Atezolizumab Plus Carboplatin and Etoposide in Patients with Untreated Extensive-Stage Small-Cell Lung Cancer: Interim Results of the MAURIS Phase IIIb Trial

Effect of the number of induction chemotherapy cycles on the efficacy of first-line atezolizumab combined with chemotherapy in extensive-stage small cell lung cancer

Background

Compared with chemotherapy alone, the addition of atezolizumab to the first-line treatment of extensive-stage small cell lung cancer (ES-SCLC) improves the overall survival (OS), but the benefit remains limited. This study aims at investigating the factors influencing prognosis and to assess the effect of the number of induction chemotherapy cycles on treatment efficacy.

Methods

We retrospectively analyzed the data of patients with ES-SCLC treated in five centers between March 2020 and September 2022. All 45 patients received first-line treatment with etoposide plus platinum combined with atezolizumab. The primary endpoints were progression-free survival (PFS) and OS in the total population and subpopulations based on the number of induction chemotherapy cycles. Least absolute shrinkage and selection operator (LASSO) regression were applied to identify the prognostic variables, and the effect of varying the number of induction chemotherapy cycles on the treatment efficacy was evaluated.

Results

A total of 45 patients were enrolled in the study. The median PFS for the first-line treatment was 7 months, and the median OS was 17.6 months. The following 10 variables were analyzed using LASSO regression: gender, age, liver metastasis, bone metastasis, brain metastasis, number of first-line induction chemotherapy cycles, first-line immunotherapy maintenance, receipt of cross-line immunotherapy, chest radiotherapy, and brain radiotherapy. The analysis revealed that receiving ≥6 cycles of induction chemotherapy was the most important variable affecting prognosis and the only one significant [concordance index: 0.658; hazard ratio: 0.32 (95% confidence interval: 0.17-0.63)]. Patients who received ≥6 cycles of induction chemotherapy (n=25) had a longer median PFS (8 vs. 5 months) and median OS (18.5 vs. 13.1 months) than those who received <6 cycles (n=20). Subgroup analyses indicated consistent survival benefits of ≥6 induction chemotherapy cycles across key subgroups, including males, patients aged ≤65 years, and those with or without brain metastasis (all P value <0.05).

Conclusions

Receiving ≥6 cycles of induction chemotherapy significantly prolonged the median PFS and median OS of patients, highlighting its crucial factor influencing the efficacy of first-line atezolizumab combined with chemotherapy in patients with ES-SCLC.

Benefit of Consolidation Thoracic Radiotherapy in Extensive-Stage Small-Cell Lung Cancer Patients Treated with Immunotherapy: Data from Slovenian Cohort

Chemoimmunotherapy (CT/IO) with immune checkpoint inhibitors has recently become the standard of care for extensive-stage small cell lung cancer (ES-SCLC). Given the uncertain role of consolidation thoracic radiotherapy (cTRT) in this setting, we conducted a real-world study to evaluate the efficacy and safety of cTRT in ES-SCLC patients receiving first-line CT/IO. We performed a retrospective analysis of ES-SCLC patients treated with first-line CT/IO in Slovenia from December 2019 to June 2024. Patient characteristics, treatment patterns, survival outcomes, and adverse events were analyzed, with subgroup comparisons based on cTRT administration. Among 208 patients (median age: 66 years), median overall survival was 12.1 months (95% CI: 10.6-13.7). cTRT was administered to 46 patients (22.1%), who had fewer metastases. cTRT was associated with improved OS (17.0 vs. 10.8 months; p < 0.001) and was an independent OS predictor (HR = 0.58, p = 0.035). Grade ≥ 3 adverse events were similar (26.1% vs. 21.3%), though pneumonitis occurred more frequently with cTRT (6.5% vs. 0%, p = 0.001). cTRT may improve survival in ES-SCLC patients treated with CT/IO, with no significant increase in toxicity apart from pneumonitis. Further prospective studies are needed.

Real-world evidence in extensive disease small cell lung cancer: The missing piece of the puzzle

Small cell lung cancer (SCLC) is a highly aggressive disease, often diagnosed at an advanced stage and with limited treatment options. In recent years, immunotherapy has been approved in combination with chemotherapy in the first line setting of extensive stage disease (ES-SCLC). However, only 10-15 % of patients with ES-SCLC treated with chemoimmunotherapy (CT-IO) experience a long-term benefit. In addition, patients are often clinically frail due to advanced age, comorbidities, and disease-related symptoms, making SCLC a challenging condition. Real-world evidence (RWE) becomes particularly valuable in this scenario, not only to confirm the results of pivotal trials, but also to evaluate the outcomes of CT-IO in populations that are generally excluded from clinical trials. RWE could also define the role of integrative treatments such as thoracic consolidation radiotherapy and prophylactic cranial irradiation, which are used in selected patients in the clinical practice but were scarcely applied in pivotal trials. In this review, we focused on RWE in ES-SCLC, with the aim of improving clinical decision making. Notably, real-world data have largely confirmed the efficacy and safety of CT-IO observed in pivotal clinical trials, with a possible benefit even in more fragile patients. However, these studies also highlight that a significant proportion of the ES-SCLC population remains untreated due to poor clinical conditions.

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

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

Emerging therapeutic frontiers in cancer: insights into posttranslational modifications of PD-1/PD-L1 and regulatory pathways

The interaction between programmed cell death ligand 1 (PD-L1), which is expressed on the surface of tumor cells, and programmed cell death 1 (PD-1), which is expressed on T cells, impedes the effective activation of tumor antigen-specific T cells, resulting in the evasion of tumor cells from immune-mediated killing. Blocking the PD-1/PD-L1 signaling pathway has been shown to be effective in preventing tumor immune evasion. PD-1/PD-L1 blocking antibodies have garnered significant attention in recent years within the field of tumor treatments, given the aforementioned mechanism. Furthermore, clinical research has substantiated the efficacy and safety of this immunotherapy across various tumors, offering renewed optimism for patients. However, challenges persist in anti-PD-1/PD-L1 therapies, marked by limited indications and the emergence of drug resistance. Consequently, identifying additional regulatory pathways and molecules associated with PD-1/PD-L1 and implementing judicious combined treatments are imperative for addressing the intricacies of tumor immune mechanisms. This review briefly outlines the structure of the PD-1/PD-L1 molecule, emphasizing the posttranslational modification regulatory mechanisms and related targets. Additionally, a comprehensive overview on the clinical research landscape concerning PD-1/PD-L1 post-translational modifications combined with PD-1/PD-L1 blocking antibodies to enhance outcomes for a broader spectrum of patients is presented based on foundational research.