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Introduction Upfront criteria to foresee immune checkpoint inhibitors (ICIs) efficacy are far from being identified. Thus, we integrated blood descriptors of pro-inflammatory/immunosuppressive or effective anti-tumor response to non-invasively define predictive immune profiles in ICI-treated advanced non-small cell lung cancer (NSCLC). Methods Peripheral blood (PB) was prospectively collected at baseline from 109 consecutive NSCLC patients undergoing ICIs as first or more line treatment. Soluble PD-L1 (sPD-L1) (immunoassay), CD8+PD-1+ and NK (FACS) cells were assessed and interlaced to generate an Immune effector Score (IeffS). Lung Immune Prognostic Index (LIPI) was computed by LDH levels and derived Neutrophil-to-Lymphocyte Ratio (dNLR). All these parameters were correlated with survival outcome and treatment response. Results High sPD-L1 and low CD8+PD-1+ and NK number had negative impact on PFS (P Conclusion Composite risk models based on blood parameters featuring the tumor-host interaction might provide accurate prognostic scores able to predict ICI benefit in NSCLC patients.

Anaplastic lymphoma kinase tyrosine kinase inhibitors (ALK-TKIs) are the standard treatment for advanced ALK-positive non-small cell lung cancer (NSCLC) allowing survivals up to 5 years. However, duration of responses is limited by the almost certain occurrence of drug resistance. Here, we report a case of a never smoker, 59-year-old female with metastatic ALK-positive adenocarcinoma, solid and signet ring patterns, who developed resistance to alectinib, a second-generation ALK-TKI, mediated by HER2 gene amplification. The patient received 22 months of crizotinib as first-line and subsequently 1-year of alectinib therapy. A study of resistance mechanism was performed with next generation sequencing (NGS) on tissue re-biopsy. A HER2-amplified emerging clone was identified by NGS in a liver metastasis and confirmed by fluorescent in situ hybridization (FISH) analysis. The resistant clone was detectable 2 months before disease progression in plasma cell-free DNA (cfDNA) using digital droplet PCR (ddPCR) copy number variation (CNV) assay and it was retrospectively traced in rare cells of the lung primary by FISH. To our best knowledge, this is first evidence of HER2 gene amplification as a resistance mechanism to ALK-TKI in a NSCLC. Future strategies against oncogene-addicted NSCLC might benefit of combined drug treatments, such as ALK and HER2 inhibition.

Objective: To investigate the role of CTLA-4, PD-1 (programmed death-1), and PD-L1 (programmed death-ligand 1) single nucleotide polymorphisms (SNPs) in predicting clinical outcome of patients with advanced non-small cell lung cancer (NSCLC) treated with immune checkpoint inhibitors (ICIs). Methods: A total of 166 consecutive patients were included. We correlated SNPs with clinical benefit, progression-free survival, time to treatment failure, and overall survival and evaluated the incidence of SNPs in nonresponder and long clinical benefit groups. Results: Considering the entire cohort, no correlation was found between SNPs and clinical outcome; however, PD-L1 rs4143815 SNP and the long clinical benefit group showed a statistically significant association ( p = 0.02). The nonresponder cohort displayed distinctive PD-L1 haplotype ( p = 0.05). Conclusion: PD-L1 SNPs seem to be marginally involved in predicting clinical outcome of NSCLC treated with ICI, but further investigations are required.

Analysis of circulating tumor DNA (ctDNA) for the identification of T790M mutation in advanced EGFR-mutated NSCLC patients can replace tissue re-biopsy for resistance characterization and, being non-invasive, may be applied for disease monitoring. We analysed ctDNA during osimertinib treatment to correlate mutational levels with clinical outcome and to predict pattern of resistance.Forty patients with advanced NSCLC receiving osimertinib for T790M + disease after previous EGFR-TKI were enrolled in a pilot study to collect plasma at baseline and every 12 weeks until progression. Molecular analysis of ctDNA was performed by ddPCR and Therascreen®. When feasible at progression, tissue re-biopsy and NGS analysis were performed.Thirty-eight patients had baseline plasma samples suitable for molecular analysis. Patients with low levels of the EGFR activating mutation in ctDNA [2200 copies/mL or allele frequency (AF)6.1%] showed better progression-free survival (17.8 or 17.8 months vs. 4.3 or 2.7, p = 0.022 or p = 0.018, respectively) and overall survival (23.6 or 23.6 vs. 7.7 or 7.3, p = 0.016 or p = 0.013, respectively) than patients with high levels (≥ 2200 copies/mL or AF ≥ 6.1%). Patients with detectable EGFR mutations in plasma (shedders) presented worse outcome than negative subjects (non-shedders). Low levels of T790M, higher T790M/activating mutation ratio and complete clearance after 2 months were associated with a trend towards better outcome. Tissue re-biopsy at resistance showed 3 patients with EGFR C797S, 1 with MET amplification, 1 with MYC amplification, 1 with PTEN loss, 3 with SCLC transformation.The mutational analysis performed on plasma plays a significant role in prognostic stratification, especially for the EGFR activating mutation, since patients with absence or low levels of mutations presented a better outcome to osimertinib. At progression, tissue re-biopsy remains a crucial issue for the identification of resistance mechanisms.

Aim: This prospective study aimed to envisage the putative prognostic significance of clinical and hematologic parameters in advanced non-small-cell lung cancer patients treated with nivolumab. Materials & methods: Correlations of several parameters with disease control and survival outcomes were provided. Results: A total of 54 patients were included. An ECOG performance status 0–1, the lack of liver and bone metastases and a timeframe from the last systemic treatment ≥4 months correlated with better disease control. The same was observed for baseline low levels of white blood cells and neutrophils, for high levels of NK cells and a neutrophil/lymphocyte ratio

Background Predictive biomarkers of immune checkpoint inhibitors (ICIs) efficacy in NSCLC are still an unmet goal. PD-L1 expression at tissue level (tPD-L1) is not steadily assessable in metastatic setting and, although routinely recommended, its dynamic nature hinders an accurate estimation. Thus, the aim of our study was to determine whether embodying genetic, tissue and circulating PD-L1 status may predict ICI response in NSCLC patients. To encompass PD-L1/PD-1 axis, we investigated the incidence of PD-1 receptor on circulating T-lymphocytes. Methods Peripheral blood (PB) samples from 80 consecutive ICI-treated NSCLC patients were collected at baseline. Soluble PD-L1 (sPD-L1) was measured by Human/Cynomolgus Monkey PD-L1/B7-H1 Immunoassay (R&D Systems). PD-L1 polymorphisms (rs2282055, rs4143815) were determined by RT PCR using TaqMan® method. FACS analysis was performed to detect PD-1 expression on T cells. Available tissue sections were immunohistochemically stained for tPD-L1 scoring. All these parameters were correlated with patient characteristics, survival outcome and response to treatment. Results sPD-L1 values ranged from 14.8 to 189.8 pg/ml (median 62.8 pg/ml). High sPD-L1 and low number of PB CD8+PD-1+ lymphocytes were detected in NSCLC cases displaying ECOG PS = 2, >3 metastatic sites, liver and pleural involvement (p Conclusion Our preliminary results support sPD-L1 as a promising biomarker of ICI benefit. The simultaneous assessment of the pool size of PB PD1+ effector cells might implement the strategy to predict NSCLC survival and response to treatment. Legal entity responsible for the study University Hospital of Parma. Funding Has not received any funding. Disclosure All authors have declared no conflicts of interest.

e14514 Background: Detection of predictive markers of anti-PD-1/PD-L1 antibodies activity is of pivotal interest in non-small cell lung cancer (NSCLC). This study aimed to identify a circulating immuno-profile as predictor of outcome in NSCLC patients treated with nivolumab Methods: A peripheral blood immuno-profile evaluation was performed at baseline (T0), after 2 (T1) and 4 cycles (T2) of bi-weekly nivolumab in advanced pre-treated NSCLC patients from two Italian Institutions. First tumor assessment was performed after 4 cycles and then every 2 months. FACS analysis of lymphocyte subpopulations [CD3, CD4, CD8, NK (CD56), Treg (FOXP3) and MDSC] was performed. Absolute and % changes of lymphocyte subsets together with their functional and proliferative activity were assessed. Quali-quantitative leucocyte composition at baseline and its variation during therapy were correlated with tumor response and survival. Results: In the overall population of 54 treated patients, baseline Neutrophil-to-Lymphocyte ratio and NK count, lymphocyte count and CD4 variations during therapy showed a statistically significant prognostic role (p < 0.001; p = 0.012; p < 0.001; p = 0.010, respectively). Among 31 patients (squamous carcinoma, n = 17; adenocarcinoma, n = 14) in which all 3 time-points samples were available, 19 were responders (response and stable disease) and 12 non-responders. In responders, absolute numbers of total NK and NKCD56dim subset were higher at baseline and their increase between T0 and T1 was statistically significant (p < 0.05). Responders also displayed increased cytotoxic capability as shown by a higher baseline expression of CD3ζ, perforin and granzyme in NKCD56dim subset. No significant variation was documented in absolute number and functional activity of CD4+ and CD8+ lymphocytes. A higher percentage of CD8+PD-1+ cells at baseline was observed in responders, while non-responders showed a statistically significant increase in the absolute number of MDSC during therapy (p < 0.05). Conclusions: The number and function of NKs and the frequency of PD-1 expression in CD8+ cells could represent predictive peripheral immuno-biomarkers for nivolumab treatment in advanced NSCLC.

50 Background: hypovitaminosis D is frequent in renal diseases but it was never reported in metastatic renal cell carcinoma (mRCC). The interaction between vitamin D and its receptor (VDR) has a key role for T-cell activation. Naïve T-cells do not express VDR and had very low expression of phospholipase C-γ1 (PLC-γ1), with low responsiveness to T-cell receptor (TCR). Initial TCR signaling induces VDR expression and upregulates PLC-γ1 via the kinase p38 pathway. VDR interaction with high concentrations of vitamin D and PLC-γ1 increase are required to trigger classical TCR signaling, increasing T-cell responsiveness. On these basis, we hypothesized that hypovitaminosis D could contribute to lower responsiveness to immune-checkpoint inhibitors (CKI). Methods: we assessed vitamin D levels of mRCC patients undergoing therapy with CKI, with the aim to reveal hypovitaminosis D, evaluate its prevalence and hypothesize its potential role in the outcome of treatment with CKI. Results: of 10 mRCC patients pretreated with tyrosine-kinase inhibitors, vitamin D levels assessed before the first treatment with nivolumab (anti-PD1 CKI) revealed deficiency in 80% of cases (8 patients). Hypovitaminosis D was severe ( < 20 ng/ml) in 7 cases and moderate ( < 30 ng/ml) in one. The 2 patients without deficiency (20%), had vitamin D values near to the lower limit of normality. Oral supplementation with cholecalciferol was given when necessary, likely confounding the possible influence of vitamin D deficiency on the outcome of CKI treatment. Vitamin D normal values after two months of therapy were recovered in the great majority of cases. Interestingly, the only patient who achieved a good objective response to treatment had normal values of vitamin D before therapy. Conclusions: hypovitaminosis D could have a relevant prevalence in mRCC patients. Considering the role of vitamin D in T-cell activation, assessment of its levels and initiation of a supplementation before immunotherapy should be considered to enhance responsiveness. On the basis of these observations, we are planning a perspective multicenter study to investigate the role of hypovitaminosis D in mRCC patients treated with CKI (PRoviDenCe study).

494 Background: In clinical trials with immune-checkpoint inhibitors (CKI), histological features such as tumor-infiltrating lymphocites (TILs) are investigated as potential predictive biomarkers, with the possible limit of an outdated parameter for a typically dynamic element. Methods: This explorative study compared, in metastatic renal cell carcinoma (mRCC) patients, basal pathological data about TILs on diagnostic histological specimens with circulating lymphocyte subpopulations measured before and during therapy with nivolumab, with the primary aim to assess their concordance. Secondarily, with the limit of a small sample size, a possible relation with treatment outcome was explored. Results: Of 11 mRCC patients, 5 had low presence of TILs (L-TILs), 3 moderate amount (M-TILs), and 3 high number (H-TILs). Overall, 8 patients had low intratumoral pathological CD4+/CD8+ ratio (LIPR) ≤ 1 and 3 cases high intratumoral pathological ratio (HIPR) ≥ 2. Of 8 patients with LIPR, only 2 cases matched with low circulating CD4+/CD8+ ratio (LCR) ≤1, whilst 5 cases had high circulating ratio (HCR) ≥ 2 (1 undetermined). All 3 cases with HIPR (≥ 2) conversely had LCR (≤ 1). Unexpectedly, independently from the clinical outcome, circulating CD4+/CD8+ ratio remained unchanged during therapy with CKI in each patient, maintaining the same value after 8 weeks (mean -0.12). The respective percentage values of CD4+ and CD8+ circulating T cells also remained stable during treatment (mean variation 0%); the absolute value of CD4+ was more likely to increase (mean +46.3/mm3); the level of CD8+ tended to slightly decrease (mean -6.5/mm3). No correlation of lymphocyte subpopulations with treatment outcome was found. Conclusions: Of note, this study did not evidence any correspondence between histopathological and circulating findings in terms of T-lymphocyte subpopulations in mRCC patients undergoing treatment with CKI, also suggesting the inconsistency of circulating data in terms of relative variations. Considering the likely high dynamism of TILs, rebiopsy before CKI therapy might be the most reliable way to assess the utility of TILs characterization for predictive purpose.