Immuno-oncology biomarker study in non-small cell lung cancer harboring oncogenic driver alterations: LC-SCRUM-IBIS

Abstract

Abstract Background The efficacy of immune checkpoint inhibitors (ICI) and PD-L1 status in patients with advanced non-small cell lung cancer (NSCLC) harboring oncogenic alterations has not been fully investigated. We initiated this immuno-oncology biomarker study as part of nationwide genomic screening by LC-SCRUM-Japan (LC-SCRUM-IBIS). Methods: Lung cancer patients enrolled in LC-SCRUM-IBIS underwent targeted NGS with Oncomine Comprehensive Assay, PD-L1 IHC assays and further whole-exome sequencing (WES) to determine tumor mutation burden. According to subtype of oncogenic alterations, the efficacy of ICI and PD-L1 status were analyzed. Results: Between Feb 2017 and May 2018, 1017 lung cancer patients were enrolled. Of these, 832 NSCLC patients were included in this analysis. Targeted NGS showed that major oncogenic alterations included 157 EGFR, 83 KRAS, 33 MET, 28 HER2, 27 FGFR, 22 PIK3CA, 19 ALK, 15 ROS1, 10 RET, 5 BRAF and others. High expression of PD-L1 (> 50% of tumor cells by 22C3) were observed in RET (70%), MET (67%), ROS1 (53%), KRAS (41%) and BRAF (40%) positive tumors. 105 patients were evaluable for the efficacy of ICI. Among them, 104 were treated with PD-1/PD-L1 monotherapy and only 1 in combination therapy of ICI. Median treatment line was 2 (range, 1-9). The response rate was 19% (20/105) and median progression-free survival (PFS) and overall survival (OS) were 3.3 and 18.3 months. In 50 patients harboring at least one oncogenic alterations, the response rate, PFS and OS were 18% (9/50), 3.3 and 24.8 months. Among 9 responders to ICI, 3 had KRAS, 2 had MET and 1 each had ALK/EGFR/HER2/RET. Six (26%) of 23 patients with both high PD-L1 expression and at least one oncogenic alterations responded to ICI. Conclusions: PD-L1 status seemed to vary among patients with advanced NSCLC harboring oncogenic alterations. New biomarker for ICI therapy in this population should be moreover explored. Updated results on WES analysis will be presented at the meeting.