Bispecific Antibody Targeting CD3 Research Articles

Talquetamab (Tal) therapy in relapsed/refractory (R/R) multiple myeloma (MM): Assessing weight loss and dysgeusia.

e19514 Background: Tal, a bispecific antibody targeting CD3 and GPRC5D receptors, has shown high response rates in heavily pretreated R/R MM patients. This study aimed to evaluate adverse events (AEs), specifically dysgeusia and weight loss in MM patients treated with tal. Methods: Patients treated at the University of Arkansas for Medical Sciences who received at least one dose of tal were included. Common Terminology Criteria for Adverse Events (CTCAE) was used to grade AEs. The body mass index (BMI)-adjusted weight loss grading system (WLGS) was used to capture weight loss trends over duration of treatment. Weight loss based on BMI was graded based on the BMI-WLGS. Results: 17 patients were included in our analysis. Nine patients (53%) were male. Ten patients (59%) were African American. Median age at diagnosis was 62 (range: 51-75years). Six patients (35%) had Eastern Cooperative Oncology Group (ECOG) performance status ≥2. The median number of prior lines of therapy was seven (range: 3-12). Fourteen patients (82%) received at least one prior autologous hematopoietic stem cell transplant. The median number of tal doses received was 14.8 (range: 2-29). Median time on treatment (ranging from 1.15 to 15.84) was 4.36 months (range: 1.2-15.8 months). Overall response rate (ORR) for was 76%. Cytokine release syndrome occurred in 12 patients (70.6%), with 5 patients (29.4%) in grade 2 or higher CRS. Immune effector cell-associated neurotoxicity syndrome (ICANS) in four patients (23.6%), and 2 patients (11.8%) had grade 2 ICANS. Fourteen patients (82%) developed significant weight loss during treatment with tal. The median weight loss was 11.6 lbs., and median decrease in BMI was 1.85. Median percentage of weight loss was 6.1% from weight prior to tal ranging from 0% to 14.3%. Two patients had grade I, five patients had grade II, six patients had grade III, and one patient had grade IV weight loss per the BMI-WLGS grading system. Fourteen patients (82%) reported dysgeusia during tal treatment. Eight of these patients had grade I dysgeusia, and six patients had grade II dysgeusia. Two patients had persistent dysgeusia even after discontinuation of tal treatment at time of last follow up. Eight patients had weight gain after tal discontinuation (n = 8/14, 57%), with 5 returning to their baseline weight or higher. Six of these patients had dysgeusia during tal, and all six had resolution of dysgeusia after tal discontinuation. Conclusions: In this study, tal resulted in weight loss and dysgeusia in the majority of patients with most cases of dysgeusia resolving after tal discontinuation. Patients, on average, lost 6% of their initial weight during tal treatment. More than two-thirds of patients treated with tal developed BMI-adjusted WLGS grade ≥II. Weight loss persisted in approximately half of the patients after discontinuation of tal. Such AEs need to be discussed with patients and monitored during treatment.

Abstract 6712: LBL-043, a novel LILRB4xCD3 T cell engager, for the treatment of LILRB4 positive leukemia

Abstract Background: Acute myeloid leukemia (AML) is a malignant clonal disorder linked to a broad spectrum of molecular alterations. It is still an incurable cancer, the prognosis is even worse in elderly patients, where overall survival (OS) at 1 year is approximately 10-15%. Now, several CD3 bispecific immunotherapies that harness T cells against AML are at various stages of preclinical and clinical development, but most of them are hampered by the lack of specific targets to distinguish tumor cells from normal hematopoietic stem cells (HSC). Leukocyte immunoglobulin-like receptor B4 (LILRB4) is an immune checkpoint inhibitory receptor, which is highly expressed on FAB M4 and M5 AML cells with a lack of expression on normal HSC and progenitor cells. LILRB4 expression level inversely correlates with OS of patients with M4 and M5 AML. All of these indicate that LILRB4 represents a promising target for developing a T cell redirecting bispecific antibody to treat patients with AML, especially for more aggressive M4 and M5 subtype. Herein a novel bispecific antibody targeting LILRB4 and CD3, LBL-043, is developed to specifically kill LILRB4 positive tumor cells by engaging T cells. Methods: LBL-043 was constructed using our proprietary LeadsBodyTM T cell engager platform, which is a 2:1 format bispecific antibody with two VHH arms targeting LILRB4 with high affinity and one scFv arm targeting CD3 with fine-tuned low affinity. The binding affinity of LBL-043 to LILRB4 and CD3 was determined with Fortebio, while the activity was measured using several cell based assays including reporter gene and TDCC assays. The anti-tumor activity of LBL-043 was investigated in B-NDG/hu-PBMC reconstructed mice implanted with MOLM-13 (human AML-M5a) tumor model. Results: The binding affinity of LBL-043 to LILRB4 and CD3 protein was 0.724 nM and 35.7 nM, respectively. In CD3 reporter gene assays, LBL-043 could activate the NFAT reporter signaling through LILRB4 binding dependent CD3 cross-linking with an EC50 value of 2.459 nM. LBL-043 was shown a potent TDCC activity in different LILRB4 expression level MOLM-13 cells and HL-60 cells with T cell activation and cytokine release. In B-NDG/hu-PBMC reconstructed mice implanted with MOLM-13 tumor cells, LBL-043 was shown significant anti-tumor activity. Simultaneously, LBL-043 can effectively improve the survival rate and maintain relatively stable body weight in the study compared to the vehicle group. Conclusion: LBL-043, a novel bispecific antibody targeting CD3 and LILRB4 with affinity differentiation, induces T cell killing of AML cells by simultaneously binding LILRB4 expressed on tumor cells and CD3 on T cells, redirecting T cells to efficiently killing of AML cells. It is also shown a great anti-tumor efficacy in CDX mouse models. These data support LBL-043 as a novel therapeutic bispecific antibody for the treatment of LILRB4 positive AML and CMML leukemia patients. Citation Format: Yujia Dang, Xiao Huang, Yurong Qin, Xiaoya Liu, Min Chen, Duqing Jiang, Guojin Wu, Mi Ye, Jianming Sun, Baohui Wang, Jing Guan, Tingting Li, Jordan Zhu, Shoupeng Lai, Xiaoqiang Kang, Hong Ling. LBL-043, a novel LILRB4xCD3 T cell engager, for the treatment of LILRB4 positive leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6712.

Abstract 2965: LBL-033, a novel bispecific antibody targeting MUC16 and CD3, for the treatment of tumors over-expressing MUC16

Abstract Background: MUC16 is a large glycoprotein overexpressed on cell membrane of solid tumors, especially in almost 80% of ovarian cancer. The extracellular part of MUC16 could be cleaved as CA125, which is well known as a diagnosis biomarker for ovarian cancer. Despite recent advances in therapies such as PARP inhibitors, advanced ovarian cancer remains a disease of high unmet need. Herein a novel bispecific antibody targeting MUC16 and CD3, LBL-033, is developed to specifically kill MUC16 positive tumor cells by engaging T cells. Methods: LBL-033 was constructed using our unique T cell engager platform, which is a 2:1 format bispecific antibody with two arms targeting MUC16 membrane-proximal domain with high affinity and one arm targeting CD3 with fine-tuned affinity. The binding affinity of LBL-033 to MUC16 and CD3 was determined with Fortebio, while the activity was measured using several cell based assays including reporter gene and TDCC assays. The anti-tumor activity of LBL-033 was investigated in C57BL/6-huCD3e mice implanted with MC38-huMUC16 cells. GLP-compliant repeat-dose toxicologic study was evaluated in cynomolgus monkeys. Results: The binding affinity of LBL-033 to MUC16 and CD3 protein was 2.67 nM and 29.6 nM, respectively. The epitope that anti-MUC16 binds was identified at the C-terminal of MUC16 extracellular domain; and the activity was not affected in the presence of soluble CA-125. In CD3 reporter gene assay, LBL-033 could activate the NFAT reporter element through MUC16 antigen-dependent CD3 cross-linking with an EC50 value of 1.068 nM. LBL-033 was shown a potent TDCC activity in OVCAR3 cells with T cell activation. In C57BL/6-huCD3e transgenic mice implanted with MC38-huMUC16 tumor cells, LBL-033 was shown a dose dependent anti-tumor activity. In addition, LBL-033 had a significant synergistic effect, when combined with anti-PD-1. LBL-033 was shown favorable pharmacokinetic properties with a good safety profile in cynomolgus monkeys. Conclusion: LBL-033, a novel bispecific antibody targeting CD3 and MUC16 with a unique epitope, which is located at the MUC16 membrane-proximal domain, with affinity differentiation between anti-MUC16 and anti-CD3. It is shown a great anti-tumor efficacy in animal models, with a good safety profile in monkeys. These data support LBL-033 as a novel therapeutic bispecific antibody for ovarian cancer and other MUC16 positive tumors. A dose escalation study in humans will begin in Q1 2023. Citation Format: Jianming Sun, Xiao Huang, Yurong Qin, XingXing Fang, Min Chen, Huan Lin, Jing Guan, Jing Huang, Tongjun Liu, Baohui Wang, Guojin Wu, Shoupeng Lai, Xiaoqiang Kang, Hong Ling. LBL-033, a novel bispecific antibody targeting MUC16 and CD3, for the treatment of tumors over-expressing MUC16 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2965.

Elrexfio™ (elranatamab-bcmm): The game-changer in treatment of multiple myeloma.

Multiple myeloma is the second most common plasma cell malignancy, characterized by uncontrolled proliferation of plasma cells within the bone marrow. ELREXFIO™ (elranatamab-bcmm) is a recently FDA-approved drug for relapsed and refractory multiple myeloma. The progression of multiple myeloma involves interactions with various bone marrow cell types, and targeting this microenvironment has shown promising results in inhibiting its growth and osteolysis. ELREXFIO, a bispecific antibody targeting CD3 and BCMA, activates cytotoxic T-lymphocyte responses against BCMA-expressing myeloma cells. Clinical trials, such as MagnetisMM-3, demonstrated significant response rates and long-term tolerability. Its approval offers hope to multiple myeloma patients, especially those with relapsed or refractory cases, as innovative therapies like ELREXFIO continue to improve outcomes in this challenging malignancy.

Subcutaneous epcoritamab + R-DHAX/C in patients (pts) with relapsed or refractory (R/R) diffuse large B-cell lymphoma (DLBCL) eligible for autologous stem cell transplant (ASCT): Preliminary phase 1/2 results.

7528 Background: Current standard of care for pts with R/R DLBCL eligible for ASCT includes salvage immunochemotherapy, such as rituximab, dexamethasone, cytarabine, and oxaliplatin or carboplatin (R-DHAX/C), followed by consolidation with high-dose therapy (HDT) and ASCT. However, salvage therapy fails in many pts, and novel treatment (Tx) options are needed to improve response and long-term outcomes. Epcoritamab, a bispecific antibody targeting CD3 on T cells and CD20 on B cells, had a manageable safety profile and meaningful single-agent antitumor activity in pts with heavily pretreated B-cell non-Hodgkin lymphoma (NHL) in the dose-escalation part of the EPCORE NHL-1 trial. Here we present initial results from arm 4 (epcoritamab + R-DHAX/C) of the EPCORE NHL-2 phase 1/2 trial (NCT04663347). Methods: Adults with R/R CD20+ DLBCL who were eligible for HDT-ASCT were enrolled. Pts received standard R-DHAX/C with subcutaneous epcoritamab (QW, 21-d cycle [C] 1–3). If HDT-ASCT was postponed, pts could continue epcoritamab monotherapy (28-d C: QW, C4; Q2W, C5–9; Q4W, C≥10) until disease progression or unacceptable toxicity. Step-up epcoritamab dosing and corticosteroids were required to mitigate CRS in C1. Response was determined by PET-CT per Lugano criteria. Results: As of Jan 26, 2022, 27 pts (median age, 59 y; range, 30–75) had received epcoritamab + R-DHAX/C. Of these, 74% had received 1 prior line of therapy, the remainder (26%) 2–3 prior therapies; 3 pts had prior CAR T. The majority of pts (70%) had primary refractory disease. The most common Tx-emergent adverse events (any grade [G]) were thrombocytopenia (67%), neutropenia (48%; febrile neutropenia, 19% in all pts), infections (37%), nausea (37%), and anemia (33%). Adverse events of special interest were CRS in 8 pts (30%; all G1/2) and ICANS in 1 pt (G2; discontinued epcoritamab, pt with prior CAR T). No clinical tumor lysis syndrome was observed. CRS events occurred early in Tx; median time to resolution was 2 d. Of the 23 evaluable pts, 11 pts underwent ASCT; among these, overall response rate (ORR) was 100% prior to ASCT (82% [9/11] complete metabolic response [CMR]; 18% [2/11] partial metabolic response [PMR]). In 12 pts, HDT-ASCT was postponed/canceled and epcoritamab monotherapy continued; of these, 5 (42%, including 2 with prior CAR T) had CMR and 3 (25%) had PMR. The CMR and PMR rates for the entire evaluable population were 61% (14/23) and 22% (5/23), respectively. Conclusions: Subcutaneous epcoritamab in combination with R-DHAX/C in pts with R/R DLBCL had a manageable safety profile. CRS events were of low grade and resolved with standard management. ORR and CMR rate were high. At the time of data cutoff, 70% of pts had either received ASCT or continued epcoritamab Tx in CMR. Clinical trial information: NCT04663347.

A Novel Bispecific Antibody Targeting CD3 and Lewis Y with Potent Therapeutic Efficacy against Gastric Cancer.

Lewis Y antigen, a glycan highly expressed on most epithelial cancers, was targeted for cancer treatment but lacked satisfactory results in some intractable and refractory cancers. Thus, it is highly desirable to develop an effective therapy against these cancers, hopefully based on this target. In this work, we constructed a novel T cell-engaging bispecific antibody targeting Lewis Y and CD3 (m3s193 BsAb) with the IgG-[L]-scfv format. In vitro activity of m3s193 BsAb was evaluated by affinity assay to target cells, cytotoxicity assay, cytokines releasing assay, and T cells proliferation and recruiting assays. Anti-tumor activity against gastric cancer was evaluated in vivo by subcutaneous huPBMCs/tumor cells co-grafting model and huPBMCs intravenous injecting model. In vitro, m3s193 BsAb appeared to have a high binding affinity to Lewis Y positive cells and Jurkat cells. The BsAb showed stronger activity than its parent mAb in T cell recruiting, activation, proliferation, cytokine release, and cytotoxicity. In vivo, m3s193 BsAb not only demonstrated higher therapeutic efficacy in the huPBMCs/tumor co-grafting gastric carcinoma model than the parent mAb but also eliminated tumors in the model of intravenous injection with huPBMCs. Strong anti-tumor activity of m3s193 BsAb revealed that Lewis Y could be targeted in T cell-engaging BsAb for gastric cancer therapy.

A novel bispecific antibody targeting CD3 and prolactin receptor (PRLR) against PRLR-expression breast cancer

BackgroundProlactin receptor (PRLR) is highly expressed in a subset of human breast cancer and prostate cancer, which makes it a potential target for cancer treatment. In clinical trials, the blockade of PRLR was shown to be safe but with poor efficacy. It is therefore urgent to develop new therapies against PRLR target. Bispecific antibodies (BsAbs) could guide immune cells toward tumor cells, and produced remarkable effects in some cancers.MethodsIn this study, a bispecific antibody targeting both tumor antigen PRLR and T cell surface CD3 antigen (PRLR-DbsAb) was constructed by split intein mediated protein transsplicing (BAPTS) system for the first time. Its binding activity was determined by Biacore and Flow cytometry, and target-dependent T cell mediated cytotoxicity was detected using LDH release assay. ELISA was utilized to study the secretion of cytokines by immune cells. Subcutaneous tumor mouse models were used to analyze the in vivo anti-tumor effects of PRLR-DbsAb.ResultsPRLR-DbsAb in vitro could recruit and activate T cells to promote the release of Th1 cytokines IFN- γ and TNF- α, which could kill PRLR expressed breast cancer cells. In xenograft models with breast cancer cell line T47D, NOD/SCID mice intraperitoneally injected with PRLR-DbsAb exhibited significant inhibition of tumor growth and a longer survival compared to mice treated with PRLR monoclonal antibody (PRLR mAb).ConclusionsBoth in vitro and in vivo experiments showed PRLR-DbsAb had a potential therapy of cancer treatment potential therapy for cancer. Immunotherapy may be a promising treatment against the tumor target of PRLR.

5O - GBR1302-BEAT® bispecific antibody targeting CD3 and HER2 demonstrates a higher anti-tumor potential than current HER2-targeting therapies

Aim/Background: Current HER2-targeting therapies (such as Herceptin or TDM-1) have demonstrated efficacy only in cancers significantly overexpressing HER2 (cancers characterized as HER2 3+ according to the IHC HercepTest®) and are also limited by several possible resistance mechanisms. Bridging T lymphocytes to HER2 tumor cells has the potential to trigger a more efficient elimination of tumor cells. Using the Glenmark BEAT® platform, we have produced a bispecific antibody, GBR 1302, targeting human CD3ε and HER2 and designed to effectively recruit cytotoxic T lymphocytes against HER2 positive cancer cells. These studies aimed at comparing the potency of GBR 1302 and the current HER-2 targeting therapies. Methods: Short term (48 hours) in vitro killing assays, against different breast or gastric tumor cell lines characterized as HER2 3+ or 2+ by IHC HercepTest and using resting human PBMCs from healthy donors as effector cells. Metabolic or colony forming readouts were performed to quantify tumor cell death. In vivo tumor xenograft models, either subcutaneous or disseminated (intravenous injection of the cells). The tumor cells were grafted with human PBMCs to bring effector cells. The treatments were started the day of the tumor+PBMC graft. Results: Killing experiments comparing the potency of GBR 1302 to current HER2-targeting therapies such as trastuzumab or T-DM1 highlighted a more efficient, rapid and complete cytotoxic potential for GBR 1302 against a variety of tumor cells. In particular, killing assays on breast or gastric tumor cell lines characterized as HER2 3+ or 2+ by IHC HercepTest, followed by a clonogenic readout or an absolute count of viable target cells, revealed a significantly more complete killing by GBR 1302 as compared to T-DM1. Tumor xenograft models confirmed these data, by showing that T-DM1 could only slow subcutaneous tumor growth, or delay the time of sacrifice of mice in a metastatic model, while GBR 1302 was able to abrogate almost completely tumor development. Conclusions: These observations highlight that GBR 1302, consistent with its mechanism of action, is able to trigger a rapid and very potent mobilization of T lymphocyte cytotoxic functions against cancer cells. These features warrant for GBR 1302 a potential to elicit in patients a more complete response in a shorter period compared to current HER2 targeting treatments which are essentially cytostatic drugs, thereby limiting the probability of the emergence and Darwinian selection of resistant cells. Legal entity responsible for the study: Glenmark Pharmaceuticals S.A Funding: Glenmark Pharmaceuticals S.A Disclosure: J. Back: Employee of Glenmark Pharmaceuticals S.A

Monitoring and functional characterization of the lymphocytic compartment in pancreatic ductal adenocarcinoma patients

Background/ObjectivesPancreatic ductal adenocarcinoma (PDAC) still has a poor prognosis and current treatments including immunotherapy often fail. This might be due to the pronounced immunosuppressive milieu impairing infiltration and function of immune effector cells. This study aimed at a comprehensive analysis of immune cells in PDAC patients by determining absolute and relative peripheral blood cell numbers of immune cell subsets along with their functional capacity. MethodsWhole blood cells or isolated peripheral blood mononuclear cells were characterized by flow cytometry. PDAC tissues were analyzed by immunohistochemistry. Anti-tumor activity of immune effector cells was determined by RTCA system. ResultsOur data demonstrate that relative CD4+ memory- and regulatory T cell numbers were enhanced, whereas determination of absolute cell numbers revealed generally lower immune cell numbers in PDAC patients compared to healthy controls. γδ T cells accumulated at higher numbers compared to αβ T cells in the malignant ductal epithelium of PDAC tissues indicating that γδ T cells infiltrate into the tumor. Cytotoxicity against tumor cells of even small numbers of T- and NK cells could be induced by a bispecific antibody targeting CD3+ T cells to human epidermal growth factor receptor (HER)2 expressing PDAC cells or Trastuzumab. Importantly, a critical number of γδ T cells was required for significant tumor cell killing by a bispecific antibody engaging the γδ T cell receptor on γδ T cells and HER2 on tumor cells. ConclusionMonitoring immune cells along with the determination of their functional capacity provides a comprehensive assessment as a prerequisite for a personalized immunotherapeutic PDAC treatment.