Late-onset neutropenia following rituximab therapy: incidence, clinical features and possible mechanisms

Non-late-onset neutropaenia following treatment of multiple sclerosis with ocrelizumab

Late-onset neutropaenia is defined as an absolute neutrophil count of <1.5×103cells/μL starting>4 weeks after the last dose of rituximab, in the absence of other identifiable causes. Late-onset neutropaenia is a rare adverse reaction to rituximab (observed in approximately 5% of patients). Rheumatic diseases constitute the main indication for rituximab; in these patients, neutropaenia appears after a mean of>28 days. Ocrelizumab is another monoclonal antibody that binds to CD20 (a glycosylated phosphoprotein mainly expressed on the membranes of B-lymphocytes); in January 2018, it was approved for the treatment of relapsing-remitting and primary progressive multiple sclerosis. We present a case of neutropaenia following intravenous infusion of ocrelizumab in a patient with primary progressive multiple sclerosis who presented with neutropaenic fever, herpetic stomatitis, and ecthyma gangrenosum only 20 days after infusion.

Hypogammaglobulinemia, late-onset neutropenia, and infections following rituximab

Rituximab is a chimeric anti-CD20 monoclonal antibody that targets CD20-expressing B lymphocytes, has a well-defined efficacy and safety profile, and is broadly used to treat a wide array of diseases. In this review, we cover the mechanism of action of rituximab and focus on hypogammaglobulinemia and late-onset neutropenia-2 immune effects secondary to rituximab-and subsequent infection. We review risk factors and highlight key considerations for immunologic monitoring and clinical management of rituximab-induced secondary immune deficiencies. In patients treated with rituximab, monitoring for hypogammaglobulinemia and infections may help to identify the subset of patients at high risk for developing poor B cell reconstitution, subsequent infections, and adverse complications. These patients may benefit from early interventions such as vaccination, antibacterial prophylaxis, and immunoglobulin replacement therapy. Systematic evaluation of immunoglobulin levels and peripheral B cell counts by flow cytometry, both at baseline and periodically after therapy, is recommended for monitoring. In addition, in those patients with prolonged hypogammaglobulinemia and increased infections after rituximab use, immunologic evaluation for inborn errors of immunity may be warranted to further risk stratification, increase monitoring, and assist in therapeutic decision-making. As the immunologic effects of rituximab are further elucidated, personalized approaches to minimize the risk of adverse reactions while maximizing benefit will allow for improved care of patients with decreased morbidity and mortality.

Predictors of hospitalization due to infection in rituximab-treated MS patients

BACKGROUND

Rituximab is extensively used off-label to treat multiple sclerosis (MS), and long-term vigilance for adverse events is needed. This study was conducted to determine frequencies and predictors of hematological adverse events, including hypogammaglobulinemia, severe lymphopenia, neutropenia, and infections leading to hospitalization.

METHODS

This retrospective cohort study included all patients with MS initiating rituximab treatment at Haukeland University Hospital between January 1^st, 2017, and July 1^st, 2021. Patients were followed by clinical monitoring and repeated blood sampling every six months. Clinical outcomes and laboratory results were retrieved from the Norwegian MS Registry and Biobank and the patient administrative system at Haukeland University Hospital.

RESULTS

Five hundred and fifty-six patients were included, 515 with relapsing-remitting MS (RRMS) and 41 with progressive MS. Overall, 33 patients (5.9%) experienced 56 episodes of infections requiring hospital admission. Sixty patients (10.8%) had confirmed hypogammaglobulinemia, 17 (3.1%) had confirmed severe lymphopenia, and 10 (1.8%) had confirmed severe neutropenia. Predictors of infection requiring hospital admission were progressive MS (adjusted OR (aOR): 4.81; 95%CI: 1.25-18.48), duration of treatment with rituximab (aOR: 1.52; 95%CI: 1.11-2.09) and confirmed severe lymphopenia (aOR: 13.58; 95%CI: 3.41-54.06) and neutropenia (aOR: 13.40; 95%CI: 2.93-61.25). Of the hematological abnormalities, only hypogammaglobulinemia was associated with treatment duration (aOR: 1.35; 95%CI: 1.09-1.69).

CONCLUSION

The risk of hospitalization due to infection is associated with time on rituximab treatment, in patients with lympho- or neutropenia, and in patients with primary progressive MS. We observed a time-dependent decline in IgG values, in contrast to neutrophil and lymphocyte count, suggesting a cumulative dose-dependent response. These predictors can assist clinicians in assessing and monitoring MS patients receiving rituximab.

Anti-CD20 therapies in multiple sclerosis: From pathology to the clinic

The immune system plays a significant role in multiple sclerosis. While MS was historically thought to be T cell-mediated, multiple pieces of evidence now support the view that B cells are essential players in multiple sclerosis pathogenic processes. High-efficacy disease-modifying therapies that target the immune system have emerged over the past two decades. Anti-CD20 monoclonal antibodies selectively deplete CD20+ B and CD20+ T cells and efficiently suppress inflammatory disease activity. These monotherapies prevent relapses, reduce new or active magnetic resonance imaging brain lesions, and lessen disability progression in patients with relapsing multiple sclerosis. Rituximab, ocrelizumab, and ofatumumab are currently used in clinical practice, while phase III clinical trials for ublituximab have been recently completed. In this review, we compare the four anti-CD20 antibodies in terms of their mechanisms of action, routes of administration, immunological targets, and pharmacokinetic properties. A deeper understanding of the individual properties of these molecules in relation to their efficacy and safety profiles is critical for their use in clinical practice.

Acquired B-cell deficiency secondary to B-cell-depleting therapies

The advantage of the newer biological therapies is that the immunosuppressive effect is targeted, in contrast, to the standard, traditional immunomodulatory agents, which have a more global effect. However, there are unintended targets and consequences, even to these "precise" therapeutics, leading to acquired or secondary immunodeficiencies. Besides depleting specific cellular immune subsets, these biological agents, which include monoclonal antibodies against biologically relevant molecules, often have broader functional immune consequences, which become apparent over time. This review focuses on acquired B-cell immunodeficiency, secondary to the use of B-cell depleting therapeutic agents. Among the many adverse consequences of B-cell depletion is the risk of hypogammaglobulinemia, failure of B-cell recovery, impaired B-cell differentiation, and risk of infections. Factors, which modulate the outcomes of B-cell depleting therapies, include the intrinsic nature of the underlying disease, the concomitant use of other immunomodulatory agents, and the clinical status of the patient and other co-existing morbidities. This article seeks to explore the mechanism of action of B-cell depleting agents, the clinical utility and adverse effects of these therapies, and the relevance of systematic and serial laboratory immune monitoring in identifying patients at risk for developing immunological complications, and who may benefit from early intervention to mitigate the secondary consequences. Though these biological drugs are gaining widespread use, a harmonized approach to immune evaluation pre-and post-treatment has not yet gained traction across multiple clinical specialties, because of which, the true prevalence of these adverse events cannot be determined in the treated population, and a systematic and evidence-based dosing schedule cannot be developed. The aim of this review is to bring these issues into focus, and initiate a multi-specialty, data-driven approach to immune monitoring.

Late-onset toxicities of monoclonal antibodies in cancer patients

Cancer therapy duration is variable and may take years, adding a new challenge of maintaining the best life quality for cancer survivors. In cancer patients, late-onset toxicities have been reported with monoclonal antibodies and may involve several body organs or systems. They are defined as an autoimmune illnesses that can happen months to years after treatment discontinuation. Late-onset toxicities have become a focus of clinical care and related research. After cancer therapy is completed, the patient should receive longitudinal follow-up to detect these late effects as early as possible. The current review summarizes the recently reported late-onset toxicities of four classes of monoclonal antibodies (anti-CD52, anti-CTLA-4, anti-PD-1 and anti-CD20) with guidance for the diagnostic tools, appropriate management and treatment.

Cytopenia after CAR-T Cell Therapy-A Brief Review of a Complex Problem

Chimeric Antigen Receptor T-cell (CAR-T) immunotherapy has emerged as an efficacious and life extending treatment modality with high response rates and durable remissions in patients with relapsed and refractory non-Hodgkin lymphoma (NHL), follicular lymphoma, and B-cell acute lymphoblastic leukemia (B-ALL) as well as in other diseases. Prolonged or recurrent cytopenias after CAR-T therapy have increasingly been reported at varying rates, and the pathogenesis of this complication is not yet well-understood but is likely contributed to by multiple factors. Current studies reported are primarily retrospective, heterogeneous in terms of CAR-Ts used and diseases treated, non-uniform in definitions of cytopenias and durations for end points, and vary in terms of recommended management. Prospective studies and correlative laboratory studies investigating the pathophysiology of prolonged cytopenias will enhance our understanding of this phenomenon. This review summarizes knowledge of these cytopenias to date.

Case Report: High Doses of Intravenous Immunoglobulins as a Successful Treatment for Late Onset Immune Agranulocytosis After Rituximab Plus Bendamustine

Late onset neutropenia (LON) related to rituximab or rituximab plus chemotherapy is defined as an unexplained absolute neutrophil count of ≤1.5 × 10⁹/L starting at least four weeks after the last rituximab administration. LON is infrequent and its pathophysiology remains unknown. There are no guidelines or consensus strategies for the optimal management of patients developing LON. The majority of the patients recover promptly with no specific treatment and only some cases need to be managed with granulocytic colony stimulating factor (G-CSF), usually with a rapid response. Here, we describe a 69-year-old patient with Waldenström's macroglobulinemia who presented a septic event in the context of severe LON after rituximab plus bendamustine. The diagnosed of agranulocytosis was established by bone marrow examination. Interestingly, anti-neutrophil antibodies bound to the patient's granulocytes were found suggesting an autoimmune mechanism. The patient did not respond to G-CSF but achieved a rapid response after high doses of intravenous immunoglobulins with full white blood cell recovery.

Rituximab for the treatment of multiple sclerosis: a review

In the last decades, evidence suggesting the direct or indirect involvement of B cells on multiple sclerosis (MS) pathogenesis has accumulated. The increased amount of data on the efficacy and safety of B-cell-depleting therapies from several studies has suggested the addition of these drugs as treatment options to the current armamentarium of disease modifying therapies (DMTs) for MS. Particularly, rituximab (RTX), a chimeric monoclonal antibody directed at CD20 positive B lymphocytes resulting in cell-mediated apoptosis, has been demonstrated to reduce inflammatory activity, incidence of relapses and new brain lesions on magnetic resonance imaging (MRI) in patients with relapsing-remitting MS (RRMS). Additional evidence also demonstrated that patients with progressive MS (PMS) may benefit from RTX, which also showed to be well tolerated, with acceptable safety risks and favorable cost-effectiveness profile.Despite these encouraging results, RTX is currently approved for non-Hodgkin's lymphoma, chronic lymphocytic leukemia, several forms of vasculitis and rheumatoid arthritis, while it can only be administered off-label for MS treatment. Between Northern European countries exist different rules for using not licensed drug for treating MS. The Sweden MS register reports a high rate (53.5%) of off-label RTX prescriptions in relation to other annually started DMTs to treat MS patients, while Danish and Norwegian neurologists have to use other anti-CD20 drugs, as ocrelizumab, in most of the cases.In this paper, we review the pharmacokinetics, pharmacodynamics, clinical efficacy, safety profile and cost effectiveness aspects of RTX for the treatment of MS. Particularly, with the approval of new anti-CD20 DMTs, the recent worldwide COVID-19 emergency and the possible increased risk of infection with this class of drugs, this review sheds light on the use of RTX as an alternative treatment option for MS management, while commenting the gaps of knowledge regarding this drug.

An immunogenic first-in-human immune modulatory vaccine with PD-L1 and PD-L2 peptides is feasible and shows early signs of efficacy in follicular lymphoma

Cells in the tumor microenvironment of Follicular lymphoma (FL) express checkpoint molecules such as programmed death ligands 1 and 2 (PD-L1 and PD-L2) and are suppressing anti-tumor immune activity. Stimulation of peripheral blood mononuclear cells (PBMC) with PD-L1 (IO103) or PD-L2 (IO120) peptides can activate specific T cells inducing anti-regulatory functions including cytotoxicity against PD-L1/PD-L2-expressing cells. In this study, we vaccinated eight FL patients with PD-L1 and PD-L2 peptides following treatment with standard chemotherapy. Patients experienced grade 1-2 injection site reaction (5/8) and mild flu-like symptoms (6/8). One patient experienced neutropenia and thrombocytopenia during pseudo-progression. Enzyme-linked immunospot detected vaccine-specific immune responses in PBMC from all patients, predominately toward PD-L1. The circulating immune composition was stable during treatment; however, we observed a reduction regulatory T cells, however, not significant. One patient achieved a complete remission during vaccination and two patients had pseudo-progression followed by long-term disease regression. Further examination of these early signs of clinical efficacy of the dual-epitope vaccine in a larger study is warranted.

Ibrutinib plus rituximab for the treatment of adult patients with Waldenström's macroglobulinemia: a safety evaluation

Introduction: Waldenström's macroglobulinemia (WM), an orphan disease, is a rare low-grade B-cell lymphoplasmacytic lymphoma with unique clinical features and monoclonal IgM production. Rituximab remains to this date the backbone of most commonly used treatment combinations. The FDA/EMA approval of Ibrutinib, the first-in-class BTK inhibitor, either as monotherapy or in combination with rituximab, changed the treatment landscape of the disease.Areas covered: Clinical trial data that demonstrate mode of action, efficacy, and the safety profile of each agent will be covered. A safety analysis of the combination treatment will also be performed to point out its high efficacy and overall favorable toxicity profile. The disadvantages and treatment gaps that still exist in the treatment of WM which relate to the need for long-term ibrutinib administration and the lack of deep remissions and subsequent disease relapse, will also be reviewed.Expert opinion: The ibrutinib-rituximab combination is both effective and safe, in the newly-diagnosed and relapsed-refractory disease setting. The optimal therapeutic approach for WM patients remains however to be established. The question of which combinatory (or synergistic) regimen can allow for a fixed-treatment duration, deep and durable responses with a safe toxicity profile is being addressed in ongoing clinical trials.

The role of BAFF and G-CSF for rituximab-induced late-onset neutropenia (LON) in lymphomas

Mechanisms for late-onset neutropenia (LON) after rituximab treatment are poorly defined both for non-Hodgkin lymphoma (NHL) and for autoimmune disorders. We performed a case–control analysis of a prospective cohort of 169 evaluable consecutive rituximab-treated NHL patients to assess cytokines involved in neutro- and lymphopoiesis (G-CSF, SDF1, BAFF, APRIL) and inflammation (CRP) as possible LON mechanisms. Fifteen patients (9%) developed LON (peripheral blood /PB/ absolute neutrophil counts /ANC/ < 0.5 G/L, all with marked depletion of CD20⁺ B-lymphocytes in bone marrows); they were compared with 20 matched NHL controls without LON. At start of LON, significantly higher PB G-CSF and BAFF levels (P = 0.0004 and 0.006, respectively), as well as CRP rises were noted compared to controls; these G-CSF and BAFF and most CRP values returned to levels of the controls in post-LON samples. G-CSF (but not BAFF) changes correlated to CRP rises (but not to ANC levels). BAFF levels correlated significantly to absolute monocyte counts and PB large granular lymphocyte counts (but not to ANC, C-CSF or CRP values). No changes of SDF1 or APRIL levels were noted. Neither LON cases nor controls displayed anti-neutrophil autoantibodies. Collectively, LON in NHL patients was timewise related to transient bursts of blood G-CSF and BAFF concentrations, suggesting that these neutro- and lymphopoiesis growth factors play a role in emergence of rituximab-induced LON, and that inflammation may be a trigger for G-CSF production during LON.

Dysfunctional Immune System Reconstitution After Rituximab Exposure In Utero

Rituximab is an antibody that binds to B-lymphocytes and is increasingly used during pregnancy. As an immunoglobulin G, it will transfer across the placenta. Previous case reports describe a diversity of clinical presentations in neonates born following rituximab exposure in utero. Our case is the first to offer the long-term experience in the care of an infant with severe neutropenia and prolonged profound hypogammaglobulinemia and class-switching B cell defect after in utero rituximab exposure.

Non-late-onset neutropaenia following treatment of multiple sclerosis with ocrelizumab

Late-onset neutropaenia is defined as an absolute neutrophil count of <1.5×103cells/μL starting>4 weeks after the last dose of rituximab, in the absence of other identifiable causes. Late-onset neutropaenia is a rare adverse reaction to rituximab (observed in approximately 5% of patients). Rheumatic diseases constitute the main indication for rituximab; in these patients, neutropaenia appears after a mean of>28 days. Ocrelizumab is another monoclonal antibody that binds to CD20 (a glycosylated phosphoprotein mainly expressed on the membranes of B-lymphocytes); in January 2018, it was approved for the treatment of relapsing-remitting and primary progressive multiple sclerosis. We present a case of neutropaenia following intravenous infusion of ocrelizumab in a patient with primary progressive multiple sclerosis who presented with neutropaenic fever, herpetic stomatitis, and ecthyma gangrenosum only 20 days after infusion.

Review on Databases and Bioinformatic Approaches on Pharmacogenomics of Adverse Drug Reactions

Pharmacogenomics has been used effectively in studying adverse drug reactions by determining the person-specific genetic factors associated with individual response to a drug. Current approaches have revealed the significant importance of sequencing technologies and sequence analysis strategies for interpreting the contribution of genetic variation in developing adverse reactions. Advance in next generation sequencing and platform brings new opportunities in validating the genetic candidates in certain reactions, and could be used to develop the preemptive tests to predict the outcome of the variation in a personal response to a drug. With the highly accumulated available data recently, the in silico approach with data analysis and modeling plays as other important alternatives which significantly support the final decisions in the transformation from research to clinical applications such as diagnosis and treatments for various types of adverse responses.

Predicting Infection Risk in Multiple Sclerosis Patients Treated with Ocrelizumab: A Retrospective Cohort Study

BACKGROUND

Ocrelizumab safety outcomes have been well evaluated in clinical trials and open-label extension (OLE) studies. However, risk factors for infection in patients with multiple sclerosis (MS) receiving ocrelizumab have not been extensively studied in the real-world setting.

OBJECTIVE

The aim of this study was to examine factors determining risk of self-reported infections and antimicrobial use in patients receiving ocrelizumab for MS.

METHODS

A retrospective, observational cohort study was conducted in patients receiving ocrelizumab at the Royal Melbourne Hospital. Infection type and number were reported by patients, and the associations of potential clinical and laboratory risk factors with self-reported infection and antimicrobial use were estimated using univariate and multivariable logistic regression models.

RESULTS

A total of 185 patients were included in the study; a total of 176 infections were reported in 89 patients (46.1%), and antimicrobial use was identified in 47 patients (25.3%). In univariate analyses, a higher serum IgA was associated with reduced odds of infection (OR 0.44, 95% CI 0.25-0.76). In multivariable analyses, older age (OR 0.94, 95% CI 0.88-0.99), higher serum IgA (OR 0.37, 95% CI 0.17-0.80) and higher serum IgG (OR 0.81, 95% CI 0.67-0.99) were associated with reduced odds of infection. Older age (OR 0.85, 95% CI 0.75-0.96) and higher serum IgA (OR 0.23, 95% CI 0.07-0.79) were associated with reduced odds of antimicrobial use, whilst longer MS disease duration (OR 1.22, 95% CI 1.06-1.41) and higher Expanded Disability Status Scale (EDSS) score (OR 1.99, 95% CI 1.02-3.86) were associated with increased odds of antimicrobial use.

CONCLUSIONS

Higher serum IgA and IgG and older age were associated with reduced odds of infection. Our findings highlight that infection risk is not uniform in patients with MS receiving ocrelizumab and substantiate the need to monitor immunoglobulin levels pre-treatment and whilst on therapy.

Incidence, Clinical Features, and Outcomes of Late-Onset Neutropenia From Rituximab for Autoimmune Disease

OBJECTIVE

Late-onset neutropenia (LON) is an underrecognized complication of rituximab treatment. We undertook this study to describe its incidence, risk factors, clinical features, management, and recurrence.

METHODS

We conducted a single-center retrospective cohort study of 738 adult patients with autoimmune disease who were treated with rituximab to induce continuous B cell depletion. The primary outcome measure was LON, defined as an unexplained absolute neutrophil count of <1,000 cells/µl during B cell depletion. Secondary outcome measures included incidental diagnosis, fever, sepsis, filgrastim use, and recurrent LON. We assessed predictors of LON using Cox proportional hazards regression models. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) were calculated.

RESULTS

We identified 107 episodes of LON in 71 patients. The cumulative incidence at 1 year of B cell depletion therapy was 6.6% (95% CI 5.0-8.7). The incidence rate during the first year was higher compared to thereafter (7.2 cases per 100 person-years [95% CI 5.4-9.6] versus 1.5 cases per 100 person-years [95% CI 1.0-2.3]). Systemic lupus erythematosus and combination therapy with cyclophosphamide were each independently associated with an increased risk of LON (adjusted HR 2.96 [95% CI 1.10-8.01] and 1.98 [95% CI 1.06-3.71], respectively). LON was not observed in minimal change disease or focal segmental glomerulosclerosis. The majority of episodes (59.4%) were asymptomatic. Fever and sepsis complicated 31.3% and 8.5% of episodes, respectively. Most patients (69%) were treated with filgrastim. Rituximab rechallenge occurred in 87% of patients, of whom 21% developed recurrent LON.

CONCLUSION

LON is common and often incidental. Most cases are reversible and respond well to filgrastim. However, LON can be associated with serious infections and thus warrants vigilant monitoring.

Risiken und Chancen von Immuntherapien in Zeiten der Coronavirus-2019-Pandemie

Immuntherapien stellen die essenzielle Grundlage der Behandlung von neuroinflammatorischen Erkrankungen dar. In Zeiten der Coronavirus-2019 (COVID-19)-Pandemie ergibt sich im klinischen Alltag jedoch zunehmend die Frage, ob eine Immuntherapie bei neurologischen Patienten aufgrund des potenziellen Infektionsrisikos eingeleitet, intensiviert, pausiert oder gar beendet werden sollte. Unsicherheit besteht v. a. deshalb, weil verschiedene nationale und internationale Fachgesellschaften diesbezüglich unterschiedliche Empfehlungen veröffentlichten. In diesem Artikel soll ein Überblick über die Wirkmechanismen von Immuntherapien und den daraus abzuleitenden Infektionsrisiken in Bezug auf COVID-19 (durch den Coronavirus verursachte Erkrankung) gegeben werden. Potenzielle Chancen und vorteilhafte Effekte einzelner Substrate in der Akuttherapie von COVID-19 werden diskutiert.

Merits and culprits of immunotherapies for neurological diseases in times of COVID-19

Immunosuppression and immunomodulation are valuable therapeutic approaches for managing neuroimmunological diseases. In times of the Coronavirus disease 2019 (COVID-19) pandemic, clinicians must deal with the question of whether immunotherapy should currently be initiated or discontinued in neurological patients. Uncertainty exists especially because different national medical associations publish different recommendations on the extent to which immunotherapies must be continued, monitored, or possibly switched during the current pandemic. Based on the most recently available data both about the novel coronavirus and the approved immunotherapies for neurological diseases, we provide an updated overview that includes current treatment strategies and the associated COVID-19 risk, but also the potential of immunotherapies to treat COVID-19.

Late-Onset Neutropenia after Rituximab Treatment for Adult-Onset Nephrotic Syndrome

A 41-year-old woman developed nephrotic syndrome at the age of 32 and was diagnosed with minimal change nephrotic syndrome based on a renal biopsy. Although remission was achieved with administration of prednisolone (PSL) and cyclosporine, the nephrotic syndrome recurred. She was also started on rituximab (RTX). She developed late-onset neutropenia after RTX treatment (R-LON) and improved 17 days later. Although the majority of R-LON cases undergo spontaneous remission, cases of death have been reported. This report is intended to warn about R-LON, since the use of RTX for adult-onset nephrotic syndrome is expected to increase in the future.

Chemotherapy-Free Initial Treatment of Advanced Indolent Lymphoma Has Durable Effect With Low Toxicity: Results From Two Nordic Lymphoma Group Trials With More Than 10 Years of Follow-Up

PURPOSE

For indolent lymphoma, the optimal timing, sequence, and choice of therapeutic regimens remain a matter of debate. In two Nordic Lymphoma Group randomized trials, symptomatic or clearly progressing patients were treated first line with a rituximab-containing regimen without chemotherapy. The purpose of this study was to assess long-term survival, risk of transformation, and need of new therapies.

METHODS

Data were collected at cross-sectional follow-up for 321 patients with indolent lymphoma (84% with follicular lymphomas [FL]) included in one of two Nordic Lymphoma Group trials (accrual 1998 to 1999 and 2002 to 2008). All patients received first-line therapy with one or two cycles of four weekly infusions of rituximab 375 mg/m2, and 148 were randomly allocated to the addition of interferon alfa-2a. Follow-up data were retrieved from initial trial databases and medical records on repeated clinical evaluations.

RESULTS

At the end of follow-up, 73% of patients were alive, with a median follow-up after random assignment of 10.6 years. Among all, 36% (38% with FL) had never needed chemotherapy. For patients with FL who required new therapy within 24 months because of early disease progression, the 10-year survival rate was 59% versus 81% for those with longer remission. Interferon was not shown to improve long-term outcome. Transformation was diagnosed in 20% of all patients (2.4% per person-year) and in 18% with FL. An additional malignancy was found in 12%.

CONCLUSION

Approximately one third of patients with symptomatic indolent lymphoma (30% with FL, 23% without FL) did not need new therapy in the long term after first-line rituximab without chemotherapy. In the entire cohort, 10-year survival was excellent with no major safety issues, which suggests that chemotherapy can be delayed safely in the majority of patients.

Drug-Induced Hematological Cytopenia in Kidney Transplantation and the Challenges It Poses for Kidney Transplant Physicians

Drug-induced hematological cytopenia is common in kidney transplantation. Various cytopenia including leucopenia (neutropenia), thrombocytopenia, and anemia can occur in kidney transplant recipients. Persistent severe leucopenia or neutropenia can lead to opportunistic infections of various etiologies. On the contrary, reducing or stopping immunosuppressive medications in these events can provoke a rejection. Transplant clinicians are often faced with the delicate dilemma of balancing cytopenia and rejection from adjustments of immunosuppressive regimen. Differentials of drug-induced cytopenia are wide. Identification of culprit medication and subsequent modification is also challenging. In this review, we will discuss individual drug implicated in causing cytopenia and correlate it with corresponding literature evidence.

Rituximab-mediated late-onset neutropenia in systemic lupus erythematosus – distinct roles of BAFF and APRIL

Objective

Rituximab-mediated late-onset neutropenia (LON) has been described in various diseases. We investigated its occurrence, consequences and contributing factors in patients with systemic lupus erythematosus (SLE).

Methods

Rituximab-treated patients from the Karolinska University Hospital ( n = 107) were surveyed. LON was defined as an absolute neutrophil count <1500 cells/μl, occurring four weeks to two years following rituximab treatment, or later during sustained B-cell depletion. Serum levels of B-cell-related cytokines and growth factors of the myeloid lineage were determined using enzyme-linked immunosorbent assay.

Results

Thirty-two patients (29.9%) developed LON after a median time of 201.5 days. Thirteen patients were admitted to the hospital; 10 due to fever. Three patients developed critical conditions. BAFF levels increased from baseline (median: 0.62 ng/ml) to the post-treatment evaluation (median: 1.16 ng/ml; p < 0.001); post-treatment levels were higher in the LON group ( p = 0.021). APRIL levels were higher in the LON group both at baseline (median: 1.54 versus 1.15 ng/ml; p = 0.027) and post-treatment (median: 2.39 versus 1.11 ng/ml; p = 0.011). IL-6 and GM-CSF levels decreased in the non-LON group ( p < 0.001), but not in LON patients. High baseline disease activity predicted LON development (OR: 4.1; 95% CI: 1.1–15.2 for SLEDAI-2K > 8). No association with neutropenia prior to rituximab treatment was documented.

Conclusion

Post-rituximab LON was a common complication. Although the phenomenon was predominantly self-limiting, several patients developed severe conditions. Distinct roles of BAFF and APRIL are implicated: BAFF may contribute to LON development, whereas high APRIL levels may be predictive. Rituximab-treated SLE patients should be monitored for neutrophil counts, fever and infections.

Late-onset neutropenia and neurological relapse, during long-term rituximab therapy in myelin oligodendrocyte glycoprotein-antibody spectrum disorder

Late-onset neutropenia after rituximab therapy (LONART) is defined as a fall in the absolute neutrophil count below 500/mm3 at least 3 weeks after rituximab infusion, in the absence of any other explanation. LONART is rare during dysimmune conditions but can be life-threatening. We report on two patients with LONART and associated neurological relapse occurring in myelin oligodendrocyte glycoprotein (MOG)-antibody spectrum disorders. Rituximab was reintroduced in one patient, while the second patient was switched to tocilizumab. LONART can occur during anti-MOG spectrum disorders. Neurologists should be aware of this rare and treatable complication. Regular monitoring of blood cell counts is needed, and patients should be informed of the need to consult their physician if symptoms of infection appear.

Pharmacokinetically-targeted dosed everolimus maintenance therapy in lymphoma patients

BACKGROUND

Everolimus, an mTOR inhibitor, is active in refractory lymphomas. However, toxicity with flat dosing limits its usage. Speculatively, pharmacokinetically-targeted dosing could improve tolerability. Therefore, we studied serum-trough dosing with rituximab as maintenance after high-dose cyclophosphamide (HDC) consolidation in lymphoma patients.

PATIENTS/METHODS

After HDC, everolimus was dosed to serum trough levels (goal 3-15 ng/mL), with quarterly rituximab infusions for 1 year while maintaining < grade II non-hematologic and < grade III hematologic toxicities. Adult patients in first PR/CR with: mantle cell, transformed, double-hit, or high risk chronic lymphocytic leukemia or in second PR for any relapsed B cell lymphoma were eligible. Prophylaxis was given for encapsulated organisms, HSV and PCP. Serum IgG levels were maintained > 500 mg/dL.

RESULTS

49 patients, median age: 59.0 years enrolled; MCL (26), CLL (10), transformed lymphoma (7), and other histologies (6). During the life of the study, the most frequent everolimus dosing has been 2.5 mg daily or 2.5 mg every other day; at these doses, serum levels are within the therapeutic range and non-hematologic toxicity is rare. At a median follow-up of 27.1 months, three patients remain on active therapy. Two patients withdrew secondary to potentially-attributable adverse events including a bacterial pneumonia and a viral pneumonia; this low rate of discontinuation compares well to other long-term everolimus trials. While a 58 and 76% EFS at 30 months for the entire cohort and MCL cohort, respectively, compares similarly to previously published HDC/rituximab data, longer follow-up is required.

CONCLUSIONS

Pharmacokinetically-targeted dosing appears to increase everolimus tolerability. This finding may be applicable to other patient populations.

Description of late onset neutropenia in indolent lymphoma patients treated with bendamustine plus rituximab

Bendamustine (B) associated with rituximab (R) is widely described in literature for the management of patients with chronic lymphoid leukaemia (CLL) and indolent non-Hodgkin lymphoma. Safety data regarding late hematotoxicity such as late onset neutropenia (LON) are scarce. The aim of our study was to assess the incidence and to identify risk factors for LON in patients with indolent non-Hodgkin lymphoma and CLL treated with B and R (B-R). One hundred forty five patients were treated with B-R as first or second line. Patients with neutropenia prior induction treatment, treated beyond second line and relapsing within 3 months after the end of induction treatment, were excluded. Patients receiving at least 1 cycle of B-R and having LON during follow-up period were included and considered as eligible for toxicity assessment. A complete blood count was performed 4 weeks after the last cycle of induction treatment and thereafter every 3 months for 1 year. Thirty six patients were identified in our cohort (incidence of 25%), mostly affected by CLL (n = 11) and follicular lymphoma (FL) (n = 15). During follow-up, 84 events of LON were recorded, 61% and 39% were of grades 1/2 and 3/4, respectively. No episode of febrile neutropenia was documented. Amongst 13 of the 15 patients with FL undergoing R maintenance, 8 had treatment discontinuation because of LON. Median time for LON (grade > 2) and time to recovery (grade < 3) were of 11.2 and 17.3 weeks, respectively. One year after B-R induction, LON persisted in 4 patients. The risk of LON was increased both in patients with FL or CLL and performance status >1. The LON in B-R treated patients is clinically relevant. Close clinical and biological follow-up and treatment prophylaxis (eg, valaciclovir and cotrimoxazole) especially for FL patients undergoing maintenance with R monotherapy seems relevant.

Effect of FCGR polymorphism on the occurrence of late-onset neutropenia and flare-free survival in rheumatic patients treated with rituximab

Background

The causes and mechanisms of late-onset neutropenia (LON) following rituximab treatment in patients with rheumatic diseases are not known. In this study, we aimed to investigate the role of established Fcγ receptor gene (FCGR) polymorphisms and B-cell-activating factor (BAFF) gene promoter polymorphisms for the development of LON and for the efficacy of rituximab in patients with rheumatic diseases.

Methods

A single-center case-control retrospective study was nested in a cohort of 214 consecutive patients with rheumatic diseases treated with rituximab. Eleven patients presented with LON. Fifty non-LON control subjects were matched by diagnosis, age, sex, and treatments. Single-nucleotide polymorphisms of FCGR (FCGR2A 131H/R, FCGR2B 232I/T, FCGR3A 158V/F) and BAFF promoter polymorphism −871C/T were analyzed with polymerase chain reaction-based techniques, and serum immunoglobulin M (IgM) and BAFF levels were analyzed by enzyme-linked immunosorbent assay. Flare-free survival was related to LON occurrence and polymorphisms.

Results

The FCGR3A V allele, but not other FCGR polymorphisms, correlated with the occurrence of LON; each V allele conferred a fourfold increased OR for LON (p = 0.017). FCGR3A 158V/V and presentation with LON were associated with a longer flare-free survival (p = 0.023 and p = 0.031, respectively). FCGR3A 158V/V was related to lower IgM levels (p = 0.016). Serum BAFF levels showed no relationship with LON and BAFF −871C/T promoter polymorphism. There was a tendency toward longer flare-free survival in patients with the BAFF −871T/T allotype compared with the C/T or C/C allotypes (p = 0.096).

Conclusions

The results of the present study suggest that presentation with LON may be a result of the intrinsic efficacy of rituximab in patients with rheumatic diseases. LON could indicate a longer biological and therapeutic activity of rituximab modulated by a certain genotypic polymorphism: the high-affinity FCGR3A V allele. This genotype and the occurrence of LON are both related to longer flare-free survival, suggestive of common mechanisms for LON and duration of response to rituximab. The role of the BAFF −871C/T promoter polymorphism in LON occurrence is unclear.

Current therapy guidelines for Waldenstrom's macroglobulinaemia

Waldenstrom's macroglobulinaemia (WM) is a B-cell neoplasm in which bone marrow is infiltrated by lymphoplasmacytic cells that secrete monoclonal immunoglobulin M (IgM). More than a decade ago, specific criteria were agreed to define diagnosis and symptomatic disease requiring therapy; however, treatment recommendations change as new options emerge. Treatment decisions consider specific disease characteristics (burden of disease, IgM levels, presence of cytopenias) and patient characteristics (age, comorbidities, toxicity). Recently, the impact of specific mutations (in MYD88 and CXCR4) in response to specific therapies has been reported, and this may affect treatment decisions in the future. Chemo-immunotherapy combinations based on rituximab with cyclophosphamide/dexamethasone, bendamustine or bortezomib/dexamethasone are indicated for most patients. The BTK inhibitor ibrutinib was recently approved for patients with WM, and is a new option for selected newly diagnosed or relapsing patients. New B-cell receptor inhibitors, second-generation proteasome inhibitors and mammalian target of rapamycin inhibitors are promising; however, more data are needed from high-quality clinical trials.

Rituximab-Related Late-Onset Neutropenia in Kidney Transplant Recipients Treated for Antibody-Mediated Acute Rejection

OBJECTIVES

Kidney transplant is a new area for use of rituximab, which is being used to treat acute antibody-mediated rejection or as an induction agent in ABO- or HLA-incompatible grafts. We report on late-onset neutropenia in rituximab-treated kidney transplant recipients with antibody-mediated rejection.

MATERIALS AND METHODS

This observational prospective study was performed on kidney transplant recipients with clinically suspicious or biopsy-proven antibody-mediated rejection treated with plasmapheresis plus intravenous immunoglobulin with (cases) or without (controls) rituximab.

RESULTS

Compared with none of the controls, 4 of 6 patients (66.7%) in the rituximab-treated group experienced late-onset neutropenia 35 to 93 days after the last dose of rituximab. The course of neutropenia was complicated by endocarditis in 1 patient, resulting in his death just because of a lack of valvular surgery.

CONCLUSIONS

Increased use of rituximab to treat antibody-mediated rejection among kidney transplant recipients requires attention to its late-onset adverse event, neutropenia. Although asymptomatic in some patients, kidney transplant recipients treated concomitantly with plasmapheresis and mycophenolate mofetil are predisposed to hypogammaglobulinemia, and monitoring of patients for infections is required.

Immune pancytopenia after chemotherapy in a patient with diffuse large B-cell lymphoma

During treatment for malignant lymphoma, cytopenia can develop for several reasons. In the treatment of cytopenia, various possibilities should be considered because inadequate treatment causes exacerbation of cytopenia and can lead to fatal conditions, such as infection and bleeding. Herein, we describe immune pancytopenia 3 months after the last exposure to chemotherapy in a patient with diffuse large B-cell lymphoma (DLBCL). She suffered from severe pancytopenia after two courses of rituximab and bendamustine therapy for a second relapse of DLBCL. Immune pancytopenia was diagnosed with bone marrow tests and the presence of autoantibodies; it promptly resolved after initiation of prednisolone therapy. Clinicians should be aware of immune cytopenia and monitor for it carefully, even if patients have already finished chemotherapy treatment.

B Cell Therapies, Approved and Emerging: a Review of Infectious Risk and Prevention During Use

The development of B cell-targeted biologics represents a major advance in the treatment of autoimmune rheumatic diseases. As with other immunosuppressive agents, risk of infection is a key clinical concern. This review summarises safety data from 15 years of experience of rituximab in autoimmune diseases with a particular focus on opportunistic infection and class-specific complications and infection risk. Rarely, cases of progressive multifocal leucoencephalopathy in rituximab-treated patients (5/100 000) have accumulated over time although no proven causal association has yet been shown. With repeat cycles of therapy, hypogammaglobulinaemia has been observed in a larger proportion of patients and is associated with increased risk of serious infections. The infection profile of the newer B cell-targeted agent, belimumab, in patients with active systemic lupus erythematosus is also discussed. Data from registries are needed to extend insights further and also to evaluate for any impact with the difference in mode of action of belimumab and infection risk in this population.

How we diagnose and treat neutropenia in adults

Neutropenias (NPs), being acute and often transient, or chronic, range from life-threatening conditions with very low absolute neutrophil blood counts (ANC) to disorders characterized by only mild NP and of no obvious significance for health. Many are caused by genetic variations/mutations, e.g. the benign familial NP and the chronic severe NPs (e.g. Kostmann disease). Some of the latter are associated with various bodily malformations. Many of the mild-to-moderate NPs are signs of underlying disorders that need specialized treatments (e.g. HIV, hepatitis, autoimmune disorders, the large granular lymphocyte syndrome). We provide here means for the evaluation of a previously unknown NP, suggest a triage and treatments.

Critical appraisal of rituximab in the maintenance treatment of advanced follicular lymphoma

Rituximab is an IgG1, chimeric monoclonal antibody specifically designed to recognize the CD20 antigen expressed on the surface of normal and malignant B-lymphocytes, from the B-cell precursor to the mature B-cells of the germinal center, and by most neoplasms derived from B-cells. After 2 decades of use, rituximab is firmly positioned in the treatment of follicular lymphoma (FL), both in the front line and in the relapsing disease, improving previous results by including it in classical chemotherapy regimens. However, the pharmacology of rituximab continues to generate controversial issues especially regarding the mechanisms of action in vivo. The contribution of rituximab as a maintenance treatment in FL has been significant progress in the management of this disease without an increase in side effects or a decrease in the quality of life of patients. With the widespread use of rituximab, there are new security alerts and side effects not previously detected in the pivotal trials that clinicians should learn to recognize and manage. In this article, we will review the pharmacokinetics and pharmacodynamics of rituximab, the management issues in the treatment of advanced FL focusing on maintenance rituximab, its long-term efficacy and safety profile, and its effect on the quality of life.

Rituximab as maintenance therapy for ANCA associated vasculitis: how, when and why?

ANCA-associated vasculitides (AAV) are chronic autoimmune diseases characterized by inflammation and destruction of small vessels. Rituximab is now licensed for use as a remission-induction agent in the treatment of these disorders. During recent years, several non-controlled studies have suggested that rituximab may be of value in maintaining disease remission in AAV. In these series, 3 techniques have been tried: "watch-and-wait", repeated cycles in fixed intervals, or administration based on proposed biomarkers. More importantly, the results of the MAINRITSAN trial showed that this anti-CD20 agent is superior to azathioprine for preventing major relapses in AAV. This review summarizes current information regarding the effectiveness, timing, dosing, duration and safety of rituximab as a valid option for remission maintenance.

Successful use of Rituximab in a patient with recalcitrant multisystemic eosinophilic granulomatosis with polyangiitis

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare eosinophil-rich disorder characterised by necrotising granulomatous inflammation affecting small to medium sized vessels. Extrapulmonary manifestations can be life-threatening when heart, central nervous system (CNS), gastrointestinal tract or kidneys are affected. We describe a case of a 56-year-old woman with a long-standing history of asthma, who presented with an acute sudden painless loss of vision after she had been recently diagnosed with EGPA and induced with pulse steroids and cyclophosphamide. The patient had a complicated hospital course with multisystemic involvement of active vasculitis, involving heart, kidneys, muscles, eyes and CNS. The patient's devastating condition responded remarkably to Rituximab. The role of Rituximab in EGPA is not yet proven. Few cases are reported in the literature about the role of Rituximab in EGPA, of which only one described retinal artery occlusion as a presentation of a recently treated patient with EGPA.

Low-dose rituximab in the treatment of acquired haemophilia

OBJECTIVE AND IMPORTANCE

Acquired haemophilia is a rare hemorrhagic disease caused by inhibitory autoantibodies against coagulation factor VIII. Rituximab has become a popular choice for immunosuppressive therapy in acquired haemophilia, almost with the same schedule of 375 mg/m(2) per week for 4-6 doses. While the effect of low-dose rituximab has seldom been reported.

CLINICAL PRESENTATION

We report a patient, aged 88 years, who developed acquired haemophilia with severe hemorrhage and elevation of carbohydrate antigen 125 (CA125), but in the absence of a detectable cause.

INTERVENTION

We prescribed a low-dose rituximab alone (100 mg per week for a total of four infusions) for the patient, different from the conventional usage, but received a similar effect. In addition, the patient was diagnosed with immune thrombocytopenia 22 months after rituximab, while FVIII activity and activated partial thromboplastin time remained within the normal range. After four infusions of low-dose rituximab, the platelet count recovered.

CONCLUSION

At a follow-up of 34 months, the patient remains in remission without further treatment, suggesting low-dose rituximab seems to be a safe and effective regimen for the elderly patients with acquired haemophilia.

Unexpected hematologic effects of biotherapeutics in nonclinical species and in humans

Biotherapeutics are expanding the arsenal of therapeutics available for treating and preventing disease. Although initially thought to have limited side effects due to the specificity of their binding, these drugs have now been shown to have potential for adverse drug reactions including effects on peripheral blood cell counts or function. Hematotoxicity caused by a biotherapeutic can be directly related to the activity of the biotherapeutic or can be indirect and due to autoimmunity, biological cascades, antidrug antibodies, or other immune system responses. Biotherapeutics can cause hematotoxicity primarily as a result of cellular activation, cytotoxicity, drug-dependent and independent immune responses, and sequelae from initiating cytokine and complement cascades.  The underlying pathogenesis of biotherapeutic-induced hematotoxicity often is poorly understood. Nonclinical studies have generally predicted clinical hematotoxicity for recombinant cytokines and growth factors.  However, most hematologic liabilities of biotherapeutics are not based on drug class but are species specific, immune-mediated, and of low incidence. Despite the potential for unexpected hematologic toxicity, the risk-benefit profile of most biotherapeutics is favorable; hematologic effects are readily monitorable and managed by dose modification, drug withdrawal, and/or therapeutic intervention.  This article reviews examples of biotherapeutics that have unexpected hematotoxicity in nonclinical or clinical studies. 

Long-term outcomes of pediatric living donor liver transplantation in Japan: an analysis of more than 2200 cases listed in the registry of the Japanese Liver Transplantation Society

The Japanese Liver Transplantation Society (JLTS) was established in 1980 in order to characterize and follow trends in patient characteristics and graft survival among all liver transplant patients in Japan. This study analyzed the comprehensive factors that may influence the outcomes of pediatric patients who undergo living donor liver transplantation (LDLT) by evaluating the largest cohort in the world. Between November 1989 and December 2010, 2224 pediatric patients underwent LDLT in Japan. There were 998 male (44.9%) and 1226 female donors (55.1%) without donor mortalities related to transplant surgery. There were 946 male (42.5%) and 1278 female (57.5%) recipients with a median age of 4.0 years (range: 13 days to 17.9 years). Cholestatic liver disease was the leading indication for LDLT (n = 1649; 76.2%), followed by metabolic disorders (n = 194; 8.7%), acute liver failure (n = 192; 8.6%) and neoplastic liver disease (n = 66; 3.0%). The 1-, 5-, 10- and 20-year patient survival rates were 88.3%, 85.4%, 82.8% and 79.6%, respectively. Blood-type incompatibility, recipient age, etiology of liver disease and transplant era were found to be significant predictors of overall survival. We are able to achieve satisfactory long-term pediatric patient survival outcomes in the JLTS series without compromising the living donors.

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.

Idiosyncratic adverse drug reactions: current concepts

Idiosyncratic drug reactions are a significant cause of morbidity and mortality for patients; they also markedly increase the uncertainty of drug development. The major targets are skin, liver, and bone marrow. Clinical characteristics suggest that IDRs are immune mediated, and there is substantive evidence that most, but not all, IDRs are caused by chemically reactive species. However, rigorous mechanistic studies are very difficult to perform, especially in the absence of valid animal models. Models to explain how drugs or reactive metabolites interact with the MHC/T-cell receptor complex include the hapten and P-I models, and most recently it was found that abacavir can interact reversibly with MHC to alter the endogenous peptides that are presented to T cells. The discovery of HLA molecules as important risk factors for some IDRs has also significantly contributed to our understanding of these adverse reactions, but it is not yet clear what fraction of IDRs have a strong HLA dependence. In addition, with the exception of abacavir, most patients who have the HLA that confers a higher IDR risk with a specific drug will not have an IDR when treated with that drug. Interindividual differences in T-cell receptors and other factors also presumably play a role in determining which patients will have an IDR. The immune response represents a delicate balance, and immune tolerance may be the dominant response to a drug that can cause IDRs.