PD-1/L1 axis-directed therapies produce clinical responses in a subset of patients; therefore, biomarkers of response are needed. We hypothesized that quantifying key immunosuppression mechanisms within the tumor microenvironment by multiparameter algorithms would identify strong predictors of anti-PD-1 response. Pretreatment tumor biopsies from 166 patients treated with anti-PD-1 across 10 academic cancer centers were fluorescently stained with multiple markers in discovery ( = 24) and validation ( = 142) cohorts. Biomarker-positive cells and their colocalization were spatially profiled in pathologist-selected tumor regions using novel Automated Quantitative Analysis algorithms. Selected biomarker signatures, PD-1/PD-L1 interaction score, and IDO-1/HLA-DR coexpression were evaluated for anti-PD-1 treatment outcomes. In the discovery cohort, PD-1/PD-L1 interaction score and/or IDO-1/HLA-DR coexpression was strongly associated with anti-PD-1 response ( = 0.0005). In contrast, individual biomarkers (PD-1, PD-L1, IDO-1, HLA-DR) were not associated with response or survival. This finding was replicated in an independent validation cohort: patients with high PD-1/PD-L1 and/or IDO-1/HLA-DR were more likely to respond ( = 0.0096). These patients also experienced significantly improved progression-free survival (HR = 0.36; = 0.0004) and overall survival (HR = 0.39; = 0.0011). In the combined cohort, 80% of patients exhibiting higher levels of PD-1/PD-L1 interaction scores and IDO-1/HLA-DR responded to PD-1 blockers ( = 0.000004). In contrast, PD-L1 expression was not predictive of survival. Quantitative spatial profiling of key tumor-immune suppression pathways by novel digital pathology algorithms could help more reliably select melanoma patients for PD-1 monotherapy. .

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102 Background: Addition of pembrolizumab (P) to platinum-doublet chemotherapy [carboplatin (or cisplatin) and pemetrexed (CP)] prolongs overall survival and is a standard of care (SOC) for the 1st line treatment of metastatic EGFR/ALK wild-type (wt) non-squamous non-small cell lung cancer (mnsNSCLC). Despite widespread adoption of the CPP regimen, molecular determinants of clinical benefit from the addition of P to CP remain poorly defined. We previously identified genomic alterations in STK11/LKB1 as a major driver of primary resistance to PD-1/PD-L1 blockade in mnsNSCLC. Here, we examine the impact of STK11/LKB1 alterations on clinical outcomes with CPP chemo-immunotherapy. Methods: 497 pts with mnsNSCLC and tumor genomic profiling encompassing STK11/LKB1 from 17 academic institutions in the US and Europe were included in this study. Clinical outcomes were collected for two distinct patient cohorts: a) 377 pts treated with first-line CPP (or > 1st line following FDA-approved TKIs) that were alive for 14 days thereafter and b) 120 STK11/LKB1-mt pts that received CP prior to regulatory approval of CPP. Results: Among 377 CPP-treated pts, STK11/LKB1 genomic alterations (N = 102) were associated with significantly shorter PFS (mPFS 4.8m vs 7.2m, HR 1.5, 95% CI 1.1 to 2.0; P = 0.0063) and shorter OS (mOS 10.6m vs 16.7m, HR 1.58, 95% CI 1.09 to 2.27; P = 0.0083) compared with STK11/LKB1-wt tumors (N = 275). ORR also differed significantly between the two groups (32.6% vs 44.7%, P = 0.049). Similar results were obtained when limiting the analysis to EGFR and ALK-wt tumors (N = 333). Importantly, in pts with STK11/LKB1-mt mnsNSCLC, addition of pembrolizumab to CP did not improve PFS (mPFS 4.8m vs 4.3m, HR 1.13, 95% CI 0.83 to 1.54, P = 0.75) or OS (mOS 10.6m vs 10.3m, HR 1.03, 95% CI 0.71 to 1.49, P = 0.79) compared to CP alone. Conclusions: In mnsNSCLC, STK11/LKB1 alterations define a subgroup of pts with inferior clinical outcomes with CPP and lack of benefit from the addition of pembrolizumab to CP chemotherapy. Novel therapeutic strategies are required to establish effective antitumor immunity in STK11/LKB1-mutant NSCLC.

Introduction: This study aims to determine whether advanced ROS1 gene-rearranged NSCLC (ROS1þ NSCLC) has a higher than expected thromboembolic event (TEE) rate.Methods: Venous and arterial TEEs within ±365 days of diagnosis of ROS1þ, ALKþ, EGFRþ, or KRASþ advanced NSCLC at five academic centers in the United States and China were captured (October 2002-April 2018). The primary endpoint was incidence of TEE in ROS1þ compared to anaplastic lymphoma kinase (ALK)þ, EGFRþ, and KRASþ NSCLC within ±90 days of diagnosis. Logistic regression was used to assess if the odds of TEE differed among oncogene drivers.Results: Eligible data from 95 ROS1þ, 193 ALKþ, 300 EGFRþ, and 152 KRASþ NSCLC patients were analyzed. The incidence rate of TEE was 34.7% (n ¼ 33), 22.3% (n ¼ 43), 13.7% (n ¼ 41), and 18.4% (n ¼ 28), respectively. In univariate analysis, the odds of a TEE in ROS1þ NSCLC were higher than ALKþ, EGFRþ, and KRASþ cohorts. In multivariable analysis, the odds of a TEE were significantly higher for ROS1þ compared to EGFRþ and KRASþ cohorts, the odds ratio (OR) was 2.44, with a 95% confidence interval of 1.31-4.57 (p ¼ 0.005), and OR: 2.62, with a 95% confidence interval of 1.26-5.46 (p ¼ 0.01), respectively.Although numerically superior, the odds for a TEE with ROS1þ compared to ALKþ was not statistically significant (OR: 1.45, p ¼ 0.229). Overall survival was not significantly

BACKGROUND: This multicenter, retrospective study explored the value of oncogene driver subtype, programmed death-1 ligand (PD-L1) status, and smoking status for predicting which patients with oncogene-driven non-small cell lung cancer (NSCLC) would benefit from treatment with programmed death-1 (PD-1)/PD-L1 inhibitors. METHODS: The clinical features, PD-L1 tumor proportion scores, and PD-1/PD-L1 inhibitor (PDi) outcomes (objective response rate and progression-free survival) of patients who had advanced NSCLC with Kirsten rat sarcoma 2 viral oncogene homolog (KRAS) mutations or common, actionable oncogenic drivers were captured. RESULTS: In total, 189 oncogene-positive patients were analyzed. Of these, 104 received a PDi, and 108 had undergone prior PD-L1 testing. The frequency of PD-L1 positivity (≥1%) was higher in patients who had KRAS mutations (P = .031), smokers (P = .006), and non-Asian patients (P = .002). Multivariable analysis indicated that smoking status (P < .001) was the only factor associated significantly with KRAS mutation. The objective response rate to PDi treatment was 16.9% (11 of 65 patients) among smokers (17.3% in the KRAS-mutant and 15.4% in the non-KRAS-mutant smoker subgroups), which was significantly higher than the 0% rate (0 of 26 patients; P = .019) among never-smokers. In subgroup analyses, progression-free survival was influenced by KRAS mutation status (median, 4.57 vs 1.63 months; P = .004), smoking status (4.07 vs 1.73 months; P = .004), PD-L1 positivity (3.8 vs 1.2 months; P = .040), and non-Asian race (3.0 vs 1.97 months; P = .046). In multivariable analysis, only smoking status (P = .008) remained a significant predictor when a PD-L1 level ≥1% was used. However, both smoking status (P = .001) and PD-L1 status (P = .028) were independent predictors when a PD-L1 level ≥50% was used. CONCLUSIONS: Among associated clinical features among patients who have NSCLC with oncogenic drivers, smoking status potentially was the most important, easily available predictor of single PDi efficacy.