Efficacy Of Antibody-drug Conjugates Research Articles

Site-Specific Quadruple-Functionalised Antibodies.

Antibody-drug conjugates (ADCs) are a growing class of chemotherapeutic agents that have yielded striking clinical successes. However, the efficacy of ADCs often suffers from issues associated with tumor heterogeneity and resistance. To overcome these problems, a new generation of ADCs comprising a single monoclonal antibody with multiple different payloads attached, termed multi-payload ADCs, have been developed. Here we deploy multiple orthogonal site-specific protein modification strategies to generate highly homogeneous multi-functionalised antibody conjugates comprising up to four different functionalities installed at four unique sites on the antibody. This work, which includes the use of a site-specific cyclopropenone (CPO)-based reagent, represents the first example of a homogeneous multi-payload ADC with a payload count greater than two, and thereby facilitates the development of the next generation of ADCs.

The Journey of Antibody-Drug Conjugates: Lessons Learned from 40 Years of Development.

Antibody-drug conjugates (ADC) represent one of the most rapidly expanding treatment modalities in oncology, with 11 ADCs approved by the FDA and more than 210 currently being tested in clinical trials. Spanning over 40 years, ADC clinical development has enhanced our understanding of the multifaceted mechanisms of action for this class of therapeutics. In this article, we discuss key insights into the toxicity, efficacy, stability, distribution, and fate of ADCs. Furthermore, we highlight ongoing challenges related to their clinical optimization, the development of rational sequencing strategies, and the identification of predictive biomarkers. Significance: The development and utilization of ADCs have allowed for relevant improvements in the prognosis of multiple cancer types. Concomitantly, the rise of ADCs in oncology has produced several challenges, including the prediction of their activity, their utilization in sequence, and minimization of their side effects, that still too often resemble those of the cytotoxic molecule that they carry. In this review, we retrace 40 years of development in the field of ADCs and delve deep into the mechanisms of action of these complex therapeutics and reasons behind the many achievements and failures observed in the field to date.

Antibody Modification via Lipoic Acid Ligase A-Mediated Site-Specific Labeling.

Enzymatic modification, particularly utilizing lipoic acid ligase (LplA), has emerged as a transformative approach in biopharmaceuticals, enabling precise and site-specific protein modifications. This review delves into the innovative applications of LplA in antibody modifications, including the creation of antibody-drug conjugates (ADCs) and the advancement of tag-free conjugation techniques. LplA's ability to facilitate the incorporation of bioorthogonal groups and its adaptability to various substrates underscores its versatility. Key developments include the successful generation of dual-labeled antibodies and the application of LplA in modifying antibody fragments. Additionally, the review explores the potential for LplA to enhance the therapeutic efficacy of ADCs through improved drug-to-antibody ratios and site-specific payload attachment. The implications of these advancements are significant, suggesting that LplA-mediated modifications could lead to more effective and targeted antibody-based therapies. This review aims to provide a comprehensive overview of LplA's role in expanding the possibilities of enzymatic conjugation, setting the stage for future research and clinical applications.

201P Efficacy of antibody drug conjugate (ADC) by mRNA expression of targeted genes in advanced solid tumors: SCRUM-Japan MONSTAR-SCREEN-2

201P Efficacy of antibody drug conjugate (ADC) by mRNA expression of targeted genes in advanced solid tumors: SCRUM-Japan MONSTAR-SCREEN-2

655P Toxicity and efficacy of antibody drug conjugates (ADC) in advanced solid tumors: A pooled analysis of Sarah Cannon UK

655P Toxicity and efficacy of antibody drug conjugates (ADC) in advanced solid tumors: A pooled analysis of Sarah Cannon UK

Antibody-drug conjugates in gastric cancer: from molecular landscape to clinical strategies.

Antibody-drug conjugates (ADCs) represent a crucial component of targeted therapies in gastric cancer, potentially altering traditional treatment paradigms. Many ADCs have entered rigorous clinical trials based on biological theories and preclinical experiments. Modality trials have also been conducted in combination with monoclonal antibody therapies, chemotherapies, immunotherapies, and other treatments to enhance the efficacy of drug coordination effects. However, ADCs exhibit limitations in treating gastric cancer, including resistance triggered by their structure or other factors. Ongoing intensive researches and preclinical experiments are yielding improvements, while enhancements in drug development processes and concomitant diagnostics during the therapeutic period actively boost ADC efficacy. The optimal treatment strategy for gastric cancer patients is continually evolving. This review summarizes the clinical progress of ADCs in treating gastric cancer, analyzes the mechanisms of ADC combination therapies, discusses resistance patterns, and offers a promising outlook for future applications in ADC drug development and companion diagnostics.

Tuning Immune-Cold Tumor by Suppressing USP10/B7-H4 Proteolytic Axis Reinvigorates Therapeutic Efficacy of ADCs.

Tuning immune-cold tumor hot has largely attracted attention to improve cancer treatment, including immunotherapy and antibody-drug conjugates (ADCs). Utilizing multiomic analyses and experimental validation, this work identifies a pivotal role for the USP10/B7-H4 proteolytic axis in mediating the interplay between tumor immune responses and ADC efficacy, particularly for sacituzumab govitecan (SG) in treating triple negative breast cancers (TNBCs). Mechanistically, the inhibition of autocrine motility factor receptor (AMFR)-mediated ubiquitylation of B7-H4 by the deubiquitinase USP10 leads to the stabilization of B7-H4, which suppresses tumor immune activity and reduces SG treatment effectiveness. Pharmacological inhibition of USP10 promotes the degradation of B7-H4, enhancing tumor immunogenicity and consequently improving the tumor-killing efficacy of SG. In preclinical TNBC models, suppression of USP10/B7-H4 proteolytic axis is effective in increasing SG killing efficacy and reducing tumor growth, especially for the tumors with the USP10high/B7-H7high signature. Collectively, these findings uncover a novel strategy for targeting the immunosuppressive molecule B7-H4 for cancer therapy.

Exploring the Role of Target Expression in Treatment Efficacy of Antibody-Drug Conjugates (ADCs) in Solid Cancers: A Comprehensive Review.

Antibody-drug conjugates (ADCs) offer a promising path for cancer therapy, leveraging the specificity of monoclonal antibodies and the cytotoxicity of linked drugs. The success of ADCs hinges on precise targeting of cancer cells based on protein expression levels. This review explores the relationship between target protein expression and ADC efficacy in solid tumours, focusing on results of clinical trials conducted between January 2019 and May 2023. We hereby highlight approved ADCs, revealing their effectiveness even in low-expressing target populations. Assessing target expression poses challenges, owing to variations in scoring systems and biopsy types. Emerging methods, like digital image analysis, aim to standardize assessment. The complexity of ADC pharmacokinetics, tumour dynamics, and off-target effects emphasises the need for a balanced approach. This review underscores the importance of understanding target protein dynamics and promoting standardized evaluation methods in shaping the future of ADC-based cancer therapies.

The Evolution of Antibody-Drug Conjugates: Toward Accurate DAR and Multi-specificity.

Antibody-drug conjugates (ADCs) consist of antibodies, linkers and payloads. They offer targeted delivery of potent cytotoxic drugs to tumor cells, minimizing off-target effects. However, the therapeutic efficacy of ADCs is compromised by heterogeneity in the drug-to-antibody ratio (DAR), which impacts both cytotoxicity and pharmacokinetics (PK). Additionally, the emergence of drug resistance poses significant challenges to the clinical advancement of ADCs. To overcome these limitations, a variety of strategies have been developed, including the design of multi-specific drugs with accurate DAR. This review critically summarizes the current challenges faced by ADCs, categorizing key issues and evaluating various innovative solutions. We provide an in-depth analysis of the latest methodologies for achieving homogeneous DAR and explore design strategies for multi-specific drugs aimed at combating drug resistance. Our discussion offers a current perspective on the advancements made in refining ADC technologies, with an emphasis on enhancing therapeutic outcomes.

Update of antibody-drug conjugates for hematological malignancies.

Antibody-drug conjugates (ADCs), consisting of monoclonal antibodies (mAbs) covalently linked to cytotoxic drugs via chemical linkers, are a kind of promising tumor immunotherapy. ADCs also face a number of challenges, including unavoidable adverse effects, drug resistance, tumor targeting and payload release. To address these issues, in addition to optimizing the individual components of ADCs, such as new payloads, linkage sites and new targets, and using bispecific antibodies to increase precision, attention should be paid to optimizing the dosage of ADCs. There are currently 7 ADCs approved for marketing by the Food and Drug Administration (FDA) for hematological malignancies, and dozens of other ADCs are either in clinical trials or in the process of applying for marketing. In recent clinical studies targeting ADCs in hematologic malignancies, in addition to validating effectiveness in different indications, researchers have attempted to combine ADCs with other chemotherapeutic agents in anticipation of increased therapeutic efficacy. Furthermore, the availability of bispecific antibodies may increase the safety and efficacy of ADCs. This review summarized the progress of research on ADCs in hematological malignancies, the challenges being faced, and possible future directions to improve the efficacy of ADCs, which can provide novel insight into the future exploration of ADCs in the treatment of hematological malignancies.

CD20 expression regulates CD37 levels in B-cell lymphoma – implications for immunotherapies

ABSTRACT Rituximab (RTX) plus chemotherapy (R-CHOP) applied as a first-line therapy for lymphoma leads to a relapse in approximately 40% of the patients. Therefore, novel approaches to treat aggressive lymphomas are being intensively investigated. Several RTX-resistant (RR) cell lines have been established as surrogate models to study resistance to R-CHOP. Our study reveals that RR cells are characterized by a major downregulation of CD37, a molecule currently explored as a target for immunotherapy. Using CD20 knockout (KO) cell lines, we demonstrate that CD20 and CD37 form a complex, and hypothesize that the presence of CD20 stabilizes CD37 in the cell membrane. Consequently, we observe a diminished cytotoxicity of anti-CD37 monoclonal antibody (mAb) in complement-dependent cytotoxicity in both RR and CD20 KO cells that can be partially restored upon lysosome inhibition. On the other hand, the internalization rate of anti-CD37 mAb in CD20 KO cells is increased when compared to controls, suggesting unhampered efficacy of antibody drug conjugates (ADCs). Importantly, even a major downregulation in CD37 levels does not hamper the efficacy of CD37-directed chimeric antigen receptor (CAR) T cells. In summary, we present here a novel mechanism of CD37 regulation with further implications for the use of anti-CD37 immunotherapies.

Mechanisms of action and resistance to anti-HER2 antibody-drug conjugates in breast cancer.

Human epidermal growth factor 2 (HER2)-positive breast cancer (BC) represents nearly 20% of all breast tumors. Historically, these patients had a high rate of relapse and dismal prognosis. The advent of HER2-targeting monoclonal antibodies such as trastuzumab followed by pertuzumab had improved the prognosis of HER2-positive metastatic BC. More recently, antibody-drug conjugates (ADCs) are now reshaping the treatment paradigm of solid tumors, especially breast cancer. Tratsuzumab emtansine (T-DM1) was one of the first ADC developed in oncology and was approved for the management of HER2-positive metastatic BC. In a head-to-head comparison, trastuzumab deruxtecan (T-DXd) defeated T-DM1 as a second-line treatment. The efficacy of ADCs is counterbalanced by the appearance of acquired resistance to these agents. In this paper, we summarize the mechanisms of action and resistance of T-DM1 and T-DXd, as well as their clinical efficacy. Additionally, we also discuss potential strategies for addressing resistance to ADC.

Comparison of efficacy of antibody drug conjugate (ADCs) between younger and older patients: A meta-analysis of phase 3 studies.

e15002 Background: Antibody-Drug-Conjugates (ADCs) are one of the new cornerstone of cancer treatments. New approvals are coming every year in various tumor types and settings. However, older adults remain underrepresented in clinical trials and consequently, few data is available for this population. Therefore, we performed a meta-analysis to compare the efficacy of ADCs between younger and older patients. Methods: PubMed and the ASCO or ESMO databases were searched up to December 2023. We included randomized controlled trials (RCTs) of ADCs (datopotamab deruxtecan, Enfortumab vedotin, mirvetuximab soravtansine, sacituzumab govitecan and trastuzumab deruxtecan) reporting subgroup comparison of overall survival (OS) and/or progression-free survival (PFS) based on age cutoffs. The summary hazard ratio (HR) and 95% confidence interval (CI) were calculated. Results: A total of 4654 patients from nine RCTs (ASCENT; DESTINY-Breast02, -Breast04, -Gastric01; EV-301, EV-302/KEYNOTE-A39; MIRASOL; TROPiCS-02 and TROPION-Lung01) were included. When patients are dichotomized into younger (N=2796) and older (N=1858) groups with an age cut-off of 65 years, ADCs improved OS in both younger (HR, 0.64; 95% CI, 0.52-0.80) and older (HR, 0.56; 95% CI, 0.44-0.71) groups. An improvement in PFS was observed in younger (HR, 0.55; 95% CI, 0.46-0.66) and older (HR, 0.52; 95% CI, 0.41-0.67) patients. Subgroup analyses according to ADCs and tumor type showed a consistent survival benefit in both younger and older groups. Conclusions: A benefit in OS with ADCs was significant in both younger and older patients with a cut-off age of 65 years. Prospective real life cohort study would be of interest to confirm those results with a description of geriatric parameters to better define the population.

Sequential combination of sacituzumab govitecan and talazoparib in metastatic triple negative breast cancer (mTNBC): Results from a phase II study.

1102 Background: The antibody-drug conjugate (ADC) sacituzumab govitecan (SG) has demonstrated improvement in overall survival for patients with metastatic triple negative breast cancer (mTNBC). Despite great interest in enhancing efficacy of ADCs using combination therapy, there are no approved regimens. Preclinical data suggest that SG synergizes with Poly ADP-ribose polymerase inhibitors (PARPi) to induce DNA damage and cell death. Though the phase 1b study demonstrated intolerable myelosuppression with simultaneous dosing, tolerability was improved with sequential administration of SG and the PARPi talazoparib (Bardia AACR 2022). Here we report clinical outcomes from the phase II dose expansion cohort (NCT04039230). Methods: In a single-arm phase II study, adult patients with measurable mTNBC (per ASCO/CAP guidelines) were eligible. Starting dose was SG at 10mg/kg on days 1 and 8 with talazoparib 1mg on days 15-21. Growth factor (G-CSF) prophylaxis was required. The primary endpoint was the confirmed Objective Response Rate (ORR) calculated per RECIST v1.1 and secondary endpoints included progression-free survival (PFS) and overall survival (OS). The Clinical Benefit Rate (CBR) at 6 months was also measured. Results: From June 2021 to March 2023, 26 patients were enrolled. The median age was 54 (range, 35 to 81). Patients received a median of 2 prior therapy lines for metastatic disease (range, 0 to 7). 6/26 patients remain on treatment at time of data cutoff. Median PFS was 6.2 months (95% CI, 3.7 to 12.8), and median OS was 18.0 months (95% CI, 10.7 to not evaluable). The confirmed ORR was 30.1% (95% CI, 14 to 52) and the CBR at 6 months was 53.8% (95% CI, 33 to 73). Serious adverse events (AEs) were seen in 10 (38.5%) of patients; in 7 (26.9%) serious AEs were treatment related. The most common treatment related AEs were anemia (92.3%), neutropenia (88.5%), nausea (84.6%) fatigue (80.7%), and thrombocytopenia (65.3%). Grade ≥3 neutropenia and anemia were seen in 80.7% and 34.6% of cases, respectively. One or more dose reductions were required in 58.0% of patients. One patient with a germline BRCA mutation was treated for 625 days before disease progression. Updated biomarker and survival data will be presented at the meeting. Conclusions: In this single-arm phase II study, SG in combination with talazoparib was feasible and demonstrated preliminary evidence of efficacy. A randomized clinical trial is needed to determine if the SG-PARPi combination is superior to SG monotherapy. Clinical trial information: NCT04039230 .

Antibody-drug conjugates (ADC) in patients with advanced/metastatic HER2-low expressing breast cancer: A systematic review and meta-analysis.

e13174 Background: Historically, HER2-targeted therapies failed to improve survival of patients with HER2-low-expressing tumors. Recently, trastuzumab deruxtecan (T-DXd), an antibody-drug conjugate (ADC), demonstrated superior outcomes compared with treatment of physician´s choice (TPC) in this population. Other ADCs have also shown encouraging results, including sacituzumab govitecan (SG), MRG002, and RC48-ADC. Hence, we performed a systematic review and meta-analysis to assess the effectiveness of ADCs in patients with HER2-low advanced/metastatic (a/m) breast cancer (BC). Methods: We searched PubMed, Embase, and Cochrane databases and ASCO, ESMO, and SABCS websites for studies evaluating ADCs on patients with HER2-low a/mBC. Outcomes of interest were objective response rate (ORR); disease control rate (DCR); clinical benefit rate (CBR); progression-free survival (PFS); and overall survival (OS). We used R software (v.4.2.2) and random effects models for all analyses. Heterogeneity was assessed using I2 test. Results: Overall, 12 studies were included (3 real-world studies and 9 clinical trials), with 1,292 HER2-low a/mBC patients, 378 received TPC, and 914 received ADCs. Most were treated with T-DXd (63%, n=572), SG (29%, n=268), MRG002 (6%, n=56), and RC48-ADC (2%, n=18). Median age ranged from 48.1 to 58 years, and follow-up from 9.5 to 18.4 months. Patients treated with T-DXd achieved a significantly higher ORR and DCR compared to those who received SG, RC48-ADC, and MRG002 (Table). CBR was numerically higher in patients on T-DXd than those on SG but did not reach a significant difference. Patients with HR-positive tumors treated with SG had an ORR of 45% (95% CI 23 – 67%), and patients with pure HER2-low treated with any ADC, had an ORR of 38% (95% CI 30 – 45%). In the pooled analysis of 3 RCTs, ADCs significantly prolonged PFS compared with TPC (n=963, HR: 0.44, 95% CI 0.32 – 0.61, I2 = 66%, p<0.001), and OS (n= 680, HR: 0.56, 95% CI 0.36 – 0.89, I2 = 73%, p=0.015). Patients on ADCs also achieved a greater anti-tumor response than TPC, including better ORR (OR: 4.18, 95% CI 2.40 - 7.28, I2 = 52%, p<0.001), DCR (OR: 2.82, 95% CI 2.06 - 3.85, I2 = 7%, p<0.001), and CBR (OR: 3.41, 95% CI 2.36 - 4.93, I2 = 25%, p<0.001). Conclusions: Our systematic review and meta-analysis supports the efficacy of ADCs in HER2-low a/mBC patients over TPC. Future studies should focus on bringing ADCs into earlier lines of therapy in this population.Anti-tumor activity of ADCs presented as overall % (95% CI). [Table: see text]

Optimizing Solid Tumor Treatment with Antibody-drug Conjugates Using Agent-Based Modeling: Considering the Role of a Carrier Dose and Payload Class.

Antibody-drug conjugates (ADCs) show significant clinical efficacy in the treatment of solid tumors, but a major limitation to their success is poor intratumoral distribution. Adding a carrier dose improves both distribution and overall drug efficacy of ADCs, but the optimal carrier dose has not been outlined for different payload classes. In this work, we study two carrier dose regimens: 1) matching payload potency to cellular delivery but potentially not reaching cells farther away from blood vessels, or 2) dosing to tumor saturation but risking a reduction in cell killing from a lower amount of payload delivered per cell. We use a validated computational model to test four different payloads conjugated to trastuzumab to determine the optimal carrier dose as a function of target expression, ADC dose, and payload potency. We find that dosing to tumor saturation is more efficacious than matching payload potency to cellular delivery for all payloads because the increase in thenumber of cells targeted by the ADC outweighs the loss in cell killing on targeted cells. An important exception exists if the carrier dose reduces the payload uptake per cell to the point where all cell killing is lost. Likewise, receptor downregulation can mitigate the benefits of a carrier dose. Because tumor saturation and in vitro potency can be measured early in ADC design, these results provide insight into maximizing ADC efficacy and demonstrate the benefits of using simulation to guide ADC design.

Antibody-Drug Conjugates as Novel Therapeutic Agents for Non-Small Cell Lung Carcinoma with or without Alterations in Oncogenic Drivers.

Antibody-drug conjugates (ADCs) are an emerging class of therapeutics for lung cancer, and several are currently in development for this malignancy. The structure of these molecules is based on an antibody that targets a protein on the lung cancer cell surface and a cytotoxic payload attached by a linker. Many protein targets, including TROP2, c-MET, CEACAM5, HER2, and HER3 have been identified. In metastatic non-small cell lung carcinoma (NSCLC) without alterations in oncogenic drivers, platinum-based chemotherapy and immune checkpoint inhibitors (ICIs) targeting the programmed death-1/programmed death-ligand 1 (PD1/PDL1) interaction are the standard first-line treatments. In patients with EGFR-mutated or ALK-rearranged NSCLC, tyrosine kinase inhibitors (TKIs) are recommended. However, although the prognosis of patients with metastatic NSCLC differs between such with and without alterations in oncogenic drivers, most patients eventually experience disease progression. A novel therapeutic class is needed in routine practice to overcome the mechanisms of resistance to ICIs and EGFR/ALK TKIs. Several ADCs have already been approved for other cancers, such as breast cancer and urothelial carcinoma. This review summarizes the knowledge about the efficacy and tolerance profiles of ADCs targeting TROP2, HER2, HER3, CEACAM5 and c-MET in metastatic NSCLC with and without alterations in oncogenic drivers.

Abstract PO3-14-08: Metaplastic Breast Cancer: Whole Genome Sequencing Analysis and Emerging Therapeutic Targets

Abstract Background: Metaplastic breast cancer (MpBC) is a rare histologic subtype of triple negative breast cancer (TNBC) with an aggressive behavior and poor outcome. Previous studies by whole-exome and targeted sequencing showed that MpBCs display a dominant mutational signature 3, associated to homologous recombination (HR) deficiency (HRD). Tumors displaying HRD are associated with response to therapies causing double strand breaks. Nonetheless, MpBCs consistently display significantly lower rates of response to neoadjuvant chemotherapy than non-metaplastic TNBCs and effective therapeutic alternatives are an unmet clinical need. Here we sought to assess the HR features of MpBCs using whole-genome sequencing (WGS), and to evaluate the expression in MpBCs of antigens that are targets of novel antibody drug conjugates (ADCs) in common forms of breast cancer. In addition, we sought to assess the efficacy of ADCs and drugs targeting the DNA damage response (DDR) using preclinical MpBC models. Materials and Methods: We subjected 25 primary MpBC to WGS. HRDetect, the ‘gold standard’ tool for assessment of HRD, was utilized. Mutational signatures were inferred using Signal. 31 MpBCs were subjected to RNA-sequencing to assess the gene expression levels ADC targets compared to non-MpBCs from The Cancer Genome Atlas (TCGA). Efficiency of ADCs and DDR drugs was evaluated using the MpBC cell models HCC1806, BT549 and Hs578T in vitroand/or using HCC1806 xenografts in athymic mice in vivo. Results: Although the majority of MpBCs (13/25) displayed a dominant SBS mutational signature 3, only a small subset of cases (3/25) were classified as HRD by HRDetect. These three bona fide HRD cases were found to harbor bi-allelic inactivation of BRCA1 (n=2) or RAD51C (n=1), and displayed various genomic features of HRD, including deletions with microhomology, enrichment in tandem duplications, rearrangement signatures 3 and 5, and high large scale state transitions (LST) and telomeric allelic imbalance (NtAI) scores. Most MpBCs (22/25), however, were not classified as HRD by HRDetect displaying an incomplete HRD phenotype, with only partial genomic features of HRD. 52% of MpBCs (13/25) displayed APOBEC mutagenesis exposure, which was present in the three bona fide HRD MpBCs. RNA-sequencing analyses revealed detectable ERBB2 and TROP2 expression in all MpBCs interrogated, although at lower levels than in non-MpBCs from TCGA. The HCC1806, BT549 and Hs578T MpBC cell models were found to be sensitive to Sacituzumab Govitecan and Trastuzumab Deruxtecan (T-DXd) in cell viability and colony formation assays, and to T-DXd in vivo. These MpBC cell models were also found to be sensitive to DDR compounds, such as ATR, WEE1 and PKMYT1 inhibitors in vitro, alone and in combination with T-DXd or Sacituzumab Govitecan. Conclusions: Most MpBCs display an incomplete HRD genomic scar, except for those cases harboring bi-allelic inactivation of HRD genes. APOBEC mutagenesis is operative in MpBCs and co-exists with HRD. MpBCs express ERBB2 and TROP2, and MpBC cell models are sensitive to T-DXd and Sacituzumab govitecan, as well as DDR compounds, targeting the incomplete HRD phenotype of MpBCs, alone and in combination. Taken together, these findings warrant further studies in patients with MpBCs testing the therapeutic efficacy of agents targeting the incomplete HRD phenotype, as well as the expression of ADC targets in these aggressive rare forms of TNBCs. Citation Format: Fresia Pareja, Andrea Gazzo, Higinio Dopeso, David Brown, Pier Selenica, Yingjie Zhu, Juan Blanco-Heredia, Laxmi Gusain, Xin Pei, Giacomo Montagna, Nour Abuhadra, Hanna Y Wen, Edi Brogi, Nadeem Riaz, Sarat Chandarlapaty, Maurizio Scaltriti, Larry Norton, Simon Powell, Jorge Reis-Filho, Britta Weigelt. Metaplastic Breast Cancer: Whole Genome Sequencing Analysis and Emerging Therapeutic Targets [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-14-08.

Immunohistochemistry of Lung Cancer Biomarkers.

Immunohistochemical (IHC) staining represents a comparatively inexpensive testing method that is attractive as a potential alternative to molecular sequencing methods or fluorescence in situ hybridization for pulmonary biomarker testing. While a variety of IHC tests directed at actionable genetic alterations have been developed and evaluated since the advent of targeted therapy, specific antibody clones for anaplastic lymphoma kinase, ROS-1, and potentially neurotrophic tropmyosin receptor kinase have been the primary antibodies that provide sufficiently robust results to be utilized as either a primary testing or screening method to direct targeted therapy. Antibodies for a variety of other targets such as epidermal growth factor receptors, for example, have lacked sufficient sensitivity and specificity to cover the range of mutations that may occur and are generally not recommended in lieu of molecular testing with the exception of limited resource settings. IHC is also used as a predictive marker for response to immunotherapy through evaluation of programmed death ligand 1 expression. In addition, multiple antibody-drug conjugates (ADCs) are under investigation, designed to deliver drugs directly to tumor cells through binding to specific target antigens. Some ADCs have already received accelerated FDA approval, and IHC was incorporated in many clinical trials evaluating ADC efficacy. As such, it is anticipated that ADCs may have a companion diagnostic IHC to guide patient selection.

A novel bispecific antibody drug conjugate targeting HER2 and HER3 with potent therapeutic efficacy against breast cancer.

Antibody drug conjugate (ADC) therapy has become one of the most promising approaches in cancer immunotherapy. Bispecific targeting could enhance the efficacy and safety of ADC by improving its specificity, affinity and internalization. In this study we constructed a HER2/HER3-targeting bispecific ADC (BsADC) and characterized its physiochemical properties, target specificity and internalization in vitro, and assessed its anti-tumor activities in breast cancer cell lines and in animal models. The HER2/HER3-targeting BsADC had a drug to antibody ratio (DAR) of 2.89, displayed a high selectivity against the target JIMT-1 breast cancer cells in vitro, as well as a slightly higher level of internalization than HER2- or HER3-monospecific ADCs. More importantly, the bispecific ADC potently inhibited the viability of MCF7, JIMT-1, BT474, BxPC-3 and SKOV-3 cancer cells in vitro. In JIMT-1 breast cancer xenograft mice, a single injection of bispecific ADC (3 mg/kg, i.v.) significantly inhibited the tumor growth with an efficacy comparable to that caused by combined injection of HER2 and HER3-monospecific ADCs (3 mg/kg for each). Our study demonstrates that the bispecific ADC concept can be applied to development of more potent new cancer therapeutics than the monospecific ADCs.