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Summary Since the approval of the CD20‐targeting monoclonal antibody (mAb) rituximab for the treatment of lymphoma in 1997, mAb therapy has significantly transformed cancer treatment. With over 90 FDA‐approved mAbs for the treatment of various hematological and solid cancers, modern cancer treatment relies heavily on these therapies. The overwhelming success of mAbs as cancer therapeutics is attributed to their broad applicability, high safety profile, and precise targeting of cancer‐associated surface antigens. Furthermore, mAbs can induce various anti‐tumor cytotoxic effector mechanisms including antibody‐dependent cellular cytotoxicity (ADCC), antibody‐dependent cellular phagocytosis (ADCP), and complement‐dependent cytotoxicity (CDC), all of which are mediated via their fragment crystallizable (Fc) domain. Over the past decades, these effector mechanisms have been substantially improved through Fc domain engineering. In this review, we will outline the different approaches to enhance Fc effector functions via Fc engineering of mAbs, with a specific emphasis on the so‐called “HexaBody” technology, which is designed to enhance the hexamerization of mAbs on the target cell surface, thereby inducing greater complement activation, CDC, and receptor clustering. The review will summarize the development, preclinical, and clinical testing of several HexaBodies designed for the treatment of B‐cell malignancies, as well as the potential use of the HexaBody technology beyond Fc‐mediated effector functions. [ABSTRACT FROM AUTHOR]

Summary: The bendamustine–rituximab (BR) schedule is an efficient first‐line therapy in Waldenström macroglobulinaemia (WM). A previous analysis of 69 patients who received this treatment confirmed a high response rate and good progression‐free (PFS) and overall survival (OS). With a median follow‐up of 76.1 months (95% confidence interval [CI] 69.9–80.6), 5‐year outcome is still excellent at 66.63% (95% CI 56.09–79.17) for PFS and 80.01% (95% CI 70.82–90.41) for OS. The rate of secondary cancers is 17.66% (IQR 7.99–27.64) at 66 months. Relapsed patients who received ibrutinib as second‐line clearly benefited from this schedule. This confirms current recommendations suggesting BR long‐term efficacy as first‐line option in WM. [ABSTRACT FROM AUTHOR]

Summary: Due in part to racial disparities and underrepresentation in clinical studies, optimal therapies for Black patients with multiple myeloma remain undefined. This final analysis of GRIFFIN by race showed that the addition of daratumumab (D) to lenalidomide/bortezomib/dexamethasone (RVd) provides clinical benefit among both Black and White transplant‐eligible newly diagnosed patients compared with RVd alone. However, Black patients were more likely to discontinue ≥1 drug due to treatment‐emergent adverse events. In summary, these findings suggest a benefit of D‐RVd front‐line therapy among Black and White patients and underscore the importance of equitable treatment access for all patients. [ABSTRACT FROM AUTHOR]

Summary: Systemic light chain (AL) amyloidosis is a relapsing plasma cell disorder. Therapy is limited, particularly for triple‐class refractory disease. We report the use of belantamab mafodotin, a BCMA‐directed drug–antibody conjugate, for relapsed AL amyloidosis, including patients traditionally excluded from clinical trials. Thirty‐one patients were reviewed, with a median of three prior lines of therapy. The median follow‐up was 12 months (95% CI 4–19), and a median of five doses were delivered. The best haematological overall response rate was 71%, and the complete/very good partial response was 58%. Sixty‐eight percent had keratopathy and improved in all. Belantamab mafodotin has high efficacy and good tolerability in patients with relapsed AL amyloidosis. [ABSTRACT FROM AUTHOR]

Lipolysis‐stimulated lipoprotein receptor (LSR) is known as a lipoprotein receptor. LSR is expressed in various solid tumors, including epithelial ovarian, gastric, and colon cancers. High LSR expression is significantly associated with poor prognosis, but its role in cancer has not been fully elucidated. LSR belongs to the Ig protein superfamily, which is conserved in B7 family. Here, we assessed LSR as a novel immune checkpoint molecule. We developed a novel anti‐LSR antibody (#27‐6 mF‐18) that defects antibody‐dependent cellular cytotoxicity and complement‐dependent cytotoxicity activity. The #27‐6 mF‐18 cross‐reacts with both human and mouse LSR. We found that LSR was expressed on 4T1 murine breast cancer cell line. The #27‐6 mF‐18 exhibited antitumor effects against the 4T1 syngeneic tumor model, a poor immunogenic model refractory to treatment with anti‐PD‐1 or anti‐CTLA‐4 antibodies. Compared with control antibody‐treated mice, mice treated with #27‐6 mF‐18 showed significantly increased numbers of CD8+ T cells and a ratio of activated CD8+ T cells infiltrated in the tumor tissue. This antitumor effect was abrogated by CD8+ T‐cell depletion through anti‐CD8 antibody treatment, indicating that LSR negatively regulates tumor immunity by repressing CD8+ T cells. These findings show that LSR negatively regulates T‐cell immune activity. LSR targeting could provide immune checkpoint inhibitors for cancer immunotherapy. [ABSTRACT FROM AUTHOR]

Ischaemic neurovascular stroke represents a leading cause of death in the developed world. Preclinical and human epidemiological evidence implicates the corticotropin‐releasing factor (CRF) family of neuropeptides as mediators of acute neurovascular injury pathology. Preclinical investigations of the role of CRF, CRF receptors and CRF‐dependent activation of the hypothalamic–pituitary–adrenal (HPA) axis have pointed toward a tissue‐specific and temporal relationship between activation of these pathways and physiological outcomes. Based on the literature, the major phases of ischaemic stroke aetiology may be separated into an acute phase in which CRF and anti‐inflammatory stress signalling are beneficial and a chronic phase in which these contribute to neural degeneration, toxicity and apoptotic signalling. Significant gaps in knowledge remain regarding the pathway, temporality and systemic impact of CRF signalling and stress biology in neurovascular injury progression. Heterogeneity among experimental designs poses a challenge to defining the apparent reciprocal relationship between neurological injury and stress metabolism. Despite these challenges, it is our opinion that the elucidated temporality may be best matched with an antibody against CRF with a half‐life of days to weeks as opposed to minutes to hours as with small‐molecule CRF receptor antagonists. This state‐of‐the‐art review will take a multipronged approach to explore the expected potential benefit of a CRF antibody by modulating CRF and corticotropin‐releasing factor receptor 1 signalling, glucocorticoids and autonomic nervous system activity. Additionally, this review compares the modulation of CRF and HPA axis activity in neuropsychiatric diseases and their counterpart outcomes post‐stroke and assess lessons learned from antibody therapies in neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

Antibody‐based therapies could be led astray when target receptors are expressed on nontarget sites, and the on‐target toxicity poses critical challenges to clinical applications. Here, a biomimetic indirect active targeting (INTACT) strategy is proposed based on receptor expression disparities between nontarget sites and the targets. By prebinding the antibodies using cell membrane vesicles with appropriate receptor expressions, the INTACT strategy could filter out the interactions on nontarget sites due to their inferior receptor expression, whereas ensure on‐demand release at the targets by competitive binding. The strategy is verified on CD47 antibody, realizing drastic alleviation of its clinically concerned hematotoxicity on a series of animal models including humanized patient‐derived xenograft platforms, accompanied by preferable therapeutic effects. Furthermore, the INTACT strategy proves extensive applicability for various systems including antibody, antibody–drug conjugate, and targeted delivery systems, providing a potential platform refining the specificity for frontier antibody‐related therapies. [ABSTRACT FROM AUTHOR]

Summary: Treatment outcomes in multiple myeloma (MM) have improved dramatically over the past 10 years. However, patients with high‐risk disease such as those with Stage III disease by the Revised International Staging System, the presence of adverse cytogenetics, or who are refractory to proteosome inhibitors, immunomodulatory drugs and monoclonal antibodies may have dismal outcomes. These patients represent an urgent ongoing need in MM. One of the hallmarks of MM is immune dysfunction and a tumour‐permissive immune microenvironment. Ameliorating the immune‐paresis could lead to improved outcomes. The role of immunotherapies has been growing at an exponential pace with numerous agents under development in clinical trials. In the present review, we provide an overview of immunotherapies in MM, focussing on bispecific antibodies (BsAbs). We review efficacy outcomes from the published clinical trials and consider the important safety aspects of these therapies, in particular the risk of cytokine‐release syndrome and immune effector cell‐associated neurotoxicity syndrome, and how these compare with patients receiving chimeric antigen receptor T cells. We discuss the MM epitopes being targeted by BsAbs, either in clinical or preclinical stages, and we consider where these therapies might best fit within the future ever‐changing paradigm of MM treatment. [ABSTRACT FROM AUTHOR]

The Ig superfamily protein glycoprotein A33 (GPA33) has been implicated in immune dysregulation, but little is known about its expression in the immune compartment. Here, we comprehensively determined GPA33 expression patterns on human blood leukocyte subsets, using mass and flow cytometry. We found that GPA33 was expressed on fractions of B, dendritic, natural killer and innate lymphoid cells. Most prominent expression was found in the CD4+ T cell compartment. Naïve and CXCR5+ regulatory T cells were GPA33high, and naïve conventional CD4+ T cells expressed intermediate GPA33 levels. The expression pattern of GPA33 identified functional heterogeneity within the CD4+ central memory T cell (Tcm) population. GPA33+ CD4+ Tcm cells were fully undifferentiated, bona fide Tcm cells that lack immediate effector function, whereas GPA33– Tcm cells exhibited rapid effector functions and may represent an early stage of differentiation into effector/effector memory T cells before loss of CD62L. Expression of GPA33 in conventional CD4+ T cells suggests a role in localization and/or preservation of an undifferentiated state. These results form a basis to study the function of GPA33 and show it to be a useful marker to discriminate between different cellular subsets, especially in the CD4+ T cell lineage. [ABSTRACT FROM AUTHOR]

Systemic lupus erythematosus is an autoimmune syndrome characterized by the development of autoantibodies to a wide range of antigens. Together with B cells, respective self‐reactive T cells have an important contribution in disease progression as being responsible for inflammatory cytokines secretion, B cell activation and promoting amplification of the autoimmune response. Annexin A1 is expressed by many cell types and binds to phospholipids in a Ca2+‐dependent manner. Abnormal expression of annexin A1 was found on activated B and T cells in both murine and human autoimmunity suggesting its potential role as a therapeutic target. In the present study, we have investigated the possibility to suppress autoimmune manifestation in spontaneous mouse model of lupus using anti‐annexin A1 antibody. Groups of lupus‐prone MRL/lpr mice were treated with the anti‐annexin A1 monoclonal antibody, and the disease activity and survival of the animals were following up. Flow cytometry, ELISA assays, and histological and immunofluorescence kidney analyses were used to determine the levels of Annexin A1 expression, cytokines, anti‐dsDNA antibodies and kidney injuries. The administration of this monoclonal antibody to MRL/lpr mice resulted in suppression of IgG anti‐dsDNA antibody production, modulated IL‐10 secretion, decreased disease activity and prolonged survival compared with the control group. [ABSTRACT FROM AUTHOR]

Hepatocellular carcinoma (HCC) is a common and particularly fatal form of cancer for which very few drugs are effective. The fibroblast growth factor 19 (FGF19) has been viewed as a driver of HCC development and a potential Ab target for developing novel HCC therapy. However, a previously developed anti‐FGF19 Ab disrupted FGF19's normal regulatory function and caused severe bile‐acid‐related side‐effects despite of having potent antitumor effects in preclinical models. Here, we developed novel human Abs (G1A8 and HS29) that specifically target the N‐terminus of FGF19. Both Abs inhibited FGF19‐induced HCC cell proliferation in vitro and significantly suppressed HCC tumor growth in mouse models. Importantly, no bile‐acid‐related side effects were observed in preclinical cynomolgus monkeys. Fundamentally, our study demonstrates that it is possible to target FGF19 for anti‐HCC therapies without adversely affecting its normal bile acid regulatory function, and highlights the exciting promise of G1A8 or HS29 as potential therapy for HCC. [ABSTRACT FROM AUTHOR]

The C9orf72 repeat expansion causes amyotrophic lateral sclerosis and frontotemporal dementia, but the poor correlation between C9orf72‐specific pathology and TDP‐43 pathology linked to neurodegeneration hinders targeted therapeutic development. Here, we addressed the role of the aggregating dipeptide repeat proteins resulting from unconventional translation of the repeat in all reading frames. Poly‐GA promoted cytoplasmic mislocalization and aggregation of TDP‐43 non‐cell‐autonomously, and anti‐GA antibodies ameliorated TDP‐43 mislocalization in both donor and receiver cells. Cell‐to‐cell transmission of poly‐GA inhibited proteasome function in neighboring cells. Importantly, proteasome inhibition led to the accumulation of TDP‐43 ubiquitinated within the nuclear localization signal (NLS) at lysine 95. Mutagenesis of this ubiquitination site completely blocked poly‐GA‐dependent mislocalization of TDP‐43. Boosting proteasome function with rolipram reduced both poly‐GA and TDP‐43 aggregation. Our data from cell lines, primary neurons, transgenic mice, and patient tissue suggest that poly‐GA promotes TDP‐43 aggregation by inhibiting the proteasome cell‐autonomously and non‐cell‐autonomously, which can be prevented by inhibiting poly‐GA transmission with antibodies or boosting proteasome activity with rolipram. Synopsis: Poly‐GA promotes cytoplasmic mislocalization and aggregation of TDP‐43 via non‐cell‐autonomous proteasome inhibition and ubiquitination within the nuclear localization signal. Proteasome activation and poly‐GA antibodies ameliorate TDP‐43 pathology. Poly‐GA promotes TDP‐43 aggregation by proteasome inhibition even upon cell‐to‐cell transmission.Anti‐GA antibodies reduce TDP‐43 mislocalization.Ubiquitination within the NLS inhibits nuclear import of TDP‐43.Proteasome activation with rolipram ameliorates poly‐GA and TDP‐43 pathology. [ABSTRACT FROM AUTHOR]

Summary: The epidemiology, outcome and targeted immunotherapy in adolescent and young adult non‐Hodgkin and Hodgkin lymphoma were discussed during the 6th International Symposium on Childhood, Adolescent and Young Adult Non‐Hodgkin Lymphoma September 26th–29th 2018 in Rotterdam, the Netherlands. This review summarizes some of those presentations, as well as other current and novel antibody therapy, immune check‐point inhibitors, chimeric antigen receptor T cells, cancer vaccines and cytotoxic T lymphocyte therapy. [ABSTRACT FROM AUTHOR]

The present state of therapy for colorectal cancer (CRC) is far from satisfactory, highlighting the need for new targets for this disease. We identified a new CRC‐specific molecule, TMEM180, a predicted 11‐pass transmembrane protein that apparently functions as a cation symporter. We developed an anti‐TMEM180 mAb and then succeeded in humanizing the mAb. Immunohistochemistry (IHC) in CRC with the mAb showed a similar positivity rate as compared with anti‐epidermal growth factor receptor mAb, and IHC with anti‐TMEM180 mAb did not show staining in major organs used in this study. Immune electron microscopy clearly indicated that TMEM180 was present on the tumor exosome. The TMEM180 promoter region contains 10 hypoxia‐responsive element consensus sequences; accordingly, SW480 cells upregulated TMEM180 under low‐oxygen conditions. Anti‐TMEM180 mAb has in vitro antibody‐dependent cell‐mediated cytotoxicity and complement‐dependent cytotoxicity activity, and SW480 CRC xenografts were eradicated by the mAb. These data indicate that TMEM180 may be a new CRC marker and that a mAb against this protein could be used as antibody‐based therapy against CRC. We identified a new colorectal cancer (CRC)‐specific molecule, TMEM180, a predicted 11‐pass transmembrane protein that apparently functions as a cation symporter. Our anti‐TMEM180 mAb eradicated SW480 CRC xenografts. TMEM180 may be a new CRC marker and a mAb against this protein could be used as antibody‐based therapy against CRC. [ABSTRACT FROM AUTHOR]

Summary: This single‐centre retrospective observational study analysed the efficacy of retreatment with immunomodulatory agents (IMiDs) and proteasome inhibitors (PIs) after treatment with daratumumab monotherapy in patients with relapsed and/or refractory multiple myeloma (RRMM). In total 55 patients were treated with daratumumab monotherapy between 2010 and 2017. From this group 29 (53%) IMiD‐refractory patients were retreated with an IMiD after daratumumab and 6 (11%) PI‐refractory patients were retreated with a PI‐based regimen. For the IMiD‐refractory patients the overall response rate (ORR) was 52% (15/29 patients, partial response or better) upon IMiD retreatment, whereas the ORR to PI retreatment was 67% (4/6 patients) in the PI‐refractory group. The immunomodulatory effects of daratumumab may play a role in these high response rates in previously refractory patients. Due to the >6 month‐long persistence of daratumumab in the plasma the subsequent therapies can effectively be considered as combination therapy. Furthermore, the excellent tolerability of daratumumab treatment may enable patients to recover from prior lines of treatment and receive full dosing of subsequent therapies. In conclusion, a high proportion of RRMM patients benefitted from retreatment with IMiDs and PIs after daratumumab treatment. These retreatment options should therefore be explored in RRMM patients progressing on daratumumab monotherapy. [ABSTRACT FROM AUTHOR]

Remarkable effects of anti‐IL‐17A and anti‐IL‐23 antibodies on psoriasis indicate deep involvement of IL‐23/Th17 axis in the pathogenesis of psoriasis. According to the current immune theory, activation of dendritic cells initiates the generation of this axis. However, this theory is not enough to explain the mechanism, because the process of this activation is obscure and the antigen that is recognized by antigen‐presenting cells and pathogenic T cells has long been unidentified. Therefore, I thought of another theory as follows. Neutrophils are attracted by LTB4 at subcorneal portion and infiltrate into the epidermis. At the time of neutrophil migration through the basement membrane, basal keratinocytes in G0/G1 phase enter the cell cycle and begin to proliferate, according to the principle, "detachment‐mediated cell proliferation." This passing is continuously repeated and leads to elongation of rete ridges. The IL‐23/Th17 axis is generated by interactions between infiltrated neutrophils and keratinocytes. Briefly, neutrophils infiltrated into the epidermis secrete IL‐17A, which acts on keratinocytes to express CCL20, a ligand for the chemokine receptor CCR6. Keratinocytes perturbed by neutrophil infiltration produce HSP70, followed by production of IL‐23 via TLR4 using HSP70 as an endogenous ligand for TLR4. Natural Th17 cells expressing CCR6 are recruited to psoriatic epidermis and expand there in the presence of IL‐23 and IL‐1β. In this manner, the framework of the IL‐23/Th17 axis is created, which acts to maintain or exacerbate psoriasis. Noteworthy is the fact that this axis causes positive feedback loop, starting from IL‐17A production by neutrophils and ending in IL‐17A production by nTh17 cells. Therapeutic mechanisms of anti‐IL‐17A and anti‐IL‐23 antibodies, targeting neutrophils, were also described. [ABSTRACT FROM AUTHOR]

Summary: While rituximab has dramatically improved outcomes for patients with CD20+ malignancies for two decades, responses are not universal and resistance can develop. Obinutuzumab was developed to potentiate activity and overcome resistance. Pre‐clinical data suggests obinutuzumab is superior to rituximab at effecting B cell depletion; however recent phase III clinical trial results have been mixed. The decision of which antibody to employ will probably be further complicated by the approval of a subcutaneous preparation of rituximab and several anti‐CD20 biosimilars. Clinicians are now challenged with deciding whether to switch to obinutuzumab in approved settings, accepting the potential for increased toxicity and probable increased cost. The benefit conferred by obinutuzumab over rituximab may be context‐specific and vary based on histological subtype and immune integrity. This comprehensive review will explore the preclinical differences, investigate the proposed pathogenesis of rituximab resistance, compare the employed dosing strategies and interrogate available clinical results to help inform practice. [ABSTRACT FROM AUTHOR]

Inflammation is a critical phase in the healing of skin wounds. Excessive inflammation and inflammatory macrophages are known to cause impaired wound closure and outcome. This prompted us to test the role of IL-23 in IL-17 expression and in modulating wound inflammation and macrophage polarization. Full-thickness wounds (4 × 6 mm) were created on the dorsal surface of multiple genetically modified mouse models. Obese diabetic mouse wounds were treated with anti-IL-17A, anti-IL-23, or isotype-matched antibodies. We found IL-23- but not IL-12-deficient mice displayed significantly reduced IL-17 expression in wounds. This was rescued by delivery of recombinant IL-23. IL-23- and IL-17-deficient mice showed a significant increase in noninflammatory macrophages. Obese diabetic mice treated with anti-IL-17A and anti-IL-23p19 blocking antibodies had significantly improved wound reepithelialization. Similarly, IL-17-/- obese mice had accelerated wound closure, resulting in reduced iNOS expression and inflammatory macrophages while maintaining prohealing CD206 and lymphatic vessel endothelial hyaluronic acid receptor 1 (LYVE1)-expressing macrophages. This study highlights the importance of the IL-17 pathway in wound closure offering new possibilities of therapeutic intervention in chronic wounds. [ABSTRACT FROM AUTHOR]

Abstract: Epidermal growth factor receptor (EGFR) mutations identify patients with lung cancer who derive benefit from kinase inhibitors. However, most patients eventually develop resistance, primarily due to the T790M second‐site mutation. Irreversible inhibitors (e.g., osimertinib/AZD9291) inhibit T790M‐EGFR, but several mechanisms, including a third‐site mutation, C797S, confer renewed resistance. We previously reported that a triple mixture of monoclonal antibodies, 3×mAbs, simultaneously targeting EGFR, HER2, and HER3, inhibits T790M‐expressing tumors. We now report that 3×mAbs, including a triplet containing cetuximab and trastuzumab, inhibits C797S‐expressing tumors. Unlike osimertinib, which induces apoptosis, 3×mAbs promotes degradation of the three receptors and induces cellular senescence. Consistent with distinct mechanisms, treatments combining 3×mAbs plus sub‐inhibitory doses of osimertinib synergistically and persistently eliminated tumors. Thus, oligoclonal antibodies, either alone or in combination with kinase inhibitors, might preempt repeated cycles of treatment and rapid emergence of resistance. [ABSTRACT FROM AUTHOR]

Extranodal NK/T-cell lymphoma, nasal type (ENKTL) is a subtype of non-Hodgkin lymphoma with a poor prognosis. Although first-line treatments for patients with localized ENKTL have been established, there is no gold standard treatment for patients with advanced ENKTL and refractory and/or relapsed disease. Anti-CD30 antibody-based therapy, including brentuximab vedotin (BV), has been shown to target malignant lymphomas with CD30 expression. In particular, this therapeutic agent has recently been suggested to be effective for Hodgkin lymphoma and mature T-cell lymphoma. However, the efficacy of BV toward ENKTL has not yet been established. Therefore, we investigated the expression of CD30 in a large cohort to evaluate BV as a potential treatment for ENKTL. In this study, 97 Japanese patients with newly diagnosed ENKTL between January 2007 and December 2015 were enrolled. Flow cytometry and immunohistochemistry were performed for the evaluation of CD30 expression. If the cut-off value of CD30 expression is 1% or more, there were 55 positive cases (56.5%). According to the localization of lesion, the frequency of CD30 expression was significantly higher in the non-nasal type than in the nasal type (P = .0394). No differences were observed in almost all clinical characteristics between CD30-positive cases and CD30-negative cases. In addition, the expression of CD30 was not a prognostic factor for either overall survival or progression-free survival. In conclusion, frequent expression of CD30 in ENKTL suggests anti-CD30 antibody-based therapy may be an effective treatment. [ABSTRACT FROM AUTHOR]

Objective The efficacy of mogamulizumab in adult T-cell leukemia/lymphoma ( ATLL) was reported in a previous phase 2 study. Compared with patients in clinical trials, however, most patients in real-life settings have demonstrated worse outcomes. Method We retrospectively analyzed 96 patients with relapsed/refractory ATLL who received mogamulizumab treatment. Results Relapsed/refractory ATLL patients with a median age of 70 years received a median of five courses of mogamulizumab. Hematologic toxicity and skin rash were the most common adverse events, and both were manageable. Of 96 patients, 87 were evaluable for efficacy. The overall response rate was 36%, and the median progression-free survival ( PFS) and overall survival ( OS) from the start of mogamulizumab therapy were 1.8 and 4.0 months, respectively. Of the original 96 patients, only 25 fulfilled the inclusion criteria of the phase 2 study. Those who met the criteria demonstrated longer median PFS and OS durations of 2.7 and 8.5 months, respectively. The median OS from diagnosis in relapsed/refractory ATLL patients receiving mogamulizumab was 12 months, longer than the 5.8 months in a historical cohort without mogamulizumab. Conclusion In clinical practice, mogamulizumab exhibited antitumor activity in patients with relapsed/refractory ATLL, with an acceptable toxicity profile. Mogamulizumab therapy improved the OS of ATLL patients. [ABSTRACT FROM AUTHOR]

Promising antitumor activities of nivolumab, a fully humanized IgG4 inhibitor antibody against the programmed death-1 protein, were suggested in previous phase 1 studies. The present phase 2, single-arm study ( JAPIC- CTI #111681) evaluated the antitumor activities of nivolumab and explored its predictive correlates in advanced melanoma patients at 11 sites in Japan. Intravenous nivolumab 2 mg/kg was given repeatedly at 3-week intervals to 35 of 37 patients enrolled from December 2011 to May 2012 until they experienced unacceptable toxicity, disease progression, or complete response. Primary endpoint was objective response rate. Serum levels of immune modulators were assessed at multiple time points. As of 21 October 2014, median response duration, median progression-free survival, and median overall survival were 463 days, 169 days, and 18.0 months, respectively. The overall response rate and 1- and 2-year survival rates were 28.6%, 54.3%, and 42.9%, respectively. Thirteen patients remained alive at the end of the observation period and no deaths were drug related. Grade 3-4 drug-related adverse events were observed in 31.4% of patients. Pretreatment serum interferon-γ, and interleukin-6 and -10 levels were significantly higher in the patients with objective tumor responses than in those with tumor progression. In conclusion, giving repeated i.v. nivolumab had potent and durable antitumor effects and a manageable safety profile in advanced melanoma patients, strongly suggesting the usefulness of nivolumab for advanced melanoma and the usefulness of pretreatment serum cytokine profiles as correlates for predicting treatment efficacy. [ABSTRACT FROM AUTHOR]

Neutrophils play an important role in cancer. This does not only relate to the well-established prognostic value of the presence of neutrophils, either in the blood or in tumor tissue, in the context of cancer progression or for the monitoring of therapy, but also to their active role in the progression of cancer. In the current review, we describe what is known in general about the role of neutrophils in cancer. What is emerging is a complex, rather heterogeneous picture with both pro- and anti-tumorigenic roles, which apparently differs with cancer type and disease stage. Furthermore, we will discuss the well-known role of neutrophils as myeloid-derived suppressor cells ( MDSC), and also on the role of neutrophils as important effector cells during antibody therapy in cancer. It is clear that neutrophils contribute substantially to cancer progression in multiple ways, and this includes both direct effects on the cancer cells and indirect effect on the tumor microenvironment. While in many cases neutrophils have been shown to promote tumor progression, for instance by acting as MDSC, there are also protective effects, particularly when antibody immunotherapy is performed. A better understanding of the role of neutrophils is likely to provide opportunities for immunomodulation and for improving the treatment of cancer patients. [ABSTRACT FROM AUTHOR]

Treatment of systemic lupus erythematosus patients with epratuzumab (Emab), a humanized monoclonal antibody targeting CD22, leads to moderately reduced B-cell numbers but does not completely deplete B cells. Emab appears to induce immunomodulation of B cells, but the exact mode of action has not been defined. In the present study, we aimed to understand the effects of Emab on B cells using a humanized mouse model (Huki CD22), in which the B cells express human instead of murine CD22. Emab administration to Huki CD22 mice results in rapid and long-lasting CD22 internalization. There was no influence on B-cell turnover, but B-cell apoptosis ex vivo was increased. Emab administration to Huki CD22 mice had no effect on B-cell numbers in several lymphatic organs, nor in blood. In vitro exposure of B cells from Huki CD22 mice to Emab resulted in decreased B-cell receptor (BCR) induced Ca2+ mobilization, whereas B-cell proliferation after Toll-like receptor (TLR) stimulation was not affected. In addition, IL-10 production was slightly increased after TLR and anti-CD40 stimulation, whereas IL-6 production was unchanged. In conclusion, Emab appears to inhibit BCR signaling in a CD22-dependent fashion without strong influence on B-cell development and B-cell populations. [ABSTRACT FROM AUTHOR]

A new member of the lysyl oxidase (LOX) family, lysyl oxidase-like 4 (LOXL4), is overexpressed in head and neck squamous cell carcinoma (HNSCC) compared to normal squamous epithelium. A monoclonal antibody (mAb) derived from fusion of Balb/c mouse splenocytes immunized with LOXL4 specific peptide was used to evaluate its therapeutic efficacy in 15 HNSCC cell lines associated with LOXL4 overexpression. For xenograft experiments 41 severe combined immunodeficient (SCID) mice were used to analyze LOXL4-mAb mediated tumor regression. Cell viability was analyzed using cytotoxicity-, and clonogenic-assays. Significant suppression of tumor cell growth was observed in 12 out of 15 (80%) tumor cell lines after 48 hr exposure to the mAb (LD50 of 15 µg/ml to 45 µg/ml). The effect induced by the antibody could be blocked by pre-incubation of the antibody with the peptide used for immunization of the mice and antibody generation, indicating that the effect of the antibody is specific. In mice inoculated with HNSCC cells, i.v. injections of the LOXL4-mAb resulted within 70 days in extensive tumor destruction in all treated animals whereas no tumor regression occurred in control animals. In mice pre-immunized i.v. with LOXL4-mAb and subsequently injected with HNSCC cells, tumor development was considerably delayed in contrast to non LOXL4-mAb pre-immunized animals. These results demonstrate that the LOXL4-mAb has potent antitumor activity and suggest its suitability as a therapeutic immune agent applicable to HNSCC exhibiting tumor specific upregulation of LOXL4. [ABSTRACT FROM AUTHOR]

Autologous stem cell transplant (ASCT) can improve outcomes for mantle cell lymphoma (MCL) patients, yet relapses are frequent. We hypothesized that high-dose anti-CD20 radioimmunotherapy (RIT)-based conditioning could improve results in this setting. We thus assessed 162 consecutive patients with MCL at our centre undergoing ASCT following high-dose RIT-based (n = 61) or standard (n = 101) conditioning. RIT patients were less likely to be in first remission (48% vs. 72%; P = 0.002), be in complete remission (CR) (26% vs. 61%; P < 0.001) and have chemosensitive disease (84% vs. 96%; P = 0.006). RIT-based conditioning was associated with a reduced risk of treatment failure [hazard ratio (HR) 0.40; P = 0.001] and mortality (HR 0.49; P = 0.01) after adjusting for these imbalances. This difference increased as disease status worsened (from CR to partial remission to stable/progressive disease), with respective HRs of 1.14, 0.53 and 0.04 for mortality, and 0.66, 0.36 and 0.14 for treatment failure. RIT-based conditioning appears to improve outcome following ASCT for MCL patients unable to achieve CR after controlling for imbalances in important risk factors. These data support the further study of RIT and radiation-based strategies in a risk-adapted approach to ASCT for persistent MCL. [ABSTRACT FROM AUTHOR]

Monoclonal antibody (mAb) immunotherapy is currently experiencing an unprecedented amount of success, delivering blockbuster sales for the pharmaceutical industry. Having experienced several false dawns and overcoming technical issues which limited progress, we are now entering a golden period where mAbs are becoming a mainstay of treatment regimes for diseases ranging from cancer to autoimmunity. In this review, we discuss how these mAbs are most likely working and focus in particular on the key receptors that they interact with to precipitate their therapeutic effects. Although their targets may vary, their engagement with Fcγ receptors (FcγRs) on numerous immune effector cells is almost universal, and here we review their roles in delivering successful immunotherapy. [ABSTRACT FROM AUTHOR]

The article evaluates all aplastic anaemia (AA) and hypoplastic myelodysplastic syndrome (H-MDS) patients who were administered anti-thymocyte globulin (ATG). The main goal of the authors was to determine the platelet count threshold employed before the administration of ATG and related haemorrhages.

This multicentre, randomized, phase II study was conducted to examine whether the addition of mogamulizumab, a humanized anti- CC chemokine receptor 4 antibody, to mLSG15, a dose-intensified chemotherapy, further increases efficacy without compromising safety of patients with newly diagnosed aggressive adult T-cell leukaemia-lymphoma ( ATL). Patients were assigned 1:1 to receive mLSG15 plus mogamulizumab or mLSG15 alone. The primary endpoint was the complete response rate (% CR); secondary endpoints included the overall response rate ( ORR) and safety. The % CR and ORR in the mLSG15-plus-mogamulizumab arm ( n = 29) were 52% [95% confidence interval ( CI), 33-71%] and 86%, respectively; the corresponding values in the mLSG15 arm ( n = 24) were 33% (95% CI, 16-55%) and 75%, respectively. Grade ≥ 3 treatment-emergent adverse events, including anaemia, thrombocytopenia, lymphopenia, leucopenia and decreased appetite, were observed more frequently (≥10% difference) in the mLSG15-plus-mogamulizumab arm. Several adverse events, including skin disorders, cytomegalovirus infection, pyrexia, hyperglycaemia and interstitial lung disease, were observed only in the mLSG15-plus-mogamulizumab arm. Although the combination strategy showed a potentially less favourable safety profile, a higher % CR was achieved, providing the basis for further investigation of this novel treatment for newly diagnosed aggressive ATL. This study was registered at ClinicalTrials.gov, identifier: NCT01173887. [ABSTRACT FROM AUTHOR]

MDX-1097 is an antibody specific for a unique B cell antigen called kappa myeloma antigen ( KMA) that consists of cell membrane-associated free kappa light chain (κ FLC). KMA was detected on kappa human multiple myeloma cell lines (κ HMCLs), on plasma cells ( PCs) from kappa multiple myeloma (κ MM) patients and on κ PC dyscrasia tissue cryosections. In primary κ MM samples, KMA was present on CD38+ cells that were CD138 and CD45 positive and/or negative. MDX-1097 exhibited a higher affinity for KMA compared to κ FLC and the latter did not abrogate binding to KMA. MDX-1097-mediated antibody-dependent cellular cytotoxicity ( ADCC) and in vitro exposure of target cells to the immunomodulatory drug lenalidomide resulted in increased KMA expression and ADCC. Also, in vitro exposure of peripheral blood mononuclear cells ( PBMCs) to lenalidomide enhanced MDX-1097-mediated ADCC. PBMCs obtained from myeloma patients after lenalidomide therapy elicited significantly higher levels of MDX-1097-mediated ADCC than cells obtained prior to lenalidomide treatment. These data establish KMA as a relevant cell surface antigen on MM cells that can be targeted by MDX-1097. The ADCC-inducing capacity of MDX-1097 and its potentiation by lenalidomide provide a powerful rationale for clinical evaluation of MDX-1097 alone and in combination with lenalidomide. [ABSTRACT FROM AUTHOR]

CD20-based monoclonal antibodies have become established as treatments for lymphoma, rheumatoid arthritis, systemic lupus erythematosus, vasculitis and dermatomyositis, with the principle therapeutic mechanism relating to B-cell depletion through effector cell engagement. An article by Brühl et al. in this issue of the European Journal of Immunology [Eur. J. Immunol. 2015. 45: 705-715] reveals a fundamentally distinct mechanism of silencing autoimmune B-cell responses. Rather than B-cell depletion, the authors use anti-CD79b antibodies to induce B-cell tolerance and suppress humoral immune responses against collagen to prevent the development of arthritis in mice. Here we highlight the differences in the mechanisms used by anti-CD20 and anti-CD79b Ab therapy and discuss why depletion of B cells may not be required to treat autoimmune arthritis and other B-cell-associated pathologies. [ABSTRACT FROM AUTHOR]

Despite the significant advances in modern chemotherapy, it remains challenging to treat adult patients with acute lymphoblastic leukaemia ( ALL). The relapse rate remains high, and the outcome at the time of relapse is dismal. Antibody-based therapies have demonstrated promising results in this patient group. Variable mechanisms have been applied to target surface antigens ( CD20 [also termed MS4A1], CD22, CD52 and CD19) that are commonly expressed on malignant leukaemia cells. In this review, we will focus on the clinical application of such therapies in adult ALL, including the naked antibodies: Rituximab, Ofatumumab, Epratuzumab and Alemtuzumab; the immunotoxins: BL22 and Combotox; the immunoconjugates: inotuzumab and SAR 3419; as well as the Bi-specific T cell engaging (Bi TE)-specific antibody, Blinatumomab. [ABSTRACT FROM AUTHOR]

The article presents a study which reveals that Fc gamma receptor IIB decreases efficacy of rituximab monotherapy in treatment of follicular lymphoma (FL). Topics discussed include reduction in half life of antibody due to inhibitory FCGR2B, higher expression level of FCGR2B as compared to cells of FL and possible therapeutic significance of FCGR2B in lymphoid malignancies.

Novel therapies with increased efficacy and decreased toxicity are desperately needed for the treatment of acute myeloid leukaemia ( AML). The anti CD33 immunoconjugate, gemtuzumab ozogamicin ( GO), was withdrawn with concerns over induction mortality and lack of efficacy. However a number of recent trials suggest that, particularly in AML with favourable cytogenetics, GO may improve overall survival. This data and the development of alternative novel monoclonal antibodies (m Ab) have renewed interest in the area. Leukaemic stem cells (LSC) are identified as the subset of AML blasts that reproduces the leukaemic phenotype upon transplantation into immunosuppressed mice. AML relapse may be caused by chemoresistant LSC and this has refocused interest on identifying and targeting antigens specific for LSC. Several mAb have been developed that target LSC effectively in xenogeneic models but only a few have begun clinical evaluation. Antibody engineering may improve the activity of potential new therapeutics for AML. The encouraging results seen with bispecific T cell-engaging mAb-based molecules against CD19 in the treatment of B-cell acute lymphobalstic leukaemia, highlight the potential efficacy of engineered antibodies in the treatment of acute leukaemia. Potent engineered mAb, possibly targeting novel LSC antigens, offer hope for improving the current poor prognosis for AML. [ABSTRACT FROM AUTHOR]

Abstract: It is commonly believed that antibodies are too large (∼150kDa) to access the intracellular compartment. Therefore, therapeutic antibodies have been traditionally used to target cell surface receptors or soluble proteins in the circulation, leaving a large intracellular treasure of potential cancer-specific targets untapped. This review offers new perspectives on our recently proposed concept that antibodies can be used to target intracellular tumor antigens for anti-cancer therapy. We propose to vastly expand the repertoire of potential targets for cancer immunotherapy since many excellent cancer targets are inside cells. [Copyright &y& Elsevier]

CUB‐domain‐containing‐protein‐1 (CDCP1) is an integral membrane protein whose expression is up‐regulated in various cancer types. Although high CDCP1 expression has been correlated with poor prognosis in lung, breast, pancreas, and renal cancer, its functional role in tumor formation or progression is incompletely understood. So far it has remained unclear, whether CDCP1 is a useful target for antibody therapy of cancer and what could be a desired mode of action for a therapeutically useful antibody. To shed light on these questions, we have investigated the cellular effects of a therapeutic antibody candidate (RG7287). In focus formation assays, prolonged RG7287 treatment prevented the loss of contact inhibition caused by co‐transformation of NIH3T3 cells with CDCP1 and Src. In a xenograft study, MCF7 cells stably overexpressing CDCP1 reached the predefined tumor volume faster than the parental MCF7 cells lacking endogenous CDCP1. This tumor growth advantage was abolished by RG7287 treatment. In vitro, RG7287 induced rapid tyrosine phosphorylation of CDCP1 by Src, which was accompanied by translocation of CDCP1 to a Triton X‐100 insoluble fraction of the plasma membrane. Triggering these effects required bivalency of the antibody suggesting that it involves CDCP1 dimerization or clustering. However, this initial activation of CDCP1 was only transient and prolonged RG7287 treatment induced internalization and down‐regulation of CDCP1 in different cancer cell lines. Antibody stimulated CDCP1 degradation required Src activity and was proteasome dependent. Also in three different xenograft models with endogenous CDCP1 expression RG7287 treatment resulted in significant tumor growth inhibition concomitant with substantially reduced CDCP1 levels as judged by immunohistochemistry and Western blotting. Thus, despite transiently activating CDCP1 signaling, the RG7287 antibody has a therapeutically useful mode of action. Highlights: Antibody RG7287 induces CDCP1 clustering, tyrosine phosphorylation and downregulation.RG7287 blocks transformation of NIH3T3 cells induced by Src and CDCP1 co‐transduction.Stable overexpression of CDCP1 in MCF7 cells leads to faster growing xenograft tumors.RG7287 treatment inhibits tumor growth in three different xenograft models. [ABSTRACT FROM AUTHOR]

The impact of first-line treatment with the anti- CD 20 chimeric monoclonal antibody rituximab in patients with warm-antibody reactive autoimmune haemolytic anaemia ( WAIHA) is unknown. We report the first randomized study of 64 patients with newly diagnosed WAIHA who received prednisolone and rituximab combined ( N = 32) or prednisolone monotherapy ( N = 32). After 12 months, a satisfactory response was observed in 75% of the patients treated with rituximab and prednisolone but in a significantly smaller proportion (36%) of those given prednisolone alone ( P = 0·003). Furthermore, relapse-free survival was significantly better after the combined therapy than after prednisolone monotherapy ( P = 0·02). After 36 months, about 70% of the patients were still in remission in the rituximab-prednisolone group, whereas only about 45% were still in complete or partial remission in the prednisolone group. There was no significant difference between the two groups regarding adverse reactions to the studied medications. Likewise, serious adverse events were equally distributed, and no allergic reactions to rituximab were recorded. In conclusion, our data show that using rituximab and prednisolone combined rather than prednisolone alone as first-line treatment in WAIHA increases both the rate and the duration of the response. [ABSTRACT FROM AUTHOR]

FLT3-ITD mutations are prevalent mutations in acute myeloid leukaemia (AML). PRL-3, a metastasis-associated phosphatase, is a downstream target of FLT3-ITD. This study investigates the regulation and function of PRL-3 in leukaemia cell lines and AML patients associated with FLT3-ITD mutations. PRL-3 expression is upregulated by the FLT3-STAT5 signalling pathway in leukaemia cells, leading an activation of AP-1 transcription factors via ERK and JNK pathways. PRL-3-depleted AML cells showed a significant decrease in cell growth. Clinically, high PRL-3 mRNA expression was associated with FLT3-ITD mutations in four independent AML datasets with 1158 patients. Multivariable Cox-regression analysis on our Cohort 1 with 221 patients identified PRL-3 as a novel prognostic marker independent of other clinical parameters. Kaplan-Meier analysis showed high PRL-3 mRNA expression was significantly associated with poorer survival among 491 patients with normal karyotype. Targeting PRL-3 reversed the oncogenic effects in FLT3-ITD AML models in vitro and in vivo. Herein, we suggest that PRL-3 could serve as a prognostic marker to predict poorer survival and as a promising novel therapeutic target for AML patients. [ABSTRACT FROM AUTHOR]

Currently all approved anti-cancer therapeutic monoclonal antibodies (mAbs) are of the IgG isotype, which rely on Fcgamma receptors (FcγRs) to recruit cellular effector functions. In vitro studies showed that targeting of FcαRI (CD89) by bispecific antibodies (bsAbs) or recombinant IgA resulted in more effective elimination of tumour cells by myeloid effector cells than targeting of FcγR. Here we studied the in vivo anti-tumour activity of IgA EGFR antibodies generated using the variable sequences of the chimeric EGFR antibody cetuximab. Using FcαRI transgenic mice, we demonstrated significant in vivo anti-tumour activity of IgA2 EGFR against A431 cells in peritoneal and lung xenograft models, as well as against B16F10-EGFR cells in a lung metastasis model in immunocompetent mice. IgA2 EGFR was more effective than cetuximab in a short-term syngeneic peritoneal model using EGFR-transfected Ba/F3 target cells. The in vivo cytotoxic activity of IgA2 EGFR was mediated by macrophages and was significantly decreased in the absence of FcαRI. These results support the potential of targeting FcαRI for effective antibody therapy of cancer. [ABSTRACT FROM AUTHOR]

The article focuses on a study related to effect of immune stimulator lenalidomide (L) and alemtuzumab (A) on refractory chronic lymphocytic leukemia (CLL). It informs about the study in which patient was given the combination of L and A where in A reduces natural killer cells and T cells whereas L stimulates T cells and prevents opportunistic infection.

Integrins play a role in tumor growth and metastasis. However, the effect of integrin inhibition has not been visualized on single cancer cells in vivo. In this study, we used a powerful subcellular in vivo imaging model to demonstrate how an anti-integrin antibody affects seeding and growth of osteosarcoma cells on the lung. The 143B human osteosarcoma cell line, expressing red fluorescent protein (RFP) in the cytoplasm and green fluorescent protein (GFP) in the nucleus, was established. Such double-labeled cells enable imaging of apoptosis and mitosis and other nuclear-cytoplasmic dynamics. Using the double-labeled osteosarcoma cells, single cancer-cell seeding in the lung after i.v. injection of osteosarcoma cells was imaged. The anti-β1 integrin monoclonal antibody, AIIB2, greatly inhibited the seeding of cancer cells on the lung (experimental metastasis) while a control antibody had no effect. To image the efficacy of the anti-integrin antibody on spontaneous metastasis, mice with orthotopically-growing 143B-RFP cells in the tibia were also treated with AIIB2 or control anti-rat IgG1 antibody. After 3 weeks treatment, mice were sacrificed and primary tumors and lung metastases were evaluated with fluorescence imaging. AIIB2 significantly inhibited spontaneous lung metastasis but not primary tumor growth, possibly due to inhibition of lung seeding of the cancer cells as imaged in the experimental metastasis study. AIIB2 treatment also increased survival of mice with orthotopically growing 143B-RFP. [ABSTRACT FROM AUTHOR]

Monoclonal antibodies (mAbs) and tyrosine kinase inhibitors targeting the epidermal growth factor receptor (EGFR), which is often pathogenetically overexpressed or mutated in epithelial malignancies and glioma, have been modestly successful, with some approved for human use. MAb 806 was raised against de2–7EGFR (or EGFRvIII), a constitutively active mutation expressed in gliomas, but also recognizes a subset (<10%) of wild-type (wt) EGFR when it is activated by autocrine loop, overexpression or mutation. It does not bind inactive EGFR in normal tissues like liver. Glioma xenografts expressing the de2–7EGFR treated with mAb 806 show reduced receptor autophosphorylation, increased p27KIP1 and reduced cell proliferation. Xenografts expressing the wtEGFR activated by overexpression or autocrine ligand are also inhibited by mAb 806, but the mechanism of inhibition has been difficult to elucidate, especially because mAb 806 does not prevent wtEGFR phosphorylation or downstream signalling in vitro. Thus, we examined the effects of mAb 806 on A431 xenograft angiogenesis. MAb 806 increases vascular endothelial growth factor (VEGF) and interleukin-8 production by activating NF-κB and normalizes tumour vasculature. Pharmacological inhibition of NF-κB completely abrogated mAb 806 activity, demonstrating that NF-κB activation is necessary for its anti-tumour function in xenografts. Given the increase in VEGF, we combined mAb 806 with bevacizumab in vivo, resulting in additive activity. [ABSTRACT FROM AUTHOR]

Horse anti-thymocyte globulin (h-ATG) and ciclosporin are the initial therapy for most patients with severe aplastic anaemia (SAA), but there is no practical and reliable method to predict response to this treatment. To determine whether pretreatment blood counts discriminate patients with SAA who have a higher likelihood of haematological response at 6 months to immunosuppressive therapy (IST), we conducted a single institution retrospective analysis on 316 SAA patients treated with h-ATG-based IST from 1989 to 2005. In multivariate analysis, younger age, higher baseline absolute reticulocyte count (ARC), and absolute lymphocyte count (ALC) were highly predictive of response at 6 months. Patients with baseline ARC ≥ 25 × 109/l and ALC ≥ 1 × 109/l had a much greater probability of response at 6 months following IST compared to those with lower ARC and ALC (83% vs. 41%, respectively; P < 0·001). This higher likelihood of response translated to greater rate of 5-year survival in patients in the high ARC/ALC group (92%) compared to those with a low ARC/ALC (53%). In the era of IST, the baseline ARC and ALC together serve as a simple predictor of response following IST, which should guide in risk stratification among patients with SAA. [ABSTRACT FROM AUTHOR]

Alemtuzumab has shown considerable activity in untreated and relapsed chronic lymphocytic leukaemia. We report our long-term experience in 21 patients within a randomized phase III trial investigating the role of alemtuzumab for consolidation therapy after first-line fludarabine ± cyclophosphamide, which was stopped prematurely due to severe infections. However, after a median follow-up of 48 months, progression-free survival was significantly prolonged for patients receiving alemtuzumab consolidation compared to those with no further treatment ( P = 0·004). Minimal residual disease (MRD) levels were persistently reduced after consolidation. Therefore, despite toxicity, MRD reduction by alemtuzumab consolidation translates into a significantly improved long-term clinical outcome. [ABSTRACT FROM AUTHOR]

Molecular genetic analysis adds important information for lymphoma biology and classification, but the latter is challenged by recent improvement of combined chemo-immunotherapy. In aggressive lymphoma, molecular profiling identifies risk groups with certain genetic background but still the International Prognostic Index (IPI) remains the most important clinically applicable predictor of outcome. In follicular lymphoma (FL), the importance of the meshwork of bystander cells becomes increasingly evident. As combined immuno-chemotherapy improved the prognosis of the patients, several clinical trials indicated that the FLIPI still efficiently discriminates patients at risk for transformation and relapse, although several mechanisms of transformation seem to exist. In mantle cell lymphoma it has been proven that pathogenesis and prognosis mainly depend on deregulation of the cell cycle. A reliable clinical risk score could be established. [ABSTRACT FROM AUTHOR]

We evaluated the dose requirements for sustained in vivo activity of ofatumumab, a human anti-CD20 antibody under development for the treatment of B cell-mediated diseases. In a mouse xenograft model, a single dose, resulting in an initial plasma antibody concentration of 5 μg/ml, which was expected to result in full target saturation, effectively inhibited human B-cell tumour development. Tumour growth resumed when plasma concentrations dropped below levels that are expected to result in half-maximal saturation. Notably, tumour load significantly impacted antibody pharmacokinetics. In monkeys, initial depletion of circulating and tissue residing B cells required relatively high-dose levels. Re-population of B-cell compartments, however, only became detectable when ofatumumab levels dropped below 10 μg/ml. We conclude that, once saturation of CD20 throughout the body has been reached by high initial dosing, plasma concentrations that maintain target saturation on circulating cells (5–10 μg/ml) are probably sufficient for sustained biological activity. These observations may provide a rationale for establishing dosing schedules for maintenance immunotherapy following initial depletion of CD20 positive (tumour) cells. [ABSTRACT FROM AUTHOR]

CD19 and CD21 (CR2) are co-receptors found on B-cells and various B-cell lymphomas, including non-Hodgkin lymphoma. To evaluate their suitability as targets for therapy of such lymphomas using internalization-dependent antibody-drug conjugates [such as antibody-4-( N-maleimidomethyl)cyclohexane-1-carboxylate, ( N2′-deacetyl- N2′-(3-mercapto-1-oxopropyl)-maytansine) (MCC-DM1) conjugates, which require lysosomal degradation of the antibody moiety for efficacy], we examined uptake of antibodies to CD19 and CD21 in a panel of B-cell lines. Anti-CD21 antibodies were not sufficiently internalized even in the highest CD21-expressing Raji cells, resulting in lack of efficacy with anti-CD21-MCC-DM1 conjugates. Anti-CD19 antibody uptake was variable, and was unexpectedly negatively correlated with CD21 expression. Thus, high CD21-expressing Raji, ARH77 and primary B-cells only very slowly internalized anti-CD19 antibodies, while CD21-negative or low expressing cells, including Ramos and Daudi, rapidly internalized these antibodies in clathrin-coated vesicles followed by lysosomal delivery. Anti-CD19-MCC-DM1 caused greater cytotoxicity in the faster anti-CD19-internalizing cell lines, implying that the rate of lysosomal delivery and subsequent drug release is important. Furthermore, transfection of Ramos cells with CD21 impeded anti-CD19 uptake and decreased anti-CD19-MCC-DM1 efficacy, suggesting that CD21-negative tumours should respond better to such anti-CD19 conjugates. This may have possible clinical implications, as anti-CD21 immunohistochemistry revealed only approximately 30% of 54 diffuse large B-cell lymphoma patients lack CD21 expression. [ABSTRACT FROM AUTHOR]

The article presents medical research that found therapy with anti-γ-glutamyl transpeptidase antibody attenuates osteolysis in mice with collagen-induced arthritis. γ-glutamyl transpeptidase (GGT) functions as a bone-resorbtion factor that stimulates the formation of osteoclasts. Immunohistochemistry and real time polymerase chain reaction (RT-PCR) were used to determine GGT expression.