EGFR-targeted therapy alters the tumor microenvironment in EGFR-driven lung tumors: Implications for combination therapies.

Immune checkpoint inhibitors targeting the programmed cell death receptor/ligand 1 (PD-1/PD-L1) pathway have profoundly improved the clinical management of non-small-cell lung cancer (NSCLC). Nevertheless, the superiority of single-agent PD-1/PD-L1 inhibitors in pretreated EGFR mutant patients has turned out to be moderate. One proposed mechanism for poor response to immune checkpoint inhibitors is an immunosuppressive tumor microenvironment. Therefore, we utilized two autochthonous EGFR-driven lung tumor models to investigate dynamic microenvironmental responses to EGFR-TKI treatment. We observed that at an early stage, sensitive EGFR-TKIs caused obvious tumor shrinkage accompanied by increased cytotoxic CD8+ T cells and dendritic cells, eradication of Foxp3+ Tregs, and inhibition of M2-like polarization of macrophages. However, the tumor microenvironmental changes that may be most beneficial for combination treatment with immune-mediated anticancer approaches were only temporary and disappeared as treatment continued. Meanwhile, the level of myeloid-derived suppressor cells (MDSCs), particularly mononuclear MDSCs, was consistently elevated throughout the treatment. Analysis of inflammatory factors in serum showed that EGFR-TKIs increased the levels of IL-10 and CCL-2. Our study systematically analyzed dynamic changes in tumor microenvironments responding to EGFR-TKIs in vivo. The results have implications for combination therapy using EGFR-TKIs. The optimal sequence of the treatment and strategies that modulate the tumor microenvironment to a state that may favor antitumor immune responses need to be considered when designing clinical trials.

Patients With Short PFS to EGFR-TKIs Predicted Better Response to Subsequent Anti-PD-1/PD-L1 Based Immunotherapy in EGFR Common Mutation NSCLC.

BACKGROUND: Despite disappointing outcomes from immuno-monotherapy, studies reported that NSCLC patients with EGFR mutation may possibly benefit from combined immunotherapy. Whether the response to prior EGFR-TKI has association with the outcomes of subsequent immunotherapy remains unclear. PATIENTS AND METHODS: Advanced NSCLC patients with resistance to EGFR-TKIs and received ICI treatment from January 2016 to June 2019 were retrospectively analyzed. Single cell sequencing and flow cytometry were conducted to explore the difference of cell components in tumor microenvironments (TME). A 1:3 matched case-control study was conducted to compare the clinical effects of combined immunotherapy with standard chemotherapy as second-line treatment. RESULTS: Fifty-eight patients treated with anti-PD-1/PD-L1 based immunotherapy behind EGFR-TKI treatment were enrolled. Correlation analysis showed TKI-PFS had a significantly negative association with corresponding IO-PFS (r = -0.35, p = 0.006). TKI-PFS cutoff 10 months had the most significant predictive function for posterior immunotherapy and was validated to be an independent predictor by uni- and multivariate analyses. Kaplan-Meier analysis showed that patients with TKI-PFS less than 10 months had significantly prolonged IO-PFS and higher ORR than those with long (median PFS, 15.1 vs 3.8 months; HR, 0.26, p = 0.0002; ORR, 31.8 versus 10%, p = 0.04). Single cell RNA-seq revealed that the cell components were varied among patients after treatment with EGFR-TKI. Patients with short TKI-PFS demonstrated a relatively higher proportion of CD8 effector cells and lower ratio of M2 like macrophage to M1 like macrophages, which was validated by flow cytometry. Case-control study demonstrated that combined immunotherapy achieved significantly longer PFS (HR, 0.51, 95% CI: 0.31-0.85, p = 0.02), longer OS (HR, 0.48, 95% CI: 0.26-0.89, p = 0.05) and higher ORR (33.3 vs 10.0%, p = 0.02) than traditional chemotherapy for patients with short TKI-PFS. CONCLUSION: Patients with short TKI-PFS conferred better response to immunotherapy than those with long. The status of TME were different among those two populations. Combined ICI treatment could promisingly be a better choice than classical chemotherapy in second-line setting for patients with short TKI-PFS and no T790M mutation. Underlying mechanisms need to be further explored.

Concurrent use of metformin enhances the efficacy of EGFR-TKIs in patients with advanced EGFR-mutant non-small cell lung cancer-an option for overcoming EGFR-TKI resistance.

BACKGROUND: Resistance is almost inevitable and is still a major obstacle in epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI) therapy. Only limited relevant clinical studies evaluated the therapeutic effects by combing metformin and EGFR-TKIs in non-small cell lung cancer (NSCLC) patients. Therefore, we evaluated the efficacy of concurrent use of metformin with EGFR-TKIs, and assessed whether the addition of metformin may improve clinical outcomes and delay the occurrence of EGFR-TKI resistance. METHODS: We conducted cell proliferation and apoptosis assay for investigation of metformin in combination with EGFR-TKIs to overcome EGFR-TKI resistance in vitro. Furthermore, we retrospectively reviewed clinicopathological characteristics and therapeutic outcomes of EGFR-mutant advanced NSCLC diabetic patients who received EGFR-TKIs with or without concurrent use of metformin. RESULTS: In vitro experiment, metformin showed synergistic interaction both with gefitinib in PC9R (CI =0.77) and with osimertinib in PC9R/OR (CI =0.77) in proliferation inhibition assay. Metformin can also augment apoptosis effect of these TKI-resistant cells to EGFR-TKIs. In retrospective cohort, a total of 85 patients were identified (cohort A), in which 28 patients had concurrent use of metformin. The objective response rate in metformin use group was significantly higher (85.7% vs. 47.4%, P=0.001). The median progression-free survival (PFS) and overall survival (OS) in metformin use group were significantly longer (21.6 vs. 9.2 months, P=0.000; 48.4 vs. 36.6 months, P=0.049). Further analysis revealed that metformin obviously prolonged the median PFS2 of osimertinib treatment among patients who progressed to prior line EGFR-TKIs due to secondary EGFR T790M mutation (cohort B). CONCLUSIONS: Our study suggest that concurrent use of metformin could be beneficial to EGFR-mutant NSCLC patients treated with either first-line EGFR-TKIs or second-line osimertinib.

Predictive and prognostic significance of M descriptors of the 8th TNM classification for advanced NSCLC patients treated with immune checkpoint inhibitors.

BACKGROUND: A strong association between M descriptors and prognosis of non-small cell lung cancer (NSCLC) has been demonstrated recently. However, its predictive and prognostic significance for advanced NSCLC patients treated with immune checkpoint inhibitors (ICIs) remain unclear. In this study, we aimed at investigating the impact of M descriptors on clinical outcomes in those patients. METHODS: A retrospective analysis was conducted. Patients treated with more than two cycles of ICIs were included. Detailed characteristics and clinical response after immunotherapy were recorded. M descriptors were classified into M1a, M1b, and M1c according to the 8th TNM classification. RESULTS: A total of 103 patients were enrolled, including 42 with M1a disease, 16 with M1b disease and 45 with M1c disease. Patients with M1a disease demonstrated significant longer median progress-free survival (PFS) (11.9 vs. 4.1 and 3.2 months, respectively, P=0.0002) and overall survival (OS) (35 vs. 22.1 and 12 months, P=0.02) than those with M1b and M1c disease. Patients with M1a disease showed higher objective response rate (ORR) (28.6% vs. 14.8%, P=0.08) and disease control rate (DCR) (81% vs. 59%, P=0.02) compared with those with M1b and M1c disease. Multivariate analysis identified M1a stage as being independently associated with prolonged PFS and had better OS than those with M1c disease (P=0.05) but not M1b disease (P=0.06). CONCLUSIONS: The current study demonstrated a clear association between M descriptors and the therapeutic response to ICIs and confirmed its prognostic role in advanced patients treated with ICIs monotherapy. M descriptors may need to be stratified in future study design.

Impact of EGFR-TKIs combined with PD-L1 antibody on the lung tissue of EGFR-driven tumor-bearing mice.

OBJECTIVES: EGFR-targeted tyrosine kinase inhibitors (TKIs) have been the standard treatment for non-small cell lung cancer patients with EGFR mutations. However, most patients eventually develop resistance. With the development of immune checkpoint inhibitors targeting the programmed cell death receptor/ligand 1 (PD-1/PD-L1), there is a growing interest in developing combination strategies. However, there are concerns that the combination of a PD-(L)1 inhibitor and EGFR-TKI may be associated with an increased risk of pneumonitis. Therefore, we utilized an established EGFR-driven tumor-bearing mouse model to investigate whether the combination would induce pneumonitis in mouse lung tissue. MATERIALS AND METHODS: Mice were treated with monotherapy or combined therapy of PD-L1 antibody and EGFR-TKIs including first-generation gefitinib and third-generation osimertinib. Bronchoalveolar lavage fluids (BALFs) and lung tissues were collected for analysis at the end of treatment. RESULTS AND CONCLUSION: The osimertinib and anti-PD-L1 combined treatment group had the highest inflammation scores in pathologic grades of H&E staining of lung tissue and had the highest percentages of myeloperoxidase positive cells. However, combining gefitinib and anti-PD-L1 treatment appeared to not increase the level of pneumonitis in mice. Total cell counts, neutrophil counts and total protein concentration in BALFs were also significantly increased in the osimertinib and anti-PD-L1 combined treatment group. We next evaluated proinflammatory factors in BALFs. The levels of IFN-γ, IL-2, IL-5, TNF-α and IL-12p70 were increased in osimertinib and anti-PD-L1 combined treatment group. Comparison of different sequences of drug administration demonstrated that mice treated with osimertinib followed by PD-L1 antibody did not show evident lung inflammation. Our findings indicate that osimertinib, rather than gefitinib combined with anti-PD-L1 treatment could lead to lung injury in an EGFR mutated tumor-bearing mouse model. The sequence and timing of combining EGFR-TKI and PD-L1 antibody may influence the severity of pneumonitis.

The combination of anti-KIR monoclonal antibodies with anti-PD-1/PD-L1 monoclonal antibodies could be a critical breakthrough in overcoming tumor immune escape in NSCLC.

BACKGROUND: The anti-programmed death-1 (PD-1)/programmed death ligand-1 (PD-L1) monoclonal antibody has a good effect in the treatment of non-small cell lung cancer (NSCLC), but not all PD-1/PD-L1 positive patients can get benefit from it. Compensatory expression of other immune checkpoints may be correlated with the poor efficacy of anti-PD-1/PD-L1 monoclonal antibodies. The inhibitory human leukocyte antigen (HLA)/killer cell Ig-like receptor (KIR) can effectively block the killing effect of natural killer (NK) cells on tumors. Our previous studies have confirmed that high expression of KIR was correlated with poor prognosis of NSCLC. Inhibitory KIR expression was positively correlated with the expression of PD-1. METHODS: The expressions of KIR 2D (L1, L3, L4, S4) (BC032422/ADQ31987/NP_002246/NP_036446, Abcam) and PD-1 (NAT 105, Cell marque) proteins was assessed by immunohistochemistry. RESULTS: The expression of inhibitory KIR in tumor cells or tumor infiltrating lymphocytes (TILs) is associated with PD-1 expression. Among PD-1 positive patients, 76.3% were KIR 2D (L1, L3, L4, S4) positive on tumor cells, and 74.6% were KIR 2D (L1, L3, L4, S4) positive on TILs. We compared the expression of inhibitory KIR before and after treatment with nivolumab in 11 patients with NSCLC. We found that five (45.5%) patients had positive expression of inhibitory KIR in tumor tissue after being treated with anti-PD-1 monoclonal antibodies, two of whom exhibited a significant increase in expression of inhibitory KIR, and three showed no change. CONCLUSIONS: PD-1 expression was correlated with KIR 2D (L1, L3, L4, S4) on tumor cells or TILs. The resistance to anti-PD-1 monoclonal antibody treatment might be related to KIR. The inhibitory HLA/KIR could combine with the PD-1/PD-L1 signaling pathway negatively regulating NSCLC tumor immunity.

Impact of serum vascular endothelial growth factor and interleukin-6 on treatment response to epidermal growth factor receptor tyrosine kinase inhibitors in patients with non-small-cell lung cancer.

BACKGROUND: Although EGFR-tyrosine kinase inhibitors (EGFR-TKIs) are the standard treatment for patients with EGFR-mutant non-small-cell lung cancer (NSCLC), responses vary within individuals. The current study aimed to investigate whether serum levels of several cytokines and their dynamic changes during TKI treatment could be used to predict the efficacy of EGFR-TKIs. MATERIALS AND METHODS: Pre-treatment and one-month post-treatment serum levels of hepatocyte growth factor (HGF), interleukin-10 (IL-10), interleukin-6 (IL-6), vascular endothelial growth factor (VEGF), interferon gamma (IFN-γ) and monocyte chemotactic protein-1 (MCP-1) were measured using enzyme-linked immunosorbent assay and U-plex biomarker group assays in patients with EGFR-mutant NSCLC received first-line EGFR-TKIs. RESULTS: Patients who had lower baseline serum levels of IL-6 had better object response rate (ORR) than those with high levels (74.2% vs 42.9%, p = 0.014). PFS was significantly longer in patients with low baseline level of IL-6 (19.57 vs. 13.73 months, p = 0.003) and in those with reduced serum VEGF and HGF levels after treatment (20.30 vs. 14.33 months, p = 0.009; 22.77 vs. 14.33 months, p = 0.002; respectively). Multivariate analyses showed that lower baseline serum IL-6 level was significantly associated with longer PFS (HR = 0.469, p = 0.022) and OS (HR = 0.181, p = 0.004). Reduction of serum VEGF and HGF levels after treatment was associated with significantly longer PFS (HR = 0.447, p = 0.017; HR = 0.365, p = 0.003; respectively). Lower pre-treatment serum VEGF level was associated with dramatically longer OS (HR = 0.277, p = 0.018). CONCLUSIONS: Our study suggested that serum levels of HGF, IL-6 and VEGF and its dynamic change during TKI treatment could be used to predict the efficacy of EGFR-TKIs treatment in patients with EGFR-mutant NSCLC.

EGFR-TKIs plus chemotherapy demonstrated superior efficacy than EGFR-TKIs alone as first-line setting in advanced NSCLC patients with EGFR mutation and BIM deletion polymorphism.

BACKGROUND: Non-small-cell lung cancer (NSCLC) patients with both epidermal growth factor receptor (EGFR) positive mutation and B-cell chronic lymphocytic leukemia/lymphoma-like 11 (BIM) deletion polymorphism had a poor clinical response to EGFR-tyrosine kinase inhibitors (TKIs). The current study aimed to investigate the clinical efficacy and tolerability of EGFR-TKIs plus chemotherapy versus EGFR-TKIs alone as first-line treatment in advanced NSCLC patients with EGFR mutations and BIM deletion polymorphism. METHODS: A retrospective, non-randomized analysis was conducted. BIM deletion polymorphism was detected using polymerase chain reaction (PCR) analysis and direct sequencing of DNA from peripheral blood cells. Clinical characteristics, overall survival (OS), progress-free-survival (PFS), objective response rate (ORR) and treatment-related adverse events were compared between EGFR-TKIs alone versus EGFR-TKIs plus chemotherapy group. RESULTS: 65 patients were enrolled. 36 of them received EGFR-TKIs and 29 received EGFR-TKIs plus chemotherapy. EGFR-TKIs plus chemotherapy had significantly higher ORR than TKIs alone (65.5% vs. 38.9%, P = 0.046). Median PFS was significantly longer in EGFR-TKIs plus chemotherapy group than in TKIs group (7.2 vs 4.7 m; P = 0.008). Median OS was numerically longer in EGFR-TKIs plus chemotherapy group than in TKIs alone (18.5 vs 14.2 m; P = 0.107). EGFR-TKIs plus chemotherapy was associated with more grade 3 or 4 hematological toxic effects than EGFR-TKIs alone. CONCLUSION: EGFR-TKIs plus chemotherapy conferred a significantly higher ORR, prolonged PFS and numerically longer OS in advanced NSCLC patients with EGFR mutation and BIM deletion polymorphism. Further prospective studies are needed to validate these findings.