ABBV-011, A Novel, Calicheamicin-Based Antibody-Drug Conjugate, Targets SEZ6 to Eradicate Small Cell Lung Cancer Tumors

Emerging advances in defining the molecular and therapeutic landscape of small-cell lung cancer

Small-cell lung cancer (SCLC) has traditionally been considered a recalcitrant cancer with a dismal prognosis, with only modest advances in therapeutic strategies over the past several decades. Comprehensive genomic assessments of SCLC have revealed that most of these tumours harbour deletions of the tumour-suppressor genes TP53 and RB1 but, in contrast to non-small-cell lung cancer, have failed to identify targetable alterations. The expression status of four transcription factors with key roles in SCLC pathogenesis defines distinct molecular subtypes of the disease, potentially enabling specific therapeutic approaches. Overexpression and amplification of MYC paralogues also affect the biology and therapeutic vulnerabilities of SCLC. Several other attractive targets have emerged in the past few years, including inhibitors of DNA-damage-response pathways, epigenetic modifiers, antibody-drug conjugates and chimeric antigen receptor T cells. However, the rapid development of therapeutic resistance and lack of biomarkers for effective selection of patients with SCLC are ongoing challenges. Emerging single-cell RNA sequencing data are providing insights into the plasticity and intratumoural and intertumoural heterogeneity of SCLC that might be associated with therapeutic resistance. In this Review, we provide a comprehensive overview of the latest advances in genomic and transcriptomic characterization of SCLC with a particular focus on opportunities for translation into new therapeutic approaches to improve patient outcomes.

Antibody-drug conjugates in lung and breast cancer: current evidence and future directions-a position statement from the ETOP IBCSG Partners Foundation

Following the approval of the first antibody-drug conjugates (ADCs) in the early 2000s, development has increased dramatically, with 14 ADCs now approved and >100 in clinical development. In lung cancer, trastuzumab deruxtecan (T-DXd) is approved in human epidermal growth factor receptor 2 (HER2)-mutated, unresectable or metastatic non-small-cell lung cancer, with ADCs targeting HER3 (patritumab deruxtecan), trophoblast cell-surface antigen 2 [datopotamab deruxtecan and sacituzumab govitecan (SG)] and mesenchymal-epithelial transition factor (telisotuzumab vedotin) in late-stage clinical development. In breast cancer, several agents are already approved and widely used, including trastuzumab emtansine, T-DXd and SG, and multiple late-stage trials are ongoing. Thus, in the coming years, we are likely to see significant changes to treatment algorithms. As the number of available ADCs increases, biomarkers (of response and resistance) to better select patients are urgently needed. Biopsy sample collection at the time of treatment selection and incorporation of translational research into clinical trial designs are therefore critical. Biopsy samples taken peri- and post-ADC treatment combined with functional genomics screens could provide insights into response/resistance mechanisms as well as the impact of ADCs on tumour biology and the tumour microenvironment, which could improve understanding of the mechanisms underlying these complex molecules. Many ADCs are undergoing evaluation as combination therapy, but a high bar should be set to progress clinical evaluation of any ADC-based combination, particularly considering the high cost and potential toxicity implications. Efforts to optimise ADC dosing/duration, sequencing and the potential for ADC rechallenge are also important, especially considering sustainability aspects. The ETOP IBCSG Partners Foundation are driving strong collaborations in this field and promoting the generation/sharing of databases, repositories and registries to enable greater access to data. This will allow the most important research questions to be identified and prioritised, which will ultimately accelerate progress and help to improve patient outcomes.

Olfactory neuroblastoma mimics molecular heterogeneity and lineage trajectories of small-cell lung cancer

The olfactory epithelium undergoes neuronal regeneration from basal stem cells and is susceptible to olfactory neuroblastoma (ONB), a rare tumor of unclear origins. Employing alterations in Rb1/Trp53/Myc (RPM), we establish a genetically engineered mouse model of high-grade metastatic ONB exhibiting a NEUROD1+ immature neuronal phenotype. We demonstrate that globose basal cells (GBCs) are a permissive cell of origin for ONB and that ONBs exhibit cell fate heterogeneity that mimics normal GBC developmental trajectories. ASCL1 loss in RPM ONB leads to emergence of non-neuronal histopathologies, including a POU2F3+ microvillar-like state. Similar to small-cell lung cancer (SCLC), mouse and human ONBs exhibit mutually exclusive NEUROD1 and POU2F3-like states, an immune-cold tumor microenvironment, intratumoral cell fate heterogeneity comprising neuronal and non-neuronal lineages, and cell fate plasticity-evidenced by barcode-based lineage tracing and single-cell transcriptomics. Collectively, our findings highlight conserved similarities between ONB and neuroendocrine tumors with significant implications for ONB classification and treatment.

The Evolving Scenario of ES-SCLC Management: From Biology to New Cancer Therapeutics

Small cell lung cancer (SCLC) is an aggressive neuroendocrine carcinoma accounting for 15% of lung cancers with dismal survival outcomes. Minimal changes in therapy and prognosis have occurred in SCLC for the past four decades. Recent progress in the treatment of extensive-stage disease (ES-SCLC) has been marked by incorporating immune checkpoint inhibitors (ICIs) into platinum-based chemotherapy, leading to modest improvements. Moreover, few second-line-and-beyond treatment options are currently available. The main limitation for the molecular study of SCLC has been the scarcity of samples, because only very early diseases are treated with surgery and biopsies are not performed when the disease progresses. Despite all these difficulties, in recent years we have come to understand that SCLC is not a homogeneous disease. At the molecular level, in addition to the universal loss of retinoblastoma (RB) and TP53 genes, a recent large molecular study has identified other mutations that could serve as targets for therapy development or patient selection. In recent years, there has also been the identification of new genetic subtypes which have shown us how intertumor heterogeneity exists. Moreover, SCLC can also develop intratumoral heterogeneity linked mainly to the concept of cellular plasticity, mostly due to the development of resistance to therapies. The aim of this review is to quickly present the current standard of care of ES-SCLC, to focus on the molecular landscapes and subtypes of SCLC, subsequently present the most promising therapeutic strategies under investigation, and finally recap the future directions of ongoing clinical trials for this aggressive disease which still remains a challenge.

Landscape and Treatment Options of Shapeshifting Small Cell Lung Cancer

Small cell lung cancer (SCLC) is a deadly neuroendocrine malignancy, notorious for its rapid tumor growth, early metastasis, and relatively "cold" immune environment. Only standard chemotherapies and a few immune checkpoint inhibitors have been approved for SCLC treatment, revealing an urgent need for novel therapeutic approaches. Moreover, SCLC has been recently recognized as a malignancy with high intratumoral and intertumoral heterogeneity, which explains the modest response rate in some patients and the early relapse. Molecular subtypes defined by the expression of lineage-specific transcription factors (ASCL1, NEUROD1, POU2F3, and, in some studies, YAP1) or immune-related genes display different degrees of neuroendocrine differentiation, immune cell infiltration, and response to treatment. Despite the complexity of this malignancy, a few biomarkers and targets have been identified and many promising drugs are currently undergoing clinical trials. In this review, we integrate the current progress on the genomic landscape of this shapeshifting malignancy, the characteristics and treatment vulnerabilities of each subtype, and promising drugs in clinical phases.

Comprehensive review on the elaboration of payloads derived from natural products for antibody-drug conjugates

Antibody-drug conjugates (ADCs) have arisen as a promising class of biotherapeutics for targeted cancer treatment, combining the specificity of monoclonal antibodies with the cytotoxicity of small-molecule drugs. The choice of an appropriate payload is crucial for the success development of ADCs, as it determines the therapeutic efficacy and safety profile. This review focuses on payloads derived from natural products, including cytotoxic agents, DNA-damaging agents, and immunomodulators. These offer several advantages such as diverse chemical structures, unique mechanism of actions, and potential for improved therapeutic index. Challenges and opportunities associated with their development were highlighted. This review underscores the significance of natural product payloads in the elaboration of ADCs, which serves as a valuable resource for researchers involved in developing and optimizing next-generation ADCs for cancer treatment.

Preclinical Characterization of Catabolic Pathways and Metabolism of ABBV-011, a Novel Calicheamicin-Based SEZ6-Targeting Antibody-Drug Conjugate

Antibody-drug conjugates (ADC) have gained momentum for treatment of cancers, with 14 ADCs currently approved for commercial use worldwide. Calicheamicin is one of the payloads contributing to this trend, being used for both gemtuzumab ozogamicin (GO; trade name: Mylotarg) and inotuzumab ozogamicin (IO; trade name: Besponsa). Here we discuss the catabolic pathway and metabolism of ABBV-011, a novel SEZ6-targeted, calicheamicin-based ADC being investigated for the treatment of small cell lung cancer (SCLC). Specifically, our investigation has found that disulfide bond cleavage in N-acetyl-γ-calicheamicin payload is a key liability that potentially impacts overall stability of the ADC. To our knowledge, there have been no reported observations of disulfide bond cleavage of calicheamicin ADCs. ABBV-011 utilizes a novel linker structure, leading to a distinct metabolic profile when compared with GO and IO. Despite this difference in linker structures, we propose that this liability may also be relevant for other calicheamicin ADCs. Multiple data sets supporting our investigation were acquired as part of the preclinical development of ABBV-011 and demonstrate the utility of in vitro experiments to characterize potential ADC candidates prior to clinical trials. SIGNIFICANCE STATEMENT: Several in vitro and in vivo stability studies of ABBV-011, a calicheamicin-based antibody-drug conjugate (ADC), identified circulating metabolites and catabolites and suggested that disulfide cleavage may be a key liability for the conjugated linker-payload. These observations may be relevant to other disulfide-linked ADCs such as gemtuzumab ozogamicin (Mylotarg) and inotuzumab ozogamicin (Besponsa), both of which have reported similar half-lives that possibly indicate instability.

Multifunctional nanoparticle-mediated combining therapy for human diseases

Combining existing drug therapy is essential in developing new therapeutic agents in disease prevention and treatment. In preclinical investigations, combined effect of certain known drugs has been well established in treating extensive human diseases. Attributed to synergistic effects by targeting various disease pathways and advantages, such as reduced administration dose, decreased toxicity, and alleviated drug resistance, combinatorial treatment is now being pursued by delivering therapeutic agents to combat major clinical illnesses, such as cancer, atherosclerosis, pulmonary hypertension, myocarditis, rheumatoid arthritis, inflammatory bowel disease, metabolic disorders and neurodegenerative diseases. Combinatorial therapy involves combining or co-delivering two or more drugs for treating a specific disease. Nanoparticle (NP)-mediated drug delivery systems, i.e., liposomal NPs, polymeric NPs and nanocrystals, are of great interest in combinatorial therapy for a wide range of disorders due to targeted drug delivery, extended drug release, and higher drug stability to avoid rapid clearance at infected areas. This review summarizes various targets of diseases, preclinical or clinically approved drug combinations and the development of multifunctional NPs for combining therapy and emphasizes combinatorial therapeutic strategies based on drug delivery for treating severe clinical diseases. Ultimately, we discuss the challenging of developing NP-codelivery and translation and provide potential approaches to address the limitations. This review offers a comprehensive overview for recent cutting-edge and challenging in developing NP-mediated combination therapy for human diseases.

Actionable Driver Events in Small Cell Lung Cancer

Small cell lung cancer (SCLC) stands out as the most aggressive form of lung cancer, characterized by an extremely high proliferation rate and a very poor prognosis, with a 5-year survival rate that falls below 7%. Approximately two-thirds of patients receive their diagnosis when the disease has already reached a metastatic or extensive stage, leaving chemotherapy as the remaining first-line treatment option. Other than the recent advances in immunotherapy, which have shown moderate results, SCLC patients cannot yet benefit from any approved targeted therapy, meaning that this cancer remains treated as a uniform entity, disregarding intra- or inter-tumoral heterogeneity. Continuous efforts and technological improvements have enabled the identification of new potential targets that could be used to implement novel therapeutic strategies. In this review, we provide an overview of the most recent approaches for SCLC treatment, providing an extensive compilation of the targeted therapies that are currently under clinical evaluation and inhibitor molecules with promising results in vitro and in vivo.

Unlocking New Horizons in Small-Cell Lung Cancer Treatment: The Onset of Antibody-Drug Conjugates

Small-cell lung cancer (SCLC) is a highly aggressive disease, accounting for about 15% of all lung cancer cases. Despite initial responses to chemoimmunotherapy, SCLC recurs and becomes resistant to treatment. Recently, antibody-drug conjugates (ADCs) have emerged as a promising therapeutic option for SCLC. ADCs consist of an antibody that specifically targets a tumor antigen linked to a cytotoxic drug. The antibody delivers the drug directly to the cancer cells, minimizing off-target toxicity and improving the therapeutic index. Several ADCs targeting different tumor antigens are currently being evaluated in clinical trials for SCLC. Despite the negative results of rovalpituzumab tesirine (Rova-T), other ADCs targeting different antigens, such as B7-H3, seizure-related homolog 6 (SEZ6), and CEACAM5, have also been investigated in clinical trials, including for SCLC, and their results suggest preliminary activity, either alone or in combination with other therapies. More recently, sacituzumab govitecan, an anti-TROP2 ADC, demonstrated promising activity in lung cancer, including SCLC. Furthermore, an anti-B7-H3 (CD276), ifinatamab deruxtecan (DS7300A), showed a high response rate and durable responses in heavily pretreated SCLC. Overall, ADCs represent an intriguing approach to treating SCLC, particularly in the relapsed or refractory setting. Further studies are needed to determine their efficacy and safety and the best location in the treatment algorithm for SCLC. In this review, we aim to collect and describe the results regarding the past, the present, and the future of ADCs in SCLC.

Small Cell Lung Cancer: Emerging Targets and Strategies for Precision Therapy

Small cell lung cancer is an aggressive subtype of lung cancer with limited treatment options. Precision medicine has revolutionized cancer treatment for many tumor types but progress in SCLC has been slower due to the lack of targetable biomarkers. This review article provides an overview of emerging strategies for precision therapy in SCLC. Targeted therapies include targeted kinase inhibitors, monoclonal antibodies, angiogenesis inhibitors, antibody-drug conjugates, PARP inhibitors, and epigenetic modulators. Angiogenesis inhibitors and DNA-damaging agents, such as PARP and ATR inhibitors, have been explored in SCLC with limited success to date although trials are ongoing. The potential of targeting DLL3, a NOTCH ligand, through antibody-drug conjugates, bispecific T-cell engagers, and CAR T-cell therapy, has opened up new therapeutic options moving forward. Additionally, new research in epigenetic therapeutics in reversing transcriptional repression, modulating anti-tumor immunity, and utilizing antibody-drug conjugates to target cell surface-specific targets in SCLC are also being investigated. While progress in precision therapy for SCLC has been challenging, recent advancements provide optimism for improved treatment outcomes. However, several challenges remain and will need to be addressed, including drug resistance and tumor heterogeneity. Further research and biomarker-selected clinical trials are necessary to develop effective precision therapies for SCLC patients.