1217P - B cell infiltration and memory TOX+ CD8+ T cells in stage I-II non-small cell lung cancer (NSCLC) predict response to neoadjuvant pembrolizumab: A phase I study

Background

Neoadjuvant immune checkpoint inhibitors are part of the standard of care for stage II-III resectable NSCLC. The optimal treatment for stage I-II, predictive factors, and the molecular underlying events are not known.

Methods

MK3475-223 is a phase I, investigator-initiated study (NCT02938624) to examine the safety and recommended dose/schedule of neoadjuvant pembrolizumab for stage I-II resectable NSCLC, and to study molecular mechanisms of response. MSD provided drug and financial support. Pathology of resected specimens identified responders (R; major pathologic response; MPR; ≤10% remaining viable cancer cells). NanoString’s GeoMx Digital Spatial Profiler (GeoMx-DSP) quantified proteins (n=72) and mRNA (n=73 genes) expression in regions of interest (CD8+ or pan-cytokeratin+). Immunohistochemistry and Multiplexed Ion Beam Imaging (MIBI; quantifying 40 proteins) were conducted on the samples.

Results

26 patients (pts) initiated treatment, 2 pts (8%) had adverse events precluding surgery, 1 pt refused surgery. 7 pts (27%, 95% C.I 10-44%) achieved MPR. By GeoMx-DSP pre-treatment, CD20 was the most differentially upregulated protein in R vs. non-R (4.7-fold, p=0.002). In R tumors, the protein found to be most upregulated post- vs. pre-treatment was CD20 (6.2-fold, p=0.001) as well as its encoding gene, MS4A1 (2.4-fold, p=0.006). MIBI subclassified and characterized a total of 705,997 cells. Pre-treatment MIBI found CD8+ T cells to express higher TOX, LAG3, and TIM3 protein in R vs. non-R. CD8+ T cells had a memory phenotype in R samples, specifically CD45RO+TOX+TCF1+. In post-treatment specimens, plasma cells (specifically CD31+ plasma cells) and B-cells were elevated, and T-regs and neutrophils were reduced in R vs. non-R. Tertiary lymphoid structures (TLS) were more prevalent in R compared to non-R (3.2-fold, p<0.05) in post-treatment samples.

Conclusions

Pre-treatment tumor-infiltrating B-cells as well as memory TOX+CD8+ T cells were correlated with MPR to neoadjuvant pembrolizumab in stage I-II NSCLC. B-cell infiltration increased following treatment in R tumors. Plasma cells (specifically CD31+ plasma cells) were more common in R vs. non-R post-treatment.

Clinical trial identification

NCT02938624.

Editorial acknowledgement

Legal entity responsible for the study

Sheba Medical Center, Ramat Gan, Israel.

Funding

MSD.

Disclosure

J. Bar: Financial Interests, Personal, Advisory Board: MSD, Takeda, Roche, Pfizer, AbbVie, Bayer, AstraZeneca, Merck-Serono, J-C healthcare, Medison Pharma, Amgen; Financial Interests, Personal, Invited Speaker: BMS; Financial Interests, Institutional, Local PI: MSD, Roche, Takeda, AbbVie; Financial Interests, Institutional, Other, local sub-investigator: Novartis; Financial Interests, Institutional, Research Grant: OncoHost, ImmuneAI, AstraZeneca; Non-Financial Interests, Other, Committee member: IASLC. D. Urban: Financial Interests, Personal, Advisory Board: Merck Sharp and Dohme Israel, J-C Healthcare, AstraZeneca, Roche, BMS, Takeda, Medison Pharma. S.N. Daher: Financial Interests, Personal, Advisory Board: Merck Sharp & Dohme; Non-Financial Interests, Personal and Institutional, Local PI: Merck Sharp & Dohme. H. Gantz Sorotsky: Financial Interests, Personal, Speaker, Consultant, Advisor: Roche, MSD, AstraZeneca, Takeda, Astellas, BMS, Medison, Janssen, Pfizer, Merck, Novartis. A. Onn: Financial Interests, Personal, Speaker, Consultant, Advisor: MSD, BMS, Amgen, Medison Pharma, AstraZeneca ; Financial Interests, Personal, Steering Committee Member: Pfizer. R.Y. Kremer: Financial Interests, Personal, Speaker, Consultant, Advisor: MSD. L. Keren: Financial Interests, Personal, Advisory Board: Nucleai, Compugen. All other authors have declared no conflicts of interest.