Background: There are scarce data on venous thromboembolism (VTE) rates among non-small cell lung cancer (NSCLC) patients treated with immune-checkpoint inhibitors (ICI). The Khorana Score (KS), used to guide thromboprophylaxis in cancer patients, was validated in patients receiving chemotherapy.Objective: To assess VTE rates and KS performance among NSCLC patients treated with ICI or chemotherapy. Methods:We performed a retrospective cohort study of NSCLC patients starting either ICI or platinum-based chemotherapy. The 6-month cumulative incidence of VTE in the ICI and chemotherapy cohorts and hazard ratios (HR) with 95% confidence intervals (CI) were calculated, using death as a competing risk. Subgroup analysis of low (0-1) and high (≥2) KS risk groups was performed. Results:The study included 345 NSCLC patients receiving single agent ICI (n = 176) or chemotherapy (n = 169). The 6-month cumulative incidence of VTE was 7.1% in the chemotherapy cohort and 4.5% in the ICI cohort (HR for chemotherapy = 1.6, 95% CI 0.66-3.9). Among chemotherapy treated patients, the high-risk KS group had a trend toward a higher VTE incidence, compared with patients with a low-risk KS (HR 3.04, 95% CI 0.82-11.22). Among ICI-treated patients, the high-risk KS group had a trend toward a lower VTE incidence compared with the low-risk group (HR 0.17, 95% CI 0.02-1.36). Conclusions: VTE rates were higher among NSCLC patients treated with platinumbased chemotherapy than those treated with ICI alone, though the precision of the relative estimate is low. The KS did not identify high-risk ICI-treated patients, suggesting that an ICI-specific risk model is warranted.

<b><i>Introduction:</i></b> Immune checkpoint inhibitors (ICI) are the new standard therapy in patients with metastatic NSCLC (mNSCLC). Metformin, previously associated with improved chemotherapy efficacy in diabetic and nondiabetic cancer patients, was recently associated with increased ICI efficacy. In this study, we aimed to explore the correlations between diabetes mellitus (DM), metformin use, and benefit from ICI in mNSCLC patients. <b><i>Methods:</i></b> All mNSCLC patients treated with ICI in our center between February 2015 and April 2018 were identified. Demographic and clinical data were extracted retrospectively. Cox proportional hazards regression, <i>t</i> tests, and χ² tests were employed to evaluate associations of progression-free survival (PFS), overall survival (OS), overall response rate (ORR), and disease control rate (DCR), with DM status, metformin use, and HbA1c levels, as appropriate. <b><i>Results:</i></b> Of 249 mNSCLC patients treated with ICI, 57 (22.8%) had DM. Thirty-seven (64.9% of all diabetic patients) patients were treated with metformin. A significant negative correlation of DM with PFS and OS was demonstrated (HR 1.5 [1.01–2.06], <i>p</i> = 0.011, and HR 1.5 [1.08–2.08], <i>p</i> = 0.017, respectively). Metformin exposure had no significant correlation with PFS or OS in diabetic mNSCLC patients (HR 1.08 [0.61–1.93], <i>p</i> = 0.79, and HR 1.29 [0.69–2.39], <i>p</i> = 0.42, respectively). There were no differences between groups with respect to ORR and DCR. <b><i>Conclusion:</i></b> Our data show a potential negative relationship between DM and ICI efficacy in mNSCLC patients. In contrast to reports with chemotherapy, we found no positive relationship between metformin use and ICI therapy in diabetic patients with mNSCLC. Further studies are needed to evaluate the effect of metformin in nondiabetic mNSCLC patients.

Aim: The treatment paradigm of advanced non-small-cell lung cancer has recently changed with the introduction of immune checkpoint inhibitors (ICIs). It is common practice to continue treatment beyond progression (TBP) in selected cases. The aim of this study was to evaluate real life practice and outcomes related to TBP. Materials & methods: We retrospectively evaluated advanced non-small-cell lung cancer patients treated with ICI therapy and identified patients who were treated beyond progression. Results: Of 207 patients included in this analysis, 22% patients received TBP. A total of 36% achieved a clinical benefit. A total of 27% patients had a progression-free interval over 6 months after receiving TBP. Conclusion: A subset of patients who were treated beyond progression with ICI achieved a clinically meaningful response with durable disease control.

Direct oral anticoagulants (DOACs) are increasingly prescribed in treatment of cancer-associated thrombosis, but limited data exist regarding safety of DOACs in patients with brain metastases. We aimed to determine the incidence of intracranial hemorrhage (ICH) in patients with brain metastases receiving DOACs or low-molecular-weight heparin (LMWH) for venous thromboembolism or atrial fibrillation. An international 2-center retrospective cohort study was designed. Follow-up started on the first day of concomitant anticoagulation and brain tumor diagnosis. At least 2 brain imaging studies were mandated. The primary outcome was the cumulative incidence of any spontaneous ICH at 12-month follow-up with death as a competing risk. Major ICH was defined as spontaneous, ≥10 mL in volume, symptomatic, or requiring surgical intervention. Imaging studies were centrally reviewed by a neuroradiologist blinded for anticoagulant type. PANWARDS (platelets, albumin, no congestive heart failure, warfarin, age, race, diastolic blood pressure, stroke) score for prediction of ICH was calculated. We included 96 patients with brain metastases (41 DOAC, 55 LMWH). The 12-month cumulative incidence of major ICH was 5.1% in DOAC-treated patients and 11.1% in those treated with LMWH (hazard ratio [HR], 0.45; 95% confidence interval [CI], 0.09-2.21). When anticoagulation was analyzed as a time-varying covariate, the risk of any ICH did not differ between DOAC- and LMWH-treated patients (HR, 0.98; 95% CI, 0.28-3.40). PANWARDS score was not associated with ICH risk. This international 2-center study suggests comparable safety of LMWH and DOACs in patients with brain metastases.

11064 Background: CKS is an angioproliferative mesenchymal neoplasm causatively associated with human herpes virus 8 infection. Though recombinant IFNa is approved for treatment of AIDS-related KS, data is limited regarding the role of immune modulation in CKS therapy. Based on favorable responses in viral-induced cancers, we hypothesized that CTLA-4 and PD-1 blockade can induce tumor regression in CKS. We present pre-planned interim analysis of a phase II study of Nivo/Ipi in previously treated progressive CKS (NCT03219671). Methods: CKS pts with progressive disease after ≥ 1 line of systemic therapy and measurable disease by PET/CT and/or physical exam received nivolumab 240mg d1,15,28 and ipilimumab 1mg/kg d1 q42 days until progression or toxicity. The primary endpoint was overall response rate (ORR), secondary endpoints include 6-months progression free survival rate (PFS) and safety. Correlative studies in tumor and serum samples are ongoing using an NGS panel for DNA and RNA and proteomic staining (Tempus Labs Inc). A pre-planned interim analysis was conducted after the first ten enrolled patients for efficacy and toxicity evaluation. Results: Ten patients were enrolled and evaluable between April2018 and February2019. Median age 72 (61-79), all male. At a median FU of 3.1 months (1.5-8.1) ORR was 50% (4 patients PR, 1 patient CR, 5 patients SD). Median PFS was not reached however no progression of disease was documented so far. The safety profile was as expected with all patients experiencing G1 toxicity and four patients with G2 toxicity (1 ALT/AST increase, 2 asymptomatic lipase increase). One SAE was reported (TIA considered not related to therapy) and treatment was discontinued in one patient (G2 LFT increase. maintaining CR 4 months after treatment discontinuation). Correlative results are pending. Conclusions: The interim analysis in this prospectively designed phase II study of nivolumab and low-dose ipilimumab demonstrate promising activity in progressive CKS, with 50% ORR and no events of progression thus far. We expect to report the updated efficacy and correlative data. Clinical trial information: NCT03219671.