A tale of two antibodies: obinutuzumabversusrituximab

Lupus nephritis: new progress in diagnosis and treatment

Systemic lupus erythematosus (SLE) is a chronic multifactorial autoimmune disease that affects many organs, including the kidney. Lupus nephritis (LN) is a common manifestation characterized by heterogeneous clinical and histopathological findings, and often associates with poor prognosis. The diagnosis and treatment of LN is challenging, depending largely on renal biopsy, and there is no reliable non-invasive LN biomarker. Up to now, the complete remission rate of LN is only 20%∼30% after receiving six months of standard treatment, which is far from satisfactory. Moreover, adverse reactions to immunosuppressants, especially glucocorticoids, further compromise the prognosis of LN. Biological reagents targetting autoimmune responses and inflammatory pathways, bring hope to the treatment of intractable lupus. The European Renal Association-European Dialysis and Transplant Association (EULAR/ERA-EDTA) and KDIGO (Kidney Disease: Improving Global Outcomes) have been working on and launched the recommendations for the management of LN. In this review, we update our knowledge in the pathogenesis, diagnosis, and management of LN and prospect for the future potential targets in the management of LN.

Obinutuzumab in the treatment of B-cell malignancies: a comprehensive review

The type II anti-CD20 antibody obinutuzumab has structural and mechanistic features that distinguish it from the first anti-CD20 antibody, rituximab, which have translated into improved efficacy in phase III trials in indolent non-Hodgkin lymphoma and chronic lymphocytic leukemia (CLL). These gains have been shown through improvements in, and/or increased durability of, tumor response, and increases in progression-free survival in patients with CLL or follicular lymphoma (FL). Ongoing research is focusing on the use of biomarkers and the development of chemotherapy-free regimens involving obinutuzumab. phase II trials of such treatment regimens have shown promise for CLL, FL and mantle cell lymphoma, while phase III trials have highlighted obinutuzumab as the antibody partner of choice for novel agents in first-line CLL treatment.

Improved Therapy of B-Cell Non-Hodgkin Lymphoma by Obinutuzumab-Dianthin Conjugates in Combination with the Endosomal Escape Enhancer SO1861

Immunotoxins do not only bind to cancer-specific receptors to mediate the elimination of tumor cells through the innate immune system, but also increase target cytotoxicity by the intrinsic toxin activity. The plant glycoside SO1861 was previously reported to enhance the endolysosomal escape of antibody-toxin conjugates in non-hematopoietic cells, thus increasing their cytotoxicity manifold. Here we tested this technology for the first time in a lymphoma in vivo model. First, the therapeutic CD20 antibody obinutuzumab was chemically conjugated to the ribosome-inactivating protein dianthin. The cytotoxicity of obinutuzumab-dianthin (ObiDi) was evaluated on human B-lymphocyte Burkitt’s lymphoma Raji cells and compared to human T-cell leukemia off-target Jurkat cells. When tested in combination with SO1861, the cytotoxicity for target cells was 131-fold greater than for off-target cells. In vivo imaging in a xenograft model of B-cell lymphoma in mice revealed that ObiDi/SO1861 efficiently prevents tumor growth (51.4% response rate) compared to the monotherapy with ObiDi (25.9%) and non-conjugated obinutuzumab (20.7%). The reduction of tumor volume and overall survival was also improved. Taken together, our results substantially contribute to the development of a combination therapy with SO1861 as a platform technology to enhance the efficacy of therapeutic antibody-toxin conjugates in lymphoma and leukemia.

3D Models as a Tool to Assess the Anti-Tumor Efficacy of Therapeutic Antibodies: Advantages and Limitations

Therapeutic monoclonal antibodies (mAbs) are an emerging and very active frontier in clinical oncology, with hundred molecules currently in use or being tested. These treatments have already revolutionized clinical outcomes in both solid and hematological malignancies. However, identifying patients who are most likely to benefit from mAbs treatment is currently challenging and limiting the impact of such therapies. To overcome this issue, and to fulfill the expectations of mAbs therapies, it is urgently required to develop proper culture models capable of faithfully reproducing the interactions between tumor and its surrounding native microenvironment (TME). Three-dimensional (3D) models which allow the assessment of the impact of drugs on tumors within its TME in a patient-specific context are promising avenues to progressively fill the gap between conventional 2D cultures and animal models, substantially contributing to the achievement of personalized medicine. This review aims to give a brief overview of the currently available 3D models, together with their specific exploitation for therapeutic mAbs testing, underlying advantages and current limitations to a broader use in preclinical oncology.

Polatuzumab vedotin in relapsed / refractory aggressive B-cell lymphoma

INTRODUCTION

Diffuse large B-cell lymphoma (DLBCL) is the most common aggressive lymphoma histology. Outcomes for patients with relapsed or refractory (R/R) disease remain suboptimal. Polatuzumab vedotin (polatuzumab) is a recently approved antibody drug conjugate that targets CD79b, with a tubulin toxin payload, that has demonstrated significant clinical activity and an acceptable toxicity profile when administered with both anti-CD20 monoclonal antibodies and chemotherapy in clinical trials.

AREAS COVERED

In this article, we discuss the early-phase trials supporting the accelerated FDA approval of polatuzumab for patients with R/R DLBCL and review the status of and data from ongoing trials combining polatuzumab with other agents.

EXPERT OPINION

Polatuzumab is an important new tool for the management of patients with R/R DLBCL who are ineligible for or who relapse following standard second-line therapies. Combinations of polatuzumab with other agents may represent an opportunity to improve outcomes for this difficult to treat population. The recent publication of the POLARIX trial (NCT03274492) incorporating polatuzumab in the frontline treatment of DLBCL may impact the future role of this agent in the R/R setting.

Influencing Factors of Health Technology Assessment to Orphan Drugs: Empirical Evidence in England, Scotland, Canada, and Australia

This study summarizes the intrinsic criteria for the recommendation of orphan drugs in England, Scotland, Canada, and Australia with the aim of understanding the rationale for the variability in decision-making and to provide a reference for the establishment of criteria in the process of access to health insurance for orphan drugs in different countries and the construction of national uniform criteria. A comparative analysis of 60 health technology assessment (HTA) guidelines of 15 drug-indication pairs appraised by four countries (England, Scotland, Canada, and Australia) from 2017 to 2018 was done, including an in-depth analysis of a case study. Agreement levels were measured using kappa scores. Associations were explored through correspondence analysis. The four countries possess some homogeneity in the assessment, but each has its own preferences. Poor agreement exists between England, Scotland, and Canada (−0.41 < kappa score < 0.192). In the correspondence analysis, England placed more emphasis on treatment methods in terms of control type when making recommendations. Canada and Scotland focused more on trial type with Canada placing more emphasis on phase III and open-label trials and on cost-utility analysis, while Australia was less studied in terms of economic models. Different countries have different goals when establishing HTA decisions for orphan drugs due to their different degrees of orphan drug coverage. Different countries should not only combine their unique values of clinical benefit and cost-effectiveness in the assessment of orphan drugs but also give different weights during the HTA process, after considering account the development of the country itself.

Treatment of indolent lymphoma

Treatment of indolent lymphoma has improved significantly in recent decades since the advent of rituximab (anti-CD20 monoclonal antibody). Although, some patients with limited disease can be cured with radiation therapy alone, most patients experience disease progression and recurrence during follow-up despite early initiation of treatment. Thus, watch-and-wait is still regarded the standard for asymptomatic patients. Patients with indolent lymphoma have a significant heterogeneity in terms of tumor burden, symptoms (according to anatomical sites) and the need for instant therapy. Therefore, the initiation of treatment and treatment option should be decided with a clear goal in each patient according to the need for therapy and clinical benefits with the chosen treatment. In this review, we cover the current treatment of follicular lymphoma and marginal zone lymphoma.

B cells in autoimmune hepatitis: bystanders or central players?

B cells are central for the adaptive immune system to mount successful immune responses not only as antibody producers but also as regulators of cellular immunity. These multifaceted features are also reflected in autoimmunity where autoreactive B cells can fuel disease by production of cytotoxic autoantibodies, presentation of autoantigens to autoreactive T cells, and secretion of cytokines and chemokines that either promote detrimental immune activation or impair regulatory T and B cells. The role of B cells and autoantibodies in autoimmune hepatitis (AIH) have been controversially discussed, with typical autoantibodies and hypergammaglobulinemia indicating a key role, while strong HLA class II association suggests T cells as key players. In this review, we summarize current knowledge on B cells in AIH and how different B cell subpopulations may drive AIH progression beyond autoantibodies. We also discuss recent findings of B cell-directed therapies in AIH.

Strategies to Control Therapeutic Antibody Glycosylation during Bioprocessing: Synthesis and Separation

Glycosylation can be a critical quality attribute in biologic manufacturing. In particular, it has implications on the half‐life, immunogenicity, and pharmacokinetics of therapeutic monoclonal antibodies (mAbs), and must be closely monitored throughout drug development and manufacturing. To address this, advances have been made primarily in upstream processing, including mammalian cell line engineering, to yield more predictably glycosylated mAbs and the addition of media supplements during fermentation to manipulate the metabolic pathways involved in glycosylation. A more robust approach would be a conjoined upstream–downstream processing strategy. This could include implementing novel downstream technologies, such as the use of Fc γ‐based affinity ligands for the separation of mAb glycovariants. This review highlights the importance of controlling therapeutic antibody glycosylation patterns, the challenges faced in terms of glycosylation during mAb biosimilar development, current efforts both upstream and downstream to control glycosylation and their limitations, and the need for research in the downstream space to establish holistic and consistent manufacturing processes for the production of antibody therapies.

Single-Agent Mosunetuzumab Shows Durable Complete Responses in Patients With Relapsed or Refractory B-Cell Lymphomas: Phase I Dose-Escalation Study

PURPOSE

Mosunetuzumab is a bispecific antibody targeting CD20 and CD3 that redirects T cells to engage and eliminate malignant B cells and is being developed for relapsed or refractory (R/R) B-cell non-Hodgkin lymphomas (B-NHLs).

METHODS

This first-in-human trial (ClinicalTrials.gov identifier: NCT02500407) evaluated the safety and tolerability and efficacy of mosunetuzumab in patients with R/R B-NHL and established the recommended phase II dose. Data from dose escalation are presented. Single-agent mosunetuzumab was administered intravenously in 3-week cycles, at full dose in cycle 1 day 1 (group A) or with ascending (step-up) doses during cycle 1 on days 1, 8, and 15 (group B), for eight or 17 cycles on the basis of tumor response.

RESULTS

Two hundred thirty patients were enrolled. Doses up to 2.8 mg and 60 mg were assessed in groups A and B, respectively; maximum tolerated dose was not exceeded. In group B (n = 197), common adverse events (≥ 20% of patients) were neutropenia (28.4%), cytokine release syndrome (27.4%), hypophosphatemia (23.4%), fatigue (22.8%), and diarrhea (21.8%). Cytokine release syndrome was mostly low-grade (grade ≥ 3: 1.0%) and mainly confined to cycle 1. Across the doses investigated (group B), best overall response rates were 34.9% and 66.2% in patients with aggressive and indolent B-NHL, respectively, and complete response rates were 19.4% and 48.5%. Among patients with a complete response, the median duration of response was 22.8 months (95% CI, 7.6 to not estimable) and 20.4 (95% CI, 16 to not estimable) in patients with aggressive and indolent B-NHL, respectively.

CONCLUSION

Mosunetuzumab, administered with step-up dosing, has a manageable safety profile and induces durable complete responses in R/R B-NHL. The expansion stage of the study is ongoing at the dose level of 1/2/60/60/30 mg selected for further study.

Systemic sclerosis complicated with renal thrombotic microangiopathy: a case report and literature review

Background

Systemic sclerosis (SSc) may overlap with other connective tissue diseases, which is named overlap syndrome. Scleroderma renal crisis (SRC) is a rare but severe complication of SSc. SSc related thrombotic microangiopathy (SSc-TMA) is an infrequent pathology type of SRC, while SSc-TMA accompanied by overlap syndrome is very rare.

Case presentation

This study reported a case of acute kidney injury (AKI) accompanied with overlap syndrome of SSc, systemic lupus erythematosus (SLE) and polymyositis (PM). The renal pathology supported the diagnosis of SSc-TMA but not SLE or PM-related renal injury, characterized by renal arteriolar thrombosis, endothelial cells edema, little cast in tubules and mild immune complex deposition. The primary TMA related factors (ADAMTS13 and complement H factor) were normal. Thus, this case was diagnosed as secondary TMA associated with SSc. The patient was treated with renin angiotensin system inhibitors, sildenafil, supportive plasma exchange/dialysis, and rituximab combined with glucocorticoids. After 2 months of peritoneal dialysis treatment, her renal function recovered and dialysis was stopped.

Conclusion

This study presented a case of SSc-TMA with overlap syndrome. Rituximab can be used as a treatment option in patients with high SRC risk or already manifesting SRC.

Potential therapeutic strategies in chronic inflammatory demyelinating polyradiculoneuropathy

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an autoimmune neuropathy involving peripheral nerve and nerve roots. The pathological hallmark of CIDP is macrophage-induced demyelination. Antibodies against nerve fibers, complement decomposition, abnormalities in plasma and cerebrospinal fluid cytokine profile, and changes of peripheral blood cell proportion were also reported in CIDP patients. These findings in immunopathology provide support for the introduction of potential therapeutic options for the treatment of CIDP. In this review, we systematically listed the potential therapeutic strategies targeting different components of the immune system by comparing the treatment of other autoimmune inflammatory diseases of the nervous system. Several ongoing clinical trials will assess the efficacy and safety of potential CIDP treatments.

Is there a role for anti-CD20 antibodies in CLL?

Anti-CD20 monoclonal antibodies (mAbs) have revolutionized the treatment of chronic lymphocytic leukemia (CLL) by improving survival of patients with CLL in conjunction with chemotherapy. However, the novel targeted agents such as Bruton tyrosine kinase inhibitors (BTKis) and venetoclax have now mostly replaced chemotherapy in frontline treatment of CLL. Several clinical trials have been conducted to examine the role of anti-CD20 mAbs in combination with BTK inhibitors and venetoclax. Addition of rituximab to ibrutinib does not improve progression-free survival (PFS) of treatment-naive patients with CLL, possibly related to ibrutinib's antagonistic effect on anti-CD20 antibodies. Alternatively, addition of a glycoengineered anti-CD20 mAb obinutuzumab to a more selective BTKi acalabrutinib may improve PFS but does not improve overall survival of patients with CLL in the frontline setting, pending long-term follow-up. Thus, we suggest that the addition of an anti-CD20 mAb to a BTKi is of most benefit to patients with autoimmune cytopenia or rapidly progressive disease. In contrast to BTKis, combination of fixed-duration venetoclax and anti-CD20 mAb can induce deep remission with high rates of undetectable minimal residual disease, correlating with improved survival of patients with CLL in both frontline and relapsed/refractory settings. In this review, we discuss clinical trials of BTKis and venetoclax that have investigated the role of anti-CD20 mAbs in frontline and relapsed settings of CLL treatment. We also provide an algorithm suggesting how anti-CD20 mAbs may be incorporated in the treatment of patients with CLL, including specific scenarios.

Successful treatment of prolonged COVID-19 with Bamlanivimab in a patient with severe B-Cell aplasia due to treatment with an anti-CD20 monoclonal antibody: A case report

A 71-year-old female patient with B-cell depletion due to treatment with an anti-CD20 monoclonal antibody was admitted for worsening COVID-19. Overall, she had persistent viral shedding, worsening respiratory failure, and progressive pneumonia that did not improve despite dexamethasone and antibiotic therapy. After administration of bamlanivimab, a monoclonal antibody with high affinity for the receptor-binding domain of the SARS-CoV-2 spike protein, inflammatory markers rapidly decreased, SARS-CoV2 RT-PCR became negative, and the patient improved clinically and radiologically. In conclusion, we demonstrated successful treatment of prolonged COVID-19 in a patient with severe B-cell aplasia with a virus-neutralizing monoclonal antibody.

Pembrolizumab treatment of inflammatory progressive multifocal leukoencephalopathy: a report of two cases

Progressive multifocal leukoencephalopathy (PML) is a rare but devastating neurological disease caused by reactivation of the JC virus in susceptible individuals. The illness has classically been associated with the human immunodeficiency virus (HIV) and multiple sclerosis (MS) patients who are treated with natalizumab. It is also associated with haematological malignancies, organ transplantation, autoimmune disease and immunodeficiency. Aside from natalizumab, a range of other immunomodulators including obinutuzumab and rituximab have been associated with PML. The nature of these associations is unclear due to the overall low incidence of PML associated with these drugs and the fact that most patients will have other confounding risk factors for developing the disease. There is no known effective treatment available for PML in the non-HIV, non-MS cohort. Recent case studies and series have proposed that pembrolizumab, an anti-PD-1 immune checkpoint inhibitor, may be a potentially efficacious option for these patients. We present two cases of non-HIV, non-MS patients with PML who were treated with pembrolizumab with little clinical benefit. The literature surrounding pembrolizumab use in PML is discussed, with a focus on potential indicators of successful outcomes for patients who receive this therapy.

Neutropenic Fever in a Patient With SARS-CoV-2-Induced Hemophagocytic Lymphohistiocytosis (HLH)

Hemophagocytic lymphohistiocytosis (HLH) is a severe systemic inflammatory syndrome that is often fatal. In the adult population, it is believed to develop secondary to immune dysregulation due to rheumatologic, infectious, malignant, and recently, immunomodulatory drugs. It has been well documented that infectious etiologies can lead to HLH however to date there is a paucity of case reports of HLH stemming from the 2019 novel coronavirus (SARS-CoV-2). Furthermore, it is well established that overlap exists between the extensive hyper-inflammatory syndromes produced from both HLH and severe COVID-19 infection. Here, we present a case of COVID-19-associated HLH with recurrent neutropenic fever in a patient with controlled follicular non-Hodgkin lymphoma who received treatment with etoposide after continued hospital admissions with refractory medical treatment.

Deconvoluting the heterogeneity of SLE: The contribution of ancestry

Systemic lupus erythematosus (SLE) is a multiorgan autoimmune disorder with a prominent genetic component. Evidence has shown that individuals of non-European ancestry experience the disease more severely, exhibiting an increased incidence of cardiovascular disease, renal involvement, and tissue damage compared with European ancestry populations. Furthermore, there seems to be variability in the response of individuals within different ancestral groups to standard medications, including cyclophosphamide, mycophenolate, rituximab, and belimumab. Although the widespread application of candidate gene, Immunochip, and genome-wide association studies has contributed to our understanding of the link between genetic variation (typically single nucleotide polymorphisms) and SLE, despite decades of research it is still unclear why ancestry remains a key determinant of poorer outcome in non-European-ancestry patients with SLE. Here, we will discuss the impact of ancestry on SLE disease burden in patients from diverse backgrounds and highlight how research efforts using novel bioinformatic and pathway-based approaches have begun to disentangle the complex genetic architecture linking ancestry to SLE susceptibility. Finally, we will illustrate how genomic and gene expression analyses can be combined to help identify novel molecular pathways and drug candidates that might uniquely impact SLE among different ancestral populations.

Rituximab-Associated Flare of Cryoglobulinemic Vasculitis

Background

Patients with cryoglobulinemic vasculitis (CV) can develop disease flare after rituximab administration. The objective of our study was to describe the prevalence, clinical characteristics, predisposing factors, and outcomes of patients with rituximab-associated flare of CV.

Methods

We conducted a retrospective study in a tertiary referral center until March 25, 2020.

Results

Among 64 patients with CV who received rituximab therapy in our center, 14 (22%) developed disease flare. Median age was 67.5 years. Seven patients (50%) had type II CV and the other half had either type I (n = 6) or type III (n = 1). Twelve patients (86%) had an underlying B-cell lymphoproliferative disorder as the cause of their CV. CV flare occurred after a median time of 5.5 days (range: 2–8 days). The organ systems most involved were the skin (n = 10), kidneys (n = 5), and peripheral nerves (n = 3). Five patients (36%) developed acute kidney injury (AKI), 3 of whom presented with nephritic syndrome secondary to biopsy-proven membranoproliferative glomerulonephritis. Treatment was directed against the underlying disease in addition to supportive care. Patients who developed flare were more likely to have B-cell lymphoproliferative disorder as the underlying etiology of their CV (P = 0.03). Eight patients (57%) died after a median time of 27 months.

Conclusions

Rituximab-associated flare can occur in all types of CV, tends to arise approximately 2 days and less than 1 week after rituximab administration, and is more likely to happen in patients with an underlying B-cell lymphoproliferative disorder. It does not indicate treatment failure, and rituximab should not be abandoned altogether. AKI is a common manifestation, and mortality rate at 2 years is high.

Approach to Highly Sensitized Kidney Transplant Candidates and a Positive Crossmatch

Human leukocyte antigen (HLA)-incompatible kidney transplantation offers survival benefit compared with ongoing dialysis. There have been considerable advances in the last decade to allow for increased access to transplant for the HLA-sensitized kidney transplant candidates. These include increased priority in the kidney allocation system, kidney paired donation, and novel desensitization strategies. A better understanding of the role of B cells, plasma cells, and complement and inflammatory cytokines in the pathophysiology of HLA antibody-mediated allograft injury has led to the use of novel therapeutics for desensitization and treatment of antibody-mediated rejection. Here we discuss current approaches to kidney transplantation in HLA-sensitized kidney transplant candidates.

The Outcome of COVID-19 in Patients with a History of Taking Rituximab: A Narrative Review

Coronavirus disease 2019 (COVID-19) is a recently emerging disease caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Notably, the safety of immunosuppressive medications is a major concern during an infectious disease pandemic. Rituximab (RTX), as a monoclonal antibody against CD20 molecule, is widely used for the treatment of various diseases, mostly autoimmune diseases and some malignancies. Previous studies indicated that RTX, as an immunosuppressive medication, may be associated with the increased risk of infections. Moreover, given the wide use of RTX, a necessity of determining the different aspects of RTX use in the COVID-19 era is strongly felt. We reviewed current studies on the clinical courses of patients with SARS-CoV-2 infection. It appears that the use of RTX does not increase morbidity and mortality in most patients. However, underlying diseases and other concomitant medications may play a role in the disease course, while the concerns of vaccine efficacy in patients receiving RTX still need to be addressed. Therefore, more controlled studies are needed for a better conclusion.

Comparison of CD20 Binding Affinities of Rituximab Produced in Nicotiana benthamiana Leaves and Arabidopsis thaliana Callus

Plants are promising drug-production platforms with high economic efficiency, stability, and convenience in mass production. However, studies comparing the equivalency between the original antibodies and those produced in plants are limited. Amino acid sequences that constitute the Fab region of an antibody are diverse, and the post-transcriptional modifications that occur according to these sequences in animals and plants are also highly variable. In this study, rituximab, a blockbuster antibody drug used in the treatment of non-Hodgkin's lymphoma, was produced in Nicotiana benthamiana leaves and Arabidopsis thaliana callus, and was compared to the original rituximab produced in CHO cells. Interestingly, the epitope recognition and antigen-binding abilities of rituximab from N. benthamiana leaves were almost lost. In the case of rituximab produced in A. thaliana callus, the specific binding ability and CD20 capping activity were maintained, but the binding affinity was less than 50% of that of original rituximab from CHO cells. These results suggest that different plant species exhibit different binding affinities. Accordingly, in addition to the differences in PTMs between mammals and plants, the differences between the species must also be considered in the process of producing antibodies in plants.

Efficacy and mechanism of the anti-CD38 monoclonal antibody Daratumumab against primary effusion lymphoma

Primary effusion lymphoma (PEL) is a rare, aggressive B cell non-Hodgkin's lymphoma of the body cavities with malignant effusions. The prognosis is poor, and no optimal treatment has been established. CD38 is a type II transmembrane glycoprotein known to overexpress in multiple myeloma (MM). Daratumumab (DARA), a human CD38-targeting monoclonal antibody (mAb), is approved for MM treatment. In this study, we found expression of CD38 on PEL cells and assessed the anti-PEL activity of DARA. We found that both KHYG-1 and N6 (CD16-transfected KHYG-1) NK cell lines showed direct killing activity against PEL cells with induction of CD107a, and NK-mediated cytotoxicity by N6NK (CD16⁺) cells increased with DARA treatment. We confirmed direct NK activity and antibody-dependent cell cytotoxicity (ADCC) by expanded NK cells, indicating that DARA has high ADCC activity. We elucidated the antibody-dependent cell phagocytosis (ADCP) by using human monocyte-derived macrophages (MDMs) and mouse peritoneal macrophages. DARA also showed potent complement-dependent cytolysis (CDC) toward PEL. DARA also induced PEL cell death in the presence of a cross-linking antibody. Moreover, treatment with DARA inhibited tumor growth in a PEL xenograft mouse model. These results provide preclinical evidence that Ab targeting of CD38 could be an effective therapeutic strategy for the treatment of PEL.

Development of a cell line-based assay to measure the antibody-dependent cellular cytotoxicity of a canine therapeutic antibody

Antibody drugs are one of the most important therapeutic modalities in cancer treatment. Antibody drugs for canine cytotoxicity have been developed, and the most important way to evaluate the function of antibody drugs in vitro is to measure the antibody-dependent cellular cytotoxicity (ADCC) activity. However, a good method for measuring the ADCC activity of antibody drugs for dogs has not yet been developed. This study generated a cell line of NK-92 cells, a human natural killer cell line, transfected with canine CD16 and γ-chain as effector cells. A20 cells expressing canine CD20 were used as target cells, and a system for ADCC activity was established using an anti-dog CD20 antibody. The assay generated very consistent results. This is an applicable method for measuring canine ADCC activity and can be used for various antigen-antibody combinations to develop canine antibody drugs with cytotoxic activity in the future.

Recent Advances in the Management of Patients with Relapsed/Refractory Follicular Lymphoma

Advanced follicular lymphoma (FL) often relapses after front-line chemoimmunotherapy, and many patients will eventually require subsequent therapy. In 2021, two new therapies were granted approval by the Food and Drug Administration (FDA), including the PI3Kδ inhibitor umbralisib and the chimeric antigen receptor–T-cell therapy (CAR-T) axicabtagene ciloleucel. Herein, we present the latest advances in the management of FL, discussing the recently approved therapies in the relapsed and refractory (R/R) setting and various new therapeutic modalities that have the potential to change the treatment landscape and natural history of R/R FL.

Chemotherapy-Free Management of Follicular and Marginal Zone Lymphoma

Many patients with follicular (FL) or marginal zone lymphoma (MZL) are not eligible to receive immunochemotherapy due to advanced age or comorbidities. Recent innovations in the treatment of these indolent lymphomas provide options for multiple lines of chemotherapy-free management. More research is needed to determine which older patients are best served by a chemotherapy-free approach in the context of geriatric vulnerabilities. In the first line, regardless of disease burden, rituximab monotherapy can provide high rates of disease control with minimal toxicity, while judicious use of brief maintenance extends the duration of response. Radioimmunotherapy using ibritumomab tiuxetan is an effective and safe post-rituximab consolidation for older patients who have <25% bone marrow involvement. The combination of rituximab and lenalidomide, although “chemotherapy-free”, does not improve tolerability over immunochemotherapy. However, studies support lower doses and shorter duration of lenalidomide exposure as a means to improve safety without materially compromising efficacy for older individuals. Extranodal MZL can often be effectively controlled with low-dose radiation therapy, and splenic MZL has excellent outcomes with rituximab monotherapy. For many patients with relapsed FL/MZL, simple retreatment with anti-CD20 antibodies will prove sufficient. Other currently available options for relapsed/refractory disease include ibritumomab tiuxetan, lenalidomide with rituximab, umbralisib as a potentially less toxic PI3K inhibitor, ibrutinib (for MZL), and tazemetostat (for FL, especially with EZH2 mutation). Emerging data with novel forms of immunotherapy (antibody-drug conjugates like polatuzumab vedotin or loncastuximab tesirine; T-cell-engaging bispecific antibodies like mosunetuzumab or epcoritamab; and chimeric antigen receptor CAR T-cells like axicabtagene ciloleucel) suggest that immune-directed approaches can produce very high and potentially durable responses in FL/MZL with limited toxicities, further obviating the need for chemotherapy.

Biobetters in patients with immune-mediated inflammatory disorders: An international Delphi consensus

Several efforts have been made to improve the available therapeutic armamentarium of patients with immune-mediated inflammatory disorders (IMIDs) leading to the development of biobetters. To date, there is no commonly accepted definition of biobetters. Sixteen physicians with expertise in the field of IMIDs from eleven countries attended a virtual international consensus meeting to provide for the first time a definition of biobetter and to identify unmet needs on this topic. Improvements in clinical outcomes and drug pharmacology were considered crucial for the definition of biobetters, while safety profile and patient acceptability were not. In addition, an appropriate balance between clinical outcomes and costs and a shared decision between physicians and patients should guide the decision to use a biobetter. Clinical studies are required to validate the biobetter definition and to investigate their role in the management of patients with IMIDs.

Spinal anesthesia in a patient on monoclonal antibody treatment: a poisoned chalice? A case report

BACKGROUND

Paraplegia is a rare complication of spinal anesthesia.

CASE PRESENTATION

We report a case of a 68-year-old man who developed postoperative paraplegia and hypoesthesia after spinal anesthesia for an otherwise uncomplicated transurethral resection of the prostate. Acute transverse myelitis was diagnosed based on urgent MRI. A prior history of similar though less severe neurological symptoms after obinutuzumab treatment for follicular lymphoma suggested a potential causative role for obinutuzumab, a novel monoclonal antibody that has not been associated with such devastating neurological side effects yet. High-dose steroid treatment partially attenuated the symptoms, but debilitating hypoesthesia and motor deficit remained present 3 months postoperatively.

CONCLUSION

The presented case warrants caution when performing neuraxial anesthesia in patients on monoclonal antibody therapies.

Weathering the storm: COVID-19 infection in patients with hematological malignancies

The coronavirus disease 2019 (COVID-19) is an emerging infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Within a matter of months, this highly contagious novel virus has led to a global outbreak and is still spreading rapidly across continents. In patients with COVID-19, underlying chronic diseases and comorbidities are associated with dismal treatment outcomes. Owing to their immunosuppressive status, patients with hematological malignancies (HMs) are at an increased risk of infection and have a worse prognosis than patients without HMs. Accordingly, intensive attention should be paid to this cohort. In this review, we summarize and analyze specific clinical manifestations for patients with coexisting COVID-19 and HMs. Furthermore, we briefly describe customized management strategies and interventions for this susceptible cohort. This review is intended to guide clinical practice.

Managing the Impact of Immunogenicity in an Era of Immunotherapy: From Bench to Bedside

Biotherapeutics have revolutionized our ability to treat life-threatening diseases. Despite clinical success, the use of biotherapeutics has sometimes been limited by the immune response mounted against them in the form of anti-drug antibodies (ADAs). The multifactorial nature of immunogenicity has prevented a standardized approach for assessing this and each of the assessment methods developed so far does not exhibit high enough reliability to be used alone, due to limited predictiveness. This prompted the Roche Pharma Research and Early Development (pRED) Immunogenicity Working Group to establish an internal preclinical immunogenicity toolbox of in vitro/in vivo approaches and accompanying guidelines for a harmonized assessment and management of immunogenicity in early development. In this article, the complex factors influencing immunogenicity and their associated clinical ramifications are discussed to highlight the importance of an end-to-end approach conducted from lead optimization to clinical candidate selection. We then examine the impact of the resulting lead candidate categorization on the design and implementation of a multi-tiered ADA/immunogenicity assay strategy prior to phase I (entry into human) through early clinical development. Ultimately, the Immunogenicity Toolbox ensures that Roche pRED teams are equipped to address immunogenicity in a standardized manner, paving the way for lifesaving products with improved safety and efficacy.

TCR β chain-directed bispecific antibodies for the treatment of T cell cancers

Immunotherapies such as chimeric antigen receptor (CAR) T cells and bispecific antibodies redirect healthy T cells to kill cancer cells expressing the target antigen. The pan-B cell antigen-targeting immunotherapies have been remarkably successful in treating B cell malignancies. Such therapies also result in the near-complete loss of healthy B cells, but this depletion is well tolerated by patients. Although analogous targeting of pan-T cell markers could, in theory, help control T cell cancers, the concomitant healthy T cell depletion would result in severe and unacceptable immunosuppression. Thus, therapies directed against T cell cancers require more selective targeting. Here, we describe an approach to target T cell cancers through T cell receptor (TCR) antigens. Each T cell, normal or malignant, expresses a unique TCR β chain generated from 1 of 30 TCR β chain variable gene families (TRBV1 to TRBV30). We hypothesized that bispecific antibodies targeting a single TRBV family member expressed in malignant T cells could promote killing of these cancer cells, while preserving healthy T cells that express any of the other 29 possible TRBV family members. We addressed this hypothesis by demonstrating that bispecific antibodies targeting TRBV5-5 (α-V5) or TRBV12 (α-V12) specifically lyse relevant malignant T cell lines and patient-derived T cell leukemias in vitro. Treatment with these antibodies also resulted in major tumor regressions in mouse models of human T cell cancers. This approach provides an off-the-shelf, T cell cancer selective targeting approach that preserves enough healthy T cells to maintain cellular immunity.

Obinutuzumab in Kidney Transplantation: Effect on B-cell Counts and Crossmatch Tests

BACKGROUND

Resistance to the action of rituximab (RTX) has been documented in several diseases. More recently, obinutuzumab (OBZ) has shown promise where RTX has failed in oncology and lupus nephritis. Unlike RTX, OBZ is a weak activator of complement, which may avoid the false-positive complement-dependent cytotoxicity (CDC) crossmatch tests after RTX infusions.

METHODS

The aim of this study was to explore the effect of OBZ on B-cell depletion in kidney-transplant candidates and its impact on crossmatch test results. We included 12 patients: who were either highly sensitized kidney-transplant candidates or kidney-transplant recipients presenting with antibody-mediated rejection. Six received OBZ and 6 received RTX. CD-19 counts, flow cytometry and CDC crossmatch tests were run immediately before and at 2 weeks after drug infusion.

RESULTS

OBZ reduced CD-19 counts: median reduction was 98%. B-cell CDC crossmatch test results became positive following RTX infusion but were not affected by OBZ infusion.

CONCLUSIONS

OBZ effectively depleted B-cell counts in sensitized kidney-transplant candidates and, unlike RTX, had no effect on CDC crossmatch results.

A global antiB cell strategy combining obinutuzumab and daratumumab in severe pediatric nephrotic syndrome

BACKGROUND

Steroid-sensitive nephrotic syndrome (SSNS) is, in most patients, a chronic disease with 80% experiencing at least one relapse after first flare. B cell depletion using rituximab is effective in preventing relapse in steroid-dependent (SDNS) patients but fails to maintain long-term remission following B cell recovery, possibly due to development of autoreactive long-lived plasma cells. We investigated sequential combination of antiCD20 antibody targeting all B cell subsets, and antiCD38 antibody with high plasma cell cytotoxicity in patients with uncontrolled SDNS after failure of one or several attempts at B cell depletion.

METHODS

Fourteen patients with median disease duration 7.8 years received 1000 mg/1.73 m² obinutuzumab followed by 1000 mg/1.73 m² daratumumab 2 weeks later. Oral immunosuppression was discontinued within 6 weeks, and biological monitoring performed monthly until B cell recovery.

RESULTS

Median age at treatment was 11.0 [IQR 10.4-14.4] years. B cell depletion was achieved in all patients, and B cell reconstitution occurred in all at median 9.5 months after obinutuzumab injection. After median follow-up 20.3 months (IQR 11.5-22.6), 5/14 patients relapsed including 4 within 100 days following B cell repletion. Relapse-free survival was 60% at 24 months from obinutuzumab infusion. Mild infusion reactions were reported in 3/14 patients during obinutuzumab and 4/14 during daratumumab infusions. Mild transient neutropenia (500-1000/mm³) occurred in 2/14 patients. Intravenous immunoglobulins were given to 12/14 patients due to hypogammaglobulinemia. Low IgA and IgM levels were noted in 8 and 14 patients, respectively. No severe infection was reported.

CONCLUSION

Global antiB cell strategy combining obinutuzumab and daratumumab induces prolonged peripheral B cell depletion and remission in children with difficult-to-treat SDNS.

Profiling of donor-specific immune effector signatures in response to rituximab in a human whole blood loop assay using blood from CLL patients

Rituximab is widely used in the treatment of haematological malignancies, including chronic lymphocytic leukaemia (CLL), the most common leukaemia in adults. However, some patients, especially those with high tumour burden, develop cytokine release syndrome (CRS). It is likely that more patients will develop therapy-linked CRS in the future due to the implementation of other immunotherapies, such as CAR T-cell, for many malignancies. Current methods for CRS risk assessment are limited, hence there is a need to develop new methods. To better recapitulate an in vivo setting, we implemented a unique human whole blood "loop" system to study patient-specific immune responses to rituximab in blood derived from CLL patients. Upon rituximab infusion, both complement-dependent cytotoxicity (CDC) and antibody-dependent cellular cytotoxicity (ADCC) profiles were evident in CLL patient blood, coincident with CLL cell depletion. Whereas B cell depletion is induced in healthy persons in the blood loop, only patients display B cell depletion coupled with CRS. With the exception of one donor who lacked NK cells, all other five patients displayed variable B cell depletion along with CRS profile. Additionally, inhibition of CDC or ADCC via either inhibitors or antibody Fc modification resulted in skewing of the immune killing mechanism consistent with published literature. Herein we have shown that the human whole blood loop model can be applied using blood from a specific indication to build a disease-specific CRS and immune activation profiling ex vivo system. Other therapeutic antibodies used for other indications may benefit from antibody characterization in a similar setting.

Targeting B Cells to Modify MS, NMOSD, and MOGAD: Part 1

Ocrelizumab, rituximab, ofatumumab, ublituximab, inebilizumab, and evobrutinib are immunotherapies that target various B cell-related proteins. Most of these treatments have proven efficacy in relapsing and progressive forms of MS and neuromyelitis optica spectrum disease (NMOSD), or are in advanced stages of clinical development. Currently, ocrelizumab, ofatumumab, and inebilizumab are licensed for treatment of MS and NMOSD, respectively. This review focuses on the current state of knowledge about the role of B lymphocytes in immune-mediated pathophysiology and its implications for the mode of action. To understand the significance of this breakthrough in the context of the current MS therapeutic armamentarium, this review more closely examines the clinical development of CD20 depletion and the pioneering contribution of rituximab. Phase 3 and the recently published postmarketing studies will be highlighted to better understand the relevant efficacy data and safety aspects of long-term B-cell depletion.

Monoclonal Antibodies, Bispecific Antibodies and Antibody-Drug Conjugates in Oncohematology

Background:

The therapeutic outcomes and the prognosis of patients with various hematologic malignancies are not always ideal with the current standard of care.

Objective:

The aim of this study is to analyze the results of the use of monoclonal antibodies, bispecific antibodies and antibody-drug conjugates for the therapy of malignant hemopathies.

Methods:

A mini-review was achieved using the articles published in Web of Science and PubMed between January 2017 and January 2020 and the new patents were made in this field.

Results:

Naked monoclonal antibodies have improved the therapeutic results obtained with standard of care, but they also have side effects and the use of some of them can lead to the loss of the target antigen through trogocytosis, which explains the resistance that occurs during therapy. The results obtained with naked monoclonal antibodies have been improved by a better monoclonal antibody preparation, the use of bispecific antibodies (against two antigens on the target cell surface or by binding both surface antigen on target cells and T-cell receptor complex, followed by cytotoxic T-lymphocytes activation and subsequent cytolysis of the target cell), the use of monoclonal or bispecific constructs in frontline regimens, combining immunotherapy with chemotherapy, including through the use of antibody-drug conjugates (which provides a targeted release of a chemotherapeutic agent).

Conclusion:

Immunotherapy and immuno-chemotherapy have improved the outcome of the patients with malignant hemopathies through a targeted, personalized therapy, with reduced systemic toxicity, which in some cases can even induce deep complete remissions, including minimal residual disease negativity.

Obinutuzumab-related adverse events: A systematic review and meta-analysis

Rituximab, the first anti-CD20 monoclonal antibody, has dramatically improved outcomes for patients with B-cell lymphoproliferative disorders. Obinutuzumab was developed to potentiate activity and overcome resistance to rituximab. Clinical data suggest that obinutuzumab is superior to rituximab in follicular lymphoma (FL) and chronic lymphocytic leukemia (CLL). Yet, it has increased toxicity. This systematic review and meta-analysis compiled all randomized controlled trials (RCTs) comparing obinutuzumab-based regimens with rituximab-based regimens to better assess their toxicity profile. Primary outcome was grade 3-4 infections; secondary outcomes included any adverse events (AE), grade 3-4 AE, drug discontinuation rate, and 3-years mortality. Relative risks (RRs) were estimated and pooled using a fixed-effect model, unless there was significant heterogeneity, in which case a random-effects model was used. Our comprehensive search yielded five RCTs conducted between 2009 and 2014, including 4247 patients. The trials included FL patients, CLL and diffuse large B cell lymphoma. Monoclonal antibodies were given with different chemotherapy regimens (in four trials) or as monotherapy (in one trial). The point estimate favored increase in both grade 3-4 infections rate (RR 1.17 [95% CI, 1.0-1.36]) and any AE rate (RR 1.05 [95% 1-1.1]) with obinutuzumab, although this was not statistically significant. There was a significantly increased rate of grade 3-4 AE (RR 1.15 [95% CI, 1.09-1.2]), as well as grade 3-4 toxicities including thrombocytopenia (RR 2.8 [95% CI, 1.92-4.06]), infusion related reactions (RR 2.8 [95% CI, 2.16-3.64]) and cardiac events (RR 1.65 [95% CI, 1.11-2.46]). There was no significant difference in grade 3-4 anemia and neutropenia nor in the 3-year mortality rate. The point estimate favored increase in discontinuation rate due to AE with obinutuzumab, although without statistical significance (RR 1.24 [95% CI, 1.0-1.54]). In conclusion, physicians need to weigh the clinical benefits of this agent against higher toxicity.

Casting a wider protective net: Anti-infective vaccine strategies for patients with hematologic malignancy and blood and marrow transplantation

Patients who have hematologic malignancies are at high risk for infections but vaccinations may be effective prophylaxis. The increased infection risk derives from immune defects secondary to malignancy, the classic example being CLL, and chemotherapies and immunotherapy used to treat the malignancies. Therapy of hematologic malignancies is being revolutionized by introduction of novel targeted agents and immunomodulatory medications, improving the survival of patients. At the same time those agents uniquely change the infection risk and response to immunizations. This review will summarize current vaccine recommendations for patients with hematologic malignancies including patients who undergo hematopoietic cell transplant.

The Role of Complement in the Mechanism of Action of Therapeutic Anti-Cancer mAbs

Unconjugated anti-cancer IgG1 monoclonal antibodies (mAbs) activate antibody-dependent cellular cytotoxicity (ADCC) by natural killer (NK) cells and antibody-dependent cellular phagocytosis (ADCP) by macrophages, and these activities are thought to be important mechanisms of action for many of these mAbs in vivo. Several mAbs also activate the classical complement pathway and promote complement-dependent cytotoxicity (CDC), although with very different levels of efficacy, depending on the mAb, the target antigen, and the tumor type. Recent studies have unraveled the various structural factors that define why some IgG1 mAbs are strong mediators of CDC, whereas others are not. The role of complement activation and membrane inhibitors expressed by tumor cells, most notably CD55 and CD59, has also been quite extensively studied, but how much these affect the resistance of tumors in vivo to IgG1 therapeutic mAbs still remains incompletely understood. Recent studies have demonstrated that complement activation has multiple effects beyond target cell lysis, affecting both innate and adaptive immunity mediated by soluble complement fragments, such as C3a and C5a, and by stimulating complement receptors expressed by immune cells, including NK cells, neutrophils, macrophages, T cells, and dendritic cells. Complement activation can enhance ADCC and ADCP and may contribute to the vaccine effect of mAbs. These different aspects of complement are also briefly reviewed in the specific context of FDA-approved therapeutic anti-cancer IgG1 mAbs.

Humanized anti CD-20 as an alternative in chronic management of relapsing thrombotic thrombocytopenic microangiopathy resistant to rituximab due to anti chimeric antibody

Acquired Immune thrombotic thrombocytopenic purpura (iTTP) is considered among clinical situations that needs not only urgent treatment in acute setting but also long term management to prevent relapses. Important progresses have been made in management of these patients that are definitely associated with reduced mortality and relapse rate. However, there are still noticeable percentage of patients that may relapse despite application of modern treatment strategies including preemptive rituximab infusions. Hereby, we share our experience concerning a frequently relapsing iTTP due to development of anti-rituximab antibody. In our case administration of obinutuzumab, a humanized type II anti CD-20 antibody was associated with complete peripheral blood B cell depletion and increasing plasma ADAMTS-13 activity.

The Pharmacogenetics of Rituximab: Potential Implications for Anti-CD20 Therapies in Multiple Sclerosis

There are a broad range of disease-modifying therapies (DMTs) available in relapsing-remitting multiple sclerosis (RRMS), but limited biomarkers exist to personalise DMT choice. All DMTs, including monoclonal antibodies such as rituximab and ocrelizumab, are effective in preventing relapses and preserving neurological function in MS. However, each agent harbours its own risk of therapeutic failure or adverse events. Pharmacogenetics, the study of the effects of genetic variation on therapeutic response or adverse events, could improve the precision of DMT selection. Pharmacogenetic studies of rituximab in MS patients are lacking, but pharmacogenetic markers in other rituximab-treated autoimmune conditions have been identified. This review will outline the wider implications of pharmacogenetics and the mechanisms of anti-CD20 agents in MS. We explore the non-MS rituximab literature to characterise pharmacogenetic variants that could be of prognostic relevance in those receiving rituximab, ocrelizumab or other monoclonal antibodies for MS.

Analytical comparability study of anti-CD20 monoclonal antibodies rituximab and obinutuzumab using a stability-indicating orthogonal testing protocol: Effect of structural optimization and glycoengineering

Glycoengineering and biosimilarity are the key factors for growing, promising and progressive approaches in monoclonal antibodies development. In this study, the physicochemical stability of anti-CD20 rituximab (RTX); originator and biosimilar was compared to its glycoengineered humanized version; obinutuzumab (OBZ). An orthogonal stability-indicating protocol using a set of validated bioanalytical techniques; size exclusion high performance liquid chromatography (SE-HPLC), reversed phase liquid chromatography (RP-HPLC), quantitative gel electrophoresis by TapeStation, receptor binding assay and dynamic light scattering (DLS) was used to investigate the effect of different stress factors on the pattern and kinetics of degradation. SE-HPLC results supported with spectral purity showed similar degradation extent with a different pattern of degradation between RTX and OBZ. A lower tendency to form degraded fragments and a relatively higher favorability for degradation through aggregate formation has been revealed in case of OBZ. Results were in agreement with those of DLS and receptor binding assay which showed specificity to the intact antibodies in the presence of their degradation products. Furthermore, results were additionally confirmed through denaturing quantitative gel electrophoresis which suggested reducible covalent bonds as the mechanism for aggregates formation. RP-HPLC results showed two oxidized forms via excessive oxidation of RTX and OBZ with nearly the same degradation percent. Comparability data of RTX and OBZ using the applied methodologies showed that although glycoengineering; carried out to enhance the therapeutic and biological activity of OBZ altered the pattern of degradation but did not significantly affect the overall stability. Results showed also consistent stability profile between the biosimilar and its originator RTX products.

Noninvasive Evaluation of CD20 Expression Using 64Cu-Labeled F(ab')2 Fragments of Obinutuzumab in Lymphoma

CD20-overexpressed non-Hodgkin lymphoma typically indicates progressive malignancy. Obinutuzumab is a next-generation Food and Drug Administration-approved humanized monoclonal antibody that targets CD20. Previous studies with ⁸⁹Zr-labeled obinutuzumab have successfully imaged CD20 in vivo. However, delayed tumor uptake and increased radioactive exposure caused by long blood circulation limit its clinical translation. This study aimed to develop ⁶⁴Cu-labeled F(ab')₂ fragments of obinutuzumab for imaging CD20 in lymphoma xenograft tumor models. Methods: F(ab')₂ fragments were produced from obinutuzumab using an IgG-degrading enzyme of Streptococcus pyogenes (IdeS) enzyme and purified with protein A beads. Sodium dodecyl sulfate polyacrylamide gel electrophoresis and high-performance liquid chromatography were performed to evaluate the products and their stability. F(ab')₂ products were conjugated with p-SCN-Bn-NOTA (NOTA) for ⁶⁴Cu radiolabeling. Western blotting was performed to screen the CD20 expression levels of lymphoma cells. Enzyme-linked immunosorbent assay, flow cytometry, and confocal imaging were used to test the binding affinity in vitro. Serial PET imaging and biodistribution studies in subcutaneous lymphoma-bearing mice were performed using ⁶⁴Cu-NOTA-F(ab')₂-obinutuzumab or ⁶⁴Cu-NOTA-F(ab')₂-IgG. Results: F(ab')₂-obinutuzumab and F(ab')₂-IgG produced by the IdeS digestion system were confirmed with sodium dodecyl sulfate polyacrylamide gel electrophoresis and high-performance liquid chromatography. The radiochemical purity of ⁶⁴Cu-labeled F(ab')₂ fragments was no less than 98%, and the specific activity was 56.3 ± 7.9 MBq/mg (n = 6). Among the 5 lymphoma cell lines, Ramos showed the strongest expression of CD20, and CLL-155 showed the lowest, as confirmed by enzyme-linked immunosorbent assay, flow cytometry, and confocal imaging. PET imaging revealed rapid and sustained tumor uptake of ⁶⁴Cu-NOTA-F(ab')₂-obinutuzumab in Ramos tumor-bearing mice. The peak tumor uptake (9.08 ± 1.67 percentage injected dose per gram of tissue [%ID/g]) in the Ramos model was significantly higher than that in the CCL-155 model (2.78 ± 0.62 %ID/g) or the ⁶⁴Cu-NOTA-F(ab')₂-IgG control (1.93 ± 0.26 %ID/g, n = 4, P < 0.001). The tumor-to-blood and tumor-to-muscle ratios were 7.3 ± 1.6 and 21.9 ± 9.0, respectively, at 48 h after injection in the ⁶⁴Cu-NOTA-F(ab')₂-obinutuzumab group. Of the measured off-target organs, the kidneys showed the highest uptake. Ex vivo immunofluorescent staining verified the differential CD20 expression in the Ramos and CCL-155 tumor models. Conclusion: This study demonstrated that ⁶⁴Cu-NOTA-F(ab')₂-obinutuzumab had a rapid and sustained tumor uptake in CD20-positive lymphoma with high contrast, which could enable noninvasive evaluation of CD20 levels in the clinic.

A review of advances in the understanding of lupus nephritis pathogenesis as a basis for emerging therapies

Lupus nephritis is an important cause of both acute kidney injury and chronic kidney disease that can result in end-stage renal disease. Its pathogenic mechanisms are characterized by aberrant activation of both innate and adaptive immune responses, dysregulation of inflammatory signaling pathways, and increased cytokine production. Treatment of lupus nephritis remains a challenging issue in the management of systemic lupus erythematosus since the clinical presentation, response to treatment, and prognosis all vary considerably between patients and are influenced by ethnicity, gender, the degree of chronic kidney damage, pharmacogenomics, and non-immunological modulating factors. Elucidation of the various immunopathogenic pathways in lupus nephritis has resulted in the development of novel therapies, including biologics that target specific antigens on B lymphocytes to achieve B cell depletion, agents that modulate B cell proliferation and development, drugs that block co-stimulatory pathways, drugs that target T lymphocytes primarily, and therapies that target complement activation, signaling pathways, pro-inflammatory cytokines, and neutrophil extracellular traps. This review will discuss recent advances in the understanding of disease pathogenesis in lupus nephritis in the context of potential emerging therapies.

Novel Therapies Potentially Available for Pediatric B-Cell Non-Hodgkin Lymphoma

Burkitt lymphoma, diffuse large B-cell lymphoma (DLBCL), and primary mediastinal B-cell lymphoma are the most common aggressive pediatric mature B-cell non-Hodgkin lymphomas (B-NHLs). Despite excellent survival with current chemotherapy regimens, therapy for Burkitt lymphoma and DLBCL has a high incidence of short- and long-term toxicities. Patients who experience relapse generally have a very poor prognosis. Therefore, novel approaches using targeted therapies to reduce toxicities and improve outcomes in the relapse setting are needed. The addition of rituximab, a monoclonal antibody against CD20, to upfront therapy has improved survival outcomes for high-risk patients and may allow decreased total chemotherapy in those with low-risk disease. Antibody-drug conjugates have been combined with chemotherapy in relapsed/refractory (R/R) NHL, and multiple antibody-drug conjugates are in development. Additionally, bispecific T-cell-engaging antibody constructs and autologous CAR T-cells have been successful in the treatment of R/R acute leukemias and are now being applied to R/R B-NHL with some successes. PD-L1 and PD-L2 on tumor cells can be targeted with checkpoint inhibitors, which restore T-cell-mediated immunity and antitumor responses and can be added to conventional chemotherapy and immune-directed therapies to augment responses. Lastly, trials of small molecule inhibitors targeting cell signaling pathways in NHL subtypes are underway. This article reviews many of the targeted therapies under development that could be considered for future trials in R/R pediatric mature B-NHL.

Initial Treatment of High Tumor Burden Follicular Lymphoma

Follicular lymphoma is the most common indolent B-cell lymphoma, with most patients presenting with advanced-stage disease. Patients who are symptomatic or otherwise meet the criteria for high tumor burden merit immediate intervention with combination immunochemotherapy, although more recently, "chemotherapy-free" approaches including novel therapies have shown benefit in this treatment-naïve population. In this review, the authors critically appraise the criteria for high tumor burden, the various options available for initial therapy, and the optimal post-treatment surveillance strategies.