Completion of Pembrolizumab in Advanced Non-Small Cell Lung Cancer-Real World Outcomes After Two Years of Therapy (COPILOT).

Background: Seminal trials with first-line pembrolizumab for metastatic non-small cell lung cancer (NSCLC) mandated a maximum two-years treatment. We describe real-world outcomes of a multi-site Australian cohort of patients who completed two-years of pembrolizumab.

Methods: Retrospective data were collected from the national AUstralian Registry and biObank of thoRacic cAncers (AURORA). Primary endpoints were progression rate post pembrolizumab discontinuation; and progression free survival (PFS). Local treatment of oligoprogressive disease during pembrolizumab was allowed.

Results: A total of 71 patients from six centers, median age 66.0 years, 49% male and 90% ECOG ≤ 1 were identified. Patients were Caucasian (82%) or Asian (16%); past (66%) or current (24%) smokers with mean 37 pack-years. Histology comprised 73% adenocarcinoma and 16% squamous. 18 patients (25%) had brain metastases at diagnosis. Median PD-L1 tumor proportion score (TPS) was 68%; 12 patients (17%) TPS < 1% and 43 (61%) TPS ≥ 50%. No patients had EGFR/ALK/ROS1 alterations; 29/49 tested (60%) had KRAS mutations. Median follow up was 38.7 months. Objective response rate 78.6%. Median PFS 46.1 months (95% CI 39.5-NR), not reached (46.1-NR) in PD-L1 TPS ≥ 1% versus 28.1 months (16.3-NR) in TPS < 1% (P = .013). 17 patients (24%) received additional local therapy for oligoprogression. Post pembrolizumab discontinuation, 20 patients (28%) had disease progression. Higher rates of progression occurred with TPS < 1% (OR 3.46, P = .06), without complete response (OR 5.06, P = .04), and with treated oligoprogression (OR 3.11, P = .05). 36-month landmark survival was 98.2%.

Conclusion: Patients completing two-years of pembrolizumab for NSCLC in an Australian cohort had high rates of KRAS mutation and PD-L1 expression; a proportion had brain metastases and treated oligoprogression. Progression post pembrolizumab was higher in PD-L1 TPS < 1% and in those without complete response.