Predictors of hypogammaglobulinemia during rituximab maintenance therapy in rheumatoid arthritis: A 12-year longitudinal multi-center study

Hypogammaglobulinemia and Infection Events in Patients with Autoimmune Diseases Treated with Rituximab: 10 Years Real-Life Experience

OBJECTIVES

To investigate predictors of hypogammaglobulinemia (HGG) and severe infection event (SIE) in patients with autoimmune disease (AID) receiving rituximab (RTX) therapy.

METHODS

This was a retrospective study conducted in a tertiary medical center in China. Predictors of HGG or SIE were assessed using Cox analysis. Restricted cubic spline (RCS) analysis was applied to examine the correlation between glucocorticoid (GC) maintenance dose and SIE.

RESULTS

A total of 219 patients were included in this study, with a cumulative follow-up time of 698.28 person-years. Within the study population, 117 patients were diagnosed with connective tissue disease, 75 patients presented with ANCA-associated vasculitis, and 27 patients exhibited IgG4-related disease. HGG was reported in 63.3% of the patients, where an obvious decline in IgG and IgM was shown three months after RTX initiation. The rate of SIE was 7.2 per 100 person-years. An increase in the GC maintenance dose was an independent risk factor for both hypo-IgG (HR 1.07, 95% CI 1.02-1.12, p = 0.003) and SIE (HR 1.06, 95% CI 1.02-1.1, p = 0.004). Further RCS analysis identified 7.48 mg/d prednisone as a safe threshold dose for patients who underwent RTX treatment to avoid a significantly increased risk for SIE.

CONCLUSION

HGG was relatively common in RTX-treated AID patients. Patients with chronic lung disease or who were taking ≥ 7.5 mg/d prednisone during RTX treatment were at increased risk for SIE and warrant attention from physicians.

Should complete B cell depletion be maintained in patients treated long-term with rituximab for rheumatoid arthritis?

OBJECTIVE

To determine whether persistent complete B cell (BC) depletion was associated with a better clinical response in rheumatoid arthritis (RA) patients long-term treated with rituximab (RTX).

METHODS

We conducted a retrospective study including RA patients admitted for a new infusion between 2019 and 2021. The primary endpoint was the comparison of the mean disease activity score based on 28 joints (DAS28)-CRP at each of the four last infusion visits between patients with persistent complete BC depletion (mean CD19 counts <18/µl at each of the last four visits) or without persistent complete BC depletion (mean CD19 counts of the last four visits ≥18/µl). Secondary endpoints included DAS28, pain/fatigue visual analogue scale, CRP, gammaglobulins and the frequency of self-reported RA flares.

RESULTS

Of the 126 patients in maintenance therapy with RTX [exposure period: 76 (5) months, 14 (7) infusions received], 43 (34%) had persistent complete BC depletion at each of the four last infusions. The mean DAS28-CRP calculated at each of the four last infusion visits did not significantly differ according to persistence or not of complete BC depletion. This result remained unchanged after adjusting for antibody status, number of previous therapies, number of RTX infusion and cumulative RTX dose. All secondary outcomes were also not significantly different between the two groups.

CONCLUSION

Maintaining complete BC depletion does not appear to be a therapeutic target to achieve in RA patients in long-term maintenance therapy with RTX. There is a limited benefit of monitoring CD19 in RA patients long-term treated with RTX and having achieved low disease activity/remission.

Predictors and prognostic factors influencing outcomes of anti-CD20 monoclonal antibodies in systemic lupus erythematosus: A systematic review update

BACKGROUND

Anti-C20 monoclonal antibodies (MAb), such as rituximab, are commonly used for the treatment of patients with severe or refractory systemic lupus erythematosus (SLE) but clinical outcomes are highly variable. We aimed to provide an update of a systematic review of predictive and prognostic factors of anti-CD20 MAb treatment in SLE.

METHODS

A systematic literature search was undertaken to identify predictive and prognostic factors of clinical response following treatment with anti-CD20 therapies in SLE patients. Studies examining rituximab published prior to 2015 were excluded. Risk of bias was assessed for randomized controlled trials (RCTs) using the Cochrane Collaboration (RoB2) tool for RCTs and the Quality In Prognosis Studies Tool (QUIPS) for cohort studies. A narrative synthesis of the evidence was undertaken and quality of evidence (QoE) was assessed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

From 850 studies identified, 17 studies met the inclusion criteria. A further 8 studies were identified and included through search updates. There were two post-hoc analyses of RCTs of rituximab, one RCT of ocrelizumab and one of obinutuzumab; and 16 cohort studies examining rituximab treatment. The overall QoE was low or very low. There was wide heterogeneity in definitions of clinical disease activity and outcome measures, non-standardized laboratory cut-offs, failure to account for confounders and multiple subgroup analyses of differing outcomes. B cell depletion as well as novel biomarkers, such as S100 proteins, FCGR genotype, anti-vimentin and anti-drug antibodies showed some evidence of prognostic value but QoE was limited due to moderate to high risk of bias, early phase of investigation and imprecision of results.

CONCLUSION

There has been no validation of previously identified prognostic factors to guide outcome in anti-CD20 treated lupus patients. Hypothesis-driven studies of several novel markers however, demonstrate prognostic value and require replication and validation to support their use in routine clinical practice.

PROSPERO REGISTRATION NUMBER

CRD42020220339.

Risk of severe infection associated with immunoglobulin deficiency under rituximab therapy in immune-mediated inflammatory disease

OBJECTIVES

We evaluated the risk of severe infection in patients with immune-mediated inflammatory disease (IMID) treated with RTX and with Ig deficiency.

METHODS

This was an observational, retrospective single-centre study of patients undergoing treatment with at least one rituximab (RTX) infusion for an IMID until 31 May 2020. Patients were followed up for at least 12 months after the last infusion or until severe infection or death. Ig deficiency was classified as prevalent (before RTX) or acquired (normal Ig assay results before RTX but Ig deficiency during a follow-up).

RESULTS

Of 311 patients, 10.6% had prevalent and 19.6% acquired Ig deficiency. Prevalent Ig deficiency was related to concomitant treatment with glucocorticoids (GCs), in particular with a high daily dose at baseline; and acquired Ig deficiency to cumulative dose of RTX, mean Disease Activity Score in 28 joints (DAS28), immunosuppressor or GCs therapy at baseline, diabetes mellitus and obesity. Overall, 14.5% of patients had a severe infection during follow-up, which was numerically but not statistically more frequent in patients with prevalent Ig deficiency than normal Ig level. On multivariate analysis, risk of severe infection was associated with chronic pulmonary disease, GCs dose and mean DAS28-C reactive protein. In a time-dependent analysis, risk of severe infection was not associated with Ig deficiency, either acquired or prevalent (adjusted HR 1.04 (95% CI 0.5 to 2.3), p=0.92).

CONCLUSION

Risk of severe infection was not associated with RTX-induced Ig deficiency in patients with an IMID. RTX management should be discussed according to an individual assessment of the infectious risk, especially in patients with GC therapy or chronic lung disease.

Biologics in peripheral ulcerative keratitis

Over the past two decades biologic therapies have seen a rapid uptake in the management of ocular inflammation. Peripheral ulcerative keratitis (PUK), once a harbinger of blindness and mortality in refractory rheumatological disease, is now increasingly being treated with these agents. We conducted a review to evaluate the evidence base for this application and to provide a road map for their clinical usage in PUK, including dosage and adverse effects. A literature search across Medline, Embase and Cochrane Database of Systematic Reviews was undertaken to identify all patients with PUK that were treated with a biologic in a peer viewed article. Overall, whilst the evidence base for biologic use in PUK was poor, reported cases demonstrate an increasingly powerful and effective role for biologics in refractory PUK. This was particularly the case for rituximab in PUK secondary to granulomatous with polyangiitis.

Corticosteroid-induced low immunoglobulin levels in multiple sclerosis - A confounding factor

BACKGROUND

Changes in immunoglobulin (Ig) levels may occur in association with various drugs targeting immunity, including those used to treat multiple sclerosis (MS). However, influence of high-dose corticosteroids (CS) is poorly described.

OBJECTIVE

To describe influence of disease-modifying drugs (DMD) and CS on the Ig levels.

METHODS

Monocentric retrospective study examining changes in Ig levels in relation with CS intake in a series of 304 consecutive MS patients (and 1204 samples) followed or hospitalized for 7 years in a single centre. Ig levels are routinely collected in MS patients followed in our centre.

RESULTS

IgG levels were significantly lower in MS patients exposed to CS infusion during the last 24 months. IgG levels were also lower in DMD-treated patients exposed to CS. DMD-specific decrease of IgM levels was confirmed in interaction with CS.

CONCLUSION

Stratification by CS exposure suggested that a decrease in Ig levels occurring during DMD treatment was strongly associated with CS infusion. The strong and persistent effect of CS on Ig levels could be a hidden variable and should be considered in further studies targeting Ig levels.

[Diagnosis and therapy of granulomatosis with polyangiitis and microscopic polyangiitis-2023: consensus of the Austrian society of nephrology (ÖGN) and Austrian society of rheumatology (ÖGR)]

ANCA-associated vasculitides (AAV) are rare, complex systemic diseases that are often difficult to diagnose, because of unspecific clinical symptoms at presentation. However, the clinical course may be very dramatic and even life-threatening, necessitating prompt diagnosis and treatment.Therefore, it is important to increase disease awareness among physicians and support colleagues who are not confronted with these rare diseases on a regular basis. Here, the Austrian Society of Nephrology (ÖGN) and the Austrian Society of Rheumatology (ÖGR) provide a joint consensus on how to best diagnose and manage patients with granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA).

Infectious risk when prescribing rituximab in patients with hypogammaglobulinemia acquired in the setting of autoimmune diseases

We conducted a single-centre retrospective cohort study in a French University Hospital between 2010 and 2018 to describe the risk of severe infectious event (SIE) within 2 years after the date of first rituximab infusion (T0) prescribed after the evidence of acquired hypogammaglobulinemia (gamma globulins [GG] ≤ 6 g/L) in the setting of autoimmune diseases (AID) other than rheumatoid arthritis. SIE occurred in 26 out of 121 included patients. Two years cumulative incidence rates were 12.7 % (95 % CI 5.1-23.9) in the multiple sclerosis/neuromyelitis optica spectrum disorder group (n = 48), 27.6 % (95 % CI 15.7-40.9) in the ANCA-associated vasculitis group (n = 48) and 30.6 % (95 % CI 13.1-50.3) in the 'other AID' group (n = 25). Median GG level at T0 was 5.3 g/l (IQR 4.1-5.6) in the 'SIE' group and 5.6 g/l (IQR 4.7-5.8) in the 'no SIE' group (p = 0.04). In regression analysis, risk of SIE increased with Charlson comorbidity index ≥ 3 (OR 2.77; 95 % CI 1.01-7.57), lung disease (OR 3.20; 95 % CI 1.27-7.99), GG < 4 g/L (OR 3.39; 95 % CI 1.02-11.19), concomitant corticosteroid therapy (OR 4.13; 95 % CI 1.63-10.44), previous cyclophosphamide exposure (OR 2.69; 95 % CI 1.10-6.61), a lymphocyte count < 1000 cells/µL (OR 2.86; 95 % CI 1.12-7.21) and absence of pneumococcal vaccination (OR 3.50; 95 % CI 1.41-8.70). These results may help to inform clinical decision when considering a treatment by rituximab in immunosuppressed AID patients with hypogammaglobulinemia.

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.

Real-life drug retention rate and safety of rituximab when treating rheumatic diseases: a single-centre Swiss retrospective cohort study

BACKGROUND

In Switzerland, rituximab (RTX) is licenced for the treatment of rheumatoid arthritis (RA) and ANCA-associated vasculitis (AAV) but is frequently used off-label to treat other auto-immune diseases (AID), especially connective tissue diseases (CTD). We aimed to characterise the use of RTX in AID in a real-life Swiss setting and compare RTX retention rates and safety outcomes between patients treated for RA, CTD and AAV.

METHODS

A retrospective cohort study of patients who started RTX in the Rheumatology Department for RA or AID. The RTX retention rate was analysed using Kaplan-Meier survival curves. Occurrences of serious adverse events (SAE), low IgG levels and anti-drug antibodies (ADA) were reported.

RESULTS

Two hundred three patients were treated with RTX: 51.7% had RA, 29.6% CTD, 9.9% vasculitis and 8.9% other AIDs. The total observation time was 665 patient-years. RTX retention probability at 2 years (95%CI) was similar for RA and CTD 0.65 (0.55 to 0.73), 0.60 (0.47 to 0.72) and lower for vasculitis 0.25 (0.09 to 0.45). Survival curves for RTX retention matched closely (p = 0.97) between RA and CTD patients but were lower for patients with vasculitis due to a higher percentage of induced remission. Patients with vasculitis (95%) and CTD (75%) had a higher rate of concomitant glucocorticoid use than RA (60%). Moderate to severe hypogammaglobulinaemia was observed more frequently in patients with vasculitis (35%) than with RA (13%) or CTD (9%) and was associated with an increased risk of presenting a first infectious SAE (HR 2.01, 95% CI 1.04 to 3.91). The incidence rate of SAE was 23.3 SAE/100 patient-years (36% were infectious). When searched, ADAs were observed in 18% of the patients and were detected in 63% of infusions-related SAE. 10 patients died during RTX treatment and up to 12 months after the last RTX infusion, 50% from infection.

CONCLUSION

RTX retention rates are similar for patients with RA and CTD but lower for those with vasculitis due to more frequent remission. Patients treated with RTX for vasculitis present more SAE and infectious SAE than patients with RA and CTD, potentially due to a higher use of concomitant glucocorticoids and the occurrence of hypogammaglobulinaemia.

Impact of extended interval dosing of ocrelizumab on immunoglobulin levels in multiple sclerosis

BACKGROUND

Long-term B cell depletion with ocrelizumab in multiple sclerosis (MS) is associated with severe side effects such as hypogammaglobulinemia and infections. Our study therefore aimed to assess immunoglobulin levels under treatment with ocrelizumab and implement an extended interval dosing (EID) scheme.

METHODS

Immunoglobulin levels of 51 patients with ≥24 months of treatment with ocrelizumab were analyzed. After ≥4 treatment cycles, patients chose to either continue on the standard interval dosing (SID) regimen (n = 14) or, in the case of clinically and radiologically stable disease, switch to B cell-adapted EID (n = 12, next dose at CD19⁺ B cells >1% of peripheral blood lymphocytes).

FINDINGS

Levels of immunoglobulin M (IgM) declined rapidly under ocrelizumab treatment. Risk factors for IgM and IgA hypogammaglobulinemia were lower levels at baseline and more previous disease-modifying therapies. B cell-adapted EID of ocrelizumab increased the mean time until next infusion from 27.3 to 46.1 weeks. Ig levels declined significantly in the SID group over 12 months but not in the EID group. Previously stable patients remained stable under EID as measured by expanded disability status scale (EDSS), neurofilament light chain, timed 25-foot walk (T25-FW), 9-hole peg test (9-HPT), symbol digit modalities test (SDMT), and multiple sclerosis impact scale (MSIS-29).

CONCLUSIONS

In our pilot study, B cell-adapted EID of ocrelizumab prevented the decline of Ig levels without affecting disease activity in previously stable patients with MS. Based on these findings, we propose a new algorithm for long-term ocrelizumab treatment.

FUNDING

This study was supported by the Deutsche Forschungsgemeinschaft (SFB CRC-TR-128, SFB 1080, and SFB CRC-1292) and the Hertie Foundation.

[Prevalence of persistent hypogammaglobulinemia in patients with autoimmune rheumatic disease who received treatment with Rituximab in a national medical center in Mexico]

OBJECTIVE

To describe the prevalence of persistent hypogammaglobulinemia in patients receiving Rituximab as a treatment for autoimmune rheumatological diseases.

METHODS

A transversal, retrospective and unicentric study, carried out in patients with autoimmune rheumatic diseases who were admitted to the Rheumatology service of the Hospital de Especialidades Dr. Antonio Fraga Mouret, Centro Médico Nacional La Raza, Mexico City, to receive treatment with rituximab between January 2013 and January 2018. Descriptive and inferential statistics of serum levels of immunoglobulins, clinical-demographic characteristics, diagnosis, and treatment received were performed.

RESULTS

from 262 patients with autoimmune rheumatological disease who received treatment with Rituximab; We identified 8 patients with persistent hypogammaglobulinemia (6 women and 2 men), this is a prevalence of 3.1%. No associated factors with the development of hypogammaglobulinemia were identified.

CONCLUSIONS

Until now, no associated prognostic or predictive factors have been identified with persistent hypogammaglobulinemia. Additional prospective studies are required to understand more precisely the implications of persistent hypogammaglobulinemia in patients with autoimmune diseases.

Hypogammaglobulinemia secondary to B-cell depleting therapies in neuroimmunology: Comparing management strategies

Background

Anti-CD20 agents are commonly used in MS, NMOSD, and MOGAD. Few studies have compared strategies to address hypogammaglobulinemia.

Objective

To compare strategies to manage secondary hypogammaglobulinemia in neuroimmunology patients, including reducing anti-CD20 dose and dosing frequency, IVIG/SCIG, anti-CD20 cessation, and DMT switches.

Methods

All MS, NMOSD, and MOGAD patients at our institution with hypogammaglobulinemia on anti-CD20 agents from 2001 to 2022 were analyzed. The median change in IgG, infection frequency, and infection severity before and after the treatment was calculated.

Results

In total, 257 patients were screened, and 30 had a treatment for hypogammaglobulinemia. IVIG/SCIG yielded the largest increase in IgG per year (674.0 mg/dL), followed by B-cell therapy cessation (34.7 mg/dL), and DMT switch (5.9 mg/dL). Dose reduction had the largest decrease in yearly infection frequency (2.7 fewer infections), followed by IVIG/SCIG (2.5 fewer), DMT switch (2 fewer), and reduced dosing frequency (0.5 fewer). Infection grade decreased by 1.9 for reduced dosing frequency (less severe infections), by 1.3 for IVIG/SCIG, and by 0.6 for DMT switch.

Conclusion

This data suggests that IVIG/SCIG may yield the greatest recovery in IgG while also reducing infection frequency and severity. Stopping anti-CD20 therapy and/or switching DMTs also increase IgG and may lower infection risk.

Predictors of hypogammaglobulinemia and serious infections among patients receiving ocrelizumab or rituximab for treatment of MS and NMOSD

BACKGROUND AND OBJECTIVES

Ocrelizumab and rituximab are monoclonal antibodies targeting the CD20 marker on B lymphocytes. The enhanced efficacy of B lymphocyte depleting therapies poses a greater risk of decreased immunoglobulin (Ig) levels. The rate and risk factors of hypogammaglobulinemia in MS and NMOSD patients treated with anti-CD20 therapies are unknown.

METHODS

A retrospective study was conducted among patients who received anti-CD20 therapy for the treatment of MS, NMOSD, and other related neurological disorders. The goal was to determine the incidence and risk factors of hypogammaglobulinemia and serious infections in patients receiving ocrelizumab versus rituximab. The secondary goals were to determine the rates of lymphopenia, neutropenia, and early B cell repopulation among patients on anti-CD20 therapy.

RESULTS

Overall, 184 patients (mean age 48.4 ± 13.7, 66.8% female) met inclusion criteria; 152 patients received ocrelizumab and 32 patients received rituximab. A total of 22 patients (12%) developed hypogammaglobulinemia. Patients who developed hypogammaglobulinemia were more likely to have been ≥50 years of age (p = .0275) with lower baseline IgG (p = .001) and IgA (p = .0038) levels. Serious infections were observed in 21 patients (11%) and seen more commonly in those that developed total lymphopenia (<1.0 × 109/L) and had longer duration of B-cell therapy. Multivariate analysis identified age ≥ 50 years, white race, and rituximab as independent predictors of hypogammaglobulinemia, and absolute lymphopenia as an independent risk factor for serious infections.

DISCUSSION

Among patients receiving anti-CD20 therapy, 12% of patients experienced hypogammaglobulinemia which was seen more commonly in white patients, at least 50 years old, with lower baseline IgG and IgA levels and in those treated with rituximab. Serious infections were seen more commonly in patients with total lymphopenia and longer exposure to anti-CD20 therapy.

Rituximab dose-dependent infection risk in rheumatoid arthritis is not mediated through circulating immunoglobulins, neutrophils or B cells

OBJECTIVES

Rituximab (RTX) is a safe and effective treatment for RA. A dose-dependent infection risk was found in the REDO trial. Some studies associate RTX use with higher infection risks, possibly explained by low immunoglobulin levels and/or neutropenia. Additionally, a higher infection risk shortly after RTX infusion is reported. The objectives of this study were (i) to compare incidence rates of infections between doses and over time, and (ii) to assess B-cell counts, immunoglobulin levels, neutrophil counts and corticosteroid/disease modifying rheumatic drug use as mediating factors between RTX study dose and infection risk.

METHODS

Post hoc analyses of the REDO trial were performed. Infection incidence rates between RTX dosing groups and between time periods were compared using Poisson regression. A step-wise mediation analysis was performed to investigate if any of the factors mentioned above act as a mediator in the observed dose-dependent difference in infection risk.

RESULTS

The potential mediators that were investigated (circulating B-cell counts, immunoglobulin levels, neutrophil counts and drug use) did not explain the dose-dependent infection risk observed in the REDO trial. Additionally, a trend towards a time-dependent infection risk was found, with higher infection rates shortly after RTX infusion.

CONCLUSIONS

These secondary analyses of the REDO trial confirmed the observed dose-dependent infection risk. Additionally, we found that infection risks were higher shortly after RTX infusion. However, a mediating pathway was not found.

Comparative effectiveness of natalizumab versus ocrelizumab in multiple sclerosis: a real-world propensity score-matched study

Background

For treatment of relapsing-remitting multiple sclerosis (RRMS), a broad range of disease-modifying therapies (DMT) is available. However, few comparative effectiveness studies between different drugs have been performed.

Objectives

This study aimed to compare the efficacy and treatment continuation of natalizumab and ocrelizumab in a real-world cohort of patients with relapsing-remitting multiple sclerosis (RRMS) from two German university hospitals.

Methods

We performed a retrospective analysis of RRMS patients who initiated treatment with natalizumab or ocrelizumab between January 2016 and April 2019 at the German university hospitals of Mainz and Düsseldorf. Bayesian propensity score matching was conducted to correct for differences in baseline characteristics. Our primary outcome was no evidence of disease activity [NEDA-3: no relapses, no confirmed disability progression, and no magnetic resonance imaging (MRI) activity] and its subcomponents. Secondary outcomes included measurement of neurofilament light chain (NfL) in serum, analysis of premature discontinuation, and evidence of rebound activity in patients switching from natalizumab to ocrelizumab.

Results

We identified 63 patients starting treatment with natalizumab and 76 patients starting with ocrelizumab. Binary logistic regression showed that treatment with natalizumab or a higher number of relapses in the previous year were independently associated with a higher risk for relapses. Patients receiving natalizumab had a higher probability of premature discontinuation of therapy (p = 0.002). After propensity score matching of the two treatment arms, 55 patients remained per group. NEDA-3 after 30 months of follow-up was reached by 53.1% in the ocrelizumab group and 36.1% in the natalizumab group (p = 0.177). Ocrelizumab was superior to natalizumab concerning the occurrence of relapses in log-rank test (p = 0.019). NfL levels in serum were low under both treatments. Patients who switched from natalizumab to ocrelizumab showed no increased rebound activity.

Discussion

This study provides class IV evidence that treatment of RRMS patients with ocrelizumab and natalizumab show comparable effectiveness in combined endpoints, while ocrelizumab might be more effective in preventing the occurrence of relapses.

Intravenous ofatumumab treatment of multiple sclerosis and related disorders: An observational study

BACKGROUND

Ofatumumab is an anti-CD20 monoclonal antibody approved for subcutaneous administration for the treatment of relapsing multiple sclerosis (MS), but intravenously administered ofatumumab has been investigated in a phase 2 trial and used off-label. The objective of the present study was to assess disease activity and side effects in relation to longer-term intravenous ofatumumab treatment of MS and related disorders.

METHODS

We conducted a retrospective study of patients treated off-label with intravenous ofatumumab for MS, neuromyelitis optica spectrum disease (NMOSD) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) at the Danish Multiple Sclerosis Center. Data was retrieved from the Danish Multiple Sclerosis Registry and through medical chart review.

RESULTS

Fifty patients were identified with a median treatment duration of 2.2 years. Annualized relapse rate decreased from 1.03 at baseline to 0.38 during ofatumumab treatment. At 24 months, the probability of having experienced a relapse was 55% and confirmed disability worsening 7%. Frequency of infusion-related reactions was 86% during the first infusion and 42% during the last infusion. Six experienced infections requiring hospitalization.

CONCLUSION

Our data indicate a reduction of relapse frequency, stabilization of disability worsening and an acceptable safety profile, although we observed a higher frequency of infusion reactions compared to data from other intravenously administered anti-CD20 monoclonal antibodies. The study supports a class effect of anti-CD20 monoclonal antibodies and the hypothesis that complement activation may be associated to a higher frequency of infusion related reactions.

Secondary rituximab-associated versus primary immunodeficiencies: The enigmatic border

Rituximab (RTX), a chimeric monoclonal antibody targeting CD20-positive cells, is a valuable treatment option for malignant and benign immune-related disorders. The rationale of targeting the CD20 antigen relies on depletion of both healthy and autoreactive/malignant CD20-espressing cells, but normal B-cell reconstitution is expected within months after treatment. Nevertheless, a number of recent studies have documented prolonged B-cell deficiency associated with new-onset hypogammaglobulinemia in patients receiving RTX. Awareness of post-RTX hypogammaglobulinemia has become wider among clinicians, with a growing number of reports about the increased incidence, especially in children. Although these patients were previously regarded as affected by secondary/iatrogenic immunodeficiency, atypical clinical and immunological manifestations (e.g., severe or opportunistic infections; prolonged B-cell aplasia) raise concerns of delayed manifestations of genetic immunological disorders that have been unveiled by B-cell perturbation. As more patients with undiagnosed primary immune deficiency receiving RTX have been identified, it remains the challenge in discerning those that might display a higher risk of persistent RTX-associated hypogammaglobulinemia and need a tailored immunology follow-up. In this review, we summarize the principal evidence regarding post-RTX hypogammaglobulinemia and provide a guideline for identifying patients at higher risk of RTX-associated hypogammaglobulinemia that could harbor an inborn error of immunity.

Rituximab-Induced Hypogammaglobulinemia and Risk of Infection in Neuromyelitis Optica Spectrum Disorders

Background and Objectives

To investigate the frequency and predictors of hypogammaglobulinemia during long-term rituximab (RTX) treatment in patients with neuromyelitis optica spectrum disorder (NMOSD) and its association with infections.

Methods

We retrospectively reviewed the data of patients with NMOSD who received RTX through the maintenance regimen based on memory B-cell detection for at least 1 year from 2006 to 2021 at an institutional referral center for NMOSD.

Results

A total of 169 patients received a median of 10 courses (range 1–27) of RTX reinfusion after induction over a median of 8 (range, 1–15) years. Their mean serum immunoglobulin (Ig)G level began to decline significantly after 2 years of treatment, steadily declined at a rate of 2%–8% per year for the following 8 years, and then plateaued after 10 years. The proportion of patients with hypo-IgG (<6 g/L) increased from 1.2% after 1 year of treatment to 41% after 14 years of treatment. While being treated with RTX, 58 (34%) patients had 114 infections, of whom 14 (8%) patients had 15 severe infections. Multivariable logistic regression analyses identified duration of RTX treatment in years (odds ratio [OR] 1.234, 95% confidence interval [CI] 1.015–1.502), mean annual RTX dose (OR 0.063, 95% CI 0.009–0.434), history of mitoxantrone (OR 3.318, 95% CI 1.109–9.93), hypo-IgG at baseline (OR 40.552, 95% CI 3.024–543.786), and body mass index >25 kg/m² (OR 4.798, 95% CI 1.468–15.678) as independent predictors of hypo-IgG. The risk of infection during RTX treatment was independently associated with high Expanded Disability Status Scale scores (OR 1.427, 95% CI 1.2–1.697) and relapses during RTX treatment (OR 1.665, 95% CI 1.112–2.492), but not with hypogammaglobulinemia.

Discussion

Over 14 years of long-term RTX treatment, IgG levels gradually decreased, and the frequency of hypo-IgG increased to 41% of the patients. Patients with prolonged memory B-cell depletion after RTX, previous mitoxantrone history, hypo-IgG at baseline, or obesity were at risk of developing RTX-induced hypogammaglobulinemia. Nevertheless, infection rates remained low during treatment, and reduced immunoglobulin levels were not associated with an increased incidence of infections.

Hematologic side effects of biologics and kinase inhibitors used in rheumatologic diseases: a review of the current evidence

Treatment options for various rheumatologic diseases have been limited until the introduction of biologic agents and kinase inhibitor therapy in recent decades. Since their arrival, they have steadily been integrated into routine management. Given their wide use and overall successful outcomes, it becomes increasingly pertinent for clinicians to readily identify their side effects. Their effects can involve multiple organ systems, including hematologic. This review aims to identify and classify the range of hematologic effects associated with individual biologics and kinase inhibitors used for treatment of rheumatologic diseases.

Practical guidance for the diagnosis and management of secondary hypogammaglobulinemia: A Work Group Report of the AAAAI Primary Immunodeficiency and Altered Immune Response Committees

Secondary hypogammaglobulinemia (SHG) is characterized by reduced immunoglobulin levels due to acquired causes of decreased antibody production or increased antibody loss. Clarification regarding whether the hypogammaglobulinemia is secondary or primary is important because this has implications for evaluation and management. Prior receipt of immunosuppressive medications and/or presence of conditions associated with SHG development, including protein loss syndromes, are histories that raise suspicion for SHG. In patients with these histories, a thorough investigation of potential etiologies of SHG reviewed in this report is needed to devise an effective treatment plan focused on removal of iatrogenic causes (eg, discontinuation of an offending drug) or treatment of the underlying condition (eg, management of nephrotic syndrome). When iatrogenic causes cannot be removed or underlying conditions cannot be reversed, therapeutic options are not clearly delineated but include heightened monitoring for clinical infections, supportive antimicrobials, and in some cases, immunoglobulin replacement therapy. This report serves to summarize the existing literature regarding immunosuppressive medications and populations (autoimmune, neurologic, hematologic/oncologic, pulmonary, posttransplant, protein-losing) associated with SHG and highlights key areas for future investigation.

Hypogammaglobulinemia, infections and COVID-19 in people with multiple sclerosis treated with ocrelizumab

Objective

To determine the influence of immunoglobulins (Ig) level on the rate of infections in people with multiple sclerosis (pwMS) treated with ocrelizumab.

Methods

We enrolled 109 consecutive pwMS treated with ocrelizumab with a mean follow-up of 2.69±0.56 (1.36-4.27) years. We have retrospectively searched our electronic database and the following information was collected: age, sex, MS characteristics, number of ocrelizumab cycles, infections, duration of the infection, hospitalization due to infection, treatment of the infection, and COVID-19 characteristics. Ig levels were measured within 14 days before each ocrelizumab infusion.

Results

Number of pwMS with values of IgM and IgG below lower level of normal at baseline was 3 (2.8%) and 2 (2.8%), respectively; and before 6^th cycle of ocrelizumab 5 (13.5%) and 5 (13.5%), respectively. Levels of IgM were steadily decreasing over time, while levels of IgG started to show statistically significant drop only after 5^th cycle of ocrelizumab. 58.7% pwMS experienced infection during treatment, with a median number of infections per pwMS being 1, range 0-4. Female sex increased the risk of any infection (HR 2.561, 95%CI 1.382-4.774, p=0.003). Higher age and smaller drop in IgM before 3^rd ocrelizumab cycle increased the risk for infection requiring hospitalization (HR 1.086, 95%CI 1.018-1.159, p=0.013 and HR 9.216, 95%CI 1.124-75.558, p=0.039, respectively). Longer disease duration increased the risk for COVID-19 (HR 1.075, 95%CI 1.002-1.154, p=0.045).

Conclusion

The present findings broaden limited real-world data on infection and COVID-19 risk in pwMS treated with ocrelizumab.

Intensive Safety Monitoring of Rituximab (Biosimilar Novex® and the Innovator) in Pediatric Patients With Complex Diseases

Although rituximab is widely used off-label for complex pediatric diseases, safety reports are limited. We aimed to report evidence of its use in clinical practice, to describe the incidence of adverse drug reactions (ADR) to rituximab biosimilar Novex^® and innovator, and to identify risk factors for the development of ADR in a real-life follow-up cohort of pediatric patients with complex diseases. We conducted a prospective, longitudinal, observational, single-centre study in patients that received rituximab for any complex disease, and as part of an intensive pharmacovigilance program. Demographic, pharmacological, clinical, and drug-related data were collected for all patients. ADR-free survival, including infusion-related reactions (IRR) and delayed ADR (dADR), was estimated using Kaplan-Meier curves. Risk factors were evaluated by multivariable Cox regression models. In total, 77 patients (<19 y.o.) received 187 infusions of rituximab Novex^® (n = 155) or innovator rituximab (n = 32) for neurologic (Neu), immune-hematologic-rheumatic (IHR), oncologic (O) diseases, and hematopoietic stem-cell transplantation (HSCT) or solid-organ transplantation (SOT). We recorded 29 IRR and 58 dADR that occurred in 27 (35.1%) and 29 (37.7%) patients, respectively. The respiratory tract was the most affected during IRR (29.6%) and hypogammaglobulinemia (37.9 %) was the most frequent dADR. First versus subsequent infusions (HR 5.4, CI95% 2.4-12.1, p<0.05), sex (boys vs. girls, HR 0.3, CI95% 0.1-0.8, and p<0.05), and diagnosis (Neu-IHR diseases vs. O-HSCT-SOT, HR 2.3, CI95% 1.02-5.4, and p < 0.05) were significantly associated with the development of IRR. For dADR, risk factors were diagnosis (Neu-IHR diseases vs. O-HSCT-SOT, HR 0.4, CI95% 0.2-0.9, and p < 0.05) and cumulative body surface area-normalized dosage (HR 1.0003, CI95% 1.0001-1.0006, and p < 0.05). The present is the largest real-world safety assessment of rituximab in Latin-American children with complex diseases supporting its use based on the overall acceptable safety. Identification of risk factors may contribute to optimization of off-label rituximab treatment in pediatrics.

Immunogenicity of Rituximab biosimilar GP2013 in chronic inflammatory rheumatic disorders in daily clinical practice

OBJECTIVE

To study in daily practice the risk of immunogenicity of patients treated with the biosimilar rituximab (RTX) GP2013 used for chronic inflammatory rheumatic disorders.

METHODS

A prospective monocentric routine care study was carried out between September 2018 and May 2021, including consecutive patients treated with the biosimilar RTX GP2013. Biosamples were taken before each infusion to quantify anti-RTX antibodies (ADAbs) and serum RTX trough levels by ELISA (Lisa Tracker Duo Rituximab, LTR005, Theradiag).

RESULTS

168 GP2013-treated patients were included (129 who switched from originator RTX and 39 originator RTX naïve). The analysis of 602 samples identified 15 patients (8%) with positive ADAbs including 6 and 9 with transient and persistent ADAbs, respectively. The switch from originator RTX to GP2013 did not increase the risk of immunogenicity, with an incidence rate of 0.8 for 100 patient years. The frequency of persistent ADAs was higher in non-RA patients (5/56, 9% vs. 4/112, 3.5%). Patients with positive persistent ADAbs were more frequently non-caucasian (7/9, 78%, vs. 56/159, 35%, p<0.01) and all had detectable circulating B cells (vs. 40% in ADAb-negative patients, P<0.001). ADAb positivity was not associated with disease activity or RTX discontinuation but patients with ADAb titers >100 ng/mL experienced reduced treatment efficacy or severe infusion-related reaction.

CONCLUSION

Within the study duration, the immunogenicity of GP2013 is a rare event affecting the pharmacodynamics of RTX. Although development of ADAbs had no impact on treatment discontinuation, possible harmful consequences may be observed in patients with high antibody levels.

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.

Case Report: Persistent Hypogammaglobulinemia More Than 10 Years After Rituximab Given Post-HSCT

Rituximab (RTX) is an anti-CD20 monoclonal antibody that targets B cells-from the immature pre-B-cell stage in the bone marrow to mature circulating B cells-while preserving stem cells and plasma cells. It is used to treat autoimmune diseases, hematological malignancies, or complications after hematopoietic stem cell transplantation (HSCT). Its safety profile is acceptable; however, a subset of patients can develop persistent hypogammaglobulinemia and associated severe complications, especially in pediatric populations. We report the unrelated cases of two young men aged 17 and 22, presenting with persistent hypogammaglobulinemia more than 7 and 10 years after treatment with RTX, respectively, and administered after HSCT for hemolytic anemia and Epstein-Barr virus reactivation, respectively. Both patients' immunological workups showed low levels of total immunoglobulin, vaccine antibodies, and class switched-memory B cells but an increase in naive B cells, which can also be observed in primary immunodeficiencies such as those making up common variable immunodeficiency. Whole exome sequencing for one of the patients failed to detect a pathogenic variant causing a Mendelian immunological disorder. Annual assessments involving interruption of immunoglobulin replacement therapy each summer failed to demonstrate the recovery of endogenous immunoglobulin production or normal numbers of class switched-memory B cells 7 and 10 years after the patients' respective treatments with RTX. Although the factors that may lead to prolonged hypogammaglobulinemia after rituximab treatment (if necessary) remain unclear, a comprehensive immunological workup before treatment and long-term follow-up are mandatory to assess long-term complications, especially in children.

Immunosuppression in Rheumatologic and Auto-immune Disease

Many rheumatologic diseases are thought to originate in dysregulation of the immune system; lupus nephritis, for example, involves humoral immunity, while autoinflammatory diseases such as familial Mediterranean fever are caused by defects in innate immunity. Of note, this dysregulation may involve both upregulation of immune system components and aspects of immunodeficiency. Treatment of rheumatologic diseases thus requires a familiarity with a variety of immunosuppressive medications and their effects on immune system function.In many rheumatologic conditions, due to an incompletely elucidated mechanism of disease, immunosuppression is relatively broad in contrast to agents used, for example, in treatment of transplant rejection. Multiple immunosuppressive drugs may also be used in succession or in combination. As such, an understanding of the mechanisms and targets of immunosuppressive drugs is essential to appreciating their utility and potential adverse effects. Because of the overlap between therapies used in rheumatologic as well as other inflammatory disorders, some of these medications are discussed in other disease processes (e.g., Immunosuppression for inflammatory bowel disease) or in greater detail in other chapters of this textbook (corticosteroids, mTOR inhibitors, antiproliferative agents).

Tocilizumab for the treatment of immune-related adverse events: a systematic literature review and a multicentre case series

OBJECTIVE

Research is moving towards a more personalized management of immune-related adverse events (irAEs) due to immune checkpoint inhibitors (ICI). Our objective was to evaluate the efficacy and safety of tocilizumab in the treatment of these clinical manifestations.

METHODS

A systematic literature review was performed to retrieve data about the use of tocilizumab in the treatment of irAEs. Additionally, data from cancer patients referred to our Immune-related Adverse Event Clinic and treated with tocilizumab were collected.

RESULTS

Our literature review identified 20 articles and 11 meeting abstracts. Data about 91 cancer patients who received tocilizumab for the treatment of irAEs were collected. In 85% of cases, this therapy was associated with clinical benefit and no case of disease progression was reported. ICI therapy was continued following irAE onset and biologic therapy initiation in only three patients. Five patients developed irAEs upon ICI initiation and were subsequently treated with tocilizumab at our Centre. At a median follow-up of eight months, tocilizumab was safely continued along with ICI in three out of five patients, and an adequate control of irAE was obtained in all cases. No significant adverse reactions to tocilizumab were reported. Only one patient experienced a disease progression 18 months after ICI discontinuation.

CONCLUSION

Both our systematic literature review and case series highlight the efficacy and safety of tocilizumab in the treatment of irAEs. Furthermore, they both support the possibility of a combined approach with tocilizumab and ICI, to guarantee an effective irAEs management without losing the oncologic response.

Long-term Safety of Rituximab in Primary Sjögren Syndrome: The Experience of a Single Center

OBJECTIVE

This work aims to evaluate the long-term safety of rituximab (RTX) in primary Sjögren syndrome (pSS) and to determine the safety and the efficacy of long-term treatment with B cell depleting therapy in pSS patients with active systemic disease.

METHODS

A historical cohort study, enrolling 35 patients with pSS treated with RTX between 2008 and 2019 in a single rheumatologic unit, was performed. When patients experienced adverse events, the treatment was suspended and patients' data were recorded.

RESULTS

The included patients were mainly female (91%), with a mean age of 54 years. During the time of observation, 13 patients (37.1%) suspended RTX treatment (10 cases per 100 patient-years, 95% CI 0.06-0.17). Baseline demographics, disease characteristics, European Alliance of Associations for Rheumatology (EULAR) Sjögren's Syndrome Disease Activity Index (ESSDAI) values, and treatment were comparable across RTX-suspended and nonsuspended groups. Patients exposed to RTX had been followed for 35.82 ± 32.56 months, and the time of observation varied from 6 to 96 months. All the patients except one experienced a significant and persisting meaningful improvement of their ESSDAI (≥ 3 points) during the long-term follow-up. For the duration of the follow-up, 13 (37%) patients discontinued RTX treatment. Four out of 13 (30.8%) discontinued the treatment after the first administration due to infusion-related reactions. During subsequent RTX courses, the main cause of withdrawal was hypogammaglobulinemia onset (7 patients). In 2 patients, hypogammaglobulinemia was associated with severe infections.

CONCLUSION

Long-term RTX administration was shown to be a safe, well tolerated, and effective treatment in patients with active systemic disease, significantly reducing ESSDAI and controlling disease activity.

Hypogammaglobulinemia after rituximab for rheumatoid arthritis is not rare and is related with good response: 13 years real-life experience

OBJECTIVES

Rituximab (RTX) use in the treatment of RA can be complicated by decrease in IgG, IgM or IgA levels (hypogammaglobulinemia-HGG). The aim of this study was to define the frequency of HGG in RA patients treated with RTX and to identify associations between its occurrence and patients' characteristics, disease outcomes and serious infections rate.

METHODS

RA patients treated with RTX in two rheumatology centers from January 2007 to January 2020 were retrospectively examined. Demographical, clinical and laboratory parameters were recorded at baseline and at last visit.

RESULTS

Eighty-three patients (84.3% females) with a mean age of 63.2 years were enrolled. They had baseline DAS28(CRP) of 5.2  (1.1) and received a median (range) of 8 (2-20) RTX cycles. A total of 43.4%, 24.1% and 31.3% developed 'any HGG', 'low IgG' and 'low IgM', respectively. Lower baseline IgG and IgM levels were predictors of 'low IgG' and 'low IgM' occurrence, respectively. Patients who developed 'low IgM' exhibited lower DAS28(CRP) and increased rates of remission and low disease activity compared with those with normal IgM levels. Patients who maintained normal IgG were receiving methotrexate more frequently. No differences were observed in serious infections rate among subgroups.

CONCLUSION

HGG occurred in 43% of RTX-treated patients. Patients who developed low IgG or low IgM had lower baseline levels than those who did not. Concomitant DMARD and corticosteroid therapy was not associated with HGG. Low IgM, but not low IgG, development was associated with better disease outcomes. HGG was not associated with an increased incidence of serious infections.

Rituximab Associated Hypogammaglobulinemia in Autoimmune Disease

Objective

To evaluate the characteristics of patients with autoimmune disease with hypogammaglobulinemia following rituximab (RTX) and describe their long-term outcomes, including those who commenced immunoglobulin replacement therapy.

Methods

Patients received RTX for autoimmune disease between 2003 and 2012 with immunoglobulin G (IgG) <7g/L were included in this retrospective series. Hypogammaglobulinemia was classified by nadir IgG subgroups of 5 to <7g/L (mild), 3 to <5g/L (moderate) and <3g/L (severe). Characteristics of patients were compared across subgroups and examined for factors associated with greater likelihood of long term hypogammaglobulinemia or immunoglobulin replacement.

Results

142 patients were included; 101 (71%) had anti-neutrophil cytoplasm antibody (ANCA) associated vasculitis (AAV), 18 (13%) systemic lupus erythematosus (SLE) and 23 (16%) other conditions. Mean follow-up was 97.2 months from first RTX. Hypogammaglobulinemia continued to be identified during long-term follow-up. Median time to IgG <5g/L was 22.5 months. Greater likelihood of moderate hypogammaglobulinemia (IgG <5g/L) and/or use of immunoglobulin replacement therapy at 60 months was observed in patients with prior cyclophosphamide exposure (odds ratio (OR) 3.60 [95% confidence interval (CI) 1.03 – 12.53], glucocorticoid use at 12 months [OR 7.48 (95% CI 1.28 – 43.55], lower nadir IgG within 12 months of RTX commencement [OR 0.68 (95% CI 0.51 – 0.90)] and female sex [OR 8.57 (95% CI 2.07 – 35.43)]. Immunoglobulin replacement was commenced in 29/142 (20%) and associated with reduction in infection rates, but not severe infection rates.

Conclusion

Hypogammaglobulinemia continues to occur in long-term follow-up post-RTX. In patients with recurrent infections, immunoglobulin replacement reduced rates of non-severe infections.

Rituximab-associated hypogammaglobulinemia in autoimmune rheumatic diseases: a single-center retrospective cohort study

B-cell targeted therapies, such as rituximab (RTX), are used widely in autoimmune rheumatic diseases (AIRD). RTX can cause hypogammaglobulinemia and predispose patients to infections. Herein, we asked whether the underlying diagnosis influences the risk for hypogammaglobulinemia in patients treated with RTX. All patients who received RTX infusions and carried a diagnosis of rheumatoid arthritis (RA), ANCA-associated vasculitis (AAV), or connective tissue disease (CTD) were included in this single-center retrospective cohort study. We used STATA® for analysis: Chi-square test was used for comparing categorical variables. Based on distribution, continuous variables were compared using the t test/ANOVA or the Wilcoxon/Kruskal–Wallis tests. Of the 163 patients who received RTX for an AIRD, 60 with pre- and post- RTX immunoglobulins were analyzed. A higher incidence of post-treatment hypogammaglobulinemia was seen in AAV (45%) compared to RA (22%) and CTD (9.1%) groups (p = 0.03). Glucocorticoid exposure of 10 mg or more was identified as a significant risk factor for hypogammaglobulinemia. Finally, we observed a higher number of clinically significant infections per person in the AAV group than in the RA and CTD groups. We observed an increased incidence of hypogammaglobulinemia in the RTX-treated AAV group, with almost half of patients developing post-RTX hypogammaglobulinemia. The rate of infections per person was highest in the AAV group. Screening immunoglobulins were not consistently measured pre- and post-RTX. Results highlight a need for increased awareness of the role of immunoglobulin measurement before maintenance doses of RTX, especially in patients with AAV and steroid exposure.

Immunoglobulin levels in systemic lupus erythematosus: A narrative review

Immunoglobulins play a fundamental role in the protection of the human body against internal and external threats. They also contribute to the immune system homeostasis and maintenance of self-tolerance. Hypogammaglobulinemia is occasionally encountered in routine clinical practice by rheumatologists. Low levels of immunoglobulins can occur as primary or secondary issues and may predispose patients to various forms of infection. However, the impact of the low immunoglobulin level abnormality varies with the underlying condition. In this narrative review, we shed light on the overall types and functions of immunoglobulins for clinicians. We discuss important principles of immunoglobulin measurements. We then consider the primary and secondary causes of low immunoglobulins with a special focus on hypogammaglobulinemia in patients with systemic lupus erythematosus (SLE).

Rituximab-Induced Hypogammaglobulinemia and Infections in AQP4 and MOG Antibody-Associated Diseases

Objective

To determine the potential association between infections and rituximab (RTX)-induced hypogammaglobulinemia among patients with CNS inflammatory diseases.

Methods

We included in a prospective observational study all consecutive adults with aquaporin 4 (AQP4) or myelin oligodendrocyte glycoprotein (MOG) antibody–positive disorders treated with RTX. Dosing schedule was adapted to memory B-cell measurement.

Results

We included 48 patients (mean age 47 [SD: 14] years; 77% females; 31 AQP4 positive and 17 MOG positive). The median follow-up was 3.6 years (range: 0.9–8.1 years). The median number of RTX infusions was 8 (range: 2–14). The median dosing interval was 6 months (range: 1.7–13.7 months). Sixty-seven symptomatic infections (SIs) were observed in 26 of 48 (54%) patients, including 13 severe infections in 9 (19%). Urinary and lower respiratory tract infections were the most frequent, representing 42% and 21% of SI. At RTX onset, the immunoglobulin G (IgG) level was abnormal in 3 of 48 (6%) patients. After RTX, 15 (31%), 11 (23%), 3 (6%), and 0 of 48 patients showed sustained IgG level <7, <6, <4, and <2 g/L, respectively. On multivariate Cox proportional hazards analysis, the main variables explaining the risk of SI were the presence of urinary tract dysfunction (hazard ratio [HR] = 34, 95% CI 4–262, p < 0.001), the dosing intervals (HR = 0.98, 95% CI 0.97–0.99, p < 0.001), and the interaction between IgG level and urinary tract dysfunction (HR = 0.67, 95% CI 0.53–0.85, p < 0.005). IgG level <6 g/L during RTX was associated with male sex (HR = 4, 95% CI 1.4–11.4, p < 0.01) and previous immunosuppression (HR = 3.4, 95% CI 1.2–10, p < 0.05).

Conclusions

RTX used as maintenance therapy in CNS inflammatory diseases is frequently associated with reduced IgG level and increases the infection risk of the most vulnerable patients.

A comparative study of tolerability and effects on immunoglobulin levels and CD19 cell counts with ocrelizumab vs low dose of rituximab in multiple sclerosis

Background

Rituximab (RTX) and ocrelizumab (OCR) are two anti-CD20 biologics used in MS; however, comparisons on safety and efficacy are rare.

Objective

To compare treatment outcomes over the first year with RTX and OCR.

Methods

Retrospective cohort study comprising MS patients initiating RTX at the Karolinska University Hospital (Sweden; n = 311) and OCR at Rocky Mountain MS Clinic (Utah, USA; n = 161), respectively.

Results

Levels of immunoglobulin G measured in blood dropped 0.16 g/L (95% confidence interval 0.01 to 0.31) with each OCR infusion, but remained stable with RTX. In contrast, levels of immunoglobulin M decreased to a similar extent with both drugs. Ten and 15% of patients discontinued treatment with RTX and OCR, respectively (n.s), however, adverse events leading to treatment discontinuation were more common with OCR (6.8% vs 2.6%; p = 0.026). Only 3.1 and 1.6% discontinued OCR and RTX, respectively, due to lack of effect (n.s). The degree of B cell depletion was superior with OCR.

Conclusion

Overall, differences between the two treatments were small. Although the study design precludes robust conclusions regarding the risk-benefit with the studied therapies, our findings indicate that the tolerability and safety with RTX is not inferior to OCR.

High frequency of variants in genes associated with primary immunodeficiencies in patients with rheumatic diseases with secondary hypogammaglobulinaemia

OBJECTIVES

Treatment of rheumatic diseases requires immunomodulatory agents which can compromise antibody production. However, even in case of agents directly targeting B cells, a minority of patients develop hypogammaglobulinaemia, suggesting a genetic predisposition, which has not been investigated so far. The phenotypic overlap between primary immunodeficiency disorders (PIDs) and rheumatic diseases suggests a shared genetic basis, especially in case of patients with rheumatic diseases with hypogammaglobulinaemia.

METHODS

1008 patients with rheumatic diseases visiting the outpatient clinics of the Hannover University Hospital were screened for hypogammaglobulinaemia. Those with persistent hypogammaglobulinaemia and an equal number of patients without it underwent targeted next-generation sequencing, searching for variations in genes linked with hypogammaglobulinaemia in the context of PIDs.

RESULTS

We identified 33 predicted pathogenic variants in 30/64 (46.9%) patients with persistent secondary hypogammaglobulinaemia. All 33 variants were monoallelic and 10 of them in 10/64 (15.6%) patients were found in genes associated with autosomal dominant PIDs. 2/64 (3.1%) patients harboured variants which were previously reported to cause PIDs. In the group without hypogammaglobulinaemia we identified seven monoallelic variants in 7/64 (10.9%), including a variant in a gene associated with an autosomal dominant PID.

CONCLUSIONS

Approximately half of patients with persistent secondary hypogammaglobulinaemia harboured at least a variant in a PID gene. Despite the fact that previous immunomodulatory treatment is an exclusion criterion in the diagnosis of PIDs, we identified genetic variants that can account for PID in patients with clear rheumatic phenotypes who developed hypogammaglobulinaemia after the introduction of immunomodulatory treatment. Our data suggest the common genetic causes of primary and secondary hypogammaglobulinaemia.

Infectious complications of rheumatoid arthritis and psoriatic arthritis during targeted and biological therapies: a viewpoint in 2020

Biological therapies have improved the outcomes of several major inflammatory, autoimmune and also neoplastic disorders. Those directed towards cytokines or other soluble mediators, cell-surface molecules or receptors or various components of intracellular signalling pathways may be associated with the occurrence of infections whose diversity depends on the particular immune target. In this context and following a keynote lecture given by one of us at the European League Against Rheumatism meeting on June 2018, a multidisciplinary group of experts deeply involved in the use of targeted and biological therapies in rheumatoid and psoriatic arthritis decided to summarise their recent vision of the immunological basis and epidemiology of infections occurring during targeted and biological therapies, and provide useful indications for their management and prevention.

Rituximab and immune thrombocytopenia in adults: The state of knowledge 20 years later

Rituximab has been used for immune thrombocytopenia (ITP) for almost 20 years and is now considered a valid off-label second-line treatment. About 60% to 70% of patients with ITP show initial response to rituximab, but in half of these patients, the disease will eventually relapse. Therefore, in 30% of patients with persistent or chronic ITP, one course of rituximab at 375 mg/m²/week for 4 weeks or 2 fixed 1000-mg rituximab infusions allows for a sustained response rate at 5 years. Unfortunately, to date, no robust predictor of long-term sustained response has been found to assist the physician in deciding to treat with rituximab on an individual basis, and the choice of rituximab or another second-line treatment must be individualized and shared with the patient. Retreatment with rituximab has been found efficient, with a similar or higher magnitude and duration of response in most patients. Rituximab is usually well tolerated, with mainly mild and easily manageable infusion-related adverse events. Severe infections are uncommon, including in the long-term, and occur in patients with at least another contributing factor in more than two thirds. Several issues remain to be resolved. Indeed, head-to-head comparisons with other and new treatments in ITP and robust predictors of long-term response are urgently needed to better determine the position of rituximab in the therapeutic armamentarium for adult ITP. Additionally, the place of combination therapies, maintenance therapy with rituximab and rituximab in newly-diagnosed ITP deserve additional studies.

[Biotherapies in elderly patients]

The ageing of the population leads health professionals to question the tolerance and the effectiveness of the different biotherapies used in autoimmune diseases. Due to the exponential increase of biotherapies and their indications, several studies have been carried out to evaluate their impact on elderly patients suffering from autoimmune disease. However, these studies are still too few to take into account all the different specificities of elderly patients and their comorbidities; prescribers are therefore hesitant with their introduction after 75 years or even 65. More than the age of patients, it is necessary to evaluate the comorbidities before introducing this kind of treatments. Every biotherapy has different indications and contraindications, which must be known to adapt each treatment to each patient. This focus aims to remind of the adaptations and contraindications of the different biological disease-modifying anti-rheumatic drugs for geriatric population, and improve their uses since the treatments for these patients are sometimes not enough. Here we resume the methods allowing supervisors to identify errors of clinical reasoning in medical students and interns and we explain remediation techniques adapted to the types of error identified. Access to short illustrative videos of a MOOC (Massive Open On line Course) devoted to the supervision of clinical reasoning constitutes practical help for supervisors who are not expert in the complexity of medical pedagogy at the bedside.

Outcome of autoimmune cytopenia after hematopoietic cell transplantation in primary immunodeficiency

BACKGROUND

Post hematopoietic cell transplantation (HCT) autoimmune cytopenia (AIC) is a potentially life-threatening complication, but studies focusing on large cohorts of patients transplanted for primary immunodeficiency are lacking.

OBJECTIVES

This study sought to determine the incidence, risk factors, and outcomes of post-HCT AIC and B-lymphocyte function following rituximab.

METHODS

We retrospectively studied 502 children with primary immunodeficiency who were transplanted at our center between 1987 and 2018.

RESULTS

Thirty-six patients (9%) developed post-HCT AIC, with a median onset of 6.5 months post-HCT. On univariate analysis, pre-HCT AIC, mismatched donor, alemtuzumab, anti-thymocyte antiglobulin, and acute and chronic graft versus host disease were significantly associated with post-HCT AIC. After multivariate analysis, alemtuzumab (subdistribution hazard ratio, 9.0; 95% CI, 1.50-54.0; P = .02) was independently associated with post-HCT AIC. Corticosteroid and high-dose intravenous immunoglobulin achieved remission in 50% (n = 18), additional rituximab led to remission in 25% (n = 9), and the remaining 25% were treated with a combination of various modalities including sirolimus (n = 5), bortezomib (n = 3), mycophenolate mofetil (n = 2), splenectomy (n = 2), and second HCT (n = 3). The mortality of post-HCT AIC reduced from 25% (4 of 16) prior to 2011 to 5% (1 of 20) after 2011. The median follow-up of 5.8 years (range, 0.4 to 29.1 years) showed that 26 of 30 survivors (87%) were in complete remission, and 4 were in remission with ongoing sirolimus and low-dose steroids. Of the 17 who received rituximab, 7 had B-lymphocyte recovery, 5 had persistent low B-lymphocyte count and remained on intravenous immunoglobulin replacement, 2 had second HCT, and 3 died.

CONCLUSIONS

The frequency of post HCT AIC in our cohort was 9%, and the most significant risk factors for its occurrence were the presence of graft versus host disease and the use of alemtuzumab.

Infections Related to Biologics: Agents Targeting B Cells

B cells are an essential component of the adaptive immune system. Since the late 1990s biologic drugs targeting B cells have been used to treat not only lymphoproliferative diseases of B-cell lineage cells but also autoimmune diseases, in particular, those associated with autoantibody production. Although some of these agents are relatively safe, they have been associated with serious infections including opportunistic infections. To what extent the infectious complications reported are directly related to the use of the B-cell targeting agent or to previous and/or concomitant immunosuppressive therapies and/or the specific disease being treated is often difficult to ascertain.

Secondary Hypogammaglobulinemia: An Increasingly Recognized Complication of Treatment with Immunomodulators and After Solid Organ Transplantation

Secondary hypogammaglobulinemia is a common development in patients treated with immunomodulatory agents for autoimmune, connective tissue, and malignant diseases. It has been observed in the medical management of patients undergoing hematopoietic stem cell and solid organ transplantation. Some patients have preexisting immunodeficiency associated with these illnesses; immunosuppressive treatment magnifies their immune defect. This article reviews immunosuppressive medications, including biological treatments that cause secondary hypogammaglobulinemia. It summarizes risk factors for rituximab-induced hypogammaglobulinemia, such as preexisting low immunoglobulin G levels, CD19 levels, host factors, and additive effect of all immunomodulatory drugs used. The evaluation and management of secondary hypogammaglobulinemia are discussed.

Long-term safety and efficacy of rituximab in 248 adults with immune thrombocytopenia: Results at 5 years from the French prospective registry ITP-ritux

Rituximab is a second-line option in adults with immune thrombocytopenia (ITP), but the estimated 5-year response rate, only based on pooled retrospective data, is about 20%, and no studies have focused on long-term safety. We conducted a prospective multicenter registry of 248 adults with ITP treated with rituximab with 5 years of follow-up to assess its long-term safety and efficacy. The median follow-up was 68.4 [53.7-78.5] months. The incidence of severe infections was only 2/100 patient-years. Profound hypogammaglobulinemia (<5 g/L) developed in five patients at 15 to 31 months after the last rituximab infusion. In total, 25 patients died at a median age of 80 [69.5-83.9] years, corresponding to a mortality rate of 2.3/100 patient-years. Only three deaths related to infection that occurred 12 to 14 months after rituximab infusions could be due in part to rituximab. At 60 months of follow-up, 73 (29.4%) patients had a sustained response. On univariate and multivariate analysis, the only factor significantly associated with sustained response was a previous transient response to corticosteroids (P = .022). Overall, 24 patients with an initial response and then relapse received retreatment with rituximab, which gave a response in 92%, with a higher duration of response in 54%. As a result of its safety profile and its sustained response rate, rituximab remains an important option in the current therapeutic armamentarium for adult ITP. Retreatment could be an effective and safe option.

Predicting Severe Infection and Effects of Hypogammaglobulinemia During Therapy With Rituximab in Rheumatic and Musculoskeletal Diseases

OBJECTIVE

To evaluate predictors of serious infection events (SIEs) during rituximab (RTX) therapy and effects of hypogammaglobulinemia on SIE rates, and humoral response and its persistence after discontinuation of RTX in the treatment of rheumatic and musculoskeletal diseases (RMDs).

METHODS

A retrospective longitudinal study of 700 RMD patients treated with RTX in a single center was conducted. Immunoglobulin levels were measured at baseline and at 4-6 months after each treatment cycle. Baseline predictors of SIEs were assessed using multivariable logistic regression; for RTX cycles 2-4, a mixed-effects logistic regression model was used.

RESULTS

A total of 507 patients (72%) had rheumatoid arthritis, 94 (13%) had systemic lupus erythematosus, 49 (7%) had antineutrophil cytoplasmic antibody-associated vasculitis, and 50 (7%) had other RMDs. The number of SIEs recorded was 281 in 176 patients (9.8 per 100 person-years). Predictors of SIEs included non-RTX-specific comorbidities (previous history of SIE, cancer, chronic lung disease, diabetes mellitus, and heart failure), higher corticosteroid dose, and RTX-specific factors, including low IgG (<6 gm/liter) both at baseline and during treatment, RTX-associated neutropenia, higher IgM, and longer time to RTX re-treatment, but not B cell count or depletion status. Of 110 patients with low IgG, SIE rates were higher in those with low IgG at baseline (16.4 per 100 person-years) and in those who acquired low IgG during or after RTX treatment (21.3 per 100 person-years) versus those with normal IgG (9.7 per 100 person-years). Five of 8 patients (63%) had impaired humoral response to pneumococcus and hemophilus following vaccination challenge, and only 4 of 11 patients (36%) had IgG normalized after switching biologic disease-modifying antirheumatic drugs.

CONCLUSION

Immunoglobulin levels should be monitored at baseline and before each RTX cycle to identify patients at risk of SIEs. Individualized risk-benefit assessment should be undertaken in those with lower IgG as this is a consistent SIE predictor and may increase infection profiles when RTX is switched to different therapies.

Iatrogenic antibody deficiency from B-cell targeted therapies in autoimmune rheumatic diseases

B-cell targeted therapies (BCTT) are now widely used in autoimmune rheumatic diseases, including SLE, antineutrophil cytoplasmic antibody-associated vasculitis and rheumatoid arthritis. Early studies suggested that rituximab did not influence serum immunoglobulins. However, subsequently, with increased patient numbers, longer follow-up duration and many patients having received multiple BCTT courses, multiple subsequent studies have identified hypogammaglobulinaemia as a potential side effect. Patients developing hypogammaglobulinaemia appear to fit into two principal categories: the majority who develop transient, often mild reduction in immunoglobulins without increased infection and a much smaller but clinically significant group with a more sustained antibody deficiency, who display increased risk of infection. Monitoring immunoglobulin levels represents an opportunity for the early detection of hypogammaglobulinaemia, and the prevention of avoidable morbidity. In the two major studies, approximately 4%-5% of BCTT-treated patients required immunoglobulin replacement due to recurrent infections in the context of hypogammaglobulinaemia. Despite this, monitoring of immunoglobulins is suboptimal, and there remains a lack of awareness of hypogammaglobulinaemia as an important side effect.