Antibody Monotherapy Research Articles

Cryoablation synergizes with anti-PD-1 immunotherapy induces an effective abscopal effect in murine model of cervical cancer

BackgroundImmune checkpoint inhibitors (ICIs), especially anti-PD-1/PD-L1 antibodies, have emerged as promising therapeutic options for cervical cancer. However, the efficacy of anti-PD-1 antibody monotherapy is limited. Cryoablation could elicit an anti-tumor immune response, thereby presenting itself as a potential approach to augment the response of ICIs. The aim of our study was to investigate the systemic immunological effects of cryoablation and the potential synergistic anti-tumor effects of cryoablation and anti-PD-1 antibody in cervical cancer. MethodsWe established U14 murine bilateral subcutaneous cervical cancer model, wherein the primary tumors were treated with cryoablation. Flow cytometry, immunohistochemistry and RNA-seq were used to analyze the immune cell infiltration and immune-associated pathways in the secondary tumor. ResultsOur study revealed that cryoablation reprogrammed the immune landscape, leading to an enhanced infiltration of CD8+ T cell in distant tumors. Cryoablation created a conducive environment for increasing the efficacy of anti-PD-1 immunotherapy. Cryoablation in combination with anti-PD-1 antibody inhibited distant tumors growth and improved mouse survival. Mechanistically, this combination therapy could augment the infiltration of CD8+ T cells, CD4+ T cells, dendritic cells and M1-like tumor-associated macrophages, enhance multiple aspects of antitumor immune response, and reduce immunosuppressive cells such as M2-like tumor-associated macrophages and myeloid-derived suppressor cells in distant tumors. ConclusionsCombination therapy with cryoablation and anti-PD-1 antibody induces an effective abscopal effect in murine model of cervical cancer and may be a novel therapeutic approach for patients with advanced/recurrent cervical cancer.

Comparison of efficacy between anti-PD-1 antibody monotherapy and nivolumab plus ipilimumab therapy as first-line immunotherapy for advanced mucosal melanoma in Japanese patients: A single-center, retrospective cohort study.

Mucosal malignant melanoma (MMM) is a rare subtype of malignant melanoma with a more aggressive biological behavior than cutaneous melanoma (CM). Owing to its rarity, it is necessary to accumulate information on treatments, especially in Asians, in whom MMM occurs more frequently than in Caucasians. In this study, we investigated the efficacy and adverse events (AEs) of nivolumab plus ipilimumab therapy (NIVO+IPI) versus immune checkpoint inhibitor (ICI) monotherapy (PD-1) in Japanese patients with MMM. We reviewed patients with advanced or recurrent MMM who received ICIs as first-line systematic therapy between February 2012 and February 2024 at the Shizuoka Cancer Center. We enrolled a total of 57 patients: 10 (17.5%) were treated with NIVO+IPI, and 47 (82.5%) were treated with PD-1 as first-line systemic therapy. Objective response rates (ORR) did not differ significantly between the NIVO+IPI and PD-1 groups (40.0% vs 27.7%; p = 0.176). There was also no statistically significant difference in progression-free survival (PFS) (median PFS time: 4.3 months vs 9.9 months, log-rank test, p = 0.578) or overall survival (OS) (median OS time: 33.1 months vs. 22.8 months, log-rank test, p = 0.697) between the two groups. However, regarding AEs, grade ≥3 AEs leading to discontinuation of first-line treatment occurred in 80% of patients in the NIVO+IPI group and in 22.6% of patients in the PD-1 group (p = 0.002). No difference was found in the efficacy of NIVO+IPI therapy and anti-PD-1 antibody monotherapy as the first-line treatment for MMM in Japanese patients, but an increase in AEs was observed with combination therapy. This study suggests that patients with MMM may receive less benefit from NIVO+IPI than from PD-1.

Dual neutralization of influenza virus hemagglutinin and neuraminidase by a bispecific antibody leads to improved antiviral activity

Targeting multiple viral proteins is pivotal for sustained suppression of highly mutable viruses. In recent years, broadly neutralizing antibodies that target the influenza virus hemagglutinin and neuraminidase glycoproteins have been developed, and antibody monotherapy has been tested in preclinical and clinical studies to treat or prevent influenza virus infection. However, the impact of dual neutralization of the hemagglutinin and neuraminidase on the course of infection, as well as its therapeutic potential, has not been thoroughly tested. For this purpose, we generated a bispecific antibody that neutralizes both the hemagglutinin and the neuraminidase of influenza viruses. We demonstrated that this bispecific antibody has a dual antiviral activity as it blocks infection and prevents the release of progeny viruses from the infected cells. We show that dual neutralization of the hemagglutinin and the neuraminidase by a bispecific antibody is advantageous over monoclonal antibody combination as it resulted an improved neutralization capacity and augmented the antibody effector functions. Notably, the bispecific antibody showed enhanced antiviral activity in influenza virus-infected mice, reduced mice mortality and limited the virus mutation profile upon antibody administration. Thus, dual neutralization of the hemagglutinin and neuraminidase could be effective in controlling influenza virus infection.

Robust pancreatic tumor suppression by a novel combination treatment with anti-PD-1 immune checkpoint antibody and stroma modifying RNA oligonucleotide STNM01 in mice.

e14630 Background: Tumor stromal remodeling is an obstacle for immune checkpoint blockade therapies. STNM01 is a synthetic RNA oligonucleotide that represses carbohydrate sulfotransferase 15 (CHST15), which is responsible for tumor stromal remodeling. We have previously reported that STNM01 monotherapy by intratumoral injection repressed tumor stromal remodeling while increase tumor-infiltrating T lymphocytes (TILs) in pancreatic tumor-bearing mice. STNM01 was shown to increase TILs in patients with unresectable pancreatic cancer in a Phase I/IIa trial. In the present study, we investigated whether STNM01-mediated TIL enhancement improves anti-tumor effect of anti-PD-1 immune checkpoint antibody by combination treatment in murine models of pancreatic tumor. Methods: In mouse pancreatic cancer KPC and Pan02 subcutaneous syngeneic tumor models, mice were divided into 4 groups for treatment; 1) control, 2) STNM01 monotherapy, 3) anti-PD-1 antibody monotherapy, and 4) combination therapy with STNM01 and anti-PD-1 antibody. Intratumoral injections with 0.9-1.0 mg/mL of STNM01 or control and intraperitoneal administrations of anti-PD-1 antibody or control (5mg/kg) were then performed twice a week for 2 weeks. Mice were sacrificed after 2 week-treatment from baseline, and anti-tumor effects were evaluated by immunohistochemistry for KPC and flowcytometry for Pan02 model, respectively. Results: In the KPC-implanted syngeneic mouse model, combination treatment with intratumoral STNM01 and systemic anti-PD-1 antibody synergistically and robustly suppressed tumor growth as mean % tumor growth inhibition was over 80%. Tumor-infiltrating CD4+ and CD8+ T cells significantly increased in the anti-PD-1 plus STNM01 combination therapy group compared to anti-PD-1 monotherapy group. In the Pan02-implanted syngeneic mouse model, the combination treatment with STNM01 and anti-PD-1 significantly augmented necrosis area of tumor. Flowcytometry analyses showed that tumor-infiltrating CD3+, CD4+ and CD8+ T cells significantly increased in the anti-PD-1 plus STNM01 combination therapy group compared to control group. Although FoxP3+ Treg did not change, the ratio of CD8 to FoxP3 was significantly high only in the anti-PD-1 plus STNM01 combination therapy group. Notably, Ly6C+Ly6G+ granulocytic MDSCs dramatically diminished in the anti-PD-1 plus STNM01 combination therapy group, while anti-PD-1 monotherapy had no impact on tumoral MDSCs. Conclusions: The present work represents the first report of robust synergy between systemic anti-PD-1 antibody and single stroma modifying agent through intratumoral route of administration. Combination usage of STNM01 would provide a novel and clinically feasible therapeutic option to trigger remarkable effect of immune checkpoint inhibitors to this most hard-to-treat solid tumor.

IBI310 (anti-CTLA-4 antibody) monotherapy or in combination with sintilimab in advanced melanoma or urothelial carcinoma

IBI310 is a recombinant fully human IgG1 antibody against cytotoxic T-lymphocyte antigen 4 (CTLA-4). This study was conducted to evaluate IBI310 monotherapy or combination therapy with sintilimab in the patients with advanced melanoma or urothelial carcinoma (UC). Patients in phase Ia received IBI310 at 0.3/1/2/3 mg/kg intravenously (IV) every three weeks (Q3W) following the accelerated titration and 3 + 3 escalation design. Patients in phase Ib received IBI310 (1/2/3 mg/kg IV, Q3W) plus sintilimab (200 mg IV, Q3W) for 4 cycles, followed by sintilimab maintenance therapy. The phase Ib expansion of IBI310 plus sintilimab was performed in patients with advanced melanoma or UC. Overall, 53 patients were enrolled including 10 patients with melanoma in phase Ia, 34 with melanoma and 9 with UC in phase Ib. 94.3% (50/53) patients experienced at least one treatment-related adverse event (TRAE) with most being grade 1-2; 26.4% (14/53) patients experienced grade ≥3 TRAEs. In phase Ia, disease control rate (DCR) was 50.0% (95% CI: 18.7%-81.3%). In phase Ib, objective response rate (ORR) and DCR were 17.6% (95% CI: 6.8%-34.5%) and 44.1% (95% CI: 27.2%-62.1%) respectively for melanoma, and were 22.2% (95% CI: 2.8%-60.0%) and 66.7% (95% CI: 29.9%-92.5%) respectively for UC. IBI310 monotherapy or combination therapy with sintilimab was well-tolerated with favorable antitumor activity across patients with advanced melanoma and UC.

Pharmacological inhibition of HPK1 synergizes with PD-L1 blockade to provoke antitumor immunity against tumors with low antigenicity

Immune checkpoint inhibitors have significantly transformed the landscape of cancer therapy. Nevertheless, while these inhibitors are highly effective for certain patient groups, many do not benefit due to primary or acquired resistance. Specifically, these treatments often lack sufficient therapeutic efficacy against cancers with low antigenicity. Thus, the development of an effective strategy to overcome cancers with low antigenicity is imperative for advancing next-generation cancer immunotherapy. Here, we show that small molecule inhibitor of hematopoietic progenitor kinase 1 (HPK1) combined with programmed cell death ligand 1 (PD-L1) blockade can enhance T-cell response to tumor with low antigenicity. We found that treatment of OT-1 splenocytes with HPK1 inhibitor enhanced the activation of signaling molecules downstream of T-cell receptor provoked by low-affinity-antigen stimulation. Using an in vivo OT-1 T-cell transfer model, we demonstrated that combining the HPK1 inhibitor with the anti-PD-L1 antibody significantly suppressed the growth of tumors expressing low-affinity altered peptide ligand of chicken ovalbumin, while anti-PD-L1 antibody monotherapy was ineffective. Our findings offer crucial insights into the potential for overcoming tumors with low antigenicity by combining conventional immune checkpoint inhibitors with HPK1 inhibitor.

Abstract 1168: Anti-CSF1R antibody monotherapy inhibits minimal residual disease in a novel immunocompetent murine colorectal cancer metastasis model

Abstract Background: The high mortality rate of colorectal cancer (CRC) is primarily due to metastatic disease. Microscopic minimal residual disease (MRD) detected in patients by circulating tumor DNA (ctDNA) may remain radiographically undetectable and persist following therapeutic intervention, resulting in recurrence. Preclinical models are urgently needed to elucidate the mechanisms whereby MRD escapes anti-tumor immune surveillance. We have developed and characterized a preclinical liver MRD model that recapitulates immune response, with the goal to discover novel strategies to improve outcomes for patients with ctDNA+ MRD. Methods: We generated genetically engineered mouse colonic organoids CDX2 CRE; Rosa26 LSL-CAS9-GFP with APC and TP53 mutation and performed intrasplenic injection in syngeneic C57BL/6 mice to recapitulate microsatellite stable CRC metastasis to the liver. Mice were monitored for radiographically detectable disease using MRI. Tumors were resected at various timepoints, with comparison between metastases at various sizes of development (dichotomized as micro- and macro-metastases). We performed multiplex immunofluorescence staining, single cell RNA seq, and spatial transcriptomic analysis to delineate the immune compartments of micro- and macro-metastasis in untreated mice. After identifying colony stimulating factor -1 receptor (CSF1R) as a target, we performed a vehicle controlled anti-CSF1R monotherapy study for 4 weeks. Treatment began at either 7 days before metastasis is radiographically detectable to mimic treatment of MRD, or 21 days post tumor engraftment. Results: Immune exclusion was confirmed through intratumoral CD45+ leukocyte densities, with transition to an immune excluded phenotype occurring above 0.5mm in size (defined as macro-metastases). In our preclinical model, immunosuppressive populations of macrophages (IBA1+CD163+) dominated in the micro-metastases. This observation was confirmed in 13 patients with paired micro- and macro-metastases to the liver (p=0.0065). Strikingly, anti-CSF1R treatment in the murine model eradicated IBA1+CD163+ macrophages (p<0.0001) and induced complete remission of liver micro-metastasis (0/7 mice with residual disease), in contrast to limited efficacy for macro-metastases (5/5 mice with progressed radiographically disease). Additionally, a long-term study confirmed 100% survival (5/5 mice) and no evidence of disease via MRI at 6 months upon anti-CSF1R treatment compared to vehicle (0/5 mice). Conclusions: We established a reproducible preclinical model of MRD with similar immunopathological features of MRD in patients. Our data further identified infiltration of immunosuppressive macrophage populations as an early determinant of MRD progression and indicated CSF1R as a potential new clinical therapeutic target for ctDNA+-defined MRD patients. Citation Format: Alaa M. Mohamed, Kyung Serk Cho, Melinda Soeung, Amanda Anderson, Jumanah Alshenaifi, Ganiraju Manyam, Oscar Villareal, Jennifer Davis, Will Norton, Sisi Gao, Christopher Bristow, Federica Carbone, Stefania Napolitano, Oluwadara Coker, Isha Khanduri, Justin Huang, Dipen M. Maru, Mauro Di Pilato, Ryan Sun, Linghua Wang, David G. Menter, Giannicola Genovese, Giulio Draetta, Natalie Fowlkes, Scott Kopetz. Anti-CSF1R antibody monotherapy inhibits minimal residual disease in a novel immunocompetent murine colorectal cancer metastasis model [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 1168.

Galectin-9 as a regulator of immune interactions in the tumor microenvironment and novel therapeutic target in biliary tract cancer.

555 Background: While results of the TOPAZ-1 trial led to inclusion of anti-PD-1 therapy with standard of care gemcitabine/cisplatin chemotherapy for patients with unresectable biliary tract cancer (BTC), the improvement in overall survival is modest: 12.8 vs 11.5 mos. Identification of novel immunotherapeutic strategies remains a high priority. We discovered Galectin-9 (Gal-9), a carbohydrate-binding protein, is expressed in BTC; it has various immunosuppressive effects, including induction of apoptosis in T cells upon binding to its receptor Tim-3. Defining the role of Gal-9 in the BTC microenvironment will inform how to leverage it as a novel therapeutic target. Methods: Tissue microarrays (TMAs) were constructed from tumors of 66 patients who underwent curative-intent resection of BTC from 2000- 2015 at our institution. These TMAs underwent immunohistochemical staining for CD4, CD8, Gal-9 & Tim-3; the percentage of cells staining positive for each marker was quantified. For each marker, martingale residual plots and bias-adjusted log rank tests were used to identify a cut-off value of “low” versus “high” expression where survival difference was maximal. For in vivo mouse experiments, the syngeneic BTC cell line URCCA4.3 was injected subcutaneously into the flank of C57BL/6 mice, followed by 3 weeks of treatment with anti-Galectin-9 or anti-Tim-3 antibody alone or in combination with anti-PD-1 antibody. Tumor-infiltrating lymphocytes (TILs) were analyzed by flow cytometry. Results: Median overall survival (mOS) was significantly improved in patients with high Gal-9 expression in their tumors, compared to those with low (32.5 mos vs 17.6 mos, p=0.018). However, when patients with high Gal-9 expression were further stratified according to Tim-3, patients with both high Gal-9 & high Tim-3 expression had significantly worse mOS than those with low Tim-3 (22.7 mos vs 113.9 mos, p=0.031), implying that interaction between Gal-9 and Tim-3 wields significant impact on TIL function. There was no difference in OS based on Tim-3 expression alone. When mice bearing BTC tumors were treated with Gal-9 or Tim-3 antibody monotherapy, there was no significant change in tumor growth versus control, but when either was used in combination with PD-1 inhibition, there was a significant reduction in tumor burden at study endpoint. Mice treated with either dual therapy had a significant decrease in CD4+ Treg and increase in CD4+ effector memory TIL populations compared to monotherapy (p<0.05). Conclusions: This study provides unique insight into the role for targeting the Gal-9/Tim-3 pathway in BTC. Our clinical data highlights that co-expression of these markers in BTC tumors is associated with significantly worse OS. Our in vivo pre-clinical studies demonstrate that blockade of either Gal-9 or Tim-3 synergizes with PD-1 targeted antibodies for superior anti-tumor efficacy.

Efficacy and safety of antiviral plus anti-spike monoclonal antibody combination therapy vs. monotherapy for high-risk immunocompromised patients with mild-to-moderate SARS-CoV2 infection during the Omicron era: A prospective cohort study

Antivirals and monoclonal antibodies lower the risk of progression in immunocompromised patients. However, combination therapy with both types of agents has not been studied. This was a single-centre, prospective, cohort study. All immunocompromised patients who received treatment for mild-to-moderate COVID-19 from 1 January 2022 to 30 October 2022 were enrolled. The primary endpoint was COVID-19 progression at 90 days, defined as hospital admission or death due to COVID-19 and/or seronegative persistent COVID-19. A total of 304 patients were included: 43 patients (14.1%) received sotrovimab plus a direct-acting antiviral, and 261 (85.9%) received monotherapy. Primary outcome occurred more frequently after monotherapy (4.6% vs. 0%, P=0.154). Among patients with anti-spike immunoglobulin G (anti-S IgG) titre <750 BAU/mL, COVID-19 progression was more common after monotherapy (23.9% vs. 0%, P=0.001), including more frequent COVID-related admission (15.2% vs. 0%, P=0.014) and seronegative persistent COVID-19 (10.9% vs. 0%, P=0.044). Combination therapy was associated with lower risk of progression (odds ratio [OR] 0.08, 95% confidence interval [95% CI] 0.01-0.64). Anti-S IgG titre <750 BAU/mL and previous anti-CD20 were associated with higher risk of progression (OR 13.70, 95% CI 2.77-67.68; and OR 3.05, 95% CI 1.20-10.94, respectively). In immunocompromised patients, combination therapy with sotrovimab plus an antiviral may be more effective than monotherapy for SARS-CoV2.

Autoantibody profiling of patients with immune checkpoint inhibitor-associated myocarditis: a pilot study.

Immune checkpoint inhibitor (ICI)-associated myocarditis is a rare, but potentially fatal, immune-related adverse event. Hence, identifying biomarkers is critical for selecting and managing patients receiving ICI treatment. Serum autoantibodies (AAbs) in patients with ICI myocarditis may serve as potential biomarkers for predicting, diagnosing, and prognosing ICI myocarditis. We conducted a pilot study using a human proteome microarray with approximately 17,000 unique full-length human proteins to investigate AAbs associated with ICI myocarditis. AAb profiling was performed using sera collected from three patients with ICI myocarditis before the start of ICI treatment and immediately after myocarditis onset. All patients received anti-programmed death-1 antibody monotherapy. At baseline, 116, 296, and 154 autoantigens reacted positively to immunoglobulin G (IgG) in the serum samples from Cases 1, 2, and 3, respectively. Among these proteins, the recombination signal-binding protein for the immunoglobulin kappa J region (RBPJ) was recognized by all three samples, and 32 autoantigens were recognized by any two of the three samples. At the onset of ICI myocarditis, compared to baseline, 48, 114, and 5 autoantigens reacted more strongly with IgG in the serum samples from Cases 1, 2, and 3, respectively. Among these, antibodies against eukaryotic translation initiation factor 4E binding protein 3 (EIF4EBP3) were the most upregulated, with a 38-fold increase. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses highlighted that B-cell receptor signaling, leukocyte transendothelial migration, and thymus development were among the most affected pathways. Enrichment analyses using DisGeNET revealed that proteins reacting to AAbs detected in patients with ICI myocarditis are associated with several diseases, including dilated cardiomyopathy and muscle weakness. This pilot study provides the first integrated analysis of serum AAb profiling in patients with ICI myocarditis and identifies novel candidate markers associated with an increased risk of developing ICI myocarditis and its pathogenesis. However, our results require further independent validation in clinical trials involving a larger number of patients.

Abstract C104: Targeted epigenomic inhibition of MYC enhances responses to immune checkpoint and EGFR inhibitors in preclinical models of NSCLC

Abstract Aberrant expression of the transcription factor MYC is found in most cancers including non-small cell lung cancer (NSCLC) and has critical roles in a wide range of oncogenic processes including immune evasion and EGFR inhibitor resistance. Despite MYC’s therapeutic attractiveness, potent inhibitors of MYC activity have been elusive, due to its intrinsically disordered protein structure and tightly autoregulated expression. We have developed NSCLC-specific programmable epigenomic mRNA therapy, termed a MYC Omega epigenomic controller (NSCLC MYC-OEC) that is designed to target the insulated genomic domain of MYC. We have previously shown that NSCLC MYC-OEC effectively downregulates MYC expression pre-transcriptionally and have demonstrated that NSCLC MYC-OEC inhibits NSCLC patient-derived organoid viability in vitro and abrogates xenograft tumor growth in vivo. To identify combination treatments with NSCLC MYC-OEC, we retrospectively evaluated baseline MYC expression and real-world progression-free survival (PFS) in a cohort of 283 NSCLC patients treated with pembrolizumab, an anti-PD1 monoclonal antibody. This analysis revealed that NSCLC patients with MYC-overexpressing tumors exhibited shorter PFS when treated with pembrolizumab. Moreover, analysis of PD1 or PD-L1 transcript levels in tumors from 13,230 lung adenocarcinoma patients revealed a significant positive correlation between PD1 or PD-L1 and MYC mRNA levels, consistent with a role for MYC in regulation of the immune response. In vivo evaluation of NSCLC MYC-OEC activity and immune checkpoint immunotherapy (ICI) treatment of preclinical Lewis lung carcinoma syngeneic tumor models demonstrated that the combination of NSCLC MYC-OEC with anti-PD-L1 antibody enhanced inhibition of tumor growth and prolonged survival over administration when compared to either NSCLC MYC-OEC or anti-PD-L1 antibody monotherapy. Retrospective analysis of a cohort of 301 NSCLC patients also showed that patients with MYC-overexpressing tumors exhibited significantly shorter PFS when treated with osimertinib, a third generation EGFR inhibitor. To further understand this, we investigated the effects of NSCLC MYC-OEC and osimertinib treatment alone or in combination in EGFR mutant cells, H1975 and PC9. While NSCLC MYC-OEC and osimertinib monotherapy treatments resulted in downregulation of MYC protein expression in both cell lines, combination treatment led to a significantly greater decrease in MYC expression. Furthermore, the combination synergistically reduced H1975 and PC9 cell viability in vitro and led to a significantly greater inhibition of H1975 xenograft growth relative to each single agent in vivo. Together, these data provide preclinical proof-of-concept in NSCLC for development of OEC-mediated pre-transcriptional epigenomic inhibition of MYC expression in combination with immune checkpoint and EGFR inhibitors. Furthermore, these findings suggest that NSCLC MYC-OEC combination with ICI or EGFR-targeted therapy may improve patient outcomes. Citation Format: Defne Yarar, Eugine Lee, Padraich Flahardy, Cameron Vergato, Graeme Hodgson, Thomas McCauley. Targeted epigenomic inhibition of MYC enhances responses to immune checkpoint and EGFR inhibitors in preclinical models of NSCLC [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C104.

EPCORE FL-1: Phase 3 Trial of Subcutaneous Epcoritamab with Rituximab and Lenalidomide (R 2) Vs R 2 Alone in Patients with Relapsed or Refractory Follicular Lymphoma

Background: Follicular lymphoma (FL) is the most common form of indolent non-Hodgkin lymphoma (NHL). Several treatment options are approved by the US Food and Drug Administration for second- or later-line FL therapy, including rituximab + lenalidomide (R 2). However, advanced-stage FL remains incurable and new treatment options for relapsed or refractory (R/R) disease are needed. Epcoritamab, a subcutaneously administered, bispecific antibody that binds CD3 on T lymphocytes and CD20 on B cells, induces potent and selective T-cell-mediated killing of malignant CD20 + B cells (van der Horst et al, Blood Cancer J 2021). In the first-in-human, phase 1/2 EPCORE NHL-1 trial (NCT03625037) in heavily pretreated patients with B-cell NHL (N=68), epcoritamab showed manageable safety and promising single-agent anti-tumor activity (Hutchings et al, Lancet 2021). Among 10 patients with R/R FL, objective response rate (ORR) was 90% (95% CI: 55-100) and complete response (CR) rate was 50%. In the ongoing phase 1b/2 trial evaluating epcoritamab + R 2 for R/R FL (EPCORE NHL-2 arms 2a and 2b; NCT04663347), ORR was 98% among 104 efficacy-evaluable patients, with a complete metabolic response in 87%. Most cytokine release syndrome (CRS) events were low grade (n=111; grade 1-2, 46%; grade 3, 2%) and occurred in cycle 1; all CRS events resolved with routine management. These encouraging data, and the distinct mechanisms of action of epcoritamab and R 2, support ongoing evaluation of this combination for its potential to improve clinical outcomes in patients with R/R FL. The phase 3 EPCORE FL-1 trial was designed to evaluate epcoritamab in combination with R 2 vs R 2 alone in patients with R/R FL with ≥1 prior line of anti-lymphoma therapy. We present an updated protocol, reflecting recent developments and revisions implemented in this study. Study Design and Methods: EPCORE FL-1 (NCT05409066) is a global, randomized, open-label, multicenter phase 3 trial designed to evaluate efficacy and safety of epcoritamab in combination with R 2 vs R 2 alone in patients with R/R FL. Adult patients must have histologically confirmed classic FL (previously grades 1 to 3a FL) stage II, III, or IV with a CD20 + tumor on a representative biopsy based on local pathology report and no evidence of histologic transformation. Patients must have R/R disease after ≥1 prior anti-lymphoma regimen that contained an anti-CD20 monoclonal antibody in combination with chemotherapy; patients receiving only prior anti-CD20 monoclonal antibody monotherapy and/or radiation are not eligible. Other key eligibility criteria include Eastern Cooperative Oncology Group performance status 0 to 2, fluorodeoxyglucose positron emission tomography-avid disease, and ≥1 measurable disease site per Lugano 2014 criteria. Lenalidomide-refractory FL (best response to lenalidomide of stable or progressive disease or progressive disease within 6 months of completion of lenalidomide) is excluded. Approximately 520 patients will be enrolled and randomized 1:1 to receive a full dose of epcoritamab in combination with R 2 or R 2 alone ( Figure); the trial is currently enrolling in 2 arms, Arms A &amp; C. Based on emerging safety and efficacy data, Arm B has been closed to enrollment and the recommended dose of epcoritamab in combination with R 2 is 48 mg. Epcoritamab will be subcutaneously administered using a step-up dosing regimen to full dose in cycle 1 (28 days/cycle). Full dose of epcoritamab will be administered weekly in cycles 2-3 and monthly from cycle 4 onward for up to 12 cycles of treatment. Patients will be serially assessed for disease progression at prespecified intervals. The primary endpoint is progression-free survival assessed by independent review committee (IRC) per Lugano criteria. Key secondary efficacy endpoints include CR rate (by IRC per Lugano criteria), overall survival, and minimal residual disease negativity. Other efficacy endpoints include best overall response, duration of response, duration of complete response, time to progression, event-free survival, time to next anti-lymphoma treatment, and patient-reported outcomes. Safety endpoints include incidence and severity of treatment-emergent adverse events and adverse events of special interest. Exploratory endpoints include assessments of pharmacodynamic and pharmacokinetic data. The study opened for enrollment in 2022 in North America, South America, Europe, Africa, Asia, and Australia.

PD-1 Antibody (Sintilimab) Plus Histone Deacetylase Inhibitor (Chidamide) for the Treatment of Refractory or Relapsed Extranodal Natural Killer/T Cell Lymphoma, Nasal Type (r/r ENKTL): Updates of the Phase Ib/II Scent Study

Background Extranodal natural killer/T-cell lymphoma (ENKTL) is a highly aggressive of non-Hodgkin's lymphoma (NHL) closely related to Epstein-Barr virus (EBV), with a higher incidence in Asia than in Europe and North America. Patients with r/r ENKTL have a poor prognosis after failing asparaginase based regimen, and there is lack of effective treatment. Anti-programmed death 1 (anti-PD-1) antibody monotherapy represented a favorable treatment for the patients with rr-ENKTL. ORIENT-4 trial demonstrated sintilimab(anti-PD-1antibody ) was effective and well tolerated in r/r ENKTL. The efficacy of chidamide monotherapy, an oral subtype-selective histone deacetylase inhibitor (HDACi) was reported on the patients with rr-ENKTL . Moreover, accumulating evidences have shown the synergism between epigenetic modulator and PD-1 antibody. In 2020 ASH meeting, we reported the preliminary results of sintilimab plus chidamide (SC) for treatment of r/r ENKTL orally. This report is an update of this trial with cumulative data of approximately 40 months. Methods This multicenter, single-arm, phase Ib/II clinical trial enrolled eligible patients with histologically confirmed r/r-ENKTL failing from asparaginase-based regimen. This study consisted of a Phase Ib (dose escalation) portion followed by a Phase II expansion portion. In the Phase Ib escalation portion, a standard “3+3” design was utilized to identify the maximum tolerated dose (MTD), dose limited toxicity (DLT) and recommended Phase II dosage (RP2D) of chidamide. Patients received oral escalating doses of chidamide (20, 25, 30 mg) twice a week and 200 mg of sintilimab intravenously every 3 weeks. In the phase II expansion portion, patients received six cycles of SC every 3 weeks. Patients with complete response (CR) or partial response (PR) received SC every 3 weeks for up to 1 year, until disease progression, intolerable toxicity. The primary endpoint was objective response rate (ORR) assessed by investigators per RECIL 2017criteria. Key secondary endpoints included time to response (TTR), duration of response (DOR) and progression-free survival (PFS), overall survival (OS) and safety. Adverse events (AEs) were defined according to National Cancer Institute Common Terminology Criteria for Adverse Events (version 5.0). This trial was registered at ClinicalTrials.gov (NCT 03820596). Results From March 2019 to May 2020, 41 patients were screened, and 37 eligible patients were enrolled. Overall, median age 48 years (range, 20-72), 26 (70.3%) patients with Stage IV, 20 (54.1%) patients with PINK-E score ≥ 3 points, 16 (43.2%) patients received ≥ 2 lines of prior systemic therapy. RP2D of chidamide was 30 mg twice a week. Of 36 response evaluable patients, 21 patients (58.3%) achieved an objective response including 16 (44.4%) patients with CR. The median time to initial response was 6.0 weeks (range, 5.0 to12.4). Cut-off data was July 28, 2023. The median cycles of SC were 6 (range, 2 to 44). Median follow-up time of whole cohort was 38.3 (range, 0.9 to 51.5; Interquartile range [IQR] range 8.5 to 46.3) months, 3-year OS rate was 56% (95% CI: 0.44-0.75, Figure 1 A), median PFS was 23.4 months (Figure 1 B). Twenty-one patients still alive, median follow-up time for this group was 44.9 (IQR 43.2 to 49.3) months. Estimated 4-year PFS rate was 76% (95% CI: 0.51-0.89, Figure 1 C). Median follow-up time of 21 responded(CR+PR) patients was 43.4 (IQR 34.3 to 47.6) months, estimated 4-year DOR was 68% (95% CI: 0.45-0.83, Figure 1 D). Twenty-six (26, 70.3%) patients reported treatment-related AEs (TRAEs). There were no new safety signals were identified after August 2020. The most frequently observed (≥10%) TRAEs were neutropenia (21,56.8%), thrombocytopenia (17, 45.9%), transaminase increased (11, 29.7%), nausea (9, 24.3%). The most frequent Grade (G) ≥3 TRAEs were neutropenia (6, 16.2%) and thrombocytopenia (4, 10.8%). Immune-related AEs were reported in 16 (43.2%) patients including a G4 exfoliative dermatitis, and the most common irAEs were G1 hypothyroidism and rash. TEAEs that led to permanent treatment discontinuation occurred in only one (2.7%) patient. No death was related to the study drug. Conclusion Sintilimab combined with Chidamide showed long-lasting therapeutic effects with manageable toxicity in patients with r/r-ENKTL. Epigenetic modulator can synergize with anti-PD-1 antibody to enhance antitumor activity to r/r-ENKTL.

1473P Efficacy of anti-PD1/PDL1 antibody monotherapy in patients with advanced non-small cell lung cancer with increased hepcidin expression

1473P Efficacy of anti-PD1/PDL1 antibody monotherapy in patients with advanced non-small cell lung cancer with increased hepcidin expression

Activity of tafasitamab in combination with rituximab in subtypes of aggressive lymphoma.

Despite recent advances in the treatment of aggressive lymphomas, a significant fraction of patients still succumbs to their disease. Thus, novel therapies are urgently needed. As the anti-CD20 antibody rituximab and the CD19-targeting antibody tafasitamab share distinct modes of actions, we investigated if dual-targeting of aggressive lymphoma B-cells by combining rituximab and tafasitamab might increase cytotoxic effects. Antibody single and combination efficacy was determined investigating different modes of action including direct cytotoxicity, antibody-dependent cell-mediated cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP) in in vitro and in vivo models of aggressive B-cell lymphoma comprising diffuse large B-cell lymphoma (DLBCL) and Burkitt lymphoma (BL). Three different sensitivity profiles to antibody monotherapy or combination treatment were observed in in vitro models: while 1/11 cell lines was primarily sensitive to tafasitamab and 2/11 to rituximab, the combination resulted in enhanced cell death in 8/11 cell lines in at least one mode of action. Treatment with either antibody or the combination resulted in decreased expression of the oncogenic transcription factor MYC and inhibition of AKT signaling, which mirrored the cell line-specific sensitivities to direct cytotoxicity. At last, the combination resulted in a synergistic survival benefit in a PBMC-humanized Ramos NOD/SCID mouse model. This study demonstrates that the combination of tafasitamab and rituximab improves efficacy compared to single-agent treatments in models of aggressive B-cell lymphoma in vitro and in vivo.

Monocyte subsets associated with the efficacy of anti‑PD‑1 antibody monotherapy.

Immune checkpoint inhibitors (ICIs) are among the most notable advances in cancer immunotherapy; however, reliable biomarkers for the efficacy of ICIs are yet to be reported. Programmed death (PD)-ligand 1 (L1)-expressing CD14+ monocytes are associated with shorter overall survival (OS) time in patients with cancer treated with anti-PD-1 antibodies. The present study focused on the classification of monocytes into three subsets: Classical, intermediate and non-classical. A total of 44 patients with different types of cancer treated with anti-PD-1 monotherapy (pembrolizumab or nivolumab) were enrolled in the present study. The percentage of each monocyte subset was investigated, and the percentage of cells expressing PD-L1 or PD-1 within each of the three subsets was further analyzed. Higher pretreatment classical monocyte percentages were correlated with shorter OS (r=-0.32; P=0.032), whereas higher non-classical monocyte percentages were correlated with a favorable OS (r=0.39; P=0.0083). PD-L1-expressing classical monocytes accounted for a higher percentage of the total monocytes than non-classical monocytes with PD-L1 expression. In patients with non-small cell lung cancer (NSCLC), a higher percentage of PD-L1-expressing classical monocytes was correlated with shorter OS (r=-0.60; P=0.012), which is similar to the observation for the whole patient cohort. Comparatively, higher percentages of non-classical monocytes expressing PD-L1 were significantly associated with better OS, especially in patients with NSCLC (r=0.60; P=0.010). Moreover, a higher percentage of non-classical monocytes contributed to prolonged progression-free survival in patients with NSCLC (r=0.50; P=0.042), with similar results for PD-L1-expressing non-classical monocytes. The results suggested that the percentage of monocyte subsets in patients with cancer before anti-PD-1 monotherapy may predict the treatment efficacy and prognosis. Furthermore, more classical monocytes and fewer non-classical monocytes, especially those expressing PD-L1, are involved in shortening OS time, which may indicate the poor efficiency of anti-PD-1 treatment approaches.

Rebalancing liver-infiltrating CCR3+ and CD206+ monocytes improves diet-induced NAFLD

Melatonin has been reported to improve nonalcoholic fatty liver disease (NAFLD), and exploring the underlying mechanisms will be beneficial for better treatment of NAFLD. Choline-deficient high-fat diet (CDHFD)- and methionine/choline-deficient diet (MCD)-fed mice with melatonin intervention exhibit significantly decreased liver steatosis, lobular inflammation, and focal liver necrosis. Single-cell RNA sequencing reveals that melatonin selectively inhibits pro-inflammatory CCR3+ monocyte-derived macrophages (MoMFs) and upregulates anti-inflammatory CD206+ MoMFs in NAFLD mice. Liver-infiltrating CCR3+CD14+ MoMFs are also significantly increased in patients with NAFLD. Mechanistically, melatonin receptor-independent BTG2-ATF4 signaling plays a role in the regulation of CCR3+ MoMF endoplasmic reticulum stress, survival, and inflammation. In contrast, melatonin upregulates CD206+ MoMF survival and polarization via MT1/2 receptors. Melatonin stimulation also regulates human CCR3+ MoMF and CD206+ MoMF survival and inflammation invitro. Furthermore, CCR3 depletion antibody monotherapy inhibits liver inflammation and improves NAFLD in mice. Thus, therapies targeting CCR3+ MoMFs may have potential benefits in NAFLD treatment.

SI-B001 plus chemotherapy in patients with locally advanced or metastatic EGFR/ALK wild-type non-small cell lung cancer: A phase II, multicenter, open-label study.

9025 Background: SI-B001 is a first-in-class novel EGFR×HER3 bispecific antibody. The objective of this phase II study was to investigate the efficacy and safety of SI-B001 in combination with chemotherapy in pts with locally advanced or metastatic EGFR/ALK wild-type NSCLC. Methods: This phase II study enrolled patients with locally advanced or metastatic EGFR/ALK wild-type NSCLC who had failed first-line anti-PD-1/L1 therapy, with or without platinum-based chemotherapy (PBC). This study consisted of three cohorts: In Cohort A pts received SI-B001 plus PBC as second-line treatment after failure to first-line anti-PD-1/L1 antibody monotherapy; Cohort B pts received SI-B001 plus docetaxel as second-line treatment after failure to first-line anti-PD-1/L1 therapy plus PBC; Cohort C pts received SI-B001 plus docetaxel as third-line or higher treatment after failure to first-line anti-PD-1/L1 therapy and PBC. This study evaluated SI-B001 in three distinct dosing schedules: Schedule 1 (16+9mg/kg once weekly), Schedule 2 (14mg/kg on Days 1 and 8 every 3 weeks), and Schedule 3 (21+12mg/kg once weekly). The primary endpoints of the study were to determine the objective response rate (ORR) in evaluable patients and to identify the optimal dose. The secondary endpoints included assessment of progression-free survival (PFS), disease control rate (DCR), duration of response (DOR), and safety. Results: As of November 11, 2022, 55 pts have been enrolled in the study, including 1 pt in Cohort A, 45 pts in Cohort B, 8 pts in Cohort C, and one pt enrolled based on the investigator's discretion. Of the 55 pts, 48 were evaluable for efficacy; ORR (n/N, [95%CI]) of 31.3% (15/48, [18.7, 46.3]), DCR of 77.1% (37/48, [62.7, 88.0]). In Cohort B, 23 pts were enrolled in schedule 1, 21 pts were enrolled in schedule 2, and 1 pt was enrolled in schedule 3. Of the 45 pts enrolled in Cohort B, 38 were evaluable for efficacy. Among 22 evaluable pts in schedule 1 the ORR was 45.5% (10/22, [24.5, 67.8]) and the DCR was 68.2% (15/22, [45.1, 86.1]). 18 out of the 22 had no actionable genomic alterations (AGA), the ORR was 50.0% (9/18, [26.0, 74.0]), the DCR was 72.2% (13/18, [46.5, 90.3]), and the mPFS has not been reached. The most common grade ≥3 treatment-related adverse events (TRAEs) were myelosuppression (17%), decreased neutrophil count (15%), and decreased white blood cell count (12%). There was no drug-related death. Conclusions: SI-B001 plus docetaxel demonstrated antitumor activity in locally advanced or metastatic NSCLC EGFR/ALK wild-type pts who failed on prior first-line anti-PD-1/L1 antibody plus PBC, especially without AGA. The toxicity of SI-B001 + docetaxel was manageable. These findings support the continued investigation of SI-B001 and docetaxel as a treatment option in NSCLC. Clinical trial information: NCT05020457 .

Response to programmed cell death protein 1 antibody in patients with Epstein-Barr virus-associated biliary tract cancer.

4071 Background: Epstein-Barr virus-associated biliary tract cancer (EBVaBTC) has a distinct genomic landscape and increased infiltration of CD3+ and CD8+ T cells. However, the efficacy of immunotherapy in EBVaBTC remains largely unknown. The aim of this study is to assess the efficacy of programmed cell death protein 1 (PD-1) antibody in EBVaBTC. Methods: Consecutive patients with metastatic biliary tract cancer diagnosed at our institution from January 2017 to December 2021 were identified. In situ hybridization was performed to detect EBV. The objective response to PD-1 antibody was assessed. We also analyzed the immune microenvironment of EBVaBTC by multiplex immunofluorescence staining, and performed the proteomic characterization of EBVaBTC. Results: A total of 131 patients with BTC who received PD-1 antibody were identified, of which 9 (6.9%) had EBVaBTC. All EBVaBTC cases were intrahepatic cholangiocarcinoma. EBVaBTC was not associated with deficient mismatch repair but with lymphoepithelioma-like carcinoma and hepatitis B virus infection. Four (44.4%) patients achieved a partial response, and the remaining five (55.6%) patients had stable disease. The response lasted for at least 12 months in 8 (88.9%) patients with EBVaBTC, including 4 patients received PD-1 antibody monotherapy. Blood EBV-DNA was detectable in all 9 patients (100%) with EBVaBTC. Multiplex immunofluorescence staining revealed more abundant CD3+ and CD8+ T cells infiltration in EBVaBTC than that of mismatch repair deficient BTC. A total of 8,379 proteins were identified by proteomics. Comparison of EBVaBTC and paired normal tissue revealed 547 differentially expressed proteins. Enrichment analysis demonstrated that differentially expressed proteins in the EBVaBTC were associated with EBV infection and T cell activation. We also observed the expression of immune checkpoint other than PD-1, including LAG-3 and TIM-3. Conclusions: Identification of EBVaBTC may represent a subset of patients with promising response to immunotherapy. [Table: see text]

A study of frontline therapy in adults &gt;80 years with chronic lymphocytic leukemia (CLL).

12057 Background: AlthoughCLL primarily affects older adults (median age 71 years), limited data exists about the outcomes of adults who are ≥80 years old because they are under-enrolled on clinical trials. Methods: The Mayo Clinic CLL Database was used to conduct a retrospective cohort study of adults ≥80 years at the time of frontline CLL treatment. Kaplan-Meier analysis was used to plot OS, and cumulative incidence was used to plot TTNT, accounting for competing risk of death. The Mayo Clinic IRB approved the study. Results: Our study included 216 patients with CLL who were age ≥80 years at the time of frontline CLL therapy between 1/1995 and 11/2022 (Table). The median time from CLL diagnosis to initiation of frontline therapy was 3.1 years. The median OS after start of frontline therapy was 3.9 years. The median OS was 3.3 years (95% CI 2.6–4.2) for patients who received alkylating agents (e.g., chlorambucil, n=96), 3.8 years (95% CI 2.8–not reached [NR]) for purine analogues (e.g., fludarabine, n=11), 3.9 years (95% CI 3.2–4.9) for anti-CD20 monoclonal antibody monotherapy (e.g., obinutuzumab, n=64), and not reached (95% CI 3.3-NR) for novel agents (n=43) (P=0.02). The types of novel agents included ibrutinib (n=19), acalabrutinib (n=16), venetoclax (n=7), and orelabrutinib (n=1). There was no difference in OS between 36 patients who received a BTKi compared to the 7 patients who received venetoclax-based therapy. At a median follow-up time of 6.7 years from the first visit, 143 patients died from the following: progressive CLL (n=63), infections (n=12), other cancer (n=11), non-CLL reasons (n=21). Cause of death was unavailable for 36 patients. On multivariable analyses, older age (i.e., any 5-year increase in age) was associated with a 50% increased risk of death (HR 1.5, 95% CI 1.2-1.9, p=0.001), and treatment with non-novel agents was associated with 3.2 times increased risk of death (HR 3.2, 95% CI 1.2-8.9, p=0.02). Of the 216 patients, 76 patients required second-line therapy; the median TTNT was 4.2 years (95% CI 2.9-NE). The most used second-line agents were monoclonal antibodies alone (20/76, 26%) and single-agent alkylators (18/76, 24%). Conclusions: When compared to all other CLL treatments, novel agents such as BTKi and venetoclax-based treatments are associated with significantly improved OS in patients with CLL ≥80 years old when used in the frontline setting. [Table: see text]