Monoclonal antibody therapy for B-cell non-Hodgkin's lymphoma

Adverse Reactions in Relapsed/Refractory B-Cell Lymphoma Administered with Chimeric Antigen Receptor T Cell Alone or in Combination with Autologous Stem Cell Transplantation

(1) Background: The combination of CAR-T with ASCT has been observed to enhance the efficacy of CAR-T cell therapy. However, the impact of this combination on adverse reactions is still uncertain. (2) Methods: Between January 2019 and February 2023, 292 patients diagnosed with r/r B-cell lymphoma received either CAR-T therapy alone or in combination with ASCT at our institution. We evaluated the incidence of CRS and CRES and utilized a logistic regression model to identify factors contributing to severe CRS (grade 3-4) and CRES (grade 3-4). (3) Results: The overall incidence of CRS and CRES was 78.9% and 8.2% in 147 patients receiving CAR-T alone, and 95.9% and 15.2% in 145 patients receiving CAR-T combined with ASCT, respectively. The incidence of overall CRS (p < 0.0001) and mild CRS (grade 1-2) (p = 0.021) was elevated in the ASCT combined with CAR-T group. No significant difference was observed in severe CRS and CRES between the groups. Among the 26 cases of lymphoma involving the central nervous system (CNS), 96.2% (25/26) developed CRS (15.4% grade 3-4), and 34.6% (9/26) manifested CRES (7.7% grade 3-4). Female patients had a lower incidence of severe CRS but a higher incidence of severe CRES. Lymphomas with CNS involvement demonstrated a higher risk of CRES compared to those without central involvement. (4) Conclusions: The combination of ASCT with CAR-T demonstrated a preferable option in r/r B-cell lymphoma without an increased incidence of severe CRS and CRES.

Recent preclinical and clinical advances in radioimmunotherapy for non-Hodgkin's lymphoma

Radioimmunotherapy (RIT) is a therapy that combines a radioactive nucleotide with a monoclonal antibody (mAb). RIT enhances the therapeutic effect of mAb and reduces toxicity compared with conventional treatment. The purpose of this review is to summarize the current progress of RIT for treating non-Hodgkin's lymphoma (NHL) based on recent preclinical and clinical studies. The efficacy of RIT targeting the B-lymphocyte antigen cluster of differentiation 20 (CD20) has been demonstrated in clinical trials. Two radioimmunoconjugates targeting CD20, yttrium-90 (90Y)-ibritumomab-tiuxetan (Zevalin) and iodine-131 (131I)-tositumomab (Bexxar), have been approved in the USA Food and Drug Administration (FDA) for treating relapsed/refractory indolent or transformed NHL in 2002 and 2003, respectively. Although these two radioimmunoconjugates are effective and least toxic, they have not achieved popularity due to increasing access to novel therapies and the complexity of their delivery process. RIT is constantly evolving with the identification of novel targets and novel therapeutic strategies using newer radionuclides such as alpha-particle isotopes. Alpha-particles show very short path lengths and high linear energy transfer. These characteristics provide increased tumor cell-killing activities and reduced non-specific bystander responses on normal tissue. This review also discusses reviewed pre-targeted RIT (PRIT) and immuno-positron emission tomography (PET). PRIT potentially increases the dose of radionuclide delivered to tumors while toxicities to normal tissues are limited. Immuno-PET is a molecular imaging tracer that combines the high sensitivity of PET with the specific targeting capability of mAb. Immuno-PET strategies targeting CD20 and other antigens are currently being developed. The theragnostic approach by immuno-PET will be useful in monitoring the treatment response.

Anti-CD19/CD8 bispecific T cell engager for the potential treatment of B cell malignancies

The administration of blinatumomab was accompanied by several adverse effects, including activation of regulatory T-cells and cytokine storm. The objective of this study was to produce and evaluate a novel αCD8/CD19 BiTE (αCD8/CD19) with the potency to directly target CD8+T-cells. In-silico studies were utilized for determining proper folding, receptor binding, and structural stability of αCD8/CD19 protein. Western blotting and indirect surface staining were used to evaluate the size accuracy and binding potency of the purified protein. Functionality was assessed for granzyme B production, cytotoxicity, and proliferation. TheαCD8/CD19recombinant protein was produced in the CHO-K1 cell line with a final concentration of 1.94 mg/l. The αCD8/CD19 bound to CD8+and CD19+cell lines and induced significant granzyme B production, cytotoxic activity and proliferation potential in the presence of IL-2 and tumor target cells. The maximum CD8+T-cell biological activity was observed on the 10th day with 10:1 effector-to-target ratio.

Trends in non-Hodgkin lymphoma mortality rate in Japan and the United States: A population-based study

Characterizing trends in mortality rates with consideration of trends in incidence rates at the population level could help identify unmet needs in public health and provide essential indicators of cancer control. In the late 20th century, the arrival of the first molecular targeted agent, rituximab, for non-Hodgkin lymphoma (NHL) led to a paradigm shift in NHL treatment. However, the public health impact of this arrival has not been fully clarified. Here, we evaluated trends in the mortality and incidence rates of NHL in Japan and the United States. Age-standardized rates of mortality reversed after the introduction of rituximab, around 2000, beginning to decline significantly with annual percent changes (95% confidence interval) of -2.6% (-3.6% to -1.6%) in Japan and - 3.9% (-4.2% to -3.5%) in the United States. Despite an increase in incidence, the mortality in all age groups weakened the upward trends or decreased in both countries. From a long-term perspective, the trends in mortality rates differed between the countries. In the United States, the mortality rate has declined continuously since the introduction of rituximab, with a declining incidence rate. In contrast, in Japan, the mortality rate stopped declining and the incidence rate increased remarkably. The introduction of rituximab has had a substantial impact at the population level across a wide range of individuals. To reduce the disease burden in terms of mortality, elucidating risk factors that lead to a decreasing incidence rate is warranted for NHL, as well as further development of novel treatments.

Rationale, current state and opportunities in combining biologic disease modifying antirheumatic drugs in rheumatoid and psoriatic arthritis

The advent of biologic disease modifying antirheumatic drugs (bDMARDs) has considerably improved patient outcomes in inflammatory arthritis. However, not all patients reach the state of remission, as disease can be resistant even to single cytokine inhibition by bDMARDs. Simultaneous or sequential inhibition of multiple cytokines may be considered in situations where disease control is not adequate under singular inhibition of cytokines. Although there have been some disappointing experiences in the past with combination of bDMARDs, the ongoing improvement of our understanding about inflammatory pathways and the overall better safety understanding of bDMARDs seem to make new biologic treatment combinations possible. This review covers the rationale and current evidence for bDMARDs combination in inflammatory arthritis.

Design, synthesis, and evaluation of BTK-targeting PROTACs with optimized bioavailability in vitro and in vivo

Ibrutinib is a first-line drug for the treatment of B-cell malignancies. BTKC481S mutation has led to drug resistance during clinical application. Herein, a novel BTK-targeting PROTAC molecule with better solubility and bioavailability was developed. Compound 15-271 has better solubility than ibrutinib and some reported BTK PROTACs. 15-271 has better liver microsomal stability than its analogues in multiple species. More importantly, 15-271 has a longer half-life and better bioavailability in vivo. The development strategy of compound 15-271 can be a general procedure for the optimization of other PROTACs.

Vitamin D Enhances Immune Effector Pathways of NK Cells Thus Providing a Mechanistic Explanation for the Increased Effectiveness of Therapeutic Monoclonal Antibodies

Patients with diffuse large cell lymphoma who have an adequate vitamin D supply derive significantly more benefit from immuno-chemotherapy with rituximab than patients with vitamin D deficiency; this is especially true for female patients. We have already been able to show that vitamin D increases the antibody-dependent cytotoxicity (ADCC) of NK cells in a sex-dependent manner, but it is unclear how vitamin D makes NK cells more efficient.

METHODS

Healthy individuals with vitamin D deficiency were supplemented with vitamin D to sufficient levels. NK cells were isolated from blood samples before and after vitamin D saturation. For transcriptome analysis, we used the Affymetrix Gene-Chip 2.0™. Gene expression analysis as well as supervised and unsupervised pathway analysis were performed.

RESULTS

Among others the "NK cell-associated cytotoxicity pathway" increased after vitamin D substitution. Five IFN-α subtypes (2, 4, 6, 7 and 10) and IFN-κ were more highly expressed and are mainly responsible in these pathways. In contrast, the pathway "interferon-gamma response", as well as other sets in cytokine production and chemotaxis showed a reduction. Toll-like receptor genes (TLR-8, TLR-7, TLR-2) were downregulated and, therefore, are responsible for the decline of these pathways. The same could be shown for the "ubiquitin-ligase" pathway.

CONCLUSIONS

Increased expression of several IFN-α subtypes may explain the increased ADCC of NK cells in vitamin D-replenished and otherwise healthy subjects. Other regulators of interferon production and ADCC are compensatory upregulated in compensation, such as Toll-like receptors and those of the ubiquitin ligase, and normalize after vitamin D substitution.

Risk of Infections Secondary to the Use of Targeted Therapies in Hematological Malignancies

Concurrent infections in hematological malignancies (HM) are major contributors to adverse clinical outcomes, including prolonged hospitalization and reduced life expectancy. Individuals diagnosed with HM are particularly susceptible to infectious pathogens due to immunosuppression, which can either be inherent to the hematological disorder or induced by specific therapeutic strategies. Over the years, the treatment paradigm for HM has witnessed a tremendous shift, from broad-spectrum treatment approaches to more specific targeted therapies. At present, the therapeutic landscape of HM is constantly evolving due to the advent of novel targeted therapies and the enhanced utilization of these agents for treatment purposes. By initiating unique molecular pathways, these agents hinder the proliferation of malignant cells, consequently affecting innate and adaptive immunity, which increases the risk of infectious complications. Due to the complexity of novel targeted therapies and their associated risks of infection, it often becomes a daunting task for physicians to maintain updated knowledge in their clinical practice. The situation is further aggravated by the fact that most of the initial clinical trials on targeted therapies provide inadequate information to determine the associated risk of infection. In such a scenario, a cumulative body of evidence is paramount in guiding clinicians regarding the infectious complications that can arise following targeted therapies. In this review, I summarize the recent knowledge on infectious complications arising in the context of targeted therapies for HM.

Immunotherapy for Hodgkin lymphoma: From monoclonal antibodies to chimeric antigen receptor T-cell therapy

Although up to 80 % of Hodgkin lymphoma (HL) patients are cured with first-line therapy, relapsed/refractory HL remains a major clinical obstacle and is fatal for patients who are not candidates for autologous stem cell transplantation (ASCT) or relapse after treatment. Several immune-based approaches have been investigated in recent years with the aim of exerting a possible antitumor effect through the immune system response to cancer cells. Clinical studies on novel agents, including brentuximab vedotin (BV) and PD-1 inhibitors, have successfully demonstrated their effectiveness in relapsed disease after ASCT. Additionally, studies examining combination strategies with the goal of reducing the risk of relapse and chemotherapy-related toxicity have showed encouraging results, mainly in untreated early unfavorable or advanced stage classical HL (cHL). Other non-approved immunotherapies such as camidanlumab tesirine, bispecific CD30/CD16A antibody, and CD30 chimeric antigen receptor (CAR) T-cell therapy are promising approaches that may reinforce the therapeutic arsenal available to patients.

Patients with indolent lymphomas are at high risk of infections: experience from a German outpatient clinic

BACKGROUND

Patients with indolent B-cell non-Hodgkin lymphomas (B-NHLs) have an increased risk of infections which is caused by pathomechanisms of the diseases itself but also as a result of anti-tumor therapy. Especially the effects of anti-CD20 antibodies are well understood as these lead to decreased antibody production. Most studies regarding immunodeficiency in B-NHLs were conducted with multiple myeloma and chronic lymphocytic leukemia patients. As these studies not always represent the general population we collected and analyzed real world data from patients with indolent lymphomas and a control group (CG).

RESULTS

Patients with B-NHLs undergoing therapy or who were regularly monitored in a watch and wait approach had, over the time of one year, an increased rate of infections compared to the CG of 145 healthy volunteers (mean: 11.66 vs. 7.13 infections per 1000 days). Consistent with this finding B-NHL patients received more antibiotic treatment (mean: 11.17 vs. 6.27 days) and were more often hospitalized than persons from the CG (mean: 5.19 vs. 0.99 days per 1000 days). Lymphoma patients without immunodeficiency had a lower infection rate than patients with non-symptomatic and symptomatic immunodeficiency (mean: 10.91 vs. 12.07 and 12.36 per 1000 days). The number of infections differed statistically significant for the subgroups and CG (7.13 per 1000 days). Patients with symptomatic immunodeficiency were mostly treated with regular immunoglobulin substitutions and infection rates were comparable to those of patients with asymptomatic immunodeficiency.

CONCLUSIONS

Our data suggest the use of an approach with regular immune monitoring including the measurement of immunoglobulin levels and regular appointments for clinical assessment of all indolent lymphoma patients in order to identify patients with increased risk of infections. It also raises the question if patients with immunodeficiency should be treated more often with regular immunoglobulin substitution, but so far more studies are necessary to answer this question.

Cysteine-specific 89Zr-labeled anti-CD25 IgG allows immuno-PET imaging of interleukin-2 receptor-α on T cell lymphomas

Introduction

Positron emission tomography (PET) using radiolabeled Abs as imaging tracer is called immuno-PET. Immuno-PET can verify therapeutic Ab delivery and can noninvasively quantify global levels of target expression in tumors of living subjects. The interleukin-2 receptor α chain (IL-2Rα; CD25) is a promising target for immune therapy and radioimmunotherapy of lymphomas. Immuno-PET could facilitate this approach by visualizing CD25 expression in vivo.

Methods

We prepared ⁸⁹Zr-anti-CD25 IgG specifically labeled to sulfhydryl moieties by maleimide-deferoxamine conjugation.

Results and Discussion

CD25(+) SUDHL1 human T-cell lymphoma cells showed high anti-human ⁸⁹Zr-CD25 IgG binding that reached 32-fold of that of CD25(-) human lymphoma cells and was completely blocked by excess unlabeled Ab. In SUDHL1 tumor-bearing nude mice, pharmacokinetic studies demonstrated exponential reductions of whole blood and plasma activity following intravenous ⁸⁹Zr-anti-CD25 IgG injection, with half-lives of 26.0 and 23.3 h, respectively. SUDHL1 tumor uptake of ⁸⁹Zr-CD25 IgG was lower per weight in larger tumors, but blood activity did not correlate with tumor size or blood level of human CD25, indicating minimal influence by circulating soluble CD25 protein secreted from the lymphoma cells. ⁸⁹Zr-CD25 IgG PET allowed high-contrast SUDHL1 lymphoma visualization at five days. Biodistribution studies confirmed high tumor ⁸⁹Zr-CD25 IgG uptake (8.7 ± 0.9%ID/g) that was greater than blood (5.2 ± 1.6%ID/g) and organ uptakes (0.7 to 3.5%ID/g). Tumor CD25-specific targeting was confirmed by suppression of tumor uptake to 4.3 ± 0.2%ID by excess unlabeled CD25 IgG, as well as by low tumor uptake of ⁸⁹Zr-labeled IgG2a isotype control Ab (3.6 ± 0.9%ID). Unlike CD25(+) lymphocytes from mouse thymus that showed specific uptake of anti-mouse ⁸⁹Zr-CD25 IgG, EL4 mouse lymphoma cells had low CD25 expression and showed low uptake. In immunocompetent mice bearing EL4 tumors, anti-mouse ⁸⁹Zr-CD25 IgG displayed low uptakes in normal organs as well as in the tumor. Furthermore, the biodistribution was not influenced by Ab blocking, indicating that specific uptake in nontumor tissues was minimal. ⁸⁹Zr-CD25 IgG immuno-PET may thus be useful for imaging of T-cell lymphomas and noninvasive assessment of CD25 expression on target cells in vivo.

Computational and Experimental Evaluation of Linker Peptides and Thioredoxin Fusion Tag in CD20-rituximab Specific Interactions

Background

Overexpression of CD20 protein on the surface of B cells in lymphoma can be targeted by several anti-CD20 molecules. The development of accessible interactive epitopes is more favorable than the full-length transmembrane CD20 in the affinity assessment of anti-CD20 monoclonal antibodies (mAbs).

Methods

The sequence of these epitopes was extracted, and the effects of different linker peptides and the location of histidine (His)-tag were computationally analyzed. The impact of thioredoxin (Trx)-tag on the folding of the selected construct and its interaction with rituximab was further investigated. The two final expression cassettes were expressed in Escherichia coli after optimization of culture conditions for incubation temperature, post-induction time, optical density at the induction time, and concentration of the inducer. ELISA evaluated the binding affinity of rituximab towards the recombinant proteins.

Results

By homology modeling studies, C-terminal His-tagged structures represented more desirable folded structures. Validation of the models revealed that CD20 extracellular domain linked by the G₄S polypeptide had better stereochemical quality and structural compatibility. It was selected due to its more effective interaction with rituximab showing the highest dissociation constant of 5.8E-09M, which improved after the fusion of Trx-tag (7.1E-10M). The most influential parameters in the expression of the two selected proteins were post-induction temperature and optical density at the induction time. Homemade ELISA assays revealed a slightly higher affinity of rituximab towards the Trx-CD20 protein than the CD20/G₄S molecule.

Conclusions

Experimental in vitro studies confirmed the computationally calculated affinity of rituximab towards the two designed CD20 constructs. Also, the cell-based binding assessment of anti-CD20 mAbs could be substituted by the engineered extracellular domain of human CD20 protein.

A β-glucan from Aureobasidium pullulans enhanced the antitumor effect with rituximab against SU-DHL-8

β-Glucans affect the immune system and have antitumor activity; therefore, they are being investigated as immunomodulators and chemotherapeutic adjuvants. In this study, we investigated a specific β-glucan, exopolysaccharide (EPS-1) derived from Aureobasidium pullulans (CGMCC 20363), to investigate its impact on the efficacy of rituximab against diffuse large B cell lymphoma (SU-DHL-8 cells) in vitro and in vivo. The results show that compared to rituximab alone, EPS-1 enhanced the inhibition of SU-DHL-8, had antitumor effects in vivo, and improved the response of the immune system of the host. RNA sequencing results reveal that EPS-1 had a chemotactic effect on T cells through the JAK-STAT signaling pathway and recruited immune cells into tumor tissues. EPS-1 also played an antitumor role through the mitochondrial and death receptor Fas-related apoptotic pathways. In summary, EPS-1 may be an effective adjuvant to treat diffuse large B cell lymphoma in combination with rituximab.

Immuno-PET Imaging and Radioimmunotherapy of Lymphomas

Monoclonal antibodies (Ab) have revolutionized the management of lymphomas, the most common hematologic malignancy in adults. Indeed, incorporation of rituximab into the regimen for indolent non-Hodgkin's lymphomas (NHLs) has dramatically improved treatment response and disease outcome. Yet, newer Ab therapeutics against promising antigen targets need to be developed to treat refractory or relapsed patients. Treatment efficacy can be further enhanced by conjugating toxic molecules to the Abs. Radioimmunotherapy (RIT) harnesses Abs as vehicles for targeted delivery of therapeutic radionuclide payloads for direct killing of targeted tumor cells. Positron emission tomography (PET) with radiolabeled Abs (called immuno-PET) can facilitate the development of new Ab therapeutics and RIT by providing pharmacokinetic and pharmacodynamic information and by quantifying tumor antigen level relevant for treatment decision. Immuno-PET has recently gravitated toward labeling Abs with ⁸⁹Zr, a radiometal with a 3.3 day half-life that is trapped following Ab internalization and thus provides high-resolution PET images with excellent contrast. Immuno-PET methods against major lymphoma antigens including CD20 and other promising targets are currently under development. With continued improvements, immuno-PET has the potential to be used in lymphoma management as an imaging biomarker for patient selection and assessment of treatment response.

The SUMOylation inhibitor subasumstat potentiates rituximab activity by IFN1-dependent macrophage and NK cell stimulation

Small ubiquitin-like modifier (SUMO) is a member of a ubiquitin-like protein superfamily. SUMOylation is a reversible posttranslational modification that has been implicated in the regulation of various cellular processes including inflammatory responses and expression of type 1 interferons (IFN1). In this report, we have explored the activity of the selective small molecule SUMOylation inhibitor subasumstat (TAK-981) in promoting antitumor innate immune responses. We demonstrate that treatment with TAK-981 results in IFN1-dependent macrophage and natural killer (NK) cell activation, promoting macrophage phagocytosis and NK cell cytotoxicity in ex vivo assays. Furthermore, pretreatment with TAK-981 enhanced macrophage phagocytosis or NK cell cytotoxicity against CD20+ target cells in combination with the anti-CD20 antibody rituximab. In vivo studies demonstrated enhanced antitumor activity of TAK-981 and rituximab in CD20+ lymphoma xenograft models. Combination of TAK-981 with anti-CD38 antibody daratumumab also resulted in enhanced antitumor activity. TAK-981 is currently being studied in phase 1 clinical trials (#NCT03648372, #NCT04074330, #NCT04776018, and #NCT04381650; www.clinicaltrials.gov) for the treatment of patients with lymphomas and solid tumors.

Benefits of Chimeric Antigen Receptor T-Cell Therapy for B-Cell Lymphoma

Objective: The aim was to study the benefits and risks of anti-CD19 chimeric antigen receptor (CAR) T-cells in adults with B-cell lymphoma.

Methods: From October 2015 to October 2021, we treated five patients with B-cell lymphoma, comprising two with mantle cell lymphoma, one case of Burkitt lymphoma, one case of diffuse large B-cell lymphoma, and one case of chronic lymphocytic leukemia/small lymphocytic lymphoma. The patients were given the FC regimen 5 days before the infusion of anti-CD19 CAR T-cells. The median total number of CAR T-cells infusions was 350*10^6 (88*10^6–585*10^6).

Results: 1) Patients who received CAR T-cell induction therapy achieved complete remission (CR) in Case 1 and Case 3 and partial remission (PR) in Case 2. Case 3’s ATM and D13S25 gene deletions were negative 42 days after CAR T-cell therapy, and molecular biology CR (mCR) and minimal residual disease (MRD) were negative for 5 years and 6 months. The patient in Case 3 was cured. 2) Case 4 patient’s TP53 gene mutation became negative 1 month after CAR T-cell therapy. MRD was negative after CAR T-cell therapy at 41 and 42 months in Cases 4 and 5, respectively. 3) Case 1∼Case 3 patients developed cytokine release syndrome (CRS) without encephalopathy syndrome, accompanied with serious adverse events. CRS can be effectively managed with tocilizumab, etanercept, glucocorticoids, and plasmapheresis.

Conclusion: Anti-CD19 CAR T-cell therapy is effective in treating relapsed/refractory B-cell lymphoma, and the side effects of CAR T-cell therapy can be properly managed. CAR T-cell therapy has high efficacy and presented no side effects in the treatment of MRD in B-cell lymphoma (NCT03685786, NCT02456350).

Prolactin receptor signaling: A novel target for cancer treatment - Exploring anti-PRLR signaling strategies

Prolactin (PRL) is a peptide hormone mainly secreted from the anterior pituitary gland. PRL is reported to play a role in pregnancy, mammary gland development, immune modulation, reproduction, and differentiation of islet cells. PRL binds to its receptor PRLR, which belongs to a superfamily of the class I cytokine receptor that has no intrinsic kinase activity. In canonical signaling, PRL binding to PRLR induces downstream signaling including JAK-STAT, AKT and MAPK pathways. This leads to increased cell proliferation, stemness, migration, apoptosis inhibition, and resistance to chemotherapy. PRL-signaling is upregulated in numerous hormone-dependent cancers including breast, prostate, ovarian, and endometrial cancer. However, more recently, the pathway has been reported to play a tumor-promoting role in other cancer types such as colon, pancreas, and hepatocellular cancers. Hence, the signaling pathway is an attractive target for drug development with blockade of the receptor being a potential therapeutic approach. Different strategies have been developed to target this receptor including modification of PRL peptides (Del1-9-G129R-hPRL, G129R-Prl), growth hormone receptor/prolactin receptor bispecific antibody antagonist, neutralizing antibody LFA102, an antibody-drug conjugate (ABBV-176) of the humanized antibody h16f (PR-1594804) and pyrrolobenzodiazepine dimer, a bispecific antibody targeting both PRLR and CD3, an in vivo half-life extended fusion protein containing PRLR antagonist PrlRA and albumin binding domain. There have also been attempts to discover and develop small molecular inhibitors targeting PRLR. Recently, using structure-based virtual screening, we identified a few antipsychotic drugs including penfluridol as a molecule that inhibits PRL-signaling to inhibit PDAC tumor progression. In this review, we will summarize the recent advances in the biology of this receptor in cancer and give an account of PRLR antagonist development for the treatment of cancer.

Remodeling the Tumor Myeloid Landscape to Enhance Antitumor Antibody Immunotherapies

Among the diverse tumor resident immune cell types, tumor-associated macrophages (TAMs) are often the most abundant, possess an anti-inflammatory phenotype, orchestrate tumor immune evasion and are frequently associated with poor prognosis. However, TAMs can also be harnessed to destroy antibody-opsonized tumor cells through the process of antibody-dependent cellular phagocytosis (ADCP). Clinically important tumor-targeting monoclonal antibodies (mAb) such as Rituximab, Herceptin and Cetuximab, function, at least in part, by inducing macrophages to eliminate tumor cells via ADCP. For IgG mAb, this is mediated by antibody-binding activating Fc gamma receptors (FcγR), with resultant phagocytic activity impacted by the level of co-engagement with the single inhibitory FcγRIIb. Approaches to enhance ADCP in the tumor microenvironment include the repolarization of TAMs to proinflammatory phenotypes or the direct augmentation of ADCP by targeting so-called 'phagocytosis checkpoints'. Here we review the most promising new strategies targeting the cell surface molecules present on TAMs, which include the inhibition of 'don't eat me signals' or targeting immunostimulatory pathways with agonistic mAb and small molecules to augment tumor-targeting mAb immunotherapies and overcome therapeutic resistance.

Strategies to Optimise Oncolytic Viral Therapies: The Role of Natural Killer Cells

Oncolytic viruses (OVs) are an emerging class of anti-cancer agents that replicate selectively within malignant cells and generate potent immune responses. Their potential efficacy has been shown in clinical trials, with talimogene laherparepvec (T-VEC or IMLYGIC®) now approved both in the United States and Europe. In healthy individuals, NK cells provide effective surveillance against cancer and viral infections. In oncolytic viral therapy, NK cells may render OV ineffective by rapid elimination of the propagating virus but could also improve therapeutic efficacy by preferential killing of OV-infected malignant cells. Existing evidence suggests that the overall effect of NK cells against OV is context dependent. In the past decade, the understanding of cancer and OV biology has improved significantly, which helped refine this class of treatments in early-phase clinical trials. In this review, we summarised different strategies that have been evaluated to modulate NK activities for improving OV therapeutic benefits. Further development of OVs will require a systematic approach to overcome the challenges of the production and delivery of complex gene and cell-based therapies in clinical settings.

Blocking FcγRIIB in Smooth Muscle Cells Reduces Hypertension

[Figure: see text].

Phase I Trial of N-803, an IL15 Receptor Agonist, with Rituximab in Patients with Indolent Non-Hodgkin Lymphoma

PURPOSE

N-803 is an IL15 receptor superagonist complex, designed to optimize in vivo persistence and trans-presentation, thereby activating and expanding natural killer (NK) cells and CD8⁺ T cells. Monoclonal antibodies (mAbs) direct Fc receptor-bearing immune cells, including NK cells, to recognize and eliminate cancer targets. The ability of IL15R agonists to enhance tumor-targeting mAbs in patients has not been reported previously.

PATIENTS AND METHODS

Relapsed/refractory patients with indolent non-Hodgkin lymphoma were treated with rituximab and intravenous or subcutaneous N-803 on an open-label, dose-escalation phase I study using a 3+3 design (NCT02384954). Primary endpoint was maximum tolerated dose. Immune correlates were performed using multidimensional analysis via mass cytometry and cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq) which simultaneously measures protein and single-cell RNA expression.

RESULTS

This immunotherapy combination was safe and well tolerated and resulted in durable clinical responses including in rituximab-refractory patients. Subcutaneous N-803 plus rituximab induced sustained proliferation, expansion, and activation of peripheral blood NK cells and CD8 T cells, with increased NK cell and T cells present 8 weeks following last N-803 treatment. CITE-seq revealed a therapy-altered NK cell molecular program, including enhancement of AP-1 transcription factor. Furthermore, the monocyte transcriptional program was remodeled with enhanced MHC expression and antigen-presentation genes.

CONCLUSIONS

N-803 combines with mAbs to enhance tumor targeting in patients, and warrants further investigation in combination with immunotherapies.

Impact of rituximab on the T-cell flow cytometric crossmatch

Rituximab is frequently used in the setting of ABO-incompatible renal transplants, and highly sensitized patients. Its interference with B-cell flow cytometric crossmatch (B-FCXM) is well known. However, its effect on the T-cell flow cytometric crossmatch (T-FCXM) has not been described. We aimed to evaluate the effect of rituximab on the T-FCXM using non-pronase and pronase treated donor lymphocytes and compare results with the single antigen bead (SAB) assay. In this retrospective study, 28 patients on rituximab therapy were evaluated against 30 donors. Using non-pronase treated donor lymphocytes, all 30 FCXMs showed strong B-cell positivity {median (IQR) B-cell ratio: 184.65 (253.17)} which significantly reduced {1.0 (1.18); p < 0.00001} with pronase treatment. 'T-cell tailing' phenomenon was observed in 17/30 FCXMs in the non-pronase group as a 'tail of T-cells', indicating a rare sub-population. However, it disappeared in the pronase-treated group. SAB assay did not show donor-specific antibodies (DSA) in all 17 patients with 'T-cell tailing' phenomenon. Although, rituximab is described to impact only B-FCXM, we have consistently found 'T-cell tailing' in 57% of T-FCXMs, which clears with pronase treatment. The 'T-cell tailing' led to weak positive T-FCMX ratios due to increased MFI in the FL1 channel. However, the absence of DSA in all recipients reinforces the fact that this is a false positive finding and should not be misconstrued as a possible class I DSA. Structural homology of Fc receptors on activated T-cells to CD20 could be a possible explanation of the same and provide insight into a novel mechanism of action of rituximab.

Metabolism and Distribution of Novel Tumor Targeting Drugs In Vivo

BACKGROUND

As a new tumor therapy, targeted therapy is becoming a hot topic due to its high efficiency and low toxicity. Drug effects of targeted tumor drugs are closely related to pharmacokinetics, so it is important to understand their distribution and metabolism in vivo.

METHODS

A systematic review of the literature on the metabolism and distribution of targeted drugs over the past 20 years was conducted, and the pharmacokinetic parameters of approved targeted drugs were summarized in combination with the FDA's drug instructions. Targeting drugs are divided into two categories: small molecule inhibitors and monoclonal antibodies. Novel targeting drugs and their mechanisms of action, which have been developed in recent years, are summarized. The distribution and metabolic processes of each drug in the human body are reviewed.

RESULTS

In this review, we found that the distribution and metabolism of small molecule kinase inhibitors (TKI) and monoclonal antibodies (mAb) showed different characteristics based on the differences of action mechanism and molecular characteristics. TKI absorbed rapidly (Tmax ≈ 1-4 h) and distributed in large amounts (Vd > 100 L). It was mainly oxidized and reduced by cytochrome P450 CYP3A4. However, due to the large molecular diameter, mAb was distributed to tissues slowly, and the volume of distribution was usually very low (Vd < 10 L). It was mainly hydrolyzed and metabolized into peptides and amino acids by protease hydrolysis. In addition, some of the latest drugs are still in clinical trials, and the in vivo process still needs further study.

CONCLUSION

According to the summary of the research progress of the existing targeting drugs, it is found that they have high specificity, but there are still deficiencies in drug resistance and safety. Therefore, the development of safer and more effective targeted drugs is the future research direction. Meanwhile, this study also provides a theoretical basis for clinical accurate drug delivery.

Efficacy and safety of CD19 chimeric antigen receptor T cells in the treatment of 11 patients with relapsed/refractory B-cell lymphoma: a single-center study

Background

No effective treatment exist for patients with relapsed and refractory B-cell lymphoma, until the advent of anti-CD19 chimeric antigen receptor (CAR) T-cells. Therefore, this study aimed to explore the factors affecting the efficacy of anti-CD19 CAR T-cell and the adverse reactions of the therapy.

Methods

We recruited 11 patients with relapsed and refractory B-cell lymphoma. The number of anti-CD19 CAR T-cells, proliferation, and adverse reactions were recorded in detail, to explore the relationship between the factors affecting the efficacy of anti-CD19 CAR T-cell and the long-term survival of patients.

Results

The 11 patients in our study had a total overall response rate of 100%, after receiving anti-CD19 CAR T-cells. The median follow-up was 253 days (range, 130-1,017 days). The median overall survival (OS) and median progression-free survival (PFS) were not reached. After 3 months of treatment, the complete remission (CR) rate was 63.6% (7/11). As of December 7, 2019, 5 patients had maintained CR for a period exceeding 1 year, including 2 patients who had maintained CR for more than 1,000 days. The patients who received 3 or 4 lines of chemotherapy were more likely to have sustained remission than the patients who received <2 or >4 lines of chemotherapy. Each of the 4 patients in the study who had diffuse large B cell lymphoma (DLBCL) progression all had high myc protein expression (positive incidence: 30-80%). The incidence of Grade 2 cytokine release syndrome (CRS) was 36.4% (4/11), and Grade 3 CAR T-cell-related encephalopathy syndrome (CRES) was experienced by 1 patient. The occurrence of adverse reactions was not significantly related to the infusion dose, peak amplification time, or maximum copy amount. The immunoglobulin levels of the four patients who died showed a significant downward trend. Interleukin-1β (IL-1β), interferon-γ (IFN-γ), interleukin-10 (IL-10), and interleukin-17A (IL-17A) appeared to be associated with the occurrence of CRS and CRES.

Conclusions

Anti-CD19 CAR T-cell treatment is a new therapy for patients with relapsed and refractory B-cell lymphoma. Among the small sample size in this study, it demonstrated high efficiency and safety.

Comparison of gene regulatory networks to identify pathogenic genes for lymphoma

Lymphoma is the most complicated cancer that can be divided into several tens of subtypes. It may occur in any part of body that has lymphocytes, and is closely correlated with diverse environmental factors such as the ionizing radiation, chemocarcinogenesis, and virus infection. All the environmental factors affect the lymphoma through genes. Identifying pathogenic genes for lymphoma is consequently an essential task to understand its complexity in a unified framework. In this paper, we propose a new method to expose high-confident edges in gene regulatory networks (GRNs) for a total of 32 organs, called Filtered GRNs (f-GRNs), comparison of which gives us a proper reference for the Lymphoma, i.e. the B-lymphocytes cells, whose f-GRN is closest with that for the Lymphoma. By using the Gene Ontology and Biological Process analysis we display the differences of the two networks' hubs in biological functions. Matching with the Genecards shows that most of the hubs take part in the genetic information transmission and expression, except a specific gene of Retinoic Acid Receptor Alpha (RARA) that encodes the retinoic acid receptor. In the lymphoma, the genes in the RARA ego-network are involved in two cancer pathways, and the RARA is present only in these cancer pathways. For the lymphoid B cells, however, the genes in the RARA ego-network do not participate in cancer-related pathways.

Selective targeting of cancer signaling pathways with nanomedicines: challenges and progress

Cancer is one of the leading causes of death worldwide. Regardless of advances in understanding the molecular mechanics of cancer, its treatment is still lacking and the death rates for many forms of the disease remain the same as six decades ago. Although a variety of therapeutic agents and strategies have been reported, these therapies often failed to provide efficient therapy to patients as a consequence of the inability to deliver right and adequate chemotherapeutic agents to the right place. However, the situation has started to revolutionize substantially with the advent of novel 'targeted' nanocarrier-based cancer therapies. Such therapies hold great potential in cancer management as they are biocompatible, tailored to specific needs, tolerated and deliver enough drugs at the targeted site. Their use also enhances the delivery of chemotherapeutics by improving biodistribution, lowering toxicity, inhibiting degradation and increasing cellular uptake. However, in some instances, nonselective targeting is not enough and the inclusion of a ligand moiety is required to achieve tumor targeting and enhanced drug accumulation at the tumor site. This contemporary review outlines the targeting potential of nanocarriers, highlighting the essentiality of nanoparticles, tumor-associated molecular signaling pathways, and various biological and pathophysiological barriers.

A Review on Nano-Based Drug Delivery System for Cancer Chemoimmunotherapy

Although notable progress has been made on novel cancer treatments, the overall survival rate and therapeutic effects are still unsatisfactory for cancer patients. Chemoimmunotherapy, combining chemotherapeutics and immunotherapeutic drugs, has emerged as a promising approach for cancer treatment, with the advantages of cooperating two kinds of treatment mechanism, reducing the dosage of the drug and enhancing therapeutic effect. Moreover, nano-based drug delivery system (NDDS) was applied to encapsulate chemotherapeutic agents and exhibited outstanding properties such as targeted delivery, tumor microenvironment response and site-specific release. Several nanocarriers have been approved in clinical cancer chemotherapy and showed significant improvement in therapeutic efficiency compared with traditional formulations, such as liposomes (Doxil®, Lipusu®), nanoparticles (Abraxane®) and micelles (Genexol-PM®). The applications of NDDS to chemoimmunotherapy would be a powerful strategy for future cancer treatment, which could greatly enhance the therapeutic efficacy, reduce the side effects and optimize the clinical outcomes of cancer patients. Herein, the current approaches of cancer immunotherapy and chemoimmunotherapy were discussed, and recent advances of NDDS applied for chemoimmunotherapy were further reviewed.

Therapeutic Monoclonal Antibodies in Clinical Practice against Cancer

The importance of monoclonal antibodies in oncology has increased drastically following the discovery of Milstein and Kohler. Since the first approval of the monoclonal antibody, i.e. Rituximab in 1997 by the FDA, there was a decline in further applications but this number has significantly increased over the last three decades for various therapeutic applications due to the lesser side effects in comparison to the traditional chemotherapy methods. Presently, numerous monoclonal antibodies have been approved and many are in queue for approval as a strong therapeutic agent for treating hematologic malignancies and solid tumors. The main target checkpoints for the monoclonal antibodies against cancer cells include EGFR, VEGF, CD and tyrosine kinase which are overexpressed in malignant cells. Other immune checkpoints like CTLA-4, PD-1 and PD-1 receptors targeted by the recently developed antibodies increase the capability of the immune system in destroying the cancerous cells. Here, in this review, the mechanism of action, uses and target points of the approved mAbs against cancer have been summarized.

Clinical Response and Pattern of B cell Suppression with Single Low Dose Rituximab in Nephrology

Background

There is no consensus regarding dose and frequency of rituximab in nephrology with extrapolation of doses used in treating lymphoproliferative disorders. There are no guidelines on targeting initial and subsequent doses on the basis of CD19⁺ B cells.

Methods

Initially, 100 mg rituximab was given to 42 adults with steroid-dependent nephrotic syndrome (SDNS) and frequently relapsing nephrotic syndrome (FRNS), idiopathic membranous nephropathy (MN), and high-immunologic-risk kidney transplantation. Absolute and percentage levels of CD19 B cells and clinical status were assessed at baseline, days 30, 90, and 180, and at 1 year. Subsequent doses of rituximab were on the basis of CD19 B cell reconstitution and clinical response.

Results

CD19 B cell percentage decreased from 16.3 ± 7.6 to 0.3 ± 0.3 (P≤0.001), 1.9 ± 1.7 (P≤0.001), and 4.0 ± 4.5 (P=0.005) by 30, 90, and 180 days, respectively. Suppression of CD19 B cell count below 1% at days 30, 90, and 180 was seen in 40 of 42 (95.2%), 18 of 42 (42.9%), and 7 of 42 (16.7%) patients, respectively. Of 30 with SDNS and FRNS followed up for 1 year, 29 (96.7%) went into remission at day 30. Remission was sustained in 23 (76.6%) at day 180 and 21 (70%) at 1 year. There was a significant decrease (P<0.001) in the dose of steroids needed to maintain remission at 180 days after rituximab (0.27 ± 0.02 mg/kg to 0.02 ± 0.00 mg/kg). CD19 B cell percentage at 90 days correlated with relapse (P=0.001; odds ratio 1.42; 95% confidence interval, 1.25 to 2.57). Eighteen (60%) required an additional dose. Of five with MN, four achieved remission by 6 months, which was sustained in three by 1 year. Of the seven kidney transplant recipients, two had antibody-mediated rejections, although CD19 B cells were suppressed even at 1 year.

Conclusions

Low-dose rituximab induces sustained depletion of CD19 B cells for up to 90 days. Its role in preventing relapses in SDNS, FRNS, MN, and rejection needs further study.

Atomic Force Microscopy in Mechanoimmunology Analysis: A New Perspective for Cancer Immunotherapy

Immunotherapy has remarkable success outcomes against hematological malignancies with high rates of complete remission. To date, many studies have been conducted to increase its effectiveness in other types of cancer. However, it still yields unsatisfying results in solid tumor therapy. This limitation is partly attributed to the lack of understanding of how immunotherapy works in cancer from other perspectives. The traditional studies focus on the biological and chemical perspectives to determine which molecular substrates are involved in the immune system that can eradicate cancer cells. In the last decades, accumulating evidence has shown that physical properties also play important roles in the immune system to combat cancer, which is studied in mechanoimmunology. Mechanoimmunology analysis requires special tools; and herein, atomic force microscopy (AFM) appears as a versatile tool to determine and quantify the mechanical properties of a sample in nanometer precisions. Owing to its multifunctional capabilities, AFM can be used to explore immune system function from the physical perspective. This review paper explains the mechanoimmunology of how immune systems work through AFM, which includes mechanosignaling, mechanosensing, and mechanotransduction, with the aim to deepen the understanding of the mechanistic role of immunotherapy for further development in cancer treatment.

Reprogramming the Constant Region of Immunoglobulin G Subclasses for Enhanced Therapeutic Potency against Cancer

The constant region of immunoglobulin (Ig) G antibodies is responsible for their effector immune mechanism and prolongs serum half-life, while the fragment variable (Fv) region is responsible for cellular or tissue targeting. Therefore, antibody engineering for cancer therapeutics focuses on both functional efficacy of the constant region and tissue- or cell-specificity of the Fv region. In the functional aspect of therapeutic purposes, antibody engineers in both academia and industry have capitalized on the constant region of different IgG subclasses and engineered the constant region to enhance therapeutic efficacy against cancer, leading to a number of successes for cancer patients in clinical settings. In this article, we review IgG subclasses for cancer therapeutics, including (i) IgG1, (ii) IgG2, 3, and 4, (iii) recent findings on Fc receptor functions, and (iv) future directions of reprogramming the constant region of IgG to maximize the efficacy of antibody drug molecules in cancer patients.

Targeting Immunophenotypic Markers on Leukemic Stem Cells: How Lessons from Current Approaches and Advances in the Leukemia Stem Cell (LSC) Model Can Inform Better Strategies for Treating Acute Myeloid Leukemia (AML)

Therapies targeting cell-surface antigens in acute myeloid leukemia (AML) have been tested over the past 20 years with limited improvement in overall survival. Recent advances in the understanding of AML pathogenesis support therapeutic targeting of leukemia stem cells as the most promising avenue toward a cure. In this review, we provide an overview of the evolving leukemia stem cell (LSC) model, including evidence of the cell of origin, cellular and molecular disease architecture, and source of relapse in AML. In addition, we explore limitations of current targeted strategies utilized in AML and describe the various immunophenotypic antigens that have been proposed as LSC-directed therapeutic targets. We draw lessons from current approaches as well as from the (pre)-LSC model to suggest criteria that immunophenotypic targets should meet for more specific and effective elimination of disease-initiating clones, highlighting in detail a few targets that we suggest fit these criteria most completely.

Reinforcing the primary immunotherapy modulators against acute leukemia; monoclonal antibodies in AML

Recent therapeutic advances in cancer treatment recruit immune system potentiation against malignant cells. Numerous ongoing clinical trials on immunotherapy methods, either monotherapy or combination therapy, are investigating the impeding factors on the way of acute myeloid leukemia (AML) treatment. Due to the genetic diversity in AML progenitors, combining various strategies is more likely to be useful for improving patient outcomes. This review describes the details of applying monoclonal antibodies against AML, focusing on CD33, CD123, FLT3, CD45 and CD66 targeting. Furthermore, it clarifies the importance of immunotoxins, bispecific antibodies, chimeric antigen receptor (CAR)-T cells and T cell receptor-modified cells as reinforcing agents for monoclonal antibodies.

Radioimmunotherapy in Non-Hodgkin's Lymphoma: Retrospective Adverse Event Profiling of Zevalin and Bexxar

The development of monoclonal antibodies has dramatically changed the outcome of patients with non-Hodgkin’s lymphoma (NHL), the most common hematological malignancy. However, despite the satisfying results of monoclonal antibody treatment, only few NHL patients are permanently cured with single-agent therapies. In this context, radioimmunotherapy, the administration of radionuclides conjugated to monoclonal antibodies, is aimed to augment the single-agent efficacy of immunotherapy in order to deliver targeted radiation to tumors, particularly CD20+ B-cell lymphomas. Based on evidence from several trials in NHL, the radiolabeled antibodies ⁹⁰Y-ibritumomab tiuxetan (Zevalin, Spectrum Pharmaceuticals) and ¹³¹I-tositumomab (Bexxar, GlaxoSmithKline) received FDA approval in 2002 and 2003, respectively. However, none of the two radioimmunotherapeutic agents has been broadly applied in clinical practice. The main reason for the under-utilization of radioimmunotherapy includes economic and logistic considerations. However, concerns about potential side effects have also been raised. Driven by these developments, we performed retrospective analysis of adverse events reporting Zevalin or Bexxar, extracted from the FDA’s Adverse Event Reporting System (FAERS) and the World Health Organization’s VigiBase repository. Our results indicate that the two radioimmunotherapeutic agents have both related and distinct side effect profiles and confirm their known toxicological considerations. Our work also suggests that computational analysis of real-world post-marketing data can provide informative clinical insights. While more prospective studies are necessary to fully characterize the efficacy and safety of radioimmunotherapy, we expect that it has not yet reached its full therapeutic potential in modern hematological oncology.

[Efficacy and safety of CD19 chimeric antigen receptor T cells for the treatment of 22 patients with B-cell lymphoma]

目的

探讨CD19 CAR-T治疗B细胞淋巴瘤的疗效及安全性。

方法

评估2017年2月1日至2018年7月1日CD19 CAR-T治疗22例B细胞淋巴瘤患者的疗效及不良反应情况。

结果

22例患者输注CD19 CAR-T后，总体完全缓解（CR）率为45.5%，部分缓解（PR）率为31.8%，总有效率为77.3%。其中12例复发难治患者9例有效，2例达CR，7例PR；10例微小残留病（MRD）阳性患者，8例MRD转阴。全部患者外周血中均检测到CD19 CAR-T细胞在体内增殖，复发难治患者与MRD阳性患者T细胞增殖的达峰时间分别为治疗后第4.5（1~12）天和治疗后第12（5~19）天，外周血CAR-T细胞分别占总的T淋巴细胞的4.02%（2.23%~28.60%）和10.10%（3.55%~24.74%）。MRD转阴患者持续缓解，中位随访8（3~18）个月均未复发，且此组患者有3例联合PD-1抗体治疗，均达CR。复发难治患者中，7例CAR-T治疗后达PR患者疗效保持时间为1.5~6.0个月，PD-1表达率为25.7%~55.3%，5例CAR-T治疗无效患者PD-1均高表达；共有3例患者联合应用PD-1抗体，其中2例有效；2例CAR-T治疗后达CR患者中1例行异基因造血干细胞移植，另1例随访12个月仍持续缓解。22例患者输注CAR-T细胞后14例发生不同程度的细胞因子释放综合征（CRS），其中9例为1级CRS，4例为2级CRS，其中1例复发难治患者发生3级CRS，经糖皮质激素、IL-6抗体治疗后CRS得到控制。治疗有效的17例患者中14例发生CRS，治疗无效的5例患者均未发生CRS。难治复发患者发生CRS的严重程度高于MRD阳性患者。

结论

CD19 CAR-T在CD19⁺ B细胞淋巴瘤中取得了疗效。CAR-T联合免疫检查点抑制剂的应用能够更好地提高疗效，CAR-T细胞治疗可作为复发难治患者的挽救治疗，清除B细胞淋巴瘤的MRD效果更好且不良反应小。

Update on the role of venetoclax and rituximab in the treatment of relapsed or refractory CLL

For the treatment of mature B cell malignancies including chronic lymphocytic leukemia (CLL), the last 5 years has brought major advances in the application of targeted therapies. Whilst monoclonal anti-CD20 agents such as rituximab have a central role in combination with traditional cytotoxic therapy, their combination with novel agents that target the B cell receptor signaling pathway and other intracellular mechanisms of B cell proliferation is a new approach to treatment. Venetoclax is a highly specific novel agent inhibiting the bcl-2 anti-apoptotic pathway and has potent activity in CLL. Its combination with rituximab results in deeper and more durable responses and this regimen is a valuable option in the treatment of relapsed or refractory CLL including adverse prognostic variants such as cases that are fludarabine refractory or harbor the 17p chromosomal deletion. This review centers on the use of venetoclax and rituximab in relapsed or refractory CLL.

Rituximab and reduced-intensity chemotherapy in children and adolescents with mature B-cell lymphoma: interim results for 231 patients enrolled in the second Russian-Belorussian multicentre study B-NHL-2010M

The value of adding rituximab to chemotherapy in children with aggressive B-cell non-Hodgkin lymphoma (B-NHL) is still insufficiently studied. We enrolled 231 patients [mean age 9 years old (range 2-17); male:female ratio 3·4:1] with Burkitt (BL, 179 patients, 76·7%), diffuse large B-cell (32 patients, 14%), primary mediastinal B-cell (14 patients, 6%), and other (6 patients, 2·6%) B-cell lymphomas in a prospective study of immuno-chemotherapy. Stages were I-II in 32% and III-IV in 68% of the patients. Four doses of 375 mg/m² rituximab were added to the Berlin-Frankfurt-Munster-NHL-90-like chemotherapy, with methotrexate being reduced or omitted in the first 2 induction blocks. The complete remission rate was 100% in limited-stage and 91·4% in advanced-stage patients. Five advanced-stage patients (2·2%) died in induction and 1 patient with stage 2 B-NHL died in remission; 11 patients in the high-risk group progressed on therapy (3 non-BL are alive after salvage) and 5 relapsed. Sixteen patients (9·7%) with advanced stage disease proceeded to transplant. With a median follow-up of 46 months, 98·5 ± 1% of patients with limited disease and 88·1 ± 2% (88·1% in Risk Group 3; 82·6% in Risk Group 4) in advanced stages are alive. This study confirmed that combined immunochemotherapy for B-lymphomas is highly effective in children, despite reducing the intensity of the induction blocks.

Pharmacokinetic and Pharmacodynamic Relationship of Blinatumomab in Patients with Non-Hodgkin Lymphoma

BACKGROUND

Blinatumomab is a bispecific T-cell engager (BiTE®) antibody construct targeting CD3ε on T cells and CD19 on B cells. We describe the relationship between pharmacokinetics (PK) of blinatumomab and pharmacodynamic (PD) changes in peripheral lymphocytes, serum cytokines, and tumor size in patients with non-Hodgkin lymphoma (NHL).

METHODS

In a phase 1 study, 76 patients with relapsed/refractory NHL received blinatumomab by continuous intravenous infusion at various doses (0.5 to 90 µg/m2/day). PD changes were analyzed with respect to dose, blinatumomab concentration at steady state (Css), and cumulative area under the concentration-versus-time curve (AUCcum).

RESULTS

B-cell depletion occurred within 48 hours at doses ≥5 µg/m2/day, followed first-order kinetics, and was blinatumomab exposure-dependent. Change in tumor size depended on systemic blinatumomab exposure and treatment duration and could be fitted to an Emax model, which predicted a 50% reduction in tumor size at AUCcum of ≥1,340 h×µg/L and Css of ≥1,830 pg/mL, corresponding to a blinatumomab dose of 47 µg/m2/day for 28 days. The magnitude of transient cytokine elevation, observed within 1-2 days of infusion start, was dose-dependent, with less pronounced elevation at low starting doses.

CONCLUSION

B-lymphocyte depletion following blinatumomab infusion was exposure-dependent. Transient cytokine elevation increased with dose; it was less pronounced at low starting doses. Tumor response was a function of exposure, suggesting utility for the PK/PD relationship in dose selection for future studies, including NHL and other malignant settings.

Targeting CD47 as a cancer therapeutic strategy: the cutaneous T-cell lymphoma experience

PURPOSE OF REVIEW

To describe the relevance of CD47 in the tumor microenvironment and summarize data on anti-CD47 therapies, including its role in cutaneous T-cell lymphoma (CTCL).

RECENT FINDINGS

CD47 is expressed on all normal cells and targets SIRPα on the surface of myeloid cells. However, CD47 is found to be overexpressed on cancer cells. CD47-SIRPα interaction inhibits macrophage phagocytosis, allowing cancer cells to escape immune surveillance. Current focus in immunotherapy has been targeted toward inhibiting CD47-SIRPα interaction via anti-CD47 antibodies. This activates innate immunity, promoting cancer cell destruction by macrophages. It also activates adaptive immunity resulting in antigen-presentation, mostly by dendritic cells, leading to antitumor cytotoxic reactions. Current CD47 antagonists undergoing clinical trials include Hu5F9 (an anti-CD47 antibody that directly inhibits the CD47-SIRPα interaction) and TTI-621, (a fusion protein composed of CD47 binding domain of human SIRPα and linked to the Fc region of IgG1). These agents have continued to show strong efficacy against solid and hematological tumors.

SUMMARY

In the CTCL tumor microenvironment, increased immune checkpoint inhibition expression via CD47 bound to SIRPα correlates with a more advanced disease state. Continued success in treating these patients requires further studies on CD47 antagonists, specifically when combined with other antibodies.

Targeting the Antibody Checkpoints to Enhance Cancer Immunotherapy-Focus on FcγRIIB

Immunotherapy with therapeutic antibodies has increased survival for patients with hematologic and solid cancers. Still, a significant fraction of patients fails to respond to therapy or acquire resistance. Understanding and overcoming mechanisms of resistance to antibody drugs, and in particular those common to antibody drugs as a class, is therefore highly warranted and holds promise to improve response rates, duration of response and potentially overall survival. Activating and inhibitory Fc gamma receptors (FcγR) are known to coordinately regulate therapeutic activity of tumor direct-targeting antibodies. Similar, but also divergent, roles for FcγRs in controlling efficacy of immune modulatory antibodies e.g., checkpoint inhibitors have been indicated from mouse studies, and were recently implicated in contributing to efficacy in the human clinical setting. Here we discuss evidence and mechanisms by which Fc gamma receptors–the “antibody checkpoints”–regulate antibody-induced antitumor immunity. We further discuss how targeted blockade of the sole known inhibitory antibody checkpoint FcγRIIB may help overcome resistance and boost activity of clinically validated and emerging antibodies in cancer immunotherapy.

Rituximab and Fibrillary Glomerulonephritis: Interest of B Cell Reconstitution Monitoring

Fibrillary glomerulonephritis (FGN) is a rare glomerular disease characterized by glomerular deposition of randomly arranged non-amyloid fibrils. FGN has a poor renal prognosis and its optimal treatment is a medical challenge. Rituximab therapy has recently emerged as a promising approach even though its mechanism of action remains hypothetical. We describe the case of a 55-year-old woman with FGN successfully treated by rituximab. During the 36-month follow-up, she had three relapses of FGN, occurring each time in the context of B cell recovery. Investigation of the distribution of B cell subpopulations at the time of the third relapse showed, as previously described for some immunological diseases, an increase in the proportion of switched memory B cells relative to healthy subjects, whereas global memory B cell pool was not yet recovered. This case suggests that B cell reconstitution should be carefully monitored in the management of FGN treated with rituximab.

Blocking "don't eat me" signal of CD47-SIRPα in hematological malignancies, an in-depth review

Hematological malignancies express high levels of CD47 as a mechanism of immune evasion. CD47-SIRPα triggers a cascade of events that inhibit phagocytosis. Preclinical research supports several models of antibody-mediated blockade of CD47-SIRPα resulting in cell death signaling, phagocytosis of cells bearing stress signals, and priming of tumor-specific T cell responses. Four different antibody molecules designed to target the CD47-SIRPα interaction in malignancy are currently being studied in clinical trials: Hu5F9-G4, CC-90002, TTI-621, and ALX-148. Hu5F9-G4, a humanized anti-CD47 blocking antibody is currently being studied in four different Phase I trials. These studies may lay the groundwork for therapeutic bispecific antibodies. Bispecific antibody (CD20-CD47SL) fusion of anti-CD20 (Rituximab) and anti-CD47 also demonstrated a synergistic effect against lymphoma in preclinical models. This review summarizes the large body of preclinical evidence and emerging clinical data supporting the use of antibodies designed to target the CD47-SIRPα interaction in leukemia, lymphoma and multiple myeloma.

Targeting the CD47-SIRPα signaling axis: current studies on B-cell lymphoma immunotherapy

The function of the immune system in cancer initiation and progression has been widely examined. Notably, immunotherapy has become a promising approach for cancer treatment. CD47, a member of the immunoglobulin superfamily, plays an important role in the immune regulation of cancer by binding to SIRPα. Multiple studies have detected high CD47 expression on the surface of tumor cells, which indicates poor prognosis. Treatments that block the interaction of CD47 and SIRPα significantly suppress tumor growth and metastasis through diverse mechanisms, such as phagocytosis, antibody-dependent cellular cytotoxicity, and apoptosis. Recently, several studies have reported increased CD47 expression on different types of lymphoma cells, indicating that the CD47-SIRPα pathway can be used as a therapeutic target in lymphoma. This review focuses on the role of CD47-SIRPα in B-cell lymphoma and discusses promising therapeutic strategies targeting the CD47-SIRPα axis, which yield insights into the immunotherapy of B-cell lymphoma.

Interleukin-15 suppresses gastric cancer liver metastases by enhancing natural killer cell activity in a murine model

Interleukin (IL)-15 is a promising cytokine for cancer immunotherapy as it is a critical factor for the proliferation and activation of natural killer (NK) cells. Previous studies have suggested critical roles of IL-15 in tumor invasion and metastasis. However, the association between IL-15 and liver metastasis of gastric cancer (LMGC) remains unknown. The present study investigated the therapeutic efficacy of recombinant mouse IL-15 (rmIL-15) in murine LMGC models, in which stable green fluorescent protein (GFP)-expressing MKN45 cells (MKN45-GFP cells) were injected into the spleen parenchyma of mice for liver metastasis. At different treatments (high dose group: 2.5 µg of rmIL-15; low dose group: 0.2 µg of rmIL-15; control group: PBS), it was found that rmIL-15 decreased the formation of liver metastasis sites. Additionally, this treatment lead to improved survival of mice following tumor cell transplantation. Treatment with a high dose of rmIL-15 provided greater therapeutic efficacy by prolonged survival of the mice compared with low dose group and control group. It was found that NK cells isolated from the liver that received the high dose of rmIL-15 showed stronger cytotoxic activity compared with the other two groups on the target cells. These findings hold significant importance for the use of IL-15 as a potential adjuvant/therapeutic for liver metastasis from gastric cancer.