BACKGROUND Anti-PD-(L)1 therapy alone (cancer immunotherapy [CIT]-mono) or combined with platinum-based chemotherapy (CIT-chemo) is used as 1L treatment for patients with metastatic Nsq-NSCLC with a PD-L1 tumor proportion score (TPS) >50% (high expression). Our study compared clinical outcomes with CIT-mono vs CIT-chemo in this specific clinical scenario.
METHODS This was a retrospective cohort study using the nationwide Flatiron Health Electronic Health Record-derived de-identified US database. Patients with metastatic Nsq-NSCLC with high PD-L1 expression initiating 1L CIT-mono or CIT-chemo between 24 Oct 2016 and 28 Feb 2019 were followed until study end (28 Feb 2020). We compared overall survival (OS) and real-world progression-free survival (rwPFS) using Kaplan-Meier methodology. Hazard ratios (HR) were adjusted (aHR) for differences in baseline characteristics.
RESULTS Patients with PD-L1-high Nsq-NSCLC treated with CIT-mono (n=351) had higher proportions of poor prognostic baseline characteristics (notably, age and metastatic disease type) than patients treated with CIT-chemo (n=169; Table). With a median follow-up of 19.9 mo for CIT-chemo vs 23.5 mo for CIT-mono, median OS and rwPFS did not differ between the two groups (median OS: CIT-chemo, 21.0 mo vs CIT-mono, 22.1 mo, aHR=1.03, 95% CI 0.77-1.39, P=0.83; median rwPFS: CIT-chemo, 10.8 mo vs CIT-mono, 11.5 mo, aHR=1.04, 95% CI 0.78-1.37, P=0.81). CIT-chemo only showed significant and meaningful improve-ment in OS and rwPFS vs CIT-mono in the never-smoker subgroup, albeit a small sample of patients (n=50; OS HR=0.25, 95% CI 0.07-0.83, interaction P=0.02; rwPFS HR=0.40, 95% CI 0.17-0.95, interaction P=0.04).
CONCLUSIONS Except in a subgroup of patients with no smoking history, sparing the chemotherapy in 1L CIT treatment does not appear to impact survival outcomes.