Antibody-drug Conjugate Research Articles

The Efficacy and Management of Antibody-Drug Conjugate

The Efficacy and Management of Antibody-Drug Conjugate

Beyond ADCs: Harnessing Bispecific Antibodies to Directly Induce Apoptosis for Targeted Tumor Eradication

Abstract Bispecific Apoptosis Triggers (BATs) are innovative bispecific antibodies designed to simultaneously target both a tumor-associated antigen and a cancer cell’s death receptor thereby directly activating the extrinsic apoptotic pathway to induce death of cancer cells. This unique mechanism distinguishes BATs from antibody-drug conjugates (ADCs), which rely on cytotoxic drugs, and bispecific immune cell engagers such as bispecific T-cell engagers (BiTEs) and bispecific natural killer cell engagers (NKCEs), which recruit immune cells to eliminate target cancer cells. BATs offer significant potential advantages in clinical efficacy and safety over ADCs and BiTEs. Although the field is still emerging, recent advancements are highly promising, and analysis of preclinical and clinical data of DR5-targeting antibodies have been pivotal in outlining the criteria for the next generation of effective and safe medicines. Antibodies found inactive in preclinical testing were also found to be clinically ineffective, whereas antibodies with minimal preclinical results demonstrated moderate clinical activity. All clinical DR5 targeting antibodies were well tolerated by patients even at high doses (with the exception of TAS266 due to its unique design). These findings underscore the predictive value of robust preclinical models on clinical outcomes. Notably, first-in-class BAT, Cancerlysin™ IMV-M, demonstrated potent efficacy in diverse xenograft cancer models and safety in non-human primates, marking a significant advancement in developing safe and effective anti-cancer drugs.

Platinum Resistance in Ovarian Cancer: Is This the End of the Line?

Approximately 80% of females with ovarian cancer are diagnosed with advanced disease, and around 70% of these females relapse within 3 years of first-line treatment. Five-year survival for newly diagnosed advanced ovarian cancer is less than 50%. Platinum-based chemotherapy is the cornerstone of systemic treatment; however, it is not appropriate for patients with relapsed ovarian cancer who had disease progression during previous platinum treatment, early symptomatic progression post-platinum treatment, or who are platinum intolerant. New drugs are needed to address the unmet need in patients with relapsed ovarian cancer who are not eligible for platinum-based chemotherapy. This article presents highlights from a satellite symposium conducted as part of the European Society for Medical Oncology (ESMO) Congress 2024, which took place from 13th–17th September 2024 in Barcelona, Spain. The objectives of the symposium were to improve understanding of the current treatment pathways and unmet needs for patients with ovarian cancer who are ineligible for platinum-based therapies, to raise awareness of the rationale for targeting folate receptor α (FRα) in a variety of novel therapeutics for platinum-resistant ovarian cancer (PROC), and to review the efficacy outcomes and side effects from recent clinical trials involving antibody–drug conjugates (ADC) in PROC. In this symposium, Ana Oaknin, Vall d’Hebron University Hospital, Barcelona, Spain, described the current landscape in advanced ovarian cancer and the unmet need in relapsed disease; Philipp Harter, Evangelische Kliniken Essen-Mitte, Germany, explored FRα-targeted therapeutics in PROC; and Kathleen Moore, Stephenson Cancer Center, University of Oklahoma, Norman, USA, discussed ADC development beyond FRα in PROC. The symposium concluded with a lively discussion, including questions from the audience, key examples of which are included in this article.

TROPION-Lung07: Phase III study of Dato-DXd+pembrolizumab±platinum-based chemotherapy as 1L therapy for advanced non-small-cell lung cancer.

For patients with advanced/metastatic non-small-cell lung cancer (NSCLC) without actionable genomic alterations and low (<50%) PD-L1 expression, pembrolizumab plus pemetrexed and platinum chemotherapy is a preferred first-line treatment. These patients have comparatively worse outcomes than those with higher PD-L1 expression, underscoring the need for new combination strategies. Datopotamab deruxtecan (Dato-DXd), a TROP2-directed antibody-drug conjugate, has demonstrated encouraging antitumor activity and safety in this patient population. We describe the rationale and design of TROPION-Lung07, a randomized, open-label Phase III study assessing Dato-DXd in combination with pembrolizumab with/without platinum-based chemotherapy versus pembrolizumab plus pemetrexed and platinum-based chemotherapy in patients with advanced/metastatic non-squamous NSCLC without actionable genomic alterations and <50% PD-L1 expression. Primary study objectives are progression-free survival and overall survival.Clinical Trial Registration: NCT05555732 (ClinicalTrials.gov).

Therapeutic targeting of the protein tyrosine kinase-7 in cancer: an overview.

The protein tyrosine kinase-7 (PTK7) is an evolutionarily conserved transmembrane receptor that has emerged as a potential therapeutic target for human tumors. PTK7 is a pseudokinase that is involved in the modulation of the Wnt signaling pathway through interactions with other receptors. These interactions result in targeted gene activation that regulates cell polarity, migration, and proliferation during embryogenesis. Aside of this role during development, PTK7 has been shown as overexpressed in numerous cancers including colon carcinoma, leukemia, neuroblastoma, hepatoma, and ovarian cancer. The activity of PTK7 and the direct correlation with poor prognosis have fostered preclinical investigations and phase I clinical trials, aiming at inhibiting PTK7 and inducing antitumoral effects. In this review, we provide an exhaustive overview of the diverse approaches that use PTK7 as a new molecular target for cancer therapy in different tumor types. We discuss current therapies and future strategies including chimeric antigen receptor-T cells, antibody-drug conjugates, aptamers, based on up-to-date literature and ongoing research progress.

Advances in Cancer Treatment: Harnessing Antibody-Drug Conjugates and Oncolytic Viruses for Targeted Therapy

Effective cancer treatment remains a major challenge due to its heterogeneity and complexity. However, emerging therapies such as antibody-drug conjugates (ADCs) and oncolytic viruses show great potential in leveraging the body's natural defenses to selectively target and destroy cancer cells. These promising treatments have demonstrated encouraging results in clinical trials, and ongoing research and development are expected to further enhance their efficacy and improve patient outcomes.

Evaluation of Potency and Specificity of Cryptophycin-Loaded Antibody-Drug Conjugates.

An enhanced variant of the antimitotic toxin cryptophycin was conjugated to the anti-Her2 monoclonal antibody (mAb) Trastuzumab upon Michael addition. Either antibodies with freed hinge-region cysteines or THIOMAB formats with engineered cysteines in the mAbs light chain were added to a maleimide derivative of cryptophycin. These Antibody-Drug Conjugates (ADCs) showed retained binding to Her2 positive tumor cells and highly efficient cell killing in double-digit pM range on high Her2-expressing SK-BR-3 cells. Two ADCs (DAR6, DAR3) showed superior cell killing of the cell lines JIMT-1 and RT112 with medium receptor expression level in comparison with a DAR6 MMAE ADC serving as reference. The observed cell cytotoxicity is target-dependent since no impact on cell viability was observed for low Her2-expressing MDA-MB468 cells. Particularly the DAR3 ADC in THIOMAB format exhibiting desirable biophysical properties and high potency emerged as a promising candidate for further in vivo investigations.

Understanding the chemistry & pharmacology of antibody-drug conjugates in triple-negative breast cancer with special reference to exatecan derivatives.

In the spectrum of breast malignancies, triple-negative breast cancer is the most widely spreading subtype of breast cancer due to a low availability of therapeutic remedies. Recently, antibody-drug conjugates dramatically resolved the landscape for the treatment of triple-negative breast cancer. This review mainly focuses on the chemistry, structure, mechanism of action, and role of antibody-drug conjugates in triple-negative breast cancer. Datopotecan Deruxtecan (Dato-DXd) is a new-generation ADC showing encouraging results for TNBC. In this review, we have also emphasized TROP-2-directed Datopotamab deruxtecan ADCs to treat triple-negative breast cancer, its synthesis, mechanism of action, pharmacokinetics, pharmacodynamics, adverse events, and their ongoing clinical trials.

Potential mechanisms of interstitial lung disease induced by antibody-drug conjugates based on quantitative analysis of drug distribution.

Antibody-drug conjugates (ADCs) are a rapidly advancing category of therapeutic agents with notable anti-cancer efficacy. However, the emergence of interstitial lung disease (ILD) as a severe ADC-associated adverse event highlights the need to better understand the underlying mechanisms. In this study, xenograft model mice with tumors expressing different levels of the trophoblast antigen 2 (TROP2) were generated by subcutaneously transplanting the various TROP2-expression cancer lines. The mice received different doses of TROP2-eribulin, a novel TROP2-targeting ADC, composed of an anti-TROP2 antibody and the eribulin payload, joined by a cleavable linker. The concentration and distribution of TROP2-eribulin, as well as the pharmacokinetics of eribulin release, were assessed in tumor and lung tissues. Analysis of tumor tissue showed that the concentration of released eribulin was approximately 10-fold higher in NCI-H2110 (high TROP2 expression) than in A549 (low TROP2 expression), while analysis of lung tissue showed that TROP2-eribulin was distributed in lung tissue in a dose-dependent manner of TROP2-eribulin regardless of TROP2 expression, with significantly more eribulin released in the high-dose group than in the other dose groups (P < 0.05). Immunofluorescence assay analysis showed that TROP2-eribuilin localized to alveolar macrophages. In the analysis using human- leukemia monocytic cell, the concentration of eribulin released from TROP2-eribuilin was significantly reduced by the use of an Fc receptor inhibitor (P < 0.05). These results revealed that Fcγ-receptor-mediated uptake by alveolar macrophages releases cytotoxic payload into lung tissue, helping to clarify the pathogenesis of ADC-induced ILD.

Perioperative systemic therapy, current paradigm and ongoing clinical trials in upper tract urothelial cancer.

To provide of comprehensive overview of existing and future paradigms for perioperative systemic therapy in the treatment of upper tract urothelial carcinoma. Contemporary treatment paradigms for the management of upper tract urothelial carcinoma focus on use of neoadjuvant cisplatin based chemotherapy for high grade disease primarily based on two small single arm phase II clinical trials. More robust evidence from a phase III randomized clinical trial exists for the use of adjuvant platinum based chemotherapy for invasive disease after radical nephroureterectomy, but there are significant concerns about renal function and platinum eligibility after nephroureterectomy. There are currently ongoing clinical trials for nonplatinum based perioperative systemic therapies including checkpoint inhibitors/immunotherapy as well as antibody-drug conjugates, but currently no recommendation can be made for these approaches. Current evidence supports neoadjuvant cisplatin chemotherapy in the setting of high grade disease or concern for significant renal dysfunction after radical nephroureterectomy or platinum based adjuvant chemotherapy in eligible patients with advanced disease after surgery. While there is no established role for nonplatinum based therapies yet, multiple ongoing trials exploring use of immunotherapies and antibody-drug conjugates as monotherapy or combination may provide new therapeutic options in this population.

The impact of HER2-low status on pathological complete response and disease-free survival in early-stage breast cancer

BackgroundThe HER-2 status of breast cancer (BC) has been classified as negative or positive for a long time. Given the efficacy of novel anti-HER2-targeted antibody drug conjugates (ADCs) in HER2-low BC, a distinct subgroup of HER2-low tumors has emerged within BC. The biology and prognostic impact of HER2-low expression are not yet well defined, and inconsistent results were reported. This study aims to evaluate the impact of low HER-2 status on the response to neoadjuvant chemotherapy (NACT) and disease- free survival (DFS) rates.MethodsWe retrospectively analyzed BC patients treated with NACT from 2017 to 2023 in two cancer centers. HER2-negative patients were included. HER-2 low status was defined by IHC + 1 or + 2/ISH non-amplified, and HER2-zero was defined by IHC 0. Pathological complete response (pCR) rates and DFS between HER2-low and HER2-zero populations were compared.Results170 patients were identified. 122 (72%) of these patients were HER2- zero BC, whereas 48 (28%) were HER2-low BC. Overall, pCR was achieved in 35 (20.5%) patients. Of these, pCR was observed in 30 patients (44.6%) from the HER2- zero group, compared to 5 patients (10.4%) from the HER2-low group (p = 0.046), but significance was lost in multivariate analysis. Among the hormone receptor (HR) positive subtype, pCR was achieved 19.8% of HER2-zero tumors and 7.5% of HER2-low tumors (p = 0.08). For HR-negative subtype 34.1% HER2-zero tumors had pCR and 25% of the HER2-low tumors had pCR (p = 0.614). There was no association between DFS and HER2-low status.ConclusionsOur study indicates that HER2-low status had no impact on pCR or DFS.

Comprehensive insights into glioblastoma multiforme: drug delivery challenges and multimodal treatment strategies.

Glioblastoma multiforme (GBM) is one of the most common and malignant brain tumors, with a high prevalence in elderly population. Most chemotherapeutic agents fail to reach the tumor site due to various challenges. However, smart nanocarriers have demonstrated excellent drug-loading capabilities, enabling them to cross the blood brain tumor barrier for the GBM treatment. Surface modification of nanocarriers has significantly enhanced their potential for targeting therapeutics. Moreover, recent innovations in drug therapies, such as the incorporation of theranostic agents in nanocarriers and antibody-drug conjugates, have offered newer insights for both diagnosis and treatment. This review focuses on recent advances in new therapeutic interventions for GBM, with an emphasis on the nanotheranostics systems to maximize therapeutic and diagnostic outcomes.

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.

Evaluation of Double Self-Immolative Linker-Based Antibody-Drug Conjugate FDA022-BB05 with Enhanced Therapeutic Potential.

Typical antibody-drug conjugates (ADCs) with valine-alanine linkage, often conjugated with the amino group in payloads, face challenges when interacting with hydroxyl group-containing payloads. Herein, we introduced a transformative Val-Ala-based double self-immolative linker-payload platform, reshaping ADCs by optimizing hydroxyl group-containing payload integration. Utilizing this platform, FDA022-BB05 was successfully conjugated with the hydroxyl group-containing payload DXd using trastuzumab (FDA022) as the monoclonal antibody (mAb). FDA022-BB05 demonstrated enhanced stability, effective cathepsin B sensitivity, reduced cell proliferation, increased bystander killing, and targeted delivery. Notably, acute toxicity evaluations in diverse preclinical models indicated favorable safety profiles and tolerability, with a broad therapeutic index in HER2-positive and -negative xenografts. Overall, these compelling findings support the promising therapeutic potential of FDA022-BB05, emphasizing the significance of diverse linker-payload platform strategies. This ADC is a valuable addition to targeted cancer therapy development, currently advancing through phase I clinical trials.

ETx-22: a novel nectin-4-directed antibody drug conjugate, demonstrates safety and potent antitumor activity in low nectin-4 expressing tumors.

Nectin-4 is a cell-adhesion molecule expressed at various levels in many solid tumors, including urothelial cancer. As means to reduce on-target skin toxicity observed with enfortumab vedotin, an anti-nectin-4-MMAE ADC approved for patients with advanced urothelial cancer, 15A7.5, an anti-nectin-4 monoclonal antibody that exhibited differential nectin-4 binding between tumor and primary keratinocytes, was selected for the development of ETx-22. Exatecan, a topoisomerase I inhibitor, was chosen as payload. ETx-22 ADC induced rapid and long-lasting tumor regression in various patient derived xenograft models expressing low to high levels of nectin-4 and also in MonoMethyl Auristatin-E resistant xenograft model. ETx-22 has a highest non severely toxic dose of over 20 mg/kg in non-human primates without signs of important skin toxicity. ETx-22 represents a valuable therapy, for the treatment of patients with nectin-4 expressing tumors including those that have become resistant to enfortumab vedotin treatment.

Tumor Biology Hides Novel Therapeutic Approaches to Diffuse Large B-Cell Lymphoma: A Narrative Review

Diffuse large B-cell lymphoma (DLBCL) is a malignancy of immense biological and clinical heterogeneity. Based on the transcriptomic or genomic approach, several different classification schemes have evolved over the years to subdivide DLBCL into clinically (prognostically) relevant subsets, but each leaves unclassified samples. Herein, we outline the DLBCL tumor biology behind the actual and potential drug targets and address the challenges and drawbacks coupled with their (potential) use. Therapeutic modalities are discussed, including small-molecule inhibitors, naked antibodies, antibody–drug conjugates, chimeric antigen receptors, bispecific antibodies and T-cell engagers, and immune checkpoint inhibitors. Candidate drugs explored in ongoing clinical trials are coupled with diverse toxicity issues and refractoriness to drugs. According to the literature on DLBCL, the promise for new therapeutic targets lies in epigenetic alterations, B-cell receptor and NF-κB pathways. Herein, we present putative targets hiding in lipid pathways, ferroptosis, and the gut microbiome that could be used in addition to immuno-chemotherapy to improve the general health status of DLBCL patients, thus increasing the chance of being cured. It may be time to devote more effort to exploring DLBCL metabolism to discover novel druggable targets. We also performed a bibliometric and knowledge-map analysis of the literature on DLBCL published from 2014–2023.

Trastuzumab Duocarmazine in Pretreated Human Epidermal Growth Factor Receptor 2-Positive Advanced or Metastatic Breast Cancer: An Open-Label, Randomized, Phase III Trial (TULIP).

Human epidermal growth factor receptor 2 (HER2)-targeted therapy is standard of care for HER2-positive (HER2+) breast cancer, but most patients develop progressive disease with persistent HER2 expression. No definitive treatment guidance currently exists beyond second line. Trastuzumab duocarmazine (T-Duo) is a third-generation, HER2-targeted antibody-drug conjugate that demonstrated efficacy and acceptable safety in phase I studies of heavily pretreated patients with HER2+/HER2-low breast cancer. In this open-label, randomized, phase III trial, T-Duo was compared with physician's choice (PC) in patients with unresectable locally advanced/metastatic HER2+ breast cancer with progression during/after ≥2 HER2-targeted therapies or after trastuzumab emtansine (T-DM1). The primary endpoint was progression-free survival (PFS) by blinded independent central review. In total, 437 patients were randomly assigned 2:1 to T-Duo (n = 291) or PC (n = 146). The median age was 56.0 years (range, 24-86); most patients (93.6%) had metastatic disease. The median time from diagnosis of metastatic disease to trial entry was 3.5 years; the median number of prior HER2-targeted therapies in metastatic setting was three. The median PFS was 7.0 months (95% CI, 5.4 to 7.2) with T-Duo versus 4.9 months (95% CI, 4.0 to 5.5; hazard ratio [HR], 0.64 [95% CI, 0.49 to 0.84]; P = .002) with PC. PFS benefit was maintained across most predefined subgroups. The median overall survival (first analysis) was 20.4 (T-Duo) versus 16.3 months (PC; HR, 0.83 [95% CI, 0.62 to 1.09]; P = .153). Objective response rate was 27.8% (T-Duo) versus 29.5% (PC); other efficacy end points-clinical benefit rate, duration of response, and reduction in target lesion measurement-tended to favor T-Duo. Grade ≥3 treatment-emergent adverse events occurred in 52.8% (T-Duo) versus 48.2% (PC). Treatment with T-Duo was manageable, but tolerability was affected by prevalent ocular toxicity, leading to a higher discontinuation rate in the T-Duo arm. T-Duo significantly reduced the risk of progression in patients with advanced HER2+ breast cancer who have progressed during/after ≥2 HER2-targeted therapies or after T-DM1.

A proteogenomic surfaceome study identifies DLK1 as an immunotherapeutic target in neuroblastoma

Cancer immunotherapies produce remarkable results in B cell malignancies; however, optimal cell surface targets for many solid cancers remain elusive. Here, we present an integrative proteomic, transcriptomic, and epigenomic analysis of tumor and normal tissues to identify biologically relevant cell surface immunotherapeutic targets for neuroblastoma, an often-fatal childhood cancer. Proteogenomic analyses reveal sixty high-confidence candidate immunotherapeutic targets, and we prioritize delta-like canonical notch ligand 1 (DLK1) for further study. High expression of DLK1 directly correlates with a super-enhancer. Immunofluorescence, flow cytometry, and immunohistochemistry show robust cell surface expression of DLK1. Short hairpin RNA mediated silencing of DLK1 in neuroblastoma cells results in increased cellular differentiation. ADCT-701, a DLK1-targeting antibody-drug conjugate (ADC), shows potent and specific cytotoxicity in DLK1-expressing neuroblastoma xenograft models. Since high DLK1 expression is found in several adult and pediatric cancers, our study demonstrates the utility of a proteogenomic approach and credentials DLK1 as an immunotherapeutic target.

A Sequential Population Pharmacokinetic Model of Zilovertamab Vedotin in Patients with Hematologic Malignancies Extrapolated to the Pediatric Population.

Recently a number of antibody-drug conjugate (ADC) pharmacometric models have been reported in the literature, describing one or two ADC-related analytes. The objective of this analysis was to build a population pharmacokinetic (popPK) three-analyte ADC model to describe efficacy and safety of zilovertamab vedotin, an ROR1-targeting ADC conjugated to monomethyl auristatin E (MMAE). Data from a phase 1 study of zilovertamab vedotin in subjects with hematologic malignancies was used in a stepwise ADC modeling strategy based on the simplified ADC popPK model proposed by Gibiansky. This choice provided opportunity to model three analytes: conjugated monomethyl auristatin E (acMMAE), total monoclonal antibody (total mAb), and free MMAE. The model was extrapolated to the pediatric population using a clearance maturation function and accounting for weight dependent pharmacokinetic (PK) changes. The simplified model provided a good structure to fit the adult acMMAE, total mAb, and free MMAE data. Analysis showed that MMAE was released through deconjugation of the payload and full proteolytic degradation of the acMMAE. Deconjugation was associated with an immediate release of MMAE, proteolytic clearance introduced a delay in the release of MMAE. Simulation of the model extrapolated to the pediatric population was the basis for pediatric dosing strategies forzilovertamab vedotinthat were approved in the United States and European Union. The total mAb, acMMAE, and free MMAE model showed a good fit to the data. The pediatric population can match the acMMAE adult exposure at the same weight-based dose regimen without concerns that the toxic MMAE concentration will reach higher levelsthan found in adults.

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.