Discontinuation of immune checkpoint inhibitor (ICI) above 18 months of treatment in real-life patients with non-small cell lung cancer (NSCLC): INTEPI, a multicentric retrospective study.
9082 Background: The optimal treatment duration of ICIs for patients with NSCLC remains uncertain. In phase 3 clinical trials, treatment continued for two years or until disease progression, and results from CheckMate 153 trial suggest to continue beyond one year. Real life data are missing. Methods: This multi-centric retrospective study presents data on real-life patients who discontinued treatment after at least 18 months of ICI monotherapy, their tumour being still controlled. Their characteristics, the causes of discontinuation of ICI, and their outcome are described. Results: Between July 2015 and May 2018, 107 patients had their tumour controlled after at least 18 months of treatment. Among them, 54 (50%) patients discontinued ICI: 76% male, median age 63, 91% PS 0-1, 54% adenocarcinoma, 20% with brain metastases, PD-L1 expression level available for 18 (33%) patients (2 < 1%, 8 btw 1-50% and 8 > 50%), 93% treated after 1st line. The median duration of treatment was 26 months. Treatment was stopped by choice of the prescriber and toxicity in 46% and 22% respectively. With a median follow up of 21 months from ICI discontinuation, 18 (33%) patients had a tumor progression with a median time of 10 months (2-33). From discontinuation, overall survival (OS) and progression free survival (PFS) were 90% and 71% respectively at 12 months and 84% and 63% respectively at 24 months. Duration of disease control after ICI cessation seemed to be correlated to the best tumor response at treatment discontinuation, with a PFS rates at 12 months of 73% for complete response (CR n = 11), 77% for partial response (PR n = 37), 22% for patients with stable disease (SD n = 6), 80% for CR and/or complete metabolic response with 18F-FDG PET/CT (CMR) and 65% for others. Fourteen patients out of the 18 in the relapse group received a subsequent treatment : 7 were retreated with ICI (with best response 14% PR and 86% SD) and 5 received a localized therapy with 60% CR. Conclusions: Our study in real life provides new insight into the long-term outcomes of patients treated with ICI for at least 18 months before discontinuation in the absence of PD. CR and CMR with FDG-PET before therapy discontinuation may be a positive factor for a prolonged disease control upon discontinuation.