1491P - PD-L1 TPS ≥50% predicts durable response after discontinuing immune checkpoint inhibitors in metastatic non-small cell lung cancer patients

Background

The optimal duration of immune checkpoint inhibitors (ICI) in metastatic non-small cell lung cancer (NSCLC) remains uncertain. Some physicians administer ICI for 2 years then discontinue it according to the designs of clinical trials, while other physicians continue ICI until progression. This study aims to explore the clinical course after discontinuation of ICI and identify factors related with durable responses after ICI cessation.

Methods

We retrospectively analyzed 45 patients with metastatic NSCLC who received ICI for ≥1.5 years and then discontinued treatment. All patients showed complete response or partial response or stable disease. Patients who initiated ICI between Jan 2014 and Dec 2020 were enrolled. Clinical factors including PD-L1 status were analyzed.

Results

The median duration of ICI treatment was 23.4 months, and the median follow-up duration from ICI discontinuation was 14.1 months. Thirty-five patients (77.7%) showed durable response after ICI cessation which lasted for median 17.0 months without any treatment, while 10 patients showed disease progression. Durable response was significantly associated with PD-L1 TPS ≥50% (28/31, OR 0.12, 95% CI 0.01-0.80, p=0.013). PD-L1 TPS ≥50% was significantly associated with longer PFS (median not reached vs. 41.9 months, HR 0.16, 95% CI 0.04-0.68, p=0.005). In multivariate analysis, only PD-L1 TPS ≥50% was an independent predictor of longer PFS after ICI discontinuation (HR 0.17, 95% CI 0.04-0.71, p=0.015). Table: 1491P

Baseline characteristics

Conclusions

PD-L1 TPS ≥50% predicts durable response without any treatment after ICI discontinuation in metastatic NSCLC patients treated with ≥1.5 years of ICI. Further biomarker research is required to identify which patients should continue receiving ICI and which can be tried with ICI cessation.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

B. Keam: Financial Interests, Personal, Invited Speaker: Merck, Lily; Financial Interests, Personal, Advisory Board: Handok, Trial Informatics, Immun Oncia, NeoImmuneTech, BeiGene; Financial Interests, Personal, Coordinating PI: MSD Oncology, AstraZeneca, Ono Pharmaceutical. J. Youk: Financial Interests, Personal, Invited Speaker: AstraZeneca; Financial Interests, Personal, Advisory Board: Novartis. M. Kim: Financial Interests, Personal, Advisory Board: Ipsen, Bristol Myers Squibb/Ono Pharmaceutical, Eisai, Yuhan, MSD, Pfizer; Financial Interests, Personal, Invited Speaker: Novartis, Astellas, MSD. T.M. Kim: Financial Interests, Personal, Advisory Board: AstraZeneca, Janssen, Novartis, Takeda, Samsung Bioepis, Regeneron; Financial Interests, Personal, Research Grant: AstraZeneca-KHIDI; Non-Financial Interests, Principal Investigator: AstraZeneca/MedImmune, Boryung, Hanmi, Janssen, Boehringer Ingelheim, Novartis, Takeda, Sanofi, Roche/Genentech, Merck Sharp & Dohme Corp, Merck Serono, Regeneron, Genmab, Bayer, Rapt Therapeutics, Blueprint Medicines Corporation, Black Diamond Therapeutics, AbbVie, Amgen, Beyondbio Inc, Fore Biotherapeutics, Dizal Pharmaceutical, Incyte Corporation. D. Kim: Financial Interests, Personal, Invited Speaker: Korean Cancer Association, Korean Society of Medical Oncology, Korean Association for Lung Cancer, Taiwan Lung Cancer Society, Japan Cancer Association; Financial Interests, Personal, Other, Scientific Advisor: Health Insurance Review & Assessment Service, Korea; Financial Interests, Personal, Writing Engagement, Medical writing assistance: Amgen, AstraZeneca, Boehringer Ingelheim, BMS, Chong Keun Dang, Daiichi Sankyo, GSK, Novartis, Pfizer, MSD, Merck, Roche, Takeda, Yuhan; Financial Interests, Institutional, Local PI, Clinical Trial Funding: Hanmi, Alpha Biopharma, Amgen, AstraZeneca/Medimmune, Boehringer Ingelheim, Daiichi Sankyo, Janssen, Merus, Mirati Therapeutics, MSD, Novartis, Ono Pharmaceutical, Pfizer, Roche/Genentech, Takeda, TP Therapeutics, Xcovery, Yuhan, Bridge BioTherapeutics, GSK; Financial Interests, Institutional, Coordinating PI, Clinical Trial Funding: Chong Keun Dang; Financial Interests, Institutional, Research Grant, Laboratory research funding to my institution: InnoN; Non-Financial Interests, Advisory Role: Amgen, BMS / Ono Pharmaceuticals, Daiichi Sankyo, Janssen, GSK, Pfizer, AstraZeneca, SK Biopharm, Takeda, Yuhan; Non-Financial Interests, Member of Board of Directors: Korean Cancer Association, Korean Society of Medical Oncology, Korean Association for Lung Cancer, Asian Thoracic Oncology Research Group; Other, Travel support for advisory board meeting attendance: Amgen, Daiichi Sankyo; Other, Clinical trial research funding to my institution: Asian Thoracic Oncology Research Group. All other authors have declared no conflicts of interest.