Abstract 1824P
Background
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 its clinical impact and investigate potential risk factors for VTE/ATE.
Methods
Patients treated with an immune checkpoint inhibitor at the Medical University of Vienna from 2015-2018 have been identified using the in-house pharmacy records (n=580; most frequent entities: 35.6% melanoma, 29.3% lung-cancer; 89% 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 clinical outcomes (mortality & progression of disease).
Results
Over a median follow-up of 8.0 months, 39 VTE and 7 ATE were observed. Cumulative incidences of VTE and ATE were 12.9% [95%CI: 7.7-19.5)] and 1.9% [0.7-4.0]. Occurrence of VTE was associated with increased mortality (transition hazard-ratio (THR): 3.16 [95%CI: 2.06-4.86]) and an increase in risk of early disease progression (THR: 3.51 [95%CI: 2.25-5.48]). Disease-stage (all VTE occurred in stage IV tumors) and history of VTE (sHR: 3.23 [1.68-6.20]) predicted VTE occurrence. 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.
Conclusions
Patients with cancer under immune checkpoint inhibitor therapy are at high risk of thromboembolism, especially VTE. Clinical predictors of VTE were advanced disease and history of VTE. Furthermore, VTE occurrence under immunotherapy was associated with increased risk of mortality and disease progression.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
This work was supported by the Anniversary Fund of the Austrian National Bank [grant number 17828]; and the Austrian Science Fund (FWF) [Special Research Program (SFB) 54].
Disclosure
All authors have declared no conflicts of interest.