Citations

e19013 Background: Mutation profiling to assess for potentially druggable mutations in NSCLC is being offered at an increasing number of cancer centers throughout North America and internationally. Although data continue to accumulate for the potential value of mutation testing in designing chemotherapeutic regimens, the treatment impact of obtaining information beyond assessment of EGFR and ALK status remains unclear. How best to obtain and clinically utilize these data, including information from exome and whole genome sequencing, also remains unclear. Methods: Patients were reviewed electronically in a multidisciplinary conference regarding indications for testing and results of mutation profiling from various methods, including the mass-spec based LungCarta test, targeted NexGen sequencing, exome, and whole genome sequencing. Outcomes of the multidisciplinary review were communicated back to treating physicians. Results: Mutation testing was performed on 200 patients using a variety of approaches. The majority (>150) were surgically resected stage I and II tumors. Mutations in at least 1 major cancer driver gene, including EGFR, KRAS, MET, BRAF and PIK3CA, were found in 47% of all patients tested. EGFR mutations were present in 14.8% of patients tested, KRAS 21.3%, BRAF 2.6%, PIK3CA 3.2%, and MET 4.5%. A total of 8 patients underwent either exome or whole genome sequencing. A limited number of patients (<10) had mutation results that impacted treatment decisions from this cohort. Conclusions: Mutation profiling can influence treatment decisions in NSCLC, but at a low frequency. The role of exome and or whole genome sequencing for patients with NSCLC is evolving and remains undefined.

7568 Background: The molecular events in the initiation and progression of invasive lung adenocarcinoma remain poorly characterized. These tumors are thought to develop through an adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), invasive adenocarcinoma (AD) sequence. The goal of our study was to assess lineage relationships between in situ and invasive components within adenocarcinomas with prominent lepidic growth patterns. Methods: Frozen tissue from fourteen lung adenocarcinomas with mixtures of AD together with an adjacent in situ component (AIS), varying in ratio between 40 to 80%, were selected from our Lung Specimen Registry. Laser capture microdissection (LCM) of each component was performed separately for each tumor. Genomic DNA was isolated using a direct in situ whole genome amplification (WGA) methodology, and Next Generation Sequencing performed using an Illumina Mate Pair (MP) library protocol. MP sequence reads were mapped to the human genome and primers spanning the fusion junctions were used in validation PCRs. Results: Genomic break points identical and unique to a specific patient were identified between the AIS and AD components in 13 (of 14) cases. The total number of events per case ranged from 4-215, and the number of identical events shared between the AIS and AD components ranged from 30 to 90%. Recurrent genomic breakpoints between cases were also observed, with the 2 most common involving 8q24.3 in 5 cases and FAM19A2 on chromosome 12 in 4 cases. PCR validation of selected genomic alterations confirmed the genomic break points identified from sequencing in both the AIS and AD in all cases. Interestingly, we also observed a limited number of genomic alterations present in a zonal distribution of surrounding normal lung around the tumor mass. Conclusions: Our study demonstrates unique chromosomal alterations present in both the AIS and AD components of individual lung tumors with features of lepidic growth. These data provide evidence for lineage relationship and clonal relatedness between the two components, and provide genomic evidence for a model of stepwise progression from AIS to invasive AD in this subset of lung adenocarcinomas.

Abstract Introduction: While most small cell lung cancer (SCLC) patients die within a few months, a sub-group of patients survive for many years. Factors determining long-term survivorship remain largely unknown. We present the first comprehensive comparative genomic and tumor microenvironment analyses of small cell lung cancer (SCLC) between patients with long term (LTS) and expected (EXS) survival times. Methods: We compared surgically resected tumors of 23 LTS (survival &gt; 4 years) and 18 EXS (survival ≤ 2 years). There were no differences in clinical variables including TNM staging and curative versus non-curative intend surgery between the groups. Gene expression profiling was performed by microarrays and tumor microenvironment analyses were by IHC of prominent immune related markers. Results: Immune related genes and pathways represented the majority of the differentially overexpressed genes in LTS compared to the EXS. The differences in the immunological tumor-microenvironment were confirmed by quantitative immuno-staining. Increased numbers of tumor infiltrating and associated lymphocytes were present throughout tumors of LTS. Several differentiating patterns of enhanced anti-tumor immunity were identified. While some areas of LTS tumors also harbored higher numbers of suppressive immune cells (monocytes, regulatory lymphocytes, and macrophages), ratios of these suppressive cells to CD3+ lymphocytes were generally lower in LTS tumors indicating a more tumor suppressive microenvironment. Conclusions: Our data demonstrate that long-term survivorship of SCLC patients is strongly influenced by the presence of anti-tumor immune cells in the tumor microenvironment. Characterization of the anti-tumor immune responses may identify opportunities for individualized immunotherapies for SCLC. Citation Format: Farhad Kosari, Prasuna Muppa, Simone Terra, Anurag Sharma, Aaron Mansfield, Marie Christine Aubry, Nafiseh Janaki, Aqsa Nasir, Tobias Peikert. Anti-tumor immunity is a key determinant of small cell lung cancer survivorship [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 4577.

29 Background: CRS-207 is a live, attenuated, double-deleted Listeria monocytogenes (LADD) engineered to stimulate immune response to mesothelin. In a phase I trial of 60 MPM patients, 34% of subjects had tumor reduction (range -1 to -47%) following 2 doses of CRS-207 alone. In KEYNOTE-028 pembro showed activity in PDL1+ (≥1% by IHC) MPM, with an objective response rate (ORR) of 20% (5/25) and stable disease in 52% of subjects who had failed or did not receive chemotherapy. Subsequent studies of pembro have shown similar results in MPM. Results from a pre-clinical murine lung tumor model (CT26hMeso) showed anti-PD-1 enhanced LADD-induced tumor response. The study described here evaluated the efficacy of combination therapy of CRS-207/pembro. Methods: Adults with epithelial/biphasic MPM, ≤2 prior lines, progression on pemetrexed and platinum-based therapy, and no prior immunotherapies were enrolled. CRS-207/pembro were administered IV Q3W for 4 cycles, after which pembro continued Q3W and CRS-207 changed to Q6W. Response was assessed Q6W by modified RECIST for MPM (Byrne and Nowak, 2004). The primary endpoint was ORR; secondary endpoints included DOR, disease control rate (DCR), progression-free survival (PFS) and overall survival. Pre- and on-treatment blood and tumor samples were collected. Shedding and blood clearance of CRS-207 were evaluated. Results: 9/10 subjects were evaluable for response. No responses were observed; DCR was 11% (1/9 with SD) and PFS ranged from 3.4 to 8.9 weeks. Most common treatment related adverse events were chills, pyrexia and nausea. 3/10 subjects evaluated were PDL-1 negative by IHC. Of 6 subjects who underwent clearance and shedding evaluation, CRS-207 was detected in blood in 1 at 18-24 hrs after the first CRS-207 dose and cleared by the next evaluation at Day 4; shedding samples (urine, fecal, and saliva) tested negative. Conclusions: The toxicity profile of CRS-207/pembro combination was consistent with the safety profile of each component alone. No evidence of clinical activity was observed. Based on the results and an overall evaluation of the program, the clinical development of CRS-207 was discontinued. (NCT01675765) (NCT02054806). Clinical trial information: NCT03175172.