Atezolizumab combined with chemotherapy in the first-line treatment of extensive-stage small cell lung cancer: a real-life data of the Turkish Oncology Group

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.

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

BACKGROUND

MAURIS is an Italian multicenter, open-label, phase IIIb ongoing trial, aiming at evaluating the safety and effectiveness of atezolizumab + carboplatin/etoposide in patients with newly diagnosed, extensive-stage small-cell lung cancer (ES-SCLC). The primary objective is the safety evaluation.

MATERIALS AND METHODS

Patients received atezolizumab + carboplatin/etoposide Q3W for 4-6 cycles in the induction phase, followed by atezolizumab maintenance Q3W. We presented the interim analysis on safety (referring to the induction phase) and clinical effectiveness, in all patients (N = 154) and in subgroups that received ≤3 (N = 23), 4 (N = 43), and 5-6 cycles (N = 89) of induction.

RESULTS

At a median follow-up of 10.5 months, 139 patients (90.3%) discontinued treatment. Serious adverse events occurred in 29.9% of patients overall, and the rate was lower in patients with 5-6 cycles (19.1%) than in those with 4 (34.9%) or ≤3 (63.6%) cycles. Immune-mediated adverse events were reported in 14.9%, 15.7%, 11.6%, and 18.2% of patients, overall and by subgroup, respectively. The median overall survival and progression-free survival were 10.7 and 5.5 months, respectively. Overall, 111 patients (71.6%) had a tumor response.

CONCLUSIONS

Interim results provide further evidences about safety and efficacy profile of atezolizumab + carboplatin/etoposide treatment in a ES-SCLC patient population closer to that observed in clinical practice.

CLINICAL TRIAL REGISTRATION

Eudract No. 2019-001146-17, NCT04028050.

Evaluation of Real-Life Chemoimmunotherapy Combination in Patients with Metastatic Small Cell Lung Carcinoma (SCLC): A Multicentric Case-Control Study

The current first-line standard treatment for advanced small cell lung cancer (SCLC) is a combination of chemotherapy and immunotherapy. However, few efficacy data are available in a real-life settings, including frail patients. The aim of this study is to describe the real-life efficacy of chemoimmunotherapy in an unselected SCLC population. We conducted a retrospective multicenter study, which compared two cohorts of patients with treatment-naive metastatic SCLC treated in six academic centers in the Greater Paris area. Cohort 1 included patients treated with chemotherapy between January 2017 and December 2018, and cohort 2 included patients treated with chemoimmunotherapy between January 2019 and December 2020. A total of 153 consecutive patients were included (cohort 1: n = 96; cohort 2: n = 57). Clinical characteristics were similar between the two cohorts. Overall survival (OS) was statistically higher in cohort 2 (median survival 15.47 months) than in cohort 1 (median survival 9.5 months) (p = 0.0001). OS for patients with a performance status ≥2 and for patients ≥70 years old was not statistically different between the two cohorts. Chemoimmunotherapy efficacy was better compared to chemotherapy alone in case of brain or liver metastases. In conclusion, the combination of chemoimmunotherapy in metastatic SCLC appears to provide a real-life OS benefit. Dedicated clinical trials are needed to test this strategy in patients with impaired performance status or advanced age.

PD-1/PD-L1 and DNA Damage Response in Cancer

The application of immunotherapy for cancer treatment is rapidly becoming more widespread. Immunotherapeutic agents are frequently combined with various types of treatments to obtain a more durable antitumor clinical response in patients who have developed resistance to monotherapy. Chemotherapeutic drugs that induce DNA damage and trigger DNA damage response (DDR) frequently induce an increase in the expression of the programmed death ligand-1 (PD-L1) that can be employed by cancer cells to avoid immune surveillance. PD-L1 exposed on cancer cells can in turn be targeted to re-establish the immune-reactive tumor microenvironment, which ultimately increases the tumor's susceptibility to combined therapies. Here we review the recent advances in how the DDR regulates PD-L1 expression and point out the effect of etoposide, irinotecan, and platinum compounds on the anti-tumor immune response.

Efficacy and Safety of PD-L1 Inhibitors plus Chemotherapy versus Chemotherapy Alone in First-Line Treatment of Extensive-Stage Small-Cell Lung Cancer: A Retrospective Real-World Study

Background

Most patients with small-cell lung cancer (SCLC) have extensive-stage (ES) disease with a poor prognosis. Immunotherapy has shown good therapeutic effects in the treatment of ES-SCLC. We performed a real-world retrospective study to evaluate the safety and efficacy of PD-L1 inhibitors plus chemotherapy in patients with ES-SCLC.

Method

A total of 224 patients diagnosed with ES-SCLC between March 2017 and April 2021 were included, of which 115 received only etoposide-platinum (EP) chemotherapy,and 109 received programmed cell-death ligand 1 (PD-L1) inhibitors and EP.

Results

Immune checkpoint inhibitors (ICIs) plus platinum were associated with a significant improvement in overall survival (OS), with a hazard ratio (HR) of 0.60 (95% CI, 0.42–0.85; P=0.0054); median OS was 19 months in the ICIs plus EP group vs. 12 months in the EP group. The median progression-free survival (PFS) was 8.5 and 5.0 months, respectively (HR for disease progression or death, 0.42; 95% CI, 0.31–0.57; P < 0.0001). Male patients <65 years old, Stage IV, PS 0-1, without liver and brain metastasis had a better OS in the ICIs plus EP group than the EP group. The PFS and OS in the durvalumab plus chemotherapy group were insignificantly longer than that of the atezolizumab plus chemotherapy group. Any adverse effects (AEs) of grade 3 or 4 occurred in 50 patients (45.9%) in the ICIs plus EP group and 48 patients (41.7%) in the EP alone group. The most common immune-related AEs (irAEs) were immune hypothyroidism events (17.1%, 7/41), immune dermatitis (9.8%, 4/41), and immune pneumonia (9.8%, 4/41) in the durvalumab plus platinum-etoposide group. Immune liver insufficiency (10.3%, 7/68) and immune hypothyroidism (8.8%, 6/68) were the most common irAEs in the atezolizumab plus platinum-etoposide group.

Conclusion

This study shows that adding PD-L1 inhibitors to chemotherapy can significantly improve PFS and OS in patients with ES-SCLC and demonstrates its safety without additional AEs.