The risk of venous and arterial thromboembolism (VTE/ATE) associated with immune checkpoint inhibitors is currently unclear, and clinical trials evaluating these agents in patients with cancer did not provide information. Our aim was to quantify risk of VTE/ATE in a cohort of patients treated with immune checkpoint inhibitors, explore clinical impact, and investigate potential clinical risk factors. Patients treated with an immune checkpoint inhibitor at the Medical University of Vienna from 2015-2018 were identified using the in-house pharmacy records (n=672; most frequent entities: 30.4% melanoma, 24.1% non-small-cell lung cancer; 86% stage-IV-disease). A retrospective chart-review was performed to screen for VTE and/or ATE. Cumulative incidences and between-group differences were analysed within a competing-risk framework. Multi-state modelling was applied to study the impact of VTE/ATE on mortality. Over a median follow-up of 8.5 months, 47 VTE and 9 ATE were observed. Cumulative incidences of VTE and ATE were 12.9% [95% confidence interval (CI): 8.2-18.5)] and 1.8% [95%CI: 0.7-3.6]. Occurrence of VTE was associated with increased mortality (transition hazard-ratio (THR): 3.09 [95%CI: 2.07-4.60]. History of VTE predicted VTE occurrence (subdistribution hazard ratio (SHR): 3.69 [2.00-6.81]) and distant metastasis was non-significantly associated with VTE risk (SHR: 1.71 [95%CI: 0.62-4.73]). No association of VTE with ECOG performance-status, Charlson-Comorbidity-Index or the Khorana-score was observed, and rates of VTE were comparable among subgroups of tumour types and checkpoint-inhibitory agents. In conclusion, patients with cancer under immune checkpoint inhibitor therapy are at high risk of thromboembolism, especially VTE. Furthermore, VTE occurrence was associated with increased risk of mortality.

Objective: Pancreatic cancer activates coagulation and increases risk of venous thromboembolism (VTE). We aimed at characterizing the association of hemostatic biomarkers and VTE with mortality and chemotherapy response. Approach and Results: Pancreatic cancer patients (n=145) were included in a prospective, observational cohort study (CATS [Vienna Cancer and Thrombosis Study]). Hemostatic biomarkers (D-dimer, extracellular vesicle–tissue factor activity, prothrombin fragment 1+2, fibrinogen, factor VIII, PAI-1 [plasminogen activator inhibitor 1], sP-selectin [soluble P-selectin], thrombin generation assay) were measured at inclusion. The impact of VTE on overall survival/progression-free survival (OS/PFS) was evaluated by multistate modeling. The association of biomarkers with OS was analyzed by Cox-regression and with PFS and disease control rate in patients initiating palliative chemotherapy (n=95) by Cox-regression and logistic regression. Multivariable analysis included stage, grade, sex, age, performance status, VTE (time-dependent), vascular infiltration/compression, and tumor marker levels (carbohydrate-antigen 19-9, carcinoembryonic antigen). VTE occurrence was associated with shorter OS (transition hazard ratio, 3.40 [95% CI, 2.05–5.64]) and shorter PFS (transition hazard ratio, 2.10 [1.16–3.79]). Median post-VTE OS/PFS in months was 5.5 [2.2–6.5] and 3.0 [1.5–3.9], compared with 13.4 [9.7–16.6] and 7.5 [5.9–9.8] in patients without VTE (both P <0.001). D-dimer, extracellular vesicle–tissue factor activity, PAI-1, and sP-selectin were associated with increased mortality (hazard ratio per doubling, 1.27 [1.00–1.61]; 1.63 [1.14–2.36]; 1.25 [1.06–1.47]; 1.52 [1.05–2.20]). In patients initiating palliative chemotherapy, higher D-dimer predicted shorter PFS (hazard ratio per doubling, 1.27 [1.01–1.60]) and lower disease control rate (odds ratio per doubling, 0.59 [0.36–0.98]). Conclusions: VTE diagnosis is associated with shorter OS and PFS. Higher baseline levels of D-dimer, extracellular vesicle–tissue factor activity, PAI-1, and sP-selectin were independently prognostic for increased mortality, and D-dimer predicted response to palliative chemotherapy.

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q3w with an incidence ratio of 1.13 (0.19 e 4.70). Both groups had a high proportion of patients with low grade toxicity (fatigue, pruritus, rash; q6w 46%, q3w 42%). Table: 1821P Group characteristics (median, range) q6w q3w Age (yr) 72 (33-90) 72 (42-91) Follow-up time (months) 6.2 (0.1-11) 13.2 (2.5-44) Treatment cycles given 4 (1-10) 14 (3-57) Total treatment duration (patient-months) 391 1175.Conclusions: To our knowledge, this is the first analysis of toxicity data for a q6w Pembrolizumab regime. Incidence of CSirAEs is low. Low grade toxicity was common and over the course of treatment could impact quality of life. Despite limited number of events, the q6w schedule does not appear to lead to significantly higher toxicity and should be used in view of the reduced visit burden to patients and health services.Legal entity responsible for the study: the authors.