Managing Patients With Relapsed Small-Cell Lung Cancer

Molecular mechanisms underlying the regulation of tumour suppressor genes in lung cancer

Tumour suppressor genes play a cardinal role in the development of a large array of human cancers, including lung cancer, which is one of the most frequently diagnosed cancers worldwide. Therefore, extensive studies have been committed to deciphering the underlying mechanisms of alterations of tumour suppressor genes in governing tumourigenesis, as well as resistance to cancer therapies. In spite of the encouraging clinical outcomes demonstrated by lung cancer patients on initial treatment, the subsequent unresponsiveness to first-line treatments manifested by virtually all the patients is inherently a contentious issue. In light of the aforementioned concerns, this review compiles the current knowledge on the molecular mechanisms of some of the tumour suppressor genes implicated in lung cancer that are either frequently mutated and/or are located on the chromosomal arms having high LOH rates (1p, 3p, 9p, 10q, 13q, and 17p). Our study identifies specific genomic loci prone to LOH, revealing a recurrent pattern in lung cancer cases. These loci, including 3p14.2 (FHIT), 9p21.3 (p16INK4a), 10q23 (PTEN), 17p13 (TP53), exhibit a higher susceptibility to LOH due to environmental factors such as exposure to DNA-damaging agents (carcinogens in cigarette smoke) and genetic factors such as chromosomal instability, genetic mutations, DNA replication errors, and genetic predisposition. Furthermore, this review summarizes the current treatment landscape and advancements for lung cancers, including the challenges and endeavours to overcome it. This review envisages inspired researchers to embark on a journey of discovery to add to the list of what was known in hopes of prompting the development of effective therapeutic strategies for lung cancer.

Induced degradation of lineage-specific oncoproteins drives the therapeutic vulnerability of small cell lung cancer to PARP inhibitors

Although BRCA1/2 mutations are not commonly found in small cell lung cancer (SCLC), a substantial fraction of SCLC shows clinically relevant response to PARP inhibitors (PARPis). However, the underlying mechanism(s) of PARPi sensitivity in SCLC is poorly understood. We performed quantitative proteomic analyses and identified proteomic changes that signify PARPi responses in SCLC cells. We found that the vulnerability of SCLC to PARPi could be explained by the degradation of lineage-specific oncoproteins (e.g., ASCL1). PARPi-induced activation of the E3 ligase HUWE1 mediated the ubiquitin-proteasome system (UPS)-dependent ASCL1 degradation. Although PARPi induced a general DNA damage response in SCLC cells, this signal generated a cell-specific response in ASCL1 degradation, leading to the identification of HUWE1 expression as a predictive biomarker for PARPi. Combining PARPi with agents targeting these pathways markedly improved therapeutic response in SCLC. The degradation of lineage-specific oncoproteins therefore represents a previously unidentified mechanism for PARPi efficacy in SCLC.

Benefits and risks of PD-1/PD-L1 inhibitors for recurrent small cell lung cancer: A systematic review and meta-analysis

The development of immune checkpoint inhibitors(ICIs) has revolutionized the progress of solid tumors. Ongoing clinical trials are exploring the use of checkpoint inhibitors in recurrent small-cell lung cancer and achieving specific results. Although studies have been conducted to systematically review this issue, we conducted this single-arm meta-analysis in light of the emergence of several new clinical studies. In total, 854 individuals from 11 clinical investigations were enrolled in this single-arm meta-analysis. Median progression-free survival, median overall survival, and objective response rate were 1.65 months, 6.83 months, and 20.5%, respectively, according to pooled analyses. The best treatment regimen in the subgroup analysis was a dual checkpoint inhibitor combined with other treatments, and the drug that worked well for treatment was pembrolizumab. The benefit of programmed death 1/programmed cell death-ligand 1(PD-1/PD-L1) inhibitors alone is limited, and their combination with other therapies is a promising treatment option. Among PD-1/PD-L1 inhibitors, pembrolizumab is the recommended drug.

Real-world predictors of survival in patients with limited-stage small-cell lung cancer in Manitoba, Canada

Background

Although therapy for limited-stage small-cell lung cancer (LS-SCLC) is administered with curative intent, most patients relapse and eventually die of recurrent disease. Chemotherapy (CT) with concurrent radiotherapy (RT) remains the standard of care for LS-SCLC; however, this could evolve in the near future. Therefore, understanding the current prognostic factors associated with survival is essential.

Objective

This real-world analysis examines factors associated with long-term survival in patients with LS-SCLC treated with CT in Manitoba, Canada.

Methods

A retrospective cohort study was conducted using Manitoba Cancer Registry and CancerCare Manitoba records. Eligible patients were aged >18 years and had cytologically confirmed LS-SCLC diagnosed between January 1, 2004, and December 31, 2018, for which they received CT ± RT. Baseline patient, disease, and treatment characteristics and survival duration, characterized as short (<6 months), medium (6-24 months), and long term (>24 months), were extracted. Overall survival (OS) was estimated at one, two, and five years and assessed using Kaplan-Meier methods and Cox proportional hazards models.

Results

Over the 15-year study period, 304 patients met the eligibility criteria. Long-term survivors comprised 39.1% of the cohort; at diagnosis, this subgroup was younger, more likely to have Eastern Cooperative Oncology Group Performance Status (ECOG PS) 0, and have normal lactate dehydrogenase, sodium, and hemoglobin levels. OS estimates for the entire cohort at one, two, and five years were 66%, 38%, and 18%, respectively. In the ECOG PS 0 subgroup, OS estimates at one, two, and five years were 85%, 52%, and 24%, respectively; OS estimates were 60%, 35%, and 17%, respectively, for ECOG PS 1-2 and were 47%, 23%, and 10%, respectively, for ECOG PS 3-4. OS was significantly higher among patients with normal serum sodium and hemoglobin levels than those with abnormal levels. Univariable hazard regression models found that ECOG PS, age at diagnosis, receipt of prophylactic cranial irradiation (PCI), and thoracic RT were associated with survival. On multivariable hazard regression, ECOG PS and receipt of PCI were associated with survival.

Conclusion

Survival for greater than two years in patients with LS-SCLC treated with CT ± RT was associated with ECOG PS and receipt of PCI.

Real-world utilization of immune checkpoint inhibitors in extensive stage small-cell lung cancer in community settings

Aim: This study examined real-world treatment patterns for extensive-stage small-cell lung cancer (ES-SCLC) after immune checkpoint inhibitors (ICIs) became available for frontline use. Methods: Adult patients with ES-SCLC initiating 1L systemic treatment were identified from electronic health records. Results: Among patients with recurrent/progressive ES-SCLC, the most common treatment classes were platinum-based chemotherapy (81.1% of 228) and ICI monotherapy (35.1% of 191) in 1L and 2L, respectively. Among patients with de novo ES-SCLC, the most common treatment classes were ICI + platinum-based chemotherapy (64.4% of 1268) and other chemotherapy (44.9% of 512) in 1L and 2L, respectively. Among patients who received no ICI in 1L, 62.6%-70.3% received it in 2L and 62.6-68.5% in 3L. Some who received 1L ICI were re-treated with ICI in subsequent lines (14.5-18.8% in 2L, 18.2-50.0% in 3L). Conclusion: Real-world ICI utilization in ES-SCLC, particularly ICI re-challenge, demonstrates high unmet needs in this patient population.

Indirect treatment comparison of lurbinectedin versus other second-line treatments for small-cell lung cancer

Aim: Compare lurbinectedin versus other second-line (2L) small-cell lung cancer (SCLC) treatments. Methods: An unanchored matching-adjusted indirect comparison connected the platinum-sensitive SCLC cohort of a single-arm lurbinectedin trial to a network of three randomized controlled trials (oral and intravenous [IV] topotecan, and platinum re-challenge) identified by systematic literature review. Network meta-analysis methods estimated relative treatment effects. Results: In platinum-sensitive patients, lurbinectedin demonstrated a survival benefit and favorable safety profile versus oral and IV topotecan and platinum re-challenge (overall survival, hazard ratio [HR]: 0.43; 95% credible interval [CrI]: 0.27, 0.67; HR: 0.43; 95% CrI: 0.26, 0.70; HR: 0.42; 95% CrI: 0.30, 0.58 respectively). Conclusion: Lurbinectedin showed a robust survival benefit and favorable safety versus other SCLC treatments in 2L platinum-sensitive SCLC.

Dual targeting of BCL-2 and MCL-1 in the presence of BAX breaks venetoclax resistance in human small cell lung cancer

BACKGROUND

No targeted drugs are currently available against small cell lung cancer (SCLC). BCL-2 family members are involved in apoptosis regulation and represent therapeutic targets in many malignancies.

METHODS

Expression of BCL-2 family members in 27 SCLC cell lines representing all known four SCLC molecular subtypes was assessed by qPCR, Western blot and mass spectrometry-based proteomics. BCL-2 and MCL-1 inhibition (venetoclax and S63845, respectively) was assessed by MTT assay and flow cytometry and in mice bearing human SCLC tumours. Drug interactions were calculated using the Combenefit software. Ectopic BAX overexpression was achieved by expression plasmids.

RESULTS

The highest BCL-2 expression levels were detected in ASCL1- and POU2F3-driven SCLC cells. Although sensitivity to venetoclax was reflected by BCL-2 levels, not all cell lines responded consistently despite their high BCL-2 expression. MCL-1 overexpression and low BAX levels were both characteristic for venetoclax resistance in SCLC, whereas the expression of other BCL-2 family members did not affect therapeutic efficacy. Combination of venetoclax and S63845 resulted in significant, synergistic in vitro and in vivo anti-tumour activity and apoptosis induction in double-resistant cells; however, this was seen only in a subset with detectable BAX. In non-responding cells, ectopic BAX overexpression sensitised to venetoclax and S63845 and, furthermore, induced synergistic drug interaction.

CONCLUSIONS

The current study reveals the subtype specificity of BCL-2 expression and sheds light on the mechanism of venetoclax resistance in SCLC. Additionally, we provide preclinical evidence that combined BCL-2 and MCL-1 targeting is an effective approach to overcome venetoclax resistance in high BCL-2-expressing SCLCs with intact BAX.

Treatment patterns and outcomes among patients with small-cell lung cancer (SCLC) in Europe: a retrospective cohort study

OBJECTIVE

Describe characteristics, treatment patterns and clinical outcomes of patients with small-cell lung cancer (SCLC).

DESIGN

Retrospective chart review study defining several cohorts: (1) limited-stage disease (LD) SCLC initiating 1L therapy (1 L LD-SCLC), (2) extensive-stage disease (ED) SCLC initiating 1L therapy (1L ED-SCLC) and (3) patients initiating 2L therapy.

SETTING

39 physicians (medical oncologists, thoracic oncologists and/or pulmonologists) from France, Italy and the UK.

PARTICIPANTS

Patients >18 years of age with a confirmed diagnosis of LD-SCLC or ED-SCLC and a full oncology medical history. Patients included initiated a 1L (2013-2015) or 2L (2013-2016) treatment (chemotherapy and/or radiotherapy-RT).

PRIMARY AND SECONDARY OUTCOME MEASURES

Overall survival (OS) and progression-free survival (PFS).

RESULTS

231 patients in 1L LD-SCLC, 308 in 1L ED-SCLC and 225 with relapse/refractory SCLC initiating 2L treatment were included. The proportion of men was higher across all groups (56.8% to 68.5%) and mean age at time of diagnosis was 66.0 and 65.4 years in 1L LD-SCLC and 2L ED-SCLC cohorts. The majority of patients in LD-SCLC 1L group received chemotherapy with RT (76.2%). Patients initiating 2L therapy predominantly received chemotherapy alone (79.6%).Median OS in 1 L patients was 17.3 months in LD-SCLC and 8.8 months in ED-SCLC. Median PFS was 11.6 months in LD-SCLC and 6.1 months in ED-SCLC patients. Median OS in patients initiating 2L treatment was 6.6 months. OS from start of 2L treatment was lower in patients initially diagnosed with ED (5.1 months) than in patients initially diagnosed with LD (9.3 months) (p<0.0001). OS and PFS were assessed from the start of 1L or 2L therapy, depending on the cohort.

CONCLUSIONS

Despite the availability of a high number of treatments and combinations, the prognosis of SCLC is still unsatisfactory, especially for those patients diagnosed with ED-SCLC, indicating high unmet need in this patient population.

Antigene MYCN Silencing by BGA002 Inhibits SCLC Progression Blocking mTOR Pathway and Overcomes Multidrug Resistance

Small-cell lung cancer (SCLC) is the most aggressive lung cancer type, and is associated with smoking, low survival rate due to high vascularization, metastasis and drug resistance. Alterations in MYC family members are biomarkers of poor prognosis for a large number of SCLC. In particular, MYCN alterations define SCLC cases with immunotherapy failure. MYCN has a highly restricted pattern of expression in normal cells and is an ideal target for cancer therapy but is undruggable by traditional approaches. We propose an innovative approach to MYCN inhibition by an MYCN-specific antigene-PNA oligonucleotide (BGA002)-as a new precision medicine for MYCN-related SCLC. We found that BGA002 profoundly and specifically inhibited MYCN expression in SCLC cells, leading to cell-growth inhibition and apoptosis, while also overcoming multidrug resistance. These effects are driven by mTOR pathway block in concomitance with autophagy reactivation, thus avoiding the side effects of targeting mTOR in healthy cells. Moreover, we identified an MYCN-related SCLC gene signature comprehending CNTFR, DLX5 and TNFAIP3, that was reverted by BGA002. Finally, systemic treatment with BGA002 significantly increased survival in MYCN-amplified SCLC mouse models, including in a multidrug-resistant model in which tumor vascularization was also eliminated. These findings warrant the clinical testing of BGA002 in MYCN-related SCLC.

Activities against Lung Cancer of Biosynthesized Silver Nanoparticles: A Review

Nanomedicine is an interdisciplinary field where nanostructured objects are applied to treat or diagnose disease. Nanoparticles (NPs) are a special class of materials at nanometric scale that can be prepared from lipids, polymers, or noble metals through bottom-up approaches. Biological synthesis is a reliable, sustainable, and non-toxic bottom-up method that uses phytochemicals, microorganisms, and enzymes to induce the reduction of metal ions into NPs. Silver (Ag) NPs exhibit potent therapeutic properties that can be exploited to overcome the limitations of current treatment modalities for human health issues such as lung cancer (LC). Here, we review the preparation of AgNPs using biological synthesis and their application against LC using in vitro and in vivo models. An overview of the staging, diagnosis, genetic mutations, and treatment of LC, as well as its main subtypes, is presented. A summary of the reaction mechanisms of AgNPs using microbial cell cultures, plant extracts, phytochemicals, and amino acids is included. The use of capping agents in the biosynthesis of AgNPs with anticancer activity is also detailed. The history and biological activities of metal-based nanostructures synthesized with gold, copper, palladium, and platinum are considered. The possible anticancer mechanisms of AgNPs against LC models are covered. Our perspective about the future of AgNPs in LC treatment and nanomedicine is added.

The germline factor DDX4 contributes to the chemoresistance of small cell lung cancer cells

Human cancers often re-express germline factors, yet their mechanistic role in oncogenesis and cancer progression remains unknown. Here we demonstrate that DEAD-box helicase 4 (DDX4), a germline factor and RNA helicase conserved in all multicellular organisms, contributes to increased cell motility and cisplatin-mediated drug resistance in small cell lung cancer (SCLC) cells. Proteomic analysis suggests that DDX4 expression upregulates proteins related to DNA repair and immune/inflammatory response. Consistent with these trends in cell lines, DDX4 depletion compromised in vivo tumor development while its overexpression enhanced tumor growth even after cisplatin treatment in nude mice. Further, the relatively higher DDX4 expression in SCLC patients correlates with decreased survival and shows increased expression of immune/inflammatory response markers. Taken together, we propose that DDX4 increases SCLC cell survival, by increasing the DNA damage and immune response pathways, especially under challenging conditions such as cisplatin treatment.

Rb Tumor Suppressor in Small Cell Lung Cancer: Combined Genomic and IHC Analysis with a Description of a Distinct Rb-Proficient Subset

PURPOSE

RB1 mutations and loss of retinoblastoma (Rb) expression represent consistent but not entirely invariable hallmarks of small cell lung cancer (SCLC). The prevalence and characteristics of SCLC retaining wild-type Rb are not well-established. Furthermore, the performance of targeted next-generation sequencing (NGS) versus immunohistochemistry for Rb assessment is not well-defined.

EXPERIMENTAL DESIGN

A total of 208 clinical SCLC samples were analyzed by comprehensive targeted NGS, covering all exons of RB1, and Rb IHC. On the basis of established coordination of Rb/p16/cyclinD1 expression, p16-high/cyclinD1-low profile was used as a marker of constitutive Rb deficiency.

RESULTS

Fourteen of 208 (6%) SCLC expressed wild-type Rb, accompanied by a unique p16-low/cyclinD1-high profile supporting Rb proficiency. Rb-proficient SCLC was associated with neuroendocrine-low phenotype, combined SCLC with non-SCLC (NSCLC) histology and aggressive behavior. These tumors exclusively harbored CCND1 amplification (29%), and were markedly enriched in CDKN2A mutations (50%) and NSCLC-type alterations (KEAP1, STK11, FGFR1). The remaining 194 of 208 SCLC were Rb-deficient (p16-high/cyclinD1-low), including 184 cases with Rb loss (of which 29% lacked detectable RB1 alterations by clinical NGS pipeline), and 10 cases with mutated but expressed Rb.

CONCLUSIONS

This is the largest study to date to concurrently analyze Rb by NGS and IHC in SCLC, identifying a 6% rate of Rb proficiency. Pathologic-genomic data implicate NSCLC-related progenitors as a putative source of Rb-proficient SCLC. Consistent upstream Rb inactivation via CDKN2A/p16↓ and CCND1/cyclinD1↑ suggests the potential utility of CDK4/6 inhibitors in this aggressive SCLC subset. The study also clarifies technical aspects of Rb status determination in clinical practice, highlighting the limitations of exon-only sequencing for RB1 interrogation. See related commentary by Mahadevan and Sholl, p. 4603.

PFKFB3 regulates cancer stemness through the hippo pathway in small cell lung carcinoma

PFKFB3 (6-phosphofructo-2-kinase) is the rate-limiting enzyme of glycolysis and is overexpressed in several human cancers that are associated with poor prognosis. High PFKFB3 expression in cancer stem cells promotes glycolysis and survival in the tumor microenvironment. Inhibition of PFKFB3 by the glycolytic inhibitor PFK158 and by shRNA stable knockdown in small cell lung carcinoma (SCLC) cell lines inhibited glycolysis, proliferation, spheroid formation, and the expression of cancer stem cell markers CD133, Aldh1, CD44, Sox2, and ABCG2. These factors are also associated with chemotherapy resistance. We found that PFK158 treatment and PFKFB3 knockdown enhanced the ABCG2-interacting drugs doxorubicin, etoposide, and 5-fluorouracil in reducing cell viability under conditions of enriched cancer stem cells (CSC). Additionally, PFKFB3 inhibition attenuated the invasion/migration of SCLC cells by downregulating YAP/TAZ signaling while increasing pLATS1 via activation of pMST1 and NF2 and by reducing the mesenchymal protein expression. PFKFB3 knockdown and PFK158 treatment in a H1048 SCLC cancer stem cell-enriched mouse xenograft model showed significant reduction in tumor growth and weight with reduced expression of cancer stem cell markers, ABCG2, and YAP/TAZ. Our findings identify that PFKFB3 is a novel target to regulate cancer stem cells and its associated therapeutic resistance markers YAP/TAZ and ABCG2 in SCLC models.

New PET Tracers: Current Knowledge and Perspectives in Lung Cancer

PET/CT with the tracer 2-[¹⁸F]fluoro-2-deoxy-D-glucose ([¹⁸F]FDG) has improved diagnostic imaging in cancer and is routinely used for diagnosing, staging and treatment planning in lung cancer patients. However, pitfalls of [¹⁸F]FDG-PET/CT limit the use in specific settings. Additionally, lung cancer is still the leading cause of cancer associated death and has high risk of recurrence after curative treatment. These circumstances have led to the continuous search for more sensitive and specific PET tracers to optimize lung cancer diagnosis, staging, treatment planning and evaluation. The objective of this review is to present and discuss current knowledge and perspectives of new PET tracers for use in lung cancer. A literature search was performed on PubMed and clinicaltrials.gov, limited to the past decade, excluding case reports, preclinical studies and studies on established tracers such as [¹⁸F]FDG and DOTATE. The most relevant papers from the search were evaluated. Several tracers have been developed targeting specific tumor characteristics and hallmarks of cancer. A small number of tracers have been studied extensively and evaluated head-to-head with [¹⁸F]FDG-PET/CT, whereas others need further investigation and validation in larger clinical trials. At this moment, none of the tracers can replace [¹⁸F]FDG-PET/CT. However, they might serve as supplementary imaging methods to provide more knowledge about biological tumor characteristics and visualize intra- and inter-tumoral heterogeneity.

Identification of sSIGLEC5 and sLAG3 as New Relapse Predictors in Lung Cancer

Lung cancer (LC) continues to be the leading cause of cancer-related deaths in both men and women worldwide. After complete tumour resection, around half of the patients suffer from disease relapse, emphasising the critical need for robust relapse predictors in this disease. In search of such biomarkers, 83 patients with non-microcytic lung cancer and 67 healthy volunteers were studied. Pre-operative levels of sSIGLEC5 along with other soluble immune-checkpoints were measured and correlated with their clinical outcome. Soluble SIGLEC5 (sSIGLEC5) levels were higher in plasma from patients with LC compared with healthy volunteers. Looking into those patients who suffered relapse, sSIGLEC5 and sLAG3 were found to be strong relapse predictors. Following a binary logistic regression model, a sSIGLEC5 + sLAG3 score was established for disease relapse prediction (area under the curve 0.8803, 95% confidence intervals 0.7955−0.9652, cut-off > 2.782) in these patients. Based on score cut-off, a Kaplan−Meier analysis showed that patients with high sSIGLEC5 + sLAG3 score had significantly shorter relapse-free survival (p ≤ 0.0001) than those with low sSIGLEC5 + sLAG3 score.Our study suggests that pre-operative sSIGLEC5 + sLAG3 score is a robust relapse predictor in LC patients.

Antibody-Drug Conjugate Targeting c-Kit for the Treatment of Small Cell Lung Cancer

Lung cancer is the leading cause of cancer-related deaths. Small cell lung cancer (SCLC) accounts for 15–25% of all lung cancers. It exhibits a rapid doubling time and a high degree of invasiveness. Additionally, overexpression of c-Kit occurs in 70% of SCLC patients. In this study, we evaluated an antibody-drug conjugate (ADC) that targets c-Kit, which is a potential therapeutic agent for SCLC. First, we generated and characterized 4C9, a fully human antibody that targets c-Kit and specifically binds to SCLC cells expressing c-Kit with a binding affinity of K_D = 5.5 × 10⁻⁹ M. Then, we developed an ADC using DM1, a microtubule inhibitor, as a payload. 4C9-DM1 efficiently induced apoptosis in SCLC with an IC₅₀ ranging from 158 pM to 4 nM. An in vivo assay using a xenograft mouse model revealed a tumor growth inhibition (TGI) rate of 45% (3 mg/kg) and 59% (5 mg/kg) for 4C9-DM1 alone. Combination treatment with 4C9-DM1 plus carboplatin/etoposide or lurbinectedin resulted in a TGI rate greater than 90% compared with the vehicle control. Taken together, these results indicate that 4C9-DM1 is a potential therapeutic agent for SCLC treatment.

A radioenhancing nanoparticle mediated immunoradiation improves survival and generates long-term antitumor immune memory in an anti-PD1-resistant murine lung cancer model

Background

Combining radiotherapy with PD1 blockade has had impressive antitumor effects in preclinical models of metastatic lung cancer, although anti-PD1 resistance remains problematic. Here, we report results from a triple-combination therapy in which NBTXR3, a clinically approved nanoparticle radioenhancer, is combined with high-dose radiation (HDXRT) to a primary tumor plus low-dose radiation (LDXRT) to a secondary tumor along with checkpoint blockade in a mouse model of anti-PD1-resistant metastatic lung cancer.

Methods

Mice were inoculated with 344SQR cells in the right legs on day 0 (primary tumor) and the left legs on day 3 (secondary tumor). Immune checkpoint inhibitors (ICIs), including anti-PD1 (200 μg) and anti-CTLA4 (100 μg) were given intraperitoneally. Primary tumors were injected with NBTXR3 on day 6 and irradiated with 12-Gy (HDXRT) on days 7, 8, and 9; secondary tumors were irradiated with 1-Gy (LDXRT) on days 12 and 13. The survivor mice at day 178 were rechallenged with 344SQR cells and tumor growth monitored thereafter.

Results

NBTXR3  +  HDXRT  +  LDXRT  +  ICIs had significant antitumor effects against both primary and secondary tumors, improving the survival rate from 0 to 50%. Immune profiling of the secondary tumors revealed that NBTXR3  +  HDXRT  +  LDXRT increased CD8 T-cell infiltration and decreased the number of regulatory T (Treg) cells. Finally, none of the re-challenged mice developed tumors, and they had higher percentages of CD4 memory T cells and CD4 and CD8 T cells in both blood and spleen relative to untreated mice.

Conclusions

NBTXR3 nanoparticle in combination with radioimmunotherapy significantly improves anti-PD1 resistant lung tumor control via promoting antitumor immune response.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-01163-1.

Prophylactic cranial irradiation (PCI), hippocampal avoidance (HA) whole brain radiotherapy (WBRT) and stereotactic radiosurgery (SRS) in small cell lung cancer (SCLC): Where do we stand?

Small cell lung cancer (SCLC) is an aggressive form of lung cancer associated with an increased risk of develping brain metastases (BM), which are a significant cause of morbidity and mortality. Prophylactic cranial irradiation (PCI) was first introduced in the 1970s with the aim of reducing BM incidence and improving survival and quality of life (QoL). Prospective clinical trials and meta-analyses have demonstrated its effectiveness in reducing BM incidence and improving survival, across all stages of the disease following response to induction chemotherapy. Despite its long history, "unknowns" surrounding PCI use still exist and there are particular subgroups of patients for which its use remains controversial. PCI is known to cause neurocognitive toxicity which can have a significant impact on a patient's QoL. Strategies to minimise this, including the use of hippocampal avoidance radiotherapy techniques, neuroprotective drugs and stereotactic radiosurgery in place of whole brain radiotherapy for the treatment of BM, are under evaluation. This review offers a summary of the key PCI trials published to date and the current treatment recommendations based on available evidence. It also discusses the key questions being addressed in ongoing clinical trials and highlights others where there is currently a knowledge gap and therefore where further data are urgently required.

Therapeutic approaches and outcomes in patients with larynx or hypopharynx high-grade neuroendocrine carcinoma: A single-center retrospective analysis

BACKGROUND

High-grade neuroendocrine carcinoma of the larynx (HG-NECL) is rare and aggressive with limited data regarding response to systemic therapy. We evaluated clinicopathological features, therapeutic approaches, and outcomes in patients with laryngeal or hypopharyngeal HG-NECL.

METHODS

Data were retrospectively collected through 1997-2020. Median disease-free (mDFS), progression-free (mPFS), and overall survival (mOS) were estimated using the Kaplan-Meier method.

RESULTS

Fifteen patients were identified; most had locoregional (N = 7) or metastatic disease (N = 5). The main curative-intent treatment was chemoradiation concurrent with platinum-based chemotherapy; the rate of complete response was 78%. Most patients (80%) developed recurrence; the mDFS was 13.1 months. For the first-line palliative therapy, the ORR and mPFS were 50% and 3.1 months, respectively. For all patients, the mOS was 17.8 months, and 8.6 months for metastatic disease.

CONCLUSION

Laryngeal HG-NEC is associated with high relapse rates and dismal prognosis for those with recurrent/metastatic disease. Novel therapeutic strategies are needed.

Reactivation of dormant tumor cells by modified lipids derived from stress-activated neutrophils

Tumor recurrence years after seemingly successful treatment of primary tumors is one of the major causes of mortality in patients with cancer. Reactivation of dormant tumor cells is largely responsible for this phenomenon. Using dormancy models of lung and ovarian cancer, we found a specific mechanism, mediated by stress and neutrophils, that may govern this process. Stress hormones cause rapid release of proinflammatory S100A8/A9 proteins by neutrophils. S100A8/A9 induce activation of myeloperoxidase, resulting in accumulation of oxidized lipids in these cells. Upon release from neutrophils, these lipids up-regulate the fibroblast growth factor pathway in tumor cells, causing tumor cell exit from the dormancy and formation of new tumor lesions. Higher serum concentrations of S100A8/A9 were associated with shorter time to recurrence in patients with lung cancer after complete tumor resection. Targeting of S100A8/A9 or β2-adrenergic receptors abrogated stress-induced reactivation of dormant tumor cells. These observations demonstrate a mechanism linking stress and specific neutrophil activation with early recurrence in cancer.

Molecular profiles of small cell lung cancer subtypes: therapeutic implications

Small cell lung cancer (SCLC; accounting for approximately 13%-15% of all lung cancers) is an exceptionally lethal malignancy characterized by rapid doubling time and high propensity to metastasize. In contrast to the increasingly personalized therapies in other types of lung cancer, SCLC is still regarded as a homogeneous disease and the prognosis of SCLC patients remains poor. Recently, however, substantial progress has been made in our understanding of SCLC biology. Advances in genomics and development of new preclinical models have facilitated insights into the intratumoral heterogeneity and specific genetic alterations of this disease. This worldwide resurgence of studies on SCLC has ultimately led to the development of novel subtype-specific classifications primarily based on the neuroendocrine features and distinct molecular profiles of SCLC. Importantly, these biologically distinct subtypes might define unique therapeutic vulnerabilities. Herein, we summarize the current knowledge on the molecular profiles of SCLC subtypes with a focus on their potential clinical implications.

Myelopreservation with Trilaciclib in Patients Receiving Topotecan for Small Cell Lung Cancer: Results from a Randomized, Double-Blind, Placebo-Controlled Phase II Study

INTRODUCTION

Multilineage myelosuppression is an acute toxicity of cytotoxic chemotherapy, resulting in serious complications and dose modifications. Current therapies are lineage specific and administered after chemotherapy damage has occurred. Trilaciclib is a cyclin-dependent kinase 4/6 inhibitor that is administered prior to chemotherapy to preserve hematopoietic stem and progenitor cells and immune system function during chemotherapy (myelopreservation).

METHODS

In this randomized, double-blind, placebo-controlled phase II trial, patients with previously treated extensive-stage small cell lung cancer (ES-SCLC) were randomized to receive intravenous trilaciclib 240 mg/m2 or placebo before topotecan 1.5 mg/m2 on days 1-5 of each 21-day cycle. Primary endpoints were duration of severe neutropenia (DSN) in cycle 1 and occurrence of severe neutropenia (SN). Additional endpoints were prespecified to further assess the effect of trilaciclib on myelopreservation, safety, patient-reported outcomes (PROs), and antitumor efficacy.

RESULTS

Thirty-two patients received trilaciclib, and 29 patients received placebo. Compared with placebo, administration of trilaciclib prior to topotecan resulted in statistically significant and clinically meaningful decreases in DSN in cycle 1 (mean [standard deviation] 2 [3.9] versus 7 [6.2] days; adjusted one-sided P < 0.0001) and occurrence of SN (40.6% versus 75.9%; adjusted one-sided P = 0.016), with numerical improvements in additional neutrophil, red blood cell, and platelet measures. Patients receiving trilaciclib had fewer grade ≥ 3 hematologic adverse events than patients receiving placebo, particularly neutropenia (75.0% versus 85.7%) and anemia (28.1% versus 60.7%). Myelopreservation benefits extended to improvements in PROs, specifically in those related to fatigue. Antitumor efficacy was comparable between treatment arms.

CONCLUSIONS

Compared with placebo, the addition of trilaciclib prior to topotecan for the treatment of patients with previously treated ES-SCLC improves the patient experience of receiving chemotherapy, as demonstrated by a reduction in chemotherapy-induced myelosuppression, improved safety profile, improved quality of life and no detrimental effects on antitumor efficacy.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02514447.

FDA Approval Summary: Lurbinectedin for the Treatment of Metastatic Small Cell Lung Cancer

On June 15, 2020, the FDA granted accelerated approval to lurbinectedin for the treatment of adult patients with metastatic small cell lung cancer (SCLC) with disease progression on or after platinum-based chemotherapy. Approval was granted on the basis of the clinically meaningful effects on overall response rate (ORR) and duration of response (DOR), and the safety profile observed in a multicenter, open-label, multicohort clinical trial (PM1183-B-005-14, NCT02454972), referred to as Study B-005, in patients with advanced solid tumors. The trial included a cohort of 105 patients with metastatic SCLC who had disease progression on or after platinum-based chemotherapy. The confirmed ORR determined by investigator assessment using RECIST 1.1 in the approved SCLC patient population was 35% [95% confidence interval (CI): 26-45], with a median DOR of 5.3 (95% CI: 4.1-6.4) months. The drug label includes warnings and precautions for myelosuppression, hepatotoxicity, and embryo-fetal toxicity. This is the first drug approved by the FDA in over 20 years in the second line for patients with metastatic SCLC. Importantly, this approval includes an indication for patients who have platinum-resistant disease, representing an area of particular unmet need.

Prognostic significance of serum osteopontin levels in small cell lung cancer

BACKGROUND

Osteopontin (OPN) is closely related to tumor occurrence and metastasis. This study explored the clinical value of serum OPN levels in small cell lung cancer (SCLC) patients.

METHODS

The ELISA method was used to determine the OPN level of 96 SCLC patients before and after first-line chemotherapy, and compared with 60 healthy controls.

RESULTS

The serum OPN level of SCLC patients before treatment was significantly higher than that of the healthy control (P < 0.001). Serum OPN levels were related to disease stage, tumor size, and lymph node metastasis (P = 0.012, 0.034, and 0.037, respectively). Serum OPN level decreased after first-line chemotherapy (P = 0.019), which was related to treatment response (P = 0.011). The serum OPN level was an independent predictor of overall survival.

CONCLUSIONS

The serum OPN level can be used as a biomarker to predict treatment response and survival of SCLC patients.

Emerging drugs for small cell lung cancer: a focused review on immune checkpoint inhibitors

INTRODUCTION

Small cell lung cancer (SCLC) is an aggressive malignancy that accounts for 15% of all lung cancers. It is characterized by initial responsiveness to therapy followed by rapid disease progression that is relatively resistant to further treatment. Recently, the addition of an immune checkpoint inhibitor (ICI) to chemotherapy has improved survival in patients with advanced disease, the first advance in systemic therapy in SCLC in over 30 years.

AREAS COVERED

In this review, we present an overview of SCLC with a focus on the scope of the problem and standard treatment, followed by a critical assessment of scientific rationale for immunotherapy in SCLC and the clinical trials that have been performed with ICIs in SCLC. Finally, we address ongoing hurdles for the development of ICIs in SCLC and potential avenues for further study.

EXPERT OPINION

Despite solid biological rationale, the results of clinical trials of ICIs in SCLC have yielded modest benefits. A small subset of patients does achieve long-term benefit, but further development of ICIs in SCLC will depend on the identification of predictive biomarkers and the design of combination regimens that take advantage of the molecular alterations that drive the immune-avoidance mechanisms and survival of SCLC cells.

Prognostic factors and outcome of reirradiation for locally recurrent small cell lung cancer-a multicenter study

Background

The prognosis of patients with recurrent small cell lung cancer (SCLC) remains poor and treatment options are limited. We performed a multi-institution retrospective cohort study to evaluate the outcome of thoracic reirradiation, identify prognostic factors and assess treatment-related toxicity.

Methods

Data of 33 patients re-irradiated for recurrent SCLC at 4 international university hospitals, were analysed. Overall survival (OS) acute and late toxicities were evaluated and prognostic factors for reirradiation were identified.

Results

Reirradiation (Re-RT) was performed at a median interval time of 24 months after the first thoracic radiotherapy series. Median survival after reirradiation was 7 months (range, 1-54 months). The Re-RT dose in EQD2 ranged from 20 to 87.50 Gy with a median of 32.50 Gy. The 1- and 2-year OS were 33% and 17%, respectively. Patients with a good performance status (KPS >70%), absence of extrathoracic disease, reirradiation dose (EQD2) of >40 Gy and a cumulative dose of first plus second series of radiotherapy (EQD2) >90 Gy were associated with improved OS. Acute pulmonary Grade 1-2 toxicity from re-irradiation was recorded in 11 patients (33%) and grade 3 acute toxicity was encountered 1 patient (3%).

Conclusions

Reirradiation for locoregionally recurrent SCLC is safe and shows promising outcomes. Patients reirradiated with doses >40 Gy experienced more favourable survival rates. In contrast, patients with a poor performance status or extrathoracic disease have a poor prognosis and Re-RT should be considered only for symptom control in this group.

SEOM clinical guidelines for the treatment of small-cell lung cancer (SCLC) (2019)

Small-cell lung cancer (SCLC) accounts for 15% of lung cancers. Only one-third of patients are diagnosed at limited stage. The median survival remains to be around 15–20 months without significative changes in the strategies of treatment for many years. In stage I and IIA, the standard treatment is the surgery followed by adjuvant therapy with platinum–etoposide. In stage IIB–IIIC, the recommended treatment is early concurrent chemotherapy with platinum–etoposide plus thoracic radiotherapy followed by prophylactic cranial irradiation in patients without progression. However, in the extensive stage, significant advances have been observed adding immunotherapy to platinum–etoposide chemotherapy to obtain a significant increase in overall survival, constituting the new recommended standard of care. In the second-line treatment, topotecan remains as the standard treatment. Reinduction with platinum–etoposide is the recommended regimen in patients with sensitive relapse (≥ 3 months) and new drugs such as lurbinectedin and immunotherapy are new treatment options. New biomarkers and new clinical trials designed according to the new classification of SCLC subtypes defined by distinct gene expression profiles are necessary.

Surgery as a Potential Treatment Option for Patients With Stage III Small-Cell Lung Cancer: A Propensity Score Matching Analysis

Surgery is commonly recommended for patients with stage I small-cell lung cancer (SCLC), whereas chemotherapy and radiotherapy are considered the standard treatment for patients with stage III SCLC. However, recent studies have suggested that a small proportion of patients with SCLC at an advanced stage may benefit from surgical resection. Therefore, in this study, we investigated the effectiveness of surgery in patients with stage III SCLC. Patients were selected from the Surveillance, Epidemiology, and End Results (SEER) database between 2004 and 2013. Propensity score matching (PSM) was used to eliminate any clinical bias. The overall survival (OS) was determined using the Kaplan–Meier method and compared using the log-rank test. The Cox proportional-hazards model was used to identify the effect of surgery on the OS. Of 9606 patients with stage III SCLC, 234 underwent surgery. Compared with the non-surgical group, a higher proportion of patients undergoing surgery had T1 and N0-N1 disease (risen by 10.7% for T1; 12.6% for N0-N1) and a lower proportion had T4 and N3 disease (decreased by 14.3% for T4; 12.5% for N3). The Kaplan-Meier analysis showed that patients who underwent surgery had a better OS before and after PSM. The multivariate analysis showed that surgery was beneficial for patients with stage III SCLC (HR: 0.651, 95% CI 0.524–0.808, P < 0.001). In conclusion, surgical resection might be associated with improved OS for patients with stage III SCLC and may be considered for the treatment of these patients. Further prospective studies are required to confirm these findings.

Prognostic value of tumor cavitation in extensive-stage small-cell lung cancer patients treated with anlotinib

PURPOSE

Anlotinib is a novel multi-target tyrosine kinase inhibitor (TKI) for tumor angiogenesis and tumor cell proliferation. The efficacy of anlotinib as a third-line or beyond therapy for SCLC was confirmed in the ALTER1202 trial. For lung cancer patients treated with antiangiogenesis agents, the phenomenon of cavitation is commonly seen in the lung target lesions. The impact of tumor cavitation on survival in lung cancer patients treated with vascular-targeted therapy remains controversial. Our retrospective study was to investigate the prognostic value of tumor cavitation in extensive-stage SCLC patients treated with anlotinib.

METHODS

A total of 73 extensive-stage SCLC patients confirmed by histopathology from January 2018 to January 2019 were retrospectively analyzed. All patients received anlotinib therapy at Shanghai Chest Hospital. We defined tumor cavitation of the lung target lesions as that part of solid component was changed to air-filled area according to chest CT. Progression-free survival (PFS) was calculated from the beginning of anlotinib therapy to the disease progression or the last follow-up visit.

RESULTS

Eleven (15.0%) patients had tumor cavitation during anlotinib therapy. The ORR of the 73 patients was 15.1%. Multivariate logistic regression analysis showed that tumor cavitation during anlotinib therapy was not associated with gender (P = 0.630), age (P = 0.190), smoking status (P = 0.165), anatomy type (P = 0.641), and the line of anlotinib therapy (P = 0.302). The median PFS of all patients was 2.6 months (95%CI 2.1-3.2). According to the univariate analysis, the median PFS in patients with and without tumor cavitation was 5.0 months and 2.2 months, respectively, and the difference was statistically significant (P = 0.041). According to the multivariate analysis, tumor cavitation was an independent factor for PFS after adjusting gender, age, smoking status, anatomy type, the line of anlotinib therapy, tumor cavitation, and response to anlotinib (adjusted HR 0.316, 95%CI 0.142-0.702; P = 0.005).

CONCLUSIONS

In 73 extensive-stage SCLC patients treated with anlotinib, no demographic/clinical characteristic was related to tumor cavitation, and tumor cavitation was an independent factor in predicting better PFS.

A phase I study of weekly doxorubicin and oral topotecan for patients with relapsed or refractory small cell lung cancer (SCLC): A Fred and Pamela Buffet Cancer Center Clinical Trials Network study

BACKGROUND

Relapsed/refractory small cell lung cancer (SCLC) has a poor prognosis, with no good options. We evaluated a novel combination of topotecan and doxorubicin, providing sequential topoisomerase I and II inhibition, in this setting.

MATERIALS AND METHODS

Adult patients (>19 years) with relapsed/refractory SCLC, who had received at least one prior chemotherapy regimen were eligible. Patients received escalating doses of oral topotecan on days 1-5 of each three week cycle (maximum - 5 cycles). The dosing cohorts were: 0.85 mg/m², 1.05 mg/m², 1.35 mg/m², 1.65 mg/m² and 2.30 mg/m². All patients received weekly doxorubicin 20 mg/m² intravenously starting day 6 of the first cycle and continued weekly for a maximum of 15 weeks. In the absence of pre-specified dose limiting toxicities (DLT), patients were enrolled serially to escalated dose level cohorts.

RESULTS

Twenty-two patients were enrolled, of which 20 were evaluable. Median age was 61 years; 74% were male and 95% were Caucasian. Hematologic side effects were the most common adverse events. There were no therapy-related Grade 5 toxicities. Incidence of DLT based on cohorts were: DL2: 1/6 (Grade 4 thrombocytopenia), DL3: 1/6 (AST elevation) and DL4: 2/4 (Grade 4 thrombocytopenia). Response rate was 20% (4/20) and disease control rate (SD + PR) was 36%. The median progression free and overall survival were 3.6 months and 6 months, respectively.

CONCLUSIONS

The combination of topotecan and doxorubicin was safe and effective in relapsed/refractory SCLC. The maximum tolerated dose of oral topotecan was 1.35 mg/m² when given concurrently with weekly doxorubicin.

Prognostic significance of serum soluble DR5 levels in small-cell lung cancer

The death receptor 5 (DR5) is a member of the tumor necrosis factor receptor superfamily that can transduce the apoptosis signal in cells. This study assessed serum levels of soluble death receptor 5 (sDR5) in small-cell lung cancer (SCLC) patients compared with those in healthy controls. Clinicopathological features of patients, treatment responses, and overall survival of patients were also recorded and analyzed. The sDR5 levels were analyzed using ELISA in 50 healthy controls and 82 SCLC patients before and after first-line chemotherapy. The statistical data showed that pre-treatment levels of serum sDR5 in SCLC patients were higher than those of healthy controls (P<0.001). Pre-treatment levels of serum sDR5 were significantly associated with smoking history of patients, Veterans Administration Lung Study Group (VALSG) stage, tumor size, and lymph node (N) metastasis (P=0.028, 0.001, 0.028, and 0.01, respectively). After treatment with the first-line chemotherapy, the post-treatment levels of serum sDR5 were obviously decreased (P<0.001), and correlated with treatment responses (P<0.001), although there was no significant difference in their pretreatment sDR5 levels (P=0.62). Cox proportional hazard analysis demonstrated that the post-treatment levels of serum sDR5, VALSG stage, and PS status were all independent predictors for overall survival of patients. The results from the current study indicate that serum level of sDR5 could be further confirmed as a biomarker to predict treatment responses and survival of SCLC patients.