1476P Outcomes to first-line pembrolizumab in patients with advanced NSCLC and high PD-L1 expression: A Spanish multicentric study

Pembrolizumab stands as a first-line option for patients (p) with advanced NSCLC and high PD-L1 expression (≥50%). Several factors influenced outcomes such as antibiotic (AB) exposure, low body mass index (BMI), certain metastasic location (e.g. bone), or ECOG-PS of 2. We performed a multicenter retrospective study in 8 Spanish hospitals to evaluate clinical outcomes according to several factors in patients with stage IV high PD-L1 expression NSCLC treated with first-line pembrolizumab in clinical practice. We included data from patients treated between May 2017 and July 2022. Among the 494 patients, median age was 67.2 years (29.4-89.43), 379p (76.7%) were male, 138p (27.9%) had an ECOG PS of 0, 269p (54.5%) had an ECOG PS of 1, 87p (17.6%) had an ECOG of ≥2 and 230p (46.6%) had a BMI of <24.9. 158p (32.0%) had bone metastases. 175p (35.5%) had antibiotic (AB) exposure during treatment with pembrolizumab or 4 weeks before initiation, and 210p (42.5%) underwent treatment with corticosteroids during treatment with pembrolizumab or 4 weeks before initiation [>10mg prednisone equivalent (>10mg PDNe)]. 308p (62.3%) had proton pump inhibitors (PPi) exposure. With a median follow-up of 12.6 months (m), the median overall survival (OS) and the progression-free-survival (PFS) were 16.9m (95% CI 12.9-19.2) and 9.9m (95% CI 7.7-12.1), respectively, and the overall response rate (ORR) was 43.3%. Multiple variables were associated with survival after univariate analysis (Table). After multivariate analysis, corticosteroid treatment (HR 1.41) and ECOG (HR 2.40) maintained a prognostic impact: poor PS (ECOG ≥2) and having been exposed to corticosteroids were predictive of poor outcome.Table: 1476PMedian OS - months (95% CI)p-value (univariate analysis)ECOG PS0 (N=138)36.7 (20.3-53.2)1 (N=269)14.8 (11.7-17.9)2 (N=81)2.7 (1.8-3.7)3 (N=6)0.3 (0.03-0.2)< 0.001Corticosteroid exposureNo (N=284)22.3 (17.9-26.7)Yes (N=210)11.4 (8.0-14.7)< 0.001Reason for treatment with corticosteroidsirAEs (N=57)NRBaseline conditions/symptom management (N=153)4.8 (1.4-8.3)< 0.001PPi exposureNo (N=186)23.0 (18.1-28.0)Yes (N=308)12.6 (9.5-15.7)0.002Bone metastasesNo (N=336)20.2 (16.6-23.8)Yes (N=158)9.3m (4.9-13.7)0.001Best response to IOCR (N=30)NRPR (N=184)NRSD (N=113)15.7 (13.8-17.8)PD (N=117)4.0 (3.1-5.0)Not evaluated (N=50)0.8 (0.6-1.0)<0.001 Open table in a new tab . First-line pembrolizumab in advanced NSCLC patients with high PD-L1 expression should only be used in patients with good PS. Patients with PS 2 are in urgent need of new treatment approaches.