Long-term survival in patients with advanced non-small-cell lung cancer treated with atezolizumab versus docetaxel: Results from the randomised phase III OAK study.

BACKGROUND: Atezolizumab (anti-programmed death-ligand 1 [PD-L1]) received approval from the US Food and Drug Administration and European Medicines Agency for previously treated advanced non-small-cell lung cancer based on OAK-a randomised, phase III trial that showed significantly improved survival with atezolizumab versus docetaxel regardless of PD-L1 expression. With longer follow-up, we summarised the characteristics of long-term survivors (LTSs). METHODS: In OAK (NCT02008227), patients were randomised 1:1 to receive atezolizumab or docetaxel until loss of clinical benefit or disease progression, respectively. Overall survival was evaluated after a 26-month minimum follow-up, including in patient subgroups defined by best overall response (BOR). LTSs were defined as patients who lived ≥24 months since randomisation. Non-LTSs died within 24 months, and patients censored before 24 months were excluded from the analysis. The baseline characteristics, including biomarkers, BOR, subsequent non-protocol therapy (NPT) and safety, are reported. RESULTS: Survival benefit with atezolizumab was observed across all patient subgroups defined by BOR. More atezolizumab-treated patients were LTSs versus those treated with docetaxel (28% versus 18%). Most atezolizumab responders were LTSs (77%) versus only 48% of docetaxel responders. However, 21% of atezolizumab-arm LTSs had progressive disease (PD) as BOR, and more atezolizumab-arm LTSs than non-LTSs continued treatment post-PD. Fifty-two percent of docetaxel-arm LTSs received immunotherapy as subsequent NPT. Despite extended treatment duration in atezolizumab-arm LTSs (median, 18 months), atezolizumab was well tolerated. CONCLUSIONS: After >2 years of follow-up, atezolizumab continued to provide durable survival benefit versus docetaxel, with tolerable safety. Atezolizumab-arm LTSs were enriched for patients with high PD-L1 expression and included PD-L1-negative patients. Long-term survival was not limited to responders.

Detection of PD-L1 in circulating tumor cells and white blood cells from patients with advanced non-small-cell lung cancer.

Background: Expression of PD-L1 in tumor cells and tumor-infiltrating immune cells has been associated with improved efficacy to anti-PD-1/PD-L1 inhibitors in patients with advanced-stage non-small-cell lung cancer (NSCLC) and emerged as a potential biomarker for the selection of patients to cancer immunotherapies. We investigated the utility of circulating tumor cells (CTCs) and circulating white blood cells (WBCs) as a noninvasive method to evaluate PD-L1 status in advanced NSCLC patients. Patients and methods: CTCs and circulating WBCs were enriched from peripheral blood samples (ISET® platform; Rarecells) from 106 NSCLC patients. PD-L1 expression on ISET filters and matched-tumor tissue was evaluated by automated immunostaining (SP142 antibody; Ventana), and quantified in tumor cells and WBCs. Results: CTCs were detected in 80 (75%) patients, with levels ranging from 2 to 256 CTCs/4 ml, and median of 60 CTCs/4 ml. Among 71 evaluable samples with matched-tissue and CTCs, 6 patients (8%) showed ≥1 PD-L1-positive CTCs and 11 patients (15%) showed ≥1% PD-L1-positive tumor cells in tumor tissue with 93% concordance between tissue and CTCs (sensitivity = 55%; specificity = 100%). From 74 samples with matched-tissue and circulating WBCs, 40 patients (54%) showed ≥1% PD-L1-positive immune infiltrates in tumor tissue and 39 patients (53%) showed ≥1% PD-L1 positive in circulating WBCs, with 80% concordance between blood and tissue (sensitivity = 82%; specificity = 79%). We found a trend for worse survival in patients receiving first-line cisplatin-based chemotherapy treatments, whose tumors express PD-L1 in CTCs or immune cells (progression-free and overall survival), similar to the effects of PD-L1 expression in matched-patient tumors. Conclusions: These results demonstrated that PD-L1 status in CTCs and circulating WBCs correlate with PD-L1 status in tumor tissue, revealing the potential of CTCs assessment as a noninvasive real-time biopsy to evaluate PD-L1 expression in patients with advanced-stage NSCLC.

Characterization of an imatinib-sensitive subset of high-grade human glioma cultures.

High-grade gliomas, including glioblastomas, are malignant brain tumors for which improved treatment is urgently needed. Genetic studies have demonstrated the existence of biologically distinct subsets. Preliminary studies have indicated that platelet-derived growth factor (PDGF) receptor signaling contributes to the growth of some of these tumors. In this study, human high-grade glioma primary cultures were analysed for sensitivity to treatment with the PDGF receptor inhibitor imatinib/Glivec/Gleevec/STI571. Six out of 15 cultures displayed more than 40% growth inhibition after imatinib treatment, whereas seven cultures showed less than 20% growth inhibition. In the sensitive cultures, apoptosis contributed to growth inhibition. Platelet-derived growth factor receptor status correlated with imatinib sensitivity. Supervised analyses of gene expression profiles and real-time PCR analyses identified expression of the chemokine CXCL12/SDF-1 (stromal cell-derived factor 1) as a predictor of imatinib sensitivity. Exogenous addition of CXCL12 to imatinib-insensitive cultures conferred some imatinib sensitivity. Finally, coregulation of CXCL12 and PDGF alpha-receptor was observed in glioblastoma biopsies. We have thus defined the characteristics of a novel imatinib-sensitive subset of glioma cultures, and provided evidence for a functional relationship between imatinib sensitivity and chemokine signaling. These findings will assist in the design and evaluation of clinical trials exploring therapeutic effects of imatinib on malignant brain tumors.

Epidermal growth factor and pro-inflammatory cytokines regulate the expression of components of plasminogen activation system in U373-MG astrocytoma cells.

Cytokines and growth factors that influence both secretion of the extracellular matrix (ECM) proteins and migration of the cells decide about the final outcome of tissue remodelling. We have examined expression of the components of the plasminogen activation system in human astrocytoma U373-MG cells and found that interleukin 1beta (IL-1beta), tumour necrosis factor alpha TNF-alpha), interferon gamma (INF-gamma) and epidermal growth factor (EGF) specifically regulate the expression of tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA), plasminogen activator inhibitor type 1 (PAI-1) and protease nexin-1 (PN-1). We conclude that EGF and IFN-gamma are new important regulators of the plasminogen activation system in astrocytoma cells and, therefore, may influence turnover of extracellular matrix and migration of cells within the brain.