Emerging therapies targeting the delta-like ligand 3 (DLL3) in small cell lung cancer

Ferroptosis: Potential therapeutic targets and prognostic predictions for acute myeloid leukemia (Review)

Ferroptosis is a relatively recently discovered type of regulated cell death that is induced by iron-dependent lipid peroxidation. The key contributing factors to ferroptosis are the loss of glutathione peroxidase 4 which is required for reversing lipid peroxidation, the buildup of redox-active iron and the oxidation of phospholipids containing polyunsaturated fatty acids. Ferroptosis has been associated with a number of diseases, including cancers such as hepatocellular carcinoma, breast cancer, acute renal damage and neurological disorders such as Alzheimer's disease and Alzheimer's disease, and there may be an association between ferroptosis and acute myeloid leukemia (AML). The present review aims to describe the primary regulatory pathways of ferroptosis, and the relationship between ferroptosis and the occurrence and development of AML. Furthermore, the present review comprehensively summarizes the latest advances in the treatment and prognosis of ferroptosis in AML.

Emerging Nanomedicine Approaches in Targeted Lung Cancer Treatment

Lung cancer, the leading cause of cancer-related deaths worldwide, is characterized by its aggressive nature and poor prognosis. As traditional chemotherapy has the disadvantage of non-specificity, nanomedicine offers innovative approaches for targeted therapy, particularly through the development of nanoparticles that can deliver therapeutic agents directly to cancer cells, minimizing systemic toxicity and enhancing treatment efficacy. VEGF and VEGFR are shown to be responsible for activating different signaling cascades, which will ultimately enhance tumor development, angiogenesis, and metastasis. By inhibiting VEGF and VEGFR signaling pathways, these nanotherapeutics can effectively disrupt tumor angiogenesis and proliferation. This review highlights recent advancements in nanoparticle design, including lipid-based, polymeric, and inorganic nanoparticles, and their clinical implications in improving lung cancer outcomes, exploring the role of nanomedicine in lung cancer diagnoses and treatment.

Lung Cancer Research and Treatment: Global Perspectives and Strategic Calls to Action

BACKGROUND

Lung cancer remains a critical public health issue, presenting multifaceted challenges in prevention, diagnosis, and treatment. This article aims to review the current landscape of lung cancer research and management, delineate the persistent challenges, and outline pragmatic solutions.

MATERIALS AND METHODS

Global experts from academia, regulatory agencies such as the Food and Drug Administration (FDA) and the European Medicines Agency (EMA), the National Cancer Institute (NCI), professional societies, the pharmaceutical and biotech industries, and patient advocacy groups were gathered by the New York Lung Cancer Foundation to review the state of the art in lung cancer and to formulate calls to action.

RESULTS

Improving lung cancer management and research involves promoting tobacco cessation, identifying individuals at risk who could benefit from early detection programs, and addressing treatment-related toxicities. Efforts should focus on conducting well-designed trials to determine the optimal treatment sequence. Research into innovative biomarkers and therapies is crucial for more personalized treatment. Ensuring access to appropriate care for all patients, whether enrolled in clinical trials or not, must remain a priority.

CONCLUSIONS

Lung cancer is a major health burden worldwide, and its treatment has become increasingly complex over the past two decades. Improvement in lung cancer management and research requires unified messaging and global collaboration, expanded education, and greater access to screening, biomarker testing, treatment, as well as increased representativeness, participation, and diversity in clinical trials.

Relationship between the expressions of DLL3, ASC1, TTF-1 and Ki-67: First steps of precision medicine at SCLC

This study presents an observational, cross-sectional analysis of 64 patients diagnosed with small cell lung cancer (SCLC) at a reference laboratory for thoracic pathology between 2022 and 2024. The primary objective was to evaluate the expression of Delta-like ligand 3 (DLL3) and other neuroendocrine markers such as Chromogranin, and Synaptophysin, utilizing both traditional immunohistochemistry and digital pathology tools. Patients were primarily older adults, with a median age of over 71, and most biopsies were obtained from lung parenchyma. Immunohistochemistry (IHC) was performed using specific monoclonal antibodies, with DLL3 showing variable expression across the samples. Notably, DLL3 was expressed in 72.3% of the cases, with varied intensities and a semi-quantitative H-score applied for more nuanced analysis. ASCL1 was expressed in 97% of cases, with the majority considered low-expressors. Only 11% had high expression. TTF-1, traditionally not a conventional marker for the diagnosis of SCLC, was positive in half of the cases, suggesting its potential as a biomarker. The study underscores the significant variability in the expression of neuroendocrine markers in SCLC, with implications for both diagnosis and potential therapeutic targeting. DLL3, particularly, shows promise as a therapeutic target due to its high expression rate in the cohort. The use of digital pathology software QuPath enhanced the accuracy and depth of analysis, allowing for detailed morphometric analysis and potentially informing more personalized treatment approaches. The findings emphasize the need for further research into the role of these markers in the management and treatment of SCLC, considering the poor prognosis and high mortality rate observed in the cohort.

Tarlatamab-dlle: A New Hope for Patients with Extensive-Stage Small-Cell Lung Cancer

OPINION STATEMENT

Lung cancer is expected to contribute to about 0.234 million new cases and about 0.125 million mortalities in the United States in the year 2024. Small cell lung cancer (SCLC), a neuroendocrine carcinoma, has lesser prevalence but is more aggressive at an extensive stage where the tumor is not only confined to hemithorax, mediastinum, and supraclavicular region but spread beyond the supraclavicular region. The prognosis of SCLC, irrespective of the limited or extensive stage, is very poor. Only a 5-10% overall survival rate in five years is expected and with extensive-stage SCLC, long-term disease-free survival is rare. In May 2024, the USFDA approved Tarlatamab-dlle, a DLL3 targeted bi-specific T-cell engager, for treating extensive-stage SCLC in adult patients, on or after platinum-based chemotherapy or on progression. Before the approval of Tarlatamab-dlle, only a few drugs, such as Atezolizumab and Durvalumab, received FDA approval for treating extensive-stage SCLC. It might be possible that Tarlatamab-dlle received accelerated FDA approval for extensive-stage SCLC, leaving some questions unanswered at this stage. This manuscript is focused on clinical, pre-clinical, and other pharmacological aspects of Tarlatamab-dlle for extensive-stage SCLC.

Activating Invasion and Metastasis in Small Cell Lung Cancer: Role of the Tumour Immune Microenvironment and Mechanisms of Vasculogenesis, Epithelial-Mesenchymal Transition, Cell Migration, and Organ Tropism

BACKGROUND

Small cell lung cancer (SCLC) harbours the most aggressive phenotype of all lung cancers to correlate with its bleak prognosis. The aggression of SCLC is partially attributable to its strong metastatic tendencies. The biological processes facilitating the metastasis in SCLC are still poorly understood and garnering a deeper understanding of these processes may enable the exploration of additional targets against this cancer hallmark in the treatment of SCLC.

RECENT FINDINGS

This narrative review will discuss the proposed molecular mechanisms by which the cancer hallmark of activating invasion and metastasis is featured in SCLC through important steps of the metastatic pathway, and address the various molecular targets that may be considered for therapeutic intervention. The tumour immune microenvironment plays an important role in facilitating immunotherapy resistance, whilst the poor infiltration of natural killer cells in particular fosters a pro-metastatic environment in SCLC. SCLC vasculogenesis is achieved through VEGF expression and vascular mimicry, and epithelial-mesenchymal transition is facilitated by the expression of the transcriptional repressors of E-cadherin, the suppression of the Notch signalling pathway and tumour heterogeneity. Nuclear factor I/B, selectin and B1 integrin hold important roles in SCLC migration, whilst various molecular markers are expressed by SCLC to assist organ-specific homing during metastasis. The review will also discuss a recent article observing miR-1 mRNA upregulation as a potential therapeutic option in targeting the metastatic activity of SCLC.

CONCLUSION

Treatment of SCLC remains a clinical challenge due to its recalcitrant and aggressive nature. Amongst the many hallmarks used by SCLC to enable its aggressive behaviour, that of its ability to invade surrounding tissue and metastasise is particularly notable and understanding the molecular mechanisms in SCLC metastasis can identify therapeutic targets to attenuate SCLC aggression and improve mortality.

FZ-AD005, a Novel DLL3-Targeted Antibody-Drug Conjugate with Topoisomerase I Inhibitor, Shows Potent Antitumor Activity in Preclinical Models

Delta-like ligand 3 (DLL3) is overexpressed in small cell lung cancer (SCLC) and has been considered an attractive target for SCLC therapy. Rovalpituzumab tesirine was the first DLL3-targeted antibody-drug conjugate (ADC) to enter clinical studies. However, serious adverse events limited progress in the treatment of SCLC with rovalpituzumab tesirine. In this study, we developed a novel DLL3-targeted ADC, FZ-AD005, by using DXd with potent cytotoxicity and a relatively better safety profile to maximize the therapeutic index. FZ-AD005 was generated by a novel anti-DLL3 antibody, FZ-A038, and a valine-alanine (Val-Ala) dipeptide linker to conjugate DXd. Moreover, Fc-silencing technology was introduced in FZ-AD005 to avoid off-target toxicity mediated by FcγRs and showed negligible Fc-mediated effector functions in vitro. In preclinical evaluation, FZ-AD005 exhibited DLL3-specific binding and demonstrated efficient internalization, bystander killing, and excellent in vivo antitumor activities in cell line-derived xenograft and patient-derived xenograft models. FZ-AD005 was stable in circulation with acceptable pharmacokinetic profiles in cynomolgus monkeys. FZ-AD005 was well tolerated in rats and monkeys. The safety profile of FZ-AD005 was favorable, and the highest nonseverely toxic dose was 30 mg/kg in cynomolgus monkeys. In conclusion, FZ-AD005 has the potential to be a superior DLL3-targeted ADC with a wide therapeutic window and is expected to provide clinical benefits for the treatment of patients with SCLC.

Small cell lung cancer profiling: an updated synthesis of subtypes, vulnerabilities, and plasticity

Small cell lung cancer (SCLC) is a devastating disease with high proliferative and metastatic capacity. SCLC has been classified into molecular subtypes based on differential expression of lineage-defining transcription factors. Recent studies have proposed new subtypes that are based on both tumor-intrinsic and -extrinsic factors. SCLC demonstrates substantial intratumoral subtype heterogeneity characterized by highly plastic transcriptional states, indicating that the initially dominant subtype can shift during disease progression and in association with resistance to therapy. Strategies to promote or constrain plasticity and cell fate transitions have nominated novel targets that could prompt the development of more durably effective therapies for patients with SCLC. In this review, we describe the latest advances in SCLC subtype classification and their biological and clinical implications.

Left out in the cold: Moving beyond hormonal therapy for the treatment of immunologically cold prostate cancer with CAR T cell immunotherapies

Prostate cancer is primarily hormone-dependent, and medical treatments have focused on inhibiting androgen biosynthesis or signaling through various approaches. Despite significant advances with the introduction of androgen receptor signalling inhibitors (ARSIs), patients continue to progress to castration-resistant prostate cancer (CRPC), highlighting the need for targeted therapies that extend beyond hormonal blockade. Chimeric Antigen Receptor (CAR) T cells and other engineered immune cells represent a new generation of adoptive cellular therapies. While these therapies have significantly enhanced outcomes for patients with hematological malignancies, ongoing research is exploring the broader use of CAR T therapy in solid tumors, including advanced prostate cancer. In general, CAR T cell therapies are less effective against solid cancers with the immunosuppressive tumor microenvironment hindering T cell infiltration, activation and cytotoxicity following antigen recognition. In addition, inherent tumor heterogeneity exists in patients with advanced prostate cancer that may prevent durable therapeutic responses using single-target agents. These barriers must be overcome to inform clinical trial design and improve treatment efficacy. In this review, we discuss the innovative and rationally designed strategies under investigation to improve the clinical translation of cellular immunotherapy in prostate cancer and maximise therapeutic outcomes for these patients.

Bispecific antibodies: advancing precision oncology

Bispecific antibodies (bsAbs) are engineered molecules designed to target two different epitopes or antigens. The mechanism of action is determined by the bsAb molecular targets and structure (or format), which can be manipulated to create variable and novel functionalities, including linking immune cells with tumor cells, or dual signaling pathway blockade. Several bsAbs have already changed the treatment landscape of hematological malignancies and select solid cancers. However, the mechanisms of resistance to these agents are understudied and the management of toxicities remains challenging. Herein, we review the principles in bsAb engineering, current understanding of mechanisms of action and resistance, data for clinical application, and provide a perspective on ongoing challenges and future developments in this field.

Advances in predictive biomarkers associated with immunotherapy in extensive-stage small cell lung cancer

Small cell lung cancer (SCLC) is a highly malignant and poor-prognosis cancer, with most cases diagnosed at the extensive stage (ES). Amidst a landscape marked by limited progress in treatment modalities for ES-SCLC over the past few decades, the integration of immune checkpoint inhibitors (ICIs) with platinum-based chemotherapy has provided a milestone approach for improving prognosis, emerging as the new standard for initial therapy in ES-SCLC. However, only a minority of SCLC patients can benefit from ICIs, which frequently come with varying degrees of immune-related adverse events (irAEs). Therefore, it is crucial to investigate predictive biomarkers to screen potential beneficiaries of ICIs, mitigate the risk of side effects, and improve treatment precision. This review summarized potential biomarkers for predicting ICI response in ES-SCLC, with a primary focus on markers sourced from tumor tissue or peripheral blood samples. The former mainly included PD-L1 expression, tumor mutational burden (TMB), along with cellular or molecular components related to the tumor microenvironment (TME) and antigen presentation machinery (APM), molecular subtypes of SCLC, and inflammatory gene expression profiles. Circulating biomarkers predominantly comprised circulating tumor DNA (ctDNA), circulating tumor cells (CTCs), cytokines, plasma autoantibodies, inflammation-related parameters, and blood TMB. We synthesized and analyzed the research progress of these potential markers. Notably, investigations into PD-L1 expression and TMB have been the most extensive, exhibiting preliminary predictive efficacy in salvage immunotherapy; however, consistent conclusions have yet to be reached across studies. Additionally, novel predictive markers developed based on TME composition, APM, transcriptomic and genomic features provide promising tools for precision immunotherapy. Circulating biomarkers offer the advantages of convenience, non-invasiveness, and a comprehensive reflection of tumor molecular characteristics. They may serve as alternative options for predicting immunotherapy efficacy in SCLC. However, there is a scarcity of studies, and the significant heterogeneity in research findings warrants attention.

Transcriptomic Differences in Medullary Thyroid Carcinoma According to Grade

Medullary thyroid carcinoma (MTC) is a rare cancer derived from neuroendocrine C-cells of the thyroid. In contrast to other neuroendocrine tumors, a histological grading system was lacking until recently. A novel two-tier grading system based on the presence of high proliferation or necrosis is associated with prognosis. Transcriptomic analysis was conducted on 21 MTCs, including 9 high-grade tumors, with known mutational status, using the NanoString Tumor Signaling 360 Panel. This analysis, covering 760 genes, revealed upregulation of the genes EGLN3, EXO1, UBE2T, UBE2C, FOXM1, CENPA, DLL3, CCNA2, SOX2, KIF23, and CDCA5 in high-grade MTCs. Major pathways differentially expressed between high-grade and low-grade MTCs were DNA damage repair, p53 signaling, cell cycle, apoptosis, and Myc signaling. Validation through qRT-PCR in 30 MTCs demonstrated upregulation of ASCL1, DLL3, and SOX2 in high-grade MTCs, a gene signature akin to small-cell lung carcinoma, molecular subgroup A. Subsequently, DLL3 expression was validated by immunohistochemistry. MTCs with DLL3 overexpression (defined as ≥ 50% of positive tumor cells) were associated with significantly lower disease-free survival (p = 0.041) and overall survival (p = 0.01). Moreover, MTCs with desmoplasia had a significantly increased expression of DLL3. Our data supports the idea that DLL3 should be further explored as a predictor of aggressive disease and poor outcomes in MTC.

Immunophenotypic, genetic, and clinical characterization of adult T-cell leukemia/lymphoma: A single tertiary care center experience in the United States

OBJECTIVES

Adult T-cell leukemia/lymphoma (ATLL) is an aggressive mature T-cell neoplasm caused by human T-cell lymphotropic virus type 1 (HTLV-1). Its most common immunophenotype is CD4+/CD7-/CD25+, although unusual immunophenotypes can occur and may lead to misdiagnosis.

METHODS

The immunophenotypes, cytogenetics, molecular features, clinical presentations, treatment, and prognosis of 131 patients with ATLL were retrospectively studied in a large tertiary medical center in the United States.

RESULTS

All cases showed loss of CD7 expression. While 82.4% of cases demonstrated CD4+, 17.6% exhibited unusual phenotypes, including CD4+/CD8+ (6.9%), CD4-/CD8- (2.3%), CD5- (3.1%), CD2-, and CD3-. The most common cytogenetics abnormalities included polysomy 3 (34.6%), translocation 1 (23.1%), and abnormalities found on chromosome 11 (30.8%) and chromosome 14 (26.9%). The common gene mutations identified by the next-generation sequencing study were TP53 (16.7%), TBL1XR1 (16.7%), EP300 (14.3%), and NOTCH1 (14.3%). TBL1XR1 mutation is associated with genetic instabilities. There was no significant difference between the clinical presentations of these 2 groups.

CONCLUSIONS

Adult T-cell leukemia/lymphoma exhibits versatile immunophenotypic, cytogenetic, and molecular features. Simultaneous involvement of blood, lymph nodes, and other organs, along with hypercalcemia in a patient from an endemic area, necessitates HTLV-1 testing to avoid underdiagnosis of this dismal disease that might need aggressive chemotherapy followed by bone marrow transplant.

The Genetic Analysis and Clinical Therapy in Lung Cancer: Current Advances and Future Directions

Lung cancer, including both non-small cell lung cancer and small cell lung cancer, remains the leading cause of cancer-related mortality worldwide, representing 18% of the total cancer deaths in 2020. Many patients are identified already at an advanced stage with metastatic disease and have a worsening prognosis. Recent advances in the genetic understanding of lung cancer have opened new avenues for personalized treatments and targeted therapies. This review examines the latest discoveries in the genetics of lung cancer, discusses key biomarkers, and analyzes current clinical therapies based on this genetic information. It will conclude with a discussion of future prospects and potential research directions.

Immunotherapy for small cell lung cancer: the current state and future trajectories

Small cell lung cancer (SCLC) constitutes approximately 10% to 15% of all lung cancer diagnoses and represents a pressing global public health challenge due to its high mortality rates. The efficacy of conventional treatments for SCLC is suboptimal, characterized by limited anti-tumoral effects and frequent relapses. In this context, emerging research has pivoted towards immunotherapy combined with chemotherapy, a rapidly advancing field that has shown promise in ameliorating the clinical outcomes of SCLC patients. Through originally developed for non-small cell lung cancer (NSCLC), these therapies have extended new treatment avenues for SCLC. Currently, a nexus of emerging hot-spot treatments has demonstrated significant therapeutic efficacy. Based on the amalgamation of chemotherapy and immunotherapy, and the development of new immunotherapy agents, the treatment of SCLC has seen the hoping future. Progress has been achieved in enhancing the tumor immune microenvironment through the concomitant use of chemotherapy, immunotherapy, and tyrosine kinase inhibitors (TKI), as evinced by emerging clinical trial data. Moreover, a tripartite approach involving immunotherapy, targeted therapy, and chemotherapy appears auspicious for future clinical applications. Overcoming resistance to post-immunotherapy regimens remains an urgent area of exploration. Finally, bispecific antibodies, adoptive cell transfer (ACT), oncolytic virus, monotherapy, including Delta-like ligand 3 (DLL3) and T cell immunoreceptor with Ig and ITIM domains (TIGIT), as well as precision medicine, may present a prospective route towards achieving curative outcomes in SCLC. This review aims to synthesize extant literature and highlight future directions in SCLC treatment, acknowledging the persistent challenges in the field. Furthermore, the continual development of novel therapeutic agents and technologies renders the future of SCLC treatment increasingly optimistic.

DB-1314, a novel DLL3-targeting ADC with DNA topoisomerase I inhibitor, exhibits promising safety profile and therapeutic efficacy in preclinical small cell lung cancer models

BACKGROUND

Delta-like ligand 3 (DLL3) is highly expressed on the cell surface of small cell lung cancer (SCLC), one of the most lethal malignancies, but minimally or not in normal tissues, making it an attractive target for SCLC. However, none of the DLL3-targeting antibody-drug conjugates (ADCs) have been approved for SCLC therapy yet. We developed DB-1314, the new anti-DLL3 ADC composed of a novel humanized anti-DLL3 monoclonal antibody (DB131401) conjugated with eight molecules of P1021 (topoisomerase I inhibitor), and described its preclinical profiles.

METHODS

The binding epitope for DB131401 and Rovalpituzumab was tested by biolayer interferometry. The binding affinity and specificity of DB-1314 to DLL3 and other homologous proteins were respectively measured by surface plasmon resonance and enzyme-linked immunosorbent assay. Internalization, bystander effects, and antibody-dependent cell-mediated cytotoxicity (ADCC) were assessed by respective assay. DLL3 was quantified by antibodies bound per cell assay and immunohistochemistry. In vitro and in vivo growth inhibition studies were evaluated in SCLC cell lines, and cell line/patient-derived xenograft models. The safety profile was measured in cynomolgus monkeys.

RESULTS

DB-1314 induces potent, durable, and dose-dependent antitumor effects in cells in vitro and in cell/patient-derived xenograft models in vivo. The killing activity of DB-1314 mechanically arises from P1021-induced DNA damage, whereby P1021 is delivered and released within tumor cells through DLL3-specific binding and efficient internalization. Bystander effects and ADCC also contribute to the antitumor activity of DB-1314. DB-1314 displays favorable pharmacokinetic and toxicokinetic profiles in rats and cynomolgus monkeys; besides, DB-1314 is well-tolerated at a dose of up to 60 mg/kg in monkeys.

CONCLUSIONS

These results suggest that DB-1314 may be a candidate ADC targeting DLL3 for the treatment of DLL3-positive SCLC, supporting further evaluation in the clinical setting.

Rediscovering immunohistochemistry in lung cancer

Several observations indicate that protein expression analysis by immunohistochemistry (IHC) remains relevant in individuals with non-small-cell lung cancer (NSCLC) when considering targeted therapy, as an early step in diagnosis and for therapy selection. Since the advent of next-generation sequencing (NGS), the role of IHC in testing for NSCLC biomarkers has been forgotten or ignored. We discuss how protein-level investigations maintain a critical role in defining sensitivity to lung cancer therapies in oncogene- and non-oncogene-addicted cases and in patients eligible for immunotherapy, suggesting that IHC testing should be reconsidered in clinical practice. We also argue how a panel of IHC tests should be considered complementary to NGS and other genomic assays. This is relevant to current clinical diagnostic practice but with potential future roles to optimize the selection of patients for innovative therapies. At the same time, strict validation of antibodies, assays, scoring systems, and intra- and interobserver reproducibility is needed.

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.

Imaging with [89Zr]Zr-DFO-SC16.56 anti-DLL3 antibody in patients with high-grade neuroendocrine tumours of the lung and prostate: a phase 1/2, first-in-human trial

BACKGROUND

Delta-like ligand 3 (DLL3) is aberrantly expressed on the surface of small-cell lung cancer (SCLC) and neuroendocrine prostate cancer cells. We assessed the safety and feasibility of the DLL3-targeted imaging tracer [89Zr]Zr-DFO-SC16.56 (composed of the anti-DLL3 antibody SC16.56 conjugated to p-SCN-Bn-deferoxamine [DFO] serving as a chelator for zirconium-89) in patients with neuroendocrine-derived cancer.

METHODS

We conducted an open-label, first-in-human study of immunoPET-CT imaging with [89Zr]Zr-DFO-SC16.56. The study was done at Memorial Sloan Kettering Cancer Center, New York, NY, USA. Patients aged 18 years or older with a histologically verified neuroendocrine-derived malignancy and an Eastern Cooperative Oncology Group performance status of 0-2 were eligible. An initial cohort of patients with SCLC (cohort 1) received 37-74 MBq [89Zr]Zr-DFO-SC16.56 as a single intravenous infusion at a total mass dose of 2·5 mg and had serial PET-CT scans at 1 h, day 1, day 3, and day 7 post-injection. The primary outcomes of phase 1 of the study (cohort 1) were to estimate terminal clearance half-time, determine whole organ time-integrated activity coefficients, and assess the safety of [89Zr]Zr-DFO-SC16.56. An expansion cohort of additional patients (with SCLC, neuroendocrine prostate cancer, atypical carcinoid tumours, and non-small-cell lung cancer; cohort 2) received a single infusion of [89Zr]Zr-DFO-SC16.56 at the same activity and mass dose as in the initial cohort followed by a single PET-CT scan 3-6 days later. Retrospectively collected tumour biopsy samples were assessed for DLL3 by immunohistochemistry. The primary outcome of phase 2 of the study in cohort 2 was to determine the potential association between tumour uptake of the tracer and intratumoural DLL3 protein expression, as determined by immunohistochemistry. This study is ongoing and is registered with ClinicalTrials.gov, NCT04199741.

FINDINGS

Between Feb 11, 2020, and Jan 30, 2023, 12 (67%) men and six (33%) women were enrolled, with a median age of 64 years (range 23-81). Cohort 1 included three patients and cohort 2 included 15 additional patients. Imaging of the three patients with SCLC in cohort 1 showed strong tumour-specific uptake of [89Zr]Zr-DFO-SC16.56 at day 3 and day 7 post-injection. Serum clearance was biphasic with an estimated terminal clearance half-time of 119 h (SD 31). The highest mean absorbed dose was observed in the liver (1·83 mGy/MBq [SD 0·36]), and the mean effective dose was 0·49 mSv/MBq (SD 0·10). In cohort 2, a single immunoPET-CT scan on day 3-6 post-administration could delineate DLL3-avid tumours in 12 (80%) of 15 patients. Tumoural uptake varied between and within patients, and across anatomical sites, with a wide range in maximum standardised uptake value (from 3·3 to 66·7). Tumour uptake by [89Zr]Zr-DFO-SC16.56 was congruent with DLL3 immunohistochemistry in 15 (94%) of 16 patients with evaluable tissue. Two patients with non-avid DLL3 SCLC and neuroendocrine prostate cancer by PET scan showed the lowest DLL3 expression by tumour immunohistochemistry. One (6%) of 18 patients had a grade 1 allergic reaction; no grade 2 or worse adverse events were noted in either cohort.

INTERPRETATION

DLL3 PET-CT imaging of patients with neuroendocrine cancers is safe and feasible. These results show the potential utility of [89Zr]Zr-DFO-SC16.56 for non-invasive in-vivo detection of DLL3-expressing malignancies.

FUNDING

National Institutes of Health, Prostate Cancer Foundation, and Scannell Foundation.

Cancer treatments: Past, present, and future

There is a rich history of cancer treatments which provides a number of important lessons for present and future cancer therapies. We outline this history by looking in the past, reviewing the current landscape of cancer treatments, and by glancing at the potential future cancer therapies.

Antibody-drug conjugates treatment of small cell lung cancer: advances in clinical research

Small cell lung cancer (SCLC) is an extremely aggressive cancer with a relatively low median survival rate after diagnosis. Treatment options such as chemotherapy or combination immunotherapy have shown clinical benefits, but resistance and relapse can occur. Antibody-drug conjugates (ADCs), as a novel class of biopharmaceutical compounds, have broad application prospects in the treatment of SCLC. ADCs consist of monoclonal antibodies that specifically target cancer cells and are attached to cytotoxic drugs, allowing for targeted killing of cancer cells while sparing healthy tissues. Current clinical studies focus on Delta-like protein 3 (DLL3), CD56, Trophoblast cell surface antigen 2 (Trop-2), B7-H3, and SEZ6. Although toxicities exceeding expectations have been observed with Rova-T, drugs targeting TROP-2 (Sacituzumab Govitecan), B7-H3 (DS-7300), and SEZ6 (ABBV-011) have shown exciting clinical benefits. In this review, we collect the latest clinical evidence to describe the therapeutic efficacy and safety of ADCs in SCLC and discuss prospects and challenges.

Tarlatamab: First Approval

Tarlatamab (tarlatamab-dlle: IMDELLTRA™) is a first-in-class, half-life extended bispecific delta-like ligand 3 (DLL3)-directed CD3 T-cell engager being developed by Amgen for the treatment of small cell lung cancer (SCLC) and neuroendocrine prostate cancer. Tarlatamab binds to DLL3 on the surface of tumour cells and CD3 on the surface of cytotoxic T lymphocytes (CTLs), resulting in T-cell activation, release of inflammatory cytokines and CTL-mediated cell death of DLL3-expressing tumour cells. In May 2024, tarlatamab received its first approval in the USA for the treatment of adults with extensive stage SCLC (ES-SCLC) with disease progression on or after platinum-based chemotherapy. Tarlatamab received accelerated approval for this indication based on overall response rate and duration of response in the pivotal phase 2 DeLLphi-301 study, and continued approval may be contingent on the demonstration of clinical benefit in a confirmatory trial(s). Tarlatamab is under regulatory review in Brazil, Canada, Israel and the UK, and clinical studies are underway in multiple countries. This article summarizes the milestones in the development of tarlatamab leading to this first approval for ES-SCLC with disease progression on or after platinum-based chemotherapy.

Facts and Hopes on Cancer Immunotherapy for Small Cell Lung Cancer

Platinum-based chemotherapy plus PD1 axis blockade is the standard of care in the first-line treatment of extensive-stage small cell lung cancer (SCLC). Despite the robust and consistent increase in long-term survival with PD1 axis inhibition, the magnitude of the benefit from immunotherapy seems lower than that for other solid tumors. Several immune evasive mechanisms have been shown to be prominently altered in human SCLC, including T-cell exclusion, downregulation of components of the MHC class I antigen processing and presentation machinery, or upregulation of macrophage inhibitory checkpoints, among others. New immunotherapies aiming to target some of these dominant immune suppressive features are being intensively evaluated preclinically and clinically in SCLC. They include strategies to enhance the efficacy and/or reverse features that promote intrinsic resistance to PD1 axis inhibition (e.g., restoring MHC class I deficiency and targeting DNA damage response) and novel immunomodulatory agents beyond T-cell checkpoint blockers (e.g., T cell-redirecting strategies, antibody-drug conjugates, or macrophage checkpoint blockers). Among them, delta-like ligand 3-targeted bispecific T-cell engagers have shown the most compelling preliminary evidence of clinical efficacy and hold promise as therapies that might contribute to further improve patient outcomes in this disease. In this study, we first provide a brief overview of key tumor microenvironment features of human SCLC. Then, we update the current clinical evidence with immune checkpoint blockade and review other emerging immunotherapy strategies that are gaining increasing attention in SCLC. We finally summarize our future perspective on immunotherapy and precision oncology for this disease.

TREM1/DAP12 based novel multiple chain CAR-T cells targeting DLL3 show robust anti-tumour efficacy for small cell lung cancer

Small cell lung cancer (SCLC), recognized as the most aggressive subtype of lung cancer, presents an extremely poor prognosis. Currently, patients with small cell lung cancer face a significant dearth of effective alternative treatment options once they experience recurrence and progression after first-line therapy. Despite the promising efficacy of immunotherapy, particularly immune checkpoint inhibitors in non-small cell lung cancer (NSCLC) and various other tumours, its impact on significantly enhancing the prognosis of SCLC patients remains elusive. DLL3 has emerged as a compelling target for targeted therapy in SCLC due to its high expression on the membranes of SCLC and other neuroendocrine carcinoma cells, with minimal to no expression in normal cells. Our previous work led to the development of a novel multiple chain chimeric antigen receptor (CAR) leveraging the TREM1 receptor and DAP12, which efficiently activated T cells and conferred potent cell cytotoxicity. In this study, we have developed a DLL3-TREM1/DAP12 CAR-T (DLL3-DT CAR-T) therapy, demonstrating comparable anti-tumour efficacy against SCLC cells in vitro. In murine xenograft and patient-derived xenograft models, DLL3-DT CAR-T cells exhibited a more robust tumour eradication efficiency than second-generation DLL3-BBZ CAR-T cells. Furthermore, we observed elevated memory phenotypes, induced durable responses, and activation under antigen-presenting cells in DLL3-DT CAR-T cells. Collectively, these findings suggest that DLL3-DT CAR-T cells may offer a novel and potentially effective therapeutic strategy for treating DLL3-expressing SCLC and other solid tumours.

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.

Immune checkpoint blockade resistance in lung cancer: emerging mechanisms and therapeutic opportunities

Immune checkpoint blockade (ICB) therapy works by inhibiting suppressive checkpoints that become upregulated after T cell activation, like PD-1/PD-L1 and CTLA-4. While the initial FDA approvals of ICB have revolutionized cancer therapies and fueled a burgeoning immuno-oncology field, more recent clinical development of new agents has been slow. Here, focusing on lung cancer, we review the latest research uncovering tumor cell intrinsic and extrinsic ICB resistance mechanisms as major hurdles to treatment efficacy and clinical progress. These include genomic and non-genomic tumor cell alterations, along with host and microenvironmental factors like the microbiome, metabolite accumulation, and hypoxia. Together, these factors can cooperate to promote immunosuppression and ICB resistance. Opportunities to prevent resistance are constantly evolving in this rapidly expanding field, with the goal of moving toward personalized immunotherapeutic regimens.

Notch signaling pathway in cancer: from mechanistic insights to targeted therapies

Notch signaling, renowned for its role in regulating cell fate, organ development, and tissue homeostasis across metazoans, is highly conserved throughout evolution. The Notch receptor and its ligands are transmembrane proteins containing epidermal growth factor-like repeat sequences, typically necessitating receptor-ligand interaction to initiate classical Notch signaling transduction. Accumulating evidence indicates that the Notch signaling pathway serves as both an oncogenic factor and a tumor suppressor in various cancer types. Dysregulation of this pathway promotes epithelial-mesenchymal transition and angiogenesis in malignancies, closely linked to cancer proliferation, invasion, and metastasis. Furthermore, the Notch signaling pathway contributes to maintaining stem-like properties in cancer cells, thereby enhancing cancer invasiveness. The regulatory role of the Notch signaling pathway in cancer metabolic reprogramming and the tumor microenvironment suggests its pivotal involvement in balancing oncogenic and tumor suppressive effects. Moreover, the Notch signaling pathway is implicated in conferring chemoresistance to tumor cells. Therefore, a comprehensive understanding of these biological processes is crucial for developing innovative therapeutic strategies targeting Notch signaling. This review focuses on the research progress of the Notch signaling pathway in cancers, providing in-depth insights into the potential mechanisms of Notch signaling regulation in the occurrence and progression of cancer. Additionally, the review summarizes pharmaceutical clinical trials targeting Notch signaling for cancer therapy, aiming to offer new insights into therapeutic strategies for human malignancies.

Effects of KEAP1 Silencing on NRF2 and NOTCH Pathways in SCLC Cell Lines

The KEAP1/NRF2 pathway is a master regulator of several redox-sensitive genes implicated in the resistance of tumor cells against therapeutic drugs. The dysfunction of the KEAP1/NRF2 system has been correlated with neoplastic patients' outcomes and responses to conventional therapies. In lung tumors, the growth and the progression of cancer cells may also involve the intersection between the molecular NRF2/KEAP1 axis and other pathways, including NOTCH, with implications for antioxidant protection, survival of cancer cells, and drug resistance to therapies. At present, the data concerning the mechanism of aberrant NRF2/NOTCH crosstalk as well as its genetic and epigenetic basis in SCLC are incomplete. To better clarify this point and elucidate the contribution of NRF2/NOTCH crosstalk deregulation in tumorigenesis of SCLC, we investigated genetic and epigenetic dysfunctions of the KEAP1 gene in a subset of SCLC cell lines. Moreover, we assessed its impact on SCLC cells' response to conventional chemotherapies (etoposide, cisplatin, and their combination) and NOTCH inhibitor treatments using DAPT, a γ-secretase inhibitor (GSI). We demonstrated that the KEAP1/NRF2 axis is epigenetically controlled in SCLC cell lines and that silencing of KEAP1 by siRNA induced the upregulation of NRF2 with a consequent increase in SCLC cells' chemoresistance under cisplatin and etoposide treatment. Moreover, KEAP1 modulation also interfered with NOTCH1, HES1, and DLL3 transcription. Our preliminary data provide new insights about the downstream effects of KEAP1 dysfunction on NRF2 and NOTCH deregulation in this type of tumor and corroborate the hypothesis of a cooperation of these two pathways in the tumorigenesis of SCLC.

DLL3-guided therapies in small-cell lung cancer: from antibody-drug conjugate to precision immunotherapy and radioimmunotherapy

DLL3 acts as an inhibitory ligand that downregulates Notch signaling and is upregulated by ASCL1, a transcription factor prevalent in the small-cell lung cancer (SCLC) subtype SCLC-A. Currently, the therapeutic strategies targeting DLL3 are varied, including antibody-drug conjugates (ADCs), bispecific T-cell engagers (BiTEs), and chimeric antigen receptor (CAR) T-cell therapies. Although rovalpituzumab tesirine (Rova-T) showed promise in a phase II study, it failed to produce favorable results in subsequent phase III trials, leading to the cessation of its development. Conversely, DLL3-targeted BiTEs have garnered significant clinical interest. Tarlatamab, for instance, demonstrated enhanced response rates and progression-free survival compared to the standard of care in a phase II trial; its biologics license application (BLA) is currently under US Food and Drug Administration (FDA) review. Numerous ongoing phase III studies aim to further evaluate tarlatamab's clinical efficacy, alongside the development of novel DLL3-targeted T-cell engagers, both bispecific and trispecific. CAR-T cell therapies targeting DLL3 have recently emerged and are undergoing various preclinical and early-phase clinical studies. Additionally, preclinical studies have shown promising efficacy for DLL3-targeted radiotherapy, which employs β-particle-emitting therapeutic radioisotopes conjugated to DLL3-targeting antibodies. DLL3-targeted therapies hold substantial potential for SCLC management. Future clinical trials will be crucial for comparing treatment outcomes among various approaches and exploring combination therapies to improve patient survival outcomes.

Molecular and Pathologic Characterization of YAP1-Expressing Small Cell Lung Cancer Cell Lines Leads to Reclassification as SMARCA4-Deficient Malignancies

PURPOSE

The classification of small cell lung cancer (SCLC) into distinct molecular subtypes defined by ASCL1, NEUROD1, POU2F3, or YAP1 (SCLC-A, -N, -P, or -Y) expression, paves the way for a personalized treatment approach. However, the existence of a distinct YAP1-expressing SCLC subtype remains controversial.

EXPERIMENTAL DESIGN

To better understand YAP1-expressing SCLC, the mutational landscape of human SCLC cell lines was interrogated to identify pathogenic alterations unique to SCLC-Y. Xenograft tumors, generated from cell lines representing the four SCLC molecular subtypes, were evaluated by a panel of pathologists who routinely diagnose thoracic malignancies. Diagnoses were complemented by transcriptomic analysis of primary tumors and human cell line datasets. Protein expression profiles were validated in patient tumor tissue.

RESULTS

Unexpectedly, pathogenic mutations in SMARCA4 were identified in six of eight SCLC-Y cell lines and correlated with reduced SMARCA4 mRNA and protein expression. Pathologist evaluations revealed that SMARCA4-deficient SCLC-Y tumors exhibited features consistent with thoracic SMARCA4-deficient undifferentiated tumors (SMARCA4-UT). Similarly, the transcriptional profile SMARCA4-mutant SCLC-Y lines more closely resembled primary SMARCA4-UT, or SMARCA4-deficient non-small cell carcinoma, than SCLC. Furthermore, SMARCA4-UT patient samples were associated with a YAP1 transcriptional signature and exhibited strong YAP1 protein expression. Together, we found little evidence to support a diagnosis of SCLC for any of the YAP1-expressing cell lines originally used to define the SCLC-Y subtype.

CONCLUSIONS

SMARCA4-mutant SCLC-Y cell lines exhibit characteristics consistent with SMARCA4-deficient malignancies rather than SCLC. Our findings suggest that, unlike ASCL1, NEUROD1, and POU2F3, YAP1 is not a subtype defining transcription factor in SCLC. See related commentary by Rekhtman, p. 1708.

Myofibrillogenesis Regulator-1 Regulates the Ubiquitin Lysosomal Pathway of Notch3 Intracellular Domain Through E3 Ubiquitin-Protein Ligase Itchy Homolog in the Metastasis of Non-Small Cell Lung Cancer

Myofibrillogenesis regulator-1 (MR-1) is a multifunctional protein involved in the development of various human tumors. The study is the first to report the promoting effect of MR-1 on the development and metastasis of non-small cell lung cancer (NSCLC). MR-1 is upregulated in NSCLC and positively associated with poor prognosis. The overexpression of MR-1 promotes the metastasis of NSCLC cells by stabilizing the expression of Notch3-ICD (NICD3) in the cytoplasm through enrichment analysis, in vitro and in vivo experimental researches. And Notch3 signaling can upregulate many genes related to metastasis. The stabilizing effect of MR-1 on NICD3 is achieved through the mono-ubiquitin lysosomal pathway and the specific E3 ubiquitin ligase is Itchy homolog (ITCH). There is a certain interaction between MR-1 and NICD3. Elevated MR-1 can affect the level of ITCH phosphorylation, reduce its E3 enzyme activity, and thus lead to reduce the ubiquitination and degradation of NICD3. Interference with the interaction between MR-1 and NICD3 can increase the degradation of NICD3 and impair the metastatic ability of NSCLC cells, which is a previously overlooked treatment option in NSCLC. In summary, interference with the interaction between MR-1 and NICD3 in the progression of lung cancer may be a promising therapeutic target.

Drug conjugates for the treatment of lung cancer: from drug discovery to clinical practice

A drug conjugate consists of a cytotoxic drug bound via a linker to a targeted ligand, allowing the targeted delivery of the drug to one or more tumor sites. This approach simultaneously reduces drug toxicity and increases efficacy, with a powerful combination of efficient killing and precise targeting. Antibody‒drug conjugates (ADCs) are the best-known type of drug conjugate, combining the specificity of antibodies with the cytotoxicity of chemotherapeutic drugs to reduce adverse reactions by preferentially targeting the payload to the tumor. The structure of ADCs has also provided inspiration for the development of additional drug conjugates. In recent years, drug conjugates such as ADCs, peptide‒drug conjugates (PDCs) and radionuclide drug conjugates (RDCs) have been approved by the Food and Drug Administration (FDA). The scope and application of drug conjugates have been expanding, including combination therapy and precise drug delivery, and a variety of new conjugation technology concepts have emerged. Additionally, new conjugation technology-based drugs have been developed in industry. In addition to chemotherapy, targeted therapy and immunotherapy, drug conjugate therapy has undergone continuous development and made significant progress in treating lung cancer in recent years, offering a promising strategy for the treatment of this disease. In this review, we discuss recent advances in the use of drug conjugates for lung cancer treatment, including structure-based drug design, mechanisms of action, clinical trials, and side effects. Furthermore, challenges, potential approaches and future prospects are presented.

Considerations for selecting second-line treatment in patients with progressive small cell lung cancer and the use of Lurbinectedin in this setting

Small cell lung cancer (SCLC) is characterized by high initial responses to platinum-based chemotherapy plus immune checkpoint inhibitors; however, most patients quickly relapse and require subsequent treatment. Second-line treatment options in SCLC remain limited, and treatment algorithms are not completely consistent across the available guidelines in this setting. This review highlights key considerations regarding selection of second-line treatment for patients with relapsed SCLC. In particular, the role of lurbinectedin, which was first approved in 2020, representing the first significant addition to treatment algorithms in this setting for decades, is summarized. Future directions, including the identification of SCLC subtypes and the need for predictive biomarkers to guide patient selection and targeted therapy, are also discussed.

Current challenges and practical aspects of molecular pathology for non-small cell lung cancers

The continuing evolution of treatment options in thoracic oncology requires the pathologist to regularly update diagnostic algorithms for management of tumor samples. It is essential to decide on the best way to use tissue biopsies, cytological samples, as well as liquid biopsies to identify the different mandatory predictive biomarkers of lung cancers in a short turnaround time. However, biological resources and laboratory member workforce are limited and may be not sufficient for the increased complexity of molecular pathological analyses and for complementary translational research development. In this context, the surgical pathologist is the only one who makes the decisions whether or not to send specimens to immunohistochemical and molecular pathology platforms. Moreover, the pathologist can rapidly contact the oncologist to obtain a new tissue biopsy and/or a liquid biopsy if he/she considers that the biological material is not sufficient in quantity or quality for assessment of predictive biomarkers. Inadequate control of algorithms and sampling workflow may lead to false negative, inconclusive, and incomplete findings, resulting in inappropriate choice of therapeutic strategy and potentially poor outcome for patients. International guidelines for lung cancer treatment are based on the results of the expression of different proteins and on genomic alterations. These guidelines have been established taking into consideration the best practices to be set up in clinical and molecular pathology laboratories. This review addresses the current predictive biomarkers and algorithms for use in thoracic oncology molecular pathology as well as the central role of the pathologist, notably in the molecular tumor board and her/his participation in the treatment decision-making. The perspectives in this setting will be discussed.

First-in-human imaging with [89Zr]Zr-DFO-SC16.56 anti-DLL3 antibody in patients with high-grade neuroendocrine tumors of the lung and prostate

Background

Delta-like ligand 3 (DLL3) is aberrantly expressed on the cell surface in many neuroendocrine cancers including small cell lung cancer (SCLC) and neuroendocrine prostate cancer (NEPC). Several therapeutic agents targeting DLL3 are in active clinical development. Molecular imaging of DLL3 would enable non-invasive diagnostic assessment to inform the use of DLL3-targeting therapeutics or to assess disease treatment response.

Methods

We conducted a first-in-human immuno-positron emission tomography (immunoPET) imaging study of [89Zr]Zr-DFO-SC16.56, composed of the anti-DLL3 antibody SC16.56 conjugated to desferrioxamine (DFO) and the positron-emitting radionuclide zirconium-89, in 18 patients with neuroendocrine cancers. An initial cohort of three patients received 1-2 mCi of [89Zr]Zr-DFO-SC16.56 at a total mass dose of 2·5 mg and underwent serial PET and computed tomography (CT) imaging over the course of one week. Radiotracer clearance, tumor uptake, and radiation dosimetry were estimated. An expansion cohort of 15 additional patients were imaged using the initial activity and mass dose. Retrospectively collected tumor biopsies were assessed for DLL3 by immunohistochemistry (IHC) (n = 16).

Findings

Imaging of the initial 3 SCLC patients demonstrated strong tumor-specific uptake of [89Zr]Zr-DFO-SC16.56, with similar tumor: background ratios at days 3, 4, and 7 post-injection. Serum clearance was bi-phasic with an estimated terminal clearance half-time of 119 h. The sites of highest background tracer uptake were blood pool and liver. The normal tissue receiving the highest radiation dose was liver; 1·8 mGy/MBq, and the effective dose was 0.49 mSv/MBq. Tumoral uptake varied both between and within patients, and across anatomic sites, with a wide range in SUVmax (from 3·3 to 66·7). Tumor uptake by [89Zr]Zr-DFO-SC16.56 was associated with protein expression in all cases. Two non-avid DLL3 NEPC cases by PET scanning demonstrated the lowest DLL3 expression by tumor immunohistochemistry. Only one patient had a grade 1 allergic reaction, while no grade ≥2 adverse events noted.

Interpretation

DLL3 PET imaging of patients with neuroendocrine cancers is safe and feasible. These results demonstrate the potential utility of [89Zr]Zr-DFO-SC16.56 for non-invasive in vivo detection of DLL3-expressing malignancies.

Funding

Supported by NIH R01CA213448 (JTP), R35 CA263816 (CMR), U24 CA213274 (CMR), R35 CA232130 (JSL), and a Prostate Cancer Foundation TACTICAL Award (JSL), Scannell foundation. The Radiochemistry and Molecular Imaging Probes Core Facility is supported by NIH P30 CA08748.

Clinical and morphological features of large-cell neuroendocrine carcinomas and small-cell lung carcinomas expressing the DLL3 and ASCL1 oncoproteins

Intratumoral similarities and differences between large-cell neuroendocrine carcinomas (LCNECs) and small-cell lung carcinomas (SCLCs) are determined partially by the Notch signaling pathway, which controls the switch from neuroendocrine to slight/non-neuroendocrine cell fate. LCNECs are divided into two subgroups according to genomic alterations: type I LCNECs exhibit a neuroendocrine profile characterized by achaete-scute homolog 1 (ASCL1)high/delta-like protein 3 (DLL3)high/NOTCHlow and type II LCNECs show the pattern ASCL1low/DLL3low/NOTCHhigh. Here, we used immunohistochemistry, transmission electron microscopy, and digital analysis to examine the role of the Notch ligand DLL3 as an immunomarker of the neuroendocrine state and ASCL1 as a regulator of cell-cell interactions in SCLCs and LCNECs. High DLL3 and ASCL1 expression was associated with atypical submicroscopic characteristics involving nuclear size, chromatin arrangement, Golgi apparatus, and endoplasmic reticulum, and was characteristic of type I LCNECs with similarity to SCLCs, whereas low DLL3 and ASCL1 expression was found in both SCLCs and type II LCNECs. In patients diagnosed at an early stage who did not have metastasis and who underwent chemotherapy, DLL3high and ASCL1high SCLCs and type I LCNECs were associated with a better prognosis and a lower risk of death. The present findings suggested that DLL3/ASCL1 are potential therapeutic targets and prognostic indicators in patients with SCLCs or LCNECs.