anti-CD20 Antibody Research Articles

Early Rituximab versus Escalating Therapy in Neuromyelitis Optica: A Cost and Quality of Life Analysis

Introduction: Rituximab, an anti-CD20 monoclonal antibody, has shown effectiveness in reducing disease relapses and disability accrual through relapses in patients with neuromyelitis optica spectrum disorders (NMOSD). However, its higher cost compared to oral immunosuppressants raises questions about its cost-effectiveness, particularly in low and middle-income countries. This study aimed to compare the cost-effectiveness of early rituximab treatment versus escalation treatment in NMOSD patients. Methods: We conducted a retrospective study of NMOSD patients treated with rituximab in the first five years of disease at a hospital in São Paulo, Brazil, from 2015 to 2019. The Early Group consisted of NMOSD patients who received rituximab as a first-line treatment. The Escalating Therapy Group included patients who were prescribed rituximab after experiencing disease activity while on oral immunosuppressants, primarily azathioprine. An economic model based on Expanded Disability Status Score (EDSS) transitions was used to assess cost-effectiveness. Cost and utility data were derived from previous studies, and sensitivity analyses for different willingness to pay (WTP) thresholds and percentage of patients upscaling from oral immunossupressants to rituximab were performed. Results: Thirty NMOSD patients were included. In the Early Group, the proportion of patients reaching the highest EDSS states (6.5 or more) decreased over five years compared to baseline. In contrast, the Escalating Therapy Group experienced an increase in this proportion over the same period. Cost-effectiveness was achieved for willingness to pay (WTP) of €20-80,000 in our main analysis, sustained in our sensitivity analysis. Conclusion: Early treatment with rituximab has the potential to lower healthcare costs and enhance quality of life for NMOSD patients, supporting its early prescription for preventive treatment.

Clinical Relevance of Intensive Laboratory Monitoring With Standard Venetoclax Ramp-Up for Chronic Lymphocytic Leukemia: A Real-World Experience

PURPOSE Venetoclax is the standard of care for chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) but requires intensive monitoring for optimal safety. Clinical relevance of intensive monitoring in practice is unknown, especially for patients with low or intermediate risk for tumor lysis syndrome (TLS). PATIENTS AND METHODS A retrospective review was conducted to determine clinical significance of monitoring for TLS during standard ramp-up for patients with CLL/SLL. Patients receiving abbreviated ramp-up, clinical trials, or concurrent Bruton tyrosine kinase inhibitors were excluded. The primary end point was TLS incidence, with secondary end points describing associated clinical interventions. RESULTS Fifty-five patients met study criteria. The majority of patients received venetoclax as first-line therapy (58%), with anti-CD20 antibody therapy (82%), and were at low risk of TLS (75%). No clinical TLS events occurred, whereas laboratory TLS occurred in only 1.8% of patients. No patients required antihyperuricemic therapy, and few interventions for hyperphosphatemia or hypocalcemia (3.6% of patients) were required. Additional intravenous fluids were uncommonly required (1.8% of patients), and no unplanned hospitalizations were required. CONCLUSION These findings support efforts to reduce intensive monitoring requirements during venetoclax ramp-up for patients with CLL, potentially increasing accessibility of venetoclax.

Measurable residual disease-driven treatment in first-line chronic lymphocytic leukaemia.

The therapeutic paradigm for patients suffering from chronic lymphocytic leukaemia continues to rapidly evolve. Fixed duration therapies continue to develop using novel-novel non-chemotherapeutic combinations. B-cell lymphoma 2 (BCL2) inhibitors in combination with either anti-CD20 antibody or Bruton tyrosine kinase inhibitors are able to achieve deep responses. Levels of attained 'negative' measurable residual disease (MRD, also known as minimal residual disease) have been shown to predict survival outcomes in a number of settings, including following immunochemotherapy and BCL2-combinations. This review will outline the current data supporting fixed duration treatment approaches, the use of MRD in clinical practice, alongside the challenges and possibilities for MRD utility in the future.

CNSC-60. SYNERGISTIC IMMUNOMODULATION THROUGH DUAL ANTIBODY THERAPY TARGETING CD47 AND CD24 FOR ENHANCED ANTITUMOR IMMUNITY IN GLIOBLASTOMA

Abstract Tumor cell phagocytosis by antigen-presenting cells (APCs) plays a pivotal role in fostering antitumor immunity. However, glioblastoma, known for its evasive strategies, exploits key phagocytosis checkpoints, including CD47, CD24, and beta-2-microglobulin. While mono-treatment targeting CD47 blockade has shown some antitumor responses in glioma, prolonged tumor-suppressing ability and significant extension of survival remain elusive. In this study, we combine anti-CD47 and anti-CD24 antibody treatments, unveiling a synergistic effect in promoting tumor cell phagocytosis. This enhanced phagocytosis profile triggers the activation of the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway in APCs, thereby facilitating efficient T cell priming. This orchestrated interplay between innate and adaptive antitumor immunity not only attenuates glioblastoma growth and extends overall survival. These findings illuminate a promising avenue for harnessing phagocytosis modulation as a strategic approach to treat challenging tumors equipped with multiple immune checkpoints.

EXTH-40. IMMUNOPHENOTYPING OF RWTC-MBTA AUTOLOGOUS CANCER VACCINE IN PRECLINICAL GLIOBLASTOMA MODELS

Abstract Despite advances in immunotherapy, glioblastoma multiforme (GBM) remains challenging to treat due to its low inherent immunogenicity and a suppressive tumor microenvironment. Converting “cold” GBMs to “hot” tumors is crucial for effective immune activation and improved patient outcomes. We comprehensively characterized the rWTC-MBTA autologous cancer vaccine, consisting of Mannan-BAM-anchored irradiated whole tumor cells, Toll-like receptor ligands (LTA, Poly(I:C), R-848), and an anti-CD40 agonistic antibody, in preclinical GL261 and SB28 GBM models. A substantial number of vaccinated mice exhibited complete regression of GBM tumors in a T-cell-dependent manner, with no significant toxicity. Long-term tumor-specific immune memory was confirmed upon tumor rechallenge. In the vaccine-draining lymph nodes of the SB28 model, rWTC-MBTA vaccination triggered a major rise in cDC1 12 hours post-treatment, followed by an increase in cDC2, moDC, and pDC on Days 5 and 13. Enhanced cytotoxicity of CD4+ and CD8+ T cells in vaccinated mice was verified in co-culture with tumor cells. Comprehensive immunophenotyping in the GL261 and SB28 GBM microenvironments confirmed decreased regulatory T cells and increased CD4+ and CD8+ T cell infiltration in vaccinated mice. T-cell exhaustion analyses revealed an increase in the Tim3+CD8+ T cells. No significant differences were observed in the quantification of M-MDSC and PMN-MDSC between control and vaccinated mice, but PD-L1 expression significantly increased in M2 macrophages in vaccinated mice. Our findings demonstrate that rWTC-MBTA induces potent and long-term adaptive immune responses against GBM, warranting further investigation of combinations with other immunotherapies for enhanced efficacy.

Phase 1 study of isatuximab monotherapy in Chinese patients with relapsed/refractory multiple myeloma.

In this multi-center, Phase-1 study (NCT03733717), we characterized the pharmacokinetics (PK) of the anti-CD38 antibody isatuximab (Isa) after IV administration (primary objective), and evaluated safety, immunogenicity, and preliminary anti-myeloma activity in Chinese patients with relapsed/refractory multiple myeloma (RRMM). Isa 20-mg/kg was administered weekly (QW) in cycle 1, then biweekly (Q2W). Twenty-one extensively pretreated RRMM patients (median 4 prior lines; 95.2% refractory to last regimen), received ≥ 1 dose of Isa. After first IV-infusion, mean maximum observed concentration was 402μg/mL and mean area-under-the-concentration-versus-time curve (first 1-week dosing interval) 37,000μg·h/mL. After repeated administration, exposure (Ctrough) increased 3.11-folds (day 1/cycle 2) versus first administration (day 8/cycle 1). Safety findings were consistent with the known Isa safety profile, with no new safety signals. Any-causality, grade ≥ 3 treatment-emergent adverse events (TEAEs) were reported in 47.6% of patients. Serious, treatment-related AEs occurred in 2 patients. Isa treatment was generally well tolerated; only 1 patient discontinued due to TEAE. Preliminary efficacy results showed a 19.0% overall response rate (clinical benefit, 33.3%). Our results demonstrate a PK profile for Isa comparable to prior findings in Western and other East-Asian populations, as well as safety and tolerability of treatment with IV Isa 20-mg/kg QW-Q2W in Chinese RRMM patients.Trial registration: The trial was registered with ClinicalTrials.gov; NCT03733717. Date of first trial registration: 07/11/2018.

IMMU-61. THE LAST OF US: A FUNGI BASED DENDRITIC CELL VACCINE

Abstract BACKGROUND Glioblastoma (GBM) is the most prevalent primary malignant brain tumor in adults. The current standard treatment for newly diagnosed GBM involves maximal surgical resection followed by radiotherapy and temozolomide. Despite these interventions, the median overall survival for GBM patients remains approximately 15 months, highlighting the critical need for innovative therapeutic approaches. OBJECTIVE Our laboratory has previously developed a subcutaneous autologous tumor vaccine incorporating irradiated (IR) tumor cells with phagocytosis-stimulating ligands (Mannan-BAM), toll-like receptor (TLR) agonists, and an immunostimulant anti-CD40 antibody (collectively termed MBT). This combination has shown efficacy in mouse models of colon carcinoma, breast cancer, melanoma, and, more recently, gliomas. Our study aimed to create a dendritic cell (DC) vaccine using this strategy. METHODS To evaluate whether MBT could induce the maturation of DCs in vitro, we harvested BMDCs from mice and co-cultured them in the presence of MBT-tagged irradiated tumor cells. We then analyzed the maturation markers using flow cytometry and assessed cytokine production via ELISA. To test the efficacy of this approach in vivo, we utilized two different murine glioma models (SB28 and GL261). RESULTS Using flow cytometry, we observed a significant upregulation of important co-stimulatory molecules. Additionally, ELISA analysis demonstrated that MBT-treated DCs significantly increased the secretion of Type 1 cytokines while limiting the secretion of the regulatory cytokine IL-10. MBT-primed DCs combined with immune checkpoint inhibitor PD-1 increased mouse survival in a glioma model compared to WT mice. However, mice eventually succumbed to cerebral edema. Histology demonstrated significant treatment effects. CONCLUSION Our results demonstrate that MBT effectively matures DCs ex-vivo. Further research is required to immunophenotype the response to vaccination in glioma models and explore ways to overcome resistance.

Case report: The case report of ofatumumab, a fully human anti-CD20 monoclonal antibody, in the treatment of KLHL11 encephalitis

Case report: The case report of ofatumumab, a fully human anti-CD20 monoclonal antibody, in the treatment of KLHL11 encephalitis

The essential roles of memory B cells in the pathogenesis of systemic lupus erythematosus.

Emerging evidence indicates that memory B cells are dysfunctional in systemic lupus erythematosus (SLE). They are hyporesponsive to signalling through the B cell receptor (BCR) but retain responsiveness to Toll-like receptor (TLR) and type I interferon signalling, as well as to T cell-mediated activation via CD40-CD154. Chronic exposure to immune complexes of ribonucleoprotein (RNP)-specific autoantibodies and TLR-engaging or BCR-engaging cargo is likely to contribute to this partially anergic phenotype. TLR7 or TLR8 signalling and the resulting production of type I interferon, as well as the sustained activation by bystander T cells, fuel a positive feedforward loop in memory B cells that can evade negative selection and permit preferential expansion of anti-RNP autoantibodies. Clinical trials of autologous stem cell transplantation or of B cell-targeted monoclonal antibodies and chimeric antigen receptor (CAR) T cells have correlated replenishment of the memory B cell population with relapse of SLE. Moreover, the BCR hyporesponsiveness of memory B cells might explain the failure of non-depleting B cell-targeting approaches in SLE, including BTK inhibitors and anti-CD22 monoclonal antibodies. Thus, targeting of dysfunctional memory B cells might prove effective in SLE, while also avoiding the adverse events of broad-spectrum targeting of B celland plasma cell subsets that are not directly involved in disease pathogenesis.

CD38 as theranostic target in oncology.

CD38 is a multifunctional transmembrane glycoprotein found in multiple tissues and overexpressed in many cancer cells, notably in hematological malignancies such as leukemia and multiple myeloma (MM). Therefore, targeting CD38 remains an attractive strategy for cancer treatment in hematological malignancies as well as in solid tumors. It plays a critical role in the progression of these diseases through its ADP-ribosyl cyclase and cADPR-hydrolase activities. Its importance has led to the development of various anti-CD38 monoclonal antibodies (mAbs), including daratumumab and isatuximab, approved for MM treatment. These mAbs exert their anti-tumor effects through Fc-dependent immune mechanisms and immunomodulation, enhancing T-cell and NK-cell-mediated responses. However, resistance mechanisms arise during the treatment with daratumumab, creating the necessity for new therapies. This review explains current knowledge about the role of CD38 as a target in oncology and aims to delineate the use of single domain antibodies (sdAbs) as innovative theranostic tools in nuclear medicine. For diagnostic purposes, PET radionuclides like 68Ga, 64Cu, and SPECT radionuclides like 99mTc and 111In, are commonly used. Significant progress has been made in anti-CD38 radioligand therapy (RLT), with anti-CD38 antibodies providing insights into tumor biology and treatment efficacy. In terms of therapy, RLT is a promising approach that offers precise targeting of malignant cells while minimizing exposure to healthy tissue. This involves the use of radionuclides emitting α particles, like 225Ac, 212Pb or 211At, and β--particles like 90Y, 131I, or 177Lu, to exert cytotoxic effects. Derived from Camelidae heavy chain antibodies, sdAbs offer advantages over conventional mAbs such as small size, high stability, specificity, and ability to recognize hidden epitopes. CD38-specific sdAbs, such as sdAb 2F8, characterized by our laboratory, showing excellent tumor targeting and their engineered constructs, such as biparatopic antibodies and chimeric antibodies, represent a new generation of theranostic agents for diagnosis and treatment CD38-expressing malignancies.

Using Soluble CD38 to Overcome Daratumumab Interference in Pretransfusion Compatibility Testing

Background: CD38 is a protein highly expressed on myeloma (MM) cells that has been shown to be an effective target antigen for monoclonal antibody therapies, so treatment with anti-CD38 monoclonal antibodies is a first line therapy for patients with MM. Although CD38 is weaker expressed on erythocytes anti-CD38 binds to CD38 on reagent RBCs and cause panreactivity in vitro and subsequent false positive reactions in indirect antiglobulin tests (IAT), antibody detection (screening) tests, antibody identification panels, and anti-human globulin (AHG) crossmatches. These findings suggest that the soluble CD38 method could improve transfusion safety for patients receiving anti-CD38 therapy, particularly in urgent clinical settings This study aims to evaluate the effectiveness of a new soluble CD38-based method in mitigating Daratumumab interference during pretransfusion compatibility testing." Methods: We evaluated the Grifols sCD38 method in 20 patients and compared it with the DTT method Results: In our experience the sCD38 method reduced testing time from 150 to 50 minutes and demonstrated 100% efficacy, compared to 90% with DTT. The sCD38 effectively mitigated the interference caused by anti-CD38 antibodies in 10 (100% efficacy) of patient samples tested while DTT was successful in only 9/10 (90% efficacy); no interference was observed in patients presenting anti erythrocyte antibodies. Moreover, there was no negative influence on DTT sensitive blood group systems such as KEL upon sCD38 treatment. Conclusions: In our Laboratory, in the year 2023, we processed 129 patients treated with anti-CD38. Therefore the reduction from 150 to 50 minutes in the time needed to perform tests for mitigation of anti-CD38 interference appears to be relevant with a recovery of approximately 210 technical-hours per year. Another highly appreciated operational aspect was the possibility of treating the patient's plasma and perform tests using automatic instruments (Erytra Grifols) available in our laboratory. In the evaluation of this new method, we did not observe failures in the mitigation of anti-CD38 interference. Furthermore, the results obtained in the samples that presented allo or auto antibodies were not affected by the treatment with sCD38. In our experience Grifols sCD38 assay is straightforward and quick to perform ant it is superior to DTT treatment in the mitigation of anti-CD38 antibody interference in MM patients treated with Daratumumab.

Case report:Clinical manifestations and therapeutic options following rhTPO-induced neutralizing antibody production in a child with immune thrombocytopenia.

Recombinant human thrombopoietin (rhTPO) is commonly used to improve low platelet status in immune thrombocytopenia (ITP), as one protein product, even with a very low rate, there is still the possibility to produce neutralizing antibodies of thrombopoietin (TPO). We described a 7-year-old boy with ITP and normal TPO levels who had previously received rhTPO for 2 weeks but showed persistent thrombocytopenia and was misdiagnosed as acquired amegakaryocytic thrombocytopenia (AATP) and ineffectively treated with cyclosporine A (CsA) in combination with avatrombopag (AVA). As suspicious the TPO neutralizing antibody development as re-test of TPO level is 0, the CD20 + deletion antibody drug rituximab (RTX) was prescribed and received efficacy. rhTPO serves as one bio-protein drug and should be cautious with developing neutralizing antibodies if the drug effect is lost. The tests for antibody and/or TPO level should be done for the diagnosis, and the antibody eradication medication as an anti-CD20 antibody, RTX, should be prescribed to delete thes e neutralizing antibodies to recover the TPO level to reattain the response of ITP treatment.

The causal relationship between anti-CD20 antibodies and endometrial cancer: a Mendelian randomization study

PurposeTo determine the effects of anti-B cell surface marker CD20 antibody on the occurrence and progression of endometrial cancer to provide insights into clinical treatment in the future.MethodsWe performed a two-sample Mendelian randomization analysis (MR) to analyze the causal relationship between EC and immune cell markers. The genome-wide association study (GWAS) data of MS4A1 single nucleotide polymorphism encoding gene of CD20 were collected, and a drug target MR analysis was performed to detect the causal relationship between anti-CD20 antibody and the risk of EC. The risk of follicular lymphoma was used as a positive control, and EC was used as the outcome.ResultsEC exerted an effect on 28 immunophenotypes, predominantly on CD20. CD20 in immunoglobulin D+ CD38− B cells, memory B cells, and unsw memory B cells increased after EC onset. In addition, we detected one immunophenotype that exerted a dangerous effect on EC, i.e., CD3/TD CD4+ (mature stage of the T cell group). Simultaneously, CD20 could be used as both a risk factor and a protective factor for EC (P > 0.05). Anti-CD20 antibodies significantly reduced the risk of follicular lymphoma, including two GWAS pooled datasets. In addition, anti-CD20 antibodies exerted a protective effect on EC in two GWAS pooled datasets (P > 0.05).ConclusionOur study confirms the close relationship between CD20 and EC. Anti-CD20 antibodies may exert a protective effect on EC and reduce the risk of EC morbidity, providing a reference for future clinical diagnosis and treatment. However, further clinical verification of our results is warranted.

Asciminib stands out as the superior tyrosine kinase inhibitor to combine with anti-CD20 monoclonal antibodies for the treatment of CD20+ Philadelphia-positive B-cell precursor acute lymphoblastic leukemia in preclinical models.

Philadelphia chromosome-positive B-cell precursor acute lymphoblastic leukemia (Ph+ BCP-ALL) is a high-risk subtype of acute lymphoblastic leukemia characterized by the presence of the BCR::ABL1 fusion gene. Tyrosine kinase inhibitors (TKI) combined with chemotherapy are established as the first-line treatment. Additionally, rituximab, an anti-CD20 monoclonal antibody is administered to adult BCP-ALL patients with ≥20% CD20+ blasts. In this study, we observed a marked prevalence of CD20 expression in patients diagnosed with Ph+ BCP-ALL, indicating a potential widespread clinical application of rituximab in combination with TKI. Consequently, we examined the influence of TKI on the antitumor effectiveness of anti-CD20 monoclonal antibodies by evaluating levels of CD20 on the cell surface and conducting in vitro functional assays. All tested TKI were found to uniformly downregulate CD20 on leukemic cells, diminishing the efficacy of rituximab-mediated complement- dependent cytotoxicity. Interestingly, these TKI displayed varied effects on natural killer (NK) cell-mediated antibody- dependent cytotoxicity and macrophage phagocytic function. While asciminib demonstrated no inhibition of effector cell functions, dasatinib notably suppressed the anti-CD20-monoclonal antibody-mediated NK cell cytotoxicity and macrophage phagocytosis of BCP-ALL cells. Dasatinib and ponatinib also decreased NK cell degranulation in vitro. Importantly, oral administration of dasatinib, but not asciminib, compromised NK cell activity in patients' blood, as determined by an ex vivo degranulation assay. Our results indicate that asciminib might be preferred over other TKI for combination therapy with anti-CD20 monoclonal antibodies.

Venetoclax dose escalation rapidly activates a BAFF/BCL-2 survival axis in chronic lymphocytic leukemia

AbstractVenetoclax, a first-in-class BH3 mimetic drug that targets BCL-2, has improved the outcomes of patients with chronic lymphocytic leukemia (CLL). Early measurements of the depth of the venetoclax treatment response, assessed by minimal residual disease, are strong predictors of long-term clinical outcomes. However, there are limited data on the early changes induced by venetoclax treatment that might inform strategies to improve responses. To address this gap, we conducted longitudinal mass cytometric profiling of blood cells from patients with CLL during the first 5 weeks of venetoclax monotherapy. At baseline, we resolved CLL heterogeneity at the single-cell level to define multiple subpopulations in all patients based on proliferative, metabolic, and cell survival proteins. Venetoclax induced a significant reduction in all CLL subpopulations and caused rapid upregulation of the prosurvival BCL-2, BCL-XL, and mantle cell lymphoma-1 proteins in surviving cells, which had reduced sensitivity to the drug. In mouse models, the venetoclax-induced elevation of survival proteins in B cells and CLL-like cells that persisted was recapitulated, and genetic models demonstrated that extensive apoptosis and access to the B cell cytokine, B cell activating factor (BAFF), were essential. Accordingly, in patients with CLL who were treated with venetoclax or the anti-CD20 antibody obinutuzumab there was marked elevation in BAFF and an increase in prosurvival proteins in leukemic cells that persisted. Overall, these data highlight the rapid adaptation of CLL cells to targeted therapies through homeostatic factors and support cotargeting of cytokine signals to achieve deeper and more durable long-term responses.

Forimtamig, a novel GPRC5D targeting T cell bispecific antibody with 2+1 format for the treatment of multiple myeloma

Despite several approved therapies, multiple myeloma (MM) remains an incurable disease with high unmet medical need. “Off-the-shelf” T-cell bispecific antibodies (TCBs) targeting BCMA and GPRC5D have demonstrated high objective response rates (ORR) in heavily pre-treated MM patients, however, primary resistance, short duration of response and relapse driven by antigen shift frequently occurs. Although GPRC5D represents the most selective target in MM, recent findings indicate antigen loss occurs more frequently than with BCMA. Thus, anti-GPRC5D immunotherapies must hit hard during a short period of time to kill as many myeloma cells as possible. Here, we characterize forimtamig, a novel GPRC5D-targeting TCB with 2+1 format, using preclinical models of MM. Bivalent binding of forimtamig to the N-terminus of GPRC5D confers higher affinity as compared to classical 1+1 TCB formats correlating with formation of more stable immunological synapses and higher potency in tumor cell killing and T cell activation. Using an orthotopic mouse model of MM, forimtamig recruited T effector cells to the bone marrow and induced rapid tumor killing even after the introduction of step-up dosing to mitigate cytokine release. Combination of forimtamig with standard-of-care (SoC) agents including anti-CD38 antibodies, immunomodulatory drugs and proteasome inhibitors improved depth and duration of response. The combination of forimtamig with novel therapeutic agents including BCMA-TCB and Cereblon E3 Ligase Modulatory Drugs (CELMoDs) was potent and prevented occurrence of GPRC5D-negative tumor relapse. Forimtamig is currently being evaluated in Phase 1 clinical trials in relapsed and refractory myeloma (RRMM) patients for monotherapy and in combination treatments. NCT04557150

Preclinical development of SGN-CD47M: Protease-activated antibody technology enables selective tumor targeting of the innate immune checkpoint receptor CD47.

CD47 is a cell surface glycoprotein that is expressed on normal human tissues and has a key role as a marker of self. Tumor cells have coopted CD47 overexpression to evade immune surveillance and thus blockade of CD47 is a highly active area of clinical exploration in oncology. However, clinical development of CD47-targeted agents has been complicated by its robust expression in normal tissues and the toxicities that arise from blocking this inhibitory signal. Further, pro-phagocytic signals are not uniformly expressed in tumors and antibody blockade alone is often not sufficient to drive antitumor activity. The inclusion of an IgG1 antibody backbone into therapeutic design has been shown to serve as an additional pro-phagocytic signal but also exacerbates toxicities in normal tissues. Therefore, a need persists for more selective therapeutic modalities targeting CD47. To address these challenges, we developed SGN-CD47M, a humanized anti-CD47 IgG1 monoclonal antibody linked to novel masking peptides through linkers designed to be cleaved by active proteases enriched in the tumor microenvironment. Masking technology has the potential to increase the amount of drug that reaches the tumor microenvironment, while concomitantly reducing systemic toxicities. We demonstrate that SGN-CD47M is well tolerated in cynomolgus monkeys and displays a 20-fold improvement in tolerability to hematologic toxicities when compared to the unmasked antibody. SGN-CD47M also displays preferential activation in the tumor microenvironment that leads to robust single-agent antitumor activity. For these reasons, SGN-CD47M may have enhanced antitumor activity and improved tolerability relative to existing therapies that target the CD47-SIRPα interaction.

COVID-19 in patients with chronic lymphocytic leukemia treated with venetoclax: what is the role of anti-CD20 antibody?

COVID-19 in patients with chronic lymphocytic leukemia treated with venetoclax: what is the role of anti-CD20 antibody?

Zanubrutinib, obinutuzumab, and venetoclax for first-line treatment of mantle cell lymphoma with a TP53 mutation

AbstractTP53-mutant mantle cell lymphoma (MCL) is associated with poor survival outcomes with standard chemoimmunotherapy. Dual Bruton tyrosine kinase and BCL2-inhibition with or without anti-CD20 monoclonal antibody therapy has shown promising activity in TP53-mutant MCL. We conducted a multicenter, phase 2 study of zanubrutinib, obinutuzumab, and venetoclax (BOVen) in untreated patients with MCL with a TP53 mutation. Patients initially received 160 mg zanubrutinib twice daily and obinutuzumab. Obinutuzumab at a dose of 1000 mg was given on cycle 1 day 1, 8, and 15, and on day 1 of cycles 2 to 8. After 2 cycles, venetoclax was added with weekly dose ramp-up to 400 mg daily. After 24 cycles, if patients were in complete remission with undetectable minimal residual disease (MRD) using an immunosequencing assay, treatment was discontinued. The primary end point was met if ≥11 patients were progression free at 2 years. The study included 25 patients with untreated MCL with a TP53 mutation. The best overall response rate was 96% (24/25) and the complete response rate was 88% (22/25). Frequency of undetectable MRD (uMRD) at a sensitivity level of 1 × 10–5 and uMRD at a sensitivity level of 1 × 10–6 at cycle 13 was 95% (18/19) and 84% (16/19), respectively. With a median follow-up period of 28.2 months, the primary end point was met with a 2-year progression-free survival of 72%, and the 2-year disease-specific and overall survival were 91% and 76%, respectively. Common side effects were generally low grade and included diarrhea (64%), neutropenia (32%), and infusion-related reactions (24%). BOVen was well tolerated and met its primary efficacy end point in TP53-mutant MCL. These data support its use and further evaluation of the BOVen regimen in this high-risk population. This trial was registered at www.ClinicalTrials.gov as #NCT03824483.

Bispecific antibodies as bridging to BCMA CAR-T cell therapy for relapsed/refractory multiple myeloma.

Establishing a strategy for sequencing of T cell redirecting therapies for relapsed/refractory multiple myeloma (RRMM) is a pressing clinical need. We longitudinally tracked the clinical and immunological impact of bispecific T cell engaging antibodies (BsAb) as bridging therapy (BT) to subsequent BCMA-directed CAR-T cell therapies in 52 RRMM patients. BsAbs were a potent and safe option for BT, achieving the highest overall response rate (100%) to BT compared to chemotherapy, anti-CD38 or anti-SLAMF7 antibody based regimens (46%). We observed early CD4+CAR+ and delayed CD8+CAR+ T cell expansion in patients receiving BsAb as BT. In vitro cytotoxicity of CAR-T cells was comparable amongst BT options. Single-cell analyses revealed increased clonality in the CD4+ and CD8+ T cell compartments in patients with previous exposure to BsAbs at leukapheresis and on day 30 after CAR-T infusion. This study demonstrates the feasibility and efficacy of BT with BsAbs for CAR-T cell therapy in RRMM.