Abstract 1893
Background
The SMARCA4 catalytic ATPase, can be inactivated by several types of genomic alterations (GA) in NSCLC. SMARCA4 deficient (d) NSCLC is an aggressive subtype of primary lung adenocarcinoma that is often confused with metastatic disease to the lung.
Methods
From a series of 40,319 clinically advanced NSCLC, 2,840 (7%) SMARCA4d and 37,479 (93%) SMARCA4i cases underwent hybrid capture-based CGP using FFPE material. Microsatellite instability (MSI) was determined on 114 loci and tumor mutational burden (TMB) and (mutations (mut) per/ Mb) was determined on 1.1 Mbp of sequenced DNA. PD-L1 expression was measured by IHC (Dako 22C3).
Results
SMARCA4d was inactivated by short variant base substitutions and truncations (88%), deletions (9%), duplications (1%), rearrangement/fusions (1%). SMARCA4d patients were slightly younger and featured significantly fewer females (Table). At 3.2 vs 5.6 GA/tumor, SMARCA4d tumors had significantly fewer driver-type GA than SMARCAi tumors. Although non-targetable GA in TP53 and KRAS were similar, SMARCA4d cases features significantly lower frequencies of the EGFR and PIK3CA SV targets and fusions in ALK, ROS1 and NTRK1-3 genes. In contrast, SMARCA4d tumors had a significantly higher frequency of STK11 mutations while also having a higher median TMB and greater proportion of cases with > 10 and > 20 mut/Mb. CDK4/6 GA were more frequent in the SMARCA4i cases.Table:
1583P
| SMARCA4 Deficient NSCLC | SMARCA4 Intact NSCLC | Significance | |
|---|---|---|---|
| Cases | 2,840 | 37,479 | |
| % Male/female | 57/43 | 49/51 | P < 0.0001 |
| Median age | 64 | 67 | NS |
| GA/tumor | 3.2 | 5.6 | P < 0.0001 |
| TP53 | 70% | 64% | NS |
| KRAS | 28% | 30% | NS |
| EGFR | 7% | 18% | P < 0.0001 |
| STK11 | 34% | 13% | P < 0.0001 |
| PIK3CA | 5% | 10% | P < 0.0001 |
| RB1 | 6% | 8% | NS |
| MET | 4% | 5% | NS |
| BRAF | 4% | 5% | NS |
| ERBB2 | 6% | 4% | NS |
| CDK4 | 2% | 4% | P < 0.0001 |
| CDK 6 | 2% | 2% | NS |
| ALK ROS1 NTRK1/3 | 2% | 5% | P < 0.0001 |
| PD-L1 (CD274) amp | 1% | 1% | NS |
| PD-L1 Low | 26% | 27% | NS |
| PD-L1 High | 18% | 29% | P < 0.0001 |
| Median TMB (mut/Mb) | 12.2 | 6.1 | P < 0.0001 |
| TMB > 10 mut/Mb | 60% | 35% | P < 0.0001 |
| TMB > 20 mut/Mb | 27% | 10% | P < 0.0001 |
| MSI High | 0.8% | 0.2% | NS |
Conclusions
SMARCA4d NSCLC is characterized by pleomorphic histology, TTF1- IHC and significant reduction in targetable driver mutations in genes such as EGFR, ALK, ROS1 and NTRK1-3. Despite new evidence that SMARCA4d tumors can respond to cell cycle inhibitors such as palbociclib, the CDK4/6 mutation frequencies is not increased in this tumor subset. Higher TMB levels in SMARCA4d NSCLC suggests strong potential for immunotherapy benefit, but the significantly enriched STK11 GA frequency may reduce overall response rates to checkpoint inhibitors.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Foundation Medicine.
Funding
Foundation Medicine.
Disclosure
D. Lin: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. J.A. Elvin: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. J. Vergilio: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. J.K. Killian: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. N. Ngo: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. S. Ramkissoon: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. E. Severson: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. A. Hemmerich: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. D. Duncan: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. C. Edgerly: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. S.M. Ali: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. A.B. Schrock: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. J. Chung: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. E.S. Sokol: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. P. Reddy: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. K. McGregor: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. V.A. Miller: Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. B.M. Alexander: Leadership role, Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. J.S. Ross: Leadership role, Shareholder / Stockholder / Stock options, Full / Part-time employment: Foundation Medicine. All other authors have declared no conflicts of interest.
Resources from the same session
5128 - IO-Synthesise NSCLC: A pooled analysis of real-world survival outcomes for non-small cell lung cancer patients treated with nivolumab in France and Germany
Presenter: Adrien Dixmier
Session: Poster Display session 1
Resources:
Abstract
2066 - Second-line (2L) real-world treatment (tx) patterns and outcomes in patients (pts) with advanced/metastatic non-small cell lung cancer (NSCLC) treated with first line (1L) immuno-oncology (IO) monotherapy (mono tx)
Presenter: Denis Talbot
Session: Poster Display session 1
Resources:
Abstract
5919 - Real-world effectiveness of nivolumab monotherapy after prior systemic therapy in advanced non-small cell lung cancer (NSCLC) in the United States
Presenter: David Stenehjem
Session: Poster Display session 1
Resources:
Abstract
3368 - Pembrolizumab as first-line treatment in NSCLC with PD-L1 ≥50%: Real life results from an all-comer population
Presenter: Nikolaj Frost
Session: Poster Display session 1
Resources:
Abstract
3775 - Patients with metastatic non-small cell lung cancer without molecular alterations or PD-L1 expression in Germany. Treatment and first outcome from the prospective German Registry Platform CRISP (AIO-TRK-0315)
Presenter: Frank Griesinger
Session: Poster Display session 1
Resources:
Abstract
3926 - Impact of second-line (2L) immune checkpoint inhibitors (ICIs) on the treatment (Tx) of advanced non-small cell lung cancer (NSCLC) in a UK centre: a REAL-Oncology analysis from the I-O Optimise initiative
Presenter: Michael Snee
Session: Poster Display session 1
Resources:
Abstract
5068 - First line pembrolizumab for NSCLC with PD-L1 TPS > 50% in a first French real life cohort
Presenter: Karim Amrane
Session: Poster Display session 1
Resources:
Abstract
1182 - Interstitial lung disease induced by immune-checkpoint inhibitors correlates with prognosis of advanced non-small-cell lung cancer patients
Presenter: Teppei Sugano
Session: Poster Display session 1
Resources:
Abstract
2297 - Phase II study to evaluate the peripheral blood mononuclear cell biomarker for nivolumab efficacy on previously treated non-small cell lung cancer subjects (NEJ029B: IMMUNITY-ONE)
Presenter: Yosuke Kawashima
Session: Poster Display session 1
Resources:
Abstract
2739 - Efficacy and safety of nintedanib + docetaxel in lung adenocarcinoma patients (pts) following treatment with immune checkpoint inhibitors (ICIs): Updated results of the ongoing non-interventional study (NIS) VARGADO (NCT02392455)
Presenter: Christian Grohe
Session: Poster Display session 1
Resources:
Abstract