Cancer Science & Therapy

Sustained Oligoclonal T Cell Expansion Correlates with Durable Response to Immune Checkpoint Blockade in Lung Cancer

Abstract

Sope Olugbile, Jae-Hyun Park, Philip Hoffman, Livia Szeto, Jyoti Patel, Wickii T Vigneswaran, Everett Vokes, Yusuke Nakamura and Kazuma Kiyotani

Purpose: Antibodies that target immune checkpoint molecules have demonstrated significant and durable clinical benefit through re-activation and proliferation of pre-existing tumor-infiltrating CD8+ T cells in a broad range of tumor types including lung cancer. Detailed characterization of T cell dynamics at clonal levels using nextgeneration T cell receptor (TCR) sequencing in large cohorts of lung cancer patients is yet reported.
Methods: We performed TCR sequencing of peripheral blood samples (and some tumors) obtained from 27 lung cancer patients undergoing single/combined immune checkpoint blockade therapies.
Results: In one responder, we found expansion of a single T cell clone (approximately 20% of the all TCR reads) in a metastatic subcutaneous lesion that showed pathologic complete response on day 17 of treatment. The same TCR CDR3 sequence was detected in 6.1% of TCR reads in the peripheral blood prior to treatment initiation and the expansion remained persistent in peripheral blood at 21.0% at week 10 and 24.3% at week 48. In other patients who showed durable response, we also found persistent oligoclonal T cell expansion in their peripheral blood which was not observed in non-responders even while they remained on therapy.
Conclusion: We found sustained expansion of oligoclonal T cell clones in lung cancer patients who had durable response to immune checkpoint blockade. This suggests possible use of longitudinal TCR sequencing to assist clinical decision-making, assess synergism with other agents, and most importantly facilitate rational development of alternative treatment strategies for non-responders.