Abstract only
8508
Background: Anti-PD-1 therapy produces objective and often durable responses in ~20% of unselected patients (pts) with metastatic non-small cell lung cancer (NSCLC). However, the ...role of PD-1 blockade in treating resectable NSCLC is unknown. This is the first study to test nivolumab in the neoadjuvant setting. This trial design provides an opportunity to examine anti-PD-1 mechanism of action and immunologic correlates of outcomes. Methods: Patients with Stage IB - IIIA NSCLC received 2 doses of nivolumab 3mg/kg over 4 weeks before surgery. The primary endpoint was safety in 20 patients with resected NSCLC. Efficacy was explored using objective pathologic response criteria. Correlative studies of the tumor immune microenvironment, tumor mutation and predicted neoantigen loads, and changes in T cell receptor (TCR) clonality in tumor and blood pre and post treatment were conducted. Results: 22 pts were treated. Nivolumab was well-tolerated and no surgeries were delayed. 1 pt withdrew from study preop without progression or toxicity. Among the 21 attempted resections, 1 tumor was unresectable. 9/21 (43%, 95% CI 24-63%) had a major pathologic response ( < 10% viable tumor cells in resection specimen). With a median postop follow-up of 9 months, 18 pts (86%) remain alive and recurrence free. Pre-treatment tumor exome sequencing showed a correlation between both tumor mutation and predicted neoantigen loads with pathologic response. Multiplex immunohistochemistry of pre- and post-treatment tumors showed an influx of PD-1+CD8+ T cells into responding tumors. TCR sequencing demonstrated that expanded peripheral T cell clones after treatment match clones found in the tumor. Conclusions: Neoadjuvant nivolumab in resectable NSCLC did not delay surgery. Major pathologic response rate was encouraging and compares favorably to outcomes with cisplatin-based neoadjuvant chemotherapy. Genomic analyses suggest that higher mutational and neoantigen burden could result in deeper pathologic response. Immunologic analyses support the detection of intra-tumoral T cell clones in the blood after treatment with nivolumab and may provide further insight into the molecular and immunologic features of response and non-response to PD-1 blockade. Clinical trial information: NCT02259621.
