Efficacy and Safety of Rovalpituzumab Tesirine Compared With Topotecan as Second-Line Therapy in DLL3-High SCLC: Results From the Phase 3 TAHOE Study

Challenges of small cell lung cancer heterogeneity and phenotypic plasticity

Small cell lung cancer (SCLC) is an aggressive neuroendocrine malignancy with ~7% 5-year overall survival reflecting early metastasis and rapid acquired chemoresistance. Immunotherapy briefly extends overall survival in ~15% cases, yet predictive biomarkers are lacking. Targeted therapies are beginning to show promise, with a recently approved delta-like ligand 3 (DLL3)-targeted therapy impacting the treatment landscape. The increased availability of patient-faithful models, accumulating human tumour biobanks and numerous comprehensive molecular profiling studies have collectively facilitated the mapping and understanding of substantial intertumoural and intratumoural heterogeneity. Beyond the almost ubiquitous loss of wild-type p53 and RB1, SCLC is characterized by heterogeneously mis-regulated expression of MYC family members, yes-associated protein 1 (YAP1), NOTCH pathway signalling, anti-apoptotic BCL2 and epigenetic regulators. Molecular subtypes are based on the neurogenic transcription factors achaete-scute homologue 1 (ASCL1) and neurogenic differentiation factor 1 (NEUROD1), the rarer non-neuroendocrine transcription factor POU class 2 homeobox 3 (POU2F3), and immune- and inflammation-related signatures. Furthermore, SCLC shows phenotypic plasticity, including neuroendocrine-to-non-neuroendocrine transition driven by NOTCH signalling, which is associated with disease progression, chemoresistance and immune modulation and, in mouse models, with metastasis. Although these features pose substantial challenges, understanding the molecular vulnerabilities of transcription factor subtypes, the functional relevance of plasticity and cell cooperation offer opportunities for personalized therapies informed by liquid and tissue biomarkers.

The Era of Precision Medicine: Advancing Treatment Paradigms for Small Cell Lung Cancer

Small cell lung cancer (SCLC) remains a challenge prognostically. A clinically silent early stage and predilection for early metastasis leads to over half of patients presenting with metastatic disease at the time of diagnosis. Akin to many other cancers, once SCLC metastasizes, current therapies begin to lose their effectiveness. The future of SCLC rests in innovative treatments aimed at improving patient outcomes. Chemotherapy and radiation remain the backbone treatment for SCLC. Most patients diagnosed with SCLC begin treatment with combination chemotherapy consisting of a platinum analog and topoisomerase inhibitor with or without concurrent radiation. Disease progression or recurrence warrants new treatment approaches. New chemotherapy combinations and advances in radiation precision offer patients novel approaches using the same backbone of treatment used in many other cancers. The introduction of newer therapeutic approaches, such as immune checkpoint inhibitors, small molecule targeted therapies, bispecific antibodies, and antibody-drug conjugates offer a bright future for patients with SCLC who fail first-line therapy. This review will focus on advancing treatment paradigms for SCLC in the era of precision medicine. Such a study might be helpful for pulmonologists and oncologists to manage precisely patients with SCLC.

Immune checkpoint inhibitor (ICI) therapy in central nervous system cancers: State-of-the-art and future outlook

Invasive central nervous system (CNS) cancers are an area where the development of breakthrough therapies is urgently needed. For instance, conditions such as glioblastoma multiforme (GBM) are associated with poor clinical prognosis, with the majority of trials offering no improvement to marginally enhanced survival. Unleashing the potential of targeting the immune system in CNS cancers has gained attention in recent years. Inhibition of immune checkpoints such as CTLA-4, PD-1/PD-L1, TIM-3, and LAG-3 has been attempted in recent trials. While potentially offering a notable edge over other immunotherapies, multi-organ adverse events have been found with the administration of immune checkpoint inhibitors (ICIs). The present review captures the state-of-the-art evidence on ICI treatments in different CNS cancers. Also, we discuss the value of combinational therapies involving ICIs as well as next-generation therapeutics such as bispecific antibodies targeting PD-1/LAG-3/TIM-3 and CRISPR-Cas9-edited PD-1-knock-out checkpoint-resistant CAR T-cells.

Cancer-nervous system crosstalk: from biological mechanism to therapeutic opportunities

A growing body of research suggests a bidirectional interaction between cancer and the nervous system. Neural cells exert their effects on tumors by secreting neurotransmitters and cell adhesion molecules, which interact with specific receptors on tumor cells to modulate their behavior. Conversely, tumor-secreted factors, particularly including inflammatory factors, can alter neural activity and increase neuronal excitability, potentially contributing to neurological manifestations such as epilepsy. The immune system also serves as a crucial intermediary in the indirect communication between cancer and the nervous system. These insights have opened promising avenues for novel therapeutic strategies targeting both tumors and their associated neurological complications. In this review, we have synthesized the key biological mechanisms underlying cancer-nervous system interactions that have emerged over the past decade. We outline the molecular and cellular pathways mediating this cross-talk and explore the clinical implications of targeting the nervous system to suppress tumor growth and metastasis, mitigate neurological complications arising from cancer progression, and modulate the immune response through neural regulation in the context of cancer therapy.

Efficacy of second line and subsequent treatments of small cell lung cancer with and without immune checkpoint inhibitor combination therapy

BACKGROUND

Immune checkpoint inhibitors (ICIs) combined with platinum-doublet chemotherapy (ICI-chemo) have become the standard of care for extensive-stage small cell lung cancer (ES-SCLC). However, the effect of ICI-chemo on the efficacy of subsequent chemotherapy remains unknown. This study aimed to investigate the efficacy of second and subsequent treatments of SCLC with and without ICI combination therapy.

METHODS

We performed an analysis of patients with ES-SCLC between January 2015 and June 2023. The ICI-chemo groups were defined as patients who received ICI-chemo as first-line therapy between September 2019 and June 2023, after ICI-chemo was reimbursed in Japan. The non-ICI-chemo groups were defined as patients who received platinum-doublet therapy between January 2015 and August 2019 and were considered eligible for ICI-chemo.

RESULTS

In total, 224 patients were included (91 and 133 patients who received ICI-chemo and non-ICI-chemo, respectively). There were no significant differences in patient characteristics between the groups. There was no significant difference in progression-free survival (PFS) and overall survival (OS) for first-line treatment between the two groups. The median PFS and OS periods for second-line treatment were 3.9 and 3.9 months and 10.3 and 10.7 months in the ICI-chemo and non-ICI-chemo groups, respectively, without significant difference. Most patients in both groups received amrubicin as the second-line treatment. Moreover, the PFS and OS periods for third-line treatment were not significantly different between the ICI-chemo and non-ICI-chemo groups.

CONCLUSIONS

In ES-SCLC, there is no significant additive effect on PFS and OS of second- and subsequent line treatments following ICI-chemo at first-line treatment.

Unmet Needs in Maintenance Therapy for Extensive Stage Small Cell Lung Cancer

Small cell lung cancer (SCLC) is a highly aggressive malignancy and an exceptionally lethal disease; most patients present with extensive stage (ES) disease at diagnosis. Very little had changed in the treatment of ES-SCLC for decades until immune checkpoint inhibitor (ICI) therapy combined with chemotherapy followed by ICI maintenance monotherapy was added to standard treatment paradigms in 2019. Despite this important advance, high rates of relapse are still observed in patients with ES-SCLC and long-term survival rates remain low, with approximately 40% of patients proceeding to receive second-line treatment. There is an urgent need for novel treatment strategies to improve patient outcomes. In this review, we describe the rationale for maintenance therapy approaches in ES-SCLC and summarize the existing data on chemotherapy, ICIs, and other agents in the first-line maintenance setting. Predictive biomarkers, SCLC subtypes, and new therapeutics in development are discussed including lurbinectedin, antibody-drug conjugates, and T-cell engager molecules.

Safety and efficacy outcomes of delta‑like ligand 3 inhibitors for the treatment of solid tumors: A systematic review and single‑arm meta‑analysis

The aim of the present study was to evaluate the clinical curative effects and toxicity of existing delta-like ligand 3 (DLL3) inhibitors in advanced solid tumors with high DLL3 expression. A systematic search across major databases was performed, adhering to the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines, and included clinical trials that assessed the efficacy and safety of DLL3 inhibitors in treating solid tumors. To be included, studies had to be randomized controlled trials (RCTs), quasi-RCTs, non-randomized comparative studies, single-arm trials and trials in which DLL3 inhibitors were used in both arms. The results of 21 trials, involving a total of 2,452 patients, which evaluated the efficacy of DLL3 inhibitors in treating solid tumors, were analyzed. The median overall survival was 6.54 months and the median progression-free survival (PFS) was 3.54 months. Combination immunotherapy demonstrated a longer PFS of 4.2 months compared with monotherapy, which had a PFS of 3.36 months. The disease control rate and objective response rate were 57 and 21%, respectively, with notable heterogeneity observed across studies. Adverse events were common, affecting 93% of patients, and included cytokine release syndrome (49%), thrombocytopenia (23%) and peripheral edema (28%), with variations depending on the specific inhibitor used. To conclude, DLL3 inhibitors hold promise for patients with elevated DLL3 expression in solid tumors; however, their efficacy and safety exhibit considerable variability, necessitating large-scale, phase III clinical trials to validate and refine therapeutic approaches. The present study was registered with PROSPERO (registration no. CRD42024561815).

An organoid library unveils subtype-specific IGF-1 dependency via a YAP-AP1 axis in human small cell lung cancer

Small cell lung cancer (SCLC) is a devastating disease with limited therapeutic advancements. Although SCLC has recently been classified into four molecular subtypes, subtype-specific therapies are still lacking. Here, we established 40 patient-derived SCLC organoid lines with predominant TP53 and RB1 alterations and rare targetable genetic lesions. Transcriptome profiling divided the SCLC organoids into neuroendocrine (NE)-type SCLC and non-NE-type SCLC, with the latter characterized by YAP1 or POU2F3 expression. NE-type SCLC organoids grew independent of alveolar niche factors, whereas non-NE-type SCLC organoids relied on insulin-like growth factor (IGF)-1-driven YAP1 and AP1 activation. Therapeutic targeting of IGF-1, YAP1 and AP1 effectively suppressed the growth of non-NE-type organoids. Co-knockout of TP53 and RB1 in human alveolar cells altered their lineage toward the airway epithelium-like fate and conferred IGF-1 dependency, validating the subtype-phenotype connection. Our SCLC organoid library represents a valuable resource for developing biology-based therapies and has the potential to reshape the drug discovery landscape.

Targeting DLL3: Innovative Strategies for Tumor Treatment

Delta-like 3 (DLL3) is an oncogenic protein aberrantly expressed in several tumors, particularly in small-cell lung cancer. DLL3-targeted therapies have recently made significant progress, demonstrating promising preclinical and clinical efficacy. This review aims to explore the mechanisms, challenges, and future opportunities associated with therapies targeting DLL3 for cancer treatment. The biological characteristics of DLL3 and its role in the Notch signaling pathway are introduced first, delving into the role of DLL3 in tumorigenesis and cancer progression. Next, current therapeutic approaches targeting DLL3 are described, including antibody-drug conjugates, T cell engagers, chimeric antigen receptor T cells, and radiopharmaceutical therapy, highlighting their effectiveness and safety in clinical trials. Despite the promising prospects, difficulties remain in the use of DLL3 as a therapeutic target due to tumor heterogeneity, the development of resistance, potential adverse effects, and barriers to patient stratification. Therefore, the potential of combination therapies, the use of innovative drug delivery systems, and ongoing clinical trial advancements are also discussed. Finally, the potential of DLL3-targeted therapies is summarized, highlighting the importance of multidisciplinary research to guide the clinical application and optimization of this emerging treatment strategy. These approaches might provide new therapeutic options, potentially starting a new era in cancer treatment.

Targeting Lung Cancer with Precision: The ADC Therapeutic Revolution

PURPOSE OF REVIEW

This review explores the evolving role of antibody-drug conjugates (ADCs) in lung cancer treatment, with a focus on their application in non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). It highlights advancements in ADC design, mechanisms of action, and key outcomes from recent clinical trials.

RECENT FINDINGS

ADCs have introduced a new level of precision in oncology by targeting tumor-specific antigens such as HER2, HER3, and TROP-2. Recent clinical trials of agents like trastuzumab deruxtecan, datopotamab deruxtecan, and sacituzumab govitecan have demonstrated meaningful objective response rates and manageable toxicity, offering hope for patients with advanced NSCLC and SCLC. ADCs are transforming the treatment landscape for lung cancer, offering a blend of targeted delivery and potent therapeutic effects. With ongoing efforts to improve safety, efficacy, and antigen targeting, ADCs have the potential to become a cornerstone of lung cancer therapy and pave the way for innovative multimodal approaches in the future.

Emerging Therapeutic Targets of Neuroendocrine Prostate Cancer

PURPOSE OF REVIEW

Treatment-emergent neuroendocrine prostate cancer (NEPC) is aggressive and lethal. As androgen receptor signaling inhibitors (ARSIs) are increasingly used in earlier disease settings, treatment-emergent NEPC becomes more prevalent, and effective therapies are urgently needed. The purpose of this review was to summarize recent progress on emerging therapeutic targets of NEPC.

RECENT FINDINGS

A multitude of therapeutic targets have emerged in NEPC over recent years. These targets may represent drivers of treatment-emergent lineage plasticity or simply be overexpressed on the surface of NEPC cells. Multiple modalities have been employed to drug these targets, with promising preclinical and clinical results. Treatment-emergent NEPC represents a distinct and clinically significant subset of castration-resistant prostate cancer (CRPC). Emerging therapeutic approaches have demonstrated encouraging efficacy and safety profiles, offering the potential to improve patient outcomes.

Current and future therapies for small cell lung carcinoma

Small cell lung cancer (SCLC) is an aggressive malignancy characterized by rapid proliferation and high metastatic potential. It is characterized by universal inactivation of and RB1, overexpression of the MYC family and dysregulation of multiple oncogenic signaling pathways. Among different patients, SCLCs are similar at the genetic level but exhibit significant heterogeneity at the molecular level. The classification of SCLC has evolved from a simple neuroendocrine (NE)/non-neuroendocrine (non-NE) classification system to a transcription factor-based molecular subtype system; lineage plasticity adds further complexity and poses challenges for therapeutic development. While SCLC is initially sensitive to platinum-based chemotherapy, resistance develops rapidly, leading to a dismal prognosis. Various antibodies, including PD-1/PD-L1 inhibitors and antibody‒drug conjugates, have been introduced into clinical practice or are being evaluated in clinical trials. However, their therapeutic benefits for SCLC patients remain limited. This review summarizes SCLC carcinogenic mechanisms, tumor heterogeneity, and the immune microenvironment of SCLC, with a focus on recent advances in metastasis and resistance mechanisms. Additionally, the corresponding clinical progress in tackling these challenges is discussed.

The Era of Antibody Drug Conjugates in Lung Cancer: Trick or Threat?

Antibody drug conjugates (ADCs) are a novel class of therapeutics that structurally are composed by an antibody directed to a tumor epitope connected via a linker to a cytotoxic payload, and that have shown significant antitumor activity across a range of malignancies including lung cancer. In this article we review the pharmacology and design of ADCs, as well as we describe the results of different studies evaluating ADCs in lung cancer directed to several targets including HER2, HER3, TROP2, MET, CEACAM5 and DLL3.

Advances in adoptive cell therapies in small cell lung cancer

Small cell lung cancer (SCLC) is an aggressive tumor characterized by early metastasis and resistance to treatment, making it a prime target for therapeutic investigation. The current standard of care for frontline treatment involves a combination of chemotherapeutic agents and immune checkpoint inhibitors (ICIs), though durability of response remains limited. The genetic heterogeneity of SCLC also complicates the development of new therapeutic options. Adoptive cell therapies show promise by targeting specific mutations in order to increase efficacy and minimize toxicity. There has been significant investigation in three therapeutic classes for application towards SCLC: antibody drug conjugates (ADCs), bispecific T-cell engagers (BiTEs), and chimeric antigen receptor (CAR)-T cell therapies. This review summarizes the recent advances and challenges in the development of adoptive cell therapies. Genetic targets such as delta-like ligand 3 (DLL3), trophoblast cell surface antigen 2 (Trop2), B7-H3 (CD276), gangliosides disialoganglioside GD2 (GD2) and ganglioside GM2 (GM2) have been found to be expressed in SCLC, which makes them prime targets for therapy development. While investigated therapies such as rovalpituzumab tesirine (Rova-T) have failed, several insights from these trials have led to the development of compelling new agents such as sacituzumab govitecan (SG), ifinatamab deruxtecan (I-DXd), tarlatamab, and DLL3-targeted CAR-T cells. Advancing development of molecular testing and improving targeted approaches remain integral to pushing forward the progress of adoptive cell therapies in SCLC.

Current and future perspectives in extensive-stage small-cell lung cancer

Small-cell lung cancer (SCLC) is a highly aggressive and rapidly proliferative malignancy that has historically had limited therapeutic advancements. Recent advancements in the understanding of SCLC have led to attempts at subtyping the disease based on transcription factor characteristics, offering new insights into its biology and potential therapeutic targets. In addition, significant progress has been made in developing treatment regimens, providing new hope for improved patient outcomes. The introduction of immune checkpoint inhibitors, such as atezolizumab and durvalumab, in combination with traditional chemotherapy, has marked a significant advancement, demonstrating improved overall survival and progression-free survival compared to chemotherapy alone. Despite these advancements, the prognosis for extensive-stage SCLC (ES-SCLC), the more advanced form of SCLC, remains poor, highlighting the critical need for ongoing research and the development of novel therapeutic strategies. New treatment modalities, such as lurbinectedin and anti-Delta-like Canonical Notch Ligand 3 antibodies, are now included in the treatment options for refractory SCLC, and many more treatment strategies involving combination therapies are being studied. Advances in molecular profiling and the identification of biomarkers are aiding in the development of personalized treatment approaches. This review focuses on these recent advancements and emerging strategies in the treatment of ES-SCLC.

[New perspectives in the management of small cell bronchial cancer]

Small cell lung cancer (SCLC) remains one of the most aggressive cancers, with an overall survival of approximately one year for patients with extensive stage SCLC, and we still have very few effective therapies, especially after the first line of treatment. A better understanding of SCLC and their mechanisms, especially molecular mechanisms, has led to the exploration of new therapeutic strategies. For example, transcriptomic analyses have identified 4 subtypes of CBPC, which could be predictive of response to treatments. Immune checkpoint inhibitors have shown limited benefit in extensive stage SCLC, but appear to have a clear benefit for limited stage SCLC, in association with radio-chemotherapy. Anti- PARP molecules, involved in DNA repair and aberrantly expressed in CBPC, have been studied. New molecules have been developed, to bypass antigen presentation, which is defective in SCLC; such as bispecific T-cell engager molecules, that binds to SCLC cells and patient's cytotoxic T-cell, leading to T-cell activation and tumor lysis. These molecules target tumor cell's surface proteins, such as delta-like ligand 3 (DLL3), aberrantly expressed on the surface of most SCLC cells. Tarlamab, a DLL3-targeted immune therapy, has shown very promising durable responses in patients with previously treated SCLC. These new molecules lead to new side effects we will have to manage, such as the Cytokine Relargage Syndrome. Other molecules, targeting DLL3 or other pathways are still ungoing clinical evaluation, we should see further advances in the treatment of SCLC over the coming years.

Small cell lung cancer unveiled: Exploring the untapped resource of circulating tumor cells-derived organoids

Small cell lung cancer (SCLC) remains a challenge in oncology due to its aggressive behavior and dismal prognosis. Despite advances in treatments, novel strategies are urgently needed. Enter liquid biopsy-a game-changer in SCLC management. This revolutionary non-invasive approach allows for the analysis of circulating tumor cells (CTCs), offering insights into tumor behavior and treatment responses. Our review focuses on a groundbreaking frontier: harnessing CTCs to create three-dimensional (3D) organoid models. These models, derived from CTCs that break away from the primary tumor or metastatic locations, hold immense potential for revolutionizing cancer research, especially in SCLC. We explore the essential conditions for successfully establishing CTC-derived organoids-a transformative approach with profound implications for personalized medicine. Our evaluation spans diverse isolation techniques, shedding light on their advantages and limitations. Furthermore, we uncover the critical factors governing the cultivation of 3D organoids from CTCs, meticulously mimicking the tumor microenvironment. This review comprehensively elucidates the molecular characterization of these organoids, showcasing their potential in identifying treatment targets and predicting responses. In essence, our review amalgamates cutting-edge methodologies for isolating CTCs, establishing transformative CTC-derived organoids, and characterizing their molecular landscape. This represents a promising frontier for advancing personalized medicine in the complex realm of SCLC management and holds significant implications for translational research.

Deciphering Complexity: The Molecular Landscape of Castration-Resistant Prostate Cancer

Despite improvements in diagnosis and treatment approaches, prostate cancer (PC) remains a leading cause of cancer-related death in men. PC progresses through various stages, mostly driven by androgen receptor signaling. However, after androgen deprivation therapies, in a significant portion of patients, several different molecular mechanisms contribute to the development of castration resistance. Delving deeply into the molecular landscape of castration-resistant PC, grasping the selective pressures exerted by therapies, and understanding the drivers of lineage plasticity is pivotal to prevent progression. Targeting genetic and epigenetic alterations that drive this transition will guide clinical management strategies and possibly prevent and/or treat lethal disease.

Deep analysis of the trials and major challenges in the first-line treatment for patients with extensive-stage small cell lung cancer

The median overall survival (OS) is approximately 10 months when chemotherapy alone is the first-line treatment for extensive-stage small cell lung cancer (ES-SCLC). The approval of the two PD-L1 inhibitors, atezolizumab and durvalumab, marked the beginning of the immunotherapy era for ES-SCLC. Serplulimab, as the first PD-1 inhibitor to achieve success in the first-line treatment of ES-SCLC, has not only demonstrated significant improvements in patient survival outcomes but also ushered in a new era for PD-1 inhibitors in the treatment of ES-SCLC. Recently, antiangiogenic agents with chemo-immunotherapy have achieved breakthroughs in first-line ES-SCLC treatment. Improving the clinical benefits of individualized treatment for patients with ES-SCLC remains challenging. Challenges include identifying biomarkers for targeted therapy, exploring new treatments, developing new medicines, and classifying SCLC molecular subtypes. This review provides an in-depth analysis of research on first-line ES-SCLC treatment. Additionally, it discusses advances in ES-SCLC treatment.

Beyond first-line therapy: efficacy and safety outcomes of continuing immunotherapy in extensive stage small cell lung cancer after PD-L1 inhibitor progression

OBJECTIVE

To evaluate the efficacy and safety of the continuing immunotherapy as subsequent therapy in extensive-stage small cell lung cancer (ES-SCLC) patients who have progressed after initial immunotherapy.

METHODS

A retrospective analysis was conducted on patients with ES-SCLC who experienced disease progression after receiving programmed cell death ligand 1 (PD-L1) inhibitors combined with standard chemotherapy as first-line treatment at three sites in China. Patients were divided into two groups according to whether to continue second-line immunotherapy.

RESULTS

In a cohort of 150 ES-SCLC patients evaluated post-progression following first-line PD-L1 inhibitors, second-line treatment regimens varied: 86 patients received immunotherapy beyond progression (IBP) and 64 did not proceed to second-line immunotherapy (non-IBP). IBP significantly increased both disease control rates (DCR, 68.6% vs. 32.8%, p<0.001) and overall response rate (ORR, 33.7% vs. 15.6%, p=0.012) and extended median progression-free survival (PFS, 4.1 vs. 2.4 months, HR=0.46, p<0.001) when compared with non-IBP group. The median overall survival (OS) in the IBP group was also longer than that in the non-IBP group (11.2 months vs. 9.0 months, HR=0.68, 95%CI 0.47-0.98, p=0.042). Subgroup analyses revealed a significant survival advantage with IBP treatment in patients presenting with baseline liver metastases, less than three metastatic organs, and those who were nonsmokers.

CONCLUSIONS

In patients with ES-SCLC who received first-line PD-L1 inhibitors, continuing IBP extended second-line survival without increasing adverse events (AEs). A more pronounced OS benefit with IBP was noted within specific patient subgroups.

Recent Advances in the Clinical Translation of Small-Cell Lung Cancer Therapeutics

Small-cell lung cancer (SCLC) is a recalcitrant form of cancer, representing 15% of lung cancer cases globally. SCLC is classified within the range of neuroendocrine pulmonary neoplasms, exhibiting shared morphologic, ultrastructural, immunohistochemical, and molecular genomic features. It is marked by rapid proliferation, a propensity for early metastasis, and an overall poor prognosis. The current conventional therapies involve platinum-etoposide-based chemotherapy in combination with immunotherapy. Nonetheless, the rapid emergence of therapeutic resistance continues to pose substantial difficulties. The genomic profiling of SCLC uncovers significant chromosomal rearrangements along with a considerable mutation burden, typically involving the functional inactivation of the tumor suppressor genes TP53 and RB1. Identifying biomarkers and evaluating new treatments is crucial for enhancing outcomes in patients with SCLC. Targeted therapies such as topoisomerase inhibitors, DLL3 inhibitors, HDAC inhibitors, PARP inhibitors, Chk1 inhibitors, etc., have introduced new therapeutic options for future applications. In this current review, we will attempt to outline the key molecular pathways that play a role in the development and progression of SCLC, together with a comprehensive overview of the most recent advancements in the development of novel targeted treatment strategies, as well as some ongoing clinical trials against SCLC, with the goal of improving patient outcomes.

Assessment of targets of antibody drug conjugates in SCLC

Antibody-drug conjugate (ADC) therapy has transformed treatment for several solid tumors, including small cell lung cancer (SCLC). However, significant challenges remain, including systemic toxicity, acquired resistance, and the lack of reliable biomarkers for patient selection. To enhance the effectiveness of ADC therapies in SCLC, we focused on target selection in this study by investigating the expression of ADC targets - SEZ6, DLL3, CD276, and TACSTD2 - in cell lines and patient samples. SEZ6 expression was significantly elevated in various SCLC transcriptional subtypes, particularly ASCL1, and exhibited gender-specific differences, being lower in women. DLL3 was primarily observed in the ASCL1 subtype, while CD276 showed high expression in non-neuroendocrine subtypes. TACSTD2 levels were generally low and attenuated in lymph nodes and brain metastases compared to primary tumors. Our findings underscore the importance of understanding target expression patterns to optimize ADC therapy and advance precision medicine in SCLC treatment.

Phase 2 Open-Label Study of Sacituzumab Govitecan as Second-Line Therapy in Patients With Extensive-Stage SCLC: Results From TROPiCS-03

INTRODUCTION

The phase 2 TROPiCS-03 study evaluated the efficacy/safety of sacituzumab govitecan (SG) as second-line treatment in patients with previously treated extensive-stage SCLC (ES-SCLC).

METHODS

TROPiCS-03 (NCT03964727) is a multicohort, open-label, phase 2 basket study of solid tumors, including ES-SCLC. Adults with ES-SCLC that progressed after one previous line of platinum-based chemotherapy and anti-programmed death-(ligand) 1 (PD-[L]1) therapy received SG 10 mg/kg on days 1 and 8 of a 21-day cycle. The primary end point was the investigator-assessed objective response rate (ORR) according to Response Evaluation Criteria in Solid Tumors version 1.1. Key secondary end points included investigator-assessed duration of response (DOR) and progression-free survival (PFS); blinded independent central review-assessed ORR, DOR, and PFS; overall survival (OS); and safety. Efficacy was evaluated in patients with platinum-resistant and platinum-sensitive disease.

RESULTS

Among 43 patients (median follow-up, 12.3 [range, 8.1-20.1] mo), investigator-assessed ORR was 41.9% (95% confidence interval [CI]: 27.0%-57.9%), with 18 confirmed partial responses; median (95% CI) DOR, PFS, and OS were 4.73 (3.52-6.70), 4.40 (3.81-6.11), and 13.60 (6.57-14.78) months, respectively. The efficacy results of the blinded independent central review assessments were similar. The investigator-assessed ORR (95% CI) was 35.0% (15.4%-59.2%) in patients with platinum-resistant disease (n = 20) and 47.8% (26.8%-69.4%) in patients with platinum-sensitive disease (n = 23). Furthermore, 32 patients (74.4%) had grade greater than or equal to 3 treatment-emergent adverse events (TEAEs). No TEAE led to SG discontinuation; one treatment-related TEAE (neutropenic sepsis) led to death.

CONCLUSIONS

SG has promising efficacy as second-line treatment of ES-SCLC, irrespective of platinum sensitivity. Safety was manageable and consistent with that observed in other SG studies.

Impact of DLL3 Expression as Prognostic Factor in Extensive Stage of Small Cell Lung Cancer Treated With First-Line Chemotherapy

INTRODUCTION

Small cell lung cancer (SCLC) is known for its high proliferative rate and poor prognosis. Although Delta-like ligand 3 (DLL3) is specifically expressed on the surface of SCLC, the association of DLL3 with prognosis in SCLC remains uncertain. Hence, we aimed to evaluate prognostic role of DLL3 in extensive stage of SCLC treated with first-line chemotherapy.

MATERIALS AND METHODS

A total of 54 patients with extensive stage of SCLC (ES-SCLC) who were treated with first-line chemotherapy were included for our analysis. In addition, tissue specimen should be available for immuno-histochemical staining for DLL3, and their clinico-pathologic data, including progression-free survival (PFS) and overall survival (OS), were obtained. DLL3 expression and the percentage of tumor cells with DLL3 positive among total cancer cells were analyzed microscopically and DLL3 high and DLL3 low were defined as the percentage of DLL3 positive tumor cells versus total cancer cells ≧ 75% and < 75%, respectively.

RESULTS

DLL3 expression was not associated with any of the clinico-pathological characteristics such as age at diagnosis, sex, response to first-line chemotherapy, second-line chemotherapy (Yes or No), and number of metastatic sites. However, response to first-line chemotherapy and number of metastatic sites were correlated to PFS, while DLL3 expression and number of metastatic sites were correlated to OS.

CONCLUSION

DLL3 was highly expressed in SCLC, and not associated with any clinico-pathological characteristics. In survival outcome, DLL3 was correlated with worse OS, which suggests the prognostic role of DLL3 in ES-SCLC.

PK/PD Evaluation of Antibody-Drug Conjugates with Enhanced Immune Effector Functions

Optimizing the interaction between antibody (mAb)-based therapeutics and immune effector functions (EFs) offers opportunities to improve the therapeutic window of these molecules. However, the role of EFs in antibody-drug conjugate (ADC) efficacy and toxicity remains unknown, with limited studies that have investigated how modulation of EF affects the pharmacology of ADCs. This study aimed to evaluate the effect of EF modulation on ADC efficacy using trastuzumab-vc-MMAE as a model ADC. A series of ADCs with enhanced or eradicated EF were synthesized through Fc engineering of the antibody. Cell-based assays confirmed that the alteration of EFs in ADCs did not change their in vitro potency, and the conjugation of vc-MMAE did not alter the trends in EFs modulation. Pharmacokinetic/pharmacodynamic (PK/PD) studies of Fc engineered ADCs were conducted in a syngeneic mouse system. The enhancement of EFs led to lower systemic exposure, faster clearance, and potentially enhanced tissue distribution and accumulation of ADCs. ADCs with enhanced EFs demonstrated improved efficacy in the syngeneic mouse tumor model, which was quantitatively confirmed by PK/PD modeling. The model indicated that EF enhancement was synergistic for ADC efficacy, whereas the complete removal of EF was less than additive. Our study suggests that developing ADCs with enhanced EF may improve the therapeutic effectiveness of ADCs, although the effect of this modification on ADC safety and extrapolation of our findings to other ADCs necessitates further investigation.

The Role of Antibody-Drug Conjugates in Urothelial Cancer: A Review of Recent Advances in the Treatment of Locally Advanced and Metastatic Urothelial Cancer

Locally advanced and metastatic urothelial cancer (la/mUC) is an aggressive disease with poor prognosis. Platinum-based chemotherapy has remained the first-line treatment for decades and until recently no other treatment options existed. Today, novel agents called antibody drug conjugates (ADCs), including enfortumab vedotin (EV) and sacituzumab govitecan (SG), have been approved for la/mUC offering patients treatment options following or instead of traditional chemotherapy. The EV consists of the chemotherapy monomethyl auristatin E linked to anti-nectin-4 antibody. Single-agent response rates for EV are 40% to 52% including activity in patients with liver metastases, a phenotype associated with worse outcomes. In 2023, EV in combination with pembrolizumab almost doubled progression-free and overall survival versus platinum-based chemotherapy, which led to accelerated FDA approval as first-line treatment for all patients with la/mUC. Safety profile of EV monotherapy and combination with pembrolizumab is generally manageable with peripheral neuropathy and cutaneous toxicity among the most common treatment-related adverse events (TRAEs). The SG is another ADC targeting TROP-2 with SN-38 as payload. It is approved as late-line treatment for la/mUC with ORR 27% and most common TRAEs include gastrointestinal symptoms and neutropenia. Finally, a recent cancer agnostic accelerated approval for trastuzumab deruxtecan (T-DXd) in HER2-positive (IHC3+) solid tumors provides another active ADC option for biomarker-selected patients with treatment refractory la/mUC. Several new ADCs are being investigated in urothelial cancer (UC) clinical trials. This review summarizes the clinical studies and real-world data regarding the use of ADCs in UC.

Advances in biomarkers for immunotherapy in small-cell lung cancer

Small-cell lung cancer (SCLC) is a refractory cancer with rapid growth and high aggressiveness. Extensive-stage SCLC is initially sensitive to chemotherapy; however, drug resistance and recurrence occur rapidly, resulting in a poor survival outcome due to lack of subsequently efficient therapy. The emergence of immune checkpoint inhibitors (ICIs) generated a new landscape of SCLC treatment and significantly prolonged the survival of patients. However, the unselected immunotherapy restrains both beneficiary population and responsive period in SCLC compared to the other tumors. The complex tumor origin, high heterogeneity, and immunosuppressive microenvironment may disturb the value of conventional biomarkers in SCLC including programmed cell death 1 ligand 1 and tumor mutation burden. Transcriptional regulator-based subtypes of SCLC are current research hotspot, revealing that Y (I) subtype can benefit from ICIs. Additionally, molecules related to immune microenvironment, immunogenicity, epigenetics, and SCLC itself also indicated the therapeutic benefits of ICIs, becoming potential predictive biomarkers. In this review, we discussed the advances of biomarkers for prediction and prognosis of immunotherapy, promising directions in the future, and provide reference and options for precision immunotherapy and survival improvement in patients with SCLC.

Advances in DLL3-targeted therapies for small cell lung cancer: challenges, opportunities, and future directions

Small cell lung cancer (SCLC) remains one of the most aggressive and challenging malignancies to treat, with limited therapeutic options and poor outcomes. Recent advances in understanding SCLC biology have identified Delta-like ligand 3 (DLL3) as a promising target for novel therapies. This review explores the evolving landscape of DLL3-targeted therapies in SCLC, examining their mechanistic basis, preclinical promise, and clinical development. We discuss various therapeutic modalities, including antibody-drug conjugates (ADCs), bispecific T-cell engagers (BiTEs), chimeric antigen receptor T-cell (CAR-T) therapies, and emerging approaches such as near-infrared photoimmunotherapy (NIR-PIT) and radiopharmaceutical therapy (RPT). The review highlights the challenges encountered in translating these promising approaches into clinical practice, including the setbacks faced by early DLL3-targeted therapies like Rovalpituzumab Tesirine (Rova-T). We also explore potential strategies to overcome these obstacles, emphasizing the need for a more nuanced understanding of DLL3 biology and its role in SCLC pathogenesis. The integration of cutting-edge technologies and interdisciplinary collaboration is proposed as a path forward to optimize DLL3-targeted therapies and improve outcomes for SCLC patients. This comprehensive overview provides insights into the current state and future directions of DLL3-targeted therapies, underscoring their potential to revolutionize SCLC treatment paradigms.

DLL3 as a potential diagnostic and therapeutic target in neuroendocrine neoplasms: A narrative review

Neuroendocrine neoplasms (NENs) represent a diagnostic and therapeutic challenge, due to their heterogeneity and limited treatment options. Conventional imaging techniques and therapeutic strategies may become unreliable during follow-up, due to the tendency of these neoplasms to dedifferentiate over time. Therefore, novel diagnostic and therapeutic options are required for the management of NEN patients. Delta-like ligand 3 (DLL3), an inhibitory ligand of Notch receptor, has emerged as a potential target for novel diagnostic and therapeutic strategies in NENs, since overexpression of DLL3 has been associated with tumor progression, poor prognosis and dedifferentiation in several NENs. This narrative review examines the current evidence about DLL3, its structure, function and association with tumorigenesis in NENs. Ongoing studies exploring the role of DLL3 as an emerging diagnostic marker are reviewed. Promising therapeutic options, such as antibody-conjugated drugs, CAR-T cells and radioimmunoconjugates, are also discussed.

Phase 1 first-in-human study of MEDI2228, a BCMA-targeted ADC, in patients with relapsed refractory multiple myeloma

MEDI2228 is an antibody drug conjugate (ADC) comprised of a fully human B-cell maturation antigen (BCMA) antibody conjugated to a pyrrolobenzodiazepine (PBD) dimer. This phase 1 trial evaluated MEDI2228 in patients with relapsed/refractory (R/R) multiple myeloma (MM), who received prior treatment with approved agents from 3 classes of antimyeloma drugs (proteasome inhibitors, immunomodulatory drugs, and monoclonal antibodies). Primary endpoint was safety and tolerability; secondary endpoints included efficacy, pharmacokinetics, and immunogenicity. A total of 107 patients were treated and the maximum tolerated dose (MTD) was 0.14 mg/kg Q3W. Two patients had dose-limiting toxicities (DLTs; thrombocytopenia; 0.20 mg/kg Q3W). The most frequent treatment-related adverse events were photophobia (43.9%), rash (29.0%), and thrombocytopenia (19.6%). In MTD cohort A (n = 41), the objective response rate (ORR) was 56.1%, with 1 stringent complete response, 9 very good partial responses, and 13 partial responses. ORR was 53.3% in triple refractory patients. In cohort B (n=25), ORR was 32%. Although MEDI2228 demonstrated efficacy in R/R MM, ocular toxicity precluded further development of this drug.

Small cell lung cancer with liver metastases: from underlying mechanisms to treatment strategies

Small cell lung cancer (SCLC) represents an aggressive neuroendocrine (NE) tumor within the pulmonary region, characterized by very poor prognoses. Druggable targets for SCLC remain limited, thereby constraining treatment options available to patients. Immuno-chemotherapy has emerged as a pivotal therapeutic strategy for extensive-stage SCLC (ES-SCLC), yet it fails to confer significant efficacy in cases involving liver metastases (LMs) originating from SCLC. Therefore, our attention is directed towards the challenging subset of SCLC patients with LMs. Disease progression of LM-SCLC patients is affected by various factors in the tumor microenvironment (TME), including immune cells, blood vessels, inflammatory mediators, metabolites, and NE substances. Beyond standard immuno-chemotherapy, ongoing efforts to manage LMs in SCLC encompass anti-angiogenic therapy, radiotherapy, microwave ablation (MWA) / radiofrequency ablation (RFA), trans-arterial chemoembolization (TACE), and systemic therapies in conjunction with local interventions. Prospective experimental and clinical investigations into SCLC should prioritize precise and individualized approaches to enhance the prognosis across distinct patient cohorts.

Delta-like ligand 3 (DLL3) landscape in pulmonary and extra-pulmonary neuroendocrine neoplasms

Delta-like Ligand 3 (DLL3) targeting therapies are promising in small cell lung cancer (SCLC) treatment. However, DLL3 expression in SCLC and other neuroendocrine neoplasms (NEN) is heterogeneous and not well characterized. We describe the landscape of DLL3 at the mRNA and protein levels across SCLC, large cell neuroendocrine carcinoma (LCNEC), and non-small cell lung cancer. Additionally, we explore its expression in extra-pulmonary NEN (EP-NEN) using a standardized DLL3 IHC assay. DLL3 expression is enriched in SCLC, LCNEC along with combined histology lung cancers. Moreover, we find a wide range of DLL3 expression in high-grade EP-NEN. We describe heterogenous DLL3 expression not only in SCLC but also in different NEN types. This comprehensive characterization of DLL3 can help guide future clinical trial design targeting DLL3 in NEN including LCNEC and EP-NEN that are lacking standard of care treatment options.

A Phase I First-in-Human Study of ABBV-011, a Seizure-Related Homolog Protein 6-Targeting Antibody-Drug Conjugate, in Patients with Small Cell Lung Cancer

PURPOSE

Seizure-related homolog protein 6 (SEZ6) is a novel target expressed in small cell lung cancer (SCLC). ABBV-011, a SEZ6-targeted antibody conjugated to calicheamicin, was evaluated in a phase I study (NCT03639194) in patients with relapsed/refractory SCLC. We report initial outcomes of ABBV-011 monotherapy.

PATIENTS AND METHODS

ABBV-011 was administered intravenously once every 3 weeks during dose escalation (0.3-2 mg/kg) and expansion. Patients with SEZ6-positive tumors (≥25% of tumor cells with ≥1+ staining intensity by IHC) were preselected for expansion. Safety, tolerability, antitumor activity, and pharmacokinetics were evaluated.

RESULTS

As of August 2022, 99 patients received ABBV-011 monotherapy [dose escalation, n = 36; Japanese dose evaluation, n = 3; dose expansion, n = 60 (1 mg/kg, n = 40)]; the median age was 63 years (range, 41-79 years). Also, 32%, 41%, and 26% of patients received 1, 2, and ≥3 prior therapies, respectively. The maximum tolerated dose was not reached through 2.0 mg/kg. The most common treatment-emergent adverse events were fatigue (50%), nausea (42%), and thrombocytopenia (41%). The most common hepatic treatment-emergent adverse events were increased aspartate aminotransferase (22%), increased γ-glutamyltransferase (21%), and hyperbilirubinemia (17%); two patients experienced veno-occlusive liver disease. The objective response rate was 19% (19/98). In the 1-mg/kg dose-expansion cohort (n = 40), the objective response rate was 25%; the median response duration was 4.2 months (95% confidence interval, 2.6-6.7); and the median progression-free survival was 3.5 months (95% confidence interval, 1.5-4.2).

CONCLUSIONS

ABBV-011 1.0 mg/kg every 3 weeks monotherapy was well tolerated and demonstrated encouraging antitumor activity in heavily pretreated patients with relapsed/refractory SCLC. SEZ6 is a promising novel SCLC target and warrants further investigation.

Current Status and Future Prospects of TROP-2 ADCs in Lung Cancer Treatment

Lung cancer is the leading cause of mortality worldwide, and non-small cell lung cancer accounts for the majority of lung cancer cases. Chemotherapy and radiotherapy constitute the mainstays of lung cancer treatment; however, their associated side effects involving the kidneys, nervous system, gastrointestinal tract, and liver further add to dismal outcomes. The advent of antibody‒drug conjugates (ADCs) could change this situation. Trophoblast surface antigen 2 (TROP-2), a human trophoblast surface antigen, is a tumor-associated antigen that is expressed at low levels in normal tissues and is overexpressed in a variety of malignant tumors. The differential expression of the TROP-2 protein in a variety of tumors makes tumor immunotherapy with ADCs targeting TROP-2 a promising approach. Previous studies have shown that the expression of TROP-2 is related to the prognosis of patients with lung cancer and that TROP-2 expression is different across different histological types; however, research on TROP-2 and TROP-2 ADCs in patients with lung cancer is not comprehensive. The aims of this study were to review the mechanism of action and clinical efficacy of TROP-2 and related drugs in the treatment of lung cancer, to elucidate the prognostic value of TROP-2 in lung cancer, and to discuss the future prospects of TROP-2 ADCs to provide a reference for the precise treatment of lung cancer.

Recent advances in immunotherapy for small cell lung cancer

PURPOSE OF REVIEW

This review aims to provide an overview of recent advances in immunotherapy for small cell lung cancer (SCLC), with a focus on the current status of immune checkpoint inhibitors (ICIs), novel combination strategies, and key biomarkers.

RECENT FINDINGS

The integration of ICIs into standard chemotherapy has established them as the first-line treatment for extensive-stage SCLC (ES-SCLC). The ADRIATIC trial further demonstrated the efficacy of ICI maintenance therapy in limited-stage SCLC. Additionally, combining radiotherapy with ICIs has shown promising synergistic effects, including the abscopal and radscopal effects. Ongoing investigations into the combination of ICIs with targeted therapies, such as antiangiogenic agents and DNA damage response inhibitors, have yielded encouraging preliminary results. Notably, the novel therapeutic agent tarlatamab, the first bispecific DLL3-directed CD3 T-cell engager, has recently received FDA approval for second-line treatment of ES-SCLC. Advances in omics technologies have shed light on the intra-tumor and inter-tumor heterogeneity of SCLC, leading to the identification of new molecular subtypes and biomarkers, thereby paving the way for precision medicine.

SUMMARY

Despite the improved outcomes associated with immunotherapy in SCLC, the overall clinical benefit remains modest. Further preclinical and clinical studies are essential to identify optimal treatment regimens and enhance therapeutic efficacy.

Efficacy and toxicity of lurbinectedin in subsequent systemic therapy of extensive-stage small cell lung cancer: a meta-analysis

OBJECTIVE

This study aimed to systematically analyze the efficacy and toxicity of lurbinectedin as a second-line or subsequent treatment for extensive-stage small cell lung cancer (ES-SCLC).

METHODS

Candidate studies were identified in PubMed, Embase, Cochrane Library, ClinicalTrials.gov, CNKI, and Wanfang databases up to 1 May 2024. Objective remission rate (ORR), disease control rate (DCR), duration of response (DOR), progression-free survival (PFS), overall survival (OS), and adverse events (AEs) were extracted, respectively. The efficacy and toxicity of lurbinectedin in ES-SCLC were analyzed by meta-analysis.

RESULTS

Six eligible prospective studies were included in this meta-analysis, including 536 patients with ES-SCLC who received second-line or subsequent treatment. In pooled analysis, the ORR of lurbinectedin was 35% (95% confidence interval [CI] 29-41), DCR was 67% (95%CI 58-76), DOR was 5.33 months (95%CI 4.51-6.16), PFS was 3.38 months (95%CI 2.59-4.17), and OS was 7.49 months (95%CI 5.11-9.87). The incidence of AEs and severe adverse events (SAEs) was 92% (95%CI 78-100) and 37% (95%CI 19-57), respectively. The most common AEs were leukopenia, neutropenia, anemia, and thrombocytopenia, with incidences of 81% (68-91), 74% (57-88), 73% (35-98) and 57% (46-68), respectively.

CONCLUSION

As a promising alternative for second-line treatment for ES-SCLC, lurbinectedin has a certain level of efficacy and a favorable safety profile. The integration of lurbinectedin with other therapeutic modalities presents an emerging area warranting further investigation.

CAR-T cell therapy: Challenge and opportunity for effective treatment of small cell lung cancer

Small cell lung cancer (SCLC) is a devastating malignancy characterized by rapid metastasis, drug resistance, and frequent recurrence. Owing to the paucity of existing therapeutic options, the prognosis of SCLC remains poor. Recently, the combination of immune checkpoint inhibitors and chemotherapy has resulted in modest improvements in treatment responses. In this review, we characterize the biological signature of SCLC and outline the obstacles to current treatment, including impaired antigen presentation and T cell infiltration. These obstacles may potentially be overcome by chimeric antigen receptor (CAR)-T cell therapy. For the first time, we summarize the available data and discuss the future prospects of CAR-T cell therapy for the treatment of SCLC. Given the high heterogeneity and immunosuppressive tumor microenvironment of SCLC, structural modifications of CAR-T cells and combination therapy may be required to elicit a successful antitumor response. Further research, including clinical trials, is needed to determine the suitability of CAR-T cell therapy as a treatment for SCLC.

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.

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.

Present Scenario and Future Landscape of Payloads for ADCs: Focus on DNA-Interacting Agents

ADCs have emerged as a promising class of therapeutics, combining the targeting specificity of monoclonal antibodies with the cytotoxic potency of small-molecule drugs. Although the majority of approved ADCs are still based on microtubule binder payloads, the recent success of topoisomerase I inhibitors has revitalized interest in the identification of novel agents overcoming present limitations in the field including narrow therapeutic window and chemoresistance. The success of DNA binders as payload for ADCs has been very limited, up to now, due, among other factors, to high hydrophobicity and planar chemical structures resulting in most cases in ADCs with a strong tendency to aggregate, poor plasma stability, and limited therapeutic index. Some of these molecules, however, continue to be of interest due to their favorable properties in terms of cytotoxic potency even in chemoresistant settings, bystander and immunogenic cell death effects, and known combinability with approved drugs. We critically evaluated several clinically tested ADCs containing DNA binders, focusing on payload physicochemical properties, cytotoxic potency, and obtained clinical results. Our analysis suggests that further exploration of certain chemical classes, specifically anthracyclines and duocarmycins, based on the optimization of physicochemical parameters, reduction of cytotoxic potency, and careful design of targeting molecules is warranted. This approach will possibly result in a novel generation of payloads overcoming the limitations of clinically validated ADCs.

Differential NEUROD1, ASCL1, and POU2F3 Expression Defines Molecular Subsets of Bladder Small Cell/Neuroendocrine Carcinoma With Prognostic Implications

Small cell carcinomas (SMC) of the lung are now molecularly classified based on the expression of transcriptional regulators (NEUROD1, ASCL1, POU2F3, and YAP1) and DLL3, which has emerged as an investigational therapeutic target. PLCG2 has been shown to identify a distinct subpopulation of lung SMC with stem cell-like and prometastasis features and poor prognosis. We analyzed the expression of these novel neuroendocrine markers and their association with traditional neuroendocrine markers and patient outcomes in a cohort of bladder neuroendocrine carcinoma (NEC) consisting of 103 SMC and 19 large cell NEC (LCNEC) assembled in tissue microarrays. Coexpression patterns were assessed and integrated with detailed clinical annotation including overall (OS) and recurrence-free survival (RFS) and response to neoadjuvant/adjuvant chemotherapy. We identified 5 distinct molecular subtypes in bladder SMC based on the expression of ASCL1, NEUROD1, and POU2F3: ASCL1+/NEUROD1- (n = 33; 34%), ASCL1- /NEUROD1+ (n = 21; 21%), ASCL1+/NEUROD1+ (n = 17; 17%), POU2F3+ (n = 22, 22%), and ASCL1- /NEUROD1- /POU2F3- (n = 5, 5%). POU2F3+ tumors were mutually exclusive with those expressing ASCL1 and NEUROD1 and exhibited lower expression of traditional neuroendocrine markers. PLCG2 expression was noted in 33 tumors (32%) and was highly correlated with POU2F3 expression (P < .001). DLL3 expression was high in both SMC (n = 72, 82%) and LCNEC (n = 11, 85%). YAP1 expression was enriched in nonneuroendocrine components and negatively correlated with all neuroendocrine markers. In patients without metastatic disease who underwent radical cystectomy, PLCG2+ or POU2F3+ tumors had shorter RFS and OS (P < .05), but their expression was not associated with metastasis status or response to neoadjuvant/adjuvant chemotherapy. In conclusion, the NEC of the bladder can be divided into distinct molecular subtypes based on the expression of ASCL1, NEUROD1, and POU2F3. POU2F3-expressing tumors represent an ASCL1/NEUROD1-negative subset of bladder NEC characterized by lower expression of traditional neuroendocrine markers. Marker expression patterns were similar in SMC and LCNEC. Expression of PLCG2 and POU2F3 was associated with shorter RFS and OS. DLL3 was expressed at high levels in both SMC and LCNEC of the bladder, nominating it as a potential therapeutic target.

Neuroendocrine transdifferentiation in human cancer: molecular mechanisms and therapeutic targets

Neuroendocrine transdifferentiation (NEtD), also commonly referred to as lineage plasticity, emerges as an acquired resistance mechanism to molecular targeted therapies in multiple cancer types, predominately occurs in metastatic epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer treated with EGFR tyrosine kinase inhibitors and metastatic castration-resistant prostate cancer treated with androgen receptor targeting therapies. NEtD tumors are the lethal cancer histologic subtype with unfavorable prognosis and limited treatment. A comprehensive understanding of molecular mechanism underlying targeted-induced plasticity could greatly facilitate the development of novel therapies. In the past few years, increasingly elegant studies indicated that NEtD tumors share key the convergent genomic and phenotypic characteristics irrespective of their site of origin, but also embrace distinct change and function of molecular mechanisms. In this review, we provide a comprehensive overview of the current understanding of molecular mechanism in regulating the NEtD, including genetic alterations, DNA methylation, histone modifications, dysregulated noncoding RNA, lineage-specific transcription factors regulation, and other proteomic alterations. We also provide the current management of targeted therapies in clinical and preclinical practice.

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.

Anlotinib plus oral fluoropyrimidine S-1 in refractory or relapsed small-cell lung cancer (SALTER TRIAL): a multicenter, single-arm, phase II trial

BACKGROUND

Patients with small-cell lung cancer (SCLC) have few treatment options and dismal overall survival (OS) after failed platinum-based chemotherapy.

METHODS

The eligibility criteria of this phase II clinical trial included patients with measurable disease, age of 18 to 75 years, a confirmed diagnosis of disease progression or recurrence after prior platinum-based chemotherapy with a pathologically proven diagnosis of SCLC. Patients were treated with anlotinib at a dosage of 12 mg once daily (QD) and S-1 at 60 mg twice daily (BID) for 2 weeks, followed by a 1-week treatment-free interval. After six cycles of the above treatment, patients continued the maintenance therapy using S-1 monotherapy at 60 mg/ BID for 2 weeks, followed by a 1-week treatment-free interval until disease progression.

RESULTS

From March 2019 to June 2020, a total of 71 patients were initially assessed for eligibility in this study. Out of these, 52 patients who met the inclusion criteria were enrolled, and 48 patients received at least two doses of the study drug. The median follow-up time was 25.1 months. The ORR was seen in 21 patients (43.8%). The median PFS was 4.5 months (95% CI, 3.5-5.5 months), and the median OS was 5.9 months (95% CI, 4.6-7.3 months). The most common grade 3-4 treatment-related adverse events were thrombocytopenia (16.7%), anemia (14.6%), neutropenia (14.6%), and hypertension (10.4%). No treatment-related death occurred.

CONCLUSIONS

The combination of anlotinib with oral fluoropyrimidine S-1 demonstrated notable activity in relapsed or refractory SCLC, showing a favorable ORR and an acceptable, manageable safety profile.

TRIAL REGISTRATION

This trial was registered with ClinicalTrial.gov (NCT03823118) on 3 January 2019.

Developmental Therapeutics in Metastatic Prostate Cancer: New Targets and New Strategies

There is an unmet need to develop new treatments for metastatic prostate cancer. With the development of targeted radioligand therapies, bispecific T cell engagers, antibody-drug conjugates and chimeric antigen receptor T cell (CAR T) therapies, tumor-associated cell surface antigens have emerged as new therapeutic targets in metastatic prostate cancer. Ongoing and completed clinical trials targeting prostate-specific membrane antigen (PSMA), six transmembrane epithelial antigens of the prostate 1 (STEAP1), kallikrein-related peptidase 2 (KLK2), prostate stem cell antigen (PSCA), and delta-like protein 3 (DLL3) in metastatic prostate cancer were reviewed. Strategies for sequential or combinational therapy were discussed.

The cellular-centered view of hypoxia tumor microenvironment: Molecular mechanisms and therapeutic interventions

Cancer is a profoundly dynamic, heterogeneous and aggressive systemic ailment, with a coordinated evolution of various types of tumor niches. Hypoxia plays an indispensable role in the tumor micro-ecosystem, drastically enhancing the plasticity of cancer cells, fibroblasts and immune cells and orchestrating intercellular communication. Hypoxia-induced signals, particularly hypoxia-inducible factor-1α (HIF-1α), drive the reprogramming of genetic, transcriptional, and proteomic profiles. This leads to a spectrum of interconnected processes, including augmented survival of cancer cells, evasion of immune surveillance, metabolic reprogramming, remodeling of the extracellular matrix, and the development of resistance to conventional therapeutic modalities like radiotherapy and chemotherapy. Here, we summarize the latest research on the multifaceted effects of hypoxia, where a multitude of cellular and non-cellular elements crosstalk with each other and co-evolve in a synergistic manner. Additionally, we investigate therapeutic approaches targeting hypoxic niche, encompassing hypoxia-activated prodrugs, HIF inhibitors, nanomedicines, and combination therapies. Finally, we discuss some of the issues to be addressed and highlight the potential of emerging technologies in the treatment of cancer.

Small cell lung cancer: emerging subtypes, signaling pathways, and therapeutic vulnerabilities

Small cell lung cancer (SCLC) is a recalcitrant cancer characterized by early metastasis, rapid tumor growth and poor prognosis. In recent decades, the epidemiology, initiation and mutation characteristics of SCLC, as well as abnormal signaling pathways contributing to its progression, have been widely studied. Despite extensive investigation, fewer drugs have been approved for SCLC. Recent advancements in multi-omics studies have revealed diverse classifications of SCLC that are featured by distinct characteristics and therapeutic vulnerabilities. With the accumulation of SCLC samples, different subtypes of SCLC and specific treatments for these subtypes were further explored. The identification of different molecular subtypes has opened up novel avenues for the treatment of SCLC; however, the inconsistent and uncertain classification of SCLC has hindered the translation from basic research to clinical applications. Therefore, a comprehensives review is essential to conclude these emerging subtypes and related drugs targeting specific therapeutic vulnerabilities within abnormal signaling pathways. In this current review, we summarized the epidemiology, risk factors, mutation characteristics of and classification, related molecular pathways and treatments for SCLC. We hope that this review will facilitate the translation of molecular subtyping of SCLC from theory to clinical application.

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.