Serum sickness secondary to treatment with the murine-human chimeric antibody IDEC-C2B8 (rituximab)

Development and validation of an automated assay for anti-drug-antibodies in rat serum

The potential immunogenicity of therapeutic human and humanized monoclonal antibodies (mAb) is a significant concern, and so preclinical testing of therapeutic mAbs routinely includes assessment of anti-drug antibody (ADA) induction. Here, we report the development of automated screening and confirmatory bridging ELISAs for the detection of rat antibodies against DH1042, an engineered human mAb for the SARS-CoV-2 receptor-binding domain. The assays were evaluated for specificity, sensitivity, selectivity, absence of a prozone effect, linearity, intra- and inter- assay precision, and robustness, and found to be suitable for purpose. The assays were then used to evaluate anti-DH1042 antibodies in the sera of rats dosed with lipid-nanoparticle (LNP)-encapsulated mRNA encoding DH1042. Rats received two doses of 0.1, 0.4 or 0.6 mg/kg/dose LNP-mRNA 8 days apart. Twenty-one days after the second dose, 50-100% of rats had developed confirmed anti-DH1042 ADA depending on dose level. No animals in the control group developed anti-DH1042 ADA. These assays reflect new applications for a non-specialized laboratory automation platform, and the methodologies and approaches reported here provide a template that can be adapted for the automated detection and confirmation of ADA in preclinical testing of other biologics.

Preclinical risk assessment strategy to mitigate the T-cell dependent immunogenicity of protein biotherapeutics: State of the art, challenges and future perspectives

Protein therapeutics hold a prominent role and have brought significant diversity in efficacious medicinal products. Not just monoclonal antibodies and different antibody formats (pegylated antigen-binding fragments, bispecifics, antibody-drug conjugates, single chain variable fragments, nanobodies, dia-, tria- and tetrabodies), but also purified blood products, growth factors, recombinant cytokines, enzyme replacement factors, fusion proteins are all good instances of therapeutic proteins that have been developed in the past decades and approved for their value in oncology, immune-oncology, and autoimmune diseases discovery programs. Although there was an ingrained belief that fully humanized proteins were expected to have limited immunogenicity, adverse effects associated with immune responses to biological therapies raised some concern in biotech companies. Consequently, drug developers are designing strategies to assess potential immune responses to protein therapeutics during both the preclinical and clinical phases of development. Despite the many factors that can contribute to protein immunogenicity, T cell- (thymus-) dependent (Td) immunogenicity seems to play a crucial role in the development of anti-drug antibodies (ADAs) to biologics. A broad range of methodologies to predict and rationally assess Td immune responses to protein drugs has been developed. This review aims to briefly summarize the preclinical immunogenicity risk assessment strategy to mitigate the risk of potential immunogenic candidates coming towards clinical phases, discussing the advantages and limitations of these technologies, and suggesting a rational approach for assessing and mitigating Td immunogenicity.

Preemptive cyclosporin A in immune-mediated thrombotic thrombocytopenic purpura

Survivors of immune-mediated thrombotic thrombocytopenic purpura (iTTP) are exposed to clinical relapses when a disintegrin and metalloproteinase with thrombospondin type 1 repeats, member 13 (ADAMTS13) activity decreases during follow-up. Although preemptive rituximab usually improves ADAMTS13 activity in this context, 15% of patients experience refractoriness or intolerance to rituximab and require alternative strategies. Here, we addressed whether cyclosporine A (CSA) could improve ADAMTS13 activity and prevent clinical relapses in this context. We treated preemptively with CSA 14 iTTP patients who were unresponsive (n = 11) or intolerant (n = 3) to rituximab. All patients had a severe ADAMTS13 deficiency (activity <20%) and otherwise in clinical remission. ADAMTS13 activity normalized in almost all patients (n = 13, 93%), after a median time of 2.5 months [IQR 1-6] following initiation. Median duration of CSA treatment was 17.5 months [IQR 10-34]. ADAMTS13 activity further declined to undetectable values during follow-up in five patients, but retreatment with rituximab or CSA allowed a recovery in ADAMTS13 activity in three cases. CSA could be stopped durably in two patients, while two others experienced an ADAMTS13 relapse. Severe but reversible side effects requiring cessation of the treatment occurred in two patients. CSA provides high and sustained response rates in patients who are refractory or intolerant to rituximab, with acceptable adverse events.

Rituximab-induced serum sickness in a girl with nephrotic syndrome

Rituximab (RTX) has been used to treat B cell lineage lymphoma/leukemia or autoimmune or autoinflammatory disorders. RTX therapy has been extensively applied to cases of frequently relapsing nephrotic syndrome (FRNS) and steroid-dependent nephrotic syndrome. Rituximab-induced serum sickness (RISS) has been recognized as a rare severe type-3 hypersensitivity reaction in patients treated with RTX. We herein report a 10-year-old girl with RISS in FRNS. She was diagnosed with RISS based on characteristic symptoms, such as a fever, rash, arthritis, or proteinuria, during RTX therapy associated with a high level of human anti-chimeric antibody. Even after recovering from acute symptoms by RISS, she suffered from worsening relapses of nephrotic syndrome. The symptoms of RISS are non-specific, resembling viral infections, autoinflammatory diseases and Kawasaki disease, especially in children. While RISS is a rare complication among patients with nephrotic syndrome, it should be carefully considered as a severe complication in patients being treated with RTX.

Immune- and Non-Immune-Mediated Adverse Effects of Monoclonal Antibody Therapy: A Survey of 110 Approved Antibodies

Identification of new disease-associated biomarkers; specific targeting of such markers by monoclonal antibodies (mAbs); and application of advances in recombinant technology, including the production of humanized and fully human antibodies, has enabled many improved treatment outcomes and successful new biological treatments of some diseases previously neglected or with poor prognoses. Of the 110 mAbs preparations currently approved by the FDA and/or EMA, 46 (including 13 antibody–drug conjugates) recognizing 29 different targets are indicated for the treatment of cancers, and 66, recognizing 48 different targets, are indicated for non-cancer disorders. Despite their specific targeting with the expected accompanying reduced collateral damage for normal healthy non-involved cells, mAbs, may cause types I (anaphylaxis, urticaria), II (e.g., hemolytic anemia, possibly early-onset neutropenia), III (serum sickness, pneumonitis), and IV (Stevens–Johnson syndrome, toxic epidermal necrolysis) hypersensitivities as well as other cutaneous, pulmonary, cardiac, and liver adverse events. MAbs can provoke severe infusion reactions that resemble anaphylaxis and induce a number of systemic, potentially life-threatening syndromes with low frequency. A common feature of most of these syndromes is the release of a cascade of cytokines associated with inflammatory and immunological processes. Epidermal growth factor receptor-targeted antibodies may provoke papulopustular and mucocutaneous eruptions that are not immune-mediated.

Quality of Life, Sleep Quality, Depression, Anxiety, Stress, Eating Habits, and Social Bounds in Nurses during the Coronavirus Disease 2019 Pandemic in Qatar (The PROTECTOR Study): A Cross-Sectional, Comparative Study

There have been numerous concerns regarding the physical and mental health of nurses during the COVID-19 pandemic. Stress, sleep deprivation, anxiety, and depression potentiated nurses’ vulnerability to poor eating habits. Aims and Objectives: The purpose of this study was to explore the differences between nurses’ characteristics with COVID-19 facility designation, and sleep quality, depression, anxiety, stress, eating habits, social bonds, and quality of life. Design: A cross-sectional, comparative study. Methods: An online survey was sent using the corporation’s email to nurses working in three hospitals in Qatar from September to December 2020. One of them is a designated COVID-19 facility. The sleep quality, depression, eating habits, social bonds, and quality of life were measured using The Insomnia Severity Index (ISI), Depression Anxiety and Stress Scale 21 (DASS-21), Emotional Eater Questionnaire (EEQ), Oslo Social Support Scale (OSSS-3), and the World Health Organization Quality of Life (WHOQOL-BREF), respectively. Results: A total of 200 nurses participated in the study (RR: 13.3%). No statistically significant association was found between designated facility (COVID-19 vs. not COVID-19) or nurses’ characteristics and ISI categories (OR 1.15; 95% CI 0.54, 2.44). Nurses working in COVID-19 facilities had increased odds of having higher EEQ categories by 2.62 times (95% CI 1.18, 5.83). Similarly, no statistically significant associations were found between any of the nurses’ characteristics and OSSS-3 categories. On the other hand, no statistically significant associations were found between any of the nurses’ characteristics and QOL domains except for the gender and social relationships’ domain. Conclusion: Overall, the quality of life of nurses in Qatar is on a positive level whether they are assigned to a COVID-19 facility or not. Although no significant difference was found with regard to the sleep quality, stress, anxiety, depression, and eating habits between nurses in a COVID-19 facility and in a non-COVID-19 facility, special interventions to diminish stressors need to be implemented and maintained.

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

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

Serum sickness following rituximab therapy in a patient with pemphigus vulgaris: A case report

Serum sickness, a reaction presenting with a classic triad (fever, rash, myalgia/arthralgia), is considered as a rare adverse event following monoclonal antibodies and specifically following treatment with rituximab. This report describes a case of serum sickness in a newly treated young male patient with rituximab for pemphigus vulgaris.

An innovative method for characterizing neutralizing antibodies against antibody-derived therapeutics

Detection of anti-drug antibodies (ADA) that have a neutralizing capacity is an important aspect of immunogenicity evaluation during development of biotherapeutics, but developing and validating neutralizing antibody (NAb) assays that show direct interference of a biologic function is a challenging and resource-intensive activity. In particular, the need for adequate drug and target tolerance often requires extensive pre-treatment steps that limit assay sensitivity compared with a typical bridging-format assay used to detect binding ADA. Such limitations may complicate data interpretation as a positive ADA followed by a negative NAb result could be due to the presence of non-neutralizing antibodies or could be a false-negative for NAbs due to methodology differences. To address such issues, we developed a novel assay for Nanobodies® and other antibody-derived therapeutics that solely detects ADA directed against the complementarity-determining regions (CDRs) involved in drug-target interactions. This was achieved by creating a "null variant" of the therapeutic drug, which has mutated CDRs rendering it non-functional for target binding but is otherwise identical to the drug compound. Non-CDR-binding antibodies are pre-complexed with the null variant of the Nanobody leaving only CDR-binding ADA with neutralizing potential (ANP) to be detected in this assay, which is called a NAb Epitope Characterization Assay (NECA). Method qualification results confirmed highly comparable assay characteristics (sensitivity, drug tolerance, selectivity and precision) of both the NECA and a validated ADA assay for the same Nanobody. A panel of purified neutralizing and non-neutralizing antibodies as well as non-clinical and clinical samples were used to further substantiate the fit-for-purpose and advantages of this novel assay format to detect ANP. In the clinical case study, a 20 to 40-fold difference in assay sensitivity existed between the validated ADA assay and NAb assay, which complicated data interpretation. Implementation of the NECA allowed unambiguous comparison of the levels of binding ADA and ANP in study samples which enabled us to delineate the true neutralizing capacity of the responses. Depending on the risk of the therapeutic, this method could be a valuable alternative for NAb testing by enabling earlier detection of ADA with neutralizing potential and ensuring adequate immunogenicity risk assessment.

Immunization to rituximab is more frequent in systemic autoimmune diseases than in rheumatoid arthritis: ofatumumab as alternative therapy

OBJECTIVES

The frequency and consequences of anti-drug antibodies to rituximab (RTX-ADA) are not well known in RA and even less in other systemic auto-immune diseases (sAID). We aimed to evaluate the frequency, consequences and predictive factors of RTX-ADA in RA and sAID.

METHODS

All patients presenting with RA or other sAID treated with RTX from 2012 to 2017 in our tertiary reference centre for sAID were retrospectively studied. Patients who were tested for RTX-ADA were identified.

RESULTS

One hundred and ninety-nine patients were treated with RTX (RA: 124, other sAID: 75). Among 62/199 (31.1%) tested for RTX-ADA, 14 were positive: 3/35 RA (8.6%) and 11/27 (40.7%) other sAID, (P = 0.0047). Among the whole RTX-treated populations, the frequency of RTX-ADA was 2.4% and 14.7% (P = 0.0026) in RA and sAID, respectively. Most of the immunized patients had infusion reactions to second or subsequent RTX cycles (11/14) and loss of efficacy (2/14). Predictive factors of immunization were sAID vs RA (78.6% vs 21.4%, P = 0.026, adjusted odds ratio (OR) = 5.35[1.43-54.75]) and African ethnicity (57.1% vs 4.2%, P < 0.001, adjusted OR = 9.25 [5.08-302.12]). Associated immunosuppressive therapy did not protect against immunization. Three patients with pSS immunized against RTX were treated with ofatumumab with complete remission of their disease.

CONCLUSION

Immunization against RTX is more frequent in other sAID than in RA. Testing for RTX-ADA must be performed in patients with infusion reactions or loss of efficacy especially if they are of African origin. Immunized patients might be treated efficiently and safely with ofatumumab. This alternative should be further evaluated for sAID.

Susceptibility to adverse drug reactions

The pharmacological effects of a drug depend on its concentration at the site of action, and therefore on the concentration in blood and on the dose. The relationship between the concentration or dose and the corresponding effect can usually be represented mathematically as a rectangular hyperbola; when effect is plotted against log concentration or log dose, the curve is sigmoidal. Inevitably, the effect size and the doses causing benefit and harm will differ among individuals, since they are biological phenomena: some individuals are more likely than others to suffer harm at any given dose. Some harmful effects can occur at much lower doses than those used in therapeutics; that is, the log dose-response curve for harm lies far to the left of the log dose-response curve for benefit. Those who suffer such reactions are hypersusceptible. When the dose-response curves for harm and therapeutic effect are in the same range, dose cannot separate the harmful effects from the therapeutic effects, and adverse reactions are collateral. Toxic effects occur when harmful doses are above the doses needed for benefit. In this review we consider factors that influence a subject's susceptibility to adverse drug reactions. Determinants of susceptibility include Immunological, Genetic, demographic (Age and Sex), Physiological and Exogenous factors (drug-drug interactions, for example), and Diseases and disorders such as renal failure, giving the mnemonic I GASPED. Some susceptibility factors are discrete (for example, all-or-none) and some are continuous; susceptibility can therefore be discrete or continuous; and the factors can interact to determine a person's overall susceptibility to harm.

Rituximab-induced serum sickness is more frequent in autoimmune diseases as compared to hematological malignancies: A French nationwide study

INTRODUCTION

Rituximab induced serum sickness (RISS) is a rare delayed hypersensitivity reaction. The aim of this study was to describe the epidemiological and clinical characteristics of the RISS cases reported in France.

METHOD

Serum sickness cases involving rituximab were identified from the French PharmacoVigilance Database from 1998 to 2016.

RESULTS

We analyzed 37 cases of RISS. Rituximab was prescribed for an autoimmune disease in 78% of cases. Serum sickness occurred mainly after the first injection (54%) with a median time to onset of 12 days. The most frequent manifestations were rheumatologic symptoms (92%), fever (87%), and skin lesions (78%). The incidence was significantly higher when rituximab was used for autoimmune diseases than for a hematological malignancies. Taking into account the existence of a Systemic Lupus Erythematosus (SLE) as the indication of rituximab or as a comorbidity, the incidence of RISS in patients with SLE was even higher.

DISCUSSION

We report on the largest series of RISS studied to date and confirm that this reaction preferentially occurs in patients with autoimmune disease, especially SLE. This may be due to B-cell lysis, leading to the release of intracellular antigens into the serum and subsequent antigen-antibody complex formation, especially in patients with elevated autoantibody production. This could also explain why RISS often occurred after a single injection.

CONCLUSION

Patients generally recovered from RISS rapidly without obvious benefit from corticosteroid therapy. The risk of recurrence should prompt clinicians to question the use of rituximab after an episode of RISS.

TCPro: an In Silico Risk Assessment Tool for Biotherapeutic Protein Immunogenicity

Most immune responses to biotherapeutic proteins involve the development of anti-drug antibodies (ADAs). New drugs must undergo immunogenicity assessments to identify potential risks at early stages in the drug development process. This immune response is T cell-dependent. Ex vivo assays that monitor T cell proliferation often are used to assess immunogenicity risk. Such assays can be expensive and time-consuming to carry out. Furthermore, T cell proliferation requires presentation of the immunogenic epitope by major histocompatibility complex class II (MHCII) proteins on antigen-presenting cells. The MHC proteins are the most diverse in the human genome. Thus, obtaining cells from subjects that reflect the distribution of the different MHCII proteins in the human population can be challenging. The allelic frequencies of MHCII proteins differ among subpopulations, and understanding the potential immunogenicity risks would thus require generation of datasets for specific subpopulations involving complex subject recruitment. We developed TCPro, a computational tool that predicts the temporal dynamics of T cell counts in common ex vivo assays for drug immunogenicity. Using TCPro, we can test virtual pools of subjects based on MHCII frequencies and estimate immunogenicity risks for different populations. It also provides rapid and inexpensive initial screens for new biotherapeutics and can be used to determine the potential immunogenicity risk of new sequences introduced while bioengineering proteins. We validated TCPro using an experimental immunogenicity dataset, making predictions on the population-based immunogenicity risk of 15 protein-based biotherapeutics. Immunogenicity rankings generated using TCPro are consistent with the reported clinical experience with these therapeutics.

Rituximab treatment for chronic steroid-dependent Henoch-Schonlein purpura: 8 cases and a review of the literature

BACKGROUND

Henoch-Schonlein purpura (HSP) is a small vessel vasculitis that is characterized by non-thrombocytopenic purpura, abdominal pain, arthritis, and glomerulonephritis. Typically, HSP is self-limited requiring only supportive care, but more severe cases may require corticosteroid (CS) treatment. Rarely, a subset of these patients has persistent rash, arthritis, abdominal involvement, or renal disease despite treatment with CS, or has disease recurrence on CS tapering. Refractory HSP has been effectively treated with a variety of CS sparing therapies. For life-threatening refractory HSP, the B cell depleting agent, rituximab (RTX), has been reported as beneficial for children with substantial renal or central nervous system involvement. However, RTX use for children with less severe HSP, but chronic CS dependent disease refractory to CS sparing immunomodulatory agents, has been less well explored. Herein, we describe 8 children treated with RTX for chronic refractory HSP and report a reduction in recurrent hospitalizations and eventual CS discontinuation.

METHODS

This is a retrospective analysis of eight children who were treated with RTX for chronic CS dependent HSP during the years 2006-2014 at a single institution. A chart review of the electronic medical record was performed to determine the presenting symptoms, the type and duration of treatment received, and the number of hospitalizations prior to and after RTX. The number of hospitalizations and oral corticosteroid burden were analyzed using the Wilcoxon signed rank test.

RESULTS

Prior to receiving RTX, seven patients had at least one hospitalization for HSP (median 1.5, range 0-3). Following RTX, only two patients were hospitalized, each a single time for recurrent abdominal pain. The median oral CS burden was 0.345 mg/kg/day before RTX and 0 mg/kg/day at 6 months (p = 0.078), 1 year (p = 0.0625), and 2 years (p = 0.03) following RTX infusion. Seven out of eight children met remission criteria, defined as no active rash, arthritis, nephritis (hematuria and proteinuria), or gastrointestinal distress following RTX. No serious adverse events were noted.

CONCLUSION

Overall, RTX effectively reduced the number of hospital admissions and oral CS burden. RTX also helped most all children achieve clinical remission. RTX appears to be an effective and safe alternative for chronic CS dependent and immunomodulatory refractory childhood HSP.

Serum sickness with refractory nephrotic syndrome following treatment with rituximab

Rituximab (RTX) is effective for treating childhood refractory nephrotic syndrome (NS), such as steroid-dependent (SD), frequently relapsing (FR), and steroid-resistant (SR) NS. While RTX has been proven to be effective in treating SDNS, FRNS, and SRNS, it may cause serum sickness, a rare illness characterized by fever, rash, and arthralgia, 10-14 days after primary antigen exposure or within a few days after secondary antigen exposure, by producing human anti-chimeric antibodies (HACAs). A 17-year-old girl with refractory SDNS treated with RTX and oral cyclosporine A was admitted with fever and arthralgia 10 days after the fifth RTX dose was administered. After RTX was started when she was 14-years-old, SDNS remission was then achieved, and prednisolone was discontinued. Although antibiotics and non-steroidal anti-inflammatory agents were administered, fever and arthralgia continued. After various inspections and clinical course, we considered her as RTX-induced serum sickness (RISS). The patient had an elevated HACA level and was diagnosed with RISS. Fever and arthralgia disappeared 5 days after onset. To the best of our knowledge, this is the first reported case of RISS with NS. Fever, rash, and arthralgia after RTX administration can be the initial symptoms.

Risk of clinical deterioration in patients with lupus nephritis receiving rituximab

Rituximab is a chimeric anti-CD20 monoclonal antibody that is used as an immunosuppressive agent in cyclophosphamide refractory lupus nephritis to induce remission. Although uncontrolled case series suggest efficacy, this is not yet supported by evidence from prospective randomized controlled trials. The objective of this retrospective case series is to report the clinical outcome of seven patients who received rituximab for lupus nephritis in a single centre between 2011 and 2014. One patient had clinical evidence of an uncomplicated response to therapy. A second patient responded well with the first rituximab course, but had transient worsening of renal function and nephrotic syndrome with a second course. The other five patients all had evidence of a clinical deterioration following rituximab. Two had transient worsening of both renal function and nephrotic syndrome, with subsequent evidence of response in one of these. A fifth patient showed evidence of worsening nephrotic syndrome and renal function which then improved but with renal function remaining below the level present before rituximab. A sixth developed rapidly progressive renal failure following rituximab with active nephritis on renal biopsy and required rescue therapy with high dose steroids and cyclophosphamide. A seventh developed a transient worsening of her nephrotic syndrome and an exacerbation of extrarenal symptoms following rituximab. The two patients showing a good response had complete B cell depletion and incomplete depletion may be a factor in the deterioration seen in the other patients. Our experience suggests that rituximab therapy in lupus nephritis is not without risk and patients should be informed of this beforehand. This is particularly important in view of the uncertainty that rituximab will offer a therapeutic benefit.

From the bench to clinical practice: understanding the challenges and uncertainties in immunogenicity testing for biopharmaceuticals

Unlike conventional chemical drugs where immunogenicity typically does not occur, the development of anti-drug antibodies following treatment with biologics has led to concerns about their impact on clinical safety and efficacy. Hence the elucidation of the immunogenicity of biologics is required for drug approval by health regulatory authorities worldwide. Published ADA 'incidence' rates can vary greatly between same-class products and different patient populations. Such differences are due to disparate bioanalytical methods and interpretation approaches, as well as a plethora of product-specific and patient-specific factors that are not fully understood. Therefore, the incidence of ADA and their association with clinical consequences cannot be generalized across products. In this context, the intent of this review article is to discuss the complex nature of ADA and key nuances of the methodologies used for immunogenicity assessments, and to dispel some fallacies and myths.

Anaphylaxis to chemotherapy and monoclonal antibodies

Hypersensitivity reactions are increasingly prevalent, although underrecognized and underreported. Platins induce immunoglobulin E-mediated sensitization; taxenes and some monoclonal antibodies can induce reactions at first exposure. Severe hypersensitivity can preclude first-line therapy. Tryptase level at the time of a reaction is a useful diagnostic tool. Skin testing provides a specific diagnosis. Newer tests are promising diagnostic tools to help identify patients at risk before first exposure. Safe management includes rapid drug desensitization. This review provides information regarding the scope of hypersensitivity and anaphylactic reactions induced by chemotherapy and biological drugs, as well as diagnosis, management, and treatment options.

Rituximab-induced serum sickness: A systematic review

OBJECTIVES

To report a case of rituximab-induced serum sickness (RISS) and perform a systematic review and characterize RISS in autoimmune diseases and hematological malignancies.

METHODS

A comprehensive search of MEDLINE, EMBASE, ACR, and EULAR databases was performed for relevant articles of patients with RISS from inception to September 2014. Statistical analysis of demographic and clinical features was performed using Microsoft EXCEL 2007 and SPSS version 20.0.

RESULTS

In the 33 patients with RISS, the mean age of presentation was 39.1 ± 17.5yr with a female preponderance (n = 23, 76.67%). The majority of cases were associated with an underlying rheumatologic condition (n = 17, 51.5%), most commonly Sjögren's syndrome (n = 8, 44.4%). The classic triad of serum sickness (fever, rash, and arthralgia) was reported in 16 (48.5%) cases. Time from drug exposure to symptom onset was significantly greater with the first doses of rituximab compared to the second dose (mean time 10.00 vs. 4.05d, P = 0.002), and time to resolution was significantly greater for rheumatologic vs. hematological indications (mean time 2.50 vs. 1.00d, P = 0.035). Corticosteroids were the most commonly used treatment (n = 21), with all cases reporting a complete resolution of symptoms in 2.15 ± 1.34d.

CONCLUSION

It is important to recognize RISS clinically, as it may mimic exacerbation of various rheumatologic conditions. Although RISS is typically self-limited, further infusions of rituximab should be avoided, as it may provoke more severe symptoms.

Assessment and reporting of the clinical immunogenicity of therapeutic proteins and peptides-harmonized terminology and tactical recommendations

Immunogenicity is a significant concern for biologic drugs as it can affect both safety and efficacy. To date, the descriptions of product immunogenicity have varied not only due to different degrees of understanding of product immunogenicity at the time of licensing but also due to an evolving lexicon that has generated some confusion in the field. In recent years, there has been growing consensus regarding the data needed to assess product immunogenicity. Harmonization of the strategy for the elucidation of product immunogenicity by drug developers, as well as the use of defined common terminology, can benefit medical practitioners, health regulatory agencies, and ultimately the patients. Clearly, understanding the incidence, kinetics and magnitude of anti-drug antibody (ADA), its neutralizing ability, cross-reactivity with endogenous molecules or other marketed biologic drugs, and related clinical impact may enhance clinical management of patients treated with biologic drugs. To that end, the authors present terms and definitions for describing and analyzing clinical immunogenicity data and suggest approaches to data presentation, emphasizing associations of ADA development with pharmacokinetics, efficacy, and safety that are necessary to assess the clinical relevance of immunogenicity.

Formation, Clearance, Deposition, Pathogenicity, and Identification of Biopharmaceutical-related Immune Complexes

Vascular inflammation, infusion reactions, glomerulopathies, and other potentially adverse effects may be observed in laboratory animals, including monkeys, on toxicity studies of therapeutic monoclonal antibodies and recombinant human protein drugs. Histopathologic and immunohistochemical (IHC) evaluation suggests these effects may be mediated by deposition of immune complexes (ICs) containing the drug, endogenous immunoglobulin, and/or complement components in the affected tissues. ICs may be observed in glomerulus, blood vessels, synovium, lung, liver, skin, eye, choroid plexus, or other tissues or bound to neutrophils, monocytes/macrophages, or platelets. IC deposition may activate complement, kinin, and/or coagulation/fibrinolytic pathways and result in a systemic proinflammatory response. IC clearance is biphasic in humans and monkeys (first from plasma to liver and/or spleen, second from liver or spleen). IC deposition/clearance is affected by IC composition, immunomodulation, and/or complement activation. Case studies are presented from toxicity study monkeys or rats and indicate IHC-IC deposition patterns similar to those predicted by experimental studies of IC-mediated reactions to heterologous protein administration to monkeys and other species. The IHC-staining patterns are consistent with findings associated with generalized and localized IC-associated pathology in humans. However, manifestations of immunogenicity in preclinical species are generally not considered predictive to humans.

Adverse events to monoclonal antibodies used for cancer therapy: Focus on hypersensitivity responses

Fifteen monoclonal antibodies (mAbs) are currently registered and approved for the treatment of a range of different cancers. These mAbs are specific for a limited number of targets (9 in all). Four of these molecules are indeed directed against the B-lymphocyte antigen CD20; 3 against human epidermal growth factor receptor 2 (HER2 or ErbB2), 2 against the epidermal growth factor receptor (EGFR), and 1 each against epithelial cell adhesion molecule (EpCAM), CD30, CD52, vascular endothelial growth factor (VEGF), tumor necrosis factor (ligand) superfamily, member 11 (TNFSF11, best known as RANKL), and cytotoxic T lymphocyte-associated protein 4 (CTLA4). Collectively, the mAbs provoke a wide variety of systemic and cutaneous adverse events including the full range of true hypersensitivities: Type I immediate reactions (anaphylaxis, urticaria); Type II reactions (immune thrombocytopenia, neutopenia, hemolytic anemia); Type III responses (vasculitis, serum sickness; some pulmonary adverse events); and Type IV delayed mucocutaneous reactions as well as infusion reactions/cytokine release syndrome (IRs/CRS), tumor lysis syndrome (TLS), progressive multifocal leukoencephalopathy (PML) and cardiac events. Although the term "hypersensitivity" is widely used, no common definition has been adopted within and between disciplines and the requirement of an immunological basis for a true hypersensitivity reaction is sometimes overlooked. Consequently, some drug-induced adverse events are sometimes incorrectly described as "hypersensitivities" while others that should be described are not.

Monitoring of nonsteroidal immunosuppressive drugs in patients with lung disease and lung transplant recipients: American College of Chest Physicians evidence-based clinical practice guidelines

OBJECTIVES

Immunosuppressive pharmacologic agents prescribed to patients with diffuse interstitial and inflammatory lung disease and lung transplant recipients are associated with potential risks for adverse reactions. Strategies for minimizing such risks include administering these drugs according to established, safe protocols; monitoring to detect manifestations of toxicity; and patient education. Hence, an evidence-based guideline for physicians can improve safety and optimize the likelihood of a successful outcome. To maximize the likelihood that these agents will be used safely, the American College of Chest Physicians established a committee to examine the clinical evidence for the administration and monitoring of immunosuppressive drugs (with the exception of corticosteroids) to identify associated toxicities associated with each drug and appropriate protocols for monitoring these agents.

METHODS

Committee members developed and refined a series of questions about toxicities of immunosuppressives and current approaches to administration and monitoring. A systematic review was carried out by the American College of Chest Physicians. Committee members were supplied with this information and created this evidence-based guideline.

CONCLUSIONS

It is hoped that these guidelines will improve patient safety when immunosuppressive drugs are given to lung transplant recipients and to patients with diffuse interstitial lung disease.

Is thymoglobulin or rituximab the cause of this serum sickness? A case report of serum sickness dilemma and literature review

Serum sickness is an immune-complex-mediated systemic illness that can occur after treatment with monoclonal or polyclonal antibodies such as Rituxan (Rituximab) or antithymocyte globulin (Thymoglobulin), respectively. Since Rituximab is now being used as an adjuvant treatment for acute humoral rejection and its prevalence to cause serum sickness is comparable to Thymoglobulin-associated serum sickness (20% versus 27%), it should be considered a potential cause of serum sickness after rejection treatment. In kidney transplant patients, there are no case reports where patient received both Thymoglobulin and Rituximab before developing serum sickness. We are reporting a patient who developed serum sickness after receiving Thymoglobulin and Rituximab that led us to consider Rituximab as one of the potential causes in this patient's serum sickness. Since diagnosis of serum sickness is clinical, and Rituximab use has expanded into treatment of glomerulonephritis and acute humoral rejection, it should be considered as a potential offender of serum sickness in these patient populations. There are not any evidence-based guidelines or published clinical trials to help guide therapy for antibody-induced serum sickness; however, we successfully treated our case with three doses of Methylprednisone 500 mg intravenously. Further studies are needed to evaluate Rituximab-associated serum sickness in nephrology population to find effective treatment options.

Systemic adverse events following rituximab therapy in patients with Graves' disease

BACKGROUND AND AIM

Rituximab (RTX) therapy has shown promising results in Graves' disease (GD), with or without ophthalmopathy. We examined the occurrence of adverse events in GD patients treated with RTX.

SUBJECTS AND METHODS

Ten patients received RTX and methimazole, while 10 patients received methimazole only. Adverse events were recorded, and the presence of circulating immune complexes (CIC) was measured as IgG, IgM and complement component 3 (C3) depositing on normal monocytes following incubation with patient plasma.

RESULTS

Five patients had benign infusion-related adverse events at first infusion. Two patients developed a serum sickness-like reaction 11 days after the first RTX-infusion. One of these patients developed diarrhea, raised orosomucoid levels, lowgrade inflammation in colonoscopic biopsies, and iridocyclitis 1 yr later. At day 14, the most pronounced immunoglobulin/ C3-adherent to the test monocytes, indicative of CIC, was observed in the presence of plasma from these 2 patients (p=0.003 to p=0.01 vs asymptomatic patients). A 3rd patient had recurrent fever and symmetric polyarthritis from day 38, and colonoscopy-verified ulcerative colitis at day 68. This patient had the 3rd highest increase in Ig deposition on monocytes by day 14. The arthralgias persisted in 2 of the patients, despite glucocorticoid rescue therapy.

CONCLUSIONS

We report articular adverse events in 3 and gastrointestinal symptoms in 2 out of 10 GD patients who received RTX without concurrent immunosupression. The joint symptoms were related to CIC formation.

Characterization of patients with infliximab-induced lupus erythematosus and outcomes after retreatment with a second anti-TNF agent

BACKGROUND

Drug-induced lupus erythematosus (DILE) due to infliximab therapy for inflammatory bowel disease (IBD) is an uncommon occurrence. It remains uncertain whether patients with infliximab-induced DILE could tolerate another antitumor necrosis factor (TNF) agent without recurrent DILE.

METHODS

We reviewed the case records of patients with infliximab-induced DILE diagnosed at our institute and noted details of their clinical and immunological profile at presentation. In addition, case notes of patients who were treated with a second anti-TNF agent were examined for evidence of recurrent DILE.

RESULTS

Thirteen patients with infliximab-induced DILE were identified with a female-to-male ratio of 11:2. Symmetric large joint arthralgias and high titers of antinuclear and antidouble-stranded DNA antibody were noted in all patients. Eight patients were retreated with a second anti-TNF agent (six certolizumab pegol and two adalimumab) of whom two patients (one adalimumab and certolizumab pegol each) developed recurrent DILE following 3 months of therapy with a second anti-TNF agent. One patient discontinued therapy after 2 months despite no recurrence of DILE, due to fear of side effects. Five patients remain well with no recurrence of DILE after a median of 5 months (range 2-6) therapy.

CONCLUSIONS

Rechallenge with a further anti-TNF agent in patients who have developed DILE with infliximab is associated with a low rate of recurrence.

The A, B, Cs of viral hepatitis in the biologic era

PURPOSE OF REVIEW

To evaluate the recent published data on the safety of biological agents, mainly anti-TNFalpha and rituximab, and diagnostic difficulties in the setting of hepatitis B virus (HBV) or hepatitis C virus (HCV) infection and inflammatory arthritides.

RECENT FINDINGS

There are important differences between HBV and HCV carriers; however, clinical observations suggest that hepatotropic virus infection should not preclude the treatment with biologic agents in rheumatic diseases. Retrospective reports on limited series of HBV-infected patients with concomitant chronic arthritis convey that careful patients' clinico-virological assessment, in collaboration with the hepatologist, is necessary before starting immunosuppressive treatments, especially biological agents. Preemptive or combined antiviral treatment is mandatory, mainly in active and inactive HBV carriers. Occult HBV infection should be also carefully evaluated due to potential virus reactivation. In HCV-infected patients without chronic active hepatitis the treatment with biological agents, anti-TNFalpha or rituximab, is generally useful and well tolerated. Preliminary data suggest the possible synergic effects of combined antivirals (alpha-interferon and ribavirin) and anti-TNFalpha (or rituximab) in patients with chronic arthritis and active hepatitis C.

SUMMARY

In all patients with chronic arthritis requiring immunomodulating treatments both HBV and HCV infection along with liver conditions should be evaluated before any therapeutic decisions, including differential diagnosis among virus-related autoimmune disease and simple comorbidity. Patients with HBV infection should be referred to the hepatologist and correctly classified into active, inactive, and occult carriers. Similarly, rheumatic patients with active chronic hepatitis C must be treated with sequential or combined treatment with antiviral and biological agents.

Rituximab may form a complex with IgMkappa mixed cryoglobulin and induce severe systemic reactions in patients with hepatitis C virus-induced vasculitis

OBJECTIVE

To report on 6 cases of hepatitis C virus (HCV)-induced mixed cryoglobulinemia (MC) vasculitis in patients who developed severe systemic reactions after rituximab infusion, and to report the results of the in vitro analysis of the underlying immunologic mechanisms.

METHODS

Twenty-two HCV-infected patients with MC vasculitis received rituximab infusions (a low-dose protocol cycle with 375 mg/m2/week for 4 consecutive weeks in 18 patients and a high-dose protocol cycle with 1,000 mg on days 1 and 15 in 4 patients). Systemic drug reactions following rituximab infusion were recorded and analyzed clinically and immunochemically.

RESULTS

Six of 22 patients (27.3%) experienced systemic drug reactions after rituximab infusion. Four patients developed a severe flare of MC vasculitis 1 or 2 days after rituximab infusion. Two patients developed serum sickness syndrome 7 and 9 days after the first 1,000 mg rituximab infusion. Compared with patients without drug reactions, those with drug reactions had higher mixed cryoglobulin levels (mean+/-SD 1.4+/-0.82 gm/liter versus 0.71+/-0.77 gm/liter; P=0.0475) and lower C4 levels (mean+/-SD 0.02+/-0.006 gm/liter versus 0.07+/-0.07 gm/liter; P=0.02), and more of them received 1,000 mg high-dose rituximab protocol (50% versus 6.25%; P=0.046). In vitro immunochemical assays showed that rituximab formed a complex with the cryoprecipitating IgMkappa that had rheumatoid factor (RF) activity. Moreover, the in vitro addition of rituximab to serum containing an RF-positive IgMkappa type II mixed cryoglobulin was associated with visibly accelerated cryoprecipitation.

CONCLUSION

In HCV-associated MC vasculitis, rituximab may form a complex with RF-positive IgMkappa, leading to accelerated cryoprecipitation and to severe systemic reactions. Rituximab should be administered with caution in MC vasculitis, with use of the 375 mg protocol and plasma exchanges prior to rituximab infusion in patients with high baseline levels of mixed cryoglobulin.

Mechanisms of adverse drug reactions to biologics

Biologics encompass a broad range of therapeutics that include proteins and other products derived from living systems. Although the multiplicity of target organs often seen with new chemical entities is generally not seen with biologics, they can produce significant adverse reactions. Examples include IL-12 and an anti-CD28 antibody that resulted in patient deaths and/or long stays in intensive care units. Mechanisms of toxicities can be categorized as pharmacological or nonpharmacological, with most, excepting hypersensitivity reactions, associated with the interaction of the agent with its planned target. Unexpected toxicities generally arise as a result of previously unknown biology. Manufacturing quality is a significant issue relative to the toxicity of biologics. The development of recombinant technology represented the single biggest advance leading to humanized products with minimal or no contaminants in comparison to products purified from animal tissues. Nevertheless, the type of manufacturing process including choice of cell type, culture medium, and purification method can result in changes to the protein. For example, a change to the closure system for erythropoietin led to an increase in aplastic anemia as a result of changing the immunogenicity characteristics of the protein. Monoclonal antibodies represent a major class of successful biologics. Toxicities associated with these agents include those associated with the binding of the complementary determining region (CDR) with the target. First dose reactions or infusion reactions are generally thought to be mediated via the Fc region of the antibody activating cytokine release, and have been observed with several antibodies. Usually, these effects (flu-like symptoms, etc.) are transient with subsequent dosing. Although biologics can have nonpharmacologic toxicities, these are less common than with small molecule drugs.

The late adverse events of rituximab therapy--rare but there!

Rituximab, an anti CD20 monoclonal antibody, has now become a cornerstone in the treatment of many CD20 positive hematological malignancies and a variety of autoimmune disorders. In contrast to the acute allergic and cytokine associated reactions, late adverse events of rituximab are indeed uncommon but at the same time probably under-reported. In this review, we detail late adverse events reported since its use in hemato-oncological neoplasias and other disorders. These adverse events include the development of late-onset neutropenia, defects of immune reconstitution with associated immune compromise, infections, progressive multifocal leukoencephalopathy, reactivation of hepatitis, intestinal perforation and interstitial pneumonitis. Possible mechanisms involved in rituximab-associated complications and the pathogenesis of these adverse effects are reviewed and discussed. Evidence based graded recommendations for the management of these adverse effects are proposed.

Translational Mini-Review Series on B Cell-Directed Therapies: Recent advances in B cell-directed biological therapies for autoimmune disorders

B cell-directed therapies are promising treatments for autoimmune disorders. Besides targeting CD20, newer B cell-directed therapies are in development that target other B cell surface molecules and differentiation factors. An increasing number of B cell-directed therapies are in development for the treatment of autoimmune disorders. Like rituximab, which is approved as a treatment for rheumatoid arthritis (RA), many of these newer agents deplete B cells or target pathways essential for B cell development and function; however, many questions remain about their optimal use in the clinic and about the role of B cells in disease pathogenesis. Other therapies besides rituximab that target CD20 are the furthest along in development. Besides targeting CD20, the newer B cell-directed therapies target CD22, CD19, CD40-CD40L, B cell activating factor belonging to the TNF family (BAFF) and A proliferation-inducing ligand (APRIL). Rituximab is being tested in an ever-increasing number of autoimmune disorders and clinical studies of rituximab combined with other biological therapies are being pursued for the treatment of rheumatoid arthritis (RA). B cell-directed therapies are being tested in clinical trials for a variety of autoimmune disorders including RA, systemic lupus erythematosus (SLE), Sjögren's syndrome, vasculitis, multiple sclerosis (MS), Graves' disease, idiopathic thrombocytopenia (ITP), the inflammatory myopathies (dermatomyositis and polymyositis) and the blistering skin diseases pemphigus and bullous pemphigoid. Despite the plethora of clinical studies related to B cell-directed therapies and wealth of new information from these trials, much still remains to be discovered about the pathophysiological role of B cells in autoimmune disorders.

[Rituximab in treatment for neuroimmunological diseases]

Rituximab, a human-mouse chimeric CD20 monoclonal antibody that depletes CD20-positive B cells, has already demonstrated efficacy in hematologic and rheumatologic diseases. Treatment with rituximab results in depletion of CD20-positive cells via multiple mechanisms, including complement-mediated or antibody-dependent cytotoxicity and apoptosis. Recent histopathologic and immunologic studies reveal an influence of B cells on the development and perpetuation of many chronic inflammatory diseases of the nervous system. Promising results with rituximab were already reported in the therapy of myasthenia gravis, immunoneuropathies, neuromyelitis optica, and multiple sclerosis, in which first controlled studies have been recently published. In this review we summarize available data from these reports and also discuss possible underlying molecular mechanisms.

Pegylated interferon plus rituximab in advanced stage, indolent lymphoma: is there CD20 antigen upregulation?

The anti-CD20 monoclonal antibody, rituximab, and interferon alpha (IFN) are active agents in advanced stage, indolent lymphoma. Some data obtained in vitro suggest upregulation of CD20 by IFN, and clinical trials have reported additive or synergistic activity of IFN with rituximab. A prospective phase II study in advanced stage, follicular and non-follicular indolent lymphoma was performed. Peginterferon alpha 2b (pegIFN) 0.5 microg/kg s.c. weekly x 6 and rituximab 375 mg/m2 i.v. weekly x 4 (beginning on week 3 of pegIFN) was administered. Quantitative CD20 antigen was measured pre-treatment and pre-rituximab in lymph node aspirates. Nine patients were treated: one complete response and three partial responses; however, all relapsed within 12 months and two were withdrawn for grade 3 toxicity (both with serum sickness). No up-regulation of CD20 was documented in seven patients studied (median change in CD20: decrease by 11.9%). PegIFN plus rituximab as delivered in this study is not recommended. PegIFN does not appear to upregulate CD20 expression in peripheral lymph node tumor cells.

Review and expert opinion on prevention and treatment of infliximab-related infusion reactions

Infliximab (Remicade; Schering-Plough, Kenilworth, NJ, U.S.A.) is a chimeric monoclonal antibody that acts as a tumour necrosis factor-alpha inhibitor. Infliximab is registered for the treatment of rheumatoid arthritis, psoriatic arthritis, Crohn disease, ulcerative colitis, ankylosing spondylitis and plaque-type psoriasis. Like other foreign protein-derived agents, infliximab may lead to infusion reactions during and after infusion. Infusion reactions occur in 3-22% of patients with psoriasis treated with infliximab. Most of these reactions are mild or moderate and only few are severe. Nevertheless, they may lead to discontinuation of treatment. As infliximab for psoriasis is prescribed as a last resort and is in most cases very effective, discontinuation of treatment is undesirable. With proper care and prevention of the infusion reactions the need to discontinue treatment with infliximab can be diminished. The objective of this article is to present a guideline for the management of infliximab-related infusion reactions, based on the best available evidence. This guideline can be used in patients with psoriasis as well as in dermatology patients receiving infliximab for off-label indications such as hidradenitis suppurativa or pyoderma gangrenosum.

Safety of biologic therapy in rheumatoid arthritis and other autoimmune diseases: focus on rituximab

OBJECTIVES

To review the safety of biologic agents used to treat rheumatoid arthritis (RA) and other autoimmune diseases, with a focus on rituximab.

METHODS

Information was gathered from a search of the PubMed database and from major congress abstract listings through June 2007.

RESULTS

Rituximab is approved for treating RA in patients with an inadequate response to TNF inhibitors and is under study in other indications for RA and other autoimmune disorders. The current safety profile of rituximab in RA is known from Phase II and III studies conducted preapproval, treating approximately 750 patients, as well as from long-term extension studies with repeated therapy. Clinical trials have established that the most common adverse events are infusion-associated reactions, seen in 29 to 40% of patients, most of which are mild to moderate and occur following the first rituximab infusion, with incidence and severity decreasing with subsequent infusions. Rates of infections and serious infections to date are within the range expected for RA patients treated with other biologic agents, but the longer term effects of B-cell depletion and the effects of repeated treatment on the risk of infections are uncertain. Information is limited for rituximab safety in other autoimmune disorders but current data do not suggest that there is a significant difference in adverse events from that previously reported.

CONCLUSIONS

Rituximab is an important addition to the rheumatologist's armamentarium for the treatment of difficult RA and ongoing trials will determine its utility in other indications for RA and other autoimmune conditions. The true safety profile of rituximab will emerge as larger numbers of patients are treated in routine clinical practice.

B-cell-directed therapies in systemic lupus erythematosus

OBJECTIVE

Owing to their ability to promote the onset and flares of systemic lupus erythematosus (SLE), B-cells are now established as key players in the pathogenesis of the disease, and, therefore, have become a major therapeutic focus in SLE. In this article, we review the literature on B-cell-directed therapies for SLE focusing on B-cell depletion, B-cell tolerance, costimulatory signals, and cytokines that affect B-cell survival and activation.

METHODS

The clinical trials reviewed in this article were accessed from the PubMed database (www.pubmed.gov) and Clinical Trials database (www.clinicaltrials.gov) through an English language search of the literature published between January 2002 and March 2007. Keywords included the following terms: B-cells, SLE, and therapy.

RESULTS

Seventeen completed clinical trials enrolling 973 patients and 5 ongoing studies with anticipated enrollment of 785 patients were reviewed. Novel SLE therapies that target B-cells directly or indirectly were included. B-cell-depleting therapies with the monoclonal antibodies rituximab and epratuzumab have shown good therapeutic results. On the contrary, the well-studied B-cell tolerogen LJP 394 has not demonstrated much clinical benefit. Studies targeting costimulatory pathways have shown variable results; clinical trials with anti-CD40L antibody were terminated because of thromboembolic events, whereas studies targeting the B7-CD28 pathway seem promising. Anticytokine agents against B-lymphocyte stimulator (BLyS), interleukin (IL)-10, IL-6, and interferon alpha (IFN-alpha) are the newcomers that need further evaluation in the treatment of SLE.

CONCLUSIONS

Progress in technology has led to the variety of B-cell-directed therapies. In contrast to general immunosuppressants, novel treatments that interfere with specific aspects of B-cell functions create the possibility of developing targeted therapeutic approaches for specific subpopulations of lupus patients.

Hypersensitivity reactions to biological agents with special emphasis on tumor necrosis factor-alpha antagonists

PURPOSE OF REVIEW

Several biological agents have been introduced into the drug market and more are emerging. Adverse reactions to these agents have recently been classified into five different subtypes. Some of these reactions are frequent but without consequences for the patients. Others are less frequent but potentially life-threatening, and they include allergic reactions.

RECENT FINDINGS

Hypersensitivity reactions are well described adverse drug reactions, corresponding to the ss-type of the newly proposed classification of adverse reactions induced by biological agents. We focus our search on tumor necrosis factor-alpha antagonists, as they represent a dramatic improvement in the therapy of both rheumatic and inflammatory bowel diseases and because adverse reactions have been closely scrutinized. We also add cases from our own experience. We found very few properly documented allergic reactions.

SUMMARY

Hypersensitivity reactions to tumor necrosis factor-alpha antagonists are not rare. Whether these manifestations have to be considered type beta or type gamma reactions is still a matter of debate. There is a need for allergological tests in vivo and in vitro.