52P - Discontinuation of immune checkpoint inhibitor (ICI) above 18 months of treatment in real-life patients with non small-cell lung carcinoma (NSCLC) : INTEPI, a multicentric retrospective study.

Background

The optimal treatment duration of ICIs for patients with NSCLC remains uncertain. In phase 3 clinical trials, treatment continued for 2 years or until disease progression, and results from CheckMate 153 trial suggest to continue beyond 1 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 16 months from ICI discontinuation, 14 (26%) patients had a tumour progression with a median time of 9 months (2-33). From discontinuation, overall survival (OS) and progression free survival (PFS) were 90% and 71% respectively at 12 months and 82% and 66% respectively at 24 months. Best tumour response at treatment discontinuation seems to be correlated to duration of disease control, with a PFS rates of 70% for complete response (CR n=11), 77% for partial response (PR n=37), 31% for stable disease (SD n=6), and 76% for CR and/or complete metabolic response with ¹⁸F-FDG PET/CT (CMR). Ten patients out of the 14 in the relapse group received a subsequent treatment: 6 were retreated with an anti-PD-1 (with best response 17% PR and 83% SD) and 4 received a localized therapy with 100% 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.

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.