Correlation between PD-L1 level and immunotherapy outcome in NSCLC in Lebanon, 2012-2018: A multicenter observational review.

Abstract

e20524 Background: Immunotherapy targeting the PD1/PDL1 checkpoint pathway represents an important innovation in lung cancer treatment. In our research, we evaluate the correlation of PD-L1 expression with clinical outcomes (progression free survival, overall survival, objective response rate) in lung cancer patients in 4 centers in Lebanon. Methods: The 57 patients enrolled in this observational study were stage IIIB/IV NSCLC and SCLC who received immunotherapy with nivolumab, pembrolizumab or atezolizumab at any line of treatment, and were recruited between February 2012 and august 2018. Immunotherapy was continued until progression, death or unacceptable toxicity. PD-L1 expression was assessed on tumor samples either on diagnosis or at progression. Patients were divided into 3 categories according to PD-L1 level (< 1, 1-49, > 50%). Progression free survival defines the time from randomization to disease progression after each line of therapy. Overall survival defines time from randomization to death from any cause. Results: 70.18% had adenocarcinoma, 26.32% had squamous cell carcinoma, 1.75% had small cell lung cancer and one pathology was missing from the file. 66.66% were stage IV at diagnosis, 26.31% were stage 3. PD-L1 expression was > 50% in 40.35% of patients, 24.56% had a level between 1 and 50% and the remaining had a value of less than 1%. PD-L1 was missing or not done in 15.79%. Median PFS was 13.9 months. Median OS was 14.2 months. 22.81% received immunotherapy as first line and 75% of the remaining patients upon first progression. PFS1 was 4.2 months. Mean time to first progression on immunotherapy was 3.6 months in patients with PD-L1 > 50%, 10.5 months in PD-L1 between 1 and 50% and 14.3 months in those who had PD-L1 < 1%. At the date of data cutoff, 49.12 % of patients were still receiving immunotherapy. No grade 3 or 4 immune related adverse events were seen during follow-up. Conclusions: The efficacy and safety of anti-PD-1 medications for advanced NSCLC were comparable in real-world and clinical settings. Prediction of treatment response from tumor PD-L1 expression seemed less practical than that was expected