Venous thrombotic events and impact on outcomes in patients treated with first-line single-agent pembrolizumab in PD-L1 ≥ 50% advanced non small cell lung cancer.

Background: Few data are available on the impact of venous thrombotic events (VTE) in patients with metastatic non-small cell lung cancer (mNSCLC) treated with immunotherapy.

Methods: This is a secondary analysis of the ESKEYP study, a national, retrospective, multicenter study that consecutively included all PD-L1 ≥ 50% mNSCLC patients who initiated first-line treatment with pembrolizumab monotherapy. From May 2017 to November 2019, 845 patients were included (from availability of pembrolizumab in this indication in France to the authorization of the combination with chemotherapy). Impact of VTE and patient characteristics were analyzed.

Results: Of the 748 patients (88.5%) with available data, the incidence of VTE was 14.8% (111/748). At pembrolizumab initiation, Khorana score was ≥ 2 for 55.0% (61/111) of them. Recurrence of VTE was reported for 4 of the 111 patients and 5 had bleeding complications. Patients with VTE were significantly younger, had more frequently long-term corticosteroids treatment and more often liver metastases. Progression-free survival (PFS) was significantly shorter in patients with VTE compared to patients without VTE: 6.1 (95% CI 4.1-9.0) months vs. 8.3 (6.9-10.3) months (p = 0.03). VTE did not significantly impact overall survival (OS): 15.2 (10.0-24.7) months with VTE and 22.6 (18.4-29.8) months without VTE (p = 0.07). In multivariate analysis for PFS and OS, HRs for VTE were 1.3 (0.99-1.71), p = 0.06 and 1.32 (0.99-1.76), p = 0.05.

Conclusion: The incidence of VTE appears to be as high with in first-line immunotherapy as with chemotherapy in patients with mNSCLC, with in patient with VTE, a no significant trend for lower PFS and OS in multivariate analysis. more marked impact on PFS than on OS.