/m² and low doses of 100 mg/m² with similar results. We studied the utility of low dose Rituximab (@100 mg/m² weekly × 4 doses) in resource limited settings. Overall response, complete response (CR) and partial response (PR) rates were 47.6% (10/21), 33.3% (7/21) and 14.3% (3/21) respectively. Median time to response in patients achieving CR was 75 days (range 45-185 days) while in patients achieving PR it was 105 days (range 45-165 days). However, there was no significant difference between males and females achieving CR or PR. We also observed that patients who had earlier responded to any form of treatment were more likely to respond to Rituximab treatment. The cumulative relapse free survival (RFS) at 13 months was 78%. By giving lower dose, six times less than conventional dosing dose, we have been able to demonstrate cost effectiveness in our study population. We were able to administer all the doses in day care without any major adverse events leading to further cost savings on in-patient care.

Treatment Algorithms in Systemic Lupus Erythematosus

OBJECTIVE

To establish agreement on systemic lupus erythematosus (SLE) treatment.

METHODS

SLE experts (n = 69) were e-mailed scenarios and indicated preferred treatments. Algorithms were constructed and agreement determined (≥50% respondents indicating ≥70% agreement).

RESULTS

Initially, 54% (n = 37) responded suggesting treatment for scenarios; 13 experts rated agreement with scenarios. Fourteen of 16 scenarios had agreement as follows: discoid lupus: first-line therapy was topical agents and hydroxychloroquine and/or glucocorticoids then azathioprine and subsequently mycophenolate (mofetil); uncomplicated cutaneous vasculitis: initial treatment was glucocorticoids ± hydroxychloroquine ± methotrexate, followed by azathioprine or mycophenolate and then cyclophosphamide; arthritis: initial therapy was hydroxychloroquine and/or glucocorticoids, then methotrexate and subsequently rituximab; pericarditis: first-line therapy was nonsteroidal antiinflammatory drugs, then glucocorticoids with/without hydroxychloroquine, then azathioprine, mycophenolate, or methotrexate and finally belimumab or rituximab, and/or a pericardial window; interstitial lung disease/alveolitis: induction was glucocorticoids and mycophenolate or cyclophosphamide, then rituximab or intravenous gamma globulin (IVIG), and maintenance followed with azathioprine or mycophenolate; pulmonary hypertension: glucocorticoids and mycophenolate or cyclophosphamide and an endothelin receptor antagonist were initial therapies, subsequent treatments were phosphodiesterase-5 inhibitors and then prostanoids and rituximab; antiphospholipid antibody syndrome: standard anticoagulation with/without hydroxychloroquine, then a thrombin inhibitor for venous thrombosis, versus adding aspirin or platelet inhibition drugs for arterial events; mononeuritis multiplex and central nervous system vasculitis: first-line therapy was glucocorticoids and cyclophosphamide followed by maintenance with azathioprine or mycophenolate, and then rituximab, IVIG, or plasmapheresis; and serious lupus nephritis: first-line therapy was glucocorticoids and mycophenolate, then cyclophosphamide then rituximab.

CONCLUSION

We established variable agreement on treatment approaches. For some treatment decisions there was good agreement between experts even if no randomized controlled trial data were available.

Have splenectomy rate and main outcomes of ITP changed after the introduction of new treatments? A monocentric study in the outpatient setting during 35 years

In the last years, rituximab (RTX) and agonists of the thrombopoietin receptor (TPO-R) eltrombopag and romiplostim have provided new treatment options in persistent and chronic immune thrombocytopenia (ITP). Here, we analyzed the changes in therapeutic choices over time and their impact on clinical outcomes in a cohort of 557 ITP outpatients followed at the "L. and A. Seràgnoli" Institute of Hematology, Bologna, Italy, from 1980 to 2015. Overall 397 patients (71%) required front-line corticosteroids, mainly prednisone. Over the decades, splenectomy was delayed from second to third-line, but was steadily used in around 15-25% of patients refractory or relapsing after first-line treatment. Consensually, RTX and TPO-R agonists emerged as second and third-line therapy of choice, respectively. Splenectomy was associated with the best response rates and the lower incidences of relapse, while the relapse rate after RTX was comparable to that observed with corticosteroids and other immunosuppressive agents. The introduction of TPO-R agonists gave an alternative to the administration of immunosuppressive drugs and probably contributed to moderate the incidence of infectious complications that remained stable over the decades, despite an increasing use of RTX from the 2000s onwards. Overall responses were similar over time, with over 97% achieving a response in all time-periods. However, the cumulative risk of bleeding significantly decreased [14.3% (1980-89) vs. 7% (1990-99) vs. 5.6% (2000-09) vs. 0.2% (2010-15)] (P < 0.001), mainly thanks to the optimization of front-line corticosteroids therapy and to the wider availability of second and third-line therapies.

Rituximab Therapy in Adults with Refractory Symptomatic Immune Thrombocytopenia: Long-Term Follow-Up of 15 Cases

Objective:

This paper prospectively evaluates the long-term follow-up [mean ± standard deviation (SD) duration: 89.7±19.4 months] data of 15 patients (13 females and 2 males) with refractory symptomatic immune thrombocytopenia (ITP) treated with rituximab.

Materials and Methods:

Rituximab was administered at 375 mg/m2 weekly for a total of 4 doses. Complete response (CR) was defined as a platelet count of ≥100,000/mm³ and partial response (PR) as a platelet count of ≥30,000/mm³ but less than 100,000/mm³. Early response (ER) and late response (LR) were defined as response within 42 days and after 42 days of initiation of rituximab therapy, respectively. Sustained response (SR) was defined as response lasting for at least 6 months.

Results:

Mean age (±SD) at the start of rituximab was 46.6±11.3 years. Mean platelet count (±SD) prior to rituximab treatment was 17,400±8878/mm³. The mean time (±SD) between rituximab therapy and response to rituximab in early responders and late responders was 1.8±1.3 weeks and 10±2.8 weeks, respectively. Mean durations (±SD) of ER and LR were 51±47.2 months and 6±4.2 months, respectively. Seven of the 15 patients (46.7%) showed an initial response to rituximab (5 ER and 2 LR). The rate of SR over 6 months was 26.7% (4/15). Among the responders to rituximab, 3 (3/7, 42.9%) maintained their response 1 year after rituximab treatment and 2 (2/7, 28.6%) had ongoing response 5 years after initiation of rituximab. Two of the 7 patients (28.6%) still maintained their response 98 months after initiation of rituximab. All 5 initial responders with subsequent relapse achieved response from subsequent treatment modalities (3 CR, 2 PR).

Conclusion:

Our data confirm, over a long period of observation, that rituximab is safe and effective in the management of patients with chronic refractory primary ITP.

A molecular perspective on rituximab: A monoclonal antibody for B cell non Hodgkin lymphoma and other affections

Rituximab (a chimeric anti-CD20 monoclonal antibody) is the first Food and Drug Administration approved anti-tumor antibody. Immunotherapy by rituximab, especially in combination-therapy, is a mainstay for a vast variety of B-cell malignancies therapy. Its therapeutic value is unquestionable, yet the mechanisms of action responsible for anti-tumor activity of rituximab and rituximab resistance mechanisms are not completely understood. Investigation of the mechanisms of action that contribute to the rituximab activity have eventually directed to a suite of novel combinations and novel treatment schedules, and also have resulted new generations of antibodies with more desired effects. Although, further investigations are needed to define the mechanisms of rituximab resistance and prominent effector activity of the altered next generation anti-CD20 to improve their efficacies and develop new anti-CD20 monoclonal antibodies in NHL treatment. This article focuses on the properties of CD20 which led scientists to select it as an effective therapeutic target and the molecular details of mechanisms of rituximab action and resistance. We also discuss about the impact of rituximab in monotherapy and in combination with chemotherapy regimens. Finally, we comparatively summarize the next generations of anti CD20 monoclonal antibodies to highlight their advantages relative to their ancestor: Rituximab.

Rituximab leads to long remissions in patients with chronic immune thrombocytopenia

OBJECTIVES

To assess the response rate and duration of response in patients with chronic immune thrombocytopenia (ITP) receiving rituximab.

METHODS

We retrospectively analyzed 32 consecutive patients with chronic ITP who were treated in two tertiary centers in Oman. Response assessment was based on the American Society of Hematology criteria.

RESULTS

Nineteen patients (59%) had an initial response. However, six of the 19 patients lost their response leaving 13 patients with long-lasting remissions. The median age at diagnosis was 25 years (range 14-58). The median time from diagnosis to rituximab therapy was 21 months. The median follow-up after starting rituximab was 26 months. The overall cumulative response rate was 59% (complete response 44%, partial response 15%) and the median time to respond was 30 days with a response rate of 44% at four weeks. In all responders, the cumulative rate of loss of response was 32% with a median time to lose response of 54 months.

CONCLUSIONS

The use of rituximab in ITP achieves high response rate and long remission duration. Our study was limited by the small sample size and further larger prospective studies are recommended.

A multicenter randomized open-label study of rituximab plus rhTPO vs rituximab in corticosteroid-resistant or relapsed ITP

This study aimed to compare the efficacy and safety of rituximab (RTX) plus recombinant human thrombopoietin (rhTPO) with RTX alone in patients with immune thrombocytopenia (ITP) who had failed to respond to corticosteroids or relapsed. Recruited patients were randomized at a ratio of 2:1 into 2 groups: the combination group (RTX + rhTPO, n = 77) and the monotherapy group (RTX, n = 38). Overall response was achieved in 79.2% of patients in the combination group vs 71.1% in the monotherapy group (P = .36), and the complete response (CR) rate was 45.4% in the combination group compared with 23.7% in the monotherapy group (P = .026). The combination group had significantly shorter time to response (TTR; median and range, 7 and 4-28 days) compared with the monotherapy group (28 and 4-90 days) (P < .01). There was no difference between these 2 groups in terms of the long-term response (P = .12). Our findings demonstrated that the combination of RTX and rhTPO significantly increased the CR rate and shortened TTR compared with RTX monotherapy in the treatment of corticosteroid-resistant or relapsed ITP but failed to show a beneficial effect on the long-lasting response. This study is registered at www.clinicaltrials.gov as #NCT01525836.

Idiopathic thrombocytopenic purpura

Idiopathic thrombocytopenic purpura (ITP) is defined as a hematologic disorder, characterized by isolated thrombocytopenia without a clinically apparent cause. The major causes of accelerated platelet consumption include immune thrombocytopenia, decreased bone marrow production, and increased splenic sequestration. The clinical presentation may be acute with severe bleeding, or insidious with slow development with mild or no symptoms. The initial laboratory tests useful at the first visit to predict future diagnosis were erythrocyte count, leukocyte count, anti-glycoprotein IIb/IIIa antibodies, reticulated platelets, plasma thrombopoietin level. Treatment should be restricted to those patients with moderate or severe thrombocytopenia who are bleeding or at risk of bleeding. We present a case report on ITP with clinical presentation, diagnosis and management.

Profound symptomatic hypogammaglobulinemia: a rare late complication after rituximab treatment for immune thrombocytopenia. Report of 3 cases and systematic review of the literature

INTRODUCTION

B-cell depletion with rituximab (RTX) is widely used to treat autoimmune diseases, especially as second-line therapy for immune thrombocytopenia (ITP). The incidence of RTX-induced hypogammaglobulinemia is unknown because of heterogeneous follow-up and confounding factors such as concomitant immunosuppressive treatments in most patients. We describe 3 cases and attempted to determine the incidence of RTX-induced hypogammaglobulinemia by a systematic review of the literature.

METHODS

We retrospectively analyzed 189 ITP patients receiving RTX in 3 referral centers in France and conducted a systematic review of 32 studies (results published 2001-2014) reporting the use of RTX for ITP, particularly searching for symptomatic secondary hypogammaglobulinemia. We also searched for case reports of hypogammaglobulinemia after RTX initiation for ITP.

RESULTS

Of the 189 patients, 3 showed symptomatic hypogammaglobulinemia more than 2years after RTX infusion (initial immunoglobulin level was normal). All 3 presented recurrent severe infections. In 2, the outcome suggested common variable immunodeficiency. In patient 3, the peripheral blood lacked CD19(+)CD20(+) B cells and the bone-marrow B-cell precursor level was impaired. Among 1245 ITP patients in the literature who received RTX for ITP, gammaglobulin level was monitored before and after RTX initiation for 351 (28%). For 192 (55%), dosages were available and we identified 21 patients with secondary hypogammaglobulinemia, usually not symptomatic, 14 of whom had received concomitant dexamethasone. Finally, we found 4 case reports of ITP and symptomatic hypogammaglobulinemia possibly related to RTX according to the authors.

CONCLUSIONS

This large analysis led us to recommend monitoring serum immunoglobulin level before and repeatedly after RTX initiation for ITP. Physicians should be aware of hypogammaglobulinemia as a rare but severe complication of RTX.

Targeted biopharmaceuticals for cancer treatment

Cancer is a complex invasive genetic disease that causes significant mortality rate worldwide. Protein-based biopharmaceuticals have significantly extended the lives of millions of cancer patients. This article reviews the biological function and application of targeted anticancer biopharmaceuticals. We first discuss the specific antigens and core pathways that are used in the development of targeted cancer therapy. The innovative monoclonal antibodies, non-antibody proteins, and small molecules targeting these antigens or pathways are then reviewed. Finally, the current challenges in anticancer biopharmaceuticals development and the potential solutions to address these challenges are discussed.

Drug-induced thrombocytopenia secondary to natalizumab treatment

A 52-year-old woman with a 10-year history of relapsing-remitting multiple sclerosis (RRMS) was started on natalizumab after she developed side effects for interferon β-1a and glatiramer acetate. The patient presented with acute severe infusion reaction after the third treatment with natalizumab, developing whole-body purpura. Laboratory testing revealed progressive worsening thrombocytopenia up to 3 weeks following natalizumab discontinuation. Platelet antibodies to platelet-specific antigen as well as antibodies against natalizumab were positive. Bone marrow biopsy was negative. The patient was diagnosed with drug-induced immune thrombocytopenia (DITP) as a rare case of natalizumab side effect which was treated with intravenous methylprednisolone followed by rituximab with successful resolution of thrombocytopenia. The patient had a stable course of RRMS with no relapses and no brain MRI changes at 2 years after initiation of rituximab.

[Efficacy and safety of rituximab in the treatment of primary antiphospholipid syndrome: analysis of 24 cases from the bibliography review]

BACKGROUND AND OBJECTIVE

Antiphospholipid syndrome (APS) is characterized by the presence of antiphospholipid antibodies (aPL) and thrombotic and/or obstetric manifestations. Patients without another associated autoimmune disease are considered to have primary APS. Some patients develop thrombosis recurrence despite anticoagulant treatment and some clinical features do not respond to standard therapy. Rituximab may be an alternative in these cases. We review the published scientific evidence on the use of rituximab in the treatment of primary APS.

PATIENTS AND METHODS

Description of a case and review of the literature with descriptive analysis of the demographic, clinical, and immunologic features, treatment and outcome of patients.

RESULTS

We identified 24 patients (15 women [62.5%]), with a mean age of 37.0 ± 13.4 years. The reasons for the use of rituximab were thrombocytopenia (41.7%), skin involvement (33.3%), neurologic and heart valve involvement (12.5%), hemolytic anemia (8.3%) and pulmonary and renal involvement (4.2%). Lupus anticoagulant was present in 72.7% of the cases, the IgG and IgM isotypes of anticardiolipin antibodies in 75 and 50%, respectively, and the anti-β2GPI (IgG e IgM) antibodies in 80% of patients. Thirteen (54.1%) patients received 2 doses of 1,000 mg of rituximab fortnightly, 10 (41.7%) 4 doses of 375 mg/m(2) weekly and one (4.2%) 8 doses of 375 mg/m(2) weekly. Eleven (45.8%) patients presented a complete clinical response, 7 (29.2%) a partial response and 6 (25%) did not respond to rituximab. Four patients with clinical improvement presented with aPL titer decrease and in one patient, aPL levels did not change. In one patient without clinical response, aPL remained positive. A clinical-immunologic dissociation existed in 2 additional cases.

CONCLUSIONS

The results obtained suggest a possible potential benefit of rituximab in the treatment of some clinical manifestations of primary APS such as thrombocytopenia, skin and heart valve involvement.

The expanding role of therapeutic antibodies

Therapeutic antibodies have been used since the end of nineteenth century, but their use is progressively increased and recently, with the availability of monoclonal antibodies, they are successfully employed in a large disease spectrum, which transversally covers different fields of medicine. Hyperimmune polyclonal immune globulin has been used against infectious diseases, in a period in which anti-microbial drugs were not yet available, and it still maintains a relevant place in prophylaxis/therapy. Although immune globulin should be considered life-saving as replacement therapy in humoral immunodeficiencies, its place in the immune-modulating treatment is not usually first-choice, but it should be considered as support to standard approved treatments. Despite therapeutic monoclonal antibodies have been lastly introduced in therapy, their extreme potentiality is reflected by the large number of approved molecules, addressed toward different immunological targets and able to heavily influence the prognosis and quality of life of a wide range of different diseases.

Rituximab

Rituximab (Rituxan^®, MabThera^®, and Genentech/Roche) is a chimeric murine/human monoclonal IgG1k antibody directed against the CD20 antigen located at the surface of normal and malignant B lymphocytes.

Rituximab in previously treated primary immune thrombocytopenia patients: evaluation of short- and long-term efficacy and safety

The anti-CD20 chimeric monoclonal antibody rituximab has been effectively used in the treatment of patients with primary immune thrombocytopenia (pITP). We retrospectively evaluated 19 patients affected by pITP resistant to 2 or more lines of therapy who were treated with rituximab. Nine of the 19 patients showed an initial response (47.4%). The sustained response rate was 31.6% (6/19). The median follow-up of the patients was 53.2 months (range 9.2-92.9). Disease-free survival at 48 months was 62.2%. Following rituximab treatment, a proportion of patients (42%) recovered a normal B lymphocyte number. During the follow-up, no opportunistic or severe infectious complications were observed. These data confirm, over a long period of observation, the efficacy and safety of rituximab treatment in the management of patients with resistant pITP.

Low-dose anti-CD20 veltuzumab given intravenously or subcutaneously is active in relapsed immune thrombocytopenia: a phase I study

Low doses of the humanized anti-CD20 monoclonal antibody, veltuzumab, were evaluated in 41 patients with immune thrombocytopenia (ITP), including 9 with ITP ≤1 year duration previously treated with steroids and/or immunoglobulins, and 32 with ITP >1 year and additional prior therapies. They received two doses of 80-320 mg veltuzumab 2 weeks apart, initially by intravenous (IV) infusion (N = 7), or later by subcutaneous (SC) injections (N = 34), with only one Grade 3 infusion reaction and no other safety issues. Thirty-eight response-assessable patients had 21 (55%) objective responses (platelet count ≥30 × 10(9) /l and ≥2 × baseline), including 11 (29%) complete responses (CRs) (platelet count ≥100 × 10(9) /l). Responses (including CRs) occurred with both IV and SC administration, at all veltuzumab dose levels, and regardless of ITP duration. Responders with ITP ≤1 year had a longer median time to relapse (14·4 months) than those with ITP >1 year (5·8 months). Three patients have maintained a response for up to 4·3 years. SC injections resulted in delayed and lower peak serum levels of veltuzumab, but B-cell depletion occurred after first administration even at the lowest doses. Eight patients, including 6 responders, developed anti-veltuzumab antibodies following treatment (human anti-veltuzumab antibody, 19·5%). Low-dose SC veltuzumab appears convenient, well-tolerated, and with promising clinical activity in relapsed ITP.(Clinicaltrials.gov identifier: NCT00547066.).

Detection of the FCGR3a polymorphism using a real-time polymerase chain reaction assay

The fragment crystallizable (Fc) region of the immunoglobulin G, low affinity III A receptor (FCGR3a, also known as CD16) belongs to the Fc gamma receptor family (FCGR), which plays an important role in immunoinflammatory processes. It is a low affinity, transmembrane receptor that is mainly expressed in monocytes, natural killer cells, and macrophages. It has been implicated in various inflammatory conditions, and recently a polymorphism (rs396991) in this gene has been shown to influence response to rituximab (anti-CD20) therapy in various disorders. We evaluated two molecular methods to genotype this polymorphism. Archived, formalin-fixed, paraffin-embedded samples from 26 biopsies of diffuse large B-cell lymphoma were retrieved and DNA was extracted. The samples were tested for the FCGR3a polymorphism using real-time polymerase chain reaction (PCR) followed by melt curve analysis or by a standard TaqMan allelic discrimination assay using the ABI 7500 FAST real-time PCR instrument. With the TaqMan allelic discrimination assay, we found that 16 cases were the wild type genotype, homozygous phenylalanine (F/F), for the FCGR3a receptor, whereas two cases had the homozygous valine (V/V) polymorphism and eight cases were heterozygous with a V/F genotype. Results with the real-time PCR followed by melt curve analysis were similar for 25 cases; however, four samples did not have sufficient DNA for the melt curve analysis method, and the result from one sample was discordant. The new TaqMan assay offers several advantages over previously published assays, such as faster turnaround time and ease of interpretation. These performance characteristics make it highly suitable for use in a clinical laboratory.

Clinical review: Serious adverse events associated with the use of rituximab - a critical care perspective

The advent of biologic agents has provided a more specific and targeted approach to the treatment of various hematological malignancies and other autoimmune disorders. Such biologic agents have been relatively well tolerated with fewer adverse events reported as compared with many other chemotherapeutic agents. Rituximab is a monoclonal antibody to the B-cell marker CD20 and is a common biologic agent widely used for the treatment of B-cell lymphoma, lymphoproliferative disorders, and inflammatory conditions that are refractory to conventional treatment, including rheumatoid arthritis and some vasculitides. However, through randomized controlled trials and post-marketing surveillance, an increasing number of serious adverse events are being associated with the use of rituximab, often leading to or complicating an intensive care unit admission. The purpose of this review is to focus on the severe complications that are associated with the use of rituximab and that require critical care. Management and prevention strategies for the most common complications along with some examples of its uses within the critical care setting are also discussed.

Successful treatment of refractory idiopathic thrombocytopenic purpura and neutropenia with the monoclonal antibody, rituximab

We describe a 22-year-old male with idiopathic autoimmune thrombocytopenia whose diagnosis was made at age of eight. He underwent splenectomy at age ten and ITP recurred at age 21 with episodes of infection and severe neutropenia (absolute count around 170/μl). He showed no response to immunoglobulin, corticosteroids, danazol, cyclosporine and azathioprine. Anti-CD20 antibody was administered at a dose of 375 mg/m(2) once a week for 2 weeks. After the second infusion of rituximab, the platelet count increased from 4,000 to 516,000/mm(3) and neutrophils count raised from 180 to 545/mm(3). The response improvement persisted during follow up for 9 months (neutrophil count 4,390/mm(3)). This observation indicates that B-cells may play a central role in the pathogenesis of ITN. Anti-CD20 antibody therapy may be an efficient treatment for the patients with chronic or recurrent ITN.

Outcomes 5 years after response to rituximab therapy in children and adults with immune thrombocytopenia

Treatments for immune thrombocytopenic purpura (ITP) providing durable platelet responses without continued dosing are limited. Whereas complete responses (CRs) to B-cell depletion in ITP usually last for 1 year in adults, partial responses (PRs) are less durable. Comparable data do not exist for children and 5-year outcomes are unavailable. Patients with ITP treated with rituximab who achieved CRs and PRs (platelets > 150 × 10(9)/L or 50-150 × 10(9)/L, respectively) were selected to be assessed for duration of their response; 72 adults whose response lasted at least 1 year and 66 children with response of any duration were included. Patients had baseline platelet counts < 30 × 10(9)/L; 95% had ITP of > 6 months in duration. Adults and children each had initial overall response rates of 57% and similar 5-year estimates of persisting response (21% and 26%, respectively). Children did not relapse after 2 years from initial treatment whereas adults did. Initial CR and prolonged B-cell depletion predicted sustained responses whereas prior splenectomy, age, sex, and duration of ITP did not. No novel or substantial long-term clinical toxicity was observed. In summary, 21% to 26% of adults and children with chronic ITP treated with standard-dose rituximab maintained a treatment-free response for at least 5 years without major toxicity. These results can inform clinical decision-making.

[Pathogenic basis of B cell targeted therapy in systemic lupus erythematosus (SLE)]

Recent success of B-cell targeted therapies in rheumatoid arthritis suggests their potential efficacy for other auntoantibody-mediated autoimmune diseases. Currently, multiple agents directed toward different B-cell specific targets are under development. Although the best strategy is yet to be defined, multiple functional inhibitors or cytolitic agents such as anti-CD20 or anti-CD19 are available. According to studies in RA, the most likely mechanism of action of rituximab (anti-CD20) consists of a secondary reduction in local (synovial) or systemic autoantibody producing short-lived plasma cells. According to this data, it is expected that these therapies will be efficacious in SLE, were B-cell enhanced function and autoantibodies play relevant pathogenetic roles. Clinical trials confirm B-cell effects, delayed activity on autoantibody synthesis, and most importantly, the feasibility of these therapies to treat SLE. However, there are no sufficient data confirming their therapeutic value when added to convencional therapy. Although multiple open trials suggest that rituximab might be useful for refractory manifestations of SLE, more controlled trials are needed in order to establish the indications and strategies of its use in SLE.

Rituximab therapy for autoimmune haematological diseases

Autoimmune haematological diseases are characterized by the production of antibodies against blood proteins or cells, and comprise primary immune thrombocytopenia, autoimmune haemolytic anaemia, acquired haemophilia, and thrombotic thrombocytopenic purpura. Current treatments for these disorders include corticosteroids, cytotoxic drugs and splenectomy, which may be associated with significant systemic toxicity and/or morbility. B cells play a key role in both the development and perpetuation of autoimmunity, since they produce autoantibodies but also function as antigen-presenting cells, and release immunomodulatory cytokines. Rituximab, an anti-CD20 monoclonal antibody that specifically depletes B cells, may be an effective treatment strategy for patients with autoimmune disorders. This article reviews data of the literature, showing that patients with autoimmune haematological diseases can respond to rituximab irrespective of age and number or type of prior treatments. These data suggest that rituximab provides an effective and well-tolerated treatment option for these conditions.

Anti-CD20 monoclonal antibodies and their use in adult autoimmune hematological disorders

Autoimmune hematological disorders encompass a broad group of hematological conditions characterized by the loss of self-tolerance to a variety of antigens. Despite good response to first-line therapy in the majority of patients, relapses are common, necessitating new and safe therapeutic options. The anti-CD20 monoclonal antibody rituximab has led to substantial improvement in the treatment of malignant and immune-mediated disorders involving B cells. Although experience with rituximab in immune-mediated hematological disorders is rarely supported by randomized trials, there is now substantial experience with rituximab suggesting that anti-CD20 therapy is an effective and well-tolerated alternative to immunosuppressive therapy in these disorders. However, caution is needed based on recent reports describing-sometimes severe-rituximab-related complications.