CD38 Expression Levels Research Articles

P681: EUROFLOW STANDARDIZATION TECHNIQUE AND NORMALIZATION PROCEDURES IN LONGITUDINAL FLOW CYTOMETRIC EXPRESSION ANALYSIS OF CD20 IN CLL PATIENTS RECEIVING ANTI-CD20 DIRECTED THERAPY

Background: CD20 expression is still a controversial issue regarding its prognostic value for therapy outcome. While up to 50% of patients relapse within four of years after anti-CD20 directed treatment and constitute a need for a salvage or relapse/refractory treatment, only few publications address the longterm influence on CD20 expression assessed by flow cytometry. The technical complexity of the method and factors affecting the variability of measurements of samples at different time points and from different sources/patients are well recognized by the field and addressed by different approaches as standardization of instruments, automated gating and alignment of population or normalization. Aims: In order to evaluate long term influence of anti-CD20 directed therapy on CD20 expression in patients with chronic lymphocytic leukemia who showed only weak MRD responsiveness to therapy in different clinical trials, we aimed to establish a normalization approach based on the instrument standardization to reduce the proportion of technical variance within data. Methods: Mean fluorescence intensities (MFI) of peak seven of standardized fluorescence beads from daily quality control and instrument standardization of flow cytometers according to the EuroFlow protocol were used to establish a normalization approach. Proof of prinicple was performed using the residual peaks covering the MFI range provided by the beads. To assess different sources of variance ANOVA of a 3x3x3 experiment evaluating marker expressions on different cell populations in the blood of healthy donors using Quantibrite-PE beads was performed addressing technical variation (day, instrument) and biological variation. CD20 and CD19 MFI on CLL cells were retrospectively assessed from MRD measurements of peripheral blood samples of patients enrolled in the phase II GCLLSG trials CLL2-BIG (n=57), -BAG (n=58), -BIO (n=58), -BCG (n=22), combining facultative Bendamustin (B) debulking with either Obinutuzumab (G), Ofatumumab (O), Venetoclax (A), Ibrutinib (I) or Idelalisib (C). Results: Long term shifts of fluorescence intensities, and coefficients of variation were reduced 2 to 10 times across the MFI range covered by the fluorescence beads without distorting the longitudinal course of instrument performance. Most of the variance in assessments of molecules equivalent soluble fluorochrome from MFIs of NK cell and B cell markers in peripheral blood of healthy donors were related to inter-donor variations (p<0.002). Normalized MFIs for CD19 and CD20 on CLL cells do not significantly differ from the measured values in the Mann-Whitney-U test (p>0.85). Higher CD20 expression at therapy start seems to be correlated to strong MRD response solely in the CLL2-BIO trial (p=0.036, Fig. 1). Prognostic factors TP53-, IGHV-, and NOTCH1- mutation did not seem to correlate with the observed CD20 expression differences. Therapy strata showed differences (statistically not significant) in the proportion of firstline and r/r treated patients. Figure 1 Pre-treatment CD20 MFI on CLL cells of patients categorized according to treatment and variable (strong, medium, weak, and no) MRD response. Image:Summary/Conclusion: Following standardized staining and instrument monitoring, it should be possible to robustly assess longitudinal biological variations of marker expression based on MFI values. In a cross trial comparison Obinutzumab showed highest proportion of patients with strong MRD response independent from initial CD20 expression, whereas strong response to Ofatumumab seems to correlate with higher CD20 expression levels.

Co-Culture of THP-1 Cells and Normal Human Epidermal Keratinocytes (NHEK) for Modified Human Cell Line Activation Test (h-CLAT)

To improve the accuracy of skin sensitization prediction of chemicals by conventional alternative methods using cells, it is important to reproduce the environment of skin in vitro, such as the crosstalk between keratinocytes and dendritic cells (DCs). We developed a skin sensitization test system based on the markers and criteria of the human cell line activation test (h-CLAT), which combines THP-1 cells as a surrogate for DCs and keratinized normal human epidermal keratinocytes (NHEK). After exposure to chemicals via keratinized NHEK, the cell surface expression of CD54 and CD86 on THP-1 was measured by flow cytometry. This co-culture system evaluated 2,4-dinitrochlorobenzene (DNCB), a typical sensitizer, as positive, lactic acid (LA), a non-sensitizer, as negative, and isoeugenol (IE), a prohapten that requires biological activation to acquire skin sensitization, as positive. However, the expression levels of CD54 and CD86 in DNCB-treated THP-1 were lower than those in normal h-CLAT. Therefore, we investigated the effects of the medium and secretion by NHEK cells on THP-1 cells. CD54 and CD86 expression was enhanced in monocultured THP-1 in the medium for keratinized NHEK and in the conditioned medium of keratinized NHEK. The increase in CD54 and CD86 by changes in the medium type was higher than that by the NHEK secretion; therefore, it was found that the medium composition has a large effect on the evaluation index among the experimental parameters in the co-culture system. It is necessary to find the optimal medium for immunotoxicity assessment in the co-culture system.

Abstract 5352: Genome-wide CRISPR-cas9 screening identifies KDM6A as a modulator of CD38 expression in multiple myeloma: Therapeutic implications

Abstract Daratumumab (Dara) is the first-in-class monoclonal antibody targeting CD38 which triggers both direct and immune mediated cytotoxicity in preclinical in vitro and in vivo models of multiple myeloma (MM) in the bone marrow (BM) milieu. Importantly, Dara combination therapies can achieve high frequency and extent of response in both relapsed/refractory and newly diagnosed MM. However, relapse of MM is commonly observed due, at least in part, to downregulation of CD38 on MM cells. Here we utilize genome-wide CRISPR-cas9 knockout (KO) screening to identify novel regulators mediating CD38 expression and Dara sensitivity in MM cells. We identified 46 different sgRNAs to be positively correlated with MM cytotoxicity triggered by Dara and NK cells treatment. We further performed second round screening using the cell population with lowest 5% CD38 expression after CRISPR lentiviral library transduction. Importantly, KDM6A was the top ranked of the overlapping genes from these two screenings. Next, we individually KO of KDM6A in MM cells and found that both mRNA and protein levels of CD38 were significantly decreased, as well as the cell surface CD38 expression detected by flow cytometry. Re-introduction of KDM6A into KDM6A KO cells restored the expression level of CD38 and Dara-induced cytotoxicity, indicating that KDM6A positively regulates CD38 expression in MM cells. Since KDM6A regulates demethylation of lysine 27 at histone H3 (H3K27) to activate gene expression, we next examined whether CD38 expression was altered by methylation status of H3K27. From our ChIP-seq and ChIP Q-PCR data, we identified that H3K27me3 level was highly enriched on the promotor area of CD38 in KDM6A KO cells compared to control cells. These data indicate that KDM6A modulates CD38 expression by regulating H3K27me3 level on the CD38 promotor, thereby mediating sensitivity of MM cells to Dara-induced cytotoxicity. H3K27me3 is regulated by the balance of demethylase (KDM6A) and methyltransferase (EZH2). However, downregulating H3K27me3 on the CD38 promoter by enhancing KDM6A activity is challenging. Therefore, we next explored whether EZH2 inhibitor can restore CD38 expression and overcome Dara resistance in KDM6A KO cells. Indeed, H3K27me3 level on the CD38 promotor area was significantly decreased by EZH2 inhibitor. Moreover, EZH2 inhibitor treatment upregulated both CD38 mRNA and protein levels in KDM6A KO cells. Importantly, EZH2 inhibitor also restored sensitivity of KDM6A KO cells to Dara-mediated NK cell cytotoxicity. Taken together, our studies demonstrate that KDM6A regulates H3K27me3 level on CD38 promotor area and CD38 expression in MM. Moreover, we validate that combination treatment with EZH2 inhibitor and Dara can overcome Dara resistance in preclinical MM models, providing the rationale for combination clinical trials to overcome Dara resistance and improve patient outcome. Citation Format: Jiye Liu, Lijie Xing, Teru Hideshima, Kenneth Carl Anderson. Genome-wide CRISPR-cas9 screening identifies KDM6A as a modulator of CD38 expression in multiple myeloma: Therapeutic implications [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5352.

Abstract 4179: High valency of IGM-2323, a CD20xCD3 IgM bispecific T cell engager, displaces rituximab binding and induces potent B lymphoma cell killing

Abstract Rituximab-containing treatment regimens are the standard of care for patients with non-Hodgkin’s lymphoma (NHL). However, the majority of patients ultimately experience disease relapse or progression indicating resistance to rituximab therapy. IGM-2323 is an engineered high-affinity, high-avidity anti-CD20 pentameric IgM antibody with an anti-CD3 scFv fused to the joining chain. IGM-2323 offers a novel treatment strategy in NHL through two mechanisms: 1) the recruitment of T cells to kill CD20-expressing tumor cells through T cell dependent cellular cytotoxicity (TDCC) and, 2) complement-dependent cytotoxicity (CDC). We evaluated the activity of IGM-2323 in the presence of rituximab since rituximab can persist in patients after treatment discontinuation, and it can bind to an overlapping epitope on CD20 as IGM-2323. We hypothesized that the high valency of IGM-2323 could displace rituximab, thus enabling potent B cell killing by IGM-2323 even in the presence of high concentrations of rituximab. The affinity of IGM-2323 and its corresponding bivalent anti-CD20 IgG antibody to recombinant human CD20 protein were measured by surface plasmon resonance. IGM-2323 bound to human CD20 with an apparent 300-fold higher binding affinity (KD) and ~100-fold slower off-rate (kdis) than the bivalent anti-CD20 IgG. Human B cell lines with a range of CD20 expression levels, including a CD20-low rituximab-resistant Ramos cell variant, were pre-treated with escalating concentrations of rituximab, and subsequently evaluated in vitro for cell binding, TDCC, and CDC by IGM-2323. At high concentrations of rituximab, which correspond to reported peak serum concentrations (Cmax) found in rituximab-treated patients, IGM-2323 displaced the binding of rituximab on human B cell lines. In contrast, binding of a bispecific CD20xCD3 IgG was severely inhibited by the Cmax of rituximab. In TDCC assays with healthy donor effector T cells, pre-treatment with high concentrations of rituximab only modestly inhibited IGM-2323 activity. Furthermore, only a minor impact to the maximum killing activity (Emax) of IGM-2323 was observed at the Cmax of rituximab. In contrast, rituximab pre-treatment resulted in a distinctly lower Emax of a bispecific CD20xCD3 IgG. Live cell imaging of CDC kinetics was utilized to quantify the extent of CDC by IGM-2323 with or without rituximab. Pre-treatment with rituximab enhanced CDC of IGM-2323 compared to single agent activity. Our preclinical data indicate that IGM-2323 maintains activity in the presence of rituximab. IGM-2323 is currently being studied in a phase 1 clinical trial in relapsed/refractory NHL, where it has been generally well tolerated, with both complete and partial responses observed (NCT04082936). Clinical studies will continue to evaluate these findings, including the treatment of patients with circulating serum levels of rituximab. Citation Format: Kevin C. Hart, Kathryn Logronio, Mandy Li, Poonam Yakkundi, Marigold Manlusoc, Keyu Li, Paul R. Hinton, Dean Ng, Maya K. Leabman, Genevive Hernandez, Thomas Manley, Angus M. Sinclair, Stephen F. Carroll, Bruce A. Keyt, Maya F. Kotturi. High valency of IGM-2323, a CD20xCD3 IgM bispecific T cell engager, displaces rituximab binding and induces potent B lymphoma cell killing [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 4179.

99mTc-CD3813: A Nanobody-Based Single Photon Emission Computed Tomography Radiotracer with Clinical Potential for Myeloma Imaging and Evaluation of CD38 Expression.

Daratumumab (DARA) is an anti-CD38 monoclonal antibody for the treatment of multiple myeloma (MM). The tumor CD38 expression level is one of the important factors in determining the efficacy of DARA treatment. Therefore, there is an urgent clinical need for a noninvasive tool to evaluate the CD38 levels in cancer patients before, during, and after DARA treatment. In this study, we prepared a new molecular imaging probe 99mTc-CD3813, the 99mTc-labeled nanobody CD3813, for noninvasive imaging of CD38 expression by single photon emission computed tomography (SPECT). We evaluated 99mTc-CD3813 for its CD38 affinity and specificity and its capacity to image the CD38 expression in the MM and lymphoma xenografts models. 99mTc-CD3813 SPECT/CT is able to visualize subcutaneous/orthotopic myeloma lesions in animal models and has advantages over 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography. Excess DARA has less impact on its tumor uptake (3.14 ± 0.83 vs 2.29 ± 0.91 %ID/g, n.s.), strongly suggesting that there is no competition between 99mTc-CD3813 and DARA in binding to CD38. 99mTc-CD3813 SPECT/CT revealed significant reduction in CD38 expression in the Ramos-bearing mice under DARA treatment, as evidenced by their reduced tumor uptake (3.04 ± 0.70 vs 1.07 ± 0.28 %ID/cc, P < 0.001). 99mTc-CD3813 SPECT/CT was also able to detect the increased tumor uptake (0.79 ± 0.29 vs 2.12 ± 0.12 %ID/cc, P < 0.001) due to the upregulation of CD38 levels caused by all-trans retinoic acid infection. 99mTc-CD3813 is a promising SPECT radiotracer for imaging the CD38-positive tumors and has clinical potential as a molecular imaging tool for evaluation of the CD38 expression level in patients before, during, and after DARA treatment.

The prognostic effect on childhood acute lymphoblastic leukemia of CD34+CD38− expressed in leukemia cells

ABSTRACT Objective Acute lymphoblastic leukemia is the most common malignant disease in children. CD34 and CD38 are expressed in both normal and leukemia cells, but studies of their prognostic associations in childhood acute lymphoblastic leukemia are limited. The aim of this study was to investigate the prognostic effect of CD34 + CD38− leukemia cells in this childhood cancer. Methods From January 2014 to January 2019, children with newly diagnosed acute lymphoblastic leukemia were included in this study and followed up until July 2020. The participants were divided into CD34+ and CD34− groups according to CD34 expression level at diagnosis, and the CD34+ group was further divided into CD34 + CD38− and CD34 + CD38+ subgroups based on CD38 expression level. We tracked clinical biological features, therapeutic outcomes, and other patient data for comparisons. Results The OS and EFS did not differ significantly between the CD34+ and CD34− groups (both P > 0.05). CD34+CD38- group and CD34+CD38+ group were further compared. OS differed significantly between these two groups (χ2 = 3.89, P = 0.048), as did the recurrence rate (χ2 = 5.04, P = 0.025), but EFS did not (χ2 = 1.45, P > 0.05). Survival analysis in patients with recurrence showed a significantly higher OS for the CD34 + CD38+ group compared with the CD34 + CD38− group (χ2 = 5.08, P = 0.024). The CD34+CD38- group and CD34+CD38+ group were matched for propensity scores. When recurrence was compared in the two groups after matching, the difference was statistically significant (P < 0.001). Conclusion CD34+ and CD34− expression does not differ by prognosis in children with acute lymphoblastic leukemia, but CD34 + CD38− may indicate a poor prognosis.

Regulation of T cell CD5 levels by BTLA

Abstract Many coinhibitory receptors are absent from naïve T cells and upregulated upon activation. In contrast, there are a small number of coinhibitory receptors expressed constitutively by naïve T cells, including CD5, BTLA, and VISTA. The relationship between these constitutively expressed coinhibitors is unknown. We examined the relationship between the constitutively expressed BTLA and CD5 in T cell ontogeny. We found an inverse relationship between CD5 and BTLA expression levels, with low BTLA expression in the thymus and higher BTLA expression in the periphery, corresponding with high and low CD5 expression, respectively. To determine if there is a causal relationship between BTLA expression and CD5 expression, we examined CD5 expression in wild type (WT) vs. btla−/− T cells. Interestingly, btla−/− T cells consistently expressed higher levels of CD5 both in thymic and splenic CD4 and CD8 T cells, indicating that BTLA expression directly or indirectly determines the level of CD5 expression broadly across T cells. In contrast, the loss of an inducible coinhibitor, PD-1, only affected CD5 levels on splenic CD8+ T cells. The loss of BTLA expression early in ontogeny might alter the TCR repertoire indirectly affecting CD5 levels, or instead its loss might affect CD5 expression rapidly within mature T cells. To examine the latter, we deleted btla by administering tamoxifen to adult btlafl/fl CreERT2+/− mice and WT CreERT2+/− controls. Loss of btla in adults led only to a transiently heightened CD5 expression. Together our data indicates that loss of BTLA early, but not later in ontogeny, leads to a long-term increase in CD5 expression by T cells. Such calibration of CD5 levels early in ontogeny might serve to reduce autoimmunity. Funded by the CIHR, NSERC, and an AAI fellowship; btlafl/fl mice provided by the La Jolla Institute for Immunology.

Effect of CD38 on B-cell function and its role in the diagnosis and treatment of B-cell-related diseases.

CD38 is a multifunctional receptor and enzyme present on the surface of B lymphocytes, which can induce B lymphocytes proliferation and apoptosis by crosslinking related cytokines to affect the function of B cells, thus affecting immune regulation in humans and promoting tumorigenesis. The level of CD38 expression in B cells has become an important factor in the clinical diagnosis, treatment, and prognosis of malignant tumors and other related diseases. Therefore, studying the relationship between CD38 expression on the surface of B cells and the occurrence of the disease is of great significance for elucidating its association with disease pathogenesis and the clinical targeted therapy. In this paper, we review the effects of CD38 on B-cell activation, proliferation, and differentiation, and elaborate the functional role and mechanism of CD38 expression on B cells. We also summarize the relationship between the level of CD38 expression on the surface of B cells and the diagnosis, treatment, and prognosis of various diseases, as well as the potential use of targeted CD38 treatment for related diseases. This will provide an important theoretical basis for the scientific research and clinical diagnosis and treatment of B-cell-related diseases.

Exploring a peptide nucleic acid-based antisense approach for CD5 targeting in chronic lymphocytic leukemia.

We herein report an innovative antisense approach based on Peptide Nucleic Acids (PNAs) to down-modulate CD5 expression levels in chronic lymphocytic leukemia (CLL). Using bioinformatics tools, we selected a 12-mer tract of the CD5 mRNA as the molecular target and synthesized the complementary and control PNA strands bearing a serine phosphate dipeptide tail to enhance their water solubility and bioavailability. The specific recognition of the 12-mer DNA strand, corresponding to the target mRNA sequence by the complementary PNA strand, was confirmed by non-denaturing polyacrylamide gel electrophoresis, thermal difference spectroscopy, circular dichroism (CD), and CD melting studies. Cytofluorimetric assays and real-time PCR analysis demonstrated the downregulation of CD5 expression due to incubation with the anti-CD5 PNA at RNA and protein levels in Jurkat cell line and peripheral blood mononuclear cells from B-CLL patients. Interestingly, we also observed that transfection with the anti-CD5 PNA increases apoptotic response induced by fludarabine in B-CLL cells. The herein reported results suggest that PNAs could represent a potential candidate for the development of antisense therapeutic agents in CLL.

CD38: A Significant Regulator of Macrophage Function.

Cluster of differentiation 38 (CD38) is a cell surface glycoprotein and multifunctional extracellular enzyme. As a NADase, CD38 produces adenosine through the adenosine energy pathway to cause immunosuppression. As a cell surface receptor, CD38 is necessary for immune cell activation and proliferation. The aggregation and polarization of macrophages are affected by the knockout of CD38. Intracellular NAD+ levels are reduced by nuclear receptor liver X receptor-alpha (LXR) agonists in a CD38-dependent manner, thereby reducing the infection of macrophages. Previous studies suggested that CD38 plays an important role in the regulation of macrophage function. Therefore, as a new marker of macrophages, the effect of CD38 on macrophage proliferation, polarization and function; its possible mechanism; the relationship between the expression level of CD38 on macrophage surfaces and disease diagnosis, treatment, etc; and the role of targeting CD38 in macrophage-related diseases are reviewed in this paper to provide a theoretical basis for a comprehensive understanding of the relationship between CD38 and macrophages.

Bryostatin Activates CAR T-Cell Antigen-Non-Specific Killing (CTAK), and CAR-T NK-Like Killing for Pre-B ALL, While Blocking Cytolysis of a Burkitt Lymphoma Cell Line.

The advent of CAR-T cell therapy has changed the face of clinical care for relapsed and refractory pre-B-acute lymphocytic leukemia (B-ALL) and lymphoma. Although curative responses are reported, long-term cures remain below 50%. Different CAR T-cell leukemia targets appear to have different mechanisms of CAR-T escape. For CD22, therapeutic evasion is linked to down-modulation of the number CD22 proteins expressed on the extracellular aspect of the leukemia cell plasma membrane. Recently, pharmacologic agents known to induce cellular differentiation or epigenetic modification of leukemia have been shown to impact CD22 and CD19 expression levels on B-ALL, and thereby increase sensitivity to CAR-T mediated cytolysis. We explored the impact of epigenetic modifiers and differentiation agents on leukemia cell lines of B cell origin, as well as normal B cells. We confirmed the activity of bryostatin to increase CD22 expression on model cell lines. However, bryostatin does not change CD22 levels on normal B cells. Furthermore, bryostatin inhibited CAR-T mediated cytolysis of the Raji Burkitt lymphoma cell line. Bryostatin increased the cytolysis by CD22 CAR-T for B-ALL cell lines by at least three mechanisms: 1) the previously reported increase in CD22 target cell numbers on the cell surface, 2) the induction of NK ligands, and 3) the induction of ligands that sensitize leukemia cells to activated T cell antigen-non-specific killing. The opposite effect was seen for Burkitt lymphoma, which arises from a more mature B cell lineage. These findings should caution investigators against a universal application of agents shown to increase killing of leukemia target cells by CAR-T in a specific disease class, and highlights that activation of non-CAR-mediated killing by activated T cells may play a significant role in the control of disease. We have termed the killing of leukemia targets, by a set of cell-surface receptors that does not overlap with NK-like killing “CTAK,” CAR-T Cell antigen-non-specific killing.

Targeting CD33 for acute myeloid leukemia therapy

BackgroundThe aim of this study was to analyze the level of CD33 expression in patients with newly diagnosed AML and determine its correlation with clinical characteristics.MethodsSamples were collected for analysis from AML patients at diagnosis. We evaluated the level of CD33 expression by flow cytometry analysis of bone marrow. Chi-square or t- tests were used to assess the association between the high and low CD33 expression groups. Survival curves were generated by the Kaplan-Meier and Cox regression model method.ResultsIn this study we evaluated the level of CD33 expression in de novo patients diagnosed from November 2013 until January 2019. The mean value of 73.4% was used as the cutoff for the two groups. Statistical analysis revealed that 53 of the 86 (61.2%) AML patients were above the mean. Although there was no statistical significance between CD33 expression level and gene mutation, FLT3 mutation (P = 0.002) and NPM1 mutation (P = 0.001) were more likely to be seen in the high CD33 group. The overall survival (OS) was worse in the high CD33 group (39.0 m vs. 16.7 m, x2 = 13.06, P < 0.001). The Cox survival regression display that the CD33 is independent prognostic marker (HR =0.233,p = 0.008). Univariate analysis showed that the high expression of CD33 was an unfavorable prognostic factor. Of the 86 patients, CD33-high was closely related to the patients with normal karyotype (x2 = 4.891,P = 0.027), high white blood cell count (WBC, t = 2.804, P = 0.007), and a high ratio of primitive cells (t = 2.851, P = 0.005).ConclusionsThese findings provide a strong rationale for targeting CD33 in combination with chemotherapy, which can be considered a promising therapeutic strategy for AML.

Prediction of Tumor-Infiltrating CD20+ B-Cells in Patients with Pancreatic Ductal Adenocarcinoma Using a Multilayer Perceptron Network Classifier Based on Non-contrast MRI

Conventional chemotherapy has limited benefit in pancreatic ductal adenocarcinoma (PDAC), necessitating identification of novel therapeutic targets. Radiomics may enable non-invasive prediction of CD20 expression, a hypothesized therapeutic target in PDAC. To develop a machine learning classifier based on noncontrast magnetic resonance imaging for predicting CD20 expression in PDAC. Retrospective study was conducted on preoperative noncontrast magnetic resonance imaging of 156 patients with pathologically confirmed PDAC from January 2017 to April 2018. For each patient, 1409 radiomics features were selected using minimum absolute contraction and selective operator logistic regression algorithms. CD20 expression was quantified using immunohistochemistry. A multilayer perceptron network classifier was developed using the training and validation set. A log-rank test showed that the CD20-high group (22.37 months, 95% CI: 19.10-25.65) had significantly longer survival than the CD20-low group (14.9 months, 95% CI: 10.96-18.84). The predictive model showed good differentiation in training (area under the curve [AUC], 0.79) and validation (AUC, 0.79) sets. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 73.21%, 75.47%, 0.74, 0.76, and 0.73, respectively, for the training set and 69.23%, 80.95%, 0.74, 0.82, and 0.68, respectively, for the validation set. Multilayer perceptron classifier based on noncontrast magnetic resonance imaging scanning can predict the level of CD20 expression in PDAC patients.

Immunohistochemical analysis of CD68, CD4, CD8 and CD20 expression in cervical dysplasia and its relationship with HR-HPV infection.

The aim of the study was to examine the composition of the inflammatory infiltrates in cervical premalignant lesions and contribute to a better understanding of immune response to HR-HPV infection and dysplasia. Semi-quantitative analysis of CD68, CD4, CD8 and CD20 immunohistochemical expression in a series of 41 cervical biopsies without dysplasia, 24 cases of LSIL and 35 HSIL cases was performed. In each subject, genotyping for 12 HR-HPV types was done prior to the biopsy. Observing the total sample, no correlation between CD68, CD4, CD8 and CD20 expression levels and HR-HPV infection was found, regardless of the presence of mono- or co-infection (p>0.05). A statistically significant correlation between dysplastic changes and CD68 expression, as well as between dysplastic changes and CD4 expression, was observed (p=0.003 and p=0.016, respectively). For CD68 expression, there was a positive correlation with both LSIL and HSIL, and concerning CD4 expression, there was a positive correlation primarily with LSIL. The finding of mild CD68 expression shows a 10.5 times greater chance of the sample being classified as LSIL, while the finding of a strong CD68 expression shows a 12 times greater chance of the sample being classified as HSIL, in comparison to cases with no expression. When the samples were stratified in relation to the lesion grade, a correlation between HR-HPV infection and CD68/CD4 expression again was not proved (p>0.05). No correlation between CD8 and CD20 expression with dysplasia was found (p>0.05). We consider a higher prevalence of macrophages and CD4 lymphocytes in dysplastic lesions to be a response to dysplasia rather than HR-HPV infection itself. The increase of the expression levels of macrophages with the degree of the lesion speaks in favour of their potential role in the progression of the neoplastic process.

Targeting CD38 in acute myeloid leukemia interferes with leukemia trafficking and induces phagocytosis

Targeting the interaction between leukemic cells and the microenvironment is an appealing approach to enhance the therapeutic efficacy in acute myeloid leukemia (AML). AML infiltration induces a significant release of inflammatory cytokines in the human bone marrow niche which accelerates leukemogenesis. As the transmembrane glycoprotein CD38 has been shown to regulate cytokine release, we assessed the anti-leukemic potential of CD38 inhibition in AML. CD38 expression in AML cells proved to depend on microenvironmental cues and could be significantly enforced through addition of tretinoin. In fact, the anti-CD38 antibody daratumumab showed significant cytostatic efficacy in a 3D in vitro triple-culture model of AML, but with modest cell-autonomous cytotoxic activity and independent of CD38 expression level. In line with a predominantly microenvironment-mediated activity of daratumumab in AML, CD38 inhibition significantly induced antibody-dependent phagocytosis and showed interference with AML cell trafficking in vivo in a xenograft transplantation model, but overall lacked robust anti-leukemic effects.

Efficient Targeting of CD38 in Mature T-Cell Neoplasms with Daratumumab and Allogeneic NK Cells

Introduction: Mature T-cell neoplasms (MTCN) are a heterogeneous and aggressive group of lymphoid neoplasms with very limited options for precision immunotherapy. Targeted immunotherapy with antibodies directed against surface markers on tumor cells has emerged as an effective treatment for B-cell neoplasms, but the development of immunotherapy strategies for MTCN has been much slower. CD38 is expressed at low levels in a subset of normal resting T-cells. Data on the frequency and level of CD38 expression is MTCN are lacking. Our goal was to study the expression and stability of CD38 on a spectrum of neoplastic T-cell populations and assess the potential anti-tumor effect of anti-CD38 monoclonal antibodies in combination with allogeneic natural killer (NK) cells in MTCN.Methods and results: We searched the Thomas Jefferson University Hospital (TJUH) pathology records for all cases of MTCN for which immune-phenotypical characterization of the neoplastic T-cell population by multi-color flow cytometry (FC) was available. CD38 expression was evaluated in cases where an abnormal T-cell population (defined as loss of one on more pan T-cell markers and/or a skewed CD4 to CD8 ratio). A total of 103 unique patients with MTCN were identified. Of these, 51 had at least one biopsy whereby tumor cells had an abnormal immunophenotype which could then be assessed for CD38 expression. CD38 was expressed to some extent in all but 2 cases with expression levels on peripheral T-cell lymphoma-not other specified (PTCL-NOS)(% Mean±SEM = 80.84±10.26, N=11), angioimmunoblastic T-cell lymphoma (AITL) (% Mean±SEM = 80.56±7.34, N=6), nodal PTCL with T follicular-helper (T FH) phenotype (% Mean±SEM = 55.00±12.72, N=7), anaplastic large cell lymphoma (ALCL) (% Mean±SEM = 77.38±10.75, N=3), large granular lymphocytic leukemia (LGLL) (% Mean±SEM = 80.27±7.49, N=4), T-cell prolymphocytic leukemia (T-PLL) (% Mean±SEM = 88.26±4.20, N=7), cutaneous T-cell lymphoma (CTCL) (% Mean±SEM = 49.52±14.77, N=7), adult T‐cell leukemia/lymphoma (ATLL) (% Mean±SEM = 76.68±10.45, N=3), hepatosplenic T-cell lymphoma/monomorphic epitheliotropic intestinal T-cell lymphoma (HSTCL/MEITL) (% Mean±SEM = 75.00±11.37, N=3). The medians and ranges of the MFI of CD38 on CD38+ tumor cells were the following: PTCL-NOS 29.46 (3.1-115.62), AITL 13.64 (2.67-29.41), other PTCL-T FH 5.87 (0-48.67), ALCL 11.13 (3.6-11.28), LGL (13.52 (9.72-18.25), T-PLL 6.49 (3.09-18), CTCL 8.36 (0-116.75), ATLL 27.17 (3.54-60.5), HSTCL/MEITL 15.96 (6.96-167.85). We also measured surface expression of CD38 on the patient-derived MTCN cell lines HuT-78, HuT-102, Jurkat, H9, HH, and MOTN1, all of which expressed CD38, to determine which of these cell lines could be used for in vitro experiments. We next evaluated if the CD38 molecule is an effective target for antibody-mediated therapy in MTCN, by testing the ability of daratumumab (dara) to enhance antibody-dependent cellular cytotoxicity (ADCC) elicited by NK cells. For this, we purified normal NK-cells from TJUH Blood Bank leukoreduction filters and cultured with recombinant IL-15 for 48 hours prior to all experiment. T-cell lines and primary MTCN cells were treated with increasing concentrations (0.1 µg/mL - 2 µg/mL) of dara or isotype control. NK-cells were added at Effector:Target ratio of 5:1 and incubated for 4 hours at 37⁰ Celsius. Cytotoxicity was measured by LDH release assay. Dara induced significant cell lysis starting at doses as low as 0.1μg/mL in both T-cell lines and primary MTCN cells, reaching maximum cytotoxicity at 0.5-2μg/mL (mean±SEM cytotoxicity in isotype vs dara treated cells= 50.0±5.05% vs 97.5±2.5%, N=4, p-value=0.0002). The degree of ADCC induction also correlated with interferon-gamma (IFN-g) release by NK cells in vitro for both T-cell lines and primary MTCN cells.Conclusions: The majority of MTCN analyzed (N=49, 96%) showed any degree of CD38 expression by FC with a wide variation of intensity, including within the same subtype. Allogeneic NK cells efficiently elicited dara-mediated ADCC of tumor cells from all MTCN subtypes and produced abundant IFN-g. These data highlight the potential of targeting CD38 in MTCN with anti-CD38 antibodies and allogeneic NK cells. The strong CD38 expression observed in most tumor cells from ultra-rare and very aggressive subtypes of MTCL opens the door to much needed new treatment strategies. DisclosuresBrammer: Celgene: Research Funding; Kymera Therapeutics: Consultancy; Seattle Genetics: Speakers Bureau. Chakravarti: Kiadis Pharma: Patents & Royalties. Porcu: Viracta: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Innate Pharma: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BeiGene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Research Funding; Daiichi: Honoraria, Research Funding; Kiowa: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Spectrum: Consultancy; DrenBio: Consultancy.

Frontline Brentuximab Vedotin Plus Cyclophosphamide, Doxorubicin and Prednisone in Patients with Peripheral T-Cell Lymphoma with Less Than 10% CD30 Expression (SGN35-032, Trial in Progress)

BackgroundBrentuximab vedotin (BV) was the first antibody-drug conjugate to be approved in multiple cancer types (Gauzy-Lazo 2020). The combination of a CD30-directed monoclonal antibody, a protease-cleavable linker, and the microtubule-disrupting agent monomethyl auristatin E drives the anticancer activity of BV by inducing CD30-targeted cell cycle arrest and apoptosis as well as the bystander effect on adjacent cells (Sutherland 2006, Hansen 2016, Schönberger 2018).In the ECHELON-2 phase 3 clinical trial, BV, cyclophosphamide, doxorubicin, and prednisone (A+CHP) showed efficacy in patients with peripheral T-cell lymphoma (PTCL) across a range of CD30 expression levels, including the lowest eligible level of 10% by immunohistochemistry when compared with patients treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) (Advani 2019).It is hypothesized that A+CHP will demonstrate efficacy in PTCL with <10% CD30 expression because i) clinical responses to BV have occurred in patients with PTCL, cutaneous T-cell lymphoma, or B-cell lymphoma with low (<10%) and undetectable CD30 expression (Jagadeesh 2019) and ii) CD30 expression levels were not predictive of A+CHP responses in non-systemic anaplastic large cell lymphoma (sALCL) (Advani 2019).Study Design and MethodsSGN35-032 is a dual-cohort, open-label, multicenter, phase 2 clinical trial (NCT04569032) designed to evaluate the efficacy and safety of A+CHP in patients with non-sALCL PTCL and CD30 expression of <10% on tumor cells. Up to approximately 40 patients will be enrolled in each of the CD30-negative (expression <1%) and the CD30-low (expression ≥1% to <10%) cohorts. Patients will be enrolled based on local results but only patients with CD30 expression <10% per central confirmation will be analyzed for the primary and secondary endpoints. Patients will receive 21-day cycles of A+CHP for 6-8 cycles.Key inclusion criteria include adults with newly diagnosed PTCL, excluding sALCL, per the World Health Organization 2016 classification; CD30 expression <10% by local assessment; and fluorodeoxyglucose-avid disease by positron emission tomography (PET) and measurable disease of at least 1.5 cm by computed tomography (CT), as assessed by the site radiologist. Patients with previous exposure to BV or doxorubicin will not be eligible.The primary endpoint of this trial is objective response rate (ORR) per blinded independent central review (BICR) using the Revised Response Criteria for Malignant Lymphoma (Cheson 2007). Secondary endpoints include ORR by BICR using the modified Lugano criteria (Cheson 2014), complete response rate, progression-free survival (PFS), and duration of response per BICR using the Revised Response Criteria for Malignant Lymphoma (Cheson 2007), overall survival, and safety and tolerability. A PET scan is required at baseline, after Cycle 4, and after the completion of study treatment. Follow-up restaging CT scans will be performed over the next 2 years.In both the CD30-negative and the CD30-low cohorts, efficacy and safety endpoints will be summarized using descriptive statistics to describe continuous variables by cohort. Time-to-event endpoints, such as PFS, will be estimated using Kaplan-Meier (KM) methodology and KM plots will be presented. Medians for time-to-event analyses (e.g., median PFS) will be presented and two-sided 95% confidence intervals will be calculated using the log-log transformation method.Enrollment is planned for 15 US sites and 32 sites across the Czech Republic, France, Italy, and the UK. DisclosuresKnowles: Seagen Inc.: Current Employment. Horwitz: ADC Therapeutics, Affimed, Aileron, Celgene, Daiichi Sankyo, Forty Seven, Inc., Kyowa Hakko Kirin, Millennium /Takeda, Seattle Genetics, Trillium Therapeutics, and Verastem/SecuraBio.: Consultancy, Research Funding; Affimed: Research Funding; Aileron: Research Funding; Acrotech Biopharma, Affimed, ADC Therapeutics, Astex, Merck, Portola Pharma, C4 Therapeutics, Celgene, Janssen, Kura Oncology, Kyowa Hakko Kirin, Myeloid Therapeutics, ONO Pharmaceuticals, Seattle Genetics, Shoreline Biosciences, Inc, Takeda, Trillium Th: Consultancy; Celgene: Research Funding; C4 Therapeutics: Consultancy; Crispr Therapeutics: Research Funding; Daiichi Sankyo: Research Funding; Forty Seven, Inc.: Research Funding; Kura Oncology: Consultancy; Kyowa Hakko Kirin: Consultancy, Research Funding; Millennium/Takeda: Research Funding; Myeloid Therapeutics: Consultancy; ONO Pharmaceuticals: Consultancy; Seattle Genetics: Consultancy, Research Funding; Secura Bio: Consultancy; Shoreline Biosciences, Inc.: Consultancy; Takeda: Consultancy; Trillium Therapeutics: Consultancy, Research Funding; Tubulis: Consultancy; Verastem/Securabio: Research Funding.

Clinical Significance of Prolymphocytes in Chinese Patients with Chronic Lymphocytic Leukemia

IntroductionChronic lymphocytic leukemia(CLL), characterized by monoclonal CD5+ B cells appearing in blood, marrow and lymphoid tissues, is the most common chronic leukemia in western countries. Until now CLL remains incurable with a heterogeneous clinical course, some patients developing progression rapidly while the others presenting a relatively indolent course. It has been reported that higher percentage of prolymphocytes was associated with increasing refractoriness to treatment and worse prognosis. In this study we were trying to explore the effect of prolymphocytes on the prognosis of CLL.MethodsTwo hundred and fifty-one treatment naïve CLL patients in Jiangsu Province Hospital were retrospectively enrolled in our study from April 2014 to November 2019. The median time from diagnosis to peripheral-blood smear examination was 0.13 month and median follow-up time was 30.87 months.A total of 200 lymphocytes and prolymphocytes were counted. The percentage of prolymphocytes was collected. Basic clinical characteristics and other prognostic markers including age, sex, Rai and Binet stage, B2-microglobulin(B2MG), lactate dehydrogenase(LDH) level, CD38 and ZAP70 expression level, hemoglobulin(HB), platelets count(PLT), absolute lymphocyte count(ALC), thymidine kinase-1(TK-1), albumin(ALB), IGHV mutation status and TP53 status were also put in the analysis. The time to first treatment(TTFT)was defined as the time from sampling to first treatment and the overall survival(OS) time was the time from sampling to death.An X-tile analysis provided the optimal prolymphocyte cutoff point. Wilcoxon rank sum test was used to compare the distribution of prolymphocytes percentage in different subgroups. The Kaplan-Meier method was used to construct the survival curves and the log-rank test was used to compare the difference. Multivariate analysis was conducted based on the Cox-regression model. All tests were two-sided and P<0.05 was considered to be statistically significant. Statistical analysis was performed with SPSS (version 26.0; IBM Corporation, Chicago, IL) and survival curves was drawn with GraphPad Prism (version 9.0: GraphPad Software, Inc., La Jolla, CA, USA).ResultsAmong 252 patients, most of them were male(67.7%) and 35.9% were older than 65 years old. We found significantly different distribution of prolymphocytes percentage in patients with different B2MG, Rai stage, LDH, CD38 expression, TK1, IGHV mutation status and TP53 status(Table 1). The optimal cutoff of prolymphocytes percentage provided by X-tile analysis was 1%. Then all the patients were divided into two groups based on the prolymphocytes percentage and obvious survival difference between the two groups was shown in both TTFT(P<0.001) and OS(P=0.005)(Figure 1). Age, Rai stage, Binet stage, B2MG, LDH, ALC, ALB, IGHV mutation status and prolymphocytes percentage were further included in a multivariate analysis in which, however, prolymphocytes percentage didn't show an independent prognostic effect on TTFT(P=0.370, HR=1.209(0.798-1.833)) or OS(P=0.391, HR=1.604(0.545-4.721)).DiscussionIn this study we found the optimal cutoff of prolymphocytes percentage was 1% which is different with previous study(Oscier et al. 2016). That may be due to that we choose TTFT as the endpoint. Besides, about prolymphocytes percentage was not statistically significant in multivariate analysis, we guess that may be attributed to that the sample was too little or there were only Chinese patients in our cohort. In conclusion, prolymphocytes percentage has certain prognostic significance in CLL patients and we think multivariate analysis would be different after we expanded our cohort. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

A High Sensitivity aCD22 CAR Combined with aCD19 CAR to Generate Dual Targeting CAR T Cells for the Treatment of r/r B-ALL

Background:Anti-CD19 CAR treatment has shown a remarkable response in r/r B-ALL patients, however, a major cause for relapse following CAR administration is the loss of the CD19 antigen. CD22 is a promising alternative target for B-ALL malignancies, although generating an effective CAR to CD22 is challenging due to the size, density and rigidity of this ligand. Furthermore, in the B-ALL setting the CD22 expression levels are known to down regulate in response to selective CAR pressure. This resulted in patients relapsing with lower CD22 density post-treatment (2,839 epitopes/cell) presumably due to the target density falling below the sensitivity threshold for the aCD22 CAR 1. In this study we aim to improve CAR efficacy for the treatment of r/r B-ALL by firstly developing a highly sensitive aCD22 CAR capable of targeting cells that express less than 1000 CD22 molecules per cell. Secondly, we combined this new aCD22 CAR with an aCD19 CAR to generate a dual targeting CD19 and CD22 product via co-transduction for the treatment of paediatric r/r B-ALL as part of an extension cohort of the CARPALL clinical trial (NCT02443831).Results:We screened 18 anti-CD22 binders with a range of affinities (1-36.5nM) and binding epitopes in CAR format for high functional sensitivity to low density targets. We filtered binders for their ability to maintain cytotoxicity, proliferation and cytokine release with low expressing CD22 targets. We identified the optimal aCD22 binder (9A8) which when combined in a CAR structure containing a 41BBz endodomain was capable of lysing target cells transduced to express less than 255 CD22 mols/cell while not affecting CD22 negative targets. Similar to the previously tested aCD22 binder M971, our new 9A8 binder also targets the membrane proximal Ig domain of the CD22 molecule. However unlike M971, 9A8 utilises a conventional 16 amino acid linker between the heavy and light chain to form the scFv and has a lower propensity to tonically signal compared to the M971 CAR. To generate a dual CD19 and CD22 targeting product, the 9A8 aCD22 CAR was co-transduced with the aCD19 CAT19 CAR vector (AUTO1) utilised in the CARPALL clinical trial for the treatment of paediatric r/r B-ALL. In a NSG animal model engrafted with WT CD19+/CD22+ Nalm-6 cells, the dual targeting co-transduced T cells (AUTO1/22) were significantly better at supressing tumour growth compared to single targeting AUTO1 CAR T cells (Figure 1). Furthermore, CAR T cells recovered from these animals showed an equal persistence of both aCD19 CAR and aCD22 CAR. In an effort to recapitulate the loss of CD19 target observed in aCD19 CAR relapsed patients, we challenged our transduced T cells in a CD19-knockout Nalm-6 NSG model (Figure 1). In this setting, single transduced AUTO1 CAR T cells were unable to control tumour growth above the non-transduced T cell controls. In contrast, the dual targeting co-transduced AUTO1/22 CAR T cells significantly supressed tumour growth and showed enrichment of CAR T cells expressing the aCD22 9A8 CAR in the bone marrow.The dual targeting co-transduced AUTO1/22 is currently being evaluated in an extension cohort of the CARPALL clinical trial (NCT02443831) for the treatment of paediatric r/r B-ALL.Conclusion:We engineered a highly sensitive aCD22 9A8 CAR which when combined with the aCD19 CAT19 CAR allows for improved in vivo function and the targeting of CD19 negative, CD22 positive cells. The use of these dual targeting T cells may reduce the incidence of CD19 negative relapses in the r/r B-ALL setting.1. Fry TJ, Shah NN, Orentas RJ, et al. CD22-targeted CAR T cells induce remission in B-ALL that is naive or resistant to CD19-targeted CAR immunotherapy. Nat. Med. 2018;24(1):20-28. [Display omitted] DisclosuresKokalaki: Autolus Ltd: Current Employment. Grothier: Autolus Ltd: Ended employment in the past 24 months. Manzoor: Autolus Ltd: Ended employment in the past 24 months. Costu: Autolus Ltd: Ended employment in the past 24 months. Srivastava: Autolus Ltd: Current Employment. Jha: Autolus Ltd: Current Employment. Gealy: Autolus Ltd: Current Employment. Stanczuk: Autolus Ltd: Ended employment in the past 24 months. Robson: Autolus Ltd: Current Employment. Taylor: Autolus Ltd: Current Employment. El-Kholy: Autolus Ltd: Current Employment. Baldan: Autolus Ltd: Current Employment. Righi: Autolus Ltd: Current Employment. Sillibourne: Autolus Ltd: Current Employment. Onuoha: Autolus: Ended employment in the past 24 months. Ghorashian: UCLB: Patents & Royalties; Novartis: Honoraria. Cordoba: Autolus Ltd: Current Employment. Amrolia: ADC Therapeutics: Other: Named inventor on a patent which is being transferred to ADCT.; Autolus: Patents & Royalties. Pule: Autolus Ltd: Current Employment.

CD38 x ICAM1 Bispecific Antibody Is a Novel Approach for Treating Multiple Myeloma and Lymphoma

Targeting cluster of differentiation 38 (CD38) with monoclonal antibodies has resulted in outstanding responses in patients with multiple myeloma (MM). However, a significant portion of patients failed to respond and nearly all patients eventually relapsed. Furthermore, daratumumab, an anti-CD38 antibody, only showed limited monotherapy activity in relapsed/refractory Non-Hodgkin lymphoma (NHL) patients in a phase 2 study. One of the mechanisms of resistance has been partially attributed to lower CD38 expression. Intercellular adhesion molecule 1 (ICAM1), an immunoglobulin (Ig)-like cell adhesion molecule, is highly expressed in multiple myeloma and lymphoma. Antibody against ICAM1, bersanlimab (BI505, BioInvent), was well-tolerated, but only showed limited clinical efficacy in MM patients. Here, we generated bispecific CD38 x ICAM1 antibody to target ICAM1 + tumor types with low to medium CD38 expression. RNA sequencing (RNAseq) results from the Cancer Cell Line Encyclopedia (CCLE) database showed that ICAM1 is highly expressed on myeloma and lymphoma cell lines. ICAM1 expression levels for selected myeloma and lymphoma cell lines were then validated using flow cytometry. The CD38 x ICAM1 bispecific antibody was constructed by paring a novel CD38 antibody and a novel ICAM1 antibody through an asymmetric three chain knob-into-hole format. The bispecific antibody showed potent in vitro antibody-dependent cellular cytotoxicity (ADCC) activities on ICAM1 + tumor cells with medium to low CD38 levels, where daratumumab has low or minimal effect. The bispecific antibody also showed potent in vitro antibody-dependent cellular phagocytosis (ADCP) activities on cell lines with a range of CD38 expression. The CD38 x ICAM1 bispecific antibody further demonstrated potent tumor inhibition activities in in vivo myeloma and lymphoma cell line-derived xenograft (CDX) models, including cell lines with low to medium CD38 expression. We then evaluated CD38 and ICAM1 expressions in lymphoma patient-derived xenograft (PDX) samples by RNAseq. Among the 37 PDX samples, 27 of them showed ICAM1 expression above 2 5 fragments per kilobase of transcript per million map reads (FPKM). On the contrary, there is a wide range of CD38 expression levels with only 6 samples having CD38 expression above 2 5 FPKM. The ICAM1 and CD38 expressions in the selected PDX samples were further validated with IHC staining. Most importantly, the CD38 x ICAM1 bispecific antibody showed complete tumor inhibition in a rituximab-resistant lymphoma PDX model, whereas daratumumab only showed minimal efficacy. In conclusion, the CD38 x ICAM1 bispecific antibody demonstrated improved efficacy and specificity toward CD38 + and ICAM1 + tumor cells and represents a novel approach for treating multiple myeloma and lymphoma. DisclosuresNo relevant conflicts of interest to declare.