Abstract 3307: Real-world outcomes of first-line pembrolizumab monotherapy for PD-L1-positive (TPS ≥50%) metastatic non-small cell lung cancer (NSCLC)

Abstract

Abstract Introduction Pembrolizumab monotherapy was approved in October 2016 for first-line (1L) treatment of metastatic NSCLC with PD-L1 tumor proportion score (TPS) ≥50% based on KEYNOTE-024 (KN024) trial results. A subsequent trial, KN042, confirmed overall survival (OS) benefit with pembrolizumab monotherapy over platinum doublet chemotherapy in the same population. Our aim was to investigate effectiveness of 1L pembrolizumab monotherapy in real-world settings in the US for patients clinically similar to those in KN024 and KN042 with PD-L1 TPS ≥50%. Methods This retrospective study used Flatiron Health’s nationally representative database derived from electronic health record (EHR) data. We identified patients (≥18 years) with histologically confirmed stage IV NSCLC, PD-L1 TPS ≥50%, no documented EGFR/ALK aberration, and ECOG performance status (PS) of 0-1 who initiated 1L pembrolizumab monotherapy after December 1, 2016. Patients with <6-months follow-up or participating in clinical trials were excluded. Structured and unstructured data, curated via technology-enabled abstraction, were used to determine real-world tumor response (rwTR), real-world progression (rwP), which we used to determine real-world progression-free survival (rwPFS), and OS. Results Of 186 eligible patients, 48% were male; the median age was 72 years (Table). Complete and partial tumor responses were recorded for 12 (6.5%) and 74 (39.8%) patients, respectively, with rwTR of 46.2% (95% CI 38.9-53.7%). Median rwPFS was 7.0 months; median OS was not reached (Table). Conclusions In real-world oncology practice, patients prescribed 1L pembrolizumab monotherapy for PD-L1 TPS ≥50% metastatic NSCLC tended to be older and included fewer men than in clinical trials, even after limiting to key trial eligibility criteria. Benefits observed were consistent with phase 3 trial findings, supporting the effectiveness of pembrolizumab in real-world settings. Real-world outcomes with 1L pembrolizumab monotherapy for PD-L1-positive metastatic NSCLCPatients N=186CharacteristicsAge, median (range), yr72 (46-84)Male sex, n (%)90 (48)Positive smoking history, n (%)169 (91)Squamous histology, n (%)46 (25)ECOG PS 1, n (%)111 (60)Brain metastases, n (%)†22 (12)OutcomesFollow-up, median (range), months*11.5 (6.0-17.9)rwPFSOSEvents, n (%)110 (59)62 (33)Median (95% CI), months7.0 (5.6-8.4)NR (15.1-NR)Rate at 12 months, % (95% CI)34.6% (26.8-42.5)63.6% (55.2-70.9)* Follow-up time from pembrolizumab initiation to data cutoff.† No data available on pretreatment of brain metastases.NR, not reached. Data cutoff: May 31, 2018 Citation Format: Vamsidhar Velcheti, Sheenu Chandwani, Xin Chen, M. Catherine Pietanza, Thomas Burke. Real-world outcomes of first-line pembrolizumab monotherapy for PD-L1-positive (TPS ≥50%) metastatic non-small cell lung cancer (NSCLC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3307.